Mea culpa

日期:2017-12-04 03:18:24 作者:娄情倦 阅读:

By Rob Edwards JUST too trusting. That is the verdict of Britain’s safety watchdog on its own relationship with the UK Atomic Energy Authority. Last week, the Health and Safety Executive admitted to New Scientistthat it had misjudged problems at the authority’s nuclear plants. The HSE, through its Nuclear Installations Inspectorate, is responsible for ensuring the safety of workers at Britain’s nuclear facilities. It has been sending inspectors to UKAEA sites since 1975, although it was not until 1990 that they gained legal power to control the sites’ activities under the Nuclear Installations Act. The five UKAEA sites now licensed under the act are Dounreay in Caithness, Harwell and Culham in Oxfordshire, Winfrith in Dorset and Windscale, part of the Sellafield site in Cumbria. According to Laurence Williams, the HSE’s chief inspector of nuclear installations, these sites were not a high priority for the HSE before 1995. But he now recognises that this was a mistake. “We underestimated these sites,” he told New Scientist. “With hindsight, we were too trusting.” Chastened by what he discovered at Dounreay since he became chief inspector in March this year, Williams is now setting up a new unit of inspectors. Last week’s report, the result of a comprehensive safety audit of Dounreay by 15 inspectors from the HSE and one from the Scottish Environment Protection Agency, was triggered by an accident in May when part of the site’s power supply was disrupted by a digger damaging an underground cable. The report concludes that the UKAEA has been running plants “without clear knowledge of some of the risks” and makes 143 recommendations for change. The report alleges that some laboratories at Dounreay that are severely contaminated with radioactive material have been abandoned for many years, with no attempt to make them safe. Containment in laboratory 33, which contains radioactive debris from fast reactor research in the 1980s, is broken and ventilation ducts are “hanging loose”, the report reveals. Partitions meant to contain contamination at an old uranium processing plant are “held together with adhesive tape”. About 1000 radioactive fuel elements and tonnes of contaminated sodium and potassium alloy have been left in an experimental fast reactor since it closed in 1977. The walls, ventilation system and other equipment in one old research facility are “heavily contaminated” with plutonium. Cleaning up the facility becomes more dangerous with time, the report points out, because the plutonium decays into americium which emits gamma rays, the most damaging form of radiation. The UKAEA insists that its sites are safe and that it is cooperating fully with the HSE’s inspectors. “Our safety record is good but safety is a continually evolving process and we work with our regulators to maintain and improve our safety management and procedures across all our sites,