The operator of the damaged Fukushima Daiichi nuclear plant says radioactive water may have leaked from a storage tank whose pivot bolts used for the joints of steel sheets had become loose.
In August, more than 300 tons of highly radioactive water was found leaking from one of the storage tanks. But one month later the cause of the leakage is still unknown.
In order to find the cause of the problem, the plant operator on Tuesday began work to dismantle the tank.
TEPCO officials say 5 of the pivot bolts used to fix joints of steel sheets at the bottom of the tank were found loose. They say it is highly probable that this caused the leakage.