Change of mechanical properties by irradiation and evaluation of the heat-treated Zr-2.5Nb pressure tube
- Power Reactor and Nuclear Fuel Development Corp., Ibaraki (Japan). Oarai Engineering Center
- Power Reactor and Nuclear Fuel Development Corp., Fukui (Japan). Fugen Nuclear Power Station
The prototype advanced thermal reactor, Fugen (165MWe), is a heavy-water-moderated, boiling-light-water-cooled, pressure tube type reactor. A Zr-2.5 Nb alloy, in the heat-treated condition to improve its high-temperature strength, is used for the pressure tubes in the Fugen. Pressure tube surveillance specimens were assembled in the inside of the special fuel assemblies from the initial stage of the operation and were exposed to irradiation. The post-irradiation examinations of the first and second surveillance specimens were performed. The tensile strength increased by 30% when fast neutron fluence was >2 {times} 10{sup 25} n/m{sup 2}. The decreasing rate of the fracture toughness was large over the initial period of the irradiation and became smaller when fast neutron fluence was >2 {times} 10{sup 25} n/m{sup 2}. The corrosion rate was measured as {minus}1 {mu}m/year and the hydrogen pickup rate was measured as 1 ppm/year. Based on the results, a predictive capability for each respective property for 30 years was established, which demonstrated the integrity of the pressure tube for 30 years.
- OSTI ID:
- 55653
- Report Number(s):
- CONF-930611--; ISBN 0-8031-2011-7
- Country of Publication:
- United States
- Language:
- English
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