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? 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. IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
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 MY Yankee Rowe 15 Spent Fuel Dry Casks 1 GTCC Dry Casks NAC MPC System CoC Expires 4/10/20 YR Connecticut Yankee Maine Yankee 40 Spent Fuel Dry Casks 60 Spent Fuel Dry Casks 3 GTCC Dry Casks 4 GTCC Dry Casks NAC MPC System NAC UMS System CoC Expires 4/10/20 CoC Expires 11/20/20 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- 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. IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
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 Third-Tier Crack IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
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 • Using EPRI Susceptibility Criteria, determine the relative ranking of canisters and their susceptibility to CISCC. • Results: • Maine Yankee: Z ISFSI = 2 / V can = 4-5 • Conn. Yankee: Z ISFSI = 1 / V can = 4-5 • Yankee Rowe: Z ISFSI = 1 / V can = 5 • Use this ranking, OE and known environmental characteristics of the ISFSI to develop a strategy for canister inspections. IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
-Site characterization for aging management- Maine Yankee Located on the Back River Brackish Water-Tidal About 12 miles from Open Ocean 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. IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
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 Atmospheric Chloride Concentration: Maine Yankee ISFSI & Acadia National Park CASTNET Site 2.5 Atmospheric Concentration (µg/m 3 ) 2 1.5 ANP High 1 MY ISFSI High ANP Low 0.5 MY ISFSI Low 0 Month 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 Elemental map of collected on 5 particles collected micron PTFE Filter 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
Wet Candle (Chloride Deposition Rate) Result Comparison Site Time period Distance to Range of values (mg/m 2 /day) source Maine Yankee ISFSI 2013-2017 19K meters (to 1.0 – 5.1 open ocean) Yankee Rowe ISFSI 2014-2017 160K meters 0.8 – 2.0 Kure Beach, NC 1962-1998 250 meters 50 - 200 (near-ocean) 1 Kure Beach, NC 1962-1998 25 meters 200 - 700 (oceanfront) 1 Cape Town, South 2013-2014 50 meters 126.69 Africa 3 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 IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
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
Surface Deposit Survey Chloride Concentration (mg/m 2 ) Site Maine Yankee 0-11 SMUD 5 18.5 Hope Creek 6 <2.5 -60 Diablo Canyon 6 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-7170 10 100 – 10,000 CRIEPI Threshold for 304L 11 800 IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
Canister Inspection Approach 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. IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
Canister Surface Inspection Footage (GTCC) 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. • IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
Canister Surface Inspection Footage Likely iron contamination • from initial fabrication. IAEA Technical Meeting on the Management of Spent Fuel at Shutdown Reactor Sites: 11-13 June 2018
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