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:
ssion is given by K > (2)(24,000)(2.87) + 12,000 = 150,000 psi in. IRa 61 From the K curve, a temperature of RT + 158 F is required. With an IRa NDT 62 RT of 140 F (including irradiation effects), the temperature required for NDT operating pressure at a heatup or cooldown rate of 50 F/hr is then 140 + 158 = 298 F For a pressure of 1/2 of operating (1125 psig), the membrane stress is 1/2 of that at operating pressure, or 12,000 psi. The M can be taken from the 0.5 / ratio curve in Figure G-2214.1 m y (reproduced as Figure 1 herein), so is again 2.87. K (2)(12,000)(2.87) + 12,000 = 81,000 psi in. IRa 63 From the K curve, the minimum temperature is RT + 100 F, or 140 + 100 IRa NDT 64 = 240 F. The same calculation for a pressure of 1/5 operating pressure (450 psig and 4800 psi stress) is similar, but in this case the stress is less than .1 of the yield strength, so the M (from the .1 ratio curve) is only 2.82. m K (2)(4800)(2.82) + 12,000 = 39,000 psi in. IRa 65 The K curve shows that the minimum temperature is RT + 0 F, or 140 F. IRa NDT 66 Three points on a 50 F/hr operating limit curve for this vessel at this time in its service lifetime have thus been calculated: Pressure Min. Temperature (psig) (Fahrenheit) 450 140 115025 240 67 2250 298 The difference between water and metal temperatures at the 1/4T and 3/4T locations should be included in construction of the pressure-temperature limit DRAFT Rev. 2 - April 1996 5.3.2-14 curves. A smooth curve drawn through these points will very closely 68 approximate the results using more rigorous methods. d. Core Operation Appendix G, 10 CFR Part 50, specifies pressure-temperature limits for core operation to provide additional margin during actual power production. The pressure-temperature limits for core operation (except for low power physics tests) are that the reactor vessel must be at a temperature equal to or higher than the minimum temperature required for the inservice hydrostatic test, and at least 40 F higher than