ML18038B439
| ML18038B439 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 09/28/1995 |
| From: | Salas P TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9510020191 | |
| Download: ML18038B439 (9) | |
Text
PRIORI TY 1 (ACCELERATED RIDS PROCESSING)
REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)
ACCESSION NBR:9510020191 DOC.DATE: 95/09/28
. NOTARIZED: NO DOCKET FACIL:50-259 Browns Ferry Nuclear Power Station, Unit 1, Tennessee 05000259 50-260 Browns Ferry Nuclear Power Station, Unit 2, Tennessee 05000260 50-296 Browns Ferry Nuclear Power Station, Unit 3, Tennessee 05000296 R
AUTH.NAME AUTHOR AFFILIATION SALAS,P.
Tennessee Valley Authority RECIP NAME RECIPIENT AFFILIATION I
Document Control Branch (Document Control Desk)
SUBJECT:
Provides supplemental info re program for assuring seismic adequacy of flexible conduit in response to verbal request from NRC.
DISTRIBUTION CODE:
D030D COPIES RECEIVED:LTR $ ENCLf SIZE: +
TITLE: TVA Facilities Routine Correspondence NOTES RECIPIENT ID CODE/NAME PD2-3 WILLIAMS,J.
INTERNAL: ACRS NRR/DSSA RES/DE/SSEB/SES EXTERNAL: NOAC COPIES LTTR ENCL 1
1 1
1.
6 6
1 1
1 1
1 1
RECIPIENT ID CODE/NAME PD2-3-PD FILE=GENZZR 0 1 OGC/HDS3 NRC PDR COPIES LTTR ENCL 1
1 1
1 1
0 1
1 D
N NOTE TO ALL "RZDS" RECIPIENTS:
PLEASE HELP US TO REDUCE WASTE!
CONTACT THE DOCUMENT CONTROL
- DESK, ROOM OWFN 5D8 (415-2083)
TO ELIMINATE YOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!
TOTAL NUMBER OF COPIES REQUIRED:
LTTR 15 ENCL 14
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Tennessee Valley Authority, Post Office Box 2000. Decatur. Alabama 35609 September 28, 1995 U.S. Nuclear Regulatory Commission ATTN:
Document Control Desk Washington, D.C.
20555 Gentlemen:
In the Matter of Tennessee Valley Authority Docket Nos.
50-259 50-260 50-296 BROWNS FERRY NUCLEAR PLANT (BFN)
UNITS 1I 2
AND 3 SEISMIC ADEQUACY OF FLEXIBLE CONDUITS This letter provides supplemental information regarding the program for assuring the seismic adequacy of flexible conduit in response to a verbal request from the NRC Staff, TVA has identified flexible conduits being routed between the diesel generator and reactor building structures.
These flexible conduit runs contain sufficient slack to accommodate the postulated seismic movements.
The background of this issue and additional details regarding the program for assuring the seismic adequacy of flexible conduit is provided in the enclosure.
There are no new commitments contained in this letter.
Xf you have any questions, please contact me at (205) 729-2636.
Sincerely, Salas Manager of Site Licensing Enclosure cc:
see page 2
9510020191 950'st28 PDR ADOCK'5000259 P,
U.S. Nuclear Regulatory Commission Page 2
September 28, 1995 cc (Enclosure):
Mr. Stewart D. Ebneter Regional Administrator U.S. Nuclear Regulatory Commission Region II 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 Mr. Mark S. Lesser, Acting Branch Chief U.S. Nuclear Regulatory Commission Region II 101 Marietta Street, NW, Suite-2900 Atlanta, Georgia 30323 NRC Resident Inspector Browns Ferry Nuclear Plant 10833 Shaw Road
- Athens, Alabama 35611 Mr. J.
F. Williams, Project Manager U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852
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ENCLOSURE TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)
UNITS 1i 2 AND 3 SEISMIC ADEQUACY OF FLEXIBLE CONDUITS BACKGROUND BFN was initially constructed using General Construction Specification G-3, "Installing Electrical Conduit Systems and Fabricated Conduit Boxes."
This specification required that flexible conduit be provided for electrical connections to equipment (such as motors, valves, lighting fixtures), but contained no specific requirement for minimum lengths for seismic and thermal movements.
TVA subsequently recognized the need for flexible conduit length requirements to ensure adequate thermal movements and revised General Construction Specification G-40, "Installing Electrical Conduit Systems and Conduit Boxes," in October of 1980.
- However, G-40 was not made applicable to BFN until January 15, 1986.
The overall program that resolved the flexible conduit issue for BFN Unit 2 was described in Volume 3 of TVA's Nuclear Performance Plan (Reference 1).
Programmatic details were provided in References 2 and 3.
For the restart of Unit 2, TVA committed to inspect all flexible conduits attached to electrical equipment covered by 10 CFR 50.49.
These inspections verified that the lengths of the flexible 'conduits were adequate to accommodate thermal and seismic movement.
Those flexible conduits not meeting the requirements of G-40 were reworked,
- replaced, or technically justified on a case by case basis.
TVA also committed to evaluate other flexible conduit attached to safety related equipment (other than 10 CFR 50.49 electrical equipment) within the scope of BFN's program to address Unresolved Safety Issue (USI) A-46.
NRC acceptance of this program was included as part of Reference 4.
In Reference 5,
TVA stated that the flexible conduit program would be implemented on Units 1 and 3 in accordance with the Unit 2 precedent.
In Reference 6,
TVA provided a schedule for flexible conduits associated with the resolution of USI A-46.
NRC requested additional information regarding the schedule in Reference 7.
In Reference 8,
TVA clarified the two-phased approach for resolving flexible conduit concerns.
Flexible conduits attached to electrical equipment covered by 10 CFR 50.49 would be resolved prior to restart of Unit 3.
Seismic qualification of flexible conduit, other than those connected to electrical equipment covered by 10 CFR 50.49 (i.e., important to safety, but in a mild environment),
would be included as part of the resolution of
C
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+I In Reference 9,
NRC found this program acceptable;
- however, additional information was requested regarding two separate issues regarding flexible conduit.
TVA provided the requested information in Reference 10.
SUPPLEMENTAL INFORMATION TVA has identified flexible conduits being routed between the diesel generator and reactor building structures.
The maximum seismic deflection between the reactor and diesel generator buildings is 0.385 inches.
The installation drawing specifies that the flexible conduit shall not be in tension when it is installed.
Due to the length of the cable, the requirement not to install the flexible conduit in tension, and the relatively small maximum deflection between the structures, TVA has determined that these flexible conduit runs contain sufficient slack to accommodate the postulated seismic movements.
REFERENCES 1 ~
TVA letter to NRC, dated October 24,
- 1988, Browns Ferry Nuclear Plant Nuclear Performance
- Plan, Revision 2
2 ~
TVA letter to NRC, dated August 18, 1989, Flexible Conduit Program Plan 3 ~
TVA letter to NRC, dated March 2,
- 1990,
Response
to Request for Additional Information Flexible Conduit Letter Dated December 19, 1989 4 ~
NRC letter to TVA, dated January 23,
- 1991, NUREG-1232, Volume 3, Supplement 2
Browns Ferry, Unit 2 5.
TVA letter to NRC, dated July 10, 1991, Regulatory Framework for the Restart of Units 1 and 3
6.
TVA letter to NRC, dated September 21,
- 1992, Supplement 1 to Generic Letter 87-02, Verification of Seismic Adequacy of Mechanical and Electrical Equipment in Operating Reactors, Unresolved Safety Issue (USI) A-46 and Supplement 4 to Generic Letter 88-20, Individual Plant Examination of External Events (IPEEE) for Severe, Accident Vulnerabilities 7.
NRC letter to TVA, dated November 19,
- 1992, Generic Letter 87-02, Supplement 1 Response Browns Ferry Nuclear Plant '
TVA letter to NRC, dated January 19,
- 1993, Generic Letter (GL) 87-02, Supplement 1,
120-Day Response, Request for Additional Information NRC letter to TVA, dated March 19,
- 1993, Generic Letter 87-02, Supplement 1 Response Browns Ferry Nuclear Plant TVA letter to NRC, dated October 15,
- 1993, Generic Letter (GL) 87-02, Supplement 1, Verification of Seismic Adequacy of Mechanical and Electrical Equipment in Operating
- Reactors, Unresolved Safety Issue (USI) A-46 Response to Request for Additional Information Regarding the Evaluation of the Seismic Adequacy of Flexible Conduit El-3