Document: 10 CFR Part 50
Document ID: f3d5df11-b35b-4e81-b016-39463863b59a
Document Type: cfr
Title: Requirements for thermal annealing of the reactor pressure vessel.
Source: 10 CFR Part 50
Source URL: https://www.ecfr.gov/current/title-10/part-50/section-50.66
Revision Date: 
Chapter: 
Section ID: 50.66
CFR Part: 50
CFR Title: 10

Content:
20.1206 . ( iv ) The proposed thermal annealing operating parameters, including bounding conditions for temperatures and times, and heatup and cooldown schedules. ( A ) The thermal annealing time and temperature parameters selected must be based on projecting sufficient recovery of fracture toughness, using the procedures of paragraph (e) of this section, to satisfy the requirements of § 50.60 and § 50.61 for the proposed period of operation addressed in the application. ( B ) The time and temperature parameters evaluated as part of the thermal annealing operating plan, and supported by the evaluation results of paragraph (b)(1)(ii) of this section, represent the bounding times and temperatures for the thermal annealing operation. If these bounding conditions for times and temperatures are violated during the thermal annealing operation, then the annealing operation is considered not in accordance with the Thermal Annealing Operating Plan, as required by paragraph (c)(1) of this section, and the licensee must comply with paragraph (c)(2) of this section. ( 2 ) Requalification Inspection and Test Program. The inspection and test program to requalify the annealed reactor vessel must include the detailed monitoring, inspections, and tests proposed to demonstrate that the limitations on temperatures, times and temperature profiles, and stresses evaluated for the proposed thermal annealing conditions of paragraph (b)(1)(iv) of this section have not been exceeded, and to determine the thermal annealing time and temperature to be used in quantifying the fracture toughness recovery. The requalification inspection and test program must demonstrate that the thermal annealing operation has not degraded the reactor vessel, attached piping or appurtenances, or the adjacent concrete structures to a degree that could affect the safe operation of the reactor. ( 3 ) Fracture Toughness Recovery and Reembrittlement Trend Assurance Program. The percent recovery of RT NDT and Charpy