The recent internal leak of nuclear waste of 20 tonnes of nuclear waste at Sellafield’s THORP facility went undetected for at least three months, an investigation has found:
The cause of the failure dates back to a change in design intent when changes to the restraint mechanisms on these suspended tanks were introduced that allowed greater stresses to be exerted on associated pipework than had been anticipated.
There is some evidence to suggest that the pipe may have started to fail in August 2004. Failure of the pipe (at which point significant amounts of liquor started to be released into the cell) is believed to have occurred in mid January 2005.
However, in the period between January 2005 (and perhaps earlier) and 19 April 2005, opportunities, such as cell sampling and level measurements, were missed which would have shown that material was escaping to secondary containment. While the failure could not have been prevented at this stage, had these opportunities been taken the quantity of liquid released could have been significantly reduced. (British Nuclear Group press release)
Irish Environment Minister Dick Roche had this to say about the latest revelation:
"The latest information is a further damning indictment of the THORP Plant and Sellafield’s Safety Record"The Minister said, "The pattern with Sellafield is well established and consistent. A serious incident occurs, the investigation reveals serious safety failures and weaknesses, recommendations are drawn up and implemented, and further assurances given that the plant is safe. However, this pattern is untenable and the safety record at the plant has given the Irish Government serious cause for concern for some time. This latest information serves only to increase the concerns of the Government and to reinforce our efforts to secure the safe and orderly closure of Sellafield." (Irish Government press release)