8. Nuclear Components Operating in the Creep Regime

Construction rules for high temperature reactors (HTRs) are published in ASME III-5, addressing both high temperature gas-cooled reactors (HTGRs) and high temperature liquid-cooled reactors (HTLRs). The rules address both low temperature operating conditions, typically 700°F (370°C) or less, for carbon and martensitic steels and 800°F (425°C) or less for austenitic or high nickel alloys as well as elevated temperatures conditions and both metallic and nonmetallic materials. Effective from the 2015 Edition, the ASME III-NH was discontinued and the subject matter transferred to ASME III-5, Subsection HB.