Tokyo Electric Power Co. has shut down a reactor in Fukushima Prefecture after discovering a radiation leak, company officials said Tuesday.

The company said no unusual levels of radiation were detected in the atmosphere outside the premises of its Fukushima No. 2 nuclear plant, which was shut down Monday night.

The leak follows revelations that Tepco falsified reports and failed to carry out repairs on cracks in reactors, including the one that has been shut down, for more than 10 years. The utility claimed, however, that the leak is not related to the coverups.

The officials said instruments detected radiation of about 130 times the normal level in the steam to drive a turbine at the No. 2 reactor of the plant at 7:44 p.m. Monday. Slightly higher than normal levels of radiation were detected in exhaust from the building, it said.

Prior to the leak, radiation levels were found to have risen at 5:49 p.m. Monday in circulating cooling water at the reactor.

Tepco said it suspects a minute hole in a tube containing nuclear fuel allowed radiation to leak to the coolant water, leading to the high levels of radiation in the steam.

In the scandal that broke last week, Tepco reportedly falsified reports on a crack in the shroud of the 1.1 million kw boiling-water reactor in the Fukushima No. 2 plant, and continued operating it without mending the crack.

The officials said that as the reactor has been shut down, the utility will check the shroud now instead of waiting until late October as earlier planned.