REPROCESSING operations have been halted at Sellafield while safety work is carried out.

Some radiation detectors were found to be "not fit for purpose" during an inspection last month. Reprocessing operations have been stopped while the issue is addressed. They are expected to resume in two to four weeks.

A spokesman said: "Safety and security are our overriding priorities at Sellafield. We can confirm that during preparation for an inspection of the criticality detection system in the Magnox Reprocessing plant, an issue was identified. We immediately initiated a further review of the system, which found some detectors within the enclosed cells in the building were not fit for purpose. The review found all other cell detection systems within the facility to be adequate.

“A programme of work is under way to address the issue. Additional safety measures have been put in place. These include reducing the numbers of people accessing the area and deploying back-up monitoring equipment.”

The issue dates back to the 1980s when work was carried out to replace the building’s criticality system and the original detectors were replaced with more sensitive equivalents. "Because of the placement of the detectors in the cells in question, they were prone to producing spurious or false alarms, owing to high background radiation in the area," said the spokesman.

"At the time, the most suitable solution was to include additional lead shielding around the detectors. While that was an acceptable course of action in the 1980s, it would not be best practice today. Therefore, the detector system is no longer considered fit for purpose."