Office for Nuclear Regulation

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HSE decision on the adequacy of the Periodic Safety Review for continued operation of Dungeness B

HSE's NII has now completed its independent assessment of the second Dungeness B Periodic Safety Review undertaken by the nuclear site licensee, British Energy Generation Limited (BE).

After careful consideration NII has concluded there is an appropriate basis for station operation whilst a PSR derived programme of work is progressed. NII has given the decision in a letter to the station director.

NII will produce a project overview report explaining the decision and the programme of work in greater detail. A link to it will be provided from this page when the report is issued.

Background

Periodic Safety Reviews (PSR) are required by the Site Licence to provide a systematic review and reassessment of the safety case, looking forwards up to ten years. NII require UK reactor licensees to carry out a PSR every ten years for each nuclear reactor site, in line with international best practice. These are significant undertakings for the licensee, and the review process may extend over a period of around 3 years.

The purpose of a PSR is to ensure that a thorough, comprehensive review is made of the basis for continued long term safe operation at regular intervals throughout a nuclear power station's life. In carrying out the review, the licensee is expected to review the total current safety case for the station and confirm its continued adequacy; to compare against current standards for new plant, evaluate any shortcomings and implement any reasonably practicable improvements to enhance plant safety; to identify any ageing process which may limit the safe life of the plant; and where necessary to revalidate the safety case until the next PSR, subject to the outcome of routine regulation.

There are always some items where uncertainty over ageing mechanisms may mean that a full case for the next ten years cannot be made. In these cases, PSR acceptance is caveated to recognise this. For AGRs, this uncertainty is, in particular, in areas of graphite integrity and in the ageing of certain structural features (e.g. the current issues with the boiler closure units at the Heysham 1 and Hartlepool ). The approach is that these items are subject to more frequent inspection and forward predictions. Return from periodic shutdown for routine inspection and maintenance is only for periods of operation for which there is adequate certainty in the performance of these components. Performing an adequate periodic review is therefore a necessary basis for ten years of future operation, continued maintenance, inspection and testing will also be required to justify continued operation. Further interactions occur as part of the permissioning process following each planned periodic shutdown. Additionally NII has powers to direct reactor shutdown at any time, should new information become available which affects the confidence in the safety operation of the plant.

NIIhas produced a project overview report explaining the decision and the programme of work in greater detail.