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 Sellafield Sub Division. In accordance with that strategy, a System Based Inspection (SBI) was carried out on the High Level Waste Plant (HLWP), as planned, on 14-15th May 2019.
The purpose of this inspection was for ONR to examine whether the licensee’s safety case claims in respect of the HLWP line 2 containment have been adequately implemented. The areas targeted were those providing containment of Highly Active Liquor within the HLWP Line 2 Cells and Pipebridges.
ONR’s SBI process examines evidence to determine compliance against six Licence Conditions (LC). These LC’s, listed below, have been selected in view of their relevance to ensuring nuclear safety and provide a structured approach to determining whether the safety case has been implemented adequately through the system being inspected.
LC 10 requires SL to make and implement adequate arrangements for suitable training for all those on site who have responsibility for any operations which may affect safety.
LC23 requires SL to produce an adequate safety case to demonstrate the safety of its operations, and to identify the conditions and limits necessary in the interests of safety.
LC24 requires SL to ensure that all operations which may affect safety are carried out in accordance with written instructions.
LC27 requires SL to ensure that a plant is not operated, inspected, maintained or tested unless suitable 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, so far as is reasonably practicable, that radioactive material and radioactive waste on the site is at all times adequately controlled or contained so that it cannot leak or otherwise escape from such control or containment.
Based upon the areas sampled I judge that the safety case requirements for the HLWP line 2 containment have been adequately implemented.
For LC10; I sampled the training of an operator and five maintenance engineers associated with operational movement of HAL and maintenance of the pre-selected safety mechanisms. From the evidence provided I was satisfied that individuals sampled had completed the required training requirements and were deemed suitably qualified and experienced for those tasks. I therefore judge that the required standard is met and an inspection rating of Green (no formal action) is appropriate against LC10.
For LC23; I was satisfied that the safety case clearly identifies appropriate limits and conditions to protect against the selected faults identified within the safety case. During the plant visit, the SL operational employees within the HLWP control room were able to clearly articulate the Operating rules associated with the HAL and showed knowledge of the safety case. Based on the evidence sampled, I judge that the required standard is met and an inspection rating of Green (no formal action) is appropriate.
For LC24; I was satisfied that the associated operating and maintenance instructions were adequate to ensure compliance with the limits and conditions identified in the safety case. I therefore judge that the required standard is met and an inspection rating of Green (no formal action) is appropriate.
For LC27; I was satisfied that the appropriate Safety Mechanisms (SM), Safety Related Equipment (SRE) and Safety Features (SF) equipment had been identified within the safety case and had been correctly designated. I therefore judge that the required standard is met and an inspection rating of Green (no formal action) is appropriate.
For LC28; prior to the inspection I requested the last completed maintenance tasks for six safety mechanisms. The maintenance records where available for all the above safety mechanisms with the exception of the coaxial stainless steel HAL pipebridge pipework as this was classed as non-maintainable. For the remaining safety mechanisms the maintenance records were sampled for completeness and consistency with the safety case requirements and no shortfalls were identified. I therefore judge that the required standard is met and an inspection rating of Green (no formal action) is appropriate.
For LC34; from the information provided, I was satisfied that the appropriate measures were in place to prevent and manage the leakage and escape of radioactive material in connection with the handling of HAL on the HLWP Line 2. I therefore judge that the required standard is met and an inspection rating of Green (no formal action) is appropriate.
The intervention was performed in line with ONR's guidance requirements (as described in our technical inspection guides) in the areas inspected.
From the evidence gathered during this intervention, I do not consider there to be any matters that have the potential to impact significantly on nuclear safety.
At present, no additional regulatory action is needed over and above the planned interventions within the Spent Fuel Management Operating Unit at the Sellafield Nuclear Site as set out in the Integrated Intervention Strategy, which will continue as planned.