A survey of defects in pressure vessels built to high standards of construction and its relevance to nuclear primary circuits

Abstract This paper surveys reported failure data on pressurised plant built to high standards of construction. The period covered is from the latter half of 1967 until the end of 1972, the information under review being limited to that gathered by the Associated Offices Technical Committee and the UKAEA Safety and Reliability Directorate. All reported events are analysed, categorised and tabulated, and a survey of British and American nuclear circuits has been made for comparison with conventional plant of relevant construction and service. Failure probabilities for the various categories of plant considered in this paper are: (i) Conventional Plant—All Types Potential Catastrophic (a) during construction 2·1 × 10 −3 — (b) during service 1·1 × 10 −3 1·5 × 10 −4 (ii) Conventional Plant Relevant To Nuclear Circuits 6·0 × 10 −4 4·7 × 10 −5 (iii) Nuclear Circuits (a) during current survey period 3·4 × 10 −2 1·15 × 10 −2 (b) considering all reactor types and including the figures from a previous survey 1·46 × 10 −2 2·5 × 10 −3