Office for Nuclear Regulation

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System inspection

Executive summary

Purpose of intervention

The purpose of this intervention was to carry out a planned system inspection as part of the Office for Nuclear Regulation’s (ONR’s) integrated intervention strategy for Trawsfynydd.

Interventions Carried Out by ONR

I carried out an inspection of the health physics monitoring system.  I also received updates on a number of key projects on site.

Explanation of Judgement if Safety System Not Judged to be Adequate

I consider the safety system to be adequate.

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

Overall I consider the licensee’s health physics monitoring meets and supports the requirements of its safety cases.  Against specific licence conditions (LC) I drew the following conclusions with respect to health physics monitoring:

The definition and recording of training for new starters, and the guidance for interviewing of experienced personnel, are excellent documents, and the licensee can demonstrate that they have been implemented.  The site-specific procedure for experienced staff in particular is something that I have not seen elsewhere.  As a result I consider compliance with LC 10 to be good.

Overall I consider that the licensee has an adequate process for ensuring that health physics monitoring supports the dose limits in the safety case, and that compliance with LC 23 is adequate

On the basis that the site has useable written instructions that reflect good practice, I consider compliance with LC 24 to be adequate

The site has few safety mechanisms, devices or circuits.  However, those that do exist are either in good working order, or the systems to which they relate have been suspended from service.  I therefore consider compliance with LC 27 to be adequate.

Health physics instrumentation is being adequately maintained and actively upgraded or replaced where necessary or beneficial, and on that basis I consider compliance with LC 28 to be good

As the site has both the processes and systems in place to detect the escape of radioactive material from the site, I consider compliance with LC 34 to be adequate

Conclusion of Intervention

I found no issues significantly affecting safety, or that required me to take further regulatory action.