- Site: Heysham 1
- IR number: 21-039
- Date: June 2021
- LC numbers: 7, 14, 23
Executive summary
Purpose of Intervention
This was a planned inspection at EdF Energy Nuclear Generation Ltd’s (NGL’s) Heysham 1 (HYA) 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 inspection programme contained in the HYA Integrated Intervention Strategy (IIS) for 2021/22.
Interventions Carried Out by ONR
NGL has previously made commitments to implement chemistry technical governance in station safety case documentation Within the chemistry function, technical governance documents are known as British Energy Operating Manuals (BEOMs). A number of other Company Technical Standards (CTS) technical governance documents are also of relevance to chemistry. The production of technical governance is driven by the Central Technical Oversight (CTO) function at Barnwood. This has been the subject of previous inspections ). Technical governance revision however requires station input, with implementation the responsibility of stations. The input of station to technical governance revision and subsequent implementation formed the focus of this intervention. The inspection was therefore rated against LC14 and LC23. Given proximity to end of generation (EoG) at HYA and challenges related to Carbon Deposition (CD), the inspection was targeted towards primary coolant chemistry and chemistry control beyond the end of generation.
While not rated, ONR has also recently challenged event reporting within the chemistry function at NGL. This intervention therefore also sought to sample station processes for event reporting and application of new guidance produced by CTO within the chemistry function to ensure effective learning from experience (LFE) in line with LC7 and SAP MS.4.
Explanation of Judgement if Safety System Not Judged to be Adequate
N/A.
Key Findings, Inspector's Opinions and Reasons for Judgements Made
Licence Condition 14 (Safety Documentation)
Based on my sample, I am content that HYA is appropriately providing input to the revision of technical governance. HYA was able to identify relevant processes for technical governance revision and forums for their input to this. I observed active input from HYA with regards to driving improved understanding of CD and associated operating rules (BEOM/211), progress with respect to production of CD questionnaires and updated monitoring arrangements for biofouling of sea water cooling systems. A rating of GREEN (no formal action) was therefore judged appropriate for LC14.
Licence Condition 23 (Operating Rules)
With regards to LC23, I sampled HYA’s implementation of technical governance into the station safety case. Specific to primary gas chemistry, I identified positive implementation of developed understanding and operating rules for mitigation of CD in station procedures. Related, I observed implementation of revised technical governance for CD trending and analysis. From my sample, I also judged chemistry control compliance with technical governance to be adequate. While I identified gaps with respect to implementing links in Living Safety Case Documents (LSDs) to BEOMs, I am content this will be addressed by separate CTO action. I noted good practice with respect to HYA development of a chemistry safety case ‘route map’. A rating of GREEN (no formal action) was therefore assigned for LC23.
Licence Condition 7 (Incidents on the Site)
While not rated, I also sampled HYA’s event reporting process from a chemistry perspective. Based on discussions, I was content HYA is appropriately raising condition reports (CRs) to enable effective trending of chemistry events. Additionally, I was content that HYA has increased awareness of event reporting requirements via the INF1 route for chemistry as a result of previous ONR challenge. I will therefore seek to keep a watching brief in this regard as part of routine interactions with NGL.
Conclusion of Intervention
There are no findings from this inspection that could significantly undermine nuclear safety and no change is necessary to the planned interventions and inspections. I have however identified two topics for follow up in routine engagements. These relate to:
- CTO action to improve links between chemistry technical governance and LSDs; and
- Maintaining a watching brief on sentencing of chemistry related events via the INF1 route.