ML18338A068

Presentation Slides: Status of Spent Fuel Cladding Tests

ML18338A068
Person / Time
Issue date:	12/04/2018
From:	Meraj Rahimi Renewals and Materials Branch
To:
Lindsay H
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Progress Report on Spent Fuel Cladding Integrity Tests Meraj Rahimi Chief of Renewals and Materials Branch Division of Spent Fuel Management Office of Nuclear Material Safety and Safeguards U.S. Nuclear Regulatory Commission

Spent Fuel Cladding Performance Safety Functions 2

Subcriticality Unsustainable fission reaction Confinement / Containment No release of radioactive material Radiation Shielding On-site worker and public dose limits Heat Removal Fuel temperature Cladding stresses December 11, 2018 DSFM REG CON 2018 Structural Performance Maintain analyzed configuration (no operational problems with respect to spent fuel removal)

ISG-11, Revision 3 Cladding Considerations (Peak Cladding Temperature / Thermal Cycling)

Dry Storage / Transport Spent Fuel Cladding Performance Review Guidance Framework 3

NUREG-2216 Standard Review Plan Transportation NUREG-2224 Dry Storage / Transportation High Burnup Fuel NUREG-2214 Managing Aging Processes in Storage NUREG-2215 Standard Review Plan Dry Storage December 11, 2018 DSFM REG CON 2018 Fuel temperature Cladding stresses

Spent Fuel Cladding Performance Technical Bases / Position 4

Hydride reorientation Delayed hydride cracking Thermal creep Low-temperature creep Mechanical overload Oxidation Pitting corrosion Galvanic corrosion SCC Radiation embrittlement Fatigue None of these mechanisms are expected to compromise cladding integrity during transportation and dry storage up to 60 years.

Data expected to confirm conclusions for dry storage beyond 20 years.

December 11, 2018 DSFM REG CON 2018 ISG-11, Rev. 3 1.

Peak cladding temperature /

Controlled hoop stresses 400 °C (758 °F) / 90 MPa 2.

Limited thermal cycling SRPs / MAPS Report 3.

Inert environment 4.

Limited residual water Considerations Performance-Related Phenomena ISG-11, Rev. 3, MAPS Report

Where to next?

5 What have we learned?

- Better understanding of hydride reorientation Additional confirmatory testing under DOEs Sister Rod Program

- Better understanding of rod internal pressures / gas communication

- Improved benchmarking of thermal models Revisit peak cladding temperatures

- Identifying new metrics for cladding performance (e.g., cladding stresses)

- Risk informing cladding performance (e.g., tolerance of peak cladding temperature, consequences to other safety disciplines)

- Defining staffs expectations for technical bases in support of a higher peak cladding temperature December 11, 2018 DSFM REG CON 2018