There is no need for the United Kingdom to curtail the operation of its nuclear power power stations in the wake of the situation at Japan's Fukushima-1 facility, nor should it change its plans for new nuclear plants. So says an interim report from the U.K.'s chief inspector of nuclear installations, Mike Weightman. The main arguments that Weightman offers for his conclusions are the unlikelihood of similar seismic activity in the United Kingdom—it is 1000 miles from the edge of a tectonic plate—and the fact that all of its 19 reactors are of a different design from those at Fukushima. He has made 26 recommendations to ensure that any relevant lessons are learned from Japan's experience. Weightman's conclusions differ markedly, however, from those of other countries such as Germany, where an ethics panel has recommended shutting all plants by 2021, Italy, where new plant construction is on indefinite hold, and the United States, where the Nuclear Regulatory Commission has deemed it too early to make any firm conclusions.
The U.K. government ordered a review the country's nuclear policies in the days following March's disastrous earthquake. A full report is due in September, but Weightman was tasked with presenting interim findings in May so that other authorities can react to them.
In his report, Weightman pointed out that the magnitude-9 earthquake and subsequent 14-meter tsunami inflicted on Japan are "far beyond the most extreme natural events that the U.K. would be expected to experience."
But bearing in mind the impact on the Fukushima plant of flooding and the loss of grid power, the report's recommendations include reviews by the nuclear industry of their facilities' resilience to flooding and reliance on off-site infrastructure (i.e. grid power).
At Fukushima, the fact that so many reactors on the same site were in a dangerous condition caused huge problems for emergency staff. U.K. plans for new nuclear plants all involve sitting them at existing nuclear facilities. Weightman recommended that the safety case for new nuclear plants should demonstrate the ability to deal with multiple serious events. The report also recommends reviews of emergency response procedures and training, bearing in mind the extended length of time it is taking to get the Fukushima plant back under control.
None of Britain's reactors are of the boiling water design (BWR) used at Fukushima. One plant (Sizewell B in Suffolk) is a pressurized water reactor but it is much more modern, having been completed in 1995, and Weightman declares it "one of the most advanced PWRs operating in the world." The rest of the country's reactors are gas-cooled. The report points out that the cores of such reactors have a lower power density and higher heat capacity, so following a loss of coolant they react much more slowly than BWRs, giving operators more time to get the situation under control. In addition, without water as a coolant, they do not produce explosive hydrogen gas when they overheat.