Status of Pre-Operating Tests for the Latest ABWR in Hamaoka Nuclear Power Unit No. 5

Kashiwazaki-Kariwa Nuclear Power Station Unit 6 and Unit 7 (K6 & K7) are the first advanced boiling water reactors (ABWR) in the world. Toshiba has been engaged in the design and construction of boiling water reactors (BWR) for Hamaoka Nuclear Power Station Unit 5 (H5) of Chubu Electric Power Co., Inc. and Higashidori Nuclear Power Station Unit 1 of Tohoku Electric Power Co., Inc. H5 has features of the simplified reactor coolant recirculation system including a reactor internal pump (RIP) and reduction in plant startup time using a fine-motion control rod drive (FMCRD). The H5 has been improved through additional modifications such as a reduction in the number of adjustable speed drives (ASDs) required by RIPs. This was managed through multi drive and the elimination of a shaft seal from FMCRDs by applying magnetic coupling. The basic performance of the modified FMCRD (S-FMCRD) has been verified by the joint study of Japanese operating utilities and vendors. In addition, various other tests are performed on the H5 to validate its actual component design during the manufacturing stage and pre-operation stage. Construction of H5 began in March 1999. Bedrock inspection was completed in May 2000, the reactor pressure vessel (RPV) installation was finished in July 2002, and power receiving was completed in December 2002. Currently, H5 is scheduled to start commercial operation in January 2005. Pre-operating tests began at the end of 2002. The utility systems test, like the MUWP (makeup water system), HVAC (heating, ventilation and air conditioning), etc, began two months prior to power-receiving, followed by both the RCCW (reactor building closed cooling water system) and RCWS (reactor building cooling sea water system) tests. The primary system pre-operating test, which is usually performed at the peak of the pre-operating test period, was completed by mid-February, 2004. Each test schedule was controlled and each test followed the predefined test plan. On the other hand, S-FMCRDs and control rods (CRs) were installed, followed by an RPV overpressure integrity inspection test conducted in September 2003. Following this test, RIPs and related control system confirmation tests was performed Subsequently, FMCRDs pre-operation test was planned to confirm performance levels. The modified design concepts, such as S-FMCRDs and multi drive ASDs for RIPs etc, were scheduled for verification during this phase.