Document: NUREG-0800
Document ID: 685c3a08-2aef-45d3-adfa-5101ca619cd1
Document Type: srp
Title: Revision 2 - March 2007
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0708/ML070850035.pdf
Revision Date: 2023-06
Chapter: 5
Section ID: 5
CFR Part: 
CFR Title: 

Content:
4. Pressurized Thermal Shock (PWR only) 4.1 Pressurized Thermal Shock Requirements As required by 10 CFR 50.61, the following is a summary of requirements for the PWR reactor vessels: (1) RTPTS values must be projected using end-of-life fluence for each weld, plate or forging in the reactor vessel beltline region. The projected EOL RTPTS values must be approved by the NRC. (2) PTS screening criteria is 132 EC (270 EF) for plates, forgings, and axial weld materials, and 149 EC (300 EF) for circumferential weld materials. (3) If reactor vessel is projected to exceed the PTS screening criteria, 10 CFR 50.61(b)(3) requires the applicant to implement a flux reduction program that is reasonably practicable to avoid exceeding the PTS screening criteria. (4) If the flux reduction program does not prevent the reactor vessel from exceeding the PTS screening criterion at the end of life, the applicant choose between the two options in 10 CFR 50.61 to meet PTS requirements: (a) submit a safety analysis pursuant to 10 CFR 50.61(b)(4) to determine what, if, any, modifications to equipment, systems, and plant operation to prevent failure of the reactor vessel from a postulated PTS event, (b) perform a thermal-annealing BTP 5-3-8 Revision 2 - March 2007 treatment of the reactor vessel pursuant 10 CFR 50.61(b)(7) to recover fracture toughness. 10 CFR 50.61 requires details of the approach selected to be submitted for NRC approval at least 3 years before the reactor vessel is projected to exceed the PTS screening criteria. C. REFERENCES 1. 10 CFR Part 50, Appendix A, “General Design Criteria for Nuclear Power Plants.” 2. 10 CFR Part 50, Appendix G, “Fracture Toughness Requirements.” 3. 10 CFR Part 50, Appendix H, “Reactor Vessel Material Surveillance Program Requirements.” 4. 10 CFR 50.61, “Fracture Toughness Requirements for Protection Against Pressurized Thermal Shock Events.” 5. NUREG-0744, “Pressure Vessel Material Fracture Toughness.” 6. ASME Boiler and