Safety analysis of torus vacuum breach
One of the potential safety hazards with the JET machine operating with D-T plasmas will be releases of tritiated gases following an accidental breach of the vacuum barrier. Such a situation will be contained by the JET Exhaust Detritiation System, which will maintain a sub-atmospheric pressure within the breached vacuum system and pump away and detritiate the gases prior to atmospheric discharge. This report makes a quantitative estimate of the dynamic heat and mass transfer processes involved, in order to prescribe the operating conditions of the JET Exhaust Detritiation System. The analysis considers the events following the instantaneous shattering of a 100 mm diameter vacuum window assembly. Closed solutions of the pertinent differential equations are presented both for the influx phase and the efflux phase. The analysis predicts a considerable temperature rise in the influxing air, even with no heat transfer to the air from the First Wall, which constitutes a major mitigating effect on the subsequent efflux phase. In order to reduce the probability of this type of incident, the provision of double barrier window assemblies is presently under consideration.
Bibliographic Reference: Report: JET-P(88)37 EN (1988)
Availability: Available from the Publications Officer, JET Joint Undertaking, Abingdon, Oxon. OX14 3EA (GB)
Record Number: 198910253 / Last updated on: 1994-12-01
Original language: en
Available languages: en