Office for Nuclear Regulation

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Basis for ONR decision on the Periodic Review of Aldermaston Site

Permission requested

In accordance with its arrangements for complying with Licence Condition 15, AWE submitted a Periodic Review of Safety (PRS) for the Aldermaston nuclear licensed site (The Aldermaston Site Wide PRS) site to ONR on 29 July 2010.


This was the first Aldermaston site wide PRS to be submitted to ONR by AWE since the site was licensed under the Nuclear Installations Act, in July 1997.

Assessment and inspection work carried out by Office for Nuclear Regulation (ONR) in consideration of this request

ONR inspectors made a detailed assessment of AWE's submission against HSE Safety Assessment Principles (SAPs) and Technical Assessment Guidance (TAGs).

Although AWE's initial PRS submission did not meet ONR's expectations in a number of areas, ONR inspectors considered AWE's final submission adequate, and were content that identified safety improvements would be implemented within a reasonable timescale. In making a decision, ONR inspectors considered the age of certain facilities in relation to their remaining operational life, and the ongoing programme of work to replace some site facilities.

Matters arising from ONR's work

ONR's assessment found deficiencies in AWE's demonstration that some site support systems would remain adequate to deliver their safety functions throughout the period covered by the PRS. Some aspects of AWE's comparison between existing site systems and the requirements of modern standards fell short of regulatory expectations.

AWE provided ONR with additional information to support the PRS conclusion.


I am content with the conclusion of the Aldermaston Site Wide Periodic Review of Safety, that the site is safe for operations.

I consider that, subject to adequate progress against the Aldermaston Site Wide Periodic Review of Safety forward programme of work, and satisfactory results from the Licensees ongoing programme of monitoring and assurance, the site will remain safe until submission of the next Site Wide PRS in 2019.

Progress against the forward programme of work will be regularly monitored by ONR.


I recommend acceptance of the conclusion of the Aldermaston Site Wide Periodic Review of Safety that the site remains safe for continued operations.