Safety Review Process for a High Consequence Operation

摘要

Nuclear warheads not only have to exhibit exceptionally high standards of safety as finished items in both normal and accident environments, but the processes by which they are assembled and disassembled also need to demonstrate commensurate levels of safety. Because AWE is now subject to regulation by the Nuclear Installations Inspectorate (NII), part of the Health and Safety Executive (HSE), such operations have to meet its criteria in order to satisfy the licence conditions for the plant. In addition, the processes are required to meet the safety standards set down by the UK's MoD. Not only are such processes unique in terms of the scale of potential consequence, but also because high explosive and radioactive materials are brought into close proximity. The safety review has to incorporate an assessment of the facility characteristics and associated infrastructure, the process and related equipment, the properties of the warhead and issues relating to human reliability. These activities require expertise from a wide range of disciplines which have to be brought together in a cohesive manner, and this represents a truly Integrated Systems Level process. The overall assessment has to identify all of the potential failures that can occur in these individual 'systems' and assess the implications for the warhead. Of course identification of the failures is but the first step in the risk analysis process which aims to demonstrate compliance with the 'regulating' and conformance criteria and to identify where effort is best directed to reduce overall risk. A major review of this nature has a timescale of about a year with associated manpower alone costs of ～￡1M.