ML20197A499
| ML20197A499 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 12/08/1997 |
| From: | Janecke R, Kalache M, Swartz E COMMONWEALTH EDISON CO. |
| To: | |
| Shared Package | |
| ML20197A489 | List: |
| References | |
| L-001378, L-001378-R01, L-1378, L-1378-R1, NUDOCS 9712230074 | |
| Download: ML20197A499 (6) | |
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Attachment 1
Calculation L-001378, Revision 1, " Calculated Probability for Sustained Bolling in the LaSalle Fuel Pools," dated December 8,1997 i
1 971223007k05000373 971216 PDR ADOC P
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t NUCLEAR FUEL SERVICES DEPA%TMENT NUCLEAR DESIGN INFORMATION TRAN$MITTAL 0 SAFETY RELATED Ongnetang Organizeten NDIT No.
970201 01
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S NON SAFEW RELATED E Nuclew Fuel Servces Rev. No.
C O REGULATORY O othw(spoosfy)
Page i of 1 l
RELAT F.D Staten LaSalle und Al Cycle Al Generc To D Henry, LaSalle Staton System Engeeereg Sutged Tre ematelof Calculaten No L.001370 Rev 1 Mots.t F Janecek M24we
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_hlad Kalache Date Revwwer Revwwer's Signature
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-1 NF S Supervisor NFS f W Date Status of information S Verded O urwweed O Enge=wes Juegement Method and Schedule of Verifcohon for Unvenhed NDITs.
Desc* ion of informate". Upgrade of NDIT 970201 to include docussen of probatanty of tolinpa 18 hours2.083333e-4 days <br />0.005 hours <br />2.97619e-5 weeks <br />6.849e-6 months <br /> wth fuel pools not connected.
Purpose of informaten Asset en tha tesponse to the NRC Fenni Report on Spent Fuel Storage Pool Safety issues.
aource of informaton. NFS PSA Group CalcVM A Supplemental Distabuhon e
1
Calcul: tion Titl3 Page CALCULATION TITLE PAGE Calculation No: L-001378 DESCRIPTION CODE: N00 DISCIPLINE CODE:_ N SYSTEM CODE: P LASALLE STATION TITLE:
Calculated probability for sustained boilina in the laSalle fuel pools, Safety Related Augmented Quality X
Non Safety Related REFERENCE NUMBERS Type Number Type Number COMPONENT EPN:
DOCUMENT NUMBERS:
EPN Compt Type Doc Type / Subtype Document Number CALC / ENG L-001378 REMARKS:
REV.
REVISING APPROVED DATE O.
ORGANIZATION PRINT / SIGN b/06/97 0
NFS/PSA E. D. Swartz p,,
g,,
8dM(([
N//,/pp 1
NFS/PSA E. D. Swartz
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Controlled Electronic Form Page 1 of 2 File 12-02c doc See NEP Table of Contents issued 9/23/97 NEP.12 02C
Revision Summaries CALCULATION NO. L-001378 PAGE NO.: 2 REVISION SUMMARIES REV: 0 REVISION
SUMMARY
Original Calculation Electronic Caiculation Data Files:
(Progrem Name. Verson, F Ae name eWure/ dad 6 Mal. trun)
None 10/30/97 Prepared by: R. F. Janecek Print / Sign Date 11/06/97 Reviewed by: M R. Kalache Print /Slan Date Type of Review f ] Test
[ X ] Detailed
[ ] Alternate DO ANY ASSUMPDONS IN THIS CALCULATICN REQUIRE l.ATER VERIFCABON
[ ] YES [X]to Tracked by:_ N/A u
REV: 1 REVISION
SUMMARY
Calculation revised to include the probability of sustained boiling in 18 hours2.083333e-4 days <br />0.005 hours <br />2.97619e-5 weeks <br />6.849e-6 months <br />, with tile pool not :.onnected.
Electronic Calculation Data Files:
(Program Name, Version, file name ent/stro/datehimal. min)
None Prepared by: R. F. Janecek /dks7Lu/
n/vh 7 Pfint/Si
/
Date Reviewed by:,NI R. Kalache/s t b
rIO
/ 2 -y _.4 7 Pdnt/Sio'n Dete Type of Review
[X] Detailed
[ ] Alternate
[ ] Test DO ANY ASSUMPDONS IN THS CALCULATION REQUIRE 1.ATER VERIFCATION
[ ] YES [X] NO Tracked by: N/A Fde.12-02c doc Controlled Electronic Form Page 2 of 2 lasued 9/23/97 See NEP Tab!e of Contents NEP 12-0:C
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PAGE N?. 3 CALCULATION NO, L 001378 REV.1
1.0 'PURPOSElOBJECTIVE
The purpose of this calculation is to evaluate the probability of sustained be, ting m the fuel pool (s) for thi following scenario:
1 Dual Unit Loss of Offsite Power (DLOOP)
Suf 0cient heat load in the fuel pool (s) to causo sustained bolling.
\\
2.0 METHODOLOGY AND ACCEPTANCE CRITERIA The scenario assumes A Dual Unit Loss of 0" site Poser (DLOOP) at a point in time when sufficient heat i'
load exists in either fuel pool to result in susta ad boiling due to loss of fuel pool cooling caused by the DLOOP.
This analysis will calculate the picbability for sustained boiling to occur wing data and methodology from the LaSalto PSA model.
A probability of less than 1.0E 06 is considered to be Nort-risk Significant.
3.0 ASSUMPTIONS None.
4.0 DESIGN INPUTS 4.1 LaSalle 1996 PSA model. (Reference 5.1) 4.2 Dresden PSA Model Calculation Note (Reference 5.4)
5.0 REFERENCES
5.1 LaSalle 1996 PSA Model 5.2 November 18,1996 letter from John B. Hosmer to the U. S. Nuclear Regulatory Commission.
- Response to NRC Final Report on Spent Fuel Storage Pool Safety issues.'
5.3 PSA Applica18tns Guide, EPRI TR 105396, August 1995.
5.4 Dresden Calculation Note Number DR CN 92 006, Rev. O, dated 1/18/93.
6.0 CALCULATIONS C.1 From Reference 5.1, the frequency for a DLOOP initiating event in 1.6E 02.
From Reference 5.2, the time that either unit will have sufficient heat load in the fuel pool (fresh discharge) is approximately 1/10 of a year. For two units, then, the time would be twice this value, or 2.0E 01 years, Also from Reference 5.2, the time for the connected pools to boilis at leaet 25 hours2.893519e-4 days <br />0.00694 hours <br />4.133598e-5 weeks <br />9.5125e-6 months <br />. If the pools are not connected, the time to boil is at least 18 hours2.083333e-4 days <br />0.005 hours <br />2.97619e-5 weeks <br />6.849e-6 months <br />. If offsite power can be restored b9 fore these times, then sustained boiling can be avoided. No specific value for falling to restore offsite power in either 18 or 25 hours2.893519e-4 days <br />0.00694 hours <br />4.133598e-5 weeks <br />9.5125e-6 months <br /> was used in the LaSalle PSA model(Reference 5.1).
However, a value for the probability for failing to restore offsite power in 24 hot ts,2.47E 03, was calculated and this value will be used for the 25 hour2.893519e-4 days <br />0.00694 hours <br />4.133598e-5 weeks <br />9.5125e-6 months <br /> calculation. A value for failing to restore otrsite power in 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br />. 5.92E-03. was calculated for the DreMen PSA model (Reference 5.4).
CALCULATION NO. L 001378, REV.1 PA"E NO. 4 Since the Dresden and LaSalle models used 6dentical methodology, this value O applicable and is conservative for the 18 hour2.083333e-4 days <br />0.005 hours <br />2.97619e-5 weeks <br />6.849e-6 months <br /> calculati:n.
A procedure to tie the RHR system to the fuel pool to provide cooling is already in place. At least 18 hours2.083333e-4 days <br />0.005 hours <br />2.97619e-5 weeks <br />6.849e-6 months <br /> are available to perform the existing procedure (25 hours2.893519e-4 days <br />0.00694 hours <br />4.133598e-5 weeks <br />9.5125e-6 months <br /> if the pools are connected). Therefore, thn failure probability for the operator to perform the actions to restore cooling to the pool is conservatively assumed to be 1E 02 (Reference 5.2, Zion response).
62 The probability, then, for sustained boiling in the fuel pool (s), Pa. is the product of all four factors:
Pan (Frequency) * (Time) * (Feiture to Recover Offsite Power) * (Operator Action Failure)
For 25 hours2.893519e-4 days <br />0.00694 hours <br />4.133598e-5 weeks <br />9.5125e-6 months <br />.
Pan = (1.6E 02) * (2.0E 01) * (2.47E 03) * (1E 02)
Pen = 8 E 08 For 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br />, Pois = (1.6E 02) * (2.0E 01) * (5.925 03) * (IE 02)
Paie = 2 E 07 7,0
SUMMARY
, CONCLUSIONS, RECOMMENDATIONS The probability of a DLOOP occuriing while significant heat load exists in the pool (s)is small. The probability of f ailing to recover / restore power or altemate cooling methods is small. The resultant probabilities for sustained pool boiling (2 E 07 and 8 E 08) are quite small, compared to the acceptance criteria for Non-Risk Significance (1.0 E 06).
8.0 LIST OF ATTACHMENTS None.