A UK regulatory perspective of criticality safety. Past, present and future

This paper reflects on past experiences in the development of the UK nuclear industry from a criticality safety perspective and identifies some key aspects which have helped to influence current UK industry practices and regulatory thinking. It will then identify a number of activities which contribute effectively to maintaining current high standards of criticality safety and awareness and then propose a number of areas which may be of importance to criticality practitioners and regulators in the future. The Health and Safety Executive (HSE) is the lead UK regulatory agency responsible for the enforcement of health and safety legislation at nuclear sites in the UK. This includes inspection and assessment of safety arrangements and for controlling risks from criticality in nuclear plant. Regulation of nuclear safety in the UK is largely based upon a permissioning licensing system combined with an overriding requirement to reduce risks to workers and the public to a level which is as low as reasonably practicable. The licensing system permits a flexible approach to criticality safety enabling the operator or licensee to develop safety cases suited to local plant conditions. The responsibility for safety rests firmly with the operator and as regulators HSE needs to be satisfied on the adequacy of arrangements which are in place to ensure safety. In order to assist nuclear inspectors in forming a view on adequacy HSE has developed and published it Safety Assessment Principles which describe goal setting standards for the design and operation of nuclear plant including aspects relating to criticality safety. (author)