Document: NUREG-0800
Document ID: e2737d9a-8e56-46cb-a97d-aaf62a442c6c
Document Type: srp
Title: PRESSURE-TEMPERATURE LIMITS
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052340637.pdf
Revision Date: 2023-06
Chapter: 5
Section ID: 5.3.2
CFR Part: 
CFR Title: 

Content:
low, and the curves necessary to perform the calculations are included herein as Figures 1, 2 and 3. a. Preservice Hydrostatic Tests The preservice hydrotest at 1.25 design pressure corresponds to the standard Code component hydrotest usually performed in the shop, but in this case it is the hydrotest for field welds, so it may involve the entire reactor coolant system. The Code recommends that component hydrostatic tests be run at a temperature no lower than RTNDT + 600F, but also recommends that system tests should have more stringent requirements. The MTEB position is that the minimum temperature for the preservice test, if fuel is not in the vessel, be determined using the methods of Code Section III, Appendix G, using less stringent factors. First, the RTNDT of the vessel material must be determined. This is defined by the Code for new plants, and is essentially a conservative value of the NDTT as determined by drop weight test. Guidelines for estimating the RTNDT if the prescribed tests have not been run are given by Branch Technical Position - MTEB 5-2, "Fracture Toughness Requirements." Technical justification for all estimates of RTNDT must be provided by the applicant. 5.3.2-5 Rev. 1 - July 1981 The toughness of the material is a function of the difference between the RTNDT of the material and the temperature of interest. The Code provides a curve (Figure G-2210.1) for the allowable calculated stress intensity factor (KIR) as a function of the temperature relative to RTNDT. Refer to Figure 2 herein. The Code also provides a recommended basis for calculating KI, including recommendations for assumed flaw size and shape, and appropriate front and back surface correction factors. Because the assumed flaw size is proportional to the wall thickness, t (flaw depth = 0.25 t and length = 1.5 t), the KI expressions are simpli- fied to multiples that are a function only of wall thickness and stress level. These factors, Mm for membrane stresses and M. for bending