• Sat
  • Dec 27, 2014
  • Updated: 11:10pm

Fukushima nuclear accident

The Fukushima Daiichi nuclear disaster was a series of equipment failures, nuclear meltdowns and releases of radioactive materials at the Fukushima nuclear power plant in northeastern Japan, following a devastating earthquake and tsunami on 11 March 2011 which claimed nearly 19,000 lives. It is the largest nuclear disaster since Chernobyl in 1986 and only the second disaster to measure Level 7 on the International Nuclear Event Scale.

NewsAsia
JAPAN

Tokyo asks Nagasaki bomb maker for help in fighting Fukushima leaks

Officials fighting toxic leaks at Fukushima turn to US firm that produced plutonium dropped on Nagasaki for advice on 'cocooning' safety process

PUBLISHED : Saturday, 17 August, 2013, 12:00am
UPDATED : Saturday, 17 August, 2013, 3:00am

Hanford Engineer Works in the US northwest produced the 9kg of plutonium for the bomb that destroyed Nagasaki in 1945.

Now Japan is turning to the nuclear production and waste facility for help.

Hanford is home to one of the most toxic nuclear waste sites in the world and is providing help dealing with the melted nuclear reactors in Fukushima.

Tokyo Electric Power Co. (Tepco) sent engineers to the Hanford site this year to learn from decades of work treating millions of litres of radioactive waste. Hanford also pioneered a method of sealing off defunct reactors known as concrete cocooning that could reduce the 11 trillion yen (HK$868 billion) estimated cost for cleaning up the Fukushima power station.

The Hanford site stretches over 1,500 square kilometres of scrubland, about 320 kilometres southeast of Seattle. Its laboratories and plutonium facilities were integral to the Manhattan Project to make the first atomic bomb, and it went on to produce most of the plutonium in the US nuclear arsenal. But the last of its nine reactors was shut down in 1987 in a decommissioning process that has continued to occupy thousands of technicians.

Masumi Ishikawa, general manager of Tepco's radioactive waste management division, said: "The US has vast experience in nuclear technology with their military activity, including decontaminating soil and managing river contamination. There's a lot we can learn from them."

Prime Minister Shinzo Abe confirmed last week that the country was seeking outside help in dealing with the Fukushima-Daiichi plant, from which about 300 tonnes of irradiated water is leaking into the sea each day.

He promised more government funds for the clean-up.

But Hanford has its own share of containment challenges. Six underground tanks there continue to leak radioactive waste, and efforts to contain them may offer lessons to Tepco. The tanks are among 177 buried at Hanford along the Columbia River.

The US Department of Energy has spent more than US$16 billion since 1989 to clean up Hanford, which generated 211 million litres of radioactive waste during its time supplying the US nuclear arsenal.

Tepco's Ishikawa - one of the so-called "Fukushima 50" who risked their lives to prevent a full meltdown at the plant - said he and other Tepco engineers had visited Hanford to evaluate its containment technology.

The last of Hanford's nine reactor's was "cocooned" in June last year, with the reactor building first being demolished down to the reactor's core, which was already surrounded by a 1.2 metre concrete shield.

The core was then wrapped in more concrete to provide safe storage for 75 years, allowing radiation levels to decay gradually before a final method of disposal is decided on.

There are two other ways to decommission nuclear reactors, said Ishikawa - immediate dismantling, or entombing the whole building in concrete, which was used at the wrecked Chernobyl plant in Ukraine.

Entombing and cocooning cost less than immediate dismantling as they reduce the cost of handling and moving highly radiated material, Ishikawa said.

Tepco is talking with the US Department of Energy on whether Hanford-style cocooning could work at Fukushima.

Sealing the reactors for 75 years would allow more time to focus on cleaning up surrounding areas so that residents could return, said Ishikawa.

Around 160,000 people were forced to flee when the Dai-Ichi plant released clouds of radiation after it was hit by an earthquake and tsunami on March 11, 2011.

"Decommissioning is vital for the areas around Fukushima Dai-Ichi to move ahead with restoration," Ishikawa said.

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