Rolls-Royce Submarines Ltd (RRSL) has complied with an ONR improvement notice served on 29 May 2020.
The notice was served after RRSL operators brought 21 units of fissile material into the facility – thereby exceeding the limit defined within the safety case, and set out in the Criticality Control Certificate for the facility.
Significant safety margins remained in place at the plant, and public and worker safety was not compromised.
ONR is now satisfied RRSL has met the requirements of the notice and the necessary improvements have been made at its Derby site.