Reactor pressure vessel RPV materials selection

RPV shell plate material specifications have evolved since the beginning of the commercial nuclear power industry in the mid-1950s. Due to safety concerns for nuclear RPVs, cautious steel-making was paramount, as well as careful RPV fabrication and welding practices. Nevertheless, the need for familiarity in steel-making and fabrication processes initially led to the selection and use of old steels typical of prior (non-nuclear) pressure vessel service. Table 1.1 lists the principal steel plate materials used in construction of nuclear RPV components. All of the plate materials used 

Grade Heat treatment Vessels Usage Type 

Many of the early designed RPVs were made from carbon mild steels, usually in the normalized and tempered condition. The A212 plate material was only used in very early nuclear plants, which are now decommissioned. A more widely used material, SA-302, Grade B, is a Mn-Mo steel for plate materials. This type of steel was used in the quenched and tempered condition for a number of RPVs fabricated through the mid-1960s. 

The RPV forging materials shown in Table 1.2 have also evolved since the mid-1950s. The earliest grade, A105 Class 2, was used in the normalized and tempered condition for flanges and nozzles. This simple C-Mn steel was used to a very limited extent in RPVs that are now decommissioned. A 

Grade Heat treatment Applications Usage Type 

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