Properties of an irradiated heat-treated Zr-2.5Nb pressure tube removed from the NPD reactor
- AECL, Pinawa, Manitoba (Canada). Whiteshell Labs.
- AECL, Chalk River, Ontario (Canada). Chalk River Labs.
- Power Reactor and Nuclear Fuel Development Corp., Higashi, Ibaraki (Japan). O-Arai Engineering Centre
Some pressure tubes in reactors moderated by heavy water have been made from heat-treated (HT) Zr-2.5Nb. One such tube was removed from the NPD nuclear reactor after 20 years of operation. An extensive program was carried out jointly by AECL and PNC to evaluate the condition and properties of this pressure tube. The investigations include irradiation creep, tensile, corrosion, delayed hydride cracking (DHC), fatigue, and fracture properties. Results show that: (1) the in-reactor elongation rate is much lower and the transverse strain rates are slightly larger than in cold-worked (CW) Zr-2.5Nb tubes: (2) the tensile properties, hydrogen pickup, threshold stress intensity factor for DHC initiation, DHC velocity, and fatigue crack growth rates were similar to those of the CW Zr-2.54Nb material; (3) the fracture toughness of this tube, as measured by curved compact toughness specimens and burst tests, is slightly higher than the CW tubes. The results were also compared with other heat-treated Zr-2.5Nb materials irradiated in the Fugen reactor. The tube was in excellent condition when removed from the reactor and would have been satisfactory for further service.
- Sponsoring Organization:
- Organization of CANDU Industries, Toronto, ON (Canada)
- OSTI ID:
- 479449
- Report Number(s):
- CONF-950926--
- Country of Publication:
- United States
- Language:
- English
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