Tube-Burst Response of Irradiated Zircaloy Spent-Fuel Cladding

Abstract

Transient-heating tube-burst tests were conducted on a 50.8-cm length of Zircaloy cladding obtained from spent-fuel rods irradiated in the H. B. Robinson power reactor to a peak burn-up of 30 MWD/kg. Internal electrical resistance heaters were used to achieve nominal heating rates of 28°C/s for the tests. The tests were conducted in steam and the independent experimental variable was the initial level of helium pressurization. Tube burst pressures varied from 0.965 to 12.514 MPa. Corresponding burst stresses and temperatures varied from 7.5 MPa and 1135°C to 99.1 MPa and 734°C, respectively. Failure strains ranged up to 46 percent when burst occurred at upper (α + β) and β-phase temperatures and up to 30 percent for failures occurring at lower temperatures. No significant difference in burst behavior between unirradiated and spent nuclear fuel Zircaloy cladding was observed experimentally. No influence of axial restraint on burst strains was noted.

In-situ tube burst testing and high-temperature deformation behavior of candidate materials for accident tolerant fuel cladding

“…The traditional tube burst testing to measure rupture stress and temperature is a wellestablished method that has helped accumulate a sizable database for fuel cladding materials [7][8][9][10][11][12][13][14]29]. In Figure 11 the rupture (burst) temperature versus hoop stress data for new alloys are compared to the database for Zircaloy-4, which is a collection of cladding rupture data for a variety of materials and pressurization conditions [29].…”

“…Traditionally, tube burst testing using high-pressure gas has been performed to measure the burst temperature as a function of internal pressure and to assess the performance of new and irradiated cladding specimens [7][8][9][10][11][12][13][14]. Typically a ~30 cm (1 foot) long tubular specimen is employed in such tube burst testing [14].…”