System based inspection (SBI) at the BAE Systems Marine Ltd (BAESML) Barrow site
- IR number: 16-147
- Date: October 2016
- LC numbers: 10, 23, 24, 27, 28
Purpose of intervention
This was a system based inspection, (SBI) conducted jointly by ONR and the Defence Nuclear Safety Regulator (DNSR), of systems important to the control of reactivity at the BAE Systems Marine Ltd (BAESML) Barrow site, undertaken as part of the planned inspection programme for 2016/17.
Interventions Carried Out by ONR
Inspectors carried out an SBI of several safety systems in place to maintain criticality control during submarine build at the Devonshire Dock Complex (DDC). The two inspection teams involved ONR and DNSR inspectors, ONR specialist inspectors and DNSR support contractors. Two members of BAESML’s internal Nuclear Safety Regulation Department accompanied and facilitated the inspection.
Explanation of Judgement if Safety System Not Judged to be Adequate
The criticality controls inspected during this SBI were judged to be adequate.
Key Findings, Inspector's Opinions and Reasons for Judgements Made
The inspection team made the following findings in relation to the arrangements made under the relevant applicable licence and authorisation conditions:
- Training (No 10): We were satisfied that the site personnel were adequately trained in the operation / maintenance of the safety systems relating to criticality control.
- Operating Rules (No 23): We were satisfied that the safety case limits and conditions had been identified and were adequately implemented.
- Operating Instructions (No 24): We found that the operating instructions that we examined in support of criticality control were adequately implemented.
- Safety mechanisms, devices and circuits (SMDCs) (No 27): We found, that where applicable, the identified SMDCs were properly connected, identified and in good working order.
- Examinations, Inspection, Maintenance and Testing (No 28): We found that numerous systems existed to capture the maintenance and testing of safety system with criticality control functions. It was considered that the complexity and number of these systems introduces potential error traps in the interface, whereby maintenance work may be omitted and were not readily auditable. We did not identify any evidence that any of the systems examined showed any sign that maintenance had not been adequately conducted. These findings are consistent with previous inspections in this area and have already been recorded and tracked with an extant ONR regulatory issue.
- Leakage and escape of radioactive material and radioactive waste (No 34): Due to the phase of the build of the submarine this was deemed to be not applicable.
Conclusion of Intervention
Based upon the evidence examined during this SBI, we consider that BAESML has adequately implemented the safety case associated with criticality control. No new regulatory issues were raised during this SBI.