Reactor pressure vessel toughness requirements

Fracture toughness requirements for protection against pressurized thermal shock are defined in 10 CFR Part 50,61, These requirements should be reviewed for applicability if applicable, they provide the basis for ensuring the integrity of the reactor vessel for pressurized thermal shock conditions,... 

The System 80+ reactor vessel meets the requirements of 10 CFR 50.61, "Fracture Toughness Requirements For Protection Against Pressurized Thermal Shock Events," The calculated RT is 109°F which satisfies the screening criteria in 10 CFR 50.61(d)(2). 

Fracture toughness requirements for Reactor Coolant Pressure Boundary components are established in accordance with the ASME Boiler and Pressure Vessel Code, Section III. Fracture toughness testing of base, weld and heat affected zone materials will be conducted in accordance with the ASME Code. Data from these tests will be available after the required testing has been performed and may be examined upon request at the appropriate manufacturing facility. 

A. The material used to manufacture the flywheel of the reactor coolant pump motor will be produced by a commercially acceptable process that minimizes flaws, such as the vacuum melt and degassing process. This provides adequate fracture toughness properties under reactor operating conditions. The acceptance criteria for flywheel design will be compatible with the safety philosophy of the Pressure Vessel Research Committee (PVRC) of the Welding Research Council (WRC) primary coolant pressure boundary criteria as appropriate considering the inherent design and functional requirement differences between the pressure boundary and the flywheel. 

---