TOKYO (AP) – The operator of the devastated Fukushima nuclear power plant said on Monday that two seismometers in one of the three molten reactors have been out of service since last year and have collected no data when a powerful earthquake hit the area earlier this month.
The recognition raised new questions about whether the company’s risk management has improved since a massive earthquake and tsunami in 2011 destroyed much of the plant.
The faulty seismometers surfaced at a meeting of the Nuclear Regulation Authority on Monday to discuss new damage to the plant from a magnitude 7.3 earthquake that hit the region on Feb. 13. Cooling water and pressure levels dropped in Units 1 and 3 reactors, indicating additional damage to their primary containment chambers.
The operator, Tokyo Electric Power Co., has been repeatedly criticized for hiding problems and delayed disclosure of problems at the plant.
Regulatory officials asked TEPCO at the meeting why it had no seismological data from the Unit 3 reactor for Saturday’s earthquake, and utilities acknowledged that both seismometers had failed – one in July and the other in October – and never repaired.
TEPCO also said that seismometers, all but two of the reactor buildings that survived the 2011 disaster, were underwater from the tsunami and have never been replaced.
At Monday’s meeting, regulatory officials said they were concerned about declining water levels and pressures in the primary containment chambers of units 1 and 3 due to the possibility that the earthquake had increased existing damage or opened new leak paths, and urged it utility company to check for any elevated radiation levels in the groundwater around the reactor buildings.
TEPCO said no abnormality has been detected in water samples so far.
New damage could further complicate the plant’s already difficult decommissioning process and add to the large amounts of contaminated water stored at the plant.
Since the 2011 disaster, cooling water has been constantly escaping from the damaged primary containment vessels to the basements of reactor and turbine buildings, where its volume increases with the ingress of groundwater. The water is pumped up and treated, after which part of it is reused as cooling water, while the rest is stored in about 1,000 tanks.
TEPCO initially reported that there was no anomaly at the plant after Saturday’s earthquake. But on Monday it said that about 20 of the tanks had shifted slightly as a result of the earthquake, a storage container of radioactive waste had toppled, and the asphalt pavement at the plant had cracked.