SEDL / STP / STP1270-EB / STP16500S

Fracture Toughness Test Results of Thermal Aged Reactor Vessel Materials

DeVan, MJ
Engineer, B&W Nuclear Technologies Inc., Lynchburg, VA

Lowe, AL
Retired Advisory Engineer, B&W Nuclear Technologies Inc., Lynchburg, VA

Hall, JB
Research Engineer, Materials Performance, The Babcock & Wilcox Company, Alliance, OH

Pages: 10    Published: Jan 1996

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Abstract

Thermal-aged surveillance materials consisting of SA-533, Grade B, Class 1 plate material; SA-508, Class 2 forging material; and 2 Mn-Mo-Ni/Linde 80 weld metals were removed from two commercial reactor pressure vessels. The material from the first reactor vessel received a thermal exposure of approximately 103,000 hours at 282°C (540°F), while the material from the second reactor vessel received a thermal exposure of approximately 93,000 hours at 282°C (540°F). Tensile and 1/2T compact fracture toughness specimens were fabricated from these materials and tested. In addition, to examine the effects of annealing, selected thermal-aged and unaged specimens were annealed at 454°C (850°F) and tested. Varying responses in the fracture toughness properties were observed for all materials after exposure to the thermal-aging temperature. The base metal plate had an observed decrease in J-values after its respective aging exposure, while no significant difference in the J-values were observed for the Linde 80 weld metals. No significant difference was seen in the J-data for the aged/annealed materials, but because of the small number of test specimens available, no conclusion could be determined for the response to annealing.