2 Août 2013
August 1, 2013
The operator of the Tsuruga nuclear power plant in Fukui Prefecture insists that spent nuclear fuel in the storage pool of the No. 2 reactor will not melt down even if the pool cooling water is lost due to an accident.
That possibility is much in the minds of nuclear experts these days because of fears the plant is situated on an active earthquake fault.
Japan Atomic Power Co. was responding to a request from the Nuclear Regulation Authority to study the safety of nuclear fuel stored in the pool in the event of an earthquake caused by the fault.
The NRA, the government’s nuclear industry watchdog, contends the plant would be a ticking time bomb if it goes back online. But Japan Atomic Power, which released its report July 31, has disputed the finding.
The NRA in May concluded that an active fault runs directly underneath the No. 2 reactor building. Japan Atomic Power was forced to evaluate what risks that might pose to spent fuel stored in a pool if an accident occurred.
Currently, no fuel is stored in the No. 2 reactor, which has been offline since May 2011. However, around 1,700 fuel assemblies, each comprising a number of fuel rods, have been stored in the pool in the building.
According to Japan Atomic Power, even if the cooling water is lost, there is no likelihood of a fuel meltdown. It said that scenario is avoidable because air flowing between the fuel assemblies would serve as a cooling agent. However, it acknowledged that the temperature of the metal pipes that cover the fuel would rise to 420 degrees.
It reasoned that no new measures are warranted.
Japan Atomic Power did not address a scenario in which the fuel assemblies could be displaced due to shaking from an earthquake.
That leaves the door open for the NRA to order Japan Atomic Power to make an entirely new evaluation.
On July 16, Japan Atomic Power took issue with the NRA on its judgment regarding the active fault and formally expressed its opposition to the finding.
The latest report was submitted to avoid being slapped with punitive steps for not following the NRA’s instructions.