ML20128N274

Requests Addl Info on Cable Ampacity Derating Factor Determinations for Plant,Per GL 92-08, Thermo-Lag 330-1 Fire Barriers

ML20128N274
Person / Time
Site:	Davis Besse
Issue date:	10/09/1996
From:	Gundrum L NRC (Affiliation Not Assigned)
To:	Jeffery Wood CENTERIOR ENERGY
References
GL-92-08, GL-92-8, TAC-M85542, NUDOCS 9610160337
Download: ML20128N274 (4)

Text

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- l Octcber 9, 1996 Distribut on w/encls:

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'PUBLIC EAdensam PD3-3 Reading ACRS JRoe OGC JCaldwell, RIII GMarcus Mr. John K. Wood APal RJenkins Vice President - Nuclear, Davis-Besse PGill JCalvo Centerior Service Company l c/o Toledo Edison Company '

Davis.Besse Nuclear Power Station 5501 North State Route 2 Oak Harbor, OH 43449-9760

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION ON CABLE AMPACITY -

DAVIS-BESSE NUCLEAR POWER STATION, UNIT NO. 1 (TAC NO. M85542)

Dear Mr. Wood:

By letter dated June 26, 1996, Davis-Besse Nuclear Power Station (DBNPS) submitted a response to the NRC staff's Request for Additional Information (RAI) dated October 11, 1995, related to Generic Letter (GL) 92-08, "Thermo-Lag 330-1 Fire Barriers." You stated that you intend to remove all existing Thermo-Lag and replace it with an alternate material. Your June 26, 1996, submittal addressed the adequacy of margin to accommodate the ampacity derating resulting from the application of Thermo-Lag from the time it was installed until the time it is removed, such that the insulation properties of the protected cables are not adversely impacted. The NRC staff completed the preliminary review of your original analytical approach as documented in the June 26, 1996, submittal and has identified specific questions that require further clarification and discussion. Enclosed is the staff's request for additional information.

In your letter of June 26, 1996, you requested completion of the review of ampacity issues by December 30, 1996. Please respond to the enclosed request for additional information on ampacity derating factor determinations for DBNPS within 30 days. Should you have any questions or require additional ,

information or an extension of the schedule, please contact Allen G. Hansan, i at (301) 415-1390.

Sincerely, Original signed by:

Linda L. Gundrum, Project Manager g Project Directorate III-3 Division of Reactor Projects III/IV JOT

\y Office of Nuclear Reactor Regulation Docket No. 50-346

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Enclosure:

Request for Additional Information cc w/ encl: See next page NRC FILE CENTER COPY DOCUMENT NAME: G:\DAVISBES\DB85542A.RAI To reenive e espy of this dooumont,indloate in the bec *C" = Copy without encloeures *E* = Copy with enclosures "N" = No copy 0FFICE PDIII-3:LA E PDIII-3:PMl E I l l NAME DFoster-CursRentj LGundrum MS DATE 10/ 4 /96 K 10/q /96 9610160337 961009" '%CIAL RECORD COPY PDR ADOCK 05000346 F PDR

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NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 30666-c001

..... October 9, 1996 Mr. John K. Wood Vice President - Nuclear, Davis-Besse Centerior Service Company c/o Toledo Edison Company 3 Davis-Besse Nuclear Power Station 5501 North State Route 2 Oak Harbor, OH 43449-9760 l

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION ON CABLE AMPACITY -

l DAVIS-BESSE NUCLEAR POWER STATION, UNIT NO. 1 (TAC NO. M85542)

Dear Mr. Wood:

l By letter dated June 26, 1996, Davis-Besse Nuclear Power Station (DBNPS) submitted a response to the NRC staff's Request for Additional Information

! (RAI) dated October 11, 1995, related to Generic Letter (GL) 92-08, "Thermo-Lag 330-1 Fire Barriers." You stated that you intend to remove all existing Thermo-Lag and replace it with an alternate material. Your June 26, 1996, sut,mittal addressed the adequacy of margin to accommodate the ampacity derating resulting from the application of Thermo-Lag from the time it was installed until the time it is removed, such that the insulation properties of 4 the protected cables are not adversely impacted. The NRC staff completed the

preliminary review of your original analytical approach as documented in the June 26, 1996, submittal and has identified specific questions that require

further clarification and discussion. Enclosed is the staff's request for additional information.

In your letter of June 26, 1996, you requested completion of the review of i ampacity issues by December 30, 1996. Please respond to the enclosed request for additional information on ampacity derating factor determinations for i DBNPS within 30 days. Should you have any questions or require additional

information or an extension of the schedule, please contact Allen G. Hansen, 1

at (301) 415-1390.

l Sincerely, dtuno

Linda L. Gundrum, Project Manager 1 i Project Directorate III-3 1 4 Division of Reactor Projects III/IV Office of Nuclear Reactor Regulation Docket No. 50-346

Enclosure:

Request for Additional Information cc w/ encl: See next page i

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] REQUEST FOR ADDITIONAL INFORMATION 1

AMPACITY DERATING ISSUES l

1. You properly identified an additional derating factor to account for multiple conductors within the raceway, if applicable, utilizing the

' appropriate factor provided in the industry standard. However, this derating factor is not applied in actual calculation. If a conduit has

three 1/C #2/0 cable with one #4 ground, the total number of conductors in the conduit is four. According to National Electric Code (NEC) or j

i Insulated Cable Engineers Association (ICEA) Standards, a derating factor of 0.8 shall be used in the ampacity determination. This is not the case as shown in Table 1, "Ampacity Derating due to Thermo-Lag," of the subject l i

calculation. The licensee needs to include total number of conductors in i each conduit and appropriate derating factors in its calculations. The '

j staff believes that the ampacity of cable will be impacted by the number {

j of conductors inside a conduit. Provide justification for this deviation '

i or provide a revised calculation.

2. For cables installed in exposed or enclosed groups of conduits in air, the grouping factors given in Table IX of ICEA Standard P-46-426, " Power Cable i ,

Ampacities, Volume 1, Copper Conductors," shall be used when the spacing l

between conduit surfaces is not greater than the conduit diameter or less

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than 1/4 of the conduit diameter. The calculation did not use conduit i grouping factor. Provide a discussion about the use of the conduit l

?

grouping factor for applicable DBNPS installations.

4 l 3. Conduit fills in percent should be included in the subject calculation.

1 Justification of cable ampacity needs to be provided if the conduit fill

exceeds the value given in NEC tables.

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4. It appears that the licensee used the name plate ampere rating as the load I current. The nameplate ampere is at rated voltage and rated load. This l 1s acceptable provided the loads are not operating at an overload

condition or at a service factor and the rated voltage are maintained at the load terminals. Provide a discussion about the impact of overload

conditions or the service factor of the load and voltage availability at the load terminals on the ampacity derating margins.

5. Explain the technical basis for the margins added as described in Section i

III.C of this calculation. It should be noted that similar ampacity

derating tests for a single enclosure containing multiple conduits vere j submitted by Tennessee Valley Authority for staff review of Watts Bar fire barriers, ENCLOSURE ,

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Mr. John K. Wood Davis-Besse Nuclear Power Station Toledo Edison Company Unit No. I cc:

Mary E. O'Reilly Robert E. Owen, Chief Centerior Energy Corporation Bureau of Radiological Health '

300 Madison Avenue Service Toledo, Ohio 43652 Ohio Department of Health P. O. Box 118 Mr. James L. Freels Columbus, Ohio 43266-0118 Manager - Regulatory Affairs Toledo Edison Company Davis-Besse Nuclear Power Station Attorney General 5501 North State - Route 2 Department of Attorney Oak Harbor, Ohio 43449-9760 30 East Broad Street Columbus, Ohio 43216 Gerald Charnoff, Esq.

Shaw, Pittman, Potts Mr. James W. Harris, Director and Trowbridge Division of Power Generation 2300 N Street, N.W. Ohio Department of Industrial Washington, D.C. 20037 Regulations P. O. Box 825 Regional Administrator Columbus, Ohio 43216 U.S. NRC, Region III 801 Warrenville Road Ohio Environmental Protection Agency Lisle, Illinois 60523-4351 DERR--Compliance Unit ATTN: Zack A. Clayton Mr. Robert B. Borsus P. O. Box 1049 Babcock & Wilcox Columbus, Ohio 43266-0149 Nuclear Power Generation Division 1700 Rockville Pike, Suite 525 State of Ohio Rockville, Maryland 20852 Public Utilities Commission 180 East Broad Street Resident Inspector Columbus, Ohio 43266-0573 U. S. Nuclear Regulatory Commission 5503 N. State Route 2 Mr. James R. Williams Oak Harbor, Ohio 43449 Chief of Staff Ohio Emergency Management Agency Mr. James H. Lash, Plant Manager 2855 West Dublin Granville Road Toledo Edison Company Columbus, Ohio 43235-2206 Davis-Besse Nuclear Power Station 5501 North State Route 2 President, Board of County  !

Oak Harbor, Ohio 43449-9760 Commissioner of Ottawa County  !

Port Clinton, Ohio 43452 I

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