Statement of nuclear incidents at nuclear installations: fourth quarter 1994

摘要

Four nuclear incidents at installations in the United Kingdom during the fourth quarter of 1994 are reported. Reheat cracking occurred at four non-stressed-relieved welds in steam pipework at one of the two AGRs at the Dungeness B power station. Repairs have been carried out and an extensive inspection programme undertaken for welds most at risk on both reactors. The event was classified as Level O on the International Nuclear Event Scale. A small quantity of oil with a very low level of radioactive contamination was discharged into the air from the Hartlepool nuclear power station. Contamination was confined to land belonging to the utility, Nuclear Electric. The oil was traced to the vacuum services plant and measures necessary to prevent a further incident are being established. The Nuclear Installations Inspectorate was satisfied that there was no disregard of safety and the event has been classified as Level 1. A higher than normal level of CO(sub 2), 2%, was discovered in a stairwell in a reactor building at the Dungeness B AGR station. No radioactivity was detected, the source of the leak was found and the event classified as Level O. Appropriate actions have been taken to prevent a recurrence. The final incident arose at the British Nuclear Fuels Sellafield Site. A bursting disk on an inactive compressor cooling circuit burst releasing ten cubic metres of clean water into the building operating area. The water became contaminated by 10(sup 9) to 10(sup 10) Bq of beta/gamma radioactivity under a lead shielded area of floor and as a consequence of a drain blockage overflowed onto a site road. Decontamination of about 4 m(sup 2) of road was required. No personnel were affected by radioactivity and the incident was classified as Level 1. (UK). (Atomindex citation 26:054839)