AGR boiler materials selection considerations

Initial materials selection for the AGR once-through boilers was uniquely influenced by corrosion considerations of both primary and secondary coolants. Prior to boiler start-up and as additional longer term corrosion data became available, a number of detailed optimisations of local environmental conditions were necessary to meet the 250 x 103 hr design life requirement. An overview of factors influencing initial materials selection and the more significant of the subsequent optimisations in the several zones of the boiler are discussed. (author)