The Radiation Surveillance Program for Combustion Engineering (C-E) Reactor Vessel Materials is designed to provide the operating utility with the capability of determining the radiation-induced changes in the mechanical and fracture toughness properties of the materials in the region of the reactor vessel encompassing the core. The term “materials” is used to collectively describe the metallurgical characteristics of base metal, deposited weld metal, and the heat-affected-zone (HAZ) metal. By conducting such determinations periodically, the neutron-induced changes in the initial reference temperature (RT^NDT) can be assessed by direct measurement and the conservatism in the planned adjustments to plant operating parameters to compensate for the RT^NDT changes can be verified.