Document: NRC Regulatory Guide
Document ID: 5f4d6577-6c2a-473a-9a76-4033a95dba4c
Document Type: regulatory_guide
Title: Radiation Embrittlement of Reactor Vessel Materials (Rev. 2)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0037/ML003740284.pdf
Revision Date: 2023-05
Chapter: 
Section ID: RG-1.99
CFR Part: 
CFR Title: 

Content:
agraph V .A of Appendix G requires the effects of neutron radiation to be predicted from the results of pertinent radiation effects studies. This guide provides such results in the form of calculative procedures that are acceptable. to the ·NRc. 2. Paragraph V .B of Appendix G describes the basis for setting the upper limit for pressure as a function of temperature during heatup and cooldown for a given service period in terms of the predicted value of the adjusted reference temperature at the end of the service period. 3. The definition of reactor vessel beltline given in Paragraph II. F of Appendix G requires identification of regions of the reactor vessel that are predicted to experience sufficient neutron radiation embrittlement to be considered in the selection of the most limiting material. Paragraphs ill.A and N.A.1 specify the additional test requirements for beltline materials that supplement the requirements for reactor vessel materials generally. 4. Paragraph 11.B of Appendix H incorporates ASTM E 185 by reference. Paragraph 5.1 of ASTM E 185-82, "Standard Prac- tice for Conducting Surveillance Tests for Light-Water Cooled Nuclear Power Reactor Vessels'' (Ref. 1), requires that the materials to be placed in surveillance be those that may limit operation of the reactor during its lifetime, i.e., those expected to have the highest adjusted reference temperature or the lowest Charpy upper-shelf energy at end of life. Both measures of radiation embrittlement must be considered. In Paragraph 7.6 of ASTM E 185-82, the require- ments for the number of capsules and the withdrawal schedule are based on the calculated amount of radiation embrittlement at end of life. The guides are issued in the following ten broad divisions: 1. Power Reactors 6. Products 2. Research and Test Reactors 7. Transportation 3. Fuels and Materials Facllltles 8. Occupational Health 4. Environmental and Siting 9. Antitrust and Financial Review 5. Materials and Plant Protection 10. General