Shika (Japan)

Map of Shika

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Two units in operation since 1993 and 2006

Facilities in Shika

plantreactor typconstruction startoperation startshut down
Shika-1BWR19881993
Shika-2ABWR20012005
2009-03-30

The Shika 1 reactor has restarted for tests after a prolonged shutdown following a safety revelation.

Hokuriku Electric Power Company announced today the start of a two-week program of checks, starting with pressure tests of the reactor and its coolant circuits. The reactor has already started and Hokuriku said it would gradually build up pressure in main systems to normal operating levels in order to confirm the performance of steam generators, piping and valves.

This trial operation at less than the unit's full power of 505 MWe would then be accompanied by a test of turbine generator systems which would produce some power. After this the unit is planned to be shut down for 'hot' tests of new systems added recently to increase seismic safety.

The resumption of commercial operation and power generation at maximum levels is planned for mid April.

Shika 1 was ordered to shut down as part of a drive from the Japanese Ministry of Economy, Trade and Industry (Meti) to improve the level of safety in all electricity generating companies. During a Meti-ordered purge of records, Hokuriku admitted that a criticality incident had occurred in June 1999 during a periodic inspection.
(source: world nuclear news)

2007-04-23

"On 15 March 2007, the Nuclear and Industrial Safety Agency (NISA) received a report from Hokuriku Electric Power Company (HEPCO) on a criticality accident at Shika Nuclear Power Plant unit 1 (BWR). The accident occurred on 18 June 1999 during a periodic inspection, but was not reported to NISA.

Hokuriku admitted a past safety lapse to the Japanese Ministry of Economy, Trade and Industry as part of a purge of records intended to help transform corporate safety culture in all electric operating companies, nuclear and otherwise.

The lapse in question was a criticality event that occurred at Shika 1 while it was shut down for a planned inspection on 18 June 1999.

The event occurred because of mismanagement of the routine testing of the hydraulic control rod system, which caused a pressure increase in the control rod withdrawal pipes. This resulted in the unwanted drop of three control rods, which lead to a local criticality event. The chain reaction was terminated by operators’ intervention 15 minutes later."

The report of the accident was submitted from HEPCO to NISA on March 30 and April 6, 2007.
(source: http://www.world-nuclear-news.org/nerliste.aspx?id=11762)

2006-01-26

"During start up for trial operations, one valve failed to close fully when testing opening and closing of the steam supply isolation valves in the reactor core isolation cooling system. The reactor was shut down manually. "
(source: http://cnic.jp/english/)

2002-04-02

"Reactor Shika-1 manually shut down due to recirculation pump shaft oscillation during test operation."
(source: http://cnic.jp/english/)

1999-06-18

An uncontrolled criticality incident happend at Hokuriku Electric's Shika-1 (BWR, 540 MW) on June 18, 1999. "Preparations were being made to test the reactor's shutdown function. All control rods were supposed to have been fully inserted at the time, but three rods dropped out of position. Hokuriku Electric presumes that
an incorrect valve adjustment caused the rods to drop. The reactor went critical and remained in that state for fifteen minutes. The manager of the Shika plant decided not to report the incident to the government and records of the incident were not kept. "
source: nuclear monitor no 654

1997-12-15

Hakui City of Ishikawa Prefecture began distributing iodine tablets to day-care centers, kindergartens, and elementary and junior high schools at the end of December, as a preparatory measure against the possible release of radioactivity during an accident at Shika Nuclear Power Plant (BWR, 540 MW). The reactor is located about 19 km away from the city.
In Japan, areas designated as most dangerous during a nuclear accident are those located within 10 km from reactors. Hakui City is outside the designated area, but since 1992 it has autonomously stockpiled iodine tablets in hospitals. The recent measure to distribute tablets to schools was enacted in response to citizen concern that stockpiling the tablets at hospitals may delay distribution to children at the time of an emergency.

1994-08-26

A japanese court turned down a request to close the plant on safety grounds. Less than a day after the verdict in the morning of the 26 as the unit was running at full power, one of the two RCP tripped. Power was reduced to 200 MW. The local government demanded a shutdown when it was informed about the incident. The plant was manually scrammed on Aug 27. Cause was probably problems with speed regulation.