This volume brings together the papers presented at the 7th Symposium organised by the Technical Advisory Group on Structural Integrity of Nuclear Plant (TAGS!) which was held at the TWI Conference Centre, Great Abington, UK on 29 April 1999. The Symposium, which marked 25 years of TAGSI and its predecessor, the Light Water Reactor Study Group (LWRSG), was dedicated to Sir Alan Cottrell FREng, FRS, whose impact on the fields of integrity, reliability and safety of engineering structures and components has been second to none.