AWE is to remain under increased scrutiny by a Government watchdog for a second year.

The Office for Nuclear Regulation, ONR, has identified AWE Aldermaston as one of just seven out of 36 UK nuclear sites which require an “enhanced level of regulatory attention.”

The report by ONR states that AWE Aldermaston is under investigation for two apparent breaches of the law – a failure to comply with instructions for radioactive waste management and for allowing “shortfalls” to arise in the operability and availability of fire detection systems at the site.

It adds that the site requires additional attention because it houses a range of ageing facilities and because of concerns about “the timeliness and quality of periodic reviews”, and that a number of safety cases for the site “do not meet expectations”.

It also highlights the additional regulatory effort needed to manage the major building programme underway at Aldermaston to enable the factory to manufacture new nuclear weapons.

However, the regulator states that it is satisfied that there are “no immediate safety concerns” at the Aldermaston site, and that the less complex AWE Burghfield site should only receive a “routine” level of regulatory attention.

AWE Aldermaston was first listed as an enforcement priority by the nuclear safety watchdog last year, following the discovery of corrosion in structural steelwork in a building which manufactures enriched uranium components for nuclear warheads and fuel for nuclear submarines.

Pete Wilkinson, director of the Reading-based Nuclear Information Service, said: “The Office for Nuclear Regulation’s report shows that, while safety standards at many nuclear sites are improving, AWE is just muddling along and marking time.”

A statement from AWE said: “Delivering safe and secure operations is a core priority for AWE and it fully supports ONR’s focus on continuous improvement, effective hazard control and maintaining high standards.”