Document: 10 CFR Part 50
Document ID: ebc72932-4988-4c38-b485-e106d10d737c
Document Type: cfr
Title: Alternate fracture toughness requirements for protection against pressurized thermal shock events.
Source: 10 CFR Part 50
Source URL: https://www.ecfr.gov/current/title-10/part-50/section-50.61a
Revision Date: 
Chapter: 
Section ID: 50.61a
CFR Part: 50
CFR Title: 10

Content:
the measured values for a weld deposit made using the same weld wire heat number as the critical vessel weld. If these values are not available, either the upper limiting values given in the material specifications to which the vessel material was fabricated, or conservative estimates ( i.e., mean plus one standard deviation) based on generic data [ 4 ] as shown in Table 4 of this section for P and Mn, must be used. ( 4 ) The values of RT NDT(U) must be evaluated according to the procedures in the ASME Code, Section III, paragraph NB-2331. If any other method is used for this evaluation, the licensee shall submit the proposed method for review and approval by the Director along with the calculation of RT MAX-X values required in paragraph (c)(1) of this section. ( i ) If a measured value of RT NDT(U) is not available, a generic mean value of RT NDT(U) for the class [ 5 ] of material must be used if there are sufficient test results to establish a mean. ( ii ) The following generic mean values of RT NDT(U) must be used unless justification for different values is provided: 0 °F for welds made with Linde 80 weld flux; and −56 °F for welds made with Linde 0091, 1092, and 124 and ARCOS B-5 weld fluxes. ( 5 ) The value of T C in Equation 6 of this section must represent the time-weighted average of the reactor cold leg temperature under normal operating full power conditions from the beginning of full power operation through the end of licensed operation. ( 6 ) The licensee shall verify that an appropriate RT MAX-X value has been calculated for each reactor vessel beltline material by considering plant-specific information that could affect the use of the model ( i.e., Equations 5, 6 and 7) of this section for the determination of a material's ΔT 30 value. ( i ) The licensee shall evaluate the results from a plant-specific or integrated surveillance program if the surveillance data satisfy the criteria described in paragraphs (f)(6)(i)(A) and (f)(6)(i)(B) of this