- Site: Heysham 1
- IR number: 20-008
- Date: June 2020
- LC numbers: 28, 34
Executive summary
Purpose of Intervention
The purpose of this intervention was to undertake a planned licence condition (LC) compliance inspection at EDF Nuclear Generation Limited’s (NGL’s) Heysham 1 power station in line with the relevant site inspection plan. The inspection was undertaken by a project inspector and the nominated site inspector (part time); it was undertaken remotely due to constraints imposed by the ongoing Covid-19 pandemic. The focus of this inspection was the Pond Water Treatment Plant (PWTP), to confirm, on a sampling basis, the licensee was implementing its compliance arrangements for LC28 (EIMT, Examination, inspection, maintenance, and testing) and LC34 (Leakage and escape of radioactive material and radioactive waste).
Interventions carried out by ONR
The compliance inspection of the PWTP was conducted against the following LCs:
- LC28: Examination, inspection, maintenance, and testing
- LC34: Leakage and escape of radioactive material and radioactive waste
The PWTP contains both radioactive material and radioactive waste. On a sampling basis I examined how the licensee implemented its arrangements to identify barriers to leakage and escape of radioactive material and radioactive waste, how it assured itself of the integrity of these barriers, and how leakage and escape would be detected. The scope of the inspection included the PWTP and the associated sludge storage tanks, and excluded the spent fuel pond. No plant walk-down of the PWTP was conducted as this inspection was undertaken remotely.
The intervention was performed in line with ONR's guidance requirements (as described in our technical inspection guides) in the areas inspected.
The scheduled closure date for Heysham 1 is in 2024; the fuel route (including the PWTP) will be required to operate for ~ five years after reactor shut down to support defuelling activities. I gathered intelligence on what activities the licensee’s was undertaking to prepare for end of generation in the context of the PWTP (and in some instances on other areas of the fuel route). This aspect of the intervention was not rated.
Explanation of judgement if safety system not judged to be adequate
This was not a system based inspection.
Key findings, inspector's opinions and reasons for judgements made
LC28: The requirements for maintenance are not derived from the PWTP safety case via appropriate safety classification schemes. However, the licensee demonstrated the PWTP is operating reliably and within required parameters; based on my LC34 focussed EIMT sample, I am satisfied the PWTP is well maintained. Taking this into account, I do not consider it proportionate to require the licensee to update the PWTP safety case to include safety classification that can be used to derive maintenance requirements. I have suggested the licensee satisfies itself EIMT not linked to LC34 requirements have been identified and are being undertaken; as I cannot confirm this based on the extant PWTP safety case. On balance, based on my sample, I judged compliance with LC28 was adequate and therefore assigned a green (no formal action) rating for LC28.
LC34: I am satisfied the licensee is adequately implementing its LC34 arrangements which require barriers to leakage and escape to be identified and their integrity assessed, based on a sample of components of the PWTP. I am satisfied means of detecting failure of these barriers are in place and in working order, based on sampling a range of inspection and maintenance records. I sampled the most recent report of the Heysham 1 ground water monitoring programme, and am satisfied any significant radioactive leak is likely to be detected. I am satisfied the licensee is identifying, reporting and repairing radioactive leaks in a timely manner, in accordance with its LC34 arrangements. Based on my sample, I judged compliance with LC34 was adequate and therefore assigned a rating of green (no formal action) for LC34 compliance.
I raised a number of observations with the licensee during the inspection, though none of these were considered to affect the ratings awarded.
Conclusion of intervention
On balance, from the sample inspected, it is judged that compliance against LC28 met the required standard; therefore a green rating was given for this licence condition. From the sample inspected, it is judged that compliance against LC34 met the required standard; therefore a green rating was given for this licence condition.
In my opinion, conducting this inspection of the PWTP remotely did not limit the scope or depth of sampling, and I was able to engage with the licensee and view evidence such as work instructions and inspection findings remotely (over Skype). The only impact was that I could not undertake a plant walk down – given much of the PWTP is not accessible because it is situated behind concrete walls to provide shielding or access is normally restricted to limit dose uptake this was not considered a significant issue.