Office for Nuclear Regulation

System Based Inspection (SBI) of Civil Assets and Bridges (INF09) on Sellafield Ltd.’s nuclear licensed site at Sellafield, Cumbria

Executive summary

Purpose of intervention

The Office for Nuclear Regulation (ONR) undertakes all regulatory interaction with the Sellafield site licensee (Sellafield Limited, SL) against a strategy defined by the ONR’s Sellafield Programme.  In accordance with that Strategy, a system based inspection of civil assets and bridges was planned for June 2015.  The purpose of this inspection is for the ONR to examine whether the licensee’s safety case claims in respect of this system have been adequately implemented on plant.

This inspection activity targeted the civil structures associated with roadbridges and pipebridges since the failure of these assets could have a significant detrimental impact on the provision of those utilities (e.g. water, steam, electrical supply) important to safety, as well as having the potential (in some limited cases) to lead to a radiological release.

Our system based inspection process examines evidence to determine the compliance status against six key licence conditions (LCs). These licence conditions (listed below) have been selected in view of their importance to nuclear safety and in supporting a structured approach to determining whether the safety case has been implemented adequately through the system being inspected.

Interventions Carried Out by ONR

LC10 requires SL to make and implement adequate arrangements for suitable training of those who have responsibility for any operations that may affect safety.

LC23 requires SL to produce adequate safety cases to demonstrate the safety of its operations, and to identify operating conditions and limits necessary in the interests of safety.

LC24 requires SL to make and implement adequate arrangements for the provision of suitable written instructions for undertaking any operation that may affect safety.

LC27 requires SL to ensure that, before a system is operated, inspected, maintained or tested, all safety mechanisms, devices and circuits are properly connected and in good working order.

LC28 requires SL to make and implement adequate arrangements for the regular and systematic examination, inspection, maintenance and testing of all plant which may affect safety.

LC34 requires SL to ensure that its radioactive material and radioactive waste is at all times adequately controlled and contained, and that no leak or escape of that material or waste can take place without being detected.

I carried out a two-day, on-site, system based inspection of civil assets and bridges. I was assisted by technical support from two civil/structural engineering specialists and ONR colleagues.  The inspection comprised discussions with SL staff, physical viewing and inspections of targeted civil assets and bridges, and reviews of Sellafield Ltd.’s records and other safety related documentation.

Given the nature of the system being examined, it was my opinion that LCs 27 and 34 were not relevant to this system as the civil structures do not contain safety mechanisms etc and are not claimed to deliver a role regarding leakage and escape. Consequently, compliance against only LCs 10, 23 and 28 was examined during this inspection.

Explanation of Judgement if Safety System Not Judged to be Adequate

The system was judged to be an adequate implementation of the safety case.

Key Findings, Inspector's Opinions and Reasons for Judgements Made

From the evidence I examined during this inspection, I consider that SL has implemented adequately those safety case claims that relate to civil assets and bridges. I have, however, identified one specific area for improvement, which relates to the absence of crash barrier protection for some pipebridge towers. Consequently, it is my opinion that a rating of 3 (adequate) is appropriate for LCs 10 and 23, whilst for LC 28 a rating of 4 (below standard) was justified.

 I have raised an ONR Regulatory Issue in order to track SL’s progress regarding the protection of pipebridge structures against impacts by vehicles etc.

Conclusion of Intervention

 I consider that the licensee has a good knowledge of the physical condition of these civil assets and bridges, and has in place appropriate management controls to ensure on-going safety.

I have, however, identified one specific area for improvement, which relates to crash barrier protection for pipebridge towers.  I have raised an ONR Regulatory Issue in order to track SL’s progress in this regard.