Progress in Nuclear Energy, Vol. 31, No. 1/2, pp. 3-1 l, 1997
Copyright ~/1996 Published by Elsevier So ence Ltd
Printed in Great Britain
0149-1970N7 $32,0~
Pergamon
PII: S0149-1970(96)00001-7
THE INTEGRAL FAST REACTOR-AN OVERVIEW*
C. E. TILL, Y I. CHANG, and W. H. HANNUM
Argonne National Laboratory
Argonne, IL 60439
ABSTRACT
The Integral Fast Reactor (IFR) is a system that consists of a fast-spectrum nuclear reactor that uses metallic
fuel and liquid-metal (sodium) cooling, coupled with technology for high-temperature electrochemical
recycling, and with processes for preparing wastes for disposition. The concept is based on decades of
experience with fast reactors, adapted to priorities that have evolved markedly from those of the early days
of nuclear power. It has four essential, distinguishing features: efficient use of natural resources, inherent
safety characteristics, reduced burdens of nuclear waste, and unique proliferation resistance. These
fundamental characteristics offer benefits in economics and environmental protection. The fuel cycle never
involves separated plutonium, immediately simplifying the safeguarding task. Initiated in 1984 in response
to proliferation concerns identified in the International Nuclear Fuel Cycle Evaluation (INFCE, 1980), the
project has made substantial technical progress, with new potential applications coming to light as nuclear
weapons stockpiles are reduced and concerns about waste disposal increase. A breakthrough technology, the
IFR has the characteristics necessary for the next nuclear age.
Copyright ~c~1996 Published by Elsevier Science Lid
KEYWORDS
Actinide consumption; electrorefining; fast reactor; IFR; LMR; metallic fuel; nuclear fuel cycle; passive
safety; plutonium; proliferation resistance; pyroprocessing; reactor safety; recycling; waste management.
BACKGROUND
Today nuclear energy supplies approximately 20% of the world's electricity. A number of factors point to
a strong nuclear future (IAEA, 1993): a growing demand for electricity to meet the rising expectations of
an expanding world population, recognition that it is important to conserve all energy resources, a perceived
* Work supported by the U.S. Departmentof Energy, ReactorSystems, Development,and Technology,under Contract No.
W-31-109-ENG-38.
3
4
C.E. Till et al.
need to limit the production of greenhouse gases, a large existing investment in an international nuclear
infrastrneture, and a commitment to increased nuclear capacity in expanding economies (particularly in Asia).
During the last three decades, electricity consumption has marched in loekstep with economic growth in each
and every industrial country, even as total energy production has remained relatively flat in the U.S. and in
several other highly industrialized countries. The year 1993 was hailed for economic revival in the U.S.;
electricity sales jumped by 5%.
Nevertheless, several forces have aligned both to curb the pace of nuclear expansion and to shape its
development. These include economic forces arising from, among other things, a prolonged period of high
interest rates spanning the construction of most U.S. nuclear plants, pressure from certain groups worried
about nuclear waste disposal, safety concerns in the wake of the TMI-2 and Chernobyl accidents, and a shift
in U.S. energy policy to emphasize conservation instead of supply. For the past 20 years the reality of total
energy growth has consistently lagged far behind the projections of just a few years earlier. The installed
nuclear capacity at the beginning of the next millennium will be only half that predicted in the 1970s.
The maturing nuclear industry has been subjected to powerful changes that have made projections difficult
at best. Uranium reserves were significantly boosted in the 1980s by the discovery of rich deposits in
Australia. Uranium production has exceeded requirements as demand has failed to meet the expectations of
previous decades. Simultaneously, uranium prices have fallen with efficiency improvements, oversupply, and
competition. For the closed fuel cycle, initial recycling costs have proven to be high, although secondgeneration processing contracts in Europe are at significantly lower rates; the French have recently made a
40% reduction in the costs of their German contracts (deGalassus, 1994).
The International Atomic Energy Agency (IAEA) published its view of the future of nuclear energy in a
timely bulletin particularly germane to the debate going on in the U.S. (Semenov and Oi, 1993). Briefly,
the points made by the IAEA are:
Nuclear energy is already a large, important component of the world energy supply. A world population
expected to climb to over seven billion by 2010, coupled with rising expectations in rapidly developing
nations, leads some experts to predict a four-fold increase in electricity demand. Whatever the actual
demand turns out to be in the coming years, it cannot be met without a signifieant commitment to
nuclear energy.
2.
With experience and competition, recycling costs will continue to decline, uranium prices will inevitably
climb, and the economic pressure to recycle nuclear fuel will increase.
.
Closing the nuclear fuel cycle ultimately means developing fast reactors, for only in fast reactors can
plutonium be recycled again and again until it is gone. Recycling in LWRs is limited to just a few
cycles.
.
Geologic repositories, if they contain spent fuel or vitrified plutonium, will become potential plutonium
mines after the protective radiation from fission products decays sufficiently to justify the risk of
recovery.
5. Nuclear power development will likely proceed along at least two separate, independent paths: the oncethrough fuel cycle and the closed fuel cycle, depending on the political, economic, and environmental
considerations of individual nations.
The bottom line seems irrefutable: nuclear power is going to play an important role in future energy supply,
and some nations will reproeess their nuclear fuel.
The integralfast reactor
5
The concept of the Integral Fast Reactor (IFR) (Till and Chang, 1986, 1988) has been under development
at Argonne National Laboratory since 1984. From the outset, the effort has been focused specifically on
addressing the proliferation-related concerns regarding the thermal-reactor fuel cycle; i.e., on rectifying the
perceived shortcomings identified during the International Nuclear Fuel Cycle Evaluation (INFCE) (INFCE,
1980) and to the U.S. policy of discouraging the use of the PUREX reprocessing technology.
One key feature of the IFR is that the fuel is metallic, which brings pronounced benefits over oxide in
improved inherent safety and lower processing costs. MetaUie fuel was, in fact, the original choice in the
early development of liquid-metal reactors, and was successfully developed and used as the driver fuel in
EBR-II. During 1964-1969, about 35,000 metallic fuel pins were processed and refabricated in the EBR-II
Fuel Cycle Facility, using an early pyrometaUurgical process. The basis for the reactor design is described
in Chapter 2, a specific design realization in Chapter 3, and the fundamental safety basis in Chapter 4.
Except for the continuing development of metallic fuel for the driver in EBR-II, the national fuel
development program shifted in the late 1960s to emphasize oxide fuels, since the metallic fuels available
at that time could achieve neither the high bumup nor the high-temperature performance needed for
economical operation. That picture has now changed, thanks to discoveries at EBR-II in the late 1960s and
to design developments and irradiation experience in the 1970s. Metallic fuel can now be designed for high
burnup and superior tolerance to heavy irradiation. The IFR fuels development program is discussed in
Chapter 5.
The extensive EBR-II driver-fuel experience during the 1960s was with an alloy of uranium and fissium. 1
However, for the IFR application it is essential to recycle plutonium, and the best plutonium-bearing alloy
for performance under high irradiation is U-Pu-Zr. The role and accomplishments of the EBR-II reactor as
an IFR test bed are discussed in Chapter 6.
Another key feature of the IFR concept is pyroprocessing, a fuel processing method that utilizes high
temperatures, molten salt, and molten-metal solvents. Pyroprocessing is advantageous for metallic fuels
because the product is a uranium-plutonium metal alloy that is suitable for immediate fabrication into new
fuel elements. Direct production of this metal alloy avoids the expensive and cumbersome chemical
conversion steps that are used in the conventional PUREX aqueous-solvent extraction process. Further, it
assures that separated plutonium is never present in the fuel cycle.
The most important step in the IFR pyroprocessing is electrorefining, which recovers the valuable fuel
constituents, uranium and plutonium, and removes most of the fission products. In the electrorefining
operation, uranium and plutonium are selectively transported from an anode to a cathode, leaving impurity
elements (fission products) either in the anode compartment or in the molten-salt electrolyte. A notable
feature is that the minor actinide elements (americium, neptunium, curium) necessarily accompany plutonium
through the entire process.
Over the past few years, an extensive series of electrorefining experiments has been completed. Uraniumplutonium alloy has been successfully processed in small-scale experiments. Large-scale experiments are
ongoing, so far using only uranium metal because of security limitations on the amount of plutonium that
is allowed on the Argonne National Laboratory's Illinois site. Development of the pyrometallurgical
processing technology is discussed in Chapter 7.
Solid technical accomplishments accumulated year after year in all aspects of the IFR development program.
Along with that progress it becomes increasingly clear that IFR could meet the fundamental requirements
1 "Fissium" is an invented term referring to the nonvolatile fission products (mostly noble metals) that accompanied
the uranium in the early EBR-II recycle process.
6
C.E. Till et al.
of a next-generation reactor: efficient utilization of resources, inherent safe~ acceptable waste management,
and compatibility with rigorous safeguards against nuclear weapons proliferation.
FIRST REQUIREMENT: EFFICIENT UTILIZATION OF RESOURCES
The next generation of reactors must be capable of meeting large electricity demands efficiently, demands
that are a substantial and growing fraction of the global energy needs. Rising concern about the greenhouse
effect and other environmental threats provides motivation to be careful in formulating the specifications for
the energy supply options for the next generation so that they can contribute meaningfully to reduced reliance
on fossil-based energy.
"Efficient utilization" does not mean what it used to mean. In the nuclear field, the principal resource is
natural uranium, which is 99.3% 23SU and 0.7% 235U. Plutonium, depending on how it is handled, can be
either a hazardous by-product or an intermediate stage in the use of the uranium: a catalyst, in a sense, for
the consumption of 235U. Not m ~ . years ago, when there was concern that we were running out of uranium
ore, efficiency meant exploiting 23SU before the 235U was gone. This led to high priority on a breeder
reactor, to build up the world's supply of plutonium for use as such a catalyst (AEC, 1967). That has
changed. The end of the Cold War is releasing weapons plutonium that must be dealt with, and stocks of
unprocessed spent nuclear fuel around the world are growing rapidly. Political forces in many of the
industrialized countries (including the U.S.) have restrained the expansion of energy production, arguably
with resulting economic stagnation. Tiffs blockage has dramatically slowed the growth in electrical capacity,
and the previously assumed necessity for nuclear recycling to conserve uranium reserves has been pushed
off for decades.
Combined, these factors have transformed concern over running out of uranium ore into concern over a world
glut of plutonium (currently estimated at about 1000 tonnes and growing at about 70 tounes per year)
(Albright et al., 1993), which is seen as an environmental and proliferation threat. None of these
considerations detracts from the simple need for efficient utilization of resources. "Efficient utilization" now
implies making good use not only of available uranium ores, but also of the plutonium now on hand, while
minimizing both (a) the waste to be returned to the environment, and (b) the other environmental disruptions
that go with exploiting irreplaceable resources.
Today, the preponderance of the world's industrial and commercial energy comes from burning fossil fuels,
which for cons have been storehouses of vast quantities of hydrocarbons. Little is known about the near-term
sensitivity of the earth's ecosystems to the increasing amounts of CO 2 inevitably released to the atmosphere
as this material is burned. Some calculations suggest that massive conversion of hydrocarbons to CO 2 could
significantly affect the oxygen balance in the atmosphere. Some models predict that continuation of the CO2
increases currently being observed will lead to significant climate changes that will disrupt the ecological
balance. The case for an impending ecological disaster, however, is not conclusive, since currently
unidentified compensating processes that reduce the excess CO 2, returning some of the oxygen to the air, will
likely arise. What we do know is that atmospheric CO 2 is currently increasing and already has reached levels
far above those that have characterized the last 10,000 years. Since by the time climatic effects of increased
atmospheric CO 2, if any, become evident it will be too late to do anything about them, it seems prudent to
do what we can to minimize excess CO 2 emissions.
Nuclear power is the only alternative currently available to supply enough energy to have an impact on the
global trend in CO 2. To deploy nuclear power on a scale sufficient to influence global CO 2 levels will
require serious attention to the efficient use of nuclear resources.
The integralfast reactor
7
It has been suggested that more uranium can be found if only we pay more or look harder (Chow, Solomon,
1993). But without advanced fuel cycles, the picture will never change much overall: every million tons of
U308 used adds only a few more years and leaves behind another 1000 tons of plutonium (Till, 1994).
Several nations employing nuclear power are already well along in their programs to recycle their fuel, and
eventually they will do so in fast reactors. The energy payoff in the end is just too great not to. Economics
today may point this way or that, but the factor of 100 or more increase in energy that is possible from
recycle will inevitably determine national policies. Provision for future energy needs is at the heart of the
whole plutonium management issue.
We have what must be the simplest question ever asked of society and its decision makers: Do we take this
valuable resource and use it for the good of mankind and our comfort, or do we leave it in the environment
as a poison and an invitation for mischief?.
SECOND REQUIREMENT: INHERENT SAFETY
The next-generation reactor should have inherent passive safety characteristics and should also be simple to
operate. The metallic fuel of the IFR promises an excellent degree of inherent safety. Its safety
characteristics are better across the entire spectrum from normal behavior to postulated severe accidents than
those for a reactor fueled with conventional oxide fuels. The inherent safety features of the IFR type of
reactor preclude any significant damage under generic anticipated transient without scram, such as loss of
flow without scram, loss of heat-sink without scram, and transient overpower without scram. Those are
events that lead to very serious accidents with pressurized systems (light-water-cooled reactors--LWRs) with
oxide fuel.
The inherent safety potential of metallic fuel was demonstrated by two landmark tests conducted in EBR-II
on April 3, 1986 (see Chapter 6 and Planchon et al., 1987). Those tests demonstrated in a very concrete way
what can be done with liquid-metal cooling and metallic fuel to achieve inherent, wide-ranging safety
characteristics (see Chapter 4).
A benefit that was almost unanticipated arises from the improvement in the inherent response characteristics.
In traditional nuclear power plants, safety is assured by complex, highly-engineered safety and emergency
systems. Approximately 80% of all equipment in a traditional nuclear power plant contributes nothing to
power generation; it is there only to respond to off-normal and accident situations. These systems must be
extremely reliable, and almost all (an estimated 90%) of maintenance and inspection time is devoted to them.
Most of these emergency response systems are unnecessary in the IFR. The safety attributes and the
implications of the self-regulating characteristics of the IFR are discussed in more detail in Chapter 4.
THIRD REQUIREMENT: WASTE MANAGEMENT
Conservation of resources is an important consideration for the longer term, but a more pressing motivation
to recycle comes from the fact that there is no other disposition option. The only serious alternative is burial,
which has a seductive aura of simplicity and finality. However, that idea greatly worries arms-control
specialists, who realize that burying plutonium, in whatever form, creates "plutonium mines"; i.e., deposits
of concentrated plutonium, whose desirability for weapons increases as isotope-separation technology
improves and as the short-lived radioactivity decays.
The environmental acceptability of burying spent fuel is also being publicly questioned. The following
quotation, paraphrased only slightly, is from an article recently published in the New York Times Magazine
(Erikson, 1994):
C. E. Till et al.
This notion that one can actually see across a span of 10,000 years, a period twice as long as all
recorded history, really is incredible. The most mature and accurate scientific report should be: We
do not know, we cannot know, and we dare not act as though we know. Federal policy has been
to assure that waste management problems shall not be deferred to other generations. Geological
burial, at first glance, anyway, seems like the ideal way to accomplish this, since it removes the
wastes from the environment and solves the problem once and for all. But in many ways such
entombment does just the opposite. We are not taking the problem out of their hands as much as
we are taking the solution out of their hands.
There seems to be a consensus developing, or at least a politically dominant view, that there is no ultimate
disposition for thousands of tons of plutonium; that there can be no permanent, end-of-the-problem, once-andfor-all solution; no solution whereby we can wash our hands of the problem and turn to something else. If
this does become the prevailing view, "ultimate disposition" will mean perpetual custody of growing
quantifies of economically unproductive plutonium.
Effective management of plutonium, on the other hand, involves controlling the amount and nature of the
plutonium in a regime in which the total plutonium inventory can be reduced, maintained, or increased,
purely as a matter of policy, to meet energy needs. Today's reactors will not do this, but the IFR can
because it has efficient recycle and a hard neutron spectrum that fissions all actinides and all plutonium
isotopes without distinction.
If the residual waste which must be disposed of contains essentially no transuranics, the burden of disposal
is greatly simplified. In particular, plutonium should not leave the system as waste that itself must be
managed. Recycling the minor actinides (Np, Am, Cm) is required to minimize long-term ecological and
environmental concerns. If recycling can be made simpler and cheaper, economics will push in the desirable
direction, with energy value and avoided costs of alternatives driving toward what should be done anyway.
The search for precisely these characteristics has defined the goals of the IFR development program. Highlevel nuclear waste is composed of three major constituents: uranium, fission products and transuranic
elements, which result from neutron capture. In a time span of the order of a few hundred years, the fission
products decay enough that their radiological risk factor drops below the cancer risk level of the original
uranium ore. Some of the transuranic isotopes should not be left with the waste because they have very long
half-lives and their radiological toxicity, although small after about 500 years, remains orders of magnitude
higher than that of the fission products for tens or hundreds of thousands of years. Their acceptability as
a buried waste relies on their insolubility and immobility in most geologic environments. Therefore, there
is a strong incentive to separate actinides and recycle them back into the reactor for in-situ fissioning as a
means of improving confidence in the safety of disposed wastes. Early ideas on how to recycle and destroy
long-lived nuclear wastes were uniformly judged to be economically infeasible (Croft et al., 1980). The IFR
and its metal fuel cycle effectively reverse this conclusion.
The IFR method of recycle is based on simple pyrochemical processing that involves only a few steps. It
gives a product that is ideal fuel for the fast reactor, although composed of all the actinides in spent fuel:
plutonium, minor actinldes, and uranium. The IFR pyroprocess cannot fully separate plutonium from the
other constituents. The "fresh" fuel product is, in fact, always highly radioactive and self-protective in the
safeguards sense. All the processes are simple enough to be easily controlled remotely, so the self-protecting
nature presents no operational disadvantage. The fast spectrum fissions all plutonium and minor actinide
isotopes; hence, the reactivity of the isotopic mix does not degrade as it does in thermal spectrum recycle.
In contrast to LWR MOX recycle, the IFR recycling can continue until the fuel itself is gone. There are
essentially no minor actinides and no plutonium in the waste. Therefore, the waste repository needs no
safeguards against diversion to weapons use, and the waste has a limited radiological life.
The integral fast reactor
9
Even though the IFR recycle process removes the very long-lasting components from reactor waste, there
still is a residue of fission products that remain highly radioactive for decades and take several hundred years
to decay away. This means that geologic repositories will still be needed, but the fact that there is neither
plutonium nor significant radioactivity that lasts for millennia in the waste should have a significant impact
on the steps needed to assure that the high-level waste is contained for its lifetime.
Effective waste management does not end with the recovery and recycle of troublesome actinides: effluents
from normal operation must also be controlled, and the remaining materials must be processed into a waste
form that is acceptable for disposal. Both of these aspects are included in the IFR development envelope,
discussed in Chapter 8. The basic conclusion is that there appears to be no reason that an IFR system,
including both the reactor and its associated fuel cycle facility, cannot be operated in a practical manner as
a zero-release2 plant. Nothing need leave the site except energy, heat, and engineered waste products.
Perhaps the most significant application of IFR technology is its extension to the processing of spent LWR
fuel. Pyrometallurgical processes are being developed to extract the long-lived transuranics from spent LWR
fuel for use as feedstock for the IFR fuel cycle. As in the IFR fuel cycle itself, these are non-aqueous
processes that do not yield any directly weapons-usable material and are fully compatible with effective
safeguards. An acceptable technology for recovering actinides from LWR spent fuel has a double advantage.
First, the waste disposal concerns, as discussed above, are reduced, while the effective capacity of the
repository is increased; and second, a very large supply of startup fuel for IFR systems is available at the cost
of extraction. This leads to entirely new concepts of managing and safeguarding plutonium inventories.
Rather than an eternal burden of safeguards and environmental protection for immense inventories of waste
plutonium dispersed worldwide, LWR spent fuel immediately becomes a valuable energy resource
(McPheeters et al., 1993). The recycle technology, the waste processing and actinide recovery are planned
for demonstration in a small fuel cycle facility at Argonne National Laboratory's Idaho Site. This facility
is described in Chapter 9. The technology for LWR actinide recovery is discussed in Chapter 10.
FOURTH REQUIREMENT: SAFEGUARDS AGAINST PROLIFERATION
An immediate proliferation concern is the planned release of tonnes of plutonium from dismantled warheads
in the U.S. and in Russia. For the longer term, all plutonium, including that which could, in principle, be
separated from spent fuel in geologic repositories, will be a concern. Isotopic separation is becoming easier,
and it is even possible to make an explosive with isotopicaUy degraded plutonium. In 1962, U.S.
bombmakers confirmed this by detonating a device employing "reactor grade" plutonium. That test was part
of a program to develop and confirm calculational methods for predicting the performance of a nuclear
explosive as a function of isotopic composition (details of the test remain classified). Such unacceptable
solutions as launching the plutonium into the sun or diluting it in the ocean notwithstanding, transmuting the
plutonium by fission is the only real option for permanently eliminating its proliferation potential on a time
scale shorter than the 200,000 or so years required for its natural radioactive decay. All other options,
including burial, ultimately require perpetual safeguarding, with the attendant cost.
It is generally agreed that a "spent fuel standard" is a reasonable near-term criterion; i.e., the material will
be self-protecting by virtue of contained radiation comparable with that of discharged LWR fuel. Provided
this material cannot be easily separated, only reasonably straightforward safeguards provisions are required
(NAS, 1994). This spent fuel standard is met or exceeded throughout the entire IFR fuel cycle, which has
the added advantage that the whole cycle is colocated with the reactor complex, totally eliminating shipment
of spent fuel. If the system is fed with a more sensitive fuel (such as excess weapons plutonium), the
2 Zero-release implies that essentially no uncontrolled and unprocessed pollutants leave the site. There is, of course,
a discharge of waste heat.
C.E. Till et al.
10
material would be immediately denatured on receipt. Finally, since IFR fuel is metal it should be relatively
simple to blend plutonium from weapons with spent LWR fuel that has been reduced to metal; processes to
do so are being developed.
Plutonium in use is easily safeguarded; discarded plutonium is not. Plutonium in use serves the good of
mankind; discarded plutonium does not. Plutonium in use is not a threat to the safety or health of mankind
or the environment; discarded plutonium is.
If we deploy fast reactors that recycle their own waste and the spent fuel from thermal reactors as the IFR
does, the growth in the world's plutonium inventory of plutonium can be brought to a halt and then reversed.
Such a system could very quickly incorporate the world's existing inventory of separated plutonium, and,
within several decades, could absorb all the plutonium now accumulating in high-level nuclear wastes, acting
as an effective catalyst to realize the dream of the early pioneers in nuclear energy: a world with an
inexhaustible energy reserve (see Chapter 11).
Since there is essentially no discharge of plutonium to a waste stream, the safeguards concerns are limited
to the material in use. The fuel cycle is not only closed, but enclosed. Chapter 12 discusses the safeguards
provisions that would be used for such a facility. Proliferation scenarios involving both national reversion
and subnationai diversion are also considered in Chapter 12. It is shown there that an IFR infrastructure is
an unattractive source for a would-be proliferator, and would add nothing to the proliferation potential extant
today. In fact, since it constitutes a valid alternative to the PUREX reprocessing technology, deployment
of the IFR fuel cycle would greatly reduce the risk of proliferation of nuclear weapons.
CONCLUSION
We are at a critical junction in the development of IFR technology. Its nuclear performance is well
established, and the inherent safety potential has been demonstrated through actual plant tests at EBR-II, as
well as with experiments in the TREAT reactor. Demonstration of the complete fuel cycle, including waste
treatment, remains to be done.
REFERENCES
AEC (1967). Civilian Nuclear Power, The 1967 Supplement to the 1962 Report to the President, U.S.
Atomic Energy Commission.
Albright, D., E Berkhout and W. Walker (1993). World Inventory of Plutonium and Highly Enriched
Uranium 1992, Oxford University Press, Oxford.
Chow, B.G. and K.A. Solomon (1993). Limiting the Spread of Weapon-Usable Fissile Materials, RAND,
Santa Monlca, CA.
Croft, A.G., J.O. Blomeke and B.C. Finney (1980). Actinide Partitioning-Transmutation Program Final
Report I. Overall Assessment, Oak Ridge National Laboratory Report ORNL-5566.
Erikson, K. (1994). Out of Sight, Out of Mind, New York limes Magazine, 6 March.
DeGalassus, B. (1994). Perspectives on U.S. Plutonium Policy, International Policy Forum: Management
& Disposition of Nuclear Weapons Materials, Leesburg, VA, 8-11 March.
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INFCE (1980). International Nuclear Fuel Cycle Evaluation, International Atomic Energy Agency Report
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McPheeters, C.C., R.D. Pierce, D.S. Poa and P.S. Maiya (1993). Pyrochemical Methods for Actinide
Recovery from LWR Spent Fuel, Proceeding of the International Conference on Future Nuclear Systems." Emerging Fuel Cycles & Waste Disposal Options, p. 1094, Seattle, WA, 12-17 September.
The integral fast reactor
11
NAS (1994). Committee on International Security and Arms Control, Management and Disposition of Excess
Weapons Plutonium, National Academy Press, Washington, DC.
Planchon, H.P., J.I. Sackett, G.H. Golden and R.H. Sew (1987). Implications of EBR-II Inherent Safety
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Semenov, B.A. and N. Oi (1993). Nuclear Fuel Cycles: Adjusting to New Realities, 1AEA Bulletin 35,
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Till, C.E. and Y.I. Chang (1986). The Integral Fast Reactor Concept, Proceedings American Power
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