Power Line
The Federation of Electric Power Companies of Japan Vol.26
March 2005

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.