ML20056F180
| ML20056F180 | |
| Person / Time | |
|---|---|
| Issue date: | 07/26/1993 |
| From: | Thadani A Office of Nuclear Reactor Regulation |
| To: | Rasin W NUCLEAR ENERGY INSTITUTE (FORMERLY NUCLEAR MGMT & |
| References | |
| NUDOCS 9308260154 | |
| Download: ML20056F180 (3) | |
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UNITED STATES 7;i
- j" i NUCLEAR REGULATORY COMMISSION 4...../
WASmNGTON. D.C. 2554m JUL 2 61933 l
Mr. William H. Rasin Director, Technical Division Nuclear Management and Resources Council 1776 Eye Street, N.W.
Suite 300 Washington, DC 20006-2496 l
l
SUBJECT:
CLARIFICATION ON EPRI FINAL REPORT, TR-100370, FIRE-INDUCED I
VULNERABILITY EVALUATION (FIVE), APRIL 1992
Reference:
Letter from A. Thadani of NRC to W. Rasin of NUMARC, dated-August 21, 1991,
Subject:
"NRC's Staff Evaluation Report on Revised NUMARC/EPRI Fire Vulnerability Evaluation (FIVE) Methodology".
i
Dear Mr. Rasin:
In the Staff Evaluation Report, attached to the above referenced letter, the i
staff concluded that the FIVE methodology is acceptable for use in the IPEEE, provided that a number of specific enhancements be incorporated into the final FIVE report (EPRI TR-100370). With regard to one of these enhancements we i
i note that there is an apparent inconsistency in application of the definition of a fire initiating event throughout the document. Although the EPRI t
document defines a fire initiating event (EPRI TR-100370, page.2-2) somewhat differently than the definition recommended by the staff in the above referenced letter, the staff considers the definition consistent with ours.
In reviewing the final FIVE document, however, the staff identified a figure
.I and three places in the text which sugfst that fire areas could be screened out simply based on the absence of Appendix R shutdown. equipment in a particular fire area. We believe this inconsistency could potentially narrow the focus of the fire analysis.
The enclosure provides our suggested revisions. We expect that licensees will. perform a broad fire analysis consistent with both EPRI's fire initiating event definition specified on i
page 2-2 in the FIVE document, and our earlier letter to you. Therefore, we request that the FIVE document be clarified in order to prevent any confusion with respect to the implementation of the FIVE methodology.
o,
I-a j
3 William H. Rasin,
i' If you have any questions, please contact John T. Chen, IPEEE program manager, at 301-492-3919.
ORIGINAL SIGNED BY A.C.THADANI Ashok C. Thadani, Director Division of Systems safety and Analysis Office of Nuclear Reactor Regulation
Enclosure:
As stated cc:
J. Sursock, EPRI DISTRIBUTION:
l JTaylor TMurley EBeckjord l'
TSpeis WRussell WMinners LShao FGillespie TKing CAder CMcCracken SWest IMiller WBeckner JChen JFlack AEl-Bassioni GKelly PMadden RES Circ /Chron SAIB R/F DSIR C/F
- PDR
ACRS i
- See previous concurrence OFFC: DSIR/SAIB : DSIR/SAIB: DSIR/SAIB: DD/DSIR : D/DSIR NAME: JChen/bgj*: JFlack*
- CAder*
- JMurphy*: WMinners*:
DATE: 6/24/93
- 6/23/93
- 6/2 3 : 7/1/93 7/2/93 n
NRRhN: NRRWDh :
0FFC:
NRR NAME: CMcCracken: WBec,ner: AThadpni:
DATE: ') [JJ/93 1/p, '}$:
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filename [G:\\ THERM 0LA\\FIVE. NC]
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1 Enclosure The definition of fire initiating event as stated in the final FIVE report (Page 2-2) is not exactly the same, words by words, as that recommended in the j
Staff Evaluation Report. Nevertheless, the staff considers that definition, more or less, is consistent with what was recommended by the staff, "a fire-initiating event should be defined as a fire in any area that results in a
]
demand for safe shutdown functions or disables equipment important to plant 1
shutdown capability or the ability to mitigate the consequences of an J
accident", therefore, it is acceptable. However, the staff has noticed that the fire initiating event has not being treated consistently throughout the document, and recommends that the following areas be clarified in order to prevent any confusion with respect to this matter.
1.
Introduction (Page 5-1 of the final FIVE report)
The third paragraph should be revised to read as follows:
l The project team determines if this fire initiated event has the potential to result in a demand for safe shutdown functions (...) or damage safe shutdown components in the fire areas.
If not, the fire area can be screened out.
l 2.
Phase I Procedures (Page 5-3 of the final FIVE report) l The second paragraph should be revised to read as follows:
l t
A fire area can not be screened out from further evaluation if:
1.
There are Appendix R safe-shutdown components in the area.
[
OR 2.
Following a fire event in a area, there is a demand for l
safe-shutdown functions because the plant can not maintain normal plant operation.
l 3.
Step 4: Perform Fire Area vs. Safe Shutdown System Screen (Page 5-5 of the final FIVE report) i The evaluation steps should be modified as follows:
2.
After reviewing Table IA, if-the fire areas have no safe i
shutdown equipment and the fire does not demand for plant l
safe shutdown, then the fire areas can be screened out.
4.
Figure 5.1 Phase I Qualitative. Analysis The figure should be made consistent with the staff's original recommendation and the above changes.
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