ML022970049
| ML022970049 | |
| Person / Time | |
|---|---|
| Site: | River Bend  |
| Issue date: | 10/08/2002 |
| From: | Entergy Operations |
| To: | Office of Nuclear Reactor Regulation |
| Webb M, NRR/DLPM, 415-1347 | |
| Shared Package | |
| ML022980196 | List: |
| References | |
| Download: ML022970049 (30) | |
Text
Agenda
- Introduction
- Participants
- Purpose
- River Bend General Plant Layout
"* Licensing Background
"* Proposed TS Changes
"* Discussion of Analyses 1
River Bend Station Full Scope Application of Alternate Source Terms Presented to USNRC By Entergy October 8, 2002 I
Licensing Background Use of alternate source terms
- Limited scope application at RBS (IFTS)
Use of fuel decay times in FHA
- Initial License: TS required 24-hour decay time before allowing fuel movement. TS requirement was removed by ISTS.
- Amend. 35 (1989): Allowed LLRT of vent and drain lines 80 hours9.259259e-4 days <br />0.0222 hours <br />1.322751e-4 weeks <br />3.044e-5 months <br /> after fuel decay.
2 I
Licensing Background
- Use of fuel decay times with AST Shutdown 24hrs X fuel decay period Typical non-AST Physical TS Controls Apply restnctions
& 24 hr limit on fuel movement 24 hr fuel Shutdown decay penod Decay Time w/AST Shutdown controls apply per commitments to NUMARC 93-01 movement 3
.Licensing Background
- Use of fuel decay times (cont.)
-Amend. 85 (1996): Allowed PC airlocks to be open 11 days after fuel decay.
-Amend. 113 (2000): Fuel Building & FBV not required 11 days after fuel decay.
-Amend. 119 (2001): TSTF-51 applied to containment. Committed to shutdown controls per NUMARC 93-01, including having ventilation and radiation monitoring systems available.
Shutdown controls apply per commitments to NUMARC 93-01 X
fuel decay penod
4 Proposed TS Changes
- Automatic actuation not required for:
- secondary containment isolation
- SGTS
- CRFA
- FB isolation & FBV not required
- FBV will continue to be available per committed shutdown controls.
Proposed TS Changes
" CRFA, containment, air locks, and power support systems not required for fuel movement.
"* New single MSL limit established.
" Aux. Building drawdown time increased (18.5 seconds to 34.5 seconds).
5 Proposed TS Changes Leakage rate limits revised:
- Containment Leakage (0.26 to 0.325%/day)
- Secondary cont. bypass (170k to 580k cc/hr)
-Annulus bypass leakage limits not required
- PC airlock seals (1.28 to 1.50 psig/day)
- Drywell airlock seals (0.67 to 20.0 psig/day)
Proposed TS Changes
- Ventilation filter testing program revised:
- increased allowable penetration of SGTS filters (0.5% to 5.0%) & CRFA filters (0.5%
to 1.0%)
- eliminates FBV filter testing (testing will be per FSAR commitment to RG 1.140 for normal ventilation systems)
6 River Bend Station Alternate Source Term Full Scope Implementation Analyses Introduction
"* Summary of Analyses
"* Suppression Pool Post-LOCA Chemistry
"* Atmospheric Dispersion Factors
"° Dose Analyses
- Common Assumptions
- Control Room Modeling
7 Summary of Analyses
"* Suppression Pool Chemistry Analysis
"* Atmospheric Dispersion Factors (x/Q)
"* Loss of Coolant Accident (LOCA) Off-site and Main Control Room (MCR) Doses
"* Fuel Handling Accident Off-site and MCR Doses
- Light Load Drop Analysis (LLA)
Summary of Analyses Control Rod Drop Accident (CRDA) Off Site and MCR Doses
- Design Basis CRDA
- Low Power CRDA Main Steam Line Break (MSLB) Off-Site and MCR Doses
- Equilibrium Iodine Case
- "Iodine Spike" Case
8 Suppression Pool pH Analysis
"* Performed I.A.W. NUREG/CR-5950
"* Severe Accident Procedures Already Direct Operators to Initiate System
" Release Fractions Consistent with Gap and EIV Release Fractions Initial Suppression Pool pH = 5.3
"* Total Exposed Cable Mass = 38,000 Ibm Bounding Dose Rates Used for Radiolysis pH Analysis - SLCS
"* SCLS Not Credited for 2 Hours
"* Injection Rate is 41.2 gpm
"° Minimum Sodium Pentaborate Weight %
in Solution is 7.13%
"* Minimum SLCS Volume of 1657 gallons injected
"* Buffering by CsOH was Neglected
9 pH Analysis - Results
- Final Calculated pH was 8.13
- Parametric Study Demonstrated <30% of the Sodium Pentaborate is Needed to Maintain pH > 7.0.
Atmospheric Dispersion Factors (X/Q) Analyses
"* NRC Codes Used in Analyses
- Off-site Analyses - PAVAN
- MCR Analyses - ARCON96
"* Main Control Room X/Q Values Calculated Using NUREG/CR-6331
"* Off-Site Values Consistent with Regulatory Guide 1.145 Requirements
10 x/Q Analyses - Data Environmental Data Taken from Plant I
Meteorological Tower
- Meets RG 1.23 Requirements (USAR Table 1.8-1 and Section 2.3)
Five Years of Data Used
- Off-Site used JFT: 1994-1999
- MCR Used Hourly Data: 1995-1998, 2000
,/Q-Release Points
"* Main Plant Stack (SGTS Release Point)
"* Radwaste Build
"* Turbine Building
- Main Steam Tunnel Blowout Panel
- Edge of Containment (Equipment Hatch)
- Standby Cooling Tower
- Fuel Building (MCR Only)
11 X/Q - Other Assumptions
"* "Ground Level" Release Assumed
" "Point Source" Release Assumed
"* MCR Values Calculated for Both Intakes:
- Main (Local) Air Intake (Control Building Roof)
- Remote Air Intake (Standby Cooling Tower)
" Shortest Distances Used in All Directions for Off-Site Calculations
PAP BLDG tug S-CNDS STOR THIS FIGURE IS INTENDED TO SHOW GENERAL BUILDING LAYOUT P
qAO S'TE BLDG TURBINE BUILDING RELEASE POINT FOR MAIN AIR INTAKE lJTURBINE BUILDING RELEASE POINT FOR REMOTE AIR INTAKE FUEL BUILDING RELEASE LOCATION FOR REMOTE AIR INTAKE MAIN PLANT STACK (SGTS)
RELEASE LOCATION MAIN STEAM TUNNEL PRESSURE RELEASE PANELS I
1 X/Q - Results Results More Favorable Than Initial Licensing Analyses MCR Values
- SGTS/Containment was 50% and 20% of Current Values for MAI/RAI
- NUREG/CR-6331: Murphy & Campe Overpredicted Conc. in Low Wind Speed Conditions (1.3 mph/0.58 mps)
Dose Common Assumptions
"° Power Level for Source Term is 3,100 MWt
- 102% of Current Licensed Thermal Power
- Also bounds Appendix K Power Uprate
"* DCF Based on FGR 11&12
"* Breathing Rates from RG 1.183 (RG 1.3)
2 CRFA Model - Normal Mode
"* RBS has a Positive Pressure Control Room
- Maintained >1/8"
"* Normal Intake of 2,000 cfm from Control Building Roof
"* No Filtered Recirculation
- Normal Discharge is 2,000 cfm.
CRFA - Emergency Mode
"* Only Credited in LOCA and CRDA
- No credit for Automatic Initiation signals taken
"* Maintains +1/8" per TS 3.7.2
"* Filter Efficiencies:
- Charcoal Efficiency of 98%
- HEPA Efficiency of 99%
3 CRFA - Emergency Mode
" Actual ESF Filter Flowrate is 4,000 cfm
- 50% Intake and 50% Recirculation
"* Assumed Unfiltered Inleakage is 300 cfm
"* Modeled Flows:
- Unfiltered Inleakage = 300 cfm
- Filtered Intake = 2000 - 300 = 1700 cfm
- Recirculation = 2000 cfm
- Discharge = 2000 cfm
SIMULATED C 1100 din Control Room Ventilation With Filtered Intake & Recirculation ONFIGURATION unlutered inleakage INTAK<E AND RECIRC MNCNRXRO FILTER VOL -V Oto 7Tf. f - 0 02*
v-I~o BM51 2000) Cft tt
1 CRFA - Emergency Mode
"* RBS Has Dual Air Intakes which Can be Manually Selected
"° Utilized "Flow Biased" Setpoints
- Unfiltered Inleakage uses MAI (X/QMAI)
- Filtered Intake uses the Most Favorable X/Q (x/QMF) and Applies a Reduction Factor of 4 for Dual Manual Air Intakes.
"* "Effective" y/Q Determined "Effective" I/Q
=Z 2700cfm1%MF
)+ 00cfmrVoMAI)
XQeffective
-2000cfm
2 Loss of Coolant Accident (LOCA)
"° Performed per RG 1.183, Appendix A
- One exception to RG 1.183
"* Assumed Failure of Emergency Diesel Generator
"* Assumed Failure of Main Steam Isolation Valve
"* Coincident with a Loss of Off-site Power
"* Coincident with a Safe Shutdown Earthquake LOCA - General Assumptions
° Automatic Initiation of Standby Gas Treatment System (SGTS) Not Credited
- Secondary Containment Not Credited for the First 30 Minutes of the Event
- MCR ESF Filters Not Credited for First 20 Minutes of Event
3 LOCA - Source Term
"* Gap and Early In-Vessel Release
" Fuel Releases - 2 Hour Duration
"* Release Fractions per RG 1.183, Table 2
- Iodine Chemical Species
- Aerosol 95%
- Elemental 4.85%
- Organic 0.15%
LOCA - Containment
"* No Containment Sprays.
"* Natural Deposition of Halogens Credited in Drywell Only
- Power's (10) Model
- Elemental Removal Constant, X = 1.01 hr1
"* No Suppression Pool Scrubbing Credited
"* Release Rated Reduced by 45% at 24 Hours Based on Containment Pressure
4 LOCA-Containment
"* Blowdown (DW -
Cont.)
-4.74E+5 cfm for 10 minutes
"* Hydrogen Mixing (DW +-o Cont.)
- 600 cfm starting at 25 minutes
"* Steaming Data (DW -- Cont.)
- 3000 cfm starting at 25 minutes
"* Infinite Mixing (DW,-+ Cont.)
- 1 E8 cfm assumed to homogenize DW/Cont.
at 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> LOCA - Releases Primary Containment Leakage (La)
- 0.325% per day (0.179%/day after 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />)
-Assumed from both DW and Cont.
-Assumed Main Plant Stack Release Point 30 Minutes Released to Environment
- >30 Minutes Released to Annulus (SGTS)
5 LOCA - Releases Secondary Containment Bypass
- Independent of La I
- Released Directly to Environment via Turbine Building
- 580,000 cc/hr @ Pa (319,000 > 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />)
- Released from Containment Node
- MSIV Failure
- 50 scfh
- MS-PLCS Operational @ 25 minutes
- Released from Drywell LOCA - Releases Engineered Safety Feature (ESF) Liquid Leakage
-Assumed 1 gpm
- 0 - 30 Minutes Released to Environment
- >30 Minutes Released to Aux. Bldg. (SGTS)
- 10% Flashing Fraction
- Only deviation from RG 1.183 guidance
1 LOCA Results Contributor EAB LPZ MCR Cont./Sec. Cont.
2.6 1.7 0.4 SCB/MSIV 12.3 5.4 2.9 ESF
<0.1 0.4
<0.1 Total 15.0 7.5 3.4 Reg. Limit 25.0 25.0 5.0 Fuel Handling Accident (FHA)
- Performed i.a.w. Reg. Guide 1.183, Appendix B
- Assumed 150 GE 9x9 Rods Damaged
-Actual calculated is 122 9x9 Rods
- 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> Decay Time
- 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> Release
- Radial Peaking Factor (RPF) = 2.0
2 FHA - Assumptions
"* Halogen Decontamination Factor of 200
"* No MCR ESF Filters Credited
- Credit Taken for Dual Intakes
"* Containment Release Point Assumed
- "Old" Dispersion Factors Used
-Values Used Bound Those Calculated Using ARCON96 FHA - Light Load Accident (LLA)
- Bounding Scenario is Light Load Drop from Polar Crane onto Reactor Core
- 300 GE 9x9 Rods
-Actual calculated was 247 9x9 rods
- All Other Assumptions Identical to FHA
3 FHA/LLA - Results (REM TEDE)
Location FHA LLA Regulatory Limit EAB 2.5 5.0 6.3 LPZ 0.4 0.7 6.3 MCR 1.7 3.3 5.0 Control Rod Drop Accident (CRDA)
"* Two Cases Analyzed
- Design Basis Case (Full Power Event) 0 Regulatory Guide 1.183, Appendix C Assumptions
- Lower Power Event
- Limited CRDA with Condenser Mechanical Vacuum Pumps in Operation
"° x/Q Based on Turbine Building Release
4 CRDA Design Basis Event
- 850 GE 8x8 Rods (13.7 Assemblies)
- RPF = 2.0
- Assumed 100% Fuel Melt
- Fuel Melt Release Fractions - RG 1.183, Appendix C
- 100% Noble Gases
- 50% lodines CRDA Design Basis Event
" Plateout Consistent with RG 1.183, Appendix C Assumptions
- Sections 3.3 and 3.4
"* Condenser Release Rate = 1 % per day
"* Condenser Iodine Chemical Fractions
- 97% Elemental/3% Organic
"° No Credit for MCR ESF Filters
5 CRDA-Limited CRDA
"* Control Rod Drop (or other reactivity event) which has Limited Fuel Damage
"* Assumptions Consistent with GE NEDO 31,400A
"* Plant Mechanical Vacuum Pumps are Assumed to be Operating CRDA - Limited CRDA
- 10 Second "Burst" Release
- 30 R/hr including instrument uncertainty
- Assumed Cladding Damage Only
- Gap Release Fractions per RG 1.183, Appendix C
"* Steam Dome Volume of 1.79E8 cc Used to Determine Steam Concentrations
"* RPF = 2.0
"* Determine 50 Rods Damaged for 30 RPhr
-Neglects N-16 Background Radiation
"* Plateout Consistent with RG 1.183, Appendix C Assumptions CRDA - Limited CRDA
"* Release Rates
- 4,000 cfm through MVP for first 20 minutes
- 1% per day for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />
"* Condenser Iodine Chemical Fractions
- 97% Elemental/3% Organic
"* MCR ESF Filters Manually Initiated at 20 Minutes
- Flow Biased X/Q (Consistent with LOCA)
Low Receptor Regulatory Power Power Limit Event Event EAB 6.3 0.9 4.7 LPZ 6.3 0.4 0.5 MCR 5.0 0.5 1.3 Main Steam Line Break (MSLB)
"* Regulatory Guide 1.183, Appendix D
"* No Fuel Damage due to MSIV Closure
- Main Steam Blowout Panel Release Point
- No Credit for CRFA ESF Filters
- 5.5 Second Release (MSIV Closure Time)
8 MSLB Assumptions
- Mass Release Based on Original Plant Licensing Conditions
- 11,620 Ibm of steam released
- 68,942 Ibm of coolant released
- 100% of Activity Released
- Two Cases Analyzed
- Equilibrium Iodine - 0.2 uCi/gm
- Iodine Spike - 4.0 uCi/gm MSLB - Results
- Off-Site Doses
- Equilibrium Iodine Case
"* EAB & LPZ - <0.1 REM TEDE (2.5 REM)
- Iodine Spike Case
"* EAB - 1.4 REM TEDE (25 REM)
"* LPZ - 0.2 REM TEDE (25 REM)
- Main Control Room Doses
- Iodine Spike Case Bounding - 2.2 REM
.9 Conclusions
" AST methodology was applied per NRC regulations and guidance with significant conservatisms and margins.
"* Dose consequences of postulated DBA analyses are within NRC guidance limits.
"* The revised analyses demonstrate that certain TS limits and LCOs may be changed without compromising safety.
Discussion