29 Avril 2016
April 27, 2016
A panel of scientists has presented to Japan's Nuclear Regulation Authority an assessment that says a fault under a reactor in central Japan could slip sometime in the future.
The conclusion could lead to the scrapping of the reactor although the issue will undergo further scrutiny by the authority's commissioners.
The panel's report, presented on Wednesday, deals with the No.1 reactor at the Shika nuclear plant in Ishikawa Prefecture on the Japan Sea coast.
The report upholds a draft assessment conducted in July last year. The report says it is reasonable to believe the fault below the reactor shifted during or after a geological period called the Late Pleistocene, between 120,000 and 130,000 years ago.
And it concludes that it is undeniable the fault could move in the future.
The plant's operator, Hokuriku Electric Power, has been insisting that the fault is not active and is aiming at restarting the reactor, which is currently offline.
Construction of reactor buildings and other key facilities is not allowed above active faults.
But the panel's report adds that its conclusion was derived from limited data, such as sketches of strata made at the time the plant was built.
It notes that surveys of strata on the southeastern side of the reactor, which is on the extension of the fault beneath the reactor, detected no sign of movement over the past 130,000 years.
It says additional data and further analysis would be necessary to make a more accurate assessment.
The operator plans to apply for screening to resume operations of the No.1 reactor. At that time, the regulators will discuss additional data to be presented by the operator.
The report also notes that other faults running beneath cooling pipes leading to the No.1 and 2 reactors could distort the ground in the future. The operator may be required to relocate or reinforce facilities to address this possibility.