ML050240124

Slides for Palo Verde Meeting, Part 2 of 2

ML050240124
Person / Time
Site:	Palo Verde
Issue date:	12/09/2004
From:	Arizona Public Service Co
To:	Office of Nuclear Reactor Regulation
Fields M B ,NRR/DLPM,415-3062
References
Download: ML050240124 (12)

Text

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Dry Fuel Storage Update Palo Verde Nuclear Generating Station NRC SFPO Meeting December 9, 2004 I

2003 Review

+ Zero OSHA or lost time injuries

+ Loaded 10 casks

- 5 in Unit 2

- 5 in Unit 1 Parameters

- Max burnup 42,833 MWD/MTU, 11 kW

- Max total dose per canister 535 mR,

- Min total dose per canister 274 mR Vacuum drying routinely required 2 to 3 in-pool cooling periods per Amendment 2 of CoC Numerous procedure and process improvements 2

2004 Review

• Zero OSHA or lost time injuries incurred

+ Loaded 12 casks, developing extra pool space

- 6 in Unit 3, 6 in Unit 2

• Steady decline in dose received

- For canister 20, total dose was 95 mR

- Lowest found in industry, avg lows 242 mR New weld contractor in 2004

- Equipment upgraded to computer controlled

- Personnel more versatile Implemented UMS CoC Amendment 3

- One in-pool cooling period needed during vacuum drying

- Significant time savings aI, \\,

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2004 Events

• Experienced 250 gallons water in-leakage

• Single plant Tech Spec violation for siphon of 20 gallons of water from spent fuel pool

• Experienced slight loss of level in cask load pit (evaporation), below top of TFR

+ Procedures didn't require TFR to be submerged per Tech Spec

+ All issues related to in-pool cooling cycles

• Damaged vacuum pump 4 i

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Vacuum Drying Challenges

+ With CoC Amendment 2 required 2 to 3 LCO entries

+ After CoC Amendment 3 requires only 1 LCO entry

+ With CoC Amendment 4, should be able to meet criteria without LCO entry

+ Each LCO entry represents increased risk I/\1i/

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Vacuum Dryness

• Horizontal surfaces tend to hold water

+ Fuel design has water traps in dashpots

+ Current criteria is less than 3 mm Hg for 30 minutes

+ Amendment 4 requests criteria of less than 10 mm Hg for 10 minutes

- Same as NAC MPC criteria as currently approved by NRC

• RAI for Amendment 4 questions pressure rise

• Contributors to pressure rise

- Residual moisture

- Temperature rise

- System leaks

- Instrumentation Ia,,

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NAC UMS CoC Amendment 4

+ Benefits

- Vacuum drying criteria

- CEA guide tube inserts

- Eliminate seismic criteria

• Current issuance schedule won't support cask loading in 2005

- Starts January, ends August

- Amendment schedule projects August 2005

• RAI issues will require some technical evaluation al 7

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Self Audit Results

• No significant problems or program weakness found with the dry cask program

• Strong NFM program ownership noted

'Areas needing improvement

+ PM bases development and implementation

+ Equipment inspection implementation

• Records coding

• All issues have been evaluated, corrective actions are in progress 8

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Operating Experience

+ Utilize nuclear and non-nuclear experience reports

+ Inadvertent canister backfill with Argonne

+ Rail line issues

+ Transportability of MPC vacuum drying concerns to UMS

+ Issue of water collection in MPC VCC base plate during construction

+ VCC concrete spalling Is S *gL

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2005 Plans

+ Load 12 casks

- 6 in Unit 1, 6 in Unit 3

+ Avg dose goal is 125mR/cask

+ Receive UMS CoC Amendment 4

+ Improve vacuum drying process

• Reduce cask load costs

+ NRC inspection 1st qtr 10

.9 Future Needs

• Working to establish extra operating cycle of open space in the spent fuel pools

• PVNGS needs to load high burnup fuel by 2007

• Transition to a higher capacity cask by 2007

• CEA disposal option needed 11

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Cask Procurement

+ Anticipate contract award for high capacity cask by June 30, 2005

+ Chosen design to provide the following features:

- Bound PVNGS site parameters

- High burnup fuel to 60,000 MwDIMTU

- Enrichment to 5 wt %

- Placement of CEAs in fuel guide tubes

- Accommodate PVNGS CE 16X16 length

• No licensed cask meets all requirements, 12

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