TEPCO investigates cause of radiation spike

February 23, 2015

TEPCO trying to identify cause of high radiation

http://www3.nhk.or.jp/nhkworld/english/news/nuclear.html

Feb. 23, 2015 - Updated 14:14 UTC+1

The operator of the Fukushima Daiichi nuclear plant says it has yet to identify the cause of a rise in radioactivity in a drainage channel.

Tokyo Electric Power Company detected high levels of beta-ray-emitting substances in the channel on Sunday morning.

Measurements showed that levels of the substances had risen as high as 7,230 becquerels per liter -- 10 times the usual level.

The utility suspects that contaminated water in the channel may have leaked into the port.

TEPCO officials say their investigations have so far found no leaks in the tubes and tanks storing radioactive water on the premises. They also say the levels of the radioactive substances went down to 20 becquerels per liter on Sunday night.

The drainage channel is designed to discharge rainwater, as well as water used in various operations, into the port.

TEPCO officials say workers removed accumulated mud from the channel on Saturday, the day before the event. But they say they do not know whether the removal is related to the rise in radiation levels.

The company says there has been no leakage of the substances outside the port and that radiation levels of the water in the port are within the normal range.

Toxic water at Fukushima plant leaked into nearby bay

http://mainichi.jp/english/english/newsselect/news/20150223p2g00m0dm041000c.html

TOKYO (Kyodo) -- Highly radioactive water at the crippled Fukushima Daiichi nuclear plant has leaked into a nearby bay, but the cause and amount of the leakage have yet to be investigated, Tokyo Electric Power Co. said Monday.

A company official said the bay is surrounded by fences and the plant operator believes the water did not flow into the ocean outside the bay, but details remain unknown.

According to TEPCO, radiation levels more than 70 times greater than usual were detected in a gutter on the premises of the complex on Sunday. The levels of beta ray-emitting substances, such as strontium, measured up to 7,230 becquerels per liter as of Sunday morning, but fell to 20 becquerels by around 10 p.m. the same day.

TEPCO had shut the gutter, which drains rain water into the bay, but the firm opened the gate on Monday after confirming that radiation levels have lowered.

The problem of radioactive water building up at the Fukushima site remains a major challenge in the process of decommissioning nearly four years after the outbreak of the nuclear crisis. In December, TEPCO said around 6 tons of radioactive water leaked into the ground, in a series of recent mishaps at the plant.

February 23, 2015(Mainichi Japan)