Monday, May 9, 2005 

At the Sellafield reprocessing plant, a leak in the process was spotted on April 19. The leak did not cause danger to people or the environment but it disturbed the normal operation of the plant.

Workers at the plant noticed a discrepancy in the amount of material being reprocessed that enters pipes that lead to a set of centrifuges and the amount of material actually arriving at the centrifuges. They used remote cameras to find the crack where the material was escaping; over twenty tonnes have leaked into a steel lined chamber.

The material, consisting of mostly uranium and some plutonium dissolved in nitric acid, would have been reprocessed in the centrifuges. The large stainless steel chamber that now contains the spilled material is too dangerous to enter due to radioactivity, though it poses no danger to those inside or outside the plant.

The plant has been shut down pending repairs.

The Thermal Oxide Reprocessing Plant, or THORP, recycles spent nuclear fuel from British AGR and PWR reactors. (Another plant reprocesses fuel from Britain’s older Magnox reactors). Nuclear fuel reprocessing recycles spent nuclear fuel, greatly reducing the amount of waste. The process is technically complicated and there is a political debate on its safety. Since the price of nuclear fuel is presently low, fuel produced by THORP has had problems competing in the market. Furthermore THORP has encountered some technical problems lately. There is discussion whether THORP should be allowed to continue in operation.

Sellafield is also the site of, amongst other things, a decommissioned nuclear power plant. Previously the site has also been the scene of the 1957 Windscale fire, the most severe nuclear accident on British soil.

On February 17, 2005, the United Kingdom Atomic Energy Authority reported 29.6 kg of plutonium was unaccounted for during audits at the facility. However, this is an error of 0.5%, and the IAEA allows a 1% error to allow for, e.g., mistakes on paper.