Repairs to structural damage to a major nuclear processing facility at Britain's main nuclear weapons factory will not be completed until May 2015 – almost three years after the problems were first discovered.
The Office for Nuclear Regulation (ONR) has extended a deadline for completing repairs to the A45 nuclear processing building at the Atomic Weapons Establishment (AWE) Aldermaston from the end of December 2013 to the end of May 2015.
The A45 building, which makes enriched uranium components for nuclear warheads and fuel for nuclear submarines, was closed in August 2012 following the discovery of corrosion in structural steelwork. In November ONR issued a formal improvement notice requiring AWE to conduct repairs to bring the structure to an acceptable standard by 31 December 2013.
The improvement notice required AWE to complete a structural inspection of the building, repair it to the required standard, carry out a review to identify lessons learnt from the affair, and carry out a review of the Plant Maintenance Schedule for the building.
AWE advised ONR that the inspection and review work would be complete by the end of 2013 but requested an extension to the deadline for completing repair work, arguing that the timescale needed to undertake the work was longer than anticipated when the improvement notice was issued because of the complex nature of the building and the controls that have to be in place for the conduct of repair work.
ONR has agreed to extend the deadline for full completion of repair work until 31 May 2015, accepting that AWE has put in place a full plan in place for the necessary repairs and has reduced the potential hazard in the affected area of the building by significantly reducing the inventory of radioactive material.
The A45 corrosion problems were assessed as having “major” significance by AWE staff and were rated as the most serious safety problem at any UK nuclear site in the last three years by the Office for Nuclear Regulation in its annual report for 2013.
Following an investigation into the problems ONR concluded that although AWE had not acted recklessly or ignored safety standards, “people were exposed to risk by AWE’s failure to adequately maintain the class 1 structure”. The investigation found “clear evidence” that AWE had failed to comply with the conditions of its nuclear site operating licence because arrangements for the inspection and maintenance of a nuclear structure were not adequate to prevent its degradation, resulting in risks to nuclear safety