| Ryoukichi Kanai | Nuclear Systems Div., Power & Industrial Systems, |
| Kaoru Shinohara | Nuclear Systems Div., Power & Industrial Systems, |
| Jun'ichi Numa | Nuclear Systems Div., Power & Industrial Systems, |
| Naohisa Yabuki | Nuclear Systems Div., Power & Industrial Systems, |
Constructed for enhanced safety, reliability and cost-effectiveness, Tokyo Electric Power Company's Kashiwazaki-Kariwa units 6 and 7, the world's first advanced boiling water reactors (ABWRs), have continued to operate stably since they first entered commercial operation. Now at the end of November 2000 with unit 6 in its 4th in-service cycle and unit 7 in its 3rd cycle, both plants have demonstrated high levels of operational performance. The new systems and equipment developed for the ABWR units (reactor internal pumps, and fine motion control rod drive mechanism) have also exhibited excellent dependability. Unit 6 which entered service in November 1996 has now been subjected to 3 annual inspections, while unit 7 which entered service eight months later in July 1997 has had 2 inspections. The first periodic inspection took 55 days, but subsequent inspection outages were reduced to 44 days for unit 6 and 45 days for unit 7, thus contributing to the high performance of the two reactors. It should be possible to reduce the inspection outage length to 30-35 days in the future, which will boost the cost-effectiveness of the plants even further. At the same time, the occupational radiation exposure during annual inspection has been held to a very low level; during the first inspection of unit 7, for example, an excellent exposure figure of about 150 man·mSv was obtained. The periodic inspection results confirm that the operational performance of the ABWR units have met and exceeded the performance targets that were set when the reactors were designed and deployed.
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The Hitachi Hyoron (Japanese Only) |
Annual Inspection, ABWR, Radiation Exposure, FMCRD, Reactor Internal Pump
