There are now many nuclear power plants operating which are at least 30 years old and many are approaching the end of their original design life. Central to the continued safe operation of these plants is the structural integrity of various safety critical components.

One such is the concrete pressure vessel. These vessels have to withstand large internal pressures (~ 4 MPa at 700°C in the case of an UK AGR). During lifetime, the pressure vessels deform and age.

The MAECENA project (Crouch et al., to be published) has the objective of investigating an important area of concrete behaviour that influences the ageing process, i. e. the softening and weakening of the effects of thermal and pressure cycling, and progressive creep and relaxation. The programme involves laboratory-based experimental work together with the development of finite element code methodology.

Concrete containment behaviour under various loading conditions has been considered in the European Commission CONMOD programme (Jovall et al., to be published). This aims to create a system for the assessment of containments throughout their lifetime. An important aspect is to develop NDT techniques and integrate these with finite element modelling techniques.