ML18338A067
| ML18338A067 | |
| Person / Time | |
|---|---|
| Issue date: | 12/11/2018 |
| From: | Billone M, Haile Lindsay NRC/NMSS/DSFM/IOB, US Dept of Energy, Office of Nuclear Energy |
| To: | |
| Lindsay H | |
| Shared Package | |
| ML18338A059 | List: |
| References | |
| Download: ML18338A067 (16) | |
Text
Sister Rod Destructive REG CON 2018 Examination Test Plans: Phase 1 NRC Headquarters Dec. 11, 2018 M.C. Billone
Background on Sister Rods
- DEMO CASK: SAFE STORAGE OF HIGH-BURNUP FUEL
- TN-32B cask loaded with 32 PWR fuel assemblies irradiated to high burnup in North Anna reactors
- Zircaloy-4 (Zr-1.5wt.%Sn), Low-Sn Zircaloy-4 (Zr-1.3 wt.%Sn)
- ZIRLO (Zr-1wt.%Sn-1wt.%Nb), M5 (Zr-1wt.%Nb)
- Cask has been monitored during drying and transfer to storage pad
- May be opened in 10 years for visual examination & characterization
- 25 SISTER RODS
- Extracted from DEMO Cask assemblies or from similar assemblies
- 2 Zry-4, 2 LT Zry-4, 12 ZIRLO and 9 M5 at 4959 GWd/MTU
- ORNL completed non-destructive examinations on all 25 rods
- 10 rods were shipped to PNNL
- One-half rod-equivalent of defueled cladding will be shipped to ANL 2 energy.gov/ne
Non-Destructive Examinations (NDEs) and DEs
- Detailed visual examinations and imaging
- Gamma scans
- Burnup profile
- Pellet-pellet interfaces and gaps
- grid spacer locations
- Eddy current measurements: lift-off (oxide & CRUD thickness)
- Lengths and outer diameters (profile) of fuel rods
- Surface temperatures
- Montgomery et al., Sister Rod Nondestructive Examination Final Report, SFWD-SFWST-2917-000003 Rev. 1, May 16, 2018
- Destructive Examinations (DEs)
- Plans for Phase 1; DE progress to date (ORNL presentation) 3 energy.gov/ne
Phase 1 Test Plan Objective for Sister Rods
- CHARACTERIZATION AND MATERIAL PROPERITES
- Generate data that can be compared to 10-year stored fuel rods
- Data for as-irradiated sister rods should be sufficient as baseline for DEMO rods because of low cladding temperatures (<250oC) for DEMO rods
- Generate data for cladding mechanical properties
- Baseline data for as-irradiated cladding at room temperature (RT) & 200oC
- Data for heat-treated cladding (400oC for 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />) at RT & 200oC
- DETERMINE: IS EMBRITTLEMENT DUE TO RADIAL HYDRIDES AN ISSUE?
- Heat-treat at 400oC (DSFM-recommended limit, 200 wppm H in solution) using actual rod internal pressures (RIPs) at RT (25oC)
- Peak RIP and cladding hoop stress @ 400oC are reasonable limits
- Cool at 5oC/h with decreasing RIP and hoop stress
- Use burst tests and ring compression tests to assess effects
- Note: RIP will be measured at 25oC for 18 fuel rods in Phase 1 4 energy.gov/ne
5 energy.gov/ne Hydride Orientation in Irradiated ZIRLO Cladding 320+/-30 wppm 320+/-30 wppm 650+/-180 wppm 650+/-180 wppm 6 energy.gov/ne
Radial Hydrides ino Irradiated ZIRLO following Cooling from 400 C Peak Cladding Temperature 480 wppm 88 MPa 9% of cladding wall 20% of cladding wall 32% of cladding wall 7 energy.gov/ne
Potential for Hydride Reorientation
- Radial-Hydride-Induced Degradation
- DEMO Cask fuel rods
- Peak cladding temperature (PCT) <250oC; <44 wppm H in solution
- Internal gas pressure <9 MPa; peak hoop stress <68 MPa
- Do not anticipate to observe radial-hydride-induced degradation
- Sister Rods
- PCT = 400oC; 200 wppm H; pressure <11.3 MPa; hoop stress <87 MPa
- Expect to observe radial hydrides
- Do not expect to observe radial-hydride-induced degradation
- Anticipated Range of Peak Cladding Hoop Stresses
- FRAPCON predictions for 400oC PCT and temperature profile
- <54 MPa for standard PWR rods; <89 MPa for IFBA rods with internal B-10
- Predictions based on end-of-life (EOL) rod internal pressure (RIP) data 8 energy.gov/ne
EOL RIP EPRI & Sister Rod Data 9 energy.gov/ne
Review of Hydride-Induced Ductility Degradation
- As-Irradiated Cladding
- Hydrides are primarily oriented in circumferential direction
- Short isolated radial hydrides have been observed in cladding (ZIRLO and M5 ) from PWR fuel rods irradiated to high burnup
- Conditions for Significant Radial Hydride Precipitation
- High enough (>60 wppm) hydrogen content and peak cladding temperature (PCT >285oC)
- High enough (>10 MPa) internal pressure at PCT
- High enough (>80 MPa) hoop stress @ PCT
- Radial hydride lengths and number density
- Ductility and ductility transition temperature (DTT) based on RCTs 10 energy.gov/ne
Future Hydride-Reorientation Testing
- ANL Cladding at 350oC PCT
- Critical stress for ZIRLO appears to be 90+/-3 MPa
- ZIRLO: test 350-wppm-H/93-MPa, 650-wppm-H/87-MPa
- ANL cladding is from lead-test-assembly rods at >62 GWd/MTU
- Sister Rod Cladding at 400oC PCT
- More prototypic linear power histories per fuel cycle (18 months)
- Wider range of hydride distributions through cladding wall
- More cladding samples available
- Allows for repeat tests and intermediate-temperature tests
- Allows for load-interrupt tests to better determine cladding ductility
- Offers the possibility of M5 with >100 wppm hydrogen 11 energy.gov/ne
Acknowledgement This work is supported by the Spent Fuel and Waste and Science Technology (SFWST)
Program (NE-81), Office of Nuclear Energy (NE-8) under Contract DE-AC02-06CH11357.
M.C. Billone Senior Mechanical Engineer Applied Materials Division Argonne National Laboratory 9700 S. Cass Ave., Bldg. 212 Argonne, IL 60439 630-252-7146 billone@anl.gov 12 energy.gov/ne
Questions?
13 energy.gov/ne
Radial Hydrides in ZIRLO for 400oC PCT 480 wppm 88 MPa
<20oC DTT 9+/-4% RHCF o 20oC DTT 20+/-10% RHCF 120 C DTT 32+/-13% RHCF 14 energy.gov/ne
Radial Hydrides in ZIRLO for 350oC PCT 28oC DTT 125oC DTT 20+/-10% RHCF 30+/-11% RHCF 140oC DTT 37+/-11% RHCF 15 energy.gov/ne
Ductility (Offset Strain) for ZIRLO vs. Test Temperature - DTT Determination 16 energy.gov/ne