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:
are expected to experience significant thermal or stress effects during the thermal annealing operation; ( ii ) An evaluation of the effects of mechanical and thermal stresses and temperatures on the vessel, containment, biological shield, attached piping and appurtenances, and adjacent equipment and components to demonstrate that operability of the reactor will not be detrimentally affected. This evaluation must include: ( A ) Detailed thermal and structural analyses to establish the time and temperature profile of the annealing operation. These analyses must include heatup and cooldown rates, and must demonstrate that localized temperatures, thermal stress gradients, and subsequent residual stresses will not result in unacceptable dimensional changes or distortions in the vessel, attached piping and appurtenances, and that the thermal annealing cycle will not result in unacceptable degradation of the fatigue life of these components. ( B ) The effects of localized high temperatures on degradation of the concrete adjacent to the vessel and changes in thermal and mechanical properties, if any, of the reactor vessel insulation, and on detrimental effects, if any, on containment and the biological shield. If the design temperature limitations for the adjacent concrete structure are to be exceeded during the thermal annealing operation, an acceptable maximum temperature for the concrete must be established for the annealing operation using appropriate test data. ( iii ) The methods, including heat source, instrumentation and procedures proposed for performing the thermal annealing. This shall include any special precautions necessary to minimize occupational exposure, in accordance with the As Low As Reasonably Achievable (ALARA) principle and the provisions of § 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