The k2p blog

The path to complete cooling and stability will not be smooth or easy at Fukushima Dai-ichi nuclear plant. New complications and setbacks in Reactors #1,2 and 3 are leading to new strategies and actions. There will no doubt be many more such challenges in the days and weeks ahead.

Update 25th March midnight JST (1600 CET):

TEPCO said Friday it has begun injecting freshwater into the No. 1 and No. 3 reactor cores at the crisis-hit Fukushima Daiichi nuclear plant to enhance cooling efficiency, although highly radioactive water was found leaking possibly from both reactors as well as the No. 2 reactor.

The latest efforts to bring the troubled reactors at the plant under control are aimed at preventing crystallized salt from seawater already injected from forming a crust on the fuel rods and hampering smooth water circulation, thus diminishing the cooling effect, the plant’s operator said.

A day after three workers were exposed to water containing radioactive materials 10,000 times the normal level at the turbine building connected to the No. 3 reactor building, highly radioactive water was also found in the turbine buildings of the No. 1 and No. 2 reactors.

Early Friday, concern grew that the high-level radiation leak detected with the workers’ exposure Thursday could indicate possible damage to the No. 3 reactor vessel, but the government’s nuclear safety agency later denied the possibility, saying no data, such as on the pressure level, have suggested the reactor vessel has cracked or been damaged. The No. 3 reactor used plutonium-uranium mixed oxide fuel for so-called ”pluthermal” power generation.

While the high-level radiation is suspected to have come from the reactor, where overheating fuel rods are believed to have partially melted, it remains uncertain how the leak occurred, said Hidehiko Nishiyama, spokesman for the government’s Nuclear and Industrial Safety Agency.

He said further verification is needed to find out how the radioactive water reached the underground site where the workers were exposed. Huge volumes of water have been poured into the reactor as well as its apparently boiling spent fuel pool since they lost their cooling functions.

In addition to the infusion of freshwater to the No. 1 and No. 3 reactors, it injected seawater to the spent fuel pools of the No. 2 and No. 4 reactors through pipes, and firefighters sprayed a massive amount of seawater onto the No. 3 fuel pool, the utility said.

The government, meanwhile, encouraged residents within 20 to 30 kilometers of the plant to leave voluntarily, citing concerns over access to daily necessities, while maintaining its directives for them to remain indoors and for residents within 20 km of the plant to evacuate.

Tags: fresh water cooling, Fukushima Dai-ichi nuclear plant, TEPCO

This entry was posted on March 25, 2011 at 7:40 pm and is filed under Japan, Natural Disasters, Nuclear Power. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.