Between MOX and a hard place
It costs more, it’s as
dangerous to make as a bomb, and burning MOX creates
almost as much plutonium as it gets rid of. Other than
that, it’s a great idea.
In September 2000, the United States and Russia signed an
agreement to dispose of 68 metric tons of weapons-grade
plutonium (34 tons each). The agreement called for 25.5
tons of U.S. plutonium and all of the Russian quantity to
be converted into a more diluted form suitable for use in
mixed oxide (MOX) fuel in commercial nuclear power
reactors. The remaining 8.5 tons from the United States
was to be immobilized—until the government decided in
2001 to burn that as fuel as well.
The MOX program elicited controversy well before Vice
President Al Gore and Russian Prime Minister Mikhail
Kasyanov made it official in 2000. Critics complained
that MOX jeopardizes reactor safety and does little to
actually reduce plutonium stockpiles, since spent MOX
fuel can be separated and the plutonium reused in bombs.
The plan, they said, affords terrorists or rogue states
greater opportunity to obtain plutonium. Plus, the
program is expensive—more than $6 billion to build MOX
fabrication facilities in Russia and the United States
and convert reactors to handle the new fuel. Experts
predict it could take 10 years to retrofit those
reactors, extending the disposal process for another
Three years of indecision and foot-dragging by both sides
has stalled the MOX agreement and done nothing to quell
the debate. And now, at least one alternate plan has
emerged: a thorium-plutonium fuel design being developed
in Russia with the support of private and government
funding from the United States. This new fuel promises
significant advantages over MOX, including lower costs, a
faster rate of plutonium usage, and greater proliferation
resistance (see sidebar).
With a potential alternative on the horizon, the high
cost of the MOX fuel plan, the dangers associated with
its production, and the slow progress it will make toward
reducing global stockpiles of plutonium make it timely to
ask: Isn’t there a better way? A closer examination of
MOX fuel economics and MOX experiences in other nations
clearly demonstrates its inherent limitations.
A brief history of MOX
MOX fuel is an integral part of the closed nuclear fuel
cycle, where plutonium is irradiated, reprocessed, and
reused. It is regarded as a stepping-stone toward
commercial development of the more efficient fast-breeder
reactor, which could create more plutonium fuel than it
To make MOX fuel, plutonium, in the form of plutonium
oxide, is mixed with uranium oxides and pressed into
ceramic fuel pellets that are loaded into seamless fuel
rods. The technology was pioneered by the United States
during World War II. The fabrication of MOX fuel is
considerably more complicated and more hazardous than
that of uranium fuel. Due to the extremely high
radiotoxicity of plutonium, it must be processed in
isolation: Protective barriers, including remotely
operated equipment, need to be built and maintained.
After the ceramic MOX pellets are encapsulated into fuel
rods, the handling of MOX fuel is essentially the same as
that of conventional uranium fuel.
MOX fuel demonstration programs began in the United
States and Europe in the 1960s. By the mid-1970s, the U.S.
nuclear industry was ready to implement a large-scale MOX
utilization program. However, in 1977, concerns over
plutonium being diverted to terrorist groups or rogue
states caused President Jimmy Carter to issue an
executive order that indefinitely deferred the
reprocessing of spent nuclear fuel. The administration
hoped that other nations would follow its lead and also
ban reprocessing. But the effect of the executive order
was to halt the development of MOX and fast-breeder
reactor technologies in the United States, while other
countries proceeded to implement fuel reprocessing in
their commercial nuclear programs. As a result, the
United States today faces a serious shortage of personnel
experienced in evaluating, designing, fabricating, and
irradiating MOX fuel.
The experience of U.S. fuel designers, fuel
manufacturers, and energy-producing utilities is based on
uranium oxide fuel—the type used in commercial U.S.
reactors. Working with MOX is entirely different than
working with uranium oxide. Scientists must consider
different safety, manufacturing, and performance
requirements with MOX, starting in the reactor design
process. Differences in nuclear characteristics mandate
new design strategies to deal with problems like control
rod considerations and local power peaking. For example,
important parameters such as the moderator temperature
coefficient or the Doppler coefficient (both of which
affect the stability of the core during accidents) are
more negative in a MOX core than in a conventional core,
and a MOX core operates with hotter fuel rods.
In addition, the thermal mechanical behavior of MOX fuel
is not as well understood as that of uranium oxide fuel.
The computer models used to predict the evolution of
uranium oxide fuel during irradiation have been
extensively benchmarked against data obtained from
examining irradiated commercial fuel elements. The data
from MOX fuel are much more sparse and were obtained
largely in experimental reactors.
One of the parameters calculated with fuel performance
codes is the amount of fission gas produced in the fuel
and the fraction of this gas that migrates outside the
ceramic fuel matrix. This parameter plays a very
important role in establishing the safety of the fuel:
The fission gas released by the ceramic pellets can exert
pressure on the cladding wall, and could potentially
cause the fuel rod to increase its diameter and block
coolant flow if the gas pressure exceeds the coolant
pressure. Because of uncertainty with MOX fission gas
release behavior at higher burnup, and the potential
impact of high fission gas release on plant safety, the
discharge exposure of MOX fuel is not allowed to be as
high as that of conventional uranium oxide fuel. Since
the higher the discharge burnup, the more economical the
fuel, MOX is less economical than uranium oxide.
During irradiation, the cladding barrier on some fuel
rods may breach, contaminating the coolant. Aggressive
programs by utilities and fuel manufacturers have
minimized the number of rods with breached cladding, but
the potential is a continual concern. To decrease dose
rates, utilities stop operations in mid-cycle to search
and remove failed rods at a significant cost. Because the
reliability and post-failure behavior of MOX fuel is not
as well understood as that of uranium oxide fuels, it
cannot be asserted that fuel failures will not have more
severe consequences than those that have already been
experienced. And that could mean higher operating costs.
The MOX manufacturing process is also more complicated
than that of uranium oxide fuels. A major concern is to
keep people separated from the plutonium until it is
encapsulated in sealed fuel rods. Effective barriers such
as glove boxes (closed containers with double-walled
gloves that allow operators to manipulate dangerous
substances from the outside) must confine the plutonium.
Fabricating ceramic pellets involves using oxidized
plutonium powder, and grinding operations create fine
dust particles. Both necessitate directionally controlled
airflow to limit the spread of airborne contaminants.
Automatic equipment must be used to manipulate fuel
samples for quality control verifications. The safe
storage of plutonium mixtures during fabrication requires
different containers to prevent criticality accidents.
The shipping containers need to be relicensed to account
for the presence of plutonium in the fuel rods. All of
these complications increase the cost of fuel
Commercial feasibility of MOX
The current price of uranium, in constant dollars, is
less than half the price it was 25 years ago, when the
economy of the MOX fuel cycle was being evaluated.
Projections for uranium demand have not materialized, and
discoveries of new sources of uranium ore, combined with
a worldwide overcapacity of enrichment facilities to
produce low-enriched uranium for standard light-water
reactors, have contributed to the collapse of uranium
prices. Many uranium mines have closed because prices are
Even if natural uranium cost $700 per kilogram more than
it does now, accounting for reprocessing and enrichment,
it would still be as cheap or cheaper than MOX fuel. The
production of commercial MOX fuel would need to increase
considerably for economies of scale to lower the
production costs enough to make its unit price
competitive with uranium. But the current consumption of
MOX fuel represents only about 2 percent of the fuel used
by nuclear utilities worldwide, and commercial prospects
for increased demand are dim based on recent developments
in Britain and Japan.
Japan has been the largest customer of MOX fuel. Until
recently, its interest in MOX was perceived by many as a
sign of a renaissance for the industry and the only
realistic new MOX market. The country’s energy strategy
aimed at using plutonium stockpiles to power all its
nuclear power plants, and Japan was even contemplating
building its own MOX fuel fabrication facilities.
However, numerous scandals and accidents over the last
four years have sparked an overwhelming public anti-MOX
In 1999, it was discovered that British Nuclear Fuels Ltd.
(BNFL), the British fuel manufacturer, had falsified
quality control data used to demonstrate the
acceptability of a shipment of MOX fuel to Japan. The
fuel was returned to Britain, and BNFL lost credibility
as a reliable supplier for the Japanese market. In
September 2002, Tokyo Electric Power Co. (Tepco), the
largest nuclear utility in Japan and the world’s
largest privately owned electric utility, admitted that
General Electric had found cracks in reactor core
components during routine maintenance work. Tepco
management kept this information secret for two years,
but General Electric reported its findings to Japanese
As a result, Tepco had to close 13 of its 17 nuclear
reactors, which had been supplying 44 percent of Tokyo’s
electricity. The company may still shut down the rest of
its nuclear fleet in order to perform additional safety
checks. Tepco has already announced that it is delaying
the irradiation of MOX assemblies indefinitely.
In a different type of accident, in September 1999,
workers in the Tokaimura fuel-processing facility
operated by the Japanese company JCO were exposed to
lethal doses of radiation due to a criticality accident.
The accident occurred because the company apparently
violated safety procedures in order to meet increased
production requirements, and workers were allowed to mix
batches of uranium, enriched to 18 percent uranium 235,
into an unsafe geometry. Since the higher level of
uranium 235 enrichment is required by fast-breeder
reactors, the accident in Tokaimura may cause Japan to
abandon its breeder program.
Problems in the MOX business are not limited to Japan.
Belgian MOX fuel manufacturer Belgonucleaire has been
having troubles since 1994, when the Belgian government
decided to stop reprocessing for MOX. In 1998, a national
court denied Belgonucleaire a license to build another
MOX fuel fabrication plant. In 1999, after BNFL falsified
data on MOX fuel shipped to Japan, Belgonucleaire was
subjected to numerous reviews and technical audits. The
recent Tepco incidents have eliminated a large potential
market and may challenge the company to keep its MOX fuel
fabrication plant and other facilities operational.
France has a well-established MOX program, yet it faces
problems associated with MOX fuel’s limited burnup
capability, the high cost of fabrication, and the MOX
troubles in Japan, which France was hoping would be a
large new market for French global energy concern Cogema.
The French nuclear regulator limits the maximum number of
MOX rods in each assembly, the maximum plutonium content,
and the discharge burnup. These safety limitations make
MOX fuel less economically attractive than uranium oxide
fuel. In June 2001, Electricité de France, the French
national utility, submitted a request to the licensing
authorities to relax the MOX limits, but at the time of
this writing, the limitations had not been lifted.
In Germany, after spending approximately $700 million
building a MOX fuel fabrication plant in Hanau, nuclear
utilities and Siemens, the German fuel fabricator,
decided to dismantle it completely because of concerns
about its future, given the anti-nuclear stance of the
German government. The dismantling of the plant began in
In Britain, BNFL recently completed and opened a new MOX
facility at Sellafield, spending upward of $400 million.
No fuel orders are being placed at the new plant, and the
latest shipment of BNFL’s MOX fuel destined for Japan
was returned due to the Tepco scandal. Additionally,
negotiations to sell six BNFL reactors and a MOX
reprocessing plant to British Energy failed due to that
The economics of getting the U.S.-Russian MOX fuel
agreement off the ground are proving just as questionable
as existing MOX operations. The cost of the U.S.
disposition program is estimated at $4 billion, while the
projected cost of the Russian program is between $1.8
billion and $2.5 billion. Many experts believe that the
combined costs will escalate from the projected $5.8–6.5
billion to more than $10 billion. The Russian government
agreed to the plan only if the U.S. government, with
assistance from other countries in the Group of Eight (G8)
most industrialized nations, funded the project. The
United States has pledged $400 million toward Russian
costs, and another $400 million is expected to be donated
from other nations, although the June 2003 G8 summit in
Evian, France, ended without any mention of the MOX
project, much less a pledge to fund it.
In June 1999, the Energy Department awarded a $130
million base contract to Duke Cogema Stone & Webster
(DCS), a consortium of companies equipped to support
Energy’s mission to dispose of surplus plutonium. Under
the base contract, DCS was to provide full-scope services
including design, construction management, operation, and
deactivation of a MOX fuel fabrication facility.
Construction was scheduled to begin this year at the
Savannah River Site near Aiken, South Carolina, but has
been pushed back to 2004. And at the time of this
writing, the construction permit had not been issued.
Given the antagonistic attitude between the U.S. and
French governments during the war in Iraq, it is unclear
whether Energy will want to continue its association with
Cogema in this project, in particular when BNFL was also
one of the bidders for the U.S. and Russian MOX contracts.
Changing contractors would cause further delays and raise
Other unresolved issues between the United States and
Russia could also delay the program’s implementation.
Because of Russia’s sensitivity to maintaining the
secrecy of the isotopic composition of its weapons-grade
plutonium, the country plans to mix it with reactor-grade
plutonium before making it available for the program.
Such a plan creates verification problems. According to
Michael Guhin, U.S. fissile material negotiator for the
State Department, the Russians and Americans have not
agreed on a process to verify that the plutonium for the
MOX program actually comes from weapons stockpiles. This
means that billions of dollars could be spent to dispose
of the wrong plutonium.
In addition, Russia has not agreed to join the Vienna
Convention on nuclear liability, a key U.S. issue. The
United States expects Russia to commit to pay for any
liability associated with the plutonium disposition
agreement and to contribute cash toward the MOX program,
but Russia has not yet agreed to these terms.
MOX fuel, although a technically viable solution for the
disposition of excess weapons-grade plutonium, is not
without problems. The lack of significant experience in
the United States with fabricating and irradiating MOX
fuel, its high cost, the recent negative experience with
MOX fuel in Japan and elsewhere, and the delays in the
implementation of the program indicate that parallel
alternative advanced fuel designs should also be
evaluated for the disposition of U.S. and Russian
zpět na úvodní