Office for Nuclear Regulation

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Mensa LC26 Compliance Inspection + Gen Interventions

Executive summary

Purpose of intervention

This report covers planned interventions carried out as part of the regulation of the Atomic Weapons Establishment. Planned Compliance Inspections form part of the identified intervention programmes of work specified in the Integrated Intervention Strategy and Major Projects Intervention Plan for the ONR Weapons Sub-Programme.

Interventions Carried Out by ONR

I attended AWE’s Burghfield sites to undertake a Compliance Inspection on the Mensa project in relation to Licence Condition (LC) 26 (control & supervision of operations). Also reported here is a meeting to review the AWE arrangements under LC22 (modification or experiment on existing plant) and other technical interventions carried out during the monthly programmed Inspection Week for September.

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

Explanation of Judgement if Safety System Not Judged to be Adequate


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

Mensa Compliance Inspection on Licence Condition 26: Rated as Below Standard. Mensa has a good safety record that demonstrates good control over conventional safety during construction. However, control over nuclear safety matters needs to be demonstrated, especially as the project moves forward from construction.

ONR and AWE discussed development of AWE’s Arrangements under LC22 with the intent of enabling Flexible Permissioning. ONR made a number of observations regarding these Arrangements that have been recorded by AWE for consideration during this development. Of note is the need to address the requirements of LC20 (Modification to design of plant under construction) during modifications initiated under LC22.

Conclusion of Intervention

It is my opinion that the Mensa Project demonstrates LC26 controls from a Nuclear Safety perspective as the project moves forward from construction.

In the context of enabling flexible regulatory permissioning, it is my opinion that AWE should clarify Arrangements to handle the requirements of LC20 during modifications initiated under LC22.