Status of the Process Computer in the Tohoku Electric Power Co. Ltd. Onagawa nuclear power plants Units 1 & 2
2000/1/1 11:00
Agency of Natural Resources and Energy, MITI
1. Outline of the Incident
At 00:02 on 1 January 2000, in the No. 1 & 2 process computers of the Onagawa nuclear power plant (NPP) of the Tohoku Electric Power Co. Ltd., an alarm (Process Computer Detector Failure) was actuated and at 00:12 the alarm had been cleared automatically and normal operations resumed. During that time, data compiled in monitoring stations was not sent to the process computer, but after the resumption the system is functioning normally. Whether the incident was related to Y2K is currently under investigation.
The data itself was saved properly into a radiation management computer installed in the service building.
2. Data not Transmitted
The following data from the monitoring facilities:
(1) Monitoring stations (Tohoku Electric Power Co., Ltd. has four stations, Miyagi Prefecture has six stations)
(2)Sea water radiation monitors (Tohoku Electric Power Co., Ltd., possesses two)
(3) Sea water temperature monitoring (Tohoku Electric Power Co., Ltd., possesses seven)
(4) Meteorological facilities in power stations (Tohoku Electric Power Co., Ltd. possesses one)
3. Transmission Interval
Every ten minutes data is sent from the radiation management computer installed in the service building, to the process computers of Onagawa NPP unit 1 and 2. The data at 00:02 was not transmitted, but after the resumption the data is sent as normal.
4. Influence on Safe and Stable Operation of NPPs
Data relating to environmental monitoring was not sent properly to the main control room's process computer at the power station, but this will not affect the safe and stable operations of the NPPs.
The data which was not transmitted was saved as usual on the radiation management computer, installed in the service building.
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