To ask the Secretary of State for Defence

(1) on what dates (a) his Department, (b) the Office for Nuclear Regulation and (c) the Defence Nuclear Safety Regulator were notified by Atomic Weapons Establishment Aldermaston about problems with the structural condition of building A45 at Atomic Weapons Establishment Aldermaston;

(2) how many buildings at Atomic Weapons Establishment Aldermaston are affected by degradation of steelwork in building structures; in which building production operations have been halted; what assessment he has made of the potential effect on the delivery of the Astute class submarine programme; and if he will make a statement;

(3) what his target date is for completion of work to remedy structural problems identified in steelwork in buildings at Atomic Weapons Establishment Aldermaston; what is the expected cost of remedying those problems; whether the costs of this work will be paid out of the budgeted costs of the management and operation contract for the Atomic Weapons Establishment between his Department and AWE Management Ltd or by other means; and if he will make a statement.

An inspection conducted on 21 August 2012, as part of the regular maintenance process, found signs of corrosion in a steel column in the uranium handling facility located on the Atomic Weapons Establishment's (AWE) Aldermaston site. Routine operations were suspended as a precaution.

AWE informed the Office of Nuclear Regulation (ONR) on 23 August 2012 and the Ministry of Defence on 30 August 2012. The Defence Nuclear Safety Regulator was subsequently informed by ONR in accordance with extant regulatory arrangements. The ONR issued an Improvement Notice on this facility on 7 November 2012.

An enhanced site-wide survey has revealed some corrosion at two other buildings of similar construction; however, these buildings do not undertake any nuclear operations. Production operations have been halted in the uranium handling facility only. There has been no impact on any of our submarine programmes.

In conjunction with the ONR, work is ongoing to identify the optimum method of remediation, which will enable the ONR's target date for implementation of AWE's improvements by December 2013 to be met. It is too early to estimate the costs involved, or to say whether they will be met within the budgeted cost of the management and operation contract.