This intervention was to undertake compliance inspections at EDF Energy Nuclear Generation Limited’s Torness power station, and formed part of the ONR Torness Integrated Intervention Strategy (IIS) for 2018/19.
The ONR nominated Torness site inspector, together with a specialist mechanical engineering inspector conducted the Systems Based Inspection of System 4, the Auxiliary Cooling System (ACS). The ACS consist of three sub systems:
Systems based inspections examine evidence to determine compliance against five key Licence Conditions selected to help determine whether the safety case requirements of the system concerned are adequately implemented.
ONR inspectors also attended an ‘Outage Intentions meeting’ between and Torness management concerning the outage of Torness Reactor 2 planned for September 2018. I also reviewed arrangements made by the site to improve the safety of staff accessing roofs in response to a fleet-wide ‘mandatory evaluation’ (MEVL).
From our inspection, we judged on the basis of our sample that the auxiliary cooling systems met the requirements of the safety case and were adequate.
Torness nuclear power station demonstrated that it has arrangements in place to ensure that the ACS is inspected, maintained and operated in accordance with its safety case. The arrangements sampled and examined by ONR complied with NGLs legal duties in the areas sampled during the inspection.LC10 Training - We examined the training records of three personnel involved in maintenance and inspection activities associated with the gas circulator auxiliaries cooling system (CACS). We judged that the personnel undertaking and supervising these activities were suitably qualified and experienced. We therefore assigned a rating of Green (No formal action) for LC10 compliance.
LC23 Operating Rules - The technical specification and surveillance schedules adequately specified the limits and conditions of operation (LCO), reflecting those specified in the safety case update documents (SCUDs). In addition the technical specifications and associated technical commentaries demonstrated that the limits and conditions of operation specified in the safety case. We therefore assigned a rating of Green (No formal action) for LC 23.
LC 24 (Operating Instructions) - We examined daily and per shift activities ensuring compliance with the technical specification. These were enabled through a number of station operating instructions and record log sheets. Also examined were technical specification compliance tables demonstrating the acceptable configuration of the ACS each reactor quadrant. Through our examination of these procedures we were content that the requirements of the technical specification were adequately confirmed. We therefore assigned a rating of Green (No formal action) for LC 24.
LC 27 (Safety Mechanisms, Devices and Circuits) - A presentation had been developed to enable ONR to understand NGLs LC27 compliance arrangements. The presentation detailed that LC27 compliance arrangements was managed through there technical specifications, (LC23), technical specification surveillance operating instructions (LC24) and maintenance arrangements (LC 28). The presentation demonstrated that appropriate checks were undertaken ensuring that operations were not undertaken unless the appropriate configuration and number of ACS were available in accordance with the technical specification. We judged therefore, that a rating of Green (No formal action) was appropriate for LC 27.
LC 28 (Examination, Inspection, Maintenance and Testing) - We sampled the licensees maintenance arrangements through interrogating the licensees computer based maintenance system. We confirmed that the ACS was regularly inspected and maintained.
We sampled three work order cards and associated inspection and maintenance procedures. We examined all three and were content that generally all had been completed appropriately. It was of particular note that two of the WOC were completed by contractors and these were considered to be particularly well completed. We were content that the evidence presented and examined confirmed that maintenance and inspection was being appropriately undertaken so we considered a rating of Green (No formal action) was merited against this License Condition.
This meeting was to discuss the key safety-related maintenance tasks to be completed during the statutory (LC30) outage of Torness Reactor 1 later in 2018, the safety of those conducting the outage, and to plan arrangements for liaison between EDF and ONR during its progress.
I reviewed arrangements made by Torness to comply with a company-wide ‘Mandatory Evaluation’ (MEVL) concerning safe access to roofs. I reviewed the arrangements made to assess roof safety and introduce controlled access to certain roofs where there are risks such as fragile materials. I was broadly satisfied with the overall approach taken, although it is clearly still being refined and solutions selected for individual roof spaces may merit reviewing with experience.
After considering all the evidence examined during our sample inspections, undertaken against LCs 10, 23, 24, 27 and 28 we judged that the ACS (System 4) met the requirements of the safety case.
There were no findings from this inspection that could significantly undermine nuclear safety. At present, no additional regulatory action is needed over and above the planned interventions of Torness nuclear power station as set out in the Integrated Intervention Strategy, which will continue as planned.