spent fuel management at “stand alone isfsi” sites
TRANSCRIPT
Spent Fuel Management at “Stand Alone ISFSI” Sites
By: Paul Plante, Project Manager
Connecticut Yankee/Maine Yankee/Yankee Rowe
IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
What is an Stand Alone ISFSI?
IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
It is a site where: • The reactor building and associated structures
have been decommissioned, • The associated waste has been removed, • The licensed facility has been reduced in size
and scope to an ISFSI. • The facility is in steady state, long term
operating mode awaiting fuel package removal by the federal government.
Before
IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
After
IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
The 3 Yankees
CY
YR Connecticut Yankee 40 Spent Fuel Dry Casks 3 GTCC Dry Casks NAC MPC System CoC Expires 4/10/20
Yankee Rowe 15 Spent Fuel Dry Casks 1 GTCC Dry Casks NAC MPC System CoC Expires 4/10/20
Maine Yankee 60 Spent Fuel Dry Casks 4 GTCC Dry Casks NAC UMS System CoC Expires 11/20/20
MY
IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
Cask System Life Cycle at ISFSI Only Sites • Initial 20 year license life.
During this time, inspection and maintenance requirements are found in the initial Certificate of Compliance (CoC) or Site Specific License and the FSAR.
• Period of Extended Operation (40 years) During this time, revised inspection and
maintenance plans will be found in the renewed CoC or Site Specific License and the FSAR.
IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
Spent Fuel Issues for Stand Alone ISFSI Sites
• Cask system maintenance, inspections and repairs.
• Dry storage system amendments and relicensing.
• Aging management for dry storage systems. • Canister susceptibility to aging mechanisms
(Such as CISCC). • Site characterization for aging management. • Potential repair and mitigation issues.
IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
-Cask system maintenance and inspections-
IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
Requirements for the initial 20 yrs. are in the CofC and FSAR: • Cleaning and sealing casks and pads, • Annual Inspections of the casks and pads, • Coating repairs, • Concrete repairs when necessary, • Temperature monitoring system maintenance
and upgrades.
Typical Vertical Concrete Cask
IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
Cask system maintenance and inspections
IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
Examples of Reportable Tier 3 Damage
IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
Third-Tier Crack
Pad Delamination From Original Construction
IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
-Dry Storage System Amendments & Relicensing-
• Complicated and ever evolving. • NRC developing and revising NUREG’s. • NEI 14-03 Guidelines to the industry. • EPRI activities and the technical basis for
relicensing. • ASME Code Case development. • Sometimes involves amendments to address
operating issues.
IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
-Aging Management for Dry Storage Systems-
• Will require new site specific program and procedures to be integrated into the existing site architecture.
• Will be based on a standardized approach identified in the MAPS NUREG and NEI 14-03 Industry Guidance.
• Canister Inspections will be based on EPRI Aging Management Program published in March, 2017 and eventually on ASME Code Case N-860.
IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
Aging Management Approach
IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
Canister susceptibility to aging mechanism-SCC
IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
• Using EPRI Susceptibility Criteria, determine the relative ranking of canisters and their susceptibility to CISCC.
• Results: • Maine Yankee: ZISFSI = 2 / Vcan = 4-5 • Conn. Yankee: ZISFSI = 1 / Vcan = 4-5 • Yankee Rowe: ZISFSI = 1 / Vcan = 5
• Use this ranking, OE and known environmental characteristics of the ISFSI to develop a strategy for canister inspections.
Maine Yankee Located on the Back River Brackish Water-Tidal About 12 miles from Open Ocean
IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
Determine the nature of the site environment: - For use in EPRI susceptibility rankings. - To determine the significance of Operating experience from other sites. - To assess the nature of the site using technical literature on atmospheric corrosion.
-Site characterization for aging management-
Atmospheric Sampling Program • Started in August 2012. • Utilizes a Hi-Q continuous
duty air sampler. • Adjustable flow 20-100 lpm
IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
Seasonal Comparison of Atmospheric Conditions
0
0.5
1
1.5
2
2.5
Atm
osph
eric
Con
cent
ratio
n (µ
g/m
3 )
Month
Atmospheric Chloride Concentration: Maine Yankee ISFSI & Acadia National Park CASTNET Site
ANP High
MY ISFSI High
ANP Low
MY ISFSI Low
IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
SEM/EDS Analysis of Atmospheric Samples Typical particles collected on 5 micron PTFE Filter
Elemental map of particles collected
Chloride-containing particles isolated
IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
Atmospheric Chloride Deposition: Wet Candle Testing
• Based on ASTM G140-02
IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
Wet Candle (Chloride Deposition Rate) Result Comparison Site Time period Distance to
source Range of values (mg/m2/day)
Maine Yankee ISFSI 2013-2017 19K meters (to open ocean)
1.0 – 5.1
Yankee Rowe ISFSI 2014-2017 160K meters 0.8 – 2.0
Kure Beach, NC (near-ocean) 1
1962-1998 250 meters 50 - 200
Kure Beach, NC (oceanfront) 1
1962-1998 25 meters 200 - 700
Cape Town, South Africa3
2013-2014 50 meters 126.69
2013-2014 150 meters 27.26
2013-2014 250 meters 30.87
2013-2014 2.7K meters 11.23
2013-2014 13.5K meters 10.54
Surface Salt Sampling - Methods
2014 Sampling Event:
Wipe samples were collected using PTFE, dry cellulose, and wetted cellulose media
Samples collected from vertical and horizontal vent surfaces
2016 Sampling Event:
Objective: collect measurements on vents, shield plug, and from within canister in coordination with EPRI NDI robot demonstration
Tested surfaces: Inlet & outlet vents on three storage casks:
VCC2 inlet & outlet
VCC9 inlet & outlet
VCC20 inlet & outlet
Shield plug
Coated steel cask base
Analysis Laboratory analysis of chloride content
Elcometer in-situ analysis
SEM/EDS analysis of cask interior sample
IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
Site Chloride Concentration (mg/m2)
Maine Yankee 0-11
SMUD5 18.5
Hope Creek6 <2.5 -60
Diablo Canyon6 2.0 – 58
Calvert Cliffs 7 < 50
Koeberg (Winter) 8 1,000 – 2,000
Koeberg (Summer) 8 2,500 – 5,000
Kure Beach (25m)9 76,000 – 228,000
Kure Beach (250m)9 21,000 – 60,000
NUREG/CR-717010 100 – 10,000
CRIEPI Threshold for 304L11 800
Surface Deposit Survey
Canister Inspection Approach
IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
• The ROV was fitted with a borescope camera for inspections. • It can traverse 90° turns for navigating through the inlet and outlet vents
and is driven by magnetic wheels for vertical runs on carbon steel surfaces.
Canister Surface Inspection Footage (GTCC)
IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
• Left view shows manufacturer’s identification number stamped on canister shell showing detail of inspection capability.
• Right view shows junction of a canister vertical and horizontal seam weld.
Canister Surface Inspection Footage
IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
• Likely iron contamination from initial fabrication.
Potential repair and mitigation issues.
IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
Industry initiatives to identify and scope various: repair options such as: mitigation options such as:
Welded repairs Peening or Burnishing Thermal Spray Coatings Brazing/soldering Contaminate traps Patch Repairs Periodic surface cleaning Non-metallic Encapsulation or coatings
Potential repair and mitigation issues.
IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
One example: Failed Canister Over-pack at Maine Yankee
Summary
IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
• Even in steady state ISFSI Only status, there are many issues requiring attention: • Involvement in industry activities particularly for
areas where policy is being developed. • Working with industry partners as well as
government agencies. • Supporting research and development on tools to
ensure long term adequacy of dry storage systems.
Abbreviations and Acronyms
IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
• ASME: American Society of Mechanical Engineers • ASTM: American Society for Testing and Materials • CISCC: Chloride Induced Stress Corrosion Cracking • CoC: Certificate of Compliance • EPRI: Electric Power Research Institute • FSAR: Final Safety Analysis Review • GTCC: Greater Than Class C Waste • ISFSI: Independent Spent Fuel Storage Installation • MAPS: Managing Aging Processes NUREG Document • MPC: Multipurpose Canister System • NAC: NAC International • NEI: Nuclear Energy Institute • ROV: Remote Operated Vehicle • SEM/EDS: Scanning Electron Microscopy/Energy Dispersive Spectroscopy • UMS: Universal Multipurpose Storage System
Spent Fuel Management at “Stand Alone ISFSI” Sites
By: Paul Plante, Cask Relicensing Project Manager
Connecticut Yankee/Maine Yankee/Yankee Rowe
IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018