ML17158A214
| ML17158A214 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 04/06/1994 |
| From: | James Shea Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 9404140250 | |
| Download: ML17158A214 (10) | |
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Docket Nos.
50-387 and 50-388 UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 2055&4001 April 6, 1994 LICENSEE:
Pennsylvania Power and Light Company FACILITY:
Susquehanna Steam Electric Station, Units 1 and 2
SUBJECT:
REVIEW OF CALCULATIONS REGARDING LOSS OF SPENT POOL COOLING EVENTS On Harch 15,
- 1994, a meeting was held between Pennsylvania Power and Light Company (PP8L), the licensee for Susquehanna Steam Electric Station (SSES),
Units 1 and 2, and the NRC staff to review certain radiological calculations.
The calculations provide an analysis of the radiological dose that would be received by plant operators performing various activities to mitigate a loss of cooling to the spent fuel pool under loss of coolant accident radiological conditions.
A list of those attending the meeting is attached as Enclosure l.
The meeting was requested by the staff to review the calculational details and assumptions behind the estimated operator doses put forth in various licensee submittals related to a November 27, 1992 report filed pursuant to 10 CFR Part 21, including letters dated Hay 24, 1993, January 4,
1994 and February 2,
1994.
After a statement of the meeting's purpose by the staff, the licensee provided an outline of their dose evaluation activities.
The handout which accompanied this portion of the licensee's presentation is attached as Enclosure 2.
The staff reviewed the licensee's source term assumptions.
The licensee had performed dose calculations using three different source terms for comparative purposes.
The staff reviewed those calculations that assumed a release to primary containment equivalent to that described in Regulatory Guide 1.3.
The staff determined on preliminary review that the source term used was the same as that used in Chapter 15.6.5 of the SSES Final Safety Analysis Report, with the exception of credit taken for transient pressure response of primary containment.
The staff asked for a more thorough description of the pressure decay methodology and flow regime modeling (Hoody, choked, etc) used to modify the assumed leakage out of primary containment.
The staff and licensee discussed the treatment of the contribution of leakage from engineered safeguards feature systems to both airborne and fixed source terms.
The staff sought clarification of the primary containment leakage rates used in the calculations.
The licensee explained that they had performed calculations using several leak rates for comparison purposes.
The I
ensuing discussions addressed justifications for using measured leak rates instead of the constant IX/day value assumed in the Technical Specification; use of as-found versus as-left measured leakage; and justification for crediting the leakage reduction effect of water filled penetrations.
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The staff and licensee discussed the modeling of mixing based on assumed 9404 i40250 94040h PDR ADOCK 05000387 P
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operating modes of the recirculation ventilation system.
The licensee provided a brief description of the compartment modeling and time-motion studies used as input to the HICROSHIELD dose modeling software.
At the close of the meeting, the staff indicated that more time was needed to review the calculations themselves.
The licensee agreed to provide a copy of the initial calculations to the staff with the understanding that the calculations would be returned.
The staff stated that the initial calculations will be reviewed to identify those input parameters and assumptions needed by the staff to perform an independent verification of the adequacy of the licensee's final calculations.
Those representative parameters and assumptions will be documented and docketed with the results of the final calculations by the licensee.
The results of the staff's independent radiological verification and assessment will be documented in a final, overall assessment of the issues raised in the Part 21 report.
The licensee acknowledged and agreed to this use of the calculations.
DISTRIBUTION WRussell FMiraglia LReyes SVarga JCalvo CMiller JShea/RClark HO'Brien OGC ACRS(10) w/Enclosure 1
EJordan HVirgilio
- AThadani, FCongel LCunningham RPedersen
'Lobel VHcCree SLee TD'Angelo
Enclosure:
1.
List of Attendees 2.
Meeting Handout cc w/enclosures:
Licensee and Service List
/s/
Joseph W. Shea, Project Manager Project Directorate I-2 Division of Reactor Projects I/II Office of Nuclear Reactor Regulation 1
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'ISTRIBUTION w/Enclosures 1 and 2
SJones
', Docket File'Hubbard NRC &'ocal PDRs JHayes
.PDI-2 Reading HFleishman
- JWhite, RGN-I GKelly, RGN-I,. LPrividy, RGN-I EWenzi'nger,"
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- Previous concurrence with c ments OFFICE PD!1,3/-
PDI-H PRPB BC
- PDI-2 PD NAME DATE h/6'5B 9
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operating modes of the recirculation ventilation system.
The licensee provided a brief. description of the compartment modeling and time-motion studies used as input to the HICROSHIELD dose modeling software.
At the close of the meeting, the staff indicated that more time was needed to review the calculations themselves.
The licensee agreed to provide a copy of the initial calculations to the staff with the understanding that the calculations would be returned.
The staff stated that the initial calculations will be reviewed to identify those input parameters and assumptions needed by the staff to perform an independent verification of the adequacy of the licensee's final calculations.
Those representative par ameters and assumptions'ill be documented and docketed with the results of the final calculations by the licensee.
The results of the staff's independent radiological verification and assessment will be documented in a final, overall assessment of the issues raised in the Part 21 report.
The licensee acknowledged and agreed to this use of the calculations.
Enclosure:
I.
List of Attendees 2.
Meeting Handout cc w/enclosures:
Licensee and Service List Jo ep W. Shea, Project Hanager Project Directorate I-2 Division of Reactor Projects I/II Office of Nuclear Reactor Regulation
Pennsylvania Power
- 8. Light Company Susquehanna Steam Electric Station, Units 1 5 2 CC:
Jay Silberg, Esq.
- Shaw, Pittman, Potts E Trowbridge 2300 N Street N.W.
Washington, D.C.
20037 Bryan A. Snapp, Esq.
Assistant Corporate Counsel Pennsylvania Power 5 Light Company 2 North Ninth Street Allentown, Pennsylvania 18101 Hr. J.
H. Kenny Licensing Group Supervisor Pennsylvania Power
& Light Company 2 North Ninth Street Allentown, Pennsylvania 18101 Hr. Scott Barber Senior Resident Inspector U. S. Nuclear Regulatory Commission P.O.
Box 35 Berwick, Pennsylvania 18603-0035 Hr. Thomas H. Gerusky, Director Bureau of Radiation Protection Resources Commonwealth of Pennsylvania P. 0.
Box 2063 Harrisburg, Pennsylvania 17120 Hr. Jesse C. Tilton, III Allegheny Elec. Cooperative, Inc.
212 Locust Street P.O.
Box 1266 Harrisburg, Pennsylvania 17108-1266 Regional Administrator, Region I U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, Pennsylvania 19406 Hr. Harold G. Stanley Superintendent of Plant Susquehanna Steam Electric Station Pennsylvania Power and Light Company Box 467 Berwick, Pennsylvania 18603 Hr. Herbert D. Woodeshick Special Office of the President Pennsylvania Power and Light Company Rural Route 1,
Box 1797 Berwick, Pennsylvania 18603 George T. Jones Hanager-Engineering Pennsylvania Power and Light Company 2 North Ninth Street Allentown, Pennsylvania 18101 Robert G.
Byram
'enior Vice President-Nuclear Pennsylvania Power 8 Light Company 2 North Ninth Street Allentown, Pennsylvania 18101 Hr. David A. Lochbaum 80 Tuttle Road
- Watchung, New Jersey 07060 Hr. Donald C. Prevatte 7924 Woodsbluff Run Fogelsville, Pennsylvania 18051
ENCLOSURE 1
SUMMARY
OF ATTENDANCE MEETING BETWEEN PENNSYLVANIA POWER AND LIGHT COMPANY AND THE NRC MARCH 15, 1994 NAME ORGANIZATION l.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
Joseph Shea John J.
Hayes, Jr.
Roger Pedersen Samuel Lee George Hubbard Tony O'Angelo Morton Fleishman Charles Miller Glenn Miller Jim Kenny Terrence Mackay David Matchik David Kostelnik Charles Kolter Phillip Brady NRR/PDI-2 NRR/PRPB NRR/PRPB NRR/SPLB NRR/SPLB NRR/SCSB NRC/OCMKR NRR/PD I-2 PP&L/Nuclear Technology PP&L/Licensing PP&L PP&L PP&L PP&L PP&L
Operator Access Dose Evaluation Outline ENCLOSURE 2
I. Reasons For Performing Operator Access Dose Analysis A. Realistic Evaluation Desired
- 1. Specific Dose Rates For Areas Of Interest Were Not Available.
2.. Dose Analysis Would Require Time-Motion to Be Factored into Individual's Total Mission Dose B. FSAR Section 18 Response to NUREG-0737 Section II.B.2 Plant Shielding Study Dose Rates Judged Not Applicable
- 1. Conservative Evaluation Of Radiation Doses, i.e.
-Radiation Zones Reflect Maximum Contact Dose Rates In a Given Zone, Not General Area Dose Rates
- 2. Airborne Dose Rate Contribution Not Considered.
II. Overview of Operator Access Dose Analysis A. Operator Dose Scenarios Evaluated For Recovery From Fuel Pool Boiling:
1.
ESW Make-Up To Spent Fuel Pool 2.
RHR Fuel Pool Cooling Assist 3.
Restoration of Normal Spent Fuel Pool Cooling - NRC Requested
- 4. Monitor Fuel Pool Water Level - NRC Requested B. Operator Actions For Each Recovery Scenario Identified 1.
Determine Specific Access Areas
- 2. Specific Operator Actions 3.
Ingress/Egress Routes 4.
Operator Travel 5. Stay Times C.
Post-LOCA Radiation Sources Identified 1.
Contained Sources Systems and Associated Piping 2.
Reactor Building Airborne Activityfrom Primary Containment Leakage D. Determine Post-LOCA Radiation Source Terms And Dose Rates Inside Reactor Building 1.
Evaluate Realistic Source Terms - "Clad Damage" a.
1 k Cladding Failure with NVREG-1465 Release Fractions b.
100% Cladding Failure with NUREG-1465 Release Fractions 2.
Evaluate Design Basis (Reg. Guide 1.3 / NUREG 0737)
Source Term - "100% Fuel Melt" 3.
Evaluate Dose Rates from Both Type Source Terms a.
Dose Rates from Contained Sources b.
Dose Rates from Airborne Sources E.
Evaluate Operator Access Doses 1.
Dose from Contained Sources 2.
Dose from Airborne Sources
III. Meth A.
B.
C.
D.
E.
G.
odology Used To Evaluate Operator Access Doses 1 % Clad Damage, 100% Clad Damage, 100% Fuel Melt Realistic Containment Leakage Rate 1.
Pressure Decay Over Time Accounted For 2.
Based On LRT Data 3.. Assumes Airborne Leakage Occurs Through Air Sealed
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Penetrations Only Post-LOCA Radiation Sources 1.
Clad Damage Cases a.
1% Clad Damage /100% Clad Damage
- b. NUREG-1465 Activity Release Fractions c.
SRP 6.5.5 Suppression Pool Scrubbing 2.
100% Fuel Damage Case a.
Reg. Guide 1.3 / NUREG-0737 Core Activity Release Fractions
- b. Airborne - 100% Noble Gases / 25% lodines
- c. Suppression Pool Liquid-50% lodines/
1%
Particulates TACT5 Computer Code Used To determine Compartment Activities
- 1. TACT5 VLV'd for Design Use 2.
FSAR Section 15.6.5 (DBA-LOCAAnalysis) ActivityFlow Path Model
- 3. TACT5 Code Supplies-a.
Reactor Building Airborne ActivityConcentrations
- b. Suppression Pool Liquid ActivityConcentrations MICROSHIELD Computer Code Used to Determine Dose Rates 1.
MICROSHIELD VSV'd for Design Use 2.
Dose Rates From Contained (Piping) Sources 3.
Dose Rates from Airborne Inside Compartments Operator Access Time Motion Study
- 1. Travel Rates - Floor Areas And Stairs
- 2. Valve Operating Times Operator Access Doses 1.
Doses From Airborne ActivityAnd Contained Sources
- 2. Ingress / Egress 5 Operator Stay. Time Doses 3.
Sum of Ingress / Egress and Stay Time Doses Gives Total Mission Dose
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