Tsuruga Nuclear Plant May Have Been Sitting On Top Of An Active Fault For All These Years

Tsuruga Nuke Plant Reactor 2 May Have Been Sitting on Top of Active Fault All These Years (EX- SKF, April 24, 2012):

As the mayor of Tsuruga City was strongly promoting nuclear power generation in the county in China that has a nuclear power plant with 6 operating reactors and 4 under construction, the Nuclear and Industrial Safety Agency warned the operator of Tsuruga Nuclear Power Plant that Reactor 2 of the plant may be sitting on an active fault.

Even in Japan, the national guideline is not expecting a reactor to be built on top of an active fault.

Reactor 2 of Tsuruga Nuclear Power Plant is a pressurized water reactor made by Mitsubishi Heavy Industries. Reactor 1 is a light water reactor by GE. Tsuruga’s Reactor 2 was considered to be one of the better made PWRs in Japan. Both reactors have been shut down for regular maintenance.

Construction of Reactor 2 started in 1982, and the reactor started operation in 1987.

Two more reactors are being built at Tsuruga Nuke Plant. The reactors will be Advanced Pressurized Water Reactors (APWR) by Mitsubishi Heavy Industries. If they proceed with the construction, that is.

From NHK News (4/25/2012):


“An active fault” at Tsuruga Nuclear Power Plant to be studied again


An expert has pointed out the possibility that cracks that run under Tsuruga Nuclear Power Plant in Fukui Prefecture are active faults. The Japan Atomic Power Company (JAPC) is going to do the survey again and come up with the plan.


On April 24, an expert in active faults and officials from the Nuclear and Industrial Safety Agency (NISA) studied the area where the strata are exposed at JAPC’s Tsuruga Nuclear Power Plant in Tsuruga City in Fukui Prefecture. They particularly looked at the crack called “fracture zone”.


As the result, the expert pointed out that the crack that runs underground at about 150 meters west of Reactor 2 “may be an active fault, and it may move together with the active fault called Urazoko Fault that runs through the compound, making the shaking from an earthquake bigger than anticipated”.


There is another crack that runs right beneath Reactor 2. It needs to be studied to determine if it is also an active fault. NISA has instructed JAPC to do the survey again.


The guideline for seismic design by the national government does not expect having an important facility of a nuclear power plant right above an active fault. If the crack beneath Reactor 2 turns out to be an active fault, there is a possibility that JAPC cannot restart the reactor.


JAPC will report to NISA shortly with the plan for the survey, and will study the strata to decide what to do.


JAPC says, “The result of the survey may affect various issues such as expected maximum earthquake and seismic stability of the plant. We would like to proceed very cautiously.”

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