More highly radioactive water at damaged Japanese nuclear plant

The operator of a damaged Japanese nuclear power station said highly radioactive water was inundating the basement of one of one of the reactor buildings at the Fukushima Daiichi nuclear plant, a news report said Tuesday.

Tokyo Electric Power Co (TEPCO) detected levels of 2 million becquerels of radioactive caesium per cubic centimetre of water in the basement of reactor 1. TEPCO suspects that radioactive materials from the melted fuel have leaked from the reactor's pressure vessel, DPA reported.

The large amounts of contaminated water have prevented TEPCO workers for restoring key cooling functions. Concerns are now rising as the increase in water accumulation coincides with the onset of the rainy season.

Since the plant was crippled by the March 11 earthquake and tsunami, it has leaked radioactive materials into the environment.

Rain showers that had started in the region Sunday caused the water levels in the turbine buildings of rectors 2 and 3 to rise at a faster pace of 3 to 4 millimeters per hour, public broadcaster NHK reported.

TEPCO said in mid-May the company would aim to create a water circulation system in which it would remove radioactive substances from the water flooding the reactor buildings and use it to cool the reactors. The new system is expected to be ready in July.

As other measures are needed to stop further leakage until then, the company plans to transfer the water to a new wastewater facility site.

On Monday, rating agency Standard & Poor's downgraded its long-term credit rating for TEPCO to junk status, down five notches to B+ from BBB.

TEPCO, which posted a loss of 1.25 trillion yen (15.3 billion dollars) in the year ended March 31, has problems to to come up with funds to cover compensation payments for the nuclear disaster.

Short-term corporate rating was cut to B from A-2 and long-term bond ratings reduced to BB+ from BBB.

"TEPCO's worsening financial position increases the likelihood its lender banks could restructure its borrowings," the rating agency said.