Sharp spike in radioactivity in Fukushima after fresh leaks

TEPCO, the company that was recently praised by IAEA for its efforts, faces an uphill task of managing radioactive waste inthe 2011 disaster-hit nuclear power plant

By Anupam Chakravartty
Published: Wednesday 25 February 2015


Tokyo Electric Power Company (TEPCO) officials have said that sensors placed in Daiichi Nuclear Power Plant in Japan’s Fukushima detected a fresh leak of radioactive water into the sea. This is the same plant which was hit by a nuclear disaster, triggered by a tsunami in 2011.

The contamination levels in the present leak are 70 times greater than the levels recorded in the already-contaminated area close to the power plant. Nearly a week before, the International Atomic Energy Agency (IAEA) had said that Japan has made significant progress in containing the leakages.

International advisers to Japan’s regulator Nuclear Regulation Authority, however, are worried that a mandatory review of its performance could lead to a loss of independence for the body, created in the wake of the 2011 Fukushima nuclear disaster.

On Sunday, at about 10:00 am, local time, the sensors connected to drainage systems detected contamination levels of beta ray-emitting substances, such as strontium-90, measuring 5,050 to 7,230 Becquerels per litre of water. According to the norms, the discharge to the sea should remain below five Becquerels. At its peak the radioactivity was 70 times more than the accepted norms. Later on Sunday, the contamination levels, however, decreased to about 10 to 20 times. According to a release by TEPCO, inspection of storage tanks, reserved for radioactivesubstances, did not show any leaks. However, the drain has been blocked by the authorities, thus stopping the discharge to the sea. Tepco officials are yet to find out the exact cause of this spike in radioactivity levels in the discharge.

Tepco’s troubles nowhere near end

Tepco, however, has been facing difficulty in controlling large amounts of groundwater flowing from the mountainous area towards the nuclear power plant in the middle of the subterranean flow. It has been estimated that everyday, about 400,000 litres of water flow from the higher reaches of the mountain and enter the sub soil below the nuclear power plant. With no access to three reactors that are experiencing a meltdown, TEPCO has been pumping large amounts of water to cool the reactors. The contaminated water is drained out and stored in over 1000 tanks. However, rain water and ground water often gets mixed at the lower levels, leading to contamination.

Since June last year, TEPCO has been looking at several solutions to decontaminate the plant area and decommission the nuclear power plant. TEPCO authorities have been trying to freeze the sub-soil to curb the flow of groundwater to the power plant and divert the flow. The frozen shields are intended to block groundwater from the nearby mountains from flowing into the reactor building basements. TEPCO claims it can decontaminate the water by using its advanced liquid processing system (ALPS). However, recent news reports showthat ALPS system is not coping well. So far, three ALPs have been used. With this latest leak, the authorities are going to miss the fresh deadline of May 2015 to start the construction of the shields and cleanup using ALPs.

Autonomy at risk

On February 17, a 15-member IAEA expert team completed a third review of Japan's efforts to plan and implement the decommissioning of nuclear power plant. The international peer review of Daiichi Nuclear Power Station Units 1 to 4 started on February 9. According to the team leader, Juan Carlos Lentijo, IAEA Director of Nuclear Fuel Cycle and Waste TechnologyJapan made significant progress since IAEA’s previous missions. “The situation on the site has improved and progressive clean-up has led to reduced radiation dose levels in many parts of the site,” said Lenjito. In a release on the completion of the visit, the team noted that TEPCO successfully removed the spent fuel from nuclear reactor four, which did not suffer much damage during the 2011 tsunami and earthquake. However, Lenjito also said the situation at the site remains very complex with the increasing amount of contaminated water posing a short-term challenge that must be resolved in a sustainable manner. “The need to remove highly radioactive spent fuel, including damaged fuel and fuel debris, from the reactors that suffered meltdowns poses a huge long-term challenge,” said the IAEA expert. According to Tepco officials, proper remediation of the site will take at least 40 years.
On the other hand, international advisers to the Japan’s Nuclear Regulation Authority, which came into existence after the tsunami caused extensive damage to the Daiichi plant in Fukushima, are worried that a mandatory review of its performance could lead to a loss of independence for the body. While welcoming a review of the NRA, the advisers, which include the chairman of the International Atomic Energy Agency’s International Nuclear Safety Group, Richard Meserve expressed his concerns over political interference in a document sent to the Japan’s cabinet earlier in February. “We are concerned about any transfer of authority that would serve to compromise the regulator’s independence,” the document says.“Indeed, given the problems associated with the previous regulatory structure, we suspect the maintenance of a clearly independent regulator is likely to be essential to the restoration of public confidence in nuclear power.”

The review of NRA operations started in September 2014, but no decisions have been made on whether the cabinet office will assume oversight, reports local English daily, Japan Times. On top of that, Japanese Prime Minister, Shinzo Abe remains a proponent of nuclear energy seeking the start of the nuclear power plants in the country, which remains shut since the tsunami hit Japan in 2011.

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