Document: NUREG-0800
Document ID: 26aca061-b0de-4983-bbca-3fccb00afc2f
Document Type: srp
Title: PRESSURE-TEMPERATURE LIMITS AND PRESSURIZED THERMAL SHOCK1
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070431.pdf
Revision Date: 2023-06
Chapter: 5
Section ID: 5.3.2
CFR Part: 
CFR Title: 

Content:
Basis Documents 10 CFR 50.60, and associated Appendices G and H of 10 CFR Part 50, describe the 14 15 conditions that require pressure-temperature limits and provide the general basis for these DRAFT Rev. 2 - April 1996 5.3.2-4 limits. These appendices specifically require that pressure-temperature limits must provide safety margins at least as great as those recommended in the ASME Boiler and Pressure Vessel Code (hereinafter "the Code"), Section III, Appendix G, "Protection Against Nonductile Failure," (Reference 14) during heatup, cooldown, and test 16 conditions. Appendix G to 10 CFR Part 50 also requires additional safety margins whenever the reactor core is critical (except for low-level physics tests). In addition to the pressure-temperature limits established in accordance with 10 CFR 50.60, and Appendix G, projected values of RT must be determined for PWR reactor PTS vessel beltline materials in accordance with 10 CFR 50.61. These values of RT must PTS meet the temperature limit screening criteria in the rule, or must be accompanied by safety analyses developed in accordance with 10 CFR 50.61 and the guidance of Regulatory Guide 1.154.17 2. Technical Bases Since many of the fracture toughness requirements for the ferritic materials in the pressure-retaining components were not required at the time some of the reactor facilities were designed and constructed, the Materials Engineering BranchMaterials and Chemical Engineering Branch Technical Position MTEB EMCB 5-2, "Fracture Toughness 18 Requirements," describe procedures for making estimates and assumptions on the fracture toughness properties of materials in the older plants. Calculations are required, and an evaluation is made by the reviewer to show compliance with the regulations and to show an adequate margin of quality and safety for the facility. When it has been determined that certain requirements of Appendices G or H have not been strictly complied with by these older plants, and when it has been