Recent Shifts in Monju Policy
The government is attempting the continued use of Monju for
the nominal purpose of reducing the volume of radioactive waste
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Rally against the Monju Reactor, 2013
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Introduction
The fast breeder reactor Monju
has been in a state of shutdown since the sodium coolant leak accident
in December 1995. The reactor managed a zero-output trial restart on
May 2010, but in August of the same year an in-vessel transfer machine,
part of the equipment for fuel replacement, fell into the reactor,
which is still shut down. The policy indicated in the Democratic Party
of Japan (DPJ) government’s Innovative Strategy for Energy and the
Environment (2012) was to bring the research to an end after
experimental operation of the reactor for about five years followed by
a summary of the outcomes, but in September 2013 the Abe administration
overturned this research termination by coming out with a Monju
Research Plan.
Monju Research Plan
The research plan was put together by the Atomic
Energy Science and Technology Commission Monju Research Plan working
group (chaired by Hajimu Yamana) under the supervising ministry,
Ministry of Education, Culture, Sports, Science, and Technology (MEXT).
According to the DPJ government’s Innovative Strategy for Energy and
the Environment, “With international cooperation, Monju will be used to
summarize the outcomes of fast breeder reactor development and carry
out research aimed at reducing the volume of long-lived radionuclides
in nuclear waste, and a research plan with a limited term of years will
be formulated and implemented for that purpose, the research being
terminated once the outcomes have been confirmed.” The Strategy also
stated, however, that, “Treatment technology for spent nuclear fuel for
the purpose of reducing the volume of nuclear waste products, and
R&D on burner reactors, will be promoted.”
Until now, the breeder reactor has been held up as
the kind of reactor resource-poor Japan should be aiming for, but the
content of the plan shown above indicates no outlook for the practical
realization of the fast breeder. What it does indicate is a gradual
switch to nuclear waste volume reduction as a means of continuing the
research. The breeding function is unnecessary for waste volume
reduction, and thus there seems to be an awareness of a changeover from
a fast breeder reactor to a fast reactor. Furthermore, Japan is also
participating in the international R&D program for the fourth
generation reactor (GEN-IV). It would seem that the changeover from the
fast breeder reactor to the fast reactor is taking place bit by bit
without any open decision-making. The Research Plan uses the ambiguous
format “fast breeder reactor/fast reactor.” In the sponsor’s greeting
at “The International Forum on Peaceful Use of Nuclear Energy, Nuclear
Non-Proliferation and Nuclear Security,” held on December 3, 2013, the
President of the Japan Atomic Energy Agency (JAEA), Shojiro Matsuura,
spoke of Monju as a “prototype fast reactor.” Since the head of the
organization that has constructed and operated Monju uses this
expression, we may say that the changeover to a fast reactor is now
clear.
The finalized “Research Plan” gives approximately
six years as the “period for summarizing outcomes.” After operating the
reactor for four months, a period of eight months is then provided for
reactor maintenance along with data collection and analysis in
accordance with a list of desired outcomes, one year being one “cycle.”
Therefore, after a scheduled one-year performance test operation, it is
intended that the reactor will be put through five full-fledged
operational cycles.
After the results from the six-year study are
compiled, a decision will be made on whether or not to continue the
Monju research, based on energy policy priorities and international
conditions.
It is said that the Monju facility will be utilized
for research on reduction of the volume of nuclear waste, but because
in actuality the reactor was shut down for a long period, it contains
much americium, so in a sense this only amounts to a positive-sounding
expression for the necessity of using aging fuel. That is to say,
since considerable time has passed since the plutonium that was going
to be used as the fuel for Monju was reprocessed (plutonium
extraction), they have little choice but to use fuel that has a high
americium content. Theoretically, americium undergoes nuclear fission
by bombardment with fast neutrons (1 MeV or greater), so this is one of
the research issues that is said will be verified at Monju.
It is doubtful whether sufficient nuclear fission
would take place in a fast reactor. The energy of neutrons in a reactor
is not uniform, and depending on the circumstances, americium may
absorb neutrons without undergoing fission. In that case, americium will change into a longer-lived radionuclide.
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The fissile material in the Monju fuel, Plutonium-241, decays naturally to Americium-241 at a half life of about 14 years.
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Organizational self-reformation
A research plan has been made, but is the organizational system capable of implementing it?
The accidental sodium leak and fire in 1995 was the
result of a simple design error in the sheath of a thermocouple (for
which Toshiba was responsible) used for measuring the temperature of
molten sodium flowing through the pipes. Sodium leaked out by an
unanticipated route, resulting in a fire. The accident involving an
in-vessel transfer machine in 2010 was the result of a failure to
enforce measures to prevent rotation of a device used for grasping and
lifting fuel assemblies within the reactor, and it was also a simple
design error on the part of Toshiba. After the 1995 accident, thorough
safety inspections including confirmation of facility conformity to
drawings and specifications were conducted, but they failed to detect
the simple design error in internal relaying equipment. Problems
occurred in 2010, just prior to restarting the reactor for a
performance test run. These included substantial errors and failures to
check the sodium leak detection equipment. Improvements should have
been made by investigating the fundamental causes of these problems,
but 14,316 subsequent inspection failures have come to light since late
2011.
Because of the lack of a suitable organizational
system for running Monju, JAEA conducted its own analysis of the
fundamental factors causing trouble and published Self-reformation –A
Path Toward Rebirth–. Self-reformation was compiled by Shojiro
Matsuura, who assumed presidency of the JAEA in May 2013. Matsuura
previously headed the former Japan Atomic Energy Research Institute and
was chief of the Nuclear Safety Commission from 2000 to 2006.
The JAEA has analyzed the fundamental causes of the
accidents and problems thus far and has made organizational reform
efforts, but even so, accidents and problems have continued to recur.
Their analysis of the fundamental causes is nowhere to be seen in
Self-reformation, and the recommendations for dealing with these issues remain those that were formerly made.
A general safety inspection tracing back to the
design documents was conducted only once during the general safety
inspections at Monju after the accident in 1995, and has not been
conducted since then. Considering the current situation in which the
knowledge of the people who were involved initially is not being passed
along, the author believes that a new general safety inspection with a
retrospective review of the design documents is now necessary again.
Monju was developed using the so-called “convoy
system” method. That is to say, the former Power Reactor and Nuclear
Fuel Development Corp. was in charge of dividing up orders, with
primary equipment orders (nuclear reactors) going to Mitsubishi Heavy
Industries, secondary orders (sodium coolant systems for transferring
heat from the primary equipment to the tertiary) to Toshiba, and
tertiary orders (water and steam equipment) to Hitachi, with each of
these companies responsible for the design, installation and
maintenance of their respective equipment. Each of these manufacturers
further subcontracted their work, entrusting actual maintenance work to
the respective companies that had installed the equipment. This kind of
order placement structure makes coordination among the manufacturers
difficult. In addition, the people initially involved in the ordering
side of the system as well as the people involved substantially in the
design and installation among the manufacturers are mostly at
retirement age, so technical knowledge and know-how will not be
sufficiently conveyed. The outlook for success of the reformation is
extremely dim.
Fast breeder reactor (FBR)
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Breeding plutonium to enhance energy security
Focus on economic efficiency
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Fast reactor (FR)
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No plutonium breeding
Focus on reduction of volume of radioactive waste
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The Nuclear Regulatory Commission’s Response
The research plans and self-reformation all
presuppose the renewed operation of Monju. From September 2013, new
standards came into effect, and standards for experimental reactors are
tentatively in order. Even so, however, they do not require the
installation of an emergency reactor core cooling system at Monju. The
risk of a runaway nuclear accident at Monju has been pointed out, but
the standards for accidents peculiar to fast breeder reactors are
“under consideration.” Renewed operation with no standards in place
would be unthinkable.
Meanwhile, the Nuclear Regulatory Commission is
conducting an inspection of the fracture zone at the Monju site. It is
taking the position that it is necessary to cover an area greater than
that examined in the earthquake resistance ‘back check’ conducted by
the JAEA in 2008. The JAEA maintains that the fracture zone at the site
is not active, but the standards under the new regulations require
consideration of whether or not slips could occur in association with
movement of the main fault. These considerations will take time, so it
will probably be at least several years before performance tests can
begin at Monju.
If that is the case, 30 years will have passed since
the Monju reactor was built. Such an old reactor, combined with such
dubious conveyance of technical knowledge would mean that operation of
this nuclear reactor would entail extremely high risks.
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Location of Monju and nearby nuclear power plants
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We Need a Comprehensive Appraisal of Monju!
First of all, a comprehensive appraisal is needed
regarding the suitability of restarting the Monju reactor, the
possibility of reducing the amount of nuclear waste, and whether or not
this research is a suitable use of government funds. This appraisal
needs to include a comprehensive assessment of the propriety of
spending several trillion more yen on fast breeder reactor R&D when
two trillion yen have already been invested, including into Monju, in
the unfulfilled hopes of practical use. It must also consider the
danger of a serious accident at Monju, given those that occurred at the
nuclear plants in Fukushima. The fact that the MEXT is calling together
scholars to promote Monju and drawing up research plans constitutes a
serious problem.
Hideyuki Ban (Co-director of CNIC)
[Notes]
Monju research plans (in Japanese):
http://www.mext.go.jp/b_menu/shingi/gijyutu/gijyutu2/061/shiryo/1339409.htm
The Japan Atomic Energy Agency’s reformation plans (in Japanese):
http://www.jaea.go.jp/02/press2013/p13092601/index.html
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