SEDL / STP / STP426-EB / STP41326S

An Evaluation of Radiation Damage to Reactor Vessel Steels Using Both Transition Temperature and Fracture Mechanics Approaches

Landerman, E.
Pittsburgh, Pa

Yanichko, S. E.
Pittsburgh, Pa

Hazelton, W. S.
Pittsburgh, Pa

Pages: 18    Published: Jan 1967

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Abstract

As part of the Westinghouse APD irradiation effects program on structural materials, fracture toughness specimens including both Charpy V impact tests (transition temperature approach) and wedge opening loading (WOL) specimens (fracture mechanics approach) were irradiated. The reactor vessel materials investigated were two heats of SA302 Grade B including the ASTM reference correlation monitor material. The shift in the nil-ductility transition temperature (NDTT) based on Charpy impact tests and the change in fracture toughness based on WOL tests were determined. The neutron doses were 2.7 × 10¹⁰ to 1.25 × 10²⁰ n/cm² > 1 Mev at 550 F. Because of transition temperature shifts, stresses would be limited in the temperature range of 220 to 405 F during normal startup and shutdown procedures for reactor vessels. However, fracture mechanics tests showed that flaws greater than 9 in. in depth under stresses of 10,000 psi would not limit operating procedures at temperatures above 300 F.