ORNL Interim Progress Report on Hydride Reorientation CIRFT Tests
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
A systematic study of H. B. Robinson (HBR) high burnup spent nuclear fuel (SNF) vibration integrity was performed in Phase I project under simulated transportation environments, using the Cyclic Integrated Reversible-Bending Fatigue Tester (CIRFT) hot cell testing technology developed at Oak Ridge National Laboratory in 2013–14. The data analysis on the as-irradiated HBR SNF rods demonstrated that the load amplitude is the dominant factor that controls the fatigue life of bending rods. However, previous studies have shown that the hydrogen content and hydride morphology has an important effect on zirconium alloy mechanical properties. To address the effect of radial hydrides in SNF rods, in Phase II a test procedure was developed to simulate the effects of elevated temperatures, pressures, and stresses during transfer-drying operations. Pressurized and sealed fuel segments were heated to the target temperature for a preset hold time and slow-cooled at a controlled rate. The procedure was applied to both non-irradiated/prehydrided and high-burnup Zircaloy-4 fueled cladding segments using the Nuclear Regulatory Commission-recommended 400°C maximum temperature limit at various cooling rates. Before testing high-burnup cladding, four out-of-cell tests were conducted to optimize the hydride reorientation (R) test condition with pre-hydride Zircaloy-4 cladding, which has the same geometry as the high burnup fuel samples. Test HR-HBR#1 was conducted at the maximum hoop stress of 145 MPa, at a 400°C maximum temperature and a 5°C/h cooling rate. On the other hand, thermal cycling was performed for tests HR-HBR#2, HR-HBR#3, and HR-HBR#4 to generate more radial hydrides. It is clear that thermal cycling increases the ratio of the radial hydride to circumferential hydrides. The internal pressure also has a significant effect on the radial hydride morphology. This report describes a procedure and experimental results of the four out-of-cell hydride reorientation tests of hydrided Zircaloy-4 cladding, which served as a guideline to prepare in-cell hydride reorientation samples with high burnup HBR fuel segments. This report also provides the Phase II CIRFT test data for the hydride reorientation irradiated samples. The variations in fatigue life are provided in terms of moment, equivalent stress, curvature, and equivalent strain for the tested SNFs. The CIRFT results appear to indicate that hydride reoriented treatment (HRT) have a negative effect on fatigue life, in addition to hydride reorientation effect. For HR4 specimen that had no pressurization procedure applied, the thermal annealing treatment alone showed a negative impact on the fatigue life compared to the HBR rod.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). High Temperature Materials Laboratory (HTML)
- Sponsoring Organization:
- USDOE Office of Nuclear Energy (NE)
- DOE Contract Number:
- AC05-00OR22725
- OSTI ID:
- 1333100
- Report Number(s):
- ORNL/LTR--2016/660; AF5865010; NEAF346
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
AMPLITUDES
ANNEALING
BENDING
CIRFT test
COMPARATIVE EVALUATIONS
COOLING
DRYING
DYNAMIC LOADS
FATIGUE
FUEL CANS
FUEL RODS
HYDRIDES
IRRADIATION
MECHANICAL VIBRATIONS
MORPHOLOGY
ORIENTATION
PRESSURE DEPENDENCE
PRESSURE RANGE MEGA PA 100-1000
PRESSURIZATION
PROGRESS REPORT
ROBINSON-2 REACTOR
SERVICE LIFE
SIMULATION
SNF vibration integrity
SPENT FUELS
STRAINS
STRESSES
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0400-1000 K
TESTING
THERMAL CYCLING
TRANSPORT
VARIATIONS
ZIRCALOY 4
hydride reorientation