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:
argest normalized residual value is equal to or less than the appropriate allowable value from the second column in Table 7. If any of these criteria is not satisfied, the licensee must propose ΔT 30 and RT MAX-X values in accordance with paragraph (f)(6)(vi) of this section. ( vi ) If any of the criteria described in paragraph (f)(6)(v) of this section are not satisfied, the licensee shall review the data base for that heat in detail, including all parameters used in Equations 5, 6, and 7 of this section and the data used to determine the baseline Charpy V-notch curve for the material in an unirradiated condition. The licensee shall submit an evaluation of the surveillance data to the NRC and shall propose ΔT 30 and RT MAX-X values, considering their plant-specific surveillance data, to be used for evaluation relative to the acceptance criteria of this rule. These evaluations must be submitted for review and approval by the Director in the form of a license amendment in accordance with the requirements of paragraphs (c)(1) and (d)(1) of this section. ( 7 ) The licensee shall report any information that significantly influences the RT MAX-X value to the Director in accordance with the requirements of paragraphs (c)(1) and (d)(1) of this section. ( g ) Equations and variables used in this section. Where: P [wt-&%] = phosphorus content Mn [wt-%] = manganese content Ni [wt-%] = nickel content Cu [wt-%] = copper content A = 1.140 × 10 −7 for forgings A = 1.561 × 10 −7 for plates A = 1.417 × 10 −7 for welds B = 102.3 for forgings B = 102.5 for plates in non-Combustion Engineering manufactured vessels B = 135.2 for plates in Combustion Engineering vessels B = 155.0 for welds φt e = φt for φ ≥4.39 × 10 10 n/cm 2 /sec φt e = φt × (4.39 × 10 10 /φ) 0.2595 for φ <4.39 × 10 10 n/cm 2 /sec Where: φ [n/cm 2 /sec] = average neutron flux t [sec] = time that the reactor has been in full power operation φt [n/cm 2 ] = φ × t f(Cu e ,P) = 0 for Cu ≤0.072