More Fukushima related news – for California

LOS ANGELES (Jiji Press) — A U.S. institute has said that trace amounts of radioactive cesium-134 emitted from Tokyo Electric Power Co.’s Fukushima No. 1 nuclear power plant were detected in Pacific waters off the northern California coast.

The radioactive substance was found in water collected at a point about 150 kilometers off Eureka, Calif., in August this year, according to the Woods Hole Oceanographic Institution.

It is the first time that a radioactive material from the crippled plant has been detected in waters off the United States.


Meanwhile in Fukushima

Tokyo Electric Power Co. will postpone scrapping the crippled No. 1 unit of its Fukushima No. 1 nuclear power plant as the company has already run into delays, officials said.

TEPCO presented draft revisions to its plan at a meeting with the government on Thursday. The two sides are working to revise the existing reactor dismantling timetable by next spring.

The draft calls for deferring the start of operations to remove spent nuclear fuel stored in a fuel pool in the No. 1 unit until fiscal 2019. It is currently scheduled for fiscal 2017.

It also calls for the removal of melted nuclear fuel to begin in fiscal 2025, against the current target of fiscal 2020.

“We haven’t decided on the new timetable yet,” said an official at the Agency for Natural Resources and Energy. “We are seeking to move forward with the schedule as much as possible.”

But radiation levels remain elevated in the disaster-hit nuclear plant, making it hard to speed up the work.

Radioactive water issue cannot be resolved by ice wall project alone

From today’s Yomiuri Shimbun

Tokyo Electric Power Co. has launched the construction of ice walls, a project aimed at curbing the buildup of radioactive water at its crippled Fukushima No. 1 nuclear power plant.

Halting the increase of contaminated water is the major task for the moment to end the crisis at the plant. Therefore, the project must be steadily promoted.

Pipes to circulate liquid coolants will be buried over a 1.5-kilometer perimeter around the plant’s Nos. 1 to 4 reactor buildings, thereby freezing the soil to a depth of 30 meters below ground to construct ice walls. The government and TEPCO expect the envisaged ice walls to help prevent groundwater from flowing into the reactor buildings, which has caused an increase of contaminated water at the plant.

Many essential pipes and electrical cables are installed underground around the reactor buildings. If such equipment is accidentally damaged, it could impair the cooling functions of the reactors.

Given the high radiation levels at the construction site, it is necessary to minimize workers’ radiation exposure. Due care must be taken in carrying out the work.

Installation will cost ¥32 billion. The government will bear the cost as a research and development project. Power consumption equivalent to that of 13,000 ordinary households, running more than ¥1 billion annually in simple calculation, will be needed to keep the underground walls frozen.

Such massive spending aside, the question is whether the ice walls will ensure that groundwater will not flow into the reactor buildings.

Ice walls have been used as a temporary method of halting the flow of groundwater when tunnels are constructed. The installation of ice walls on the currently planned scale is unprecedented in Japan.

Fears of subsidence

There are fears that if the soil is not frozen evenly, it could cause subsidence. Experts have warned that if the ice walls melt due to problems with cooling functions, there could be a widespread danger of radioactive water flowing outside the reactor buildings.

There is no reason to place overly high expectations on the ice walls.

Considering the fact that there has been constant trouble with the countermeasures taken so far to deal with radioactive water, it is essential to carry out several measures in parallel.

The amount of contaminated water has increased by 300-400 tons a day. Storage tanks built on the plant’s premises already number about 900, leaving no choice but to assign many workers to maintenance and surveillance duties.

This hinders work to repair the crippled reactors, which must be given top priority to end the crisis at the plant. This must be taken seriously.

Sooner or later, there will be no more sites available for the construction of storage tanks at the plant.

It is vital to reduce the amount of rainwater infiltrating the soil as one of the countermeasures. The decision was made to pave the plant’s site, but little progress has been made due to a delay in land leveling.

New highly radioactive leak at Japan’s Fukushima plant

TOKYO (Reuters) – The operator of Japan’s Fukushima nuclear plant said on Thursday that 100 tonnes of highly contaminated water had leaked out of a tank, the worst incident since last August, when a series of radioactive water leaks sparked international alarm.

Initial measurements of the latest incident showed the leaked water had a reading of 230 million becquerels per litre of beta-emitting radioactive isotopes, including strontium 90.

The legal limit for releasing strontium 90 into the ocean is 30 becquerels per litre.

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