The operator of a damaged Japanese nuclear plant suspended another test run of a newly installed water-treatment system after its pump stopped on Tuesday.
Tokyo Electric Power Co said the pump was overburdened by excessive liquid flow, Kyodo News reported.
The system designed to decontaminate highly radioactive water stopped only five hours into full operation on Friday at the Fukushima Daiichi plant, 250 kilometres north-east of Tokyo.
The operator concluded on Monday that absorbent materials inside the decontamination equipment needed changing more frequently than previously estimated, public broadcaster NHK reported.
The company is trying to reduce radioactivity in water that has accumulated around the plant as a result of emergency measures to cool the reactor cores. Storage facilities for contaminated water were reaching capacity.
Several of the plant’s six reactors have been overheating and leaking radioactive material since it was damaged in the March 11 earthquake and tsunami.
The operator also said Monday night that a plant worker was found to have been exposed to radiation above the official limit, bringing the number of over-exposed workers to nine, Kyodo reported.
The operator has been checking the external and internal radiation exposure of a total of more than 3,500 workers engaged in the emergency work, Kyodo said.
