RC-97-0050, Clarifies Info Provided to NRC in Util Previous Responses to GL 92-08

Clarifies Info Provided to NRC in Util Previous Responses to GL 92-08

ML20140B944
Person / Time
Site:	Summer
Issue date:	03/27/1997
From:	Gabe Taylor SOUTH CAROLINA ELECTRIC & GAS CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GL-92-08, GL-92-8, RC-97-0050, RC-97-50, NUDOCS 9704010538
Download: ML20140B944 (4)

Text

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- South Car: lina Electric & C:s Company Gary J. Taylor i P.o. Box 88 Vio) Przsident Jenkinsville. SC 29065 Nuclear operations

. (803) 345-4344 gg l ABCanniClumely March 27, 1997

RC-97-0050 i i Document Control Desk

} U. S. Nuclear Regulatory Commission Washington, DC 20555 l

tl ' Gentlemen:

Subject:

VIRGIL C. SUMMER NUCLEAR STATION l DOCKET NO. 50/395  !

! OPERATING LICENSE NO. NPF-12 ,

4 FOLLOW UP TO THE REQUEST FOR ADDITIONAL INFORMATION l REGARDING GENERIC LETTER 92-08 AND CONDUlT VUL21 A

l South Carolina Electric & Gas (SCE&G) submits the following information

. pursuant to the NRC's request.

}

j This letter is to clarify information provided to the NRC in SCE&G's previous.

t responses to Generic Letter (GL) 92-08 Requests for Additional information

(RAl) and related staff questions during the telecon on March 4,1997. This i

letter specifically addresses the NRC Staff's questions and SCE&G's position l regarding Conduit VUL21 A and GL 92-08. In addition, an update on SCE&G's 1

schedule as submitted in SCE&G's previous RAI response dated March 23, .

1995 is provided.

i

) As identified in SCE&G's letters to NRC dated 9/15/92,2/22/93,2/11/94, j 12/23/94,3/23/95, and 6/20/96, Conduit VUL21 A is protected with Thermo-Lag i 330-1 to maintain swing component ("C" Train) capability for the Chiller System.

j As such, the Thermo-Lag Barrier provided for conduit VUL21 A is not within the i

scope of, or required for, compliance with Generic Letter 92-08, Appendix R to l 10 CFR Part 50, or Regulatory Guide 1.75.

2 Generic Letter 92-08 identifies the " Area of Concern" to be barriers that are l installed to meet the requirements of Section 50.48, " Fire Protection"; General Design Criterion (GDC) 3, " Fire Protection", of Appendix A; or " General Design Criteria for Nuclear Power Plants" to 10 CFR Part 50. In general, these requirement and guidance documents apply to fire protection features which are installed to maintain one train of safe shutdown systems free of fire damage. ,

. The A and B Train Chiller Systems conform to the requirements of Appendix R to 10 CFR Part 50.

~

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1555555.U.5M

Document Control Desk LTR 920008

" RC-97-0050

' Page 2 of 3 SCE&G's letters to NRC dated 3/23/95 and 6/20/96 (RC-96-0158), identify that SCE&G will modify the Thermo-Lag protection provided for Conduit VUL21 A. As stated in SCE&G's 6/20/96 letter (RC-96-0158), "SCE&G plans to resolve the Thermo-Lag 330-1 issue for Conduit VUL21 A pursuant to internal policies for maintaining 'C' Train equipment." This modification will remove the Thermo-Lag material and construct a fire rated gypsum board enclosure around the conduit. .

The design inputs or considerations used in the development of the modification l package (s) are consistent with typical modifications performed on or having the  :

potential to affect Nuclear Safety Related components. A brief description of the  !

enclosure is provided below:

The new enclosure will consist of two existing 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> fire rated concrete  :

walls (south and east) and two new 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> fire rated gypsum board walls >

(north and west). The existing concrete floor is 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> fire rated. A new 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> fire rated gypsum board ceiling will be installed to complete the )

enclosure. All penetrations into the enclosure will be sealed in a manner  ;

to maintain the fire ratings identified above. The construction of the i enclosure will be similar to accepted UL listed designs. Minor variations from the UL Listed designs will be evaluated (similarity analysis) to ensure the listed fire rating is maintained. A design calculation has been I performed which evaluates and concludes that no long term cable degradation issues related to Thermo-Lag ampacity has occurred for the l

cables in Conduit VUL21 A. The results of this calculation indicate that the cables in Conduit VUL21 A have in excess of 170% ampacity margin.

In addition, a similarity analysis (calculation) is being performed to ensure adequate ampacity is available in the existing VUL21 A cables with the new enclosure installed. Considering the relatively high ampacity margin available, SCE&G does not anticipate ampacity to be a significant design issue.

In summary, the Thermo-Lag 330-1 fire barrier protection that is provided for Conduit VUL21 A is not installed to meet regulatory requirement or guidance documents. This barrier is installed to provide operational flexibility (margin) in the unlikely event a fire occurs. SCE&G intends to maintain this "C" Train operational flexibility through removal of the Thermo-Lag barrier and installation of a 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> fire rated gypsum board enclosure that, while not required, technically complies with regulatory requirements for safe shutdown equipment necessary to meet Appendix R to 10 CFR Part 50.

SCE&G is on schedule in completing activities associated with resolution of the Thermo-Lag issue at Virgil C. Summer Nuclear Station. As indicated during our March 4,1997 telecon, SCE&G intends to begin implementation of the '

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. Docum::nt Control Desk I LTR 920008

' RC-97-0050

' Page 3 of 3 l

associated modifications within the next couple of months. Allimplementation i activities will be completed during the Refueling Outage scheduled for later this year. Per the schedule provided to NRC, SCE&G's Thermo-Lag Resolution  ;

effort will be complete by the end of November 1997. As discussed during the  ;

March 4,1997 telecon, SCE&G anticipates receipt of the SER(s) for the l Deviation Requests for Conduit XX-7177A and Cable Tray 3088 on or before j September 15,1997 (Reference Deviation Requests submitted with SCE&G letter dated October 17,1996). In the interim, any NRC Staff questions or requests for additional information relative to the Deviations will be handled expeditiously by SCE&G to support the Staff's review effort and ensurs SCE&G's I resolution schedule is maintained.

I declare that the above statements and matters set forth herein are true and I correct to the best of my knowledge, information, and belief.

l Should you have any questions, please call April Rice at (803) 345-4232 or Linda Martin at (803) 345-4217.

Sincerely, b

)#

Gary J. Taylor MSB/LJM/GJT c: J. L. Skolds NRC Resident Inspector W. F. Conway J. B. Knotts, Jr.

R. R. Mahan NSRC R. J. White RTS (LTR 920008)

L.A.Reyes File (815.14)

A. R. Johnson DMS (RC-97-0050)

I K. R. Jackson General Managers"

i

. ' Nct:riz tion of Document Control Desk

'~' ~LTR 920008 RC-97-0050 STATE OF SOUTH CAROLINA  :

TO WIT : 1 COUNTY OF FAIRFIELD  :

I hereby certify that on the 27 O da of #/ml 19 97. before me, the subscriber, a Notary Public of the State of South darolina personally appeared Gary J. Taylor, being duly sworn, and states that he is Vice President, Nuclear Operations of the South j Carolina Electric & Gas Company, a corporation of the State of South Carolina, that he '

provides the foregoing response for the purposes theroin set forth, that the statements ,

made are true and correct to the best of his knowledge, information, and belief, and that I he was authorized to provide the response on behalf of said Corporation. j WITNESS my Hand and Notarial Seal  %~

Notdry Public Mybommis ion,' Expires We @3, E

. . . ' ' B' Date

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