Dry Cask Storage

Defense-in-Depth

Jerry Stephenson

Manager, ISFSI Engineering

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Dry Cask Storage Defense-in-Depth

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SCE’s Requirements for Dry

Cask Storage Systems

• SCE goal is to ensure fuel is prepared for both onsite and offsite storage

• Selection criteria

– Must be currently licensed for storage and transportation (at time of selection)

– Must meet SONGS seismic criteria

– Long enough to accommodate SONGS fuel assemblies

– Low Dose Rates

– Strong presence in the U.S. Nuclear industry

• Systems that did not meet criteria were disqualified

• Three vendors were identified that met the requirements

– AREVA (Now Orano,also called TN Nuhoms)

– Holtec

– NAC International

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Bolted-Lid Cask Limitations

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DOE Atlas Railcar

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Railcar can accommodate Orano and Holtec transportation casks

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• Design specifications– Licensed for storage and transportation

– Higher seismic design based on local seismic conditions

– Thicker shell at 5/8-inch vs standard 1/2-inch

– 316L low-carbon stainless steel for improved corrosion resistance

• Less susceptible to corrosion

• Holtec fabrication enhancements to address chloride-induced stress corrosion cracking– Laser peening to eliminate surface stresses

– Two-pass weld technique to minimize heat affected zone

– Shell over-rolling

Specifications

for Dry Cask Storage System

Safety and Technical FeaturesDry Cask Storage Systems at SONGS

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Chloride Induced Stress

Corrosion Cracking (CISCC)

• CISCC requires three conditions to start:– Salt and water environment

– Susceptible material

– Tensile stresses in steel to enable crack to grow

• No instances of CISCC have been identified on canisters during inspections conducted to date

• Several design & fabrication improvements minimize potential for development of canister flaws

• 316L is resistant to CISCC

• Peening results in compressive stresses versus tensile stresses

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Fabrication Improvement:

Peening Canister Welds

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Canister Inspection

• Loaded canisters have been inspected worldwide

– Both horizontal (TN NUHOMS) and vertical (Holtec) systems have

been robotically inspected

– 8 Holtec UMAX canisters inspected at SONGS in 2019

• Canister Inspections will continue at SONGS in 2021

– TN NUHOMS baseline inspection for aging management program

(AMP)

– Holtec UMAX as designated by inspection & maintenance (I&M)

plan in 2024

• Robotic systems are currently available for these inspections

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SCE Inspection Developments

• Holtec UMAX

– Implemented: SCE demonstrated that detailed visual inspections can be

performed at SONGS

– 8 canisters inspected in early 2019

– Available: Eddy current, ultrasonic inspection, and mitigation

technology available, if needed

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SCE Inspection Developments

• TN NUHOMS

– Implemented: Other utilities have performed detailed visual

inspections with robotic technology

– Available soon: Inspection Ring undergoing final testing, will be

available for SONGS use in 2020

• First TN NUHOMS Inspections planned for 4Q 2021

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Orano Inspection Ring

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Orano Inspection Ring

• Orano Inspection Ring developed for the SONGS TN

NUHOMS System

– Allows for more detailed inspections if degradation is discovered

during initial robotic inspection

• Can perform more detailed Visual, Eddy Current, and Ultrasonic

inspections as necessary

• Remediation will also be available before 2021 planned

inspections

– Status

• Final Performance Testing will occur 4th Quarter 2019

• Inspection Ring will be operational and ready for deployment by

end of 2019

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RemediationAddressing Potential Flaws

• SCE and nuclear industry are actively working to develop

remediation techniques to address a potentially degraded

canister

1. Robotic weld repair

• Mounted on inspection ring (Orano) or mobile robotics (Holtec)

2. Nesting or over-pack

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Canister Remediation

• Remediation capability will be available in time to support

planned Orano inspections and Holtec I&M Plan submittal

– Orano TN/NUHOMS

• Inspections planned for 4Q 2021

– Holtec/UMAX

• I&M Plan submittal to CCC planned for October 2020

• Inspections based on I&M Plan, likely next inspections in 2024

–5-year inspection interval

–Regulations require first inspections in 2035

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BREAKInformation Booths Available

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Public Comment

Submit written comments to: nuccomm@songs.sce.com

For Internal Use Only

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CLOSING COMMENTSDAVID VICTOR AND DOUG BAUDER

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CEP Meetings

Topics Timing

Fuel Transfer Operations & Path Forward 6-5-19

Defense-In-Depth for Dry Cask Storage 8-22-19

SONGS Strategic Plan & the State of Private

Consolidated Interim Storage

11-21-19

Dry Fuel Storage Safety Workshop 1Q 2020

For Internal Use Only

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For Internal Use Only

Acronyms

For Internal Use Only

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APPENDIX

MCB Camp Pendleton22 Aug 2019

SONGS CEP Meeting

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MCB Camp Pendleton Population: 85,650

Marines 38,802 Navy 4,177 Civilian 6,350 Army/Air Force 21Family members 36,300

Daily population surges well above 86,000

Numbers as of Feb 2019

Local Communities Population Oceanside 178,240 San Clemente 66,245 Fallbrook 31,707

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For Internal Use Only

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FUEL TRANSFER OPERATIONS

Used Fuel

Readiness for Transportation

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• Some fuel qualified for transport now

• Remaining fuel qualifies over time

NOW ‘20 ‘21 ‘22 ‘23 ‘24 ‘25 ‘26 ‘27 ‘28 ‘29 ‘30 TOTAL

Units 2/3AREVA NUHOMS 24PT4

Unit 1AREVA NUHOMS 24PT1

Units 2/3HOLTEC MPC-37

6

1 95

1167 2 2

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17

73

33

2

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For Internal Use Only

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DRY CASK STORAGE

Dry Cask Storage

Holtec License Renewal Plan

• Holtec Inspection and Maintenance (I&M) Plan– Required for California Coastal Commission (CCC) coastal

development permit

• Must be submitted to CCC by 10/6/2020

• Four elements are required for I&M Plan

– Canister inspection, monitoring, and maintenance techniques

– Data that will be collected, and frequency of submission to CCC

– Available evidence related to the physical condition of the casks

– Remediation measures that will be implemented if canister condition is not sufficient to allow on-site and off-site transportation

– Will be implemented after CCC approval of plan• I&M Plan will be effective for initial license period (until 10/15/2035)

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Dry Cask Storage

Orano License Renewal Plan

• ORANO TN/NUHOMS/ License Renewal Application under review

by NRC

• Submitted by SCE to NRC May 2019

• 18-24 month review (normal NRC schedule)

• License expires 2/5/2023

– CA coastal development permit (CDP) renewal for NUHOMS system

• CDP application will be filed after NRC license renewal

• Submittal of CDP by SCE planned for 2/2022

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Sites Which Have Performed ISFSI

Canister Robotic Inspections

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Orano

Storage Module and Canister

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Outlet Vent

For Internal Use Only

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SONGS EMERGENCY SIRENS

This information is summarized in CEP Decommissioning Update handout

SONGS Emergency Sirens

• Fifty alert sirens depowered in local communities July 1, 2019

• NRC and Federal Emergency Management Agency (FEMA)

determined sirens were unnecessary

• Accident at defueled plant no longer exceed Environmental

Protection Agency (EPA) protective action guidelines (PAG) that

recommend evacuation or sheltering in place

• No credible radiological release beyond site boundary

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SONGS Emergency Sirens

• Sirens only were to be activated for two highest emergencies

– Site and general emergency

• Neither can occur at SONGS now that reactors are retired

– Sirens never activated due to an emergency in 39 years of service

• SONGS continues to maintain a robust emergency planning and

preparedness program

• More on emergency planning during decommissioning:

– https://www.songscommunity.com/safety/emergency-planning58

For Internal Use Only

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WHEELER NORTH REEF

EXPANSION PROJECT UPDATE

This information is summarized in CEP Decommissioning Update handout

Reef Expansion Project

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Reef Expansion Project

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Links to Important Topics on

SONGScommunity.com

• SCE White Paper on Incidental Canister Contact - June 3, 2019

– https://www.songscommunity.com/internal_redirect/cms.ipressroom.com.s3.amazonaws.co

m/339/files/20195/Effects%20of%20Incidental%20Contact%20White%20Paper%20FINAL

%20060319.pdf

• Drop Analysis of Fully Loaded Multi-Purpose Canister (Model MPC-37)

– https://www.songscommunity.com/internal_redirect/cms.ipressroom.com.s3.amazonaws.co

m/339/files/201810/Non-

proprietary%20SCE%20Summary%20of%20Hypothetical%20MPC-37%20Drop%2011-19-

18.pdf

• Frequently Asked Questions https://www.songscommunity.com/need-to-know/faq

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