A reactor at
The No. 4 reactor was halted at
Abnormalities were picked up by at least two of the four neutron detectors installed outside the reactor vessel, according to the operator.
It was the first automatic shutdown of a reactor since the No. 3 unit at the same plant was halted in 1988 due to a similar warning,
The Fukui prefectural government said the incident could have been caused by a problem with the neutron detectors or a falling control rod. Control rods inside the reactor are used to control nuclear chain reactions by absorbing neutrons.
No abnormality was detected when
The No. 4 reactor was reactivated on
The seaside plant has four reactors and faces the Sea of
==Kyodo
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