ML030640716

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Meeting Slides Regarding Selective Implementation of the AST for the Point Beach Fuel Handling Accident
ML030640716
Person / Time
Site: Point Beach  NextEra Energy icon.png
Issue date: 02/06/2003
From:
Nuclear Management Co
To:
Office of Nuclear Reactor Regulation
References
Download: ML030640716 (21)
v • d • e


Text

Selective Implementation of AST for the Point Beach Nuclear Plant Fuel Handling Accident February 6, 2003 NMc Committed to NuclearExcellenc>e 1

Introduction

Purpose:

  • Discuss Selective Implementation of AST for the Fuel Handling Accident Analysis at PBNP NMC PBNP Representatives
  • Sara Scott (Radiological Analysis Engineer)
  • Jack Gadzala (Licensing Manager)

LisaaSchbfield (Licensing Engineer)

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NMC Committed to NuclearExcellnc>e

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Background

"* February 28, 2002, LAR 224 submitted to NRC

" Requested implementation of AST for a limited number of the design basis accidents

" Requested changes to various TS

"* Discussions with NRC staff following submittal resulted in staff requesting additional information

"* Approach

  • LAR 224 was retracted (1/24/2003)
  • Analyses to be resubmitted in two parts i.;*...Fuel, Handling Accident II *,*,:Remaining :Analyses (LOCA, MSLB, SGTR, LR, ORE)

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Topics of Discussion

"* Current Licensing Analysis

"*Proposed Fuel Handling Accident

" Proposed FHA Dose Results

"*Atmospheric Dispersion Factor Basis

"*Control, Room Envelope and HVAC

"*Proposed Technical Specification Changes

"*Commitments Conclusion t

FHA Current Licensing Basis

"* Thermal Power Level 1548.9 MWt (102%)

"* Accident Occurs 161 hours0.00186 days <br />0.0447 hours <br />2.662037e-4 weeks <br />6.12605e-5 months <br /> post-shutdown

"* All rods in one assembly damaged

"* NG gap inventories based on RG 1.25

"* Radial peaking factor of 1.77 applied

  • Overall pool DF of 100 for iodine (none for NG)

" Activity isreleased in 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />

.*'ICRFP30:iodine DCF used for thyroid doses 5

FHA Current Licensing Basis Doses Whole Body Thyroid Exclusion Area 0.23 rem 75 rem Boundary Low Population Lowl 0.14 rem 4.5 rem Zone Control Room Dose not specified, but FHA is not limiting

,,,F. ,.. 75 rem 300 rem L1..1imits 6

Proposed FHA Analysis

"- RG 1.183 Appendix B guidance followed

"*Parameters for Source Term

  • Core Power Level of 1683 MWt
  • Radial Peaking Factor of 1.8

+ All Rods in One Assembly Damaged

  • Decay time of 65 hours7.523148e-4 days <br />0.0181 hours <br />1.074735e-4 weeks <br />2.47325e-5 months <br />
  • RG 1.183 Gap Fractions and Chemical Forms

. Water Depth (minimum) 23 feet

-Effective Pool DF for Iodine is 200

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"Effect 0iPool DF for NG is 1 ni, L 7

Proposed FHA Analysis

"* Release Point

"* Unit 2 Purge Stack (bounding)

"* No Credit for Purge Stack Filtration

  • 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> Release Duration

"* CR HVAC

  • Emergency Mode Actuated at 10 min Post-Accident
  • 4550 cfm Filtered Intake
  • 500 cfm Unfiltered Inleakage
  • 95% Elemental and Organic Iodine Filter Efficiency 99%,Particulate Iodine Filter Efficiency

.. NoCredittfor the Administration of KI

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Proposed FHA Dose Results TRE 1.183 Accept.

TEDE Criteria Exclusion Area < 2.0 rem 6.3 rem Boundary LowPopulation < 0.5 rem 6.3 rem Zone Control Room < 3 rem 5 rem I_____________________________

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Offsite 7/Q Basis

  • EAB/LPZ values consistent with CLB LOCA
  • Submitted to the NRC as part of TSCR 192 (SW Pump Operability Requirements)
  • Analysis approved as amendments 174/178 (July, 9,1997)

, RG. 1..145 used to calculate EAB and LPZ X/Q's

  • 1/1/1991 to 12/31/1993 Primary Tower Met Data ialues based on True North

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Control Room x /Q Basis

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, Values were developed using ARCON96

  • 1/1/1997 - 12/31/1999 Primary Met Data Used

. Most of December 1999 data unavailable from Primary Tower

+ Unavailability due to implementation of digital recorders (replaced strip charts)

+ Overalldata recovery > 90%

  • Stability class determined from temp difference

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Control Room {IQ Basis

.M Possible Release Paths for FHA

"*Unit 2 Purge Stack

"*Spent Fuel Pool Deck

"*Drumming Area Vent Stack

"*All release points treated as Ground Release

"* Plume centerline transported directly over CR intake mAll releases influenced by Building Wake

,- .,*,,*+++,*+:,,+ onta nM, e n t Building for U2 Purge Stack / DAVS S......"

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  • PAB for:S'FP Deck

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Control Room { /Q Basis m ARCON96 default wind direction range of 90O

  • Values based on True North m ARCON96 default parameter changes based on DG-1111

, Surfaceroughness length set equal to 0.2 m

  • Sector, averaging constant set equal to 4.3 m Unit 2 Purge Stack represents most bounding

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Control Room Envelope and HVAC

  • Designed and Licensed under PBNP GDC 11
  • Includes provisions for continuous occupancy under any credible post-accident condition
  • No dose value associated with PBNP GDC 11

- Envelope contained in control building

  • Control Room Proper Computer Room

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.: ReactortEng ineering Room CR. Ventilation Duct Work 14

Control Room Envelope and HVAC m CR HVAC System provides heating, ventilation, air conditioning, and radiological habitability m CR HVAC has 4 modes of operation

  • mode 1: Normal mode
  • mode 2: 100% recirculation
  • mode 3: 25% filtered return air / 75% recirc
  • mode 4: 25% filtered outside air /75% recirc; positive pressure > 1/8 in w.g.
  • Actuated on high rad signal

"."HVA*C " ducwork design/construction considered comm r'c"i:a S-Slip and Drive joints I 15

Control Room Envelope and HVAC

  • Modifications
  • Hardcasting of the majority of the seams of the ventilation ductwork
  • Installation of new balancing dampers
  • Installed position indication for washroom exhaust fan isolation
  • New fusible links installed in the equipment room

"-,_,, roof penetrations i.Reilaced CR to Turbine Bldg differential pressure CR**

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Control Room Envelope and HVAC

[] Benefits of modifications made to CR/HVAC

+ Increase system reliability

  • Improve program implementation
  • Gain system operating margin

+ Increase integrity of CR HVAC system 10,

Proposed Technical Specification Change

[] Deletion of TS 3.9.3, "Containment Penetrations" (Refueling Operations)

  • Currently Requires
a. Equipment hatch closed and held in place with all bolts
b. One door in each air lock capable of being closed c.. Containment Purge/Exhaust penetration closed by a manual or automatic isolation valve...or capable

,........ ,,.o,,e. g closed by an OPERABLE isolation

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Proposed Technical Specification Change

  • Technical Support for Deletion
  • Revised analysis does not credit

"* Closure of the equipment or personnel hatches

"* Isolation of the purge stack

  • Ventilation system filtration of the release Although the SFP release is not limiting, this area does not-have closure requirements during refueling- operations

,t  ; D*;"+rum- ming, Area Vent Stack does not have automati isolation 19

Commitments

  • A supplement to the proposed submittal which addresses the remaining accidents of concern
  • LOCA
  • LockedRotor
  • ControlRod Ejection 1

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Conclusion

"*PBNP requesting Selective Implementation of AST for the Fuel Handling Accident

"*No exceptions to RG 1.183 are taken

"*Calculated doses do not challenge the limits specified in 10 CFR 50.67

, Revised: analysis supports deletion of TS 3.9.3

  • PBNP commits to submitting a supplement to the proposed-LAR to address remaining analyses
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