Document: NUREG-0800
Document ID: c9c204f0-a162-491c-8c25-ee0418212f29
Document Type: srp
Title: PRESSURE-TEMPERATURE LIMITS, UPPER-SHELF ENERGY, AND PRESSURIZED
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0703/ML070380185.pdf
Revision Date: 2023-06
Chapter: 5
Section ID: 5.3.2
CFR Part: 
CFR Title: 

Content:
g Figure 1 is the metal temperature at the tip of the postulated flaw from Appendix G to Section XI of the ASME Code (i.e., at either the 1/4 T or 3/4 T location). The metal temperature at throughwall locations will depend on the reactor coolant system fluid temperature and the rate of change of the reactor coolant system fluid temperature. Throughwall metal temperatures can be determined from methods given in Appendix G to Section XI of the ASME Code or from ORNL/NRC/LTR- 03/03. vi. Based on the discussion above, it is recommended that the following equation be solved to determine the allowable pressure associated with a specified temperature along a P-T limit curve: allowable pressure = t * (KIc - KI thermal) / (SF * Mm * Ri) which is an algebraic rearrangement of the equation from (iv). The reviewer should keep in mind, however, that four of the quantities (KIc, KI thermal, SF, and Mm) are dependent on other, more basic variables or conditions: KIc—Depends on metal temperature and material RTNDT KI thermal—Depends on heatup/cooldown rate and vessel wall thickness SF—Depends on the curve being evaluated and the assumed flaw orientation 5.3.2-12 Revision 2 - March 2007 Mm—Depends on the vessel wall thickness and the assumed flaw orientation vii. The reviewer should verify that all minimum temperature requirements specified in Appendix G to 10 CFR Part 50 for the P-T limit curve being verified have been met. These requirements have been imposed to ensure that highly stressed, nonbeltline regions (i.e., the vessel flange region) are protected from brittle failure. viii. It should also be noted that some applications may provide P-T limit curves for other specific nonbeltline regions (e.g., the nozzle course and/or the bottom head of a boiling-water reactor) to address specific modes of operation. These nonbeltline curves are normally submitted to provide additional operational/testing flexibility and are generally less restrictive than the corresponding