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:
elds, so it may involve the entire reactor coolant system. DRAFT Rev. 2 - April 1996 5.3.2-10 The Code recommends that component hydrostatic tests be run at a temperature no lower than RT + 33 C (RT + 60 F) , but also recommends that system NDT NDT 46 tests should have more stringent requirements. The MTEBEMCB position is 47 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 RT of the vessel material must be determined. This is defined by the NDT Code for new plants, and is essentially a conservative value of the nil-ductility transition temperature (NDTT) as determined by drop weight test. Guidelines 48 for estimating the RT if the prescribed tests have not been run are given by NDT Branch Technical Position - MTEB EMCB 5-2, "Fracture Toughness 49 Requirements." Technical justification for all estimates of RT must be NDT provided by the applicant. The toughness of the material is a function of the difference between the RT of NDT the material and the temperature of interest. The Code provides a curve (Figure G-2210.1) for the allowable calculated stress intensity factor (K ) as a function IRa 50 of the temperature relative to RT . Refer to Figure 2 herein. NDT The Code also provides a recommended basis for calculating K , including I 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 K expressions I are simplified to multiples that are a function only of wall thickness and stress level. These factors, M for membrane stresses and M for bending stresses, are m B provided in graphical form in Figure G-2214.1 of the Code. Refer to Figure 1 herein. The criterion recommended by MTEB EMCB can be expressed as 51 K < K for the shell region. I IRa 52 To get K , the