Investigation into the Consequences of the Failure of a Turbine-Generator at Hinkley Point ‘A’ Power Station

Abstract

The further investigation was extensive and is continuing but the present account is limited to what throws light on the Hinkley Point ‘A’ incident and its immediate consequences. There were three main areas of investigation: (1) laboratory and on-site exploration of conditions for stress corrosion cracking of relevant steels; (2) a survey of all relevant rotors to explore the effects of applying a purely fracture mechanics approach in ignorance of the mechanism causing the initial crack or defect; (3) an examination of rotors withdrawn from machines of similar mechanical design and of properties deemed to be in the highest risk category. Interim conclusions have been drawn. They suggest that in certain non-reheat turbines it is possible to generate high chemical concentrations in regions of high stress and thus to promote stress corrosion cracking. The rate of propagation of such cracks is sufficient to produce critical stress intensities in discs of low fracture toughness in a region of high stress concentration.