Current status toward the reoperation of JMTR

Kaminaga, Masanori  ; Ooka, Makoto; Ishihara, Masahiro ; Kusunoki, Tsuyoshi ; Araki, Masanori

JMTR is a light water cooled tank type reactor with 50 MW. From its first criticality in March 1968, the JMTR has been utilized for fuel/material irradiation examinations of LWRs, HTGR and fusion reactor as well as for RI productions. In August 2006, the JMTR operation was once stopped in order to have a check & review for the reoperation. As a result of the national discussion, the JMTR was determined, finally, to restart after necessary refurbishment works. The refurbishment works were started from the beginning of JFY 2007, and replaced were motors of primary and secondary cooling pumps, nuclear instrumentation system and so on. The refurbishment works were finished in March 2011. Unfortunately, at the end of JFY 2010 on March 11, the Great-Eastern-Japan-Earthquake occurred, and functional tests before the JMTR restart, such as cooling system, reactor control system and so on, were delayed by the earthquake. Moreover, a detail inspection found some damages such as small cracks in the concrete structure. Consequently, the restart of the JMTR was delayed from June 2011 to this year. A seismic influence evaluation after the earthquake disaster was carried out. The seismic influence evaluation results has been reported to the regulatory agency. Validity of the seismic influence evaluation results will be evaluated by the Nuclear Regulation Authority (NRA). JMTR will be re-started after the validation evaluation by the NRA. JMTR will be operated for 20 years. Expected utilization fields will be a safety research of LWRs for materials/fuels, basic research for nuclear engineering such as HTGR fuels/materials, fusion reactor materials, industrial use such as production of Mo-99 for medical use, and education & training of nuclear scientists and engineers.