Office for Nuclear Regulation

Heysham 2 - SBI 12 inspection

Executive summary

Purpose of Intervention

This was a planned inspection of EDF Energy Nuclear Generations Ltd.’s (NGL’s) Heysham 2 power station, undertaken as part of the planned intervention strategy for the Operating Facilities Division (OFD) of the Office for Nuclear Regulation (ONR)

The work was carried out in-line with the planned inspection programme contained in the Heysham 2 Integrated Intervention Strategy (IIS) 

Interventions Carried Out by ONR

The Nominated Site Inspector for Heysham 2 Power Station, an ONR C&I Specialist Inspector and a C&I Associate Inspector performed a System Based Inspection (SBI) of the Fuelling Machine and Decay Store against its safety function. In this case, as the Decay Store has been the subject of a recent inspection, it was decided to focus this intervention on the Fuelling Machine. The inspection sampled the implementation of the licensee’s arrangements at Heysham 2 against the following License Conditions (LCs):

 The objective of the inspection was to determine whether the licensee’s arrangements were adequately implemented and in accordance with the safety case requirements of the system.

The intervention was performed in line with ONR's guidance requirements (as described in our technical inspection guides) in the areas inspected.

The nominated site inspector also undertook the following routine regulatory activities;

Explanation of Judgement if Safety System Not Judged to be Adequate

From this inspection, we judged from the evidence sampled that the safety provisions applicable to the Fuelling Machine met the requirements of the safety case.

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

For LC23 we sampled the implementation of limits and conditions for the safety case claims associated with on-load refuelling, off-load depressurised refuelling, dropped stringer reactor trip and the fuelling machine safety relief valve. We judged that the licensee could demonstrate that the limit and conditions were derived from the safety case and that the implementation was suitable and sufficient.

 For LC24, we sampled the quality plans for on load refuelling as these contained high integrity claims on the operators. We were content that the quality plans were adequate and developed with suitable rigour. We asked the licensee to consider whether the independent checking process in the CCR could be enhanced by implementing the methodology being used within the fuel route. 

For LC 28, we sampled maintenance records associated with the fuelling machine in-situ calibration of the differential pressure switch, mechanical hoist height switches and the PSSR thorough examination of the fuelling machine pressure relief valve.

For LC34, we sampled the safety justification which allowed an increase (2% to 5% per day) to the allowable gas release from the fuelling machine during routine operations. We judged that the licensee had followed its processes adequately and there was no notable increase in the risk or magnitude of a radiological release from the fuelling machine.    

We noted a proactive ageing and obsolescence management scheme in place on the Fuelling Machine. We also noted that the system engineers were highly knowledgeable in their owned systems and the succession planning on knowledge management appeared to be a high priority.

During the plant walk-down, we noted that the housekeeping arrangements met the standards and expectations the licensee aspires to.

In summary, the SBI of the Fuelling Machine and Decay Store, inspected for Licence Conditions 10, 23, 24, 27, 28, and 34, is rated as Green.

Conclusion of Intervention

After considering the evidence sampled during the inspection against Licence Conditions 10, 23, 24, 27, 28 and 34, we concluded that the licensee complied with its legal duties regarding the Fuelling Machine and Decay Store and met the requirements of the safety case. This was communicated to Station management at the close of the inspection.

There are no findings from this intervention that could significantly undermine the nuclear safety at Heysham 2. At present, no additional regulatory action is needed over and above the planned interventions of Heysham 2 as set out in the Integrated Intervention Strategy, which will continue as planned.