Tokyo Electric Power Co (TEPCO) said Friday it had found an abnormality in one of the valves at a nuclear plant in central Japan used to inject water into reactors in case of an emergency, a news report said.
TEPCO said it did not expect a leakage of radioactive substances from its Kashiwazaki-Kariwa nuclear power plant in Niigata prefecture, Kyodo News reported.
The company said did not expect any impact on the outside environment, DPA reported.
TEPCO said it was examining the cause of the malfunction.
While looking into electrically operated valves in the residual heat removal system at reactor number 1 Thursday, TEPCO found that one of the valves did not close properly, and had to close it manually, Kyodo said.
Other valves were working properly and there was no problem with the plant's overall operations, TEPCO said.
Meanwhile, Japanese State Secretary for Foreign Affairs Yutaka Banno on Thursday sought cooperation from Russia in bringing the quake-damaged Fukushima Daiichi nuclear plant under control.
Banno made the request at a meeting with Russian Vice Foreign Minister Aleksei Borodavkin, since Russia went through the 1986 Chernobyl disaster when it was part of the Soviet Union.
With Russia putting import restrictions on Japanese food following radiation leaks from the plant, Banno also asked Moscow to take a calm stance based on objective data, Jiji Press reported.
Borodavkin indicated that Moscow was ready to cooperate in accordance with the requests, Jiji said.