ML15273A429
| ML15273A429 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 09/29/2015 |
| From: | William Allen Dominion, Virginia Electric & Power Co (VEPCO) |
| To: | Spent Fuel Licensing Branch |
| Allen W | |
| References | |
| Download: ML15273A429 (18) | |
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Agenda
- License renewal scope and timeline
- Lead cask inspection scope
- Inspection process/criteria
- Lead cask selection
- Schedule for inspections llilDh:.
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North Anna ISFSI License
- ISFSI license (SNM-2507) issued June 30, 1998, expires 2018
- Site-specific license includes only Pad 1 and the TN-32 casks
- Submit application by June 2016 3
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Lead Cask Inspections
- Guidance on lead cask inspections provided by:
- NUREG-1927, draft Revision 1, Appendix C
- Requests for Additional Information for Prairie Island License Renewal Application
- Lead cask inspections supplemented by
- Quarterly material condition surveillances
- Post-seismic event inspections on five TN-32 casks
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Scope of Lead Cask Inspections
- Lift a TN-32 cask and visually inspect bottom for coating adhesion and corrosion (i.e., loss of material)
- Remove a protective cover and visually inspect the following components for corrosion:
- Protective cover
- Neutron shield and neutron shield bolts
- Overpressure system components
- Visible lid sealing surface including lid bolts
- Visually inspect upper and lower trunnions for corrosion (loss of material)
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Lead Cask Inspections
- Visual inspections will be conducted by certified NOE personnel (i.e., VT-1 or VT-3)
- A mockup of the cask bottom was used to test inspection technique and ensure meeting NOE requirements
- Indications of corrosion or lack of coating adhesion will be recorded and a Condition Report submitted for disposition
- Description/resolution will be included in the license renewal application
- Cask handling will be conducted by qualified personnel 8
Lead Cask Selection
- Selection of lead cask based on degradation mechanism of concern (corrosion)
- Circumstances unique to the North Anna ISFSI result in the selection of two different casks for the bottom and the protective cover inspections
- August 2011 seismic event (5.8 magnitude earthquake centered near Mineral, VA)
- Replacement of nine protective covers in 2002-2003 with new protective cover design lilD~
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Selection of Lead Cask Bottom Inspection
- Factors contributing to selection of cask for bottom inspection :
- Accessibility for lifting
- Movement during seismic event
- Decay heat of the fuel in the cask
- Time since loading 10
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Selection of Lead Cask Bottom Inspection
- Based on the selection factors, cask TN-32.49 was chosen for bottom inspection
- One of four casks accessible with transporter
- TN-32.45 accessible now, but TN-32 high burnup demonstration cask will block it for future bottom inspections
- Moved the most of the accessible casks (3 inches) during seismic event
- Decay heat 29 KW when loaded
- Oldest of remaining accessible casks
- Best candidate with accessibility, movement during seismic event, high initial heat load, earliest loading date
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Selection of Lead Cask Bottom Inspection Accessible with Movement During Decay Heat When Cask Transporter Seismic Event (In) Loaded (KW) Date Loaded TN -32 .06 1.50 16.90 Jul 1998 TN-32 .10 2.50 18.28 Aug 1998 TN-32 .12 0.50 15.40 Jun 1999 TN -32.13 1.00 14.13 Jul 1999 TN -32.14 0.75 13.30 Dec 1999 TN-32 .16 3.50 15.39 Jun 2000 TN -32 .19 2.25 16.20 Aug 2000 TN-32.20 1.00 14.94 Sep 2000 TN-32 .21 4.50 21 .29 Jan 2001 TN -32 .23 3.50 17.96 Jul2001 TN -32 .24 3.00 22.15 Aug 2001 TN-32 .26 1.25 15.95 Jan 2002 TN -32 .29 2.00 13.62 Feb 2002 TN -32.30 TN -32 .32 c= 0.00 ~
1.50 13.92 13.84 Aug 2002 Nov 2002 TN-32 .36 4.00 28 .53 Jul2003 TN-32 .37 3.00 28 .89 Aug 2003 TN -32 .38 1.00 28 .72 Sep 2003 TN -32.41 TN-32.42 c= 0.00 1.50
=::::J 25 .62 25 .95 Dec 2003 Feb 2004 TN-32.43 3.50 26.01 Mar 2004 TN -32.45 Yes 1.50 26.21 Jun 2004 TN-32.47 1.00 26.43 Apr2005 TN -32.48 2.00 30.10 Jun 2006 TN-32.49 Yes 3.00 28.94 Aug 2006 TN-32 .52 Yes 2.00 30.66 Sep 2006
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TN -32 .53 Yes 2.50 20.70 Jan 2007 13
Selection of Lead Cask Protective Cover Inspection
- Factors contributing to the selection of the cask for protective cover inspection
- Time since cover installation
- Movement during seismic event
- Not inspected after seismic event
- Based on these factors, cask TN-32.23 was chosen for protective cover inspection
- Oldest installed protective cover
- Cask moved 3.5 inches during seismic event
- Not one of the five casks inspected after seismic event 14 .
Selection of Lead Cask Protective Cover Inspection Movement Inspected Date Protective During Seismic Following Cask Date Loaded Cover Replaced Event (In) Seismic Event Recoated in 2014 TN-32 .06 Jul 1998 Mar 2002 1.50 Yes TN -32 .10 Aug 1998 Mar 2002 2.50 TN -32.12 Jun 1999 Jun 2002 0.50 Yes TN -32.13 Jul 1999 May 2002 1.00 TN -32.14 Dec 1999 Jun 2003 0.75 Yes TN -32.16 Jun 2000 Jun 2003 3.50 TN-32.19 Aug 2000 Jun 2003 2.25 TN -32.20 Sep 2000 Jun 2003 1.00 TN -32 .21 Jan 2001 Jun 2003 4.50 Yes Yes TN-32.23 Jul2001 3.50 TN -32.24 Aug 2001 3.00 Yes
- Yes TN-32.26 Jan 2002 1.25 TN-32.29 Feb 2002 2.00 TN -32 .30 TN-32 .32 Aug 2002 Nov 2002 c 0.00 1.50
=1 Yes Yes TN -32.36 Jul2003 4.00 Yes TN -32.37 Aug 2003 3.00 TN-32 .38 Sep 2003 1.00 TN-32.41 TN-32.42 Dec 2003 Feb 2004 c 0.00 1.50
~ Yes Yes TN-32.43 Mar 2004 3.50 TN-32.45 Jun 2004 1.50 TN-32.47 Apr2005 1.00 TN-32.48 Jun 2006 2.00 Yes TN-32.49 Aug 2006 3.00 TN-32.52 Sep 2006 2.00 TN-32 .53 Jan 2007 2.50 Yes 15
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Lead Cask Inspection Schedule
- Planning for lead cask inspections substantially complete
- Inspection under protective cover of TN-32.23 scheduled for October 13 (weather-dependent)
- Inspection of bottom of TN-32.49 scheduled for October 14 17
Summary
- A detailed evaluation process was used to determine the lead cask(s) for inspection
- The two casks selected are believed to best meet our selection criteria, and are representative of the aging effects of concern
- Inspections will utilize industry-accepted standards and criteria to assess the cask conditions for license renewal
- Results to be included in License Renewal Application, submitted by June 2016
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