FAS Moving Advanced Nuclear Energy Systems to Global Deployment

FAS Moving Advanced Nuclear Energy Systems to Global Deployment
FAS
Moving Advanced Nuclear Energy
Systems to Global Deployment
A special report published by the Federation of American Scientists
Charles D. Ferguson
August 2015
About FAS
Founded in 1945 by many of the scientists who built the first atomic bombs, the Federation
of American Scientists (FAS) is devoted to the belief that scientists, engineers, and other
technically trained people have the ethical obligation to ensure that the technological fruits
of their intellect and labor are applied to the benefit of humankind. The founding mission
was to prevent nuclear war. While nuclear security remains a major objective of FAS today,
the organization has expanded its critical work to address urgent issues at the intersection of
science and security.
FAS publications are produced to increase the understanding of policymakers, the public,
and the press about urgent issues in science and security policy. Individual authors who may
be FAS staff or acknowledged experts from outside the institution write these reports. Thus,
these reports do not represent an FAS institutional position on policy issues. All statements
of fact and expressions of opinion contained in this and other FAS Reports are the sole
responsibility of the author or authors.
About the Author
Charles D. Ferguson is the President of the Federation of American Scientists. Prior to FAS,
Dr. Ferguson served as the Philip D. Reed Senior Fellow for Science and Technology at the
Council on Foreign Relations (CFR). Before his work at CFR, he was the Scientist-inResidence in the Monterey Institute’s Center for Nonproliferation Studies, where he cowrote (with William Potter) the book The Four Faces of Nuclear Terrorism (Routledge, 2005). He
was the lead author of the 2003 report Commercial Radioactive Sources: Surveying the Security Risks,
which was the first in-depth, post-9/11 study of the “dirty bomb” threat. This report won
the 2003 Robert S. Landauer Lecture Award from the Health Physics Society. He has served
as an adviser to the U.S. government and national laboratories. In May 2011, his book
Nuclear Energy: What Everyone Needs to Know was published by Oxford University Press. In
2013, he was elected a Fellow of the American Physical Society for his work in educating the
public and policy makers about nuclear issues. He graduated with distinction from the U.S.
Naval Academy, served in the nuclear Navy, and earned a Ph.D. in physics from Boston
University.
© 2015 by the Federation of American Scientists. All rights reserved.
For more information about FAS or publications and reports, please call 202-546-3300, email [email protected] or visit www.fas.org.
Design, layout, and edits by Allison Feldman.
Cover Photo: © franckreporter, iStock by Getty Images.
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Purposes of this Report
This report was written by a senior analyst with the Federation of American Scientists, a
non-governmental organization working to provide science-based analysis for solutions to
energy security and international security. Energy security is defined here as ensuring secure
supplies of energy sources at costs that consider economic development and environmental impact.
Understanding the impact of nuclear power on international security involves assessment of
the potential for proliferation of nuclear weapons programs.
With this wider lens of security, economic, and environmental interests, this report identifies
the major factors that will affect deployment of advanced reactors in the coming years to
decades and analyzes what industry and governments need to do to move forward toward
the ultimate goal of widespread deployment of potentially hundreds of highly energy
efficient, much safer, more proliferation-resistant, and economically competitive nuclear
power systems. Moreover, the report looks at lessons learned from the history of
development and deployment of Generation II and III reactors and seeks to learn explicitly
about the reasons for the predominant use of light water reactors. It then seeks to apply
these lessons to current efforts to develop advanced nuclear energy systems. In the process
of that assessment, the report reviews the status of the global cooperative and national
efforts to develop and eventually deploy advanced nuclear energy systems. The main
intentions of the report are to provide a guide to policymakers in the form of findings that
lay out potential pathways to forward deployment of one or more advanced nuclear power
systems within the next ten to twenty years.
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Table of Contents
Executive Summary: Up-Front Findings and Guideposts ............................................................. 4
Introduction: Advanced Nuclear Energy and Its Role in Helping Alleviate Global Climate
Problems and Energy Needs .............................................................................................................. 6
Lessons Learned from the History of Light Water Reactor Development: The Roles of
Government and Vendors, Utility Risk-Aversion, and Technological Lock-In ......................... 9
How and Why LWRs Dominated the Nuclear Power Industry in the United States ........................... 11
Concerns about Technological Lock-In ............................................................................................... 15
Lessons Learned from the Accidents at Three Mile Island and Chernobyl: The Need for
Passive and Inherent Safety Systems ............................................................................................... 17
A New Millennium and a New Era for Nuclear Power: The Creation of the Generation IV
International Forum and Its Roadmaps ......................................................................................... 19
Gas-Cooled Fast Reactor (GFR) ........................................................................................................ 21
Lead-Cooled Fast Reactor (LFR)....................................................................................................... 23
Molten Salt Reactor (MSR) ............................................................................................................... 24
Sodium-Cooled Fast Reactor (SFR).................................................................................................... 27
Supercritical-Water-Cooled Reactor (SCWR) ..................................................................................... 28
Very-High-Temperature Reactor (VHTR)......................................................................................... 29
GIF’s Working Groups .................................................................................................................... 30
Economic Modeling Working Group .................................................................................... 30
Risk and Safety Working Group.............................................................................................. 31
Proliferation Resistance and Physical Protection Working Group .................................... 31
Small is Attractive: Why there is Renewed Interest in Small, Modular Reactors ..................... 33
Regulatory Requirements for Licensing and Constructing Advanced Nuclear Energy Systems
.............................................................................................................................................................. 35
Knowledge Management, Knowledge Creation, and Training of the Workforce .................. 37
Conclusions: What Needs to be Done for Making Further Progress? ...................................... 39
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Executive Summary: Up-Front Findings and Guideposts
General Principles

Energy efficiency in all (nuclear and non-nuclear) power systems will become
increasingly important because these systems will tend to optimize use of resources
and tend to save on fuel and operating costs.

Safer nuclear plants matter for public acceptance and tend to result in better power
performance. But the layering of more and more active safety systems has tended to
drive up nuclear power plants’ costs. Consequently, shifting toward plants that do
not depend on operators’ intervention to maintain safety can offer much greater
safety at potentially lower cost. Some advanced plant designs are considered “walkaway-safe,” and some Generation III and III+ designs make significant use of
“passive” safety systems based on concepts that do not require operator activation,
such as the use of natural convection systems to circulate coolant in an emergency.

While nuclear power plants have traditionally generated constant full power, known
as base load power, newer systems that can work in load following or peaking power
modes could be more competitive especially in merchant-based utility systems in
which electricity prices can fluctuate dramatically throughout a 24-hour period, as
well as seasonally.
Role of Industry

Modular construction practices would likely result in cheaper capital costs because of
the capability to mass produce components and assemble them uniformly. In the
past, many plants have had unique design features that have driven up costs and have
impeded learning from mass production. Small modular reactors’ designs, in
particular, promise such learning and concomitant cost reductions.

Advanced nuclear energy systems that can provide services in addition to electricity
generation can offer several commercial advantages. These services include hydrogen
production for fuel cells, steam production for industrial processes, and seawater
desalination.

Newer and largely unproven fuel systems will face substantial commercial hurdles
and skepticism in the utility industry as well as face longer evaluation periods in
regulatory agencies.
Regulatory Issues

Regulatory streamlining could allow for newer plants to obtain licenses without
waiting years for the approval process. However, regulatory authorities have become
used to regulating light water reactor systems and will need sufficient time, staffing,
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and technical resources to regulate newer and more advanced systems that are
significantly different in design and concept from traditional systems.

Regulatory agencies have considerable work to do and have need of substantial
human and technical resources to prepare for licensing applications of advanced
nuclear energy systems especially those that do not use light water reactor
technologies.
Role of Governments

Government funding will be needed for the first demonstration reactors and
commercial deployments. Utilities are risk averse and will not want to spend
potentially billions of dollars on new technologies.

Small, modular reactors, which have power ratings one third or less than a typical
commercial power reactor, could help address the high capital cost hurdle because an
SMR is not expected to cost much more than a billion dollars for many of the
proposed designs. However, these systems, especially those that are different than
the light water reactors, are largely unproven, certainly at the commercial prototype
level. Thus, utilities will continue to be risk-averse in buying the first SMRs without
substantial government support. While the U.S. Department of Energy has offered
some tens of millions in such support, this might not be sufficient. A government or
governments may need to invest a few billion dollars or more to test out the first
SMRs on a commercial scale.

Bilateral and multilateral partnerships will need to be strengthened to increase the
likelihood of successful development and deployment of advanced nuclear energy
systems. Governments of major nuclear energy producing nations such as the United
States, China, France, Republic of Korea, Japan, India, Russia, and the United
Kingdom should foster these partnerships and commit adequate financial and
technical resources to these initiatives.
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Introduction: Advanced Nuclear Energy and Its Role in Helping
Alleviate Global Climate Problems and Energy Needs
According to numerous leading climate scientists, the world’s climate is undergoing humaninduced changes due to massive emissions of greenhouse gases from burning of fossil fuels
and deforestation.1 These climatic changes appear to put the planet on a collision course for
a sixth global extinction of numerous species, consequent loss of biodiversity, rising sea
levels that threaten to flood island nations and mega-cities along the coasts, and massive
effects on agriculture and the global food supply.2 Meanwhile, the global population has
recently surpassed seven billion people, and many demographers forecast more than nine
billion people by mid-century. Most of this population growth will happen in the developing
world, which by definition, is attempting to increase its economy to improve the standard of
living of its people.
This growth drives up demand for more energy resources, particularly greater access to, and
use of, electricity. According to the International Energy Agency and the World Bank, 1.2
billion people do not have access to electricity. The United Nations has set the ambitious
goal to shrink this gap to essentially zero people without electricity by 2030. The depressing
news is that the “rate of growth in electrification has still been slower than population
growth (Access to electricity grew at about 1.2 percent per year between 1990 and 2010,
while the global population grew at 1.3 percent per year.)”3 South Asia and Sub-Saharan
Africa are the two regions most lacking in electricity generation.
“Business as usual” methods will result in more than one billion people still without
electricity indefinitely into the future. Moreover, the problems of climate change will
exacerbate if business as usual trends lead to more burning of dirty fossil fuels. Coal still
remains abundant in many nations around the world, especially in China and India, the two
with the largest national populations and two of the most rapidly developing nations.
Cleaner fuel sources, such as nuclear energy and renewable energies including solar and
wind, are available but collectively fill a minority share of the globe’s electricity needs at
about 16 percent in 2014 with 12 percent from nuclear and about 4 percent from wind and
solar.4 Fossil fuel sources provided about 70 percent of the world’s electricity in 2014. (An
1
IPCC, 2014: Climate Change 2014: Synthesis Report. Contribution of Working Groups I,
II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate
Change (Core Writing Team, R.K. Pachauri and L.A. Meyer, eds.). IPCC, Geneva,
Switzerland, 151 pp.
2
See, for example, Elizabeth Kolbert, The Sixth Extinction: An Unnatural History (New York:
Henry Holt and Company, 2014).
3
Brad Plumer, “Here’s Why 1.2 Billion People Still Don’t Have Access to Electricity,”
Washington Post, May 29, 2013, which bases its reporting on the International Energy Agency
and World Bank’s assessment reports.
4
Notably, hydropower, which many people consider renewable or at least not a major
contributor to greenhouse gas emissions, supplied about 16 percent of global electricity in
2014, but social and environmental concerns about dams have severely limited the further
expansion of hydropower with many dams having to shut down although run-of-the-riverFederation of American Scientists
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operating nuclear power plant does not emit greenhouse gases, and solar and wind electricity
sources do not either, although the entire life cycle of nuclear, solar, and wind energy
systems do generate relatively small portions of such emissions but at much lower rates than
fossil fuel energy systems.) To generate enough power for the more than one billion people
lacking electricity and to displace coal and other fossil fuels where electricity is being
generated, nuclear, solar, and wind energy systems need to be deployed at a much greater
scale.
While solar and wind energy systems will play larger roles in the coming years to decades,
this report examines the near (up to ten years) to long term (ten to thirty years) roles for
advanced nuclear energy systems because of the huge energy density available from nuclear
energy that can be especially well suited to providing massive amounts of cleaner energy to
urban dwellers. As of 2014, a majority of the world’s population lives in cities, and the
relative proportion of city dwellers is expected to outpace rural residents in the coming
decades. Although people in cities can and generally do use renewable energy systems,
people in high-rise apartment buildings, for example, would have difficulty in having their
own solar panels or wind turbines.5 Most electrical power would be distributed to these
people from power plants outside the cities. While these plants could include concentrated
solar thermal plants and wind farms stretching over hundreds of miles, nuclear power plants
could provide reliable power for all weather conditions around the clock while still having a
much smaller “footprint” in land area use as compared to renewable energy sources.
But can nuclear power take the leap from about 12 percent of the world’s current electricity
generation to a much larger share? To make a greater contribution to the globe’s energy
supply, nuclear energy will have to be financially competitive while also providing reliable
and safe means of electrical power. As discussed in this report, the economic experience has,
at best, had mixed results for the costs of nuclear power plants. In general, the capital costs
for construction have been high while the operating and fuel costs have been comparatively
low, as compared to coal-power plants. The relatively cheap prices in recent years for natural
gas in the United States, for example, have further made nuclear power appear economically
uncompetitive in many regions. But natural gas will not last forever; shortages may be
experienced in the coming decades based on demands placed on this fossil fuel. Also, the
low prices are not guaranteed to stay low.
Presently, almost all operating nuclear power plants are generally referred to as Generation II
designs, which came from developments in the late 1950s to the 1970s and were mostly built
until the late 1980s. Generation II designs are typically of two types: pressurized water reactors
(PWRs) and boiling water reactors (BWRs), which both use light water, or H2O, to moderate
neutrons to keep the nuclear chain reaction going and to cool the reactor core. The LWRs
usually have energy efficiencies of about 33 percent in conversion of the reactor’s heat to
useful electricity.
hydro power is typically more environmentally friendly but may not generate as much
electricity as large dams.
5
For example, the author has solar panels on his row house in Washington, DC, to provide
about half of his home’s electricity on average annually, and still makes use of nuclear
generated electricity from the Calvert Cliffs Nuclear Power Plant in nearby Calvert County,
Maryland.
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In the past twenty to twenty-five years, Generation III and III+ designs have started to be
developed and deployed. These systems are evolutionary designs to improve primarily on the
Generation II LWRs with added safety features but are usually not much improved in terms of
energy efficiency. Advanced nuclear energy systems are mostly considered to be so-called
Generation IV designs, which were first classified as such around the year 2000 (as described
later in this report). Many Generation IV designs have their roots in the 1950s and 1960s, as
this report will describe. Several of the Generation IV designs are significantly different in
concept than Generation II, III, and III+ and typically have much greater energy efficiencies of
about 40 to 50 percent. Technological improvements in recent years and the near to
intermediate future could make some of these Generation IV designs commercially viable in
the not too distant future. But they will have to compete with the currently available
Generation III and III+ designs as well as the relatively cheap coal-fired and natural gas-fired
power plants.
Being more energy efficient than presently operating nuclear power reactors, advanced
nuclear energy technologies hold tremendous potential to make much further contributions
to help solve the world’s energy needs and help reduce the emissions of greenhouse gases to
the atmosphere. While many countries have demonstrated significant progress on research
and development, several financial roadblocks have impeded full deployment of these
technologies. The real test is the commercial market. As underscored by Dr. Andrew
Sowder, senior technical leader at the Electric Power Research Institute (EPRI), “It is great
to develop a technology, but it’s really not commercially viable unless you can license it and
someone can provide the money to finance it.”6 [EPRI is a nonprofit organization focused
on providing near and long term solutions for the electric power industry and the industry’s
customers.]
6
“ANS Winter Meeting, Nuclear: The Foundation of Clean Energy,” Nuclear News, January
2015, p.67.
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Lessons Learned from the History of Light Water Reactor Development:
The Roles of Government and Vendors, Utility Risk-Aversion, and
Technological Lock-In
This section takes a brief but relatively in-depth look at the history of nuclear power to glean
lessons relevant for the future development of advanced nuclear power systems. In the late
1940s, after the Second World War, peaceful nuclear power was in its infancy. The
Manhattan Project harnessed nuclear energy for the purposes of making nuclear weapons,
and this also led to early work on the first types of nuclear reactors. However, these reactors
were geared toward production of weapons-grade plutonium and not for electricity
generation.
By the end of the war, leading nuclear scientists were already starting to think about and plan
for the peaceful applications of nuclear power. Because available data at that time indicated
that uranium resources were scarce, these experts believed that nuclear power’s viability
required breeder reactors. Breeder reactors create more fissile material than they consume by
using the excess neutrons from fission to breed more fissile material from fertile material.
For example, fission of a fissile uranium-235 nucleus creates more than two, but not more
than three, neutrons. One of the neutrons is used to further fission with another uranium235 nucleus while the excess neutrons can be absorbed by uranium-238 nuclei, which are
also fertile. After two radioactive decays, the material is transformed into plutonium-239, a
fissile material. Thus, more plutonium-239 can be produced than the uranium-235 that
underwent fission. This plutonium-239 can be recycled into new fuel for reactors. The
important point here is that from the early days of nuclear energy development, leading
scientists were working on designs for breeder reactors on the assumption that this was
needed to make nuclear energy viable for decades to come.
In a parallel effort in the late 1940s and into the early 1950s, the United States launched a
program to make nuclear reactors suitable for submarines. Submarines are relatively compact
warships designed to dive hundreds of meters under the surface of the seas and to withstand
intense shocks from underwater explosions. The Navy wanted to deploy submarines for
months at a time without the need for refueling. These boats had to be quiet and stealthy in
order to reduce the likelihood of detection from an enemy’s anti-submarine warfare
techniques. Thus, nuclear reactors for submarine propulsion had to be rugged, quiet, fit in
small compartments, and reliable over many years (and ideally decades). Then-Captain and
later Admiral Hyman Rickover became the leader of the naval nuclear propulsion program.
He and his team of engineers had studied many different reactor designs at Oak Ridge
National Laboratory as well as had sought advice at other prominent U.S. laboratories. He
was famous for stating that he learned from studying technologies where one should not
choose the very “best” technology because that would be too risky, especially for such a
demanding environment as undersea warfare. However, he also was very reluctant to choose
the “second best” technology. Instead, he chose what some would have considered the
“third best” technology: light water reactor technology. It might be deemed “third best”
because it was not very energy efficient but still efficient enough at around 33 percent for
modern light water reactors.7 It was also not suitable, or at least optimal, for breeding new
7
Norman Polmar, Rickover: Father of the Nuclear Navy (Potomac Books, 2007).
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fissile material, although light water reactors using low enriched uranium fuel do derive
much of their energy over their operating life from producing and fissioning plutonium.
The advantages of light water reactors were apparent for seagoing vessels and for a navy that
had considerable experience with steam-powered boilers. One advantage was that the
relatively low efficiency reactors had a ready heat sink in the surrounding sea. The U.S. Navy
also had access to a growing stockpile of highly-enriched uranium (HEU) as a by-product of
the nuclear weapons program. Giant gaseous diffusion plants were used to enrich many
hundreds of metric tons of HEU. HEU is very energy dense and the Navy eventually used
reactors designed for weapons-grade uranium with more than 90 percent enriched in
uranium-235.
While Rickover had the Office of Naval Reactors design and build two sodium-cooled
reactors, the S1G followed by the S2G, he was very dissatisfied with that reactor because of
the difficulty in operating it and the concerns about the reactivity of liquid sodium with air
and water. This experience further solidified Rickover’s decision to stick with the simpler
system of a pressurized water reactor. Liquid water under high pressure has good heat
transfer properties and can be relatively easy to use in generating steam for propulsion in
turning the propeller of the submarine and creating electricity in the turning of the turbines
used to operate the electric generator. Consequently, because of the U.S. Navy’s
determination to have a nuclear-powered submarine by the mid-1950s, PWR technology
received a significant “head start” in operational experience over several other competing
designs (although R&D continued on other designs such as gas cooled reactors and molten
salt reactors).
LWRs gained another major boost as a result of President Dwight Eisenhower’s Atoms for
Peace initiative, launched in December 1953. The United States sought to win the upper
hand in the “peace” race with the Soviet Union by showing the world that U.S. nuclear
technologies were not just for weapons or for other military purposes, but could, and would,
improve the quality of life for humanity through applications of nuclear energy to
agriculture, medicine, and electricity generation. In the latter area, the United States needed
to urgently showcase a commercial power reactor. Because of the lead development of the
PWR, it was chosen as the first major commercial development project at Shippingport,
Pennsylvania, although early research at some national laboratories had shown the potential
promise of alternative reactor technologies. The United States also moved quickly to change
its federal law via the 1954 Atomic Energy Act to allow sharing of “atomic energies” with
other countries through peaceful nuclear energy cooperation agreements. This led to many
client states receiving research reactors and subsequent support for power reactor
development. These power reactors mostly used LWR technology (with some exceptions
being pressurized heavy water reactors (PHWRs) or CANDUs developed and exported by
Canada).
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How and Why LWRs Dominated the Nuclear Power Industry in the United States
In 1977, the RAND Corporation published the findings of a comprehensive study of why
LWRs seized such a strong hold on the nuclear power industry.8 The authors cautioned that
the history is not neat and simple; there are overlapping themes, issues, and factors. They
underscored that there is not a “nuclear industry” as such: “The phrase encompasses an
amalgam of risk-averse utilities, scientists and engineers dedicated to advancing the state of
the nuclear technology, regulatory bodies concerned with the cost of electricity to the
consumer, plant operators impatient of demands for ever more extensive safety precautions,
and interveners convinced that catastrophe is imminent, reactor manufacturers concerned
with their sales prospects, and major or minor participants in abundance with roles that
extend from extracting uranium to keeping an existing plant ‘on line’ at all possible times.”9
Notably, the U.S. national goal for nuclear energy since 1953 was to make it cost competitive
with electricity generated by the burning of fossil fuels, in particular, coal-fired power plants.
In 1977, when the RAND researchers were writing their report, it was highly uncertain
whether nuclear power plants could compete economically with fossil fuel power plants even
with an upward trend in fossil fuel prices between 1967 and 1977. High construction costs
and continual changes in safety regulations were two major contributing factors.
In the RAND report’s findings, the analysts pointed out that “more than five principal
avenues to commercially competitive nuclear power seemed open in the early 1950s, but 20
years later the LWR was the only healthy survivor.” In the late 1950s, the Atomic Energy
Commission (AEC) sponsored a comprehensive Power Reactor Development Program in
order to not rely on one particular technology and allow for evaluating different design
concepts for commercial viability. But as the RAND report notes, some critics have
complained that the AEC may have pulled R&D support prematurely from some of these
alternative technologies, most notably the high temperature gas reactor (HTGR), which
proponents have emphasized to be safer and more energy efficient than the LWR. Another
critique is that the AEC “elected to solicit the support of small utilities for reactor
technologies far riskier than the LWR” and that these utilities did not have adequate financial
wherewithal to risk on these alternatives. In contrast, the LWRs’ “head start” enabled them
to demonstrate their reliability in a relatively brief period of the late 1950s to early 1960s.
Nonetheless, utilities were not willing to gamble on LWRs without subsidies from
government or vendors.
Government, mostly via the AEC, provided large subsidies in the late 1950s and into the
early 1960s. But “the utilities remained fearful that unless privately funded commercial-scale
nuclear plants were built, the government might in the end decide to fund something on the
order of a nuclear TVA.” TVA, or the Tennessee Valley Authority, was founded in 1933
during the Great Depression as a massive public works program that the federal government
funded and owned in order to provide electricity, flood control, navigation, and economic
development to the Tennessee Valley region of the southern United States, an area hit hard
by the Great Depression. After the Great Depression, executives of U.S. utilities wanted
8
Robert Perry et al., “Development and Commercialization of the Light Water Reactor,
1946-1976,” R-2180-NSF, RAND, June 1977.
9
Ibid, p. vi.
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much less or even no government involvement or ownership in their businesses. But to
make nuclear power plants cost-competitive with fossil fuel plants, their capital costs would
have to be kept comparable to coal-fired plants. However, with only a few governmentsubsidized nuclear plants as a guide, it was highly uncertain that nuclear plants could
compete in the unsubsidized market.
The financial innovation was for vendors to offer “turnkey plants,” meaning the companies
building the plants would guarantee a fixed price and would have to pay for any cost
increases that might occur during construction. Only two companies, Westinghouse and
General Electric, had the financial depth at that time to risk making this offer. While the
total amount of losses were not reported by these companies, both lost an estimated more
than $1 billion over a several year period on these nuclear construction projects that they
started in the 1960s. The RAND report noted that there was “unrealistic expectations of
cost competitiveness” as compared to fossil fuel-fired plants. Why did this occur? Aside
from the fact that nuclear power plants were in their infancy, vendors believed that “large
nuclear plants were merely enlarged copies of the smaller plants with which the industry had
all its pre-1960 experience.”10 Another misconception was that the nuclear power plants
could be built in a similar fashion as coal-fired power plants and that the “nuclear heat
source could be treated as a variant of a conventional steam generator. This proved to be far
from the case. The consequences were vastly greater construction costs than had been
expected and considerable delays in plant construction.” Among the technical reasons why,
“requirements for precision fitting and for fail-free equipment were considerably more
demanding for nuclear installations than for older fossil-fuel plants, and the difficulties of
satisfying demands for high safety standards accounted for many of the cost and schedule
overruns that marked the 1970s.”11
By 1963, some utility executives thought they could order non-turnkey plants because they
believed that if their companies had control over contracting and scheduling, the costs could
be much better contained. However, they too experienced major cost overruns and
construction delays. Both turnkey and non-turnkey plants suffered from significant
estimating errors for the costs. The financial losses could have dealt an irreparable blow to a
nascent industry given the opposition by the mid-1960s at GE and Westinghouse to
continue to offer turnkey contracts. Instead, they increased their bid prices. Nonetheless,
some utilities persisted in investing in nuclear plants after the mid-1960s although they were
experiencing significant cost increases.
The mounting financial costs might have halted further construction if other elements of
world finances had not changed and made nuclear power still look somewhat competitive.
Namely, coal prices increased after 1965. Moreover, the burgeoning environmental
movement in the United States became increasingly alarmed by how burning of coal resulted
in harmful health effects. By the early 1970s, this movement resulted in the passage of the
National Environmental Policy Act and the creation of the Environmental Protection
Agency. Regulatory rule changes required coal plants to make design changes to cut down on
emissions of harmful substances such as mercury and heavy metals. By the 1980s, the focus
would turn to sulfur dioxide and nitrous oxide, chemical compounds that result in harmful
10
11
Ibid, p. 83.
Ibid, p. 83.
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acid rain. Today, the focus of EPA rule changes is on limiting emissions of greenhouse gases
especially carbon dioxide. But during the 1970s, the new regulations favored nuclear power
plants because coal-fired plants had to increase costs to pay for emission control
technologies.
Examining whether the power rating size of a nuclear plant made a significant difference, the
RAND study found that even with fossil-fuel plants in the late 1950s and 1960s there was no
experience in building a power plant bigger than 750 MWe. Despite this lack of experience,
“the constructors, designers, and buyers set out to build plants ranging from 400 to 850
MWe, and 1000 MWe plants were designed and ordered two years before any installations
larger than Dresden (200 MWe) had become operational. In the rush to obtain returns to
scale, the industry ignored (or perhaps never noticed) the importance of sequential learning
exhibited by the progress of early LWR development. Larger plants were more difficult to
build, had (contrary to expectation) lower reliability, and generated more costly (or not much
cheaper) electricity than the less ambitious plants of the period.”12 This finding is relevant to
today’s shift toward considering small, modular reactors (SMRs) as a means to reduce financial
risk and to build modularly designed plants that can potentially achieve economies of scale
unlike the experience of and trend toward much larger nuclear power plants. This report
discusses SMRs in more depth later.
In summing up the findings from the period 1946 to 1976, the RAND researchers outlined
the successful elements of the LWRs’ research, development, and deployment:
12

From 1948-1953, there was early evaluation of the practical applicability of the LWR
concepts.

Also during that period, the Navy’s reactors program and other smaller scale tests
resulted in greater understanding of critical components and processes for PWRs.

Soon after 1953, there was a national commitment to and follow-through toward a
“prototype” commercial program as exemplified by the Shippingport reactor.

This led to larger scale testing of the central elements of the PWR in a semioperational setting that had commercial applications, for example, the Yankee
Nuclear Power Station.

Notably, sequential development and demonstration, with some overlap, permitted
the results of one experiment to be evaluated and applied to the next in the series.

One of the major principles was conservatism in design and engineering concepts
during test and demonstration.

Government subsidies played a substantial role at the beginning and intermediate
phases of development and demonstration and gradually decreased as the scale of
demonstration and construction grew larger.
Ibid, p. 84.
Federation of American Scientists
|13

Finally, government decreased, and eventually stopped, its direct involvement in
paying for plant construction as dependence on manufacturers for technical
advances increased.13
The RAND study also identified several caveats and problems:

The AEC was insensitive “to the complex, non-political, institutional elements of the
demonstration process” such as the “inappropriate coupling of high-risk
demonstration plants with financially constrained small utilities.”

The government reduced “R&D support, particularly for the safety elements of the
light water reactor.”

The AEC discontinued “the demonstration program while some promising (design
and fuel) cycles still were incompletely developed” such as the HTGR.

As mentioned earlier, vendors and utilities had “unrealistic expectations of cost
competitiveness before other than ‘small’ non-representative plants had been
demonstrated.”

The AEC was reluctant “to accept responsibility for any effects of nuclear plant
construction other than those involving nuclear safety (before 1971).”

Government showed “indifference to the increasing public concern for safety … and
environmental effects.”

Government and industry had “excessive confidence in the predictability of the
future and prospects for LWRs.” They were predicting the demand by the year 2000
for more than ten times the number of LWRs than were eventually constructed and
operated. [U.S. electricity demand and growth in the 1980s and beyond was far less
than the near exponential growth that was forecasted in the 1960s and 1970s.]

Finally, the AEC emphasized “reactor development without adequately addressing
other elements of the nuclear cycle (enrichment, reprocessing, and waste
management).”14
Based on these adverse experiences, or at the very least, cautionary tales, the RAND
researchers assessed that there would be “some unexpected consequences for the future of
other nuclear (and non-nuclear) options:

13
14
Neither utilities nor manufacturers are likely to make major commitments to
potentially high cost systems or concepts that have not been demonstrated at nearly
full scale.
Ibid, pp. 84-85.
Ibid, pp. 85-86.
Federation of American Scientists
|14

Government subsidies of promising new approaches probably will have to be
continued farther into the test, demonstration, and proof of commercial feasibility
cycle than was the case for LWRs.”15
It is also worth underscoring the general recommendations of the RAND report because of
the relevancy for future advanced nuclear and non-nuclear energy systems:

“Cost estimating accuracy is an essential aspect of successful commercialization; the
development of appropriate costing methodologies should be emphasized in all
future planning.

Analyses of future energy requirements should include consideration of alternative
futures, and programs should provide specifically for adjusting investments and goals
to adapt to sudden or major changes in demand, price, or technology.

Institutionally generated pressures for continued support of some special
technologies should be discounted in evaluating the need for and feasibility of
various approaches; functional rather than institutional budgeting may be most
appropriate for technologies approaching the commercialization phase.

The development of a complex technological system requires balanced effort in all of
its principal elements.”16
Concerns about Technological Lock-In
The question remains: Has the nuclear industry experienced technological lock-in in which
one technology predominates yet is not the optimum solution? There have been many
examples in history of this paradigm.17 For instance, some would argue that Microsoft’s
dominance with Windows operating systems for personal computers and its suite of Word
software have provided decent (but not the best) solutions. However, the “best” or
seemingly optimal solution might be considered too risky in terms of financial cost,
technological complexity, or other features that could impede widespread consumer
adoption of the technology. The real test for non-LWR technologies will be whether they
can make in-roads into the commercial marketplace given the nearly 60 years of commercial
experience with LWRs.
Another likely barrier to more advanced nuclear energy systems is the potential technological
lock-in of uranium dioxide fuels, especially those in a once-through fuel cycle or mixed oxide
fuel in once-recycle fuel cycle. That is, a fully-closed fuel cycle has not been implemented
commercially in the world. (While France and Russia, for example, might seem to have
closed the fuel cycle, in reality they do a once-through recycling of plutonium from irradiated
fuel. The irradiated fuel from that recycling has been stored pending potential further
15
Ibid, p. 86.
Ibid, p. 87.
17
Richard Perkins, “Technological ‘lock-in’,” International Society for Ecological
Economics, Internet Encyclopaedia of Ecological Economics, February 2003.
16
Federation of American Scientists
|15
deployment of reactors that can consume the remaining fissionable materials and thus fully
close the fuel cycle.) Higher costs have held back such development as well as concerns
about proliferation arising from use of breeder reactors although fast neutron reactors in a
“burner” mode might help address these concerns. Moreover, the relative abundance of
natural uranium given the present and foreseeable demand for nuclear power has also
impeded a closed fuel cycle from being developed. Nonetheless, with certain countries such
as France and Korea wanting to develop such fuel cycles for waste management reasons, it is
worth pondering whether the existing fuel system could further impede progress because of
technological and political inertia. Of course, before implementing, closed fuel cycles must
meet nonproliferation standards and should be cost-competitive. But the cost competiveness
evaluation would need to factor in a holistic systems approach, namely the potential benefits
of external costs from better waste management and countries’ evaluations of energy
security.
The thorium-fuel system appears also to have fallen victim to technological lock-in. Thorium
is not fissile alone but instead is fertile and can be transmuted into fissile uranium-233 after
two radioactive decays. Thorium is estimated to be three to four times more abundant than
natural uranium, and thus could in principle provide several hundred years of energy
supplies. In addition, thorium fuel cycles appear to offer enhanced proliferation resistance
because of the production of uranium-232, which is relatively high in radioactivity and would
complicate the use of uranium-233 in nuclear weapons. However, the thorium fuel cycle is
not “proliferation proof” because it is possible to separate out nearly pure uranium-233 and
even the presence of uranium-232 might not stop determined use of uranium-233 in an
improvised nuclear explosive device.18 But the large amounts of thorium required and the
extra expense would likely make this method prohibitive or at least not nearly as desirable as
more traditional methods of producing weapons-grade plutonium. While there are groups
advocating for the use of thorium as nuclear fuel, little has been done to reach
commercialization (although this report later discusses the Generation IV International
Forum’s and others’ work on reactor systems that could use thorium). It is telling that
Thorium Power, a company founded about 20 years ago to commercialize thorium fuels has,
in recent years, rebranded itself as Lightbridge Corporation and has been earning its revenue
by providing advisory and other services for the uranium fuel market and light water reactor
technologies as well as making progress in developing advanced metallic uranium-based
fuels.19 It is worth keeping in mind the principles of technological lock-in and inertia when
considering the barriers that non-LWR and non-uranium fuels would have to overcome.
18
Stephen F. Ashley, Geoffrey T. Parks, William J. Nuttall, Colin Boxall, and Robin W.
Grimes, “Nuclear Energy: Thorium has risks,” Nature, vol. 492, December 6, 2012, pp. 3133.
19
See press releases of Lightbridge Company at http://ir.ltbridge.com/releases.cfm, accessed
on May 31, 2015.
Federation of American Scientists
|16
Lessons Learned from the Accidents at Three Mile Island and
Chernobyl: The Need for Passive and Inherent Safety Systems
Before 2011, there had been only two major nuclear power accidents in the world. In 1979,
one of the reactors at the Three Mile Island (TMI) Nuclear Power Plant in Pennsylvania
experienced a partial fuel meltdown. Fortunately, the containment structure remained intact
and thus the public was not exposed to significant radioactivity from the accident (although
the governor of Pennsylvania did order pregnant women and young children to evacuate as a
precaution). The TMI reactor was a pressurized water reactor.
A much worse accident happened seven years later at the Chernobyl Nuclear Power Station
in Ukraine when the operators placed one of the reactors into an unsafe operating mode,
ironically during a test of safety systems. The reactor was an RBMK, or graphite-moderated,
water-cooled reactor, with design flaws that became apparent when the operators took
actions to place the reactor in an unusual condition that then led to the accident. One major
flaw was that when the control rods were inserted, the reactivity initially increased because
the ends of the rods were made of graphite, which moderated the neutrons and thus spiked
reactivity. The accident resulted in a steam and hydrogen gas explosion that blew the top off
the roof of the reactor building. This power plant did not use a strong containment system
(unlike TMI). Massive amounts of radioactive contamination spread widely across Europe.
This contamination triggered alarm in many European countries and contributed to
numerous people in several countries expressing opposition to nuclear power. Thus, by
1990, the outlook for nuclear power in much of Europe looked unpromising. Something had
to change to make nuclear power acceptable again.
According to a major study in 1991 by Charles Forsberg and William Reich at Oak Ridge
National Laboratory, “The key characteristic of the TMI and Chernobyl accidents was that
the operators shut down functional safety systems for what seemed to be good reasons at
the time. If those safety systems had remained operational, the accidents would not have
occurred. These were accidents of commission—deliberate actions by operators—not
equipment failures or failure to follow instructions. The solution proposed to eliminate these
and other safety issues is the use of passive and inherent safety. It is a radical change in
technology. Whether it will be a technical, economical, and institutional solution to solve the
problems associated with nuclear power is unknown.”20
This was one of the first major reports to emphasize a shift in passive safety systems that
could even be considered inherently safe (although one could not rule out operators still
trying to intervene incorrectly). The analysis in Forsberg and Reich’s report was illuminating.
They defined the acronym PRIME to signal their proposed “radical” change. PRIME stood
for “Passive safety, Resilient safety, Inherent safety, Malevolence resistance, and Extended
time for external aid after an accident.”
20
Charles W. Forsberg and William J. Reich, “Worldwide Advanced Nuclear Power Reactors
with Passive and Inherent Safety: What, Why, How, and Who,” Oak Ridge National
Laboratory, ORNL/TM-11907, Prepared for the U.S. Department of Energy, September
1991.
Federation of American Scientists
|17
Forsberg and Reich underscored passive safety throughout their report because of the past
history of nuclear power accidents. They also examined economics primarily through the
lens of safety. For instance, their report cites studies that show that “30 to 60% of the cost
of nuclear power is related to health, safety, and environment. This implies that if major
improvements in economics are to be obtained, new approaches to safety are required. The
cost of active safety systems is a major factor in the cost of nuclear power.”21 They also
highlighted the cost of money in making investments and how investors became wary in
spending their money on nuclear power given the perception of safety concerns following
the accidents. It is also interesting to note that they drew attention to the “greenhouse
effect” and how this might help make the case for further expansion of nuclear power. But
they also cautioned that it is challenging for nuclear power “to be used on a large scale in
underdeveloped countries” with “increased concerns about the low skill levels, political
instabilities, and limited resources applied to safety. These factors may increase accident
probabilities if passive and inherent safety technologies are not used.”22 All the issues they
raised in 1991 are still relevant today and have influenced the designs of many of the
proposed advanced nuclear energy systems considered in the following section.
21
22
Ibid, p. 6.
Ibid, p. 7.
Federation of American Scientists
|18
A New Millennium and a New Era for Nuclear Power: The Creation of
the Generation IV International Forum and Its Roadmaps
During the 1990s, nuclear power plant construction stagnated around the world. While there
was continued significant construction efforts in a few countries, notably Korea, most of the
major nuclear power producing countries had all but stopped the building of reactors.
During that time in particular, the United States had not ordered a new plant since the TMI
accident and had cancelled many orders for plants. France and Japan experienced a major
upsurge in construction during the 1980s which then declined in the 1990s having mostly
reached their nuclear energy generation goals. As mentioned in the previous section, this
major downturn was in most of Europe in response to the Chernobyl accident. Voters in
several countries passed referenda that resulted in government policies to phase out, or at
least not expand use of, nuclear power.
Even with a plateau in nuclear power plant construction, several countries still moved
forward with research and development of advanced reactor designs. Korea, for example,
explored a technology known as DUPIC that would reuse uranium and could burn up
transuranic elements in pressurized heavy water reactors in order to better manage and
reduce the volume of nuclear waste needing to be stored.23 The Korea Atomic Energy
Research Institute (KAERI) also developed small modular reactor designs such as SMART,
which has now reached the point where it can take the next steps for commercial
development. In addition, KAERI examined other proliferation-resistant methods for
advanced nuclear energy systems, such as using pyroprocessing to make mixtures of
transuranic and fission product material for eventual consumption in fast neutron reactors
(including sodium-cooled fast systems). The United States has continued its R&D efforts at
various national laboratories such as Argonne, Idaho, Oak Ridge, and Los Alamos. The
Argonne National Laboratory, in particular, devoted significant work on the integral fast
reactor combined with pyroprocessing. The funding, however, was suddenly cut during the
Clinton administration in 1994. U.S. nuclear R&D largely shifted during that period toward
light water reactor systems, which were considered well proven and well entrenched.
Additional R&D took place in Japan, Russia, and the European Union. While a
comprehensive list of these activities is beyond the scope of this report, this report does
recognize that these R&D activities formed the basis for a more formalized and multinationally cooperative approach to advanced nuclear energy systems.
In January 2000, under the auspices of the Nuclear Energy Agency (NEA) of the
Organization for Economic Cooperation and Development (OECD), headquartered in
Paris, France, several countries undergoing the aforementioned R&D activities and others
wanting to further these activities came together to form the Generation IV International
Forum (GIF). GIF, in addition, received substantial resource and staffing support from the
U.S. Department of Energy’s Nuclear Energy Research Advisory Committee (NERAC). U.S.
23
For example, see: A. C. Morreale, W. J. Garland, and D. R. Novog, “The Reactor Physics
Characteristics of a Transuranic Mixed Oxide Fuel in a Heavy Water Moderated Reactor,”
Nuclear Engineering and Design, Vol. 241, Issue 9, September 2011, pp. 3768-3776, shows
simulations that indicate substantial consumption of transuranic material when formed into a
mixed oxide fuel in a PHWR computer model.
Federation of American Scientists
|19
lead representative William Magwood IV became the first chairman of GIF. (He is now the
head of the NEA.) The GIF Charter, officially established in July 2001, was initially
comprised of nine founding members and has subsequently expanded to 13 members:
Argentina, Brazil, Canada, China, Euratom, France, Japan, the Republic of Korea, the
Russian Federation, South Africa, Switzerland, the United Kingdom, and the United States.
In 2002, GIF published a technology roadmap with four main goals to achieve the fourth
generation of nuclear power systems:
I.
II.
“Sustainability
 Generate energy sustainably and promote long-term availability of nuclear
fuel.
 Minimize nuclear waste and reduce the long-term stewardship burden.
Safety and reliability
 Excel in safety and reliability.
 Have a very low likelihood and degree of reactor core damage.
 Eliminate the need for offsite emergency response.
III.
Economic competitiveness
 Have a life cycle cost advantage over other energy sources.
 Have a level of financial risk comparable to other energy projects.
IV.
Proliferation resistance and physical protection
 Be a very unattractive route for diversion or theft of weapon-usable
materials, and provide increased physical protection against acts of
terrorism.”24
This roadmap also described the necessary R&D to accomplish full deployment of these
systems after 2030. The systems included the nuclear reactors, the energy conversion
systems, and the fuel cycles. Interested readers are advised to visit the GIF website for the
full report.25 Here, this report provides an overview of the six nuclear energy systems
selected for inclusion in GIF.
The selection process winnowed from almost 100 different design concepts to only six. GIF,
however, does not want to suggest that these six would be the only viable future nuclear
energy systems. Moreover, these six designs can involve various modes of operation and
different fuel systems and thus can, in effect, be considered to be more than just six designs.
Notwithstanding, these six were deemed to be far enough along, based on previous R&D
and some operating experience, for several types of these systems. These six designs also
represent a mix of evolutionary systems following the current light water reactor systems to
many revolutionary energy systems, departing significantly from almost all presently
operating commercial reactors (except for a few sodium-cooled fast reactors in use in Russia
24
GIF Roadmap report, January 2014, pp. 14-15.
The full report, A Technology Roadmap for Generation IV Nuclear Energy Systems, GIF002-00, 2002, is available at www.gen-4.org.
25
Federation of American Scientists
|20
and India and in development in Korea, Japan, and France). For a detailed description of the
reactor systems as well as the latest GIF roadmap for next important steps for each system,
readers can access the January 2014 GIF report;26 here, the main features and urgent R&D
needs of each system are noted as a guide to the findings of this report. To prove
commercial viability, each nuclear energy system will have to undergo extensive work in
three successive phases:
I.
“The viability phase, when basic concepts are tested under relevant conditions and all
potential technical show-stoppers are identified and resolved;
II.
The performance phase, when engineering-scale processes, phenomena, and
materials capabilities are verified and optimized under prototypical conditions; and
III.
The demonstration phase, when detailed design is completed and licensing,
construction, and operation of the system are carried out with the aim of bringing it
to the commercial deployment stage.”27
Before describing the specific designs, it is worth underscoring some general features that are
common to all (or most of) these designs. First, all of these designs offer significantly higher
energy efficiencies than the presently operating thermal reactors, including all light water
reactors and heavy water reactors. Typically, it is estimated that the six GIF designs could
provide efficiencies from 40 to almost 50 percent in comparison to the usual 33 to 34
percent for thermal reactors while some power up-ratings have boosted light water reactors
up to 36 percent. Higher energy efficiency means more electrical energy and other useful
energy such as hydrogen fuel production per unit of heat energy in the reactor core and thus
less wasted heat energy that would be released into the environment. Higher efficiencies
would help in saving fuel costs and could help make advanced nuclear energy systems more
competitive with fossil fuel energy systems. (For example, combined cycle natural gas power
plants can achieve 50 to 60 percent efficiencies.) The GIF designs achieve higher efficiencies
primarily via higher operational temperatures. Several of these designs can also use highly
efficient Brayton power cycles in comparison to the steam Rankine cycle of today’s thermal
reactors.28 The GIF designs, in addition, have higher reactor power densities. Moreover,
several of the designs envision on-site integrated, or close-proximity, means for processing
and recycling spent fuel, resulting in better waste management.
Gas-Cooled Fast Reactor (GFR)
The GFR uses helium for cooling of, and heat transfer from, the reactor core, which is a fast
neutron reactor. It is envisioned that the GFR will have a closed fuel cycle with multiple
recycling functions to consume long-lived actinides for waste minimization. One advantage
26
See: Generation IV International Forum, Technology Roadmap Update for Generation IV
Nuclear Energy Systems, Issued by the OECD Nuclear Energy Agency, January 2004.
27
GIF Roadmap report, p. 8.
28
See, for example, the following website for an accessible technical explanation of the
Brayton cycle:
http://web.mit.edu/16.unified/www/SPRING/propulsion/notes/node27.html, accessed
on May 31, 2015.
Federation of American Scientists
|21
of the GFR is that helium is chemically inert and would not have corrosion or radiotoxicity
problems as compared to other high temperature systems. Notably, GFRs could provide
very high thermal efficiencies of about 48 percent. General Atomics has claimed that its
EM2 GFR design might even reach 53 percent thermal efficiency.29
Granted, with the use of GFR, there are significant challenges associated with such high
temperatures, as well as other demanding operational conditions. Because of the low thermal
inertia, the core could experience rapid heating in the event of loss of forced cooling, which
could potentially result in a meltdown. This loss of forced cooling could happen through
depressurization. Moreover, because the power density is high, conduction cool-down will
not function as it would for other types of high temperature gas-cooled reactors (HTGRs).
In addition, the helium density is too low to provide sufficient natural convection for core
cooling. Furthermore, research is needed to address the effects of fast neutron
bombardment on the pressure vessel. In contrast, other traditional HTGR systems use
graphite moderation that will slow down the neutrons and thus mitigate the neutron
bombardment on the pressure vessels.
The GIF Roadmap emphasizes that there remains a need “for a small experimental reactor
to be available within the next 10-20 years. The ALLEGRO experimental reactor project
currently being undertaken by a consortium of four countries (the Czech Republic, Hungary,
Poland, and the Slovak Republic) fulfils this requirement. ALLEGRO will be the first fast
spectrum gas-cooled reactor to be constructed and will be the test bed to develop and qualify
the high-temperature, high-power density fuel that is required for a commercial scale hightemperature GFR.”30 This reactor will be around one-tenth of the power rating of a full-scale
GFR.
Another critical need is creation of an acceptable fuel system. In particular, a cladding
material for the fuel that meets core specifications, including leak tightness, ductility,
compatibility with helium that could have impurities, and the intense radiation conditions, is
needed. The GIF Roadmap specifies criteria of:

“Clad temperature of 1,000o C, during normal operation;

No fission product release for a clad temperature of 1,600o C during a few hours; and

Maintaining the core-cooling capability up to a clad temperature of 2,000o C.”31
The fuel development will require international collaboration, as no specific country has the
requisite expertise for this system. GIF recognizes that this system will need considerable
R&D effort to move it to a commercial consideration stage. First, over the next 10-20 years,
the design of the small experimental reactor will have to be finalized, and then the decision
will have to be made about the licensing process for the experimental reactor. Perhaps by
29
See http://www.ga.com/websites/ga/docs/em2/pdf/FactSheet_QuickFactsEM2.pdf,
accessed on May 31, 2015.
30
GIF Roadmap, 2014, pp. 20-21.
31
Ibid, p. 21.
Federation of American Scientists
|22
2025, this reactor will reach the performance demonstration phase. The GIF Roadmap does
not project out beyond 20 years and thus does not anticipate a commercial prototype within
that time period.
In a recent independent study of the prospects for advanced nuclear energy systems, the
Breakthrough Institute, a non-governmental organization based in Oakland, California that
strongly favors nuclear energy, assessed that GFRs may face too many significant hurdles to
reach commercialization. They drew attention to the lack of existing materials that can
withstand high irradiation fields that would be present in GFRs’ cores; the fact that no gascooled fast reactor has even been built for testing purposes; and “the reliance on engineered
safety systems rather than inherent safety features undermines its potential as a meltdownproof design.”32
Lead-Cooled Fast Reactor (LFR)
The LFR uses lead (Pb) or lead-bismuth (Pb-Bi) alloy coolant at atmospheric pressure and
high temperature due to the very high boiling point of the coolant. Because of the neutron
scattering properties of lead, the chain reaction makes use of fast neutrons. The expected
efficiency of the LFR is above 42 percent and there are a number of attractive safety
properties, including:

The chemical inertness of the coolants; in particular, lead does not react
exothermically with water or air unlike liquid sodium (as discussed later);

The high boiling point of lead reduces the risk of voids being created in the core
(that is, the core will tend to be covered with coolant);

The high density of lead helps with fuel dispersion instead of compaction in the
event of core destruction, minimizing the risk of a criticality accident;

The thermal properties of lead provide thermal inertia;

Lead shields gamma rays and also retains some highly radioactive fission products in
the event of an accident;

Lead has very low neutron moderation that allows for increased spacing between
fuel pins and thus reducing the risk of coolant flow blockage; and

The simplified coolant flow path and low core pressure drop provide natural
convection cooling for shutdown heat removal.
However, LFRs still have challenges that need to be addressed. First, to prevent lead’s
erosive and corrosive effects on structural steel at high temperatures and flow rates, there is
32
Ted Nordhaus, Jessica Lovering, and Michael Shellenberger, “How to Make Nuclear
Cheap: Safety, Readiness, Modularity, and Efficiency,” The Breakthrough Institute, June
2014, p. 49.
Federation of American Scientists
|23
the need for chemical control by introducing oxygen into the coolant, creating an oxidizing
layer in the structural materials. In the event of an earthquake, the high structural stress from
heavy lead might damage the reactor. Due to lead’s opacity, monitoring and inspecting the
core’s components is difficult. Because of lead’s high melting point, the primary coolant has
to be maintained above 327oC to prevent solidification of the coolant. Moreover, due to the
heavy metal toxicity of lead, special procedures would have to be developed and
implemented to dispose of it safely.
The only significant operating experience of Pb-Bi reactors has been their use in about a half
dozen Russian submarines, two of which experienced major reactor problems. Also, it is not
easy to extrapolate the successful submarines’ reactors’ experience to the LFR notional
design because they were operated at significantly lower temperatures and used an
epithermal (not fast) neutron spectrum. A safety issue of these reactors was the accumulation
of polonium-210, a strong alpha-emitter; the Russian Federation developed techniques to
trap and remove the polonium.
Several contrasting designs and power rating sizes are being studied in a number of
countries, including China, Korea, Japan, Russia, the United States, and member countries of
Euratom. Interested readers wanting to know more about the various activities are invited to
consult the Gen IV’s 2014 Roadmap and website. The country furthest along to a prototype
demonstration after 2020 is most likely Russia with its BREST-OD-300 and SVBR-100
reactors based on the Russian navy’s previous experience.
Most likely, if LFRs were to reach commercialization, they would be smaller in size to keep
the total weight and volume of lead low. For instance, Gen4 Energy (formerly known as
Hyperion Power) is developing the Gen4Module, a small 25 MW modular LFR with a 10year lifetime.33 These so-called “nuclear batteries” appear to offer the most promising
pathway forward for LFRs (assuming that significant technical challenges, as mentioned
above, can be overcome).
Molten Salt Reactor (MSR)
The MSR is typically classified into two types of designs. In the first type, fissile material is
dissolved in a molten fluoride salt. The second type uses the molten salt as a coolant for a
core fueled with coated fuel particles. The coating provides protection by blocking
radioactive fission products from entering the coolant. In contrast, the first type would use a
method to capture the fission products that are circulating in the molten salt. But with either
method, ensuring an environment free of radioactive contamination is a primary objective.
A relatively old idea, the MSR has received substantial attention in recent years, from
staunch, long-standing proponents of proliferation-resistance to bright, younger engineers at
MIT and Silicon Valley venture capitalists. Those who do not know the history of the MSR
might be surprised to learn that it derived from the 1950s investigation of the Aircraft
Reactor Experiment, which attempted to design and build a nuclear reactor safe enough to
power airplanes. While this experiment did not result in nuclear-powered aircraft (probably
thankfully so), it did lead to the Molten Salt Reactor Experiment at Oak Ridge National
33
For details, see http://www.gen4energy.com, accessed on May 31, 2015.
Federation of American Scientists
|24
Laboratory. The legendary nuclear energy leader Dr. Alvin Weinberg worked on this
experiment and was a proponent of this technology. But by the early 1970s, the United
States government had pulled funding for the experiment or for further R&D to continue
investigating MSRs.
The revival of recent interest has much to do with the safety features of MSRs. For example,
they would have large negative temperature and void reactivity coefficients, meaning that fast
temperature increases or the creation of vacuums or less dense volumes, or “voids,” would
decrease reactivity and thus drive the reactor into a safer status. In the first design type,
where fissile material dissolved in the salt, if electrical power is lost, a frozen plug at the
bottom of the primary piping will melt and result in the molten material flowing and sinking
to a safe container. Moreover, since these reactors operate at or near atmospheric pressure,
there are not potential safety problems due to loss of pressurization as in PWRs or even
GFRs.
Another reason for excitement about MSRs is proliferation-resistance. In a mode under
which MSRs use the thorium-232/uranium-233 fuel cycle, the reactors are believed to offer
significant proliferation-resistance. Although U-233 is fissile and would be useful in firstgeneration gun-type nuclear explosives, the thorium-uranium fuel cycle would produce
uranium-232, which, in even relatively small proportional amounts, would create a radiation
hazard for any workers attempting to form the uranium mixture into nuclear bombs.34
Because uranium-232 and uranium-233 have nearly identical chemical properties, it would
not be possible to use chemical processing techniques to separate them. However, there is a
possibility that protactinium, the intermediate element in the chain of production from
thorium-232 to uranium-233, could be separated early enough in the production process to
reduce the creation of uranium-232. With a half-life of about 27 days, protactinium-233
decays to uranium-233. But to even make one kilogram of uranium-233, it would require
about 1.5 metric tons of thorium-232.35 To get enough uranium-233 for even one bomb
would require eight times this amount of thorium. Thus, although this fuel cycle is not
proliferation-proof, it appears to offer significant proliferation-resistance.
The stumbling block in adoption of the thorium fuel cycle appears to be that the oncethrough uranium fuel cycle is very entrenched, as mentioned earlier in this report. However,
countries with abundant supplies of thorium (such as India) have expressed interest in
developing prototypes. Thorium is estimated to be three to four times more abundant than
uranium. The liquid fluoride thorium reactor (LFTR) has received significant attention as a
promising technology.36
34
For an independent assessment of this fuel cycle, see Jungmin Kang and Frank N. von
Hippel, “U-232 and the Proliferation-Resistance of U-233 in Spent Fuel,” Science & Global
Security, Vol. 9, 2001, pp. 1-32.
35
Stephen F. Ashley, Geoffrey T. Parks, William J. Nuttall, Colin Boxall, and Robin W.
Grimes, “Nuclear Energy: Thorium has risks,” Nature, vol. 492, December 6, 2012, pp. 3133.
36
Robert Hargraves and Ralph Moir, “Liquid Fuel Nuclear Reactors,” Physics and Society,
January 2011, http://www.aps.org/units/fps/newsletters/201101/hargraves.cfm.
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Moreover, the second design type, often called fluoride salt-cooled high-temperature reactor
(FHR), has features that might allow large-scale power generation with full-scale passive
safety characteristics. In addition, FHRs offer high-efficiency electricity generation coupled
with process heat production for industrial purposes. A newer design from researchers at
MIT, the University of California, Berkeley, and the University of Wisconsin combines an
FHR with a natural gas power plant to give base load and peaking electrical power
distribution. The MIT-Berkeley-Wisconsin team has done an economic cost-benefit analysis
that indicates that this hybrid mode of electricity generation might make this type of FHR
cost competitive with fossil-fuel power plants.37
Another example of an FHR that has had some significant R&D is the pebble-bed advanced
high-temperature reactor (PB-AHTR), which uses TRISO ceramic fuel particles. Research
on TRISO fuel dates back to 1959 in the United Kingdom. This fuel type was later tested in
two German gas-cooled reactors. More recently, China and Japan have investigated TRISO
fuels. PB-AHTR designers are planning to apply modular construction principles used in
Korea and China.
Furthermore, MSRs could offer significant benefits in nuclear waste management. Because
of their fuel versatility, these reactors might be able to consume many fissionable materials,
such as those greater in mass than uranium. This could help alleviate the long term burden
on nuclear waste repositories, such that a batch of radioactive material would only have to be
stored for a few hundred years until it reaches low levels of radioactivity in contrast to tens
of thousands of years for the once-through uranium fuel cycle. For example, Transatomic
Power, a recent startup company founded by two younger MIT-educated nuclear engineers
is investigating this design under the title of Waste-Annihilating Molten Salt Reactor
(WAMSR).38 But much more research is needed to develop this transuranic consuming
reactor concept. There might need to be multiple recycles in order to have burn up that
results in very low levels of transuranic materials.
What are the additional challenges for MSRs? For FHRs, they will need further research on
fiber ceramic composites, fuel elements and assemblies, tritium release prevention
technologies, and corrosion protection technologies.39 For the other major design concept,
several R&D issues need to be addressed, including the physical-chemical behavior of fuel
salts and the behavior of radioactive fission products in the salts, the compatibility of salts
with structural materials for fuel and coolant circuits, on-site fuel processing methods, as
well as instrumentation and control of liquid salt.40
37
Charles Forsberg, Per F. Peterson, Lin-Wen Hu, and Kumar Sridharan, “Baseload nuclear
with variable electricity to the grid,” Nuclear News, March 2015, pp. 77-81.
38
Bryan Walsh, “Amid Economic and Safety Concerns, Nuclear Advocates Pin Their Hopes
on New Designs,” Time.com, August 5, 2013; Josh Freed, “Back to the Future: Advanced
Nuclear Energy and the Battle Against Climate Change,” Brookings Magazine, December
2014.
39
See: David E. Holcomb et al., “Fluoride Salt-Cooled High-Temperature Reactor
Technology Development and Demonstration Roadmap,” Oak Ridge National Laboratory
technical report, September 2013.
40
GIF Roadmap, 2014, pp. 31-32.
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While significant research challenges remain, the safety features and other potential benefits
make MSRs attractive. Also, considering the R&D that has been done particularly on the
PB-AHTR concept, some analysts predict a move toward commercialization by the mid2020s.41
Sodium-Cooled Fast Reactor (SFR)
Similar to some other Generation IV design concepts, the SFR is not a “new” technology as
several nations have had R&D and prototype commercial-scale SFRs for decades. As
mentioned in the beginning of this report, nuclear engineering pioneers in the 1940s were
exploring this concept because of the perceived need for breeder reactors. The SFR uses
liquid sodium as coolant in a fast-neutron reaction. Liquid sodium allows for a low-pressure
coolant system with a high-power density core. Due to its physical and chemical properties,
liquid sodium also has high thermal inertia and a large margin to coolant boiling, both of
which are important safety features. But the biggest safety concern remains that sodium
reacts chemically with air and water and thus needs a sealed coolant system.
The GIF 2014 Roadmap highlights three options for SFRs: pool, loop, and modular. Thus,
the GIF research plan has three sizes of SFR that are being studied:
I.
II.
III.
“A large size (600 to 1500 MWe) loop-type reactor with mixed uranium-plutonium
oxide fuel and potentially MA [minor actinide]-bearing fuels, supported by a fuel
cycle with advanced aqueous processing at a central location serving a number of
reactors;
An intermediate-to-large size (300 to 1500 MWe) pool-type reactor with oxide or
metal fuel; and
A small size (50 to 150 MWe) modular type reactor with metal-alloy fuel (uraniumplutonium-MA-zirconium), supported by a fuel cycle based on pyrometallurgical
processing in facilities integrated with the reactor.”42
According to the GIF Roadmap, the SFR “is an attractive energy source for nations that
desire to make the best use of limited fuel resources and manage nuclear waste by closing the
fuel cycle. Its fast neutron spectrum enables full actinide recycling and greatly extends
uranium resources compared to thermal reactors. The SFR technology is more mature than
other fast reactor technologies and thus is deployable in the very near-term for actinide
management. With innovations to reduce capital cost, the SFR also aims to be economically
competitive in future electricity markets.”43
Researchers outside of GIF who are concerned about proliferation have produced a lengthy
report that critiques SFRs. That group points to a long history of sodium leaks and some
sodium fires at experimental reactors in a number of countries. They also view SFRs as too
expensive as compared to LWRs given the added features that would have to be put in place
41
See, for example, the Breakthrough Institute 2014 report, p. 37.
GIF Roadmap 2014, p. 34.
43
Ibid, p. 35.
42
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to minimize the likelihood of sodium leaks. Moreover, they express skepticism that uranium
shortages will increase uranium prices such that SFRs appear attractive from a breeding and
plutonium recycling perspective.44 Nonetheless, countries with concerns about energy
security such as Korea, Japan, and France still have interest in SFRs, but of these countries,
Korea is most likely to move forward due to its needs for reducing the volume of high level
waste and for removing transuranics from this waste that would require tens of thousands of
years of storage. Japan is struggling with the future of its LWRs, and (even though Monju’s
SFR is an older design from before 1985) the 1995 sodium fire at Monju has stalled further
development of this technology in that country. About five years ago, France shut down its
only operating SFR. However, China, India, and Russia are notably pursuing SFR-type
technologies with Russia having the most operating experience of those countries.
Further research is needed to ensure that the sodium remains well sealed while not having
the additional sealant equipment increase the cost; this would allow the plant to become
economically competitive. Also, “void swelling,” or the tendency of metallic fuel elements to
swell under irradiation, and build-up of fission product gases has been a problem with past
SFRs. Methods to vent these gases can mitigate void swelling. In addition, R&D is required
to ensure that materials can withstand neutron embrittlement and metallic creep under
prolonged radiation exposure, key for reactors designed to last up to 60 years. Further work
is also needed in developing on-site reprocessing systems. While Argonne National
Laboratory did investigate this method with the integral fast reactor (IFR) system under
development in the 1980s and into the 1990s, the program’s funding was cut in the mid1990s. Joint research between Korea and the United States in pyroprocessing might result in
demonstrating the viability of this type of method. The full system, however, would have to
be demonstrated in a prototype. Korea is aiming to build a prototype by 2028 and then
move toward deployment of a full-scale commercial system in the decade after that year.45
Japan continues to express interest in SFRs, but as mentioned, the long shutdown of the
Monju reactor and the continued shutdown of Japan’s thermal reactors raise doubts about
Japan’s capacity to renew its SFR program in the coming years.
Supercritical-Water-Cooled Reactor (SCWR)
By increasing temperatures and pressures to the part of the water phase diagram in which
water becomes supercritical, the designers of the SCWR aim to create a highly efficient
power plant. When water is supercritical, steam and liquid have the same density, so the
SCWR does not require extensive equipment to separate and dry steam, and the supercritical
water goes directly from the reactor to the turbine. This design simplicity saves on expensive
steam generators, steam dryers, recirculation pumps, and secondary cooling system. By not
requiring all of these pieces of equipment, the plant can be made significantly smaller than a
typical PWR (but with an equal power rating). The efficiency is estimated to be 45 percent.
44
Thomas B. Cochran et el., “Fast Breeder Reactor Programs: History and Status,” A
Research Report of the International Panel on Fissile Materials, February 2010.
45
Yeong-il Kim, “Status of SFR Development in Korea,” KAERI representative’s
presentation to FR13, Paris, France, March 5, 2013,
https://www.iaea.org/NuclearPower/Downloadable/Meetings/2013/2013-03-04-03-07CF-NPTD/T1.1/T1.1.kim.pdf, accessed on June 11, 2015.
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However, like the PWR, the SCWR has features that have raised safety concerns. The water
coolant can be corrosive; the pressurized system requires engineered safety systems; and
backup power is needed to keep the water in a supercritical state. In particular, the pressure
vessel would have about 1.5 times the pressure of a typical PWR’s pressure vessel. This fact
makes implementation of passive safety systems increasingly challenging. Also, the fast
neutron model of an SCWR has a positive void coefficient that may result, if steam bubbles
or a vacuum forms, in uncontrolled heating from reactivity surges. Advanced, very rigorous
and corrosion-resistant materials will have to be developed for the SCWR to be viable.
As to the commercial pathway, one advantage is that the U.S. Nuclear Regulatory
Commission (NRC) is very familiar with pressurized water reactor systems, and this could
fare well for the SCWR. But the NRC would need to know whether the issues regarding
materials have been resolved. The Breakthrough Institute assessed that this is “one of the
least promising Gen IV designs due to its higher core temperatures, its greater neutron flux,
and its use of novel materials.”46 Moreover, the R&D challenges are estimated to take many
years for testing and optimization to qualify for meeting engineering standards such as
American Society of Mechanical Engineers (ASME) codes. The GIF Roadmap mentions few
countries that are actively pursuing research on SCWRs and that such work mostly consists
of conceptual modeling of designs. That Roadmap emphasizes the need for extensive testing
of materials within the next five years and then proceeding to tests of a small-scale fuel
assembly and potentially a SCWR prototype in the ten-year time horizon.47
Very-High-Temperature Reactor (VHTR)
The VHTR can be considered more of an “evolutionary” rather than a “revolutionary”
design, given the previous experience with earlier generation, high-temperature, gas-cooled
reactors. The exciting potential of the VHTR is its operating temperatures between 750oC
and 950oC and the possibility of even more than 1000oC in the future. These very high
temperatures can permit highly efficient generation of electricity (47 percent for 850oC and
50 percent for 950oC operations) and production of hydrogen through thermochemical
processes, which are efficient means to generate hydrogen. The hydrogen can then be used
in a variety of applications such as fuel cells for powering vehicles and buildings without
harmful emissions. Also, a VHTR can supply heat for industrial processes in refineries and
petrochemical applications. The reactor core of a VHTR can use a prismatic-block-type fuel
such as the Japanese HTTR or a pebble-bed type fuel such as the Chinese HTR-10.
These reactors have safety features that are believed to reduce significantly the likelihood of
major accidents. Moreover, the strong negative temperature coefficient of reactivity and the
high heat capacity of the graphite core are specific reasons for this safety assessment. In
addition, tests of the TRISO fuel have indicated that this reactor concept “does not need
off-site power to survive multiple failures or severe natural events such as occurred at the
Fukushima Daiichi nuclear station.”48 In particular, in 2004, China performed a loss of
coolant test of an HTGR in front of a panel from the International Atomic Energy Agency,
and the reactor demonstrated that it dissipated heat without any human or mechanical
46
The Breakthrough Institute, 2014, p. 39.
GIF Roadmap, 2014, pp. 42-45.
48
Ibid, p. 46.
47
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intervention.49 These reactors’ low power densities make it difficult for them to overheat.
The helium coolant is also non-corrosive.
This reactor type is likely to be the closest to commercialization of the advanced thermal
type reactors considering the operating experience of the previous generation and the
assessment that construction materials are already certified. Similarities with LWRs could
pave the way for NRC certification and eventual licensing. However, the unique heat
dissipation feature of a VHTR could hold up NRC’s certification because the NRC’s rules
have focused on assessing means for preventing loss of coolant rather than heat dissipation
through natural means after coolant has been lost. China has experience with prototype
pebble-bed reactors and is moving toward potential construction of a commercial-scale
HTGR by 2020. This might then lead to eventual construction of a VHTR after 2020. In the
United States and other countries, public-private partnerships between government and
chemical companies needing process heat could help jump start demonstration of a
commercial-scale VHTR. Such a partnership could leverage a cost-sharing grant.50
GIF’s Working Groups
From its start, GIF recognized that progress on these systems depended on a thorough
understanding of the economics, safety, and proliferation resistance and physical protection
requirements. Three working groups were formed to investigate these important issue areas.
Presented below are the main points that need to be addressed by each working group.
Economic Modeling Working Group
If the advanced nuclear energy systems are not cost-competitive over other energy sources,
they will not be adopted by utilities. While a carbon tax or cap-and-trade scheme would help
nuclear power, this cannot be counted on to take place, especially in the United States given
the highly partisan split over taxation and the size and role of the federal government. GIF
has not relied on factoring in carbon fees in its economic assessments. GIF’s Economic
Modeling Working Group has worked to develop methodology and tools that would assess
these systems on the bases that there would be:
I.
A life cycle cost advantage over other energy sources (i.e. to have a lower levelized
unit cost of energy over their lifetime)51; and
II.
A level of financial risk comparable to other energy projects (i.e. to involve similar
total capital investment and capital at risk).
49
The Breakthrough Institute, 2014, p. 29.
Ibid, p. 33.
51
Levelized cost of electricity “represents the per-kilowatt hour cost (in real dollars) of
building and operating a power plant over an assumed financial life and duty cycle,”
according to William Pentland, writing in Forbes.com, November 29, 2014,
http://www.forbes.com/sites/williampentland/2014/11/29/levelized-cost-of-electricityrenewable-energys-ticking-time-bomb/
50
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This working group also recognized that each country has specific economic and energy
security assessments that could result in differing decisions about GIF energy systems. To
assist in decision-making, the working group is iterating, as work progresses on each system,
an integrated economic model to compare the various GIF technologies, “as well as to
answer optimal configuration questions, such as which fuel cycle is most suitable in different
parts of the world and what are the optimal deployment ratios.”52 In future years, the
working group will continue to refine its G4ECONS cost estimating code with substantial
input from the R&D being done on the various systems.
Risk and Safety Working Group
In the past few years, this group has focused on creating an integrated framework for
assessing risk and safety issues. Specifically, it is building on its 2011 report titled “An
Integrated Safety Assessment Methodology (ISAM) for Generation IV Nuclear Systems.”53
This framework would be used in three main ways:
I.
II.
III.
“Throughout the concept development and design phases with insights derived from
ISAM serving to actively drive the course of the design evolution. In this application,
ISAM is used to develop a more detailed understanding of design vulnerabilities and
resulting contributions to risk. Based on this detailed understanding of
vulnerabilities, new safety provisions or design improvements can be identified,
developed and implemented relatively early;
Selected elements of the methodology will be applied at various points throughout
the design evolution to yield an objective understanding of risk contributors, safety
margins, effectiveness of safety-related design provisions, sources and impacts of
uncertainties, and other safety-related issues that are important to decision makers;
and
ISAM can be applied in the late stages of design maturity to measure the level of
safety and risk associated with a given design relative to safety objectives or licensing
criteria. In this way, ISAM will allow evaluation of a particular Generation IV
concept or design relative to various potentially applicable safety metrics or ‘figures
of merit.’ This post facto application of ISAM will be useful especially for decision
makers and regulators who require objective measures of safety for licensing
purposes or to support certain late-stage design selection decisions.”
Proliferation Resistance and Physical Protection Working Group
This working group has worked closely with the Risk and Safety Working group due to
overlapping issues. The Proliferation Resistance and Physical Protection Working Group has
especially coordinated its efforts with the International Atomic Energy Agency’s Innovative
Nuclear Reactors and Fuel Cycles (INPRO) and safeguards division. An IAEA
52
GIF Roadmap 2014, p. 53.
https://www.gen-4.org/gif/upload/docs/application/pdf/201309/gif_rsgw_2010_2_isamrev1_finalforeg17june2011.pdf, accessed on May 31, 2015.
53
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representative sits on the GIF working group. Specific countries have applied this working
group’s framework to evaluation of alternative spent fuel separation technologies.
This group is emphasizing to GIF and member nations that new and innovative designs
need to incorporate proliferation resistance and physical protection principles into the
designs. Safeguards are expected to be more effective if they are enabled by design. Thus, a
close working relationship is needed between safeguards specialists at the IAEA and member
nations and the designers of Gen IV systems.
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Small is Attractive: Why there is Renewed Interest in Small, Modular
Reactors
In a sense, submarines’ reactors are small reactors and have been in use for 60 years. But
these reactors were not initially designed with economic competitiveness in mind. They were
(and are) intended to meet rigorous military missions. Nonetheless, companies such as
Babcock & Wilcox, which are involved with naval reactors, have ventured into the
commercial sector to develop LWR-versions that can start at small power levels of 50 to 300
MWe and then be scaled up by combining multiple modular reactors to essentially form
larger power blocks on the order of 600 to 1200 MWe. SMRs have generated excitement in
the Department of Energy and in other countries nuclear research agencies because they
appear to offer a means to scale up by starting at an apparently manageable $1 billion or so
cost. Then, as a utility can afford to add on other modules over time, the power generated
can go up. Still, utilities, certainly those in the United States, are risk-averse, and they would
be reluctant to spend $1 billion on a new technology. Consequently, despite U.S.
government support for some tens of millions of dollars for SMRs, the scale of the financial
commitment will most likely need to be an order of magnitude higher, and the government
could stimulate deployment by demonstrating one or more SMRs to power military bases or
national laboratories.
Another reason for rising excitement in SMRs is that they appear well-suited for many
countries in the developing world that have smaller electrical grids. A general rule is that an
electrical grid should not have more than 10 percent of its power coming from one power
plant. For example, a 1,000 MWe typical LWR would not be suitable for a grid that could
only manage 8,000 MWe. This size LWR might “trip the grid” when it is brought on- or offline. While SMRs have sometimes been described as “plug-and-play,” they will still require
extensive training of personnel in the developing countries that order them. Even SMRs that
have lifetime reactor cores or SMRs that are buried underground will need well-trained
security forces to protect them. Thus, SMRs have generated significant excitement for good
reason, but their management will still need adequate attention to ensure safety and security.
While detailed explanations of the designs of SMRs are beyond the scope of this report, the
following are presented as salient features of some companies’ and research institutes’
designs that are of recent or renewed interest. A number of the GIF designs are envisioned
in smaller and modular sizes, such as the LFR, MSR, and SFR, for reasons described in
previous sections.

54
Babcock & Wilcox Nuclear Energy, Inc. has designed the mPower advanced light
warer reactor. This design is an integral PWR or iPWR that has passive and other
innovative safety features incorporated in a self-contained module with the reactor
core and steam generator located in a common reactor vessel; that is the “integral”
aspect of the design. The mPower design is rated at 180 MWe. B&W has been
actively engaged with the NRC in working to move toward design certification and
eventual commercial licensing.54
See http://www.nrc.gov/reactors/advanced/mpower.html, accessed on May 31, 2015.
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
The NRC has also been in discussions with NuScale Power (NuScale) about preapplication activities since 2008. NuScale is seeking to commercialize a modular,
scalable 50 MWe iPWR design. It would have a 24-month refueling cycle and be
fueled with 4.95 percent low enriched uranium.55 This design and the mPower design
would likely be commercially attractive primarily due to their basis in well-known
LWR technology.

As to non-LWR SMRs, GE Hitachi Nuclear Energy (GEH), for example, has been
developing the PRISM design, which is a small, modular, pool-type, and sodiumcooled fast reactor with metallic fuel. The thermal power rating is 840 MWth. The
NRC had actually done some related pre-application work on a similar design in the
early 1990s. GEH has interacted with the NRC since 2010 with a draft licensing
strategy. GEH touts the benefits of the capability to reduce the nuclear waste burden
by consuming transuranic materials.56

Toshiba Corporation is working on developing the Super-Safe, Small and Simple (4S)
design, which is a small, pool-type, sodium-cooled fast reactor with metallic fuel.
According to its designers, its comparative advantage is its suitability for remote
locations to operate for 30 years without refueling. The 4S has two power rating
modules: 10 MWe or 50MWe.57 The NRC and Toshiba began discussions in 2007
about pre-application activities.

KAERI has been moving forward with its SMART (system-integrated modular
advanced reactor) technology, marketing it to clients in the Middle East in particular
because the SMART reactor offers desalination as a comparative advantage.58
SMART can deliver either 100 MWe electric power or 90 MWe with concurrent
40,000 tons of desalinated water for up to 100,000 residents. The designers have
blended a mixture of new innovative design features for passive safety with wellproven PWR technologies. They believe that this hybrid approach will make SMART
economically competitive because it has the best of new and old design principles.
Also, they underscore the system simplification, modular construction, and reduced
construction time as other comparative advantages.59 On July 4, 2012, after a
thorough review, the Korean Nuclear Safety and Security Commission granted
design approval to SMART.
55
See http://www.nuscalepower.com/our-technology/technology-overview, accessed on
May 31, 2015.
56
See http://gehitachiprism.com/what-is-prism/, accessed on May 31, 2015.
57
See http://www.toshiba.com/tane/products_4s.jsp, accessed on May 31, 2015.
58
Chen Kane and Miles A. Pomper, “Reactor Race: South Korea’s Nuclear Export Successes
and Challenges,” Korea Economic Institute of America, Report, May 2013.
59
Keung Koo Kim et al., “SMART: The First Licensed Advanced Integral Reactor,” Journal
of Energy and Power Engineering, 8 (2014) 94-102.
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Regulatory Requirements for Licensing and Constructing Advanced
Nuclear Energy Systems
In response to an order from the U.S. Congress, the U.S. Nuclear Regulatory Commission in
August 2012 published a detailed report that discusses the status of the agency in preparing
for potential licensing of advanced nuclear energy systems and the additional needs of the
agency to meet the foreseeable future licensing applications. Significant issues that will affect
certification and licensing of advanced nuclear energy systems are highlighted below.
The NRC report lays out four timeframes:
I.
“Within the near term, in addition to current and planned Generation III+ licensing
activities, the NRC anticipates licensing activities focused on integral pressurizedwater reactor designs;
II.
Within the longer term, the NRC anticipates continuation of the near-term activities
and expanded activities pertaining to liquid-metal cooled reactor designs;
III.
Within the horizon timeframe, licensing activities to continuation of those from the
prior timeframes, may include one or more advanced reactor concepts currently
identified for research by the Generation IV International Forum and supported by
DOE; and
IV.
For the beyond-the-horizon timeframe, NRC licensing activities would correlate
with (1) the DOE’s Nuclear Energy Research and Development Roadmap—Report
to Congress, issued April 2010, (2) recommendations of the Blue Ribbon
Commission on America’s Nuclear Future—Report to the Secretary of Energy,
issued January 2012, and (3) U.S. national policy regarding the nuclear fuel cycle.”60
The NRC is geared primarily toward evaluating and licensing LWR-type reactors. The more
that a reactor’s design deviates from an LWR-design, the more time and resources
(personnel, simulations, and testing facilities) the NRC will need to make a proper
evaluation. It is important to recognize that the NRC’s role is safety and not promotion of
nuclear technologies. The NRC favors a “go-slow-and-steady” approach that proponents of
new nuclear technologies could consider too cautious. But the NRC has to make sure that a
thorough review is done in order to fulfill its charter of protecting the public. Thus, the
NRC’s report to Congress highlights the important requirement for vendors to submit as
complete technical documents as possible and to answer all questions from the NRC in a
thorough manner. Vendors, however, are concerned that the application costs are very
high—and could end up being several hundred million dollars. The DOE has set aside some
funds for regulatory financial support to help mitigate the high costs. But many vendors still
have concerns about the prohibitive costs.
60
U.S. Nuclear Regulatory Commission, “Report to Congress: Advanced Reactor Licensing,”
August 2012, p. v.
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In addition to having to allocate more resources to understand designs that are significantly
different from LWR designs, the NRC flags the following as a crucial issue: “The
consideration of review and oversight of new nuclear fuel designs and their production. Any
advanced reactor design that uses fuel that differs significantly from the current type
(zirconium-clad, low-enriched uranium dioxide) will require the evaluation of technical and
regulatory approaches to the licensing of fuel fabrication, transportation, storage, and waste
disposal operations.”61 Thus, the NRC will have more scrutiny for different fuel types and
processes other than typical LWR fuels.
The NRC also raises concerns about its international reputation. The NRC report explicitly
mentions that its standards are often viewed as “the gold standard.” Therefore, the NRC
wants to maintain its credibility and the subtext is that if it is not careful in evaluating and
licensing advanced nuclear energy systems, it could jeopardize this stellar reputation.
The NRC has specified three major components in order to be ready for high quality
evaluation of advanced nuclear designs: (1) regulatory structure; (2) research efforts; and (3)
human resource development. The first component will require significant reliance on the
MDEP approach. The MDEP is the Multinational Design Evaluation Program of the
Nuclear Energy Agency, a body of 14 countries’ regulatory agencies that work to harmonize
their efforts in considering the regulatory issues involved with advanced nuclear energy
systems (as well as Generation III and III+).62 In pursuing international engagements, the NRC
would maintain interaction with DOE and the domestic industry to ensure broad
stakeholder input regarding the technologies, licensing and operating experience, and overall
safety philosophy.
“To address research efforts, NRC envisions working closely with DOE, the Electric Power
Research Institute, the Nuclear Energy Agency, IAEA, and the nuclear industry to motivate,
manage, and co-fund the research efforts, including unique facility development needed to
support development and licensing of advanced reactor technologies. … The NRC will
remain mindful of the need for clear independence in the regulatory aspects of these
research endeavors by ensuring development of a clear and defensible set of research results
to support regulatory decisions.
“Regarding human resource requirements, NRC envisions coordinating its efforts with
DOE, the domestic nuclear industry, and academia, to support national programs of
classroom, laboratory, and field experience, funded in part by the NRC Educational Grants
Program, which would support development, licensing, construction, and operation of
nuclear power plants and the associated fuel fabrication facilities. To the extent that
interaction with international programs would facilitate the NRC’s mission to protect public
health and safety and the common defense and security in the licensing and oversight of new
reactor technologies and fuel facilities, our plans would include those interactions. For
advanced technologies, the NRC expects that coordinated programs led by DOE and the
industry would support the NRC’s skill needs for advanced reactor technologies.”63
61
Ibid, p. v.
See https://www.oecd-nea.org/mdep/, accessed on May 31, 2015.
63
NRC Report to Congress, August 2012, pp. vi-vii.
62
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Knowledge Management, Knowledge Creation, and Training of the
Workforce
The NRC and other regulatory agencies recognize the critically important issue of knowledge
management (KM) “as a means of building and maintaining needed critical skills.” The
NRC, in particular, has “implemented three enterprise-wide KM initiatives in this regard: (1)
identifying high-value/high-risk (of loss) knowledge and skills the staff currently possesses;
(2) capturing and sharing that high-value/high-risk knowledge with other agency staff before
it is lost; and (3) identifying high-value opportunities for creation of Communities of Practice
that enable the sharing of knowledge and skills among those employees who perform the
same job function… Other ways the agency is ensuring that critical skills are available in the
future include the Grants Program and the Graduate Fellowship Program.”64
The advanced nuclear energy systems of the future will require highly qualified and skilled
people to operate and manage them. Unfortunately, the aging nuclear workforce presents a
major challenge to bridging the gap between the generations. New nuclear construction in
certain countries such as China and Korea has helped address this problem that is growing in
the United States and much of Europe. In the United States, DOE in recent years has
invested tens of millions of dollars into programs to motivate the next generation to become
involved in cutting edge R&D in advanced nuclear energy systems. Notably, in the past year,
the DOE through the Nuclear Energy University Program (NEUP) has awarded more than
$30 million “to support 44 university-led projects aimed at developing innovative
technologies in the areas of fuel cycle R&D, reactor concepts research, development, and
demonstration, and advanced modeling and simulation. These NEUP projects will be
headed by 30 universities in more than 20 states.”65 There are about 30 university nuclear
engineering programs throughout the United States. In addition, another $20 million is set
aside for five integrated research projects that focus on high priority research challenges with
the lead teams at the Georgia Institute of Technology, MIT, Pennsylvania State University,
the University of South Carolina, and the University of Wisconsin. Moreover, DOE has
awarded more than $11 million to 12 research and development projects led by U.S.
universities, DOE national laboratories, and industry in support of the Nuclear Energy
Enabling Technologies Crosscutting Technology Development Program.
The United States is not the only country that recognizes the importance of knowledge
management, the creation of new knowledge, and the preparation of the nuclear industry’s
workforce. The Republic of Korea has leveraged its top priority attention to this set of
educational issues in its capability to offer a comparative advantage in training the workforce
for the four power reactors under construction in the United Arab Emirates. The KAERI
Nuclear Training and Education Center (KNTC) has been a leading center for four decades
in elevating the Korean nuclear workforce to meet Korean national goals of achieving
“national self-reliance” as well as cooperating with international partners in helping train
other countries’ nuclear workers.66 Regarding knowledge management in the area of fast
64
Ibid, p. 34.
“DOE invests $67 million to advance nuclear technology,” Nuclear News, October 2014, p.
88.
66
See http://www.kntc.re.kr/english/about/introduction.jsp, accessed on May 31, 2015.
65
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neutron reactors, India has an extensive program based at the Indira Gandhi Centre for
Atomic Research. In addition to its domestic training and knowledge acquisition and
preservation, this center is coordinating with the Fast Reactor Knowledge Organization
System (FRKOS) being established with the IAEA. “FRKOS consists of an electronic
repository of FR knowledge and experience from various countries with facilities for
effective search and knowledge mining.”67
Through these cooperative educational activities and knowledge sharing, advanced nuclear
energy systems could make improvements much faster than if each country acted
independently.
67
K. K. Kuriakose et al., “Knowledge Management in Fast Reactors,” Energy Procedia, 7
(2011) 672-677.
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Conclusions: What Needs to be Done for Making Further Progress?
While there is excitement about the potential for commercialization of advanced nuclear
energy systems, much more remains to be done for these technologies to be adopted by the
market and then rise to widespread deployment. The review nature of this report has
identified major themes and lessons learned from development of LWR technology and
previous efforts on non-LWR technologies. Instead of repeating findings from the executive
summary, the following are important issues to bear in mind during the next ten to twenty
years:

Government support is essential for new nuclear energy technologies. The level of
support offered to date in the United States is likely not adequate to help these
technologies cross from R&D to demonstration and deployment. Potentially several
billion dollars will be needed. Utilities tend to be risk-averse especially on projects
that can cost well over $1 billion.

International cooperation is vitally important in R&D and demonstration. While GIF
has provided a useful platform, it is likely that even more cooperation is needed
bilaterally and multi-laterally due to the complex challenges of many of these
technologies. In particular, although there has been bilateral cooperation between the
United States and other countries that use nuclear energy, such as Korea and Japan,
on R&D for advanced nuclear systems, these partnerships need to be strengthened
and deepened beyond the current scopes of work. For example, within the next five
years, the study examining pyroprocessing and fast reactors between KAERI and
Argonne National Laboratory and Idaho National Laboratory will be concluding;
assuming that this feasibility study shows promise for this technology, follow-on
work would need to progress to the next stage of building prototypes and then move
toward demonstration of a commercial-scale system. Governments in partnership
will have to commit to funding at the several billion dollar level to advance a
promising technology toward commercial demonstration. Cost-sharing between
governments can help reduce the overall financial load for each government.

Continued and expanded effort on multinational regulatory work is needed to
harmonize regulatory standards and to meet high standards across all nuclear power
countries that would help with widespread deployment of new nuclear technologies.
International cooperation is also essential in safeguards by design to move toward
more proliferation-resistant systems.

Small, modular reactors look promising, especially those technologies that offer longlived reactor cores, multiple modes of power generation, water desalination,
industrial heat, and hydrogen production. These multi-operational modes can help
even larger-sized power reactors make the economic case for their deployment.

Energy efficiency will be a major determining factor for these new technologies. The
more that they can provide energy conversion efficiencies greater than 40 percent the
more likely they could compete with natural gas-power plants. In addition, nuclear
plants that can offer base load electricity coupled with the capability to switch to load
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following or peaking power modes can further differentiate themselves in the
marketplace.

Governments and industry need to make adequate investments in knowledge
management, knowledge creation, and training for the next generations of nuclear
designers, builders, and plant operators.
Federation of American Scientists
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