Reactors 1 to 4 at Fukushima Daiichi are highly likely to be written off, Tokyo Electric Power Company (Tepco) has said. The fate of undamaged units 5 and 6 may lie in the hands of local residents as may plans for new units.
The company has previously avoided speculation on the future of the reactors, despite the serious damage obvious from their external appearance. It is thought that units 1, 2 and 3 have suffered damage to their cores, but it will not be known how serious this is until the units are fully stabilised and can be examined in detail.
Despite unit 4 being out of service at the time of the tsunami, it has suffered serious damage to the reactor building due to a hydrogen explosion and fires in the vicinity of the used fuel pond. It is possible that fuel there has been damaged.
The announcement by Tepco's chairman Tsunehisa Katsumata today surprised no-one in noting that in light of the objective facts there is a high probability that the units will be decommissioned.
Reactors 5 and 6, on the same site but about 200 metres to the north, were shut down during the natural disasters and remained safe throughout although they too lost power for a time. Their operational fate is likely to rest in the hands of local people, who will surely be consulted on the continuation of nuclear power generation.
The residents evacuated from the vicinity of the power plant would naturally include thousands of nuclear plant workers, as well as their families and friends. Nuclear power would be the primary employer in the area, especially considering the Daini plant with four units only ten kilometres to the south. In real uncertainty however are former plans for nuclear expansion in Fukushima prefecture, despite the need for new large-scale low-carbon power having increased with the expected loss of the four Daiichi units.
Tepco had planned to construct two 1380 MWe Advanced Boiling Water Reactors at Fukushima Daiichi and the start of work on these was slated for 2012. This was a delayed date as a result of additional earthquake engineering flowing from what the company learnt during a July 2007 earthquake that hit similar reactors at Kashiwazaki Kariwa. Tepco contracted for 1600 MWe of new coal generation and 4500 MWe of gas to bridge the supply gap.
Further, Tohoku Electric Power Company had begun to plan for a large power reactor for the town of Namie, near Minamisoma city about 15 kilometres north of the Daiichi plant. Construction on this was pencilled in for 2017, but it can be safely said that local considerations will play a major part in future decisions.
In total, the existing units together with these plans would have seen some 13 large commercial nuclear reactors generating around 12,000 MWe - to produce around 7.5% of Japan's electricity - in the space of just 25 kilometres of coastline.
Nuclear provides about 30% of Japan's power overall and the country has not announced any change to plans that would see this grow to 40% by about 2017.
Researched and written
by World Nuclear News