The leak in super heater 2

An under sodium leak occurred in Superheater 2 on PFR on 27 February 1987 when the plant was operating on full power. No warning was received by the operators prior to failure of the superheater bursting disc and automatic shut down of the plant. Subsequent examination has shown that 40 tubes suffered damage each equivalent to double ended guillotine failure, with evidence of some damage on a further 70 tubes. This paper reviews the cause of the initial failure and suggests mechanisms which caused further damage