Executive summary
Date(s) of inspection:
- September 2022
Aim of inspection
ONR have been undertaking a rolling series of reactor chemistry inspections, since 2010, with the aim being to conduct a chemistry focussed inspection at each site around every 3 years. Hartlepool was last inspected under this programme in June 2018. The focus of these inspections is on operational chemistry control and management. This inspection will focus on primary coolant and pond chemistry, seeking confidence that the licensee is exercising adequate control of station chemistry to minimise materials degradation, radiation exposure and the generation of radioactive waste. Staff resource, competence and relevant procedures may also form part of the inspection, along with visibility of the chemistry safety case. This inspection may also sample aspects of NGL’s response to the fleet enforcement letter served following the feedwater chemistry control event at DNB. The inspection will focus on i) technical governance implementation to station operating rules and instructions ii) maintenance of relevant plant and condition (with duties for end of generation considered) and iii) capability of the chemistry function and advocacy of chemistry to other functions on site. The main License Conditions (LC) of relevance to the inspection will therefore be aspects of LC10 (training), LC 12 (SQEPs and DAPs), LC23 (operating rules), LC24 (operating instructions) and LC28 (examination, inspection, maintenance and testing). It is anticipated that the inspection will be rated against LCs 23 and 28. The inspection will be performed in line with ONR’s guidance (as described in our technical inspection guides).
Subject(s) of inspection
- LC 23 - Operating rules - Rating: GREEN
- LC 28 - Examination, inspection, maintenance and testing - Rating: GREEN
Key findings, inspector's opinions and reasons for judgement made
This was one in a series of reactor chemistry inspections conducted at each EdF Nuclear Generation Ltd (NGL) site approximately every 3 years. The focus of these inspections is on operational chemistry control and management. This inspection specifically considered:
- technical governance implementation to station operating rules and instructions (focusing on primary coolant gas and pond chemistry control); and
- the condition of plant required to maintain chemistry control and plant health assessment.
I considered the following Licence Conditions (LCs) in relation to gas and pond chemistry:
LC 23 (Operating Rules)
I reviewed implementation of control parameters for primary coolant gas and pond chemistry, identifying appropriate visibility of control parameters from technical governance in station documentation. I also sampled evidence of control of gas and pond chemistry. Station was able to demonstrate good compliance with chemistry control parameters over the previous 12 months, with only minor perturbations observed. I challenged the scope of Living Safety Case Documents (LSD), with no apparent consideration of boron requirements to maintain criticality control or links to chemistry technical governance. I was satisfied this was however reflected in station operating instructions and consider this a minor issue to be resolved as part of routine document revision. Based on my sample, I was content station was controlling chemistry in line with the requirements of the safety case and I therefore judged a rating of GREEN (no formal action) to be appropriate for LC 23.
LC 28 (Examination, Inspection, Maintenance and Testing)
I sampled station’s arrangements for maintaining plant health of B22 (Gas Bypass Plant) and A14 (Pond Water Treatment). I also undertook a walkdown of parts of these systems and the sodium hypochlorite dosing plant. System health metrics were green for A14 over the previous six months, with a recent defect reduction drive noted. I observed fluctuating amber/white scoring for B22 however, attributed to degraded physical condition. Higher priority defects were either addressed or within permitted timescales for both systems however. I sampled Equipment Reliability Reviews (ERR) and Lifetime Asset Management Plans (LAMP) for both B22 and A14. While ERRs were available for B22 and A14, I note that ERRs had been subject to delays of up to 12 months across systems. Station attributed this delay to reactive work for double reactor outages and pressure safety system regulations challenges. I judged that clear conclusions were not presented for the ERR for B22. I have shared these observations with the nominated site inspector. During my plant walkdown I observed the pond system to be in reasonable condition. Chemistry laboratories also appeared in good condition, with clear investment in analytical equipment. The gas bypass plant however was experiencing an emergent townswater leak. Long-standing ground water ingress challenges were also apparent. While the townswater leak was pending repair, I highlighted ground water ingress may become more impactful as station ceased generation and civil structures cool. Externally, I observed white deposit on pipework in the hypochlorite plant indicating leaks, while external connecting coaxial hoses appeared to have been subject to UV degradation. While I do not consider this to be a nuclear safety risk, I judge this represents tolerance of degraded plant health condition and a potential risk to conventional health and safety. I have therefore raised a Level 4 Issue (RI-11020) for station to review and defects on the hypochlorite plant, and ensure degraded pipework remains safe and able to perform its function. Based on my sample, I judged a rating of GREEN (no formal action) was therefore warranted for LC28.
Conclusion
Based on my sample, I was content station was controlling chemistry in line with the requirements of the safety case and I judged a rating of GREEN (no formal action) to be appropriate for LC 23. However, I identified a number of low level issues relating to LC 28 and have raised one Level 4 Regulatory Issue RI-11020. I am content these do not undermine nuclear safety however and judge a rating of GREEN (no formal action) to be warranted for LC 28. I consider these low level issues may indicate a tolerance to plant degradation however. These items will therefore be followed up by the nominated site inspector as part of a planned nuclear safety culture inspection at Hartlepool.