Probabilistic Consequence Assessment of Hydrogen Sulphide Releases from a Heavy Water Plant. Scope Determination

摘要

This report is concerned with the evaluation of the consequences to the public of an accidental release of hydrogen sulphide (H sub 2 S) to the atmosphere following a pipe or pressure envelope failure, or some other process upset, at a heavy water plant. It covers the first stage of a programme in which the nature of the problem was analyzed and recommendations made for the implementation of a computer model. The concepts of risk assessment and consequence assessment are discussed and a methodology proposed for combining the various elements of the problem into an overall consequence model. These elements are identified as the 'Initiating Events', 'Route to Receptor' and 'Receptor Response' and each is studied in detail in the report. Such phenomena as the blowdown of H sub 2 S from a rupture, the initial gas cloud behaviour, atmospheric dispersion and the toxicity of H sub 2 S and sulphur dioxide (SO sub 2 ) are addressed. Critical factors are identified and modelling requirements specified, with special reference to the Bruce heavy water plant. Finally, an overall model is recommended for implementation at the next stage of the programme, together with detailed terms of reference for the remaining work. (Atomindex citation 16:042207)