Draft Guidance Regarding the Alternate Pressurized Thermal Shock Rule

The U.S. Nuclear Regulatory Commission (NRC) is issuing for public comment draft regulatory guide (DG), DG-1299, ``Regulatory Guidance on the Alternate Pressurized Thermal Shock Rule'' and accompanying draft NUREG-2163, ``Technical Basis for Regulatory Guidance on the Alternate Pressurized Thermal Shock Rule.'' The DG provides new guidance for a method that the NRC considers acceptable to permit use of the alternate fracture toughness requirements for protection against pressurized thermal shock (PTS) events for pressurized water reactor (PWR) reactor pressure vessels (RPVs). The draft NUREG provides the technical basis for DG-1299.