Regulatory Guidance and Technical Basis on the Alternate Pressurized Thermal Shock Rule

The U.S. Nuclear Regulatory Commission (NRC) is issuing Revision 0 to Regulatory Guide (RG) 1.230, ``Regulatory Guidance on the Alternate Pressurized Thermal Shock Rule'' and the associated technical basis, NUREG-2163, ``Technical Basis for Regulatory Guidance on the Alternate Pressurized Thermal Shock Rule.'' This guidance describes a method that the NRC staff considers acceptable to permit use of the alternate fracture toughness requirements for protection against pressurized thermal shock events for pressurized water reactor pressure vessels.