A review of materials and fabrication methods used in light water reactor pressure vessels

The success of current industry efforts to extend the service life of nuclear power plants depends critically on the long-term integrity of reactor pressure vessels. This paper describes the materials and fabrication methods of reactor pressure vessels now in service, as an introduction to a more in-depth review of the underlying basis for continued serviceability of this key component. Materials selection and specifications have been altered several times since the first commercial plants were built, in response to demands for improved mechanical properties, for elimination of certain fabrication problems, and for resistance to radiation embrittlement. Other considerations have influenced the choice of welding and weld cladding procedures. All of the reactor pressure vessels in domestic service have performed very well. Projections of long-term performance and potential degradation depend in part on material and fabrication variables discussed herein