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09 July 2012

Reactor stabilization and cleanup operations


Reactor stabilization and cleanup operations

The multiple nuclear reactor units involved in the Fukushima Daiichi nuclear disaster were close to one another and this proximity triggered the parallel, chain-reaction accidents that led to hydrogen explosions blowing the roofs off reactor buildings and water draining from open-air spent fuel pools. This situation was potentially more dangerous than the loss of reactor cooling itself. Because of the proximity of the reactors, plant workers were put in the position of trying to cope simultaneously with core meltdowns at three reactors and exposed fuel pools at three units.
On 21 December 2011, the Japanese government released a roadmap for the cleanup activities, which predicted that the full cleanup will take 40 years.[414] On 10 April 2011, Tokyo Electric Power Company (TEPCO) began using remote-controlled, unmanned heavy equipment to remove debris from around nuclear reactors 1–4. TEPCO announced on 17 April that it expected to have the automated cooling systems restored in the damaged reactors in about three months and have the reactors put into cold shutdown status in six months. TEPCO planned to largely empty the basements of the turbine and reactor buildings of units 1–3 of contaminated water by the end of 2011 to allow workers access to the crucial basement areas of both the turbine and reactor buildings.[415]
When the monsoon season began in June 2011, a light fabric cover was used to protect the damaged reactor buildings from storms and heavy rainfall. On 1 August 2011, TEPCO said that very high radiation levels were found outside the building of reactor 1 and 2 from an exhaust-pipe. On 16 August, TEPCO announced the installation of devices in the spent fuel pools of reactor 2, 3 and 4, which used special membranes and electricity to desalinate the water. These pools were cooled with seawater for some time, and TEPCO feared the salt would corrode stainless steel pipes and the pool walls. Burying the reactors in sand and concrete is considered to be a last resort.
In October 2011, Japanese Prime Minister Yoshihiko Noda said the government will spend at least 1 trillion yen ($13 billion) to clean up vast areas contaminated by radiation from the Fukuahima nuclear disaster. Japan "faces the prospect of removing and disposing 29 million cubic meters of soil from a sprawling area in Fukushima, located 240 kilometers (150 miles) northeast of Tokyo, and four nearby prefectures".[416]

[edit]Energy policy implications

Anti-nuclear power plant rally on 19 September 2011 at the Meiji Shrine complex in Tokyo.
By March 2012, one year after the disaster, all but two of Japan's nuclear reactors had been shut down; some were damaged by the quake and tsunami. Authority to restart the others after scheduled maintenance throughout the year was given to local governments, and in all cases local opposition prevented restarting. The loss of 30% of the country's generating capacity has led to much greater reliance on liquified natural gas and coal.[417] Unusual conservation measures have also been necessary. In the immediate aftermath, nine prefectures served by TEPCO suffered power rationing.[418] The government asked major companies to reduce power consumption by 15%, and some shifted their weekends to weekdays to even out power demand.[419]
According to The Japan Times, the Fukushima nuclear disaster changed the national debate over energy policy almost overnight. "By shattering the government's long-pitched safety myth about nuclear power, the crisis dramatically raised public awareness about energy use and sparked strong anti-nuclear sentiment". A June 2011 Asahi Shimbun poll of 1,980 respondents found that 74% answered "yes" to whether Japan should gradually decommission all 54 reactors and become nuclear free.[420]
An energy white paper, approved by the Japanese Cabinet in October 2011, says "public confidence in safety of nuclear power was greatly damaged" by the Fukushima disaster, and calls for a reduction in the nation's reliance on nuclear power. It also omits a section on nuclear power expansion that was in last year's policy review.[421]
Environmental activists at a 2011 United Nations meeting in Bangkok used the Fukushima disaster as an example to promote accelerated use of renewable energy.[422]
Physicist Amory Lovins has said: "Japan is poor in fuels, but is the richest of all major industrial countries in renewable energy that can meet the entire long-term energy needs of an energy-efficient Japan, at lower cost and risk than current plans. Japanese industry can do it faster than anyone — if Japanese policymakers acknowledge and allow it".[293]Benjamin K. Sovacool has said that, with the benefit of hindsight, the Fukushima disaster was entirely avoidable in that Japan could have chosen to exploit the country's extensiverenewable energy base. Japan has a total of "324 GW of achievable potential in the form of onshore and offshore wind turbines (222 GW), geothermal power plants (70  GW), additional hydroelectric capacity (26.5 GW), solar energy (4.8 GW) and agricultural residue (1.1 GW)."[423]
One result of the Fukushima Daiichi nuclear disaster could be renewed public support for the commercialization of renewable energy technologies.[424] In August 2011, the Japanese Government passed a bill to subsidize electricity from renewable energy sources. The legislation will become effective on 1 July 2012, and require utilities to buy electricity generated by renewable sources including solar powerwind power and geothermal energy at above-market rates.[425]
In September 2011, Mycle Schneider said that the Fukushima disaster can be understood as a unique chance "to get it right" on energy policy. "Germany – with its nuclear phase-out decision based on a highly successful renewable energy program – and Japan – having suffered a painful shock but possessing unique technical capacities and societal discipline – can be at the forefront of an authentic paradigm shift toward a truly sustainable, low-carbon and nuclear-free energy policy".[426]
As of September 2011, Japan plans to build a pilot floating wind farm, with six 2-megawatt turbines, off the Fukushima coast.[427] After the evaluation phase is complete in 2016, "Japan plans to build as many as 80 floating wind turbines off Fukushima by 2020."[427]
In 2012, Naoto Kan said the Fukushima disaster made it clear to him that "Japan needs to dramatically reduce its dependence on nuclear power, which supplied 30% of its electricity before the crisis, and has turned him into a believer of renewable energy".[291]
Sales of solar cells in Japan rose 30.7% to 1,296 megawatts in 2011, helped by a government scheme to promote renewable energy. Canadian Solar plans to build a factory in Japan and is currently in negotiations with local governments in Fukushima and Miyagi prefectures. The facility is expected to have a capacity of 150 megawatts of solar panels a year, could go online as soon as 2013.[428]
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