Document: NUREG-0800
Document ID: 866c6ef6-2f4a-45c7-9e71-43e1f66a8422
Document Type: srp
Title: Draft Revision 3– July 2018
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1807/ML18071A066.pdf
Revision Date: 2023-06
Chapter: 5
Section ID: 5
CFR Part: 
CFR Title: 

Content:
or coolant pressure boundary shall be evaluated in accordance with the requirements of Appendix G, “Fracture Toughness Criteria for Protection Against Failure,” 10 CFR Part 50, as augmented by the criteria of Section III of the ASME Code. The fracture toughness test requirements for plants with construction permits prior to August 15, 1973 may not comply with the new codes and regulations in all respects. The fracture toughness of the materials for these plants should be assessed by using the available test data to estimate the fracture toughness in the same terms as the new requirements. This approach ensures that the operating limitations imposed on old plants provide the same safety margins as are required for new plants. 1.1 Determination of RTNDT for Vessel Materials Temperature limitations are determined in relation to a characteristic temperature of the material, RTNDT, which is established from the results of fracture toughness tests. Both drop weight nil-ductility transition temperature (NDTT) tests and Charpy V-notch tests should be run to determine the RTNDT. The NDTT temperature, as determined by drop weight tests (ASTM E-208) is the RTNDT if, at 33 °C (60 °F) above the NDTT, at least 68 J (50 ft-lbs) of energy and 0.89 mm (35 mils) lateral expansion (LE) are obtained in Charpy V-notch tests on specimens oriented in the weak direction (transverse to the direction of maximum working). In most cases, the fracture toughness testing performed on vessel material for older plants did not include all tests necessary to determine the RTNDT in the manner described above. For these older plants, acceptable estimation methods for the most common cases, based on correlations of data from a large number of heats of vessel material, are provided below for guidance in determining RTNDT when measured values are not available. BTP 5-3-3 Draft Revision 3 – July 2018 (1) If drop weight tests were not performed, but full Charpy V-notch curves were obtained, the NDTT