Scientists call for radiation exposure reduction

A group of scientists at Fukushima University is urging the prefectural government to take stronger precautions in reducing radiation exposure to citizens.

The group comprises 12 associate professors at the university, including Hazuki Ishida, an environmental engineering specialist. On Monday they presented the Fukushima Governor with a 7-point request in connection with the accident at the Fukushima Daiichi nuclear power plant. A health risk management expert for the prefecture said that radiation exposure of up to 10 microsieverts per hour causes no health problems.

But for those remaining outdoors in such conditions for only 5 days, the total radiation exposure will exceed 1 millisievert, the annual limit for ordinary people, as recommended by the International Commission on Radiological Protection.
The professors called for reducing exposure to radioactivity as much as possible and urged the prefecture to establish guidelines toward this purpose.

They also asked that prefectural government radiation experts who say that even relatively low levels of radioactivity are harmful be included as health risk management advisors. They also requested that the prefectural government draw up and make public a concrete plan to remove contaminated topsoil. Ishida says the prefectural government should take measures to protect its residents, on the premise that even low levels of radiation exposure are dangerous.

Monday, June 06, 2011 22:31 +0900 (JST)

http://www3.nhk.or.jp/daily/english/06_35.html



No.1 reactor vessel damaged 5 hours after quake

Japan's nuclear regulator says the meltdown at one of the Fukushima reactors came about 5 hours after the March 11th earthquake, 10 hours earlier than initially estimated by the plant's operator.

The government's Nuclear and Industrial Safety Agency on Monday issued the results of its analysis of data given to it by Tokyo Electric Power Company.

The report says the fuel rods in the Number 1 reactor began to be exposed 2 hours after the earthquake due to the loss of the reactor's cooling system in the tsunami. Its fuel rods may have melted down 3 hours later, causing the damage to the reactor. This means the meltdown occurred about 10 hours earlier than TEPCO estimated last month.

The nuclear agency also says a meltdown damaged the Number 2 reactor about 80 hours after the quake, and the Number 3 reactor 79 hours after the quake. The agency's analysis shows that the Number 2 reactor damage came 29 hours earlier than the TEPCO estimate, and the Number 3 reactor damage came 13 hours later than in the utility's assessment...

http://www3.nhk.or.jp/daily/english/06_33.html



Govt. document shows offsite center dysfunctional

An internal document from Japan's nuclear safety agency reveals that an emergency response office was nearly dysfunctional at the time of the nuclear accident at the Fukushima Daiichi power plant on March 11th.

NHK has obtained a document from the Nuclear and Industrial Safety Agency that shows how the office, called an "off-site center" failed to function properly due to a rise in radiation levels in the wake of a power outage.

Off-site centers were established at 22 locations near nuclear power plants throughout the country after a criticality accident in 1999 at a nuclear fuel processing plant in Tokai Village in Ibaraki Prefecture...

...It reveals that after the power outage, an emergency diesel generator did not work at all, communications were down, and other critical functions were lost...

Monday, June 06, 2011 22:00 +0900 (JST)

http://www3.nhk.or.jp/daily/english/06_34.html


Probe poised to take Tepco to task
Utility tardy in venting reactor pressure, lacked plan for multiple crises, ignored historical data

By REIJI YOSHIDA
Staff writer

Shortly after 7 a.m. on March 12, Prime Minister Naoto Kan confronted Masao Yoshida, director of the Fukushima No. 1 nuclear plant, at the compound in Okuma, Fukushima Prefecture.

Kan flew from Tokyo by chopper to the crippled nuclear plant, desperately wanting to ask one critical question: Why can't Tokyo Electric Power Co. still open valves to release rising steam inside reactor No. 1 to avoid a looming meltdown?

The March 11 megaquake and monster tsunami had already knocked out all the power supply and critical cooling systems of the plant, pushing temperatures and pressure inside reactor 1 to an acutely dangerous level.

Tepco had been unable to open the electric valves because the station had suffered a total blackout. Radiation in the reactor building had already risen to dangerous levels, making Tepco hesitant to send in workers to manually open the valves...

http://search.japantimes.co.jp/cgi-bin/nn20110606x3.html


Experts fear tsunami sludge could lead to infectious disease outbreak

With the rainy season and scorching summer approaching disaster-hit northeastern Japan, experts fear sludge left by the tsunami could cause an outbreak of infectious diseases among local residents.

Sludge brought by the tsunami covered coastal cities in northeastern Japan, but the governments of Iwate, Miyagi and Fukushima prefectures -- the three regions most severely damaged by the disaster -- have yet to find a way to dispose of the considerable amount of sludge covering vast areas.

In the coastal city of Soma, Fukushima Prefecture, dust from dried sludge drifts in the air and restricts visibility.
"The smell of sludge has become stronger than immediately after the earthquake. I must always wear a face mask," said a 57-year-old local man who was cleaning his flooded home in early June.

The rice fields around his house were covered with a black sediment, producing a large number of fly-like insects...

(Mainichi Japan) June 6, 2011

http://mdn.mainichi.jp/mdnnews/news/20110606p2a00m0na006000c.html