Two improvement notices have been issued on a nuclear site due to breaches of hazardous chemical control regulations.

Sellafield failed to manage the risks of working with nickel nitrate and to prevent or adequately control the exposure of workers to this hazardous substance in one of its effluent facilities, the Office for Nuclear Regulation (ONR) found, resulting in the enforcement action being taken.

The failings constituted breaches of the Control of Substances Hazardous to Health (COSHH) Regulations 2002, but the shortfalls did not compromise either nuclear or radiological safety.

Used in the treatment of effluent – a word used to describe liquid waste – nickel nitrate is not radioactive but is hazardous and could harm an exposed worker’s health.

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 West Cumbrian site, contamination was found outside the glovebox area, which resulted in workers potentially being exposed to the chemical.

The ONR said a ‘poorly designed and maintained’ glovebox appeared to have contributed to this 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 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 Regulation 7 of COSHH, requires Sellafield to either prevent or, where this is not reasonably practicable, adequately control the exposure of workers to nickel nitrate.

Sellafield is required to do this by the end of March 2025.

Strict occupational hygiene controls will remain in place in the facility, monitored by an occupational hygienist, until full compliance with both improvement notices is achieved, the ONR added.

A spokesperson from Sellafield said ‘traces’ of nickel nitrate was found ‘outside of its primary containment cabinet’.

They added: “Following the inspection, enhanced monitoring and cleaning of the affected area was carried out.

“As with all site incidents, we are taking this extremely seriously.

“A formal investigation has been initiated to understand the root cause and to prevent this from happening again in future.

“Our regulator has been informed and we are working closely with them to bring about the required improvements in assessing and controlling exposure to nickel nitrate.”