These shortfalls did not compromise either nuclear or radiological safety. Nickel nitrate, used in the treatment of effluent, is not radioactive, but is a hazardous substance and could cause harm to the health of a worker exposed to it.

To mitigate these risks, operations involving the chemical should be conducted in a glovebox to protect workers from any harmful health effects. In one facility on the site, contamination was found outside the glovebox area, which resulted in workers potentially being exposed to the chemical. A poorly designed and maintained glovebox appeared to have contributed to the contamination.

Ian Bramwell, ONR Superintending Inspector, said: “We will closely monitor Sellafield Limited to ensure the identified shortfalls are addressed and will not hesitate to take further action to bring about improvements if we need to do so.”

The first notice, served under Regulation 6 of COSHH, requires Sellafield Ltd to complete a suitable and sufficient assessment of the risks associated with the use of nickel nitrate by the end of October 2024. The second notice, served under COSHH Regulation 7, requires Sellafield Ltd to either prevent or, where this is not reasonably practicable, adequately control exposure of workers to nickel nitrate. Sellafield Ltd is required to do this by the end of March 2025.