Office for Nuclear Regulation

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Heysham 1 Power Station – SBI 016 - Irradiated Fuel Disposal Facility

Executive summary

Purpose of intervention

The purpose of this intervention was to undertake a system based inspection (SBI) at EdF Energy Nuclear Generation Ltd’s (EdF NGL’s) Heysham A (HYA) nuclear power station.  The system inspected was System 16 – “Irradiated Fuel Dismantling Facility” (IFDF) and the inspection was conducted in line with the inspection programme contained in the HYA integrated intervention strategy (IIS) for 2015/2016.

Interventions Carried Out by ONR

The outgoing Office for Nuclear Regulation (ONR) Fuel Performance Inspector (within ONR’s Civil Nuclear Reactor Programme – CNRP), together with the incoming inspector and the Nominated ONR Site Inspector (referred to as we throughout this report), conducted a SBI of System 16 (Irradiated Fuel Dismantling Facility – IFDF) at HYA nuclear power station.  Through examination of this system, we performed compliance inspections against the following licence conditions: - LC 10: Training; LC 23: Operating Rules; LC 24: Operating Instructions; LC 27: Safety Mechanisms, Devices and Circuits; LC 28: Examination, Inspection, Maintenance and Testing and LC 34: Leakage and Escape of Radioactive Material and Radioactive Waste.  The inspection was based on sampling the implementation of the arrangements in place at the station against each licence condition.

Explanation of Judgement if Safety System Not Judged to be Adequate

From our inspection, we judged that overall the IFDF system met the requirements of the safety case and is adequate.

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

LC 10 (Training) – For three of the key roles, associated with the operation of the IFDF at HYA, we requested the “Role Profiles,” in order to understand the essential training that personnel, undertaking each of these roles, have to undertake and remain in date for.  We then randomly sampled two individuals within each role and examined their training records to ensure all were in date for all essential training associated with their role.  All records examined were found to be in order and therefore we judged that compliance with LC10 was adequate with an IIS rating of 3.

LC 23 (Operating Rules) – Operating Rules are defined by the safety case and we noted that the safety case for the IFDF had not been revised since 2000.  Whilst work has commenced on a review and update of the safety case, this work is not due to be completed until 2018.  In addition, the current safety case represents an operating mode that was not adopted at HYA (i.e. on-load refuelling) and hence the safety margins for the actual plant operating mode (off-load depressurised refuelling) are not adequately quantified.  In light of this we consider that in this area compliance with LC23 is below the expected standard with an IIS rating of 4.  Accordingly an action (ONR Issue 4149) has been raised on the Licensee to accelerate its current safety case review or justify the currently planned completion date of 2018.

LC 24 (Operating Instructions) – Picking a random sample of spent fuel disposals we examined completion of the required paperwork for these fuel disposals.  Whilst we judged that overall the fuel disposal procedures were adequate and are being adhered to, we also identified several potential areas for improvement.  Since the licensee readily accepted our findings in this area and is already proposing to revisit its procedures, we were content to allow the licensee to follow this up (i.e. no further regulatory action is considered to be necessary at this juncture).  Accordingly we considered compliance with LC24 to be adequate with an IIS rating of 3.

LC 27 (Safety Mechanisms, Devices and Circuits) – Under this licence condition we confirmed that the licensee has a list of all safety critical equipment associated with the IFDF (i.e. the licensee clearly recognises the equipment of importance to safety).  We then confirmed that this safety critical equipment has maintenance routines specified on the Station Maintenance Schedule.  Finally, we noted that the Technical Specifications (Tech Specs) provide instructions on the actions necessary if the safety critical equipment is in a degraded state.  Although we noted that IFDF cell entries are not protected by a gamma interlock, which would be the expectation for a modern plant, we judged that the current mechanical interlocks and administrative controls provide adequate protection against inadvertent worker entry into the IFDF cell whilst irradiated fuel is present. Consequently we judged that compliance with LC27 was adequate with an IIS rating of 3.  Notwithstanding this, we advised the license that during the safety case review, retrospective fitting of a gamma interlock should be considered as part of a gap analysis against modern standards.

LC 28 (Examination, Inspection, Maintenance and Testing) – We randomly sampled the maintenance instructions and records for a number of key IFDF components and found a number to be incomplete with missing measured values and non-confirmation of completion of certain steps.  In addition there was a lack of clarity on follow-up actions where anomalies had been identified during the maintenance work.  We therefore judged compliance with LC28 to be below the standard expected with an IIS rating of 4.  In light of this and previous similar findings under LC28, ONR Issue 4150 was raised on the Licensee to confirm how they intend to address this shortfall.

LC 34 (Leak and Escape of Radioactive Material and Radioactive Waste) – During the plant walk-down, at the bottom of the Element Reception Tube (ERT) gallery, we noted two IFDF drain pipes which were not labelled and evidence of damp on the wall from which they emerged.  It was unclear whether the pipework had a potential to contain radioactive material and hence present a hazard if the pipework were to leak (in which case personnel cleaning the leak could inadvertently be exposed to radioactive material).    The wall was surveyed by the Licensee the following day and no evidence of contamination was found.  Notwithstanding this, other potential areas of leak and escape of radioactive material were well managed and therefore overall we judged that compliance with LC34 was adequate with an IIS rating of 3.  The nominated site inspector will follow up the labelling of the two pipes as part of normal regulatory business.

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

Conclusion of Intervention

After considering all the evidence examined during our sample inspections, undertaken against LCs 10, 23, 24, 27, 28 and 34, we considered that the IFDF system (System 16) met the requirements of the safety case.

ONR Issue Numbers 4149 and 4150 were raised to address shortfalls in the current safety case and maintenance record arrangements.  These will be monitored as part of normal regulatory business.

Notwithstanding the above issues, there are no findings from this inspection that could significantly undermine nuclear safety on the station at this time. Consequently, no additional regulatory action is needed over and above the planned interventions of Heysham 1 power station as set out in the Integrated Intervention Strategy, which will continue as planned.