Another Step Towards Full-Scale Operation
of the Reprocessing Plant
UNDER THE AEGIS of the Atomic Energy Commission of Japan, the Long-Term
Planning Council, which is presently deliberating on Japan's future
nuclear policy, reaffirmed on November 12, 2004, to continue the
current basic policy of reprocessing spent fuel and utilizing recovered
plutonium, uranium and other materials. This decision was made after
the Council's discussion about the optimal setup for the nuclear
fuel cycle, and the Council's Technology Subcommittee's deliberations
on the discussion results.
Since then, Japan Nuclear Fuel Limited (JNFL) concluded a safety
agreement regarding its Uranium Test at the Rokkasho reprocessing
plant with Aomori Prefecture, Rokkasho village and neighboring municipalities.
The Uranium Test started on December 21, 2004 at the Rokkasho plant,
and utilized uranium to check the performance of the facilities
and equipment, detect nonconformity in its early stages, improve
technology and enhance operating procedures, all in preparation
for full-scale operations slated for fiscal 2006.
Uranium Test:
Outline and Purpose
JNFL's Rokkasho village reprocessing plant has carried out water-flow
tests and chemical tests using chemicals such as nitric acid. Most
of this testing has already been completed, and efforts have been
made to improve the safety of the facilities through the adjustment
of equipment and the detection of nonconformity.
On December 21, JNFL began its Uranium Test which focuses on the
utilization of the properties of uranium. In order to provide a
realistic simulation, JNFL utilizes depleted uranium, which contains
a lower percentage of uranium 235 (which is fissile) than natural
uranium. The handling of depleted uranium is easy because of its
lower radioactivity level and its difficulty to reach criticality
under any conditions. Therefore, workers can deal with equipment
nonconformities on the spot, should any be detected. JNFL utilizes
uranium in various forms (powder, solution and simulated fuel assembly)
in accordance with reprocessing procedures.
Performance of the Uranium Test
The reprocessing plant consists of more than twenty buildings,
and the Uranium Test first begins with (1) the adjustment of individual
equipment units installed in the buildings. Tests are then performed
in the following order: (2) a system test to verify the systems
performance of multiple equipment units; (3) a comprehensive
system test which comprises the running of the entire equipment
groups composed of several systems, in order to determine the operating
characteristics of interacting systems; (4) a disturbance test to
evaluate the reaction of the whole facility in the event of an emergency
shutdown;
(5) an integrated building test to verify the startup of all equipment
in an entire building, and the course of the operating process,
including rated operation and shutdown; and (6) a general validation
test to provide final confirmation of the whole plant?s readiness
for the Active Test using real spent fuel.
Safety and Environmental Measures
JNFL has situated its uranium treatment facilities in small rooms
(cells) isolated by thick concrete, and maintains a lower air pressure
in these cells than that of the outside atmosphere to prevent air
escape. Lined pans have been provided for those facilities dealing
with uranium solutions, based upon the assumption that uranium solutions
might leak. Gaseous and liquid waste products will be generated
during these tests, and such waste will be handled properly and
released only after monitoring and analysis. Regular environmental
monitoring will be conducted to ensure that waste management is
performed adequately.
Lessons Learned
In acknowledgment of the problems experienced by leading facilities,
such as COGEMA in France, JNFL has prepared a booklet of case studies
citing possible problems that might occur during the Uranium Test,
and offering guidelines to solve such problems.
Safeguard System at Rokkasho Plant
Japan has implemented peaceful use of nuclear energy in visible
forms over the last 50 years. More specifically, the nation complies
with the bilateral atomic energy cooperation agreement including
the United States, IAEA safeguards and the Nuclear Non-Proliferation
Treaty. The Rokkasho Reprocessing Plant is under round-the-clock
monitoring by IAEA to ensure no uranium or plutonium is diverted
for producing nuclear weapons. The facility is also equipped with
safeguard system of the highest level.
The Uranium Test represents an important step in establishing the
nuclear fuel cycle. As electric power suppliers, we are committed
to do our utmost to facilitate the smooth progress of nuclear fuel
cycle operations, including the reprocessing work in Rokkasho village
and MOX use in thermal reactors, consistent with the basic principles
of the national energy policy and the greater principle of securing
safety. |