ML090720708
| ML090720708 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 03/12/2009 |
| From: | Plant Licensing Branch III |
| To: | |
| Wengert, Thomas J, NRR/DORL, 415-4037 | |
| References | |
| TAC ME0708 | |
| Download: ML090720708 (9) | |
Text
March 12, 2009 1
PRE-APPLICATION MEETING WITH ENTERGY NUCLEAR OPERATIONS, INC. (ENO), TO DISCUSS SPENT FUEL CRITICALITY AMENDMENT FOR PALISADES NUCLEAR PLANT (TAC NO. ME0708)
March 12, 2009
March 12, 2009 2
Overview
- Recent submittal for Region I:
- no Carborundum credit
- fresh fuel assumed with soluble boron
- resulted in 2/4 checkerboard pattern
- This submittal:
- include burnup credit
- include some Carborundum credit
- include soluble boron credit
- improve the storage capacity of Region 1
March 12, 2009 3
Programs
- KENO-V.a, SCALE 4.4a, with 44 group library
- Bias and uncertainty evaluation will follow closely the method shown in recent submittals.
- Guided by NUREG-6698: 100 benchmark problems (including MOX), trending analysis, normality, description of applicability.
- A benchmark including fission products is not considered necessary at this time.
- An equivalency method is used. In CASMO-3, an equivalent amount of (in-fuel) boron is determined to represent the reactivity effect of fission products.
- The KENO-V.a model does not explicitly contain fission products.
- 5% Bu uncertainty adequate conservatism for this application
March 12, 2009 4
Programs
- CASMO-3.
- Used to generate cross sections for the fuel cycle calculations.
- Will be used for generation of depletion inventories.
- NEMO and PRISM Topical Reports
- Will be used for tolerance calculations.
- Will include selected critical benchmarks
March 12, 2009 5
Assembly Selection
- Selection of limiting assembly type
- What is modeled, what is omitted
- End details (top & bottom nozzles) omitted
- Guide bars included
- Grid spacers being evaluated
- Conservatively assume a nominal maximum uniform (average) planar enrichment over the axial length and cross sectional area of the assembly.
- Review of assemblies in the pool, what is expected
- Consider special items (pin holders, lights, dummy assemblies)
March 12, 2009 6
Bias and Uncertainty
- Follows the methods outlined in recent AREVA submittals.
- Methodology Bias:
- from benchmarking and trending analysis for KENO-V.a
- Manufacturing Tolerance:
- rack tolerances: ID of cell, cell thickness, pitch, Carborundum
- assembly tolerances: w/o, pellet density, pellet radius, clad thickness, GT/IT thickness, guide bar
- System Parameters:
- moderator temp, off center assembly placement, rack interface, non-fuel bearing can, fuel assembly type and history
- All appropriately combined for K95/95
March 12, 2009 7
Analytical Requirements & Assumptions
- Will follow closely with recent AREVA submittals.
- Abnormal occurrences
- tipping or falling of assembly
- de-boration of pool
- misplacement of fresh assembly in rack
- misplacement of fresh assembly adjacent to rack
- stuck assembly (with uplifting force)
- off center assembly (horizontal movement)
- straight deep drop, drop through accident
- significant objects dropped in pool
- other
March 12, 2009 8
Analytical Requirements & Assumptions
- Burnup credit calculations:
- Explicit rack modeling with no leakage, or full reflection.
- design basis fuel assembly characteristics:
- 4.6 w/o
- active fuel length with no axial blankets
- no gadolinia bearing fuel rods
- soluble boron credit
- flat axial burnup profile at low burnups, explicit determination of the breakpoint, custom burnup profile used above the breakpoint.
- CASMO depletion performed with conservatively high moderator and fuel temperatures to maximize reactivity.
- 5% uncertainty on burnup.
March 12, 2009 9
Analytical Requirements & Assumptions
- Carborundum credit, derived from BADGER testing results.
- Appropriate swelling model