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Title: Influence of specimen size/type on the fracture toughness of five irradiated RPV materials

The Heavy-Section Steel Irradiation (HSSI) Program had previously irradiated five reactor pressure vessel (RPV) steels/welds at fast neutron fluxes of about 4 to 8 x 1011 n/cm2/s (>1 MeV) to fluences from 0.5 to 3.4 1019 n/cm2 and at 288 °C. The unirradiated fracture toughness tests were performed by Oak Ridge National Laboratory with 12.7-mm and 25.4-mm thick (0.5T and 1T) compact specimens, while the HSSI Program provided tensile and 5 x 10-mm three-point bend specimens to SCK-CEN for irradiation in the in-pile section of the Belgian Reactor BR2 at fluxes > 1013 n/cm2/s and subsequent testing by SCK-CEN. The BR2 irradiations were conducted at about 2 and 4 x 1013 n/cm2/s with irradiation temperature between 295 °C and 300 °C (water temperature), and to fluences between 6 and 10 x 1019n/cm2. The irradiation-induced shifts of the Master Curve reference temperatures, ΔT0, for most of the materials deviated from the embrittlement correlations much more than expected, motivating the testing of 5 x 10-mm three-point bend specimens of all five materials in the unirradiated condition to eliminate specimen size and geometry as a variable. Tests of the unirradiated small bend specimens resulted in Master Curve reference temperatures, T0, 25 °C tomore » 53 °C lower than those from the larger compact specimens, meaning that the irradiation-induced reference temperature shifts, ΔT0, were larger than the initial measurements, resulting in much improved agreement between the measured and predicted fracture toughness shifts.« less
 [1] ;  [2]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. National Inst. of Standards and Technology (NIST), Boulder, CO (United States)
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Resource Relation:
Conference: 17. International Conference on Environmental Degradation of Materials in Nuclear Power Systems-Water Reactors, Ottawa, ON (Canada), 10-14 Aug 2015
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
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Country of Publication:
United States
36 MATERIALS SCIENCE; SIZE; FRACTURE PROPERTIES; STEELS; FAST NEUTRONS; PHYSICAL RADIATION EFFECTS; MEV RANGE 01-10; PRESSURE VESSELS; SHAPE; TESTING; CORRELATIONS; EMBRITTLEMENT; TEMPERATURE RANGE 0400-1000 K bend; compact; dpa; fracture toughness; irradiation; Master Curve; neutron fluence; reactor pressure vessel; specimen size