ML20132G655
| ML20132G655 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 12/20/1996 |
| From: | Hagan J ENTERGY OPERATIONS, INC. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GL-92-08, GL-92-8, GNRO-96-00134, GNRO-96-134, NUDOCS 9612260329 | |
| Download: ML20132G655 (12) | |
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Entergy Operations,Inc.
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PO. Box 756
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Port Gibson, MS 39150 e
Tet 601437 6408 Fax 601437 P795 Joseph J. Hagan Vice Presdent Operations Grand Gulf Nuclear S'ation December 20, 1996 U.S. Nuclear Regulatory Commission
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Document Control Desk Mail Stop Pl-37 Washington, D.C. 20555
Subject:
Grand Gulf Nuclear Station Docket No. 50-416 License No. NPF-29 Response to the Request for J.dditional Information Regarding Generic Letter (GL's 92-08: Thermo-Lag Fire Barriers, dated October 28, 1996 GNRG-96/00134 Gentlemen Generic Letter (GL) 92-08 was issued by the NRC to obtain information needed to verify that Thermo-Lag 330-1 fire barrier systems comply with NRC fire protection requirements for protecting equipment required to achieve and maintain safe shutdown in the event of a fire.
Reporting Requirement Item 2 (c) of GL 92-08 requests information concerning the ampacity dorating of cables enclosed in Thermo-Lag fire I
barriers and the evaluation and application of test results performed to determine the ampacity dorating of Thermo-Lag barriers. GGNS provided preliminary responses to Item 2 (c) by letters dated December 21, 1994 and March 29, 1995, (References 1 and 2] respectively.
The information provided in References 1 and 2 was reviewed by the Staff and determined to be incomplete. As such, by letter dated November 6, 1995
[ Reference 31, the Staf f requested that GGNS submit ampacity derating evaluations, including any applicable test reports for NRC review. The anticipated test procedure or a description of the analytical methodology (including typical calculations) that will be used to determine the ampacity derating parameters for Thermo-Lag fire barriers installed at GGNS was also requested.
DY 9612260329 961220 PDR ADOCK 05000416 j
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GNRO-96/00134 Page 2 of4 By letter dated June 28, 1996 (Reference 4], GGNS provided the response to the November 6, 1995 request, which is considered the completed GGNS response to GL 92-08 Reporting Requirement 2 (c). This submittal included the results of the similarity analysis approach utilized to address resolution of ampacity dorating issues pertaining to GGNS Thermo-Lag fire I
barriers, (References 6 and 7]. The GGNS approach is based on the results of ampacity dorating tests previously reviewed by the Staff.
Following completion of the Staff's preliminary review of the GGNS June 28, 1996 submittal, the Staff identified additional questions requiring clarification as delineated in the October 28, 1996 Request for Additional Information (Reference 5]. Attachment 1 to this submittal documents the GGNS responses to the questions identified.
'This information is being submitted under affirmation in accordance with j
10 CFR 50.54 (f) (Attachment 2).
Please contact Charles E. Brooks at (601) 437-6555 should you have any
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questions, or require additional information.
Your truly,
? 3 CRH/CEB/mtc attachment:
GGNS response to the NRC Request for Additional Information, dated October 28, 1996 2.
Affirmation, per 10 CFR 50.54(f) of the GGNS Response to 92-08 RAI (Item 2C), dated November 6, 1995 cca Mr. R. B. McGehee (w/a)
Mr. R.
S. Reynolds (w/a)
Mr. J. E. Todrow (w/a)
Mr. H. L. Thomas (w/a)
Mr. J. W. Yelvertson (w/a)
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Mr. L. J. Callan (w/a)
Regional Administrator U.S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011 i
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l GNRO-96/00134
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i cc Mr. J. N. Donohew, Project Manager (w/2) office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Comunission 4
Mail stop 13M3 1
. Washington, D.C.
20555 i'
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e GNRO-96/00134 Grand Gulf Nuclear Station Response to Generic Letter 92-08 (Item 2c) RAI dated October 28, 1996 r
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4 GNRO-96/00134.
Attachment !
The following questions resulted from the Staff's preliminary review of the GGNS response to'the GL 92-Request for Additional Information, dated June 28, 1996.
1.
Ptr cables installed in exposed or enclosed gmps of cmduits. in air, the grouping factors given in Table IX of ICE *A Standard P-46-426 is specified for use when the spacing between the omduit surfaces is not greater than the conduit t
diameter or less than 1/4 of the omduit d4==ter. 'Ihe calculaticns did not use a ccoduit grouping factor. Provide a discussicn about conduit grouping factors at
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GCBGB N,- s
'Ihere are two parts to this response; one aglies to multiple conduits =c1naad in a cannon enclosure, and the other aglies to indivirtm11y enclosed ecoduits.
i Multiple conduits in a coman enclosure A derating factor of 48% was used for CENS configuraticms where two horizcntal omduits (1 x 2) are enclosed within a canum enclosure fabricated by installing
'Ihermo-lag 330-1 nominal 1-M" thick panels directly cn the surface of these ocnduits. 'Ihere are two instances of such ccnfiguraticos at CENSt conduits 1BBRNR42 and 1BBRNR43 are ec1rmd in such a ocnfiguratico for a a
length of approximately 18' conduits 1BBHNR43 and 1BBRNR45 are ecle=d in such a ocnfiguraticn for a e
length of appruximately 7' j
l Secticn 5.6.d of Engineering Report CKNS-96-0032 Revisicn 0 h=mts the developnent of the 48% derating based cn a conpariscn of test results for nultiple omduits versus a cable tray eninaad in a similar fire barrier configuraticn.
'Ihe test results derrmstrate that the anpacity derating for nultiple ecnduits (2 rows of 3 cmduits) ancinaad in a Ma thick baseline 'Iherno-Lag 330-1 with stress skin and truwel grade overlay (26%) are bounded by the airpacity derating for a 24" x 4" cable tray enclosed in a similar ocnfiguraticn (40%). A similar conpariscn of the GGNS configuraticn (1 row of 2 conduits) encinaad in nominal 1-M" thick 330-1 '1herno-Lag versus a cable tray enclosed in 1-M" thick 330-1 'Iherno-Lag, with a 770-1 overlay upgraded to a 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated fire barrier, leads to the conclusion j
that the tray ccnfiguraticn bounds the 2 conduit ocnfiguraticn. Based cn the significant ecnservatism of the asst.ined dar=Hng, it was ocmsidered r==amahle to ccnclude that the 9% derating required for cmduit gmping is inplicitly accounted for in the 48% derating, and therefore this 9% derating for ccmduit j
grouping was not explicitly applied to this ocnfiguration. Note also that, even if an additicnal 9% derating were to be applied to the specified installaticos, which have already been derated by 48%, the mininum anpacity margin for cables in thme ocnduits would be 14.5%.
Individually enclosed acnduits No g.touping factors were applied to individually enclooed cmduits. This was based cn the fact that in the two cases where enough separaticn did not exist to individually enclose conduits, a ccnnon enclosure was utilized.
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5 GNRO-96/00134 J-Omversely, if conduits were indivia=11y anele =ad, they were a:nsidered to have sufficient separaticn and adequate margins to justify not explicitly applying a omduit grouping factor.
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Due to *Ihermo-Lag tolerances, exact separaticn between conchait surfaces can not be ncn-destructively determined for indiviaully enclosed conduit cmfiguraticms.
Based on' further review of. individually enclosed conduits, it has been deramimd that there are same cases dere the spacing between two adjacent omduits may be -
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less than ene conduit diameter (but greater than W conduit diameter). 'Iberefore, a
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ocnduit grouping factor of 0.91 (three ocmduits in a horizcntal row) can be cmservatively applied to all cables routed in power and centrol ocnduits within 4
'ths scope of Engineering Reports M 0006 Revisicn 0 and M 0032 Revision
- 0. 'Ihere are no emaaa within M 'Ihernr-Lag protected conduit installations which j
would require a derating higher than 0.91 (three ocnduits in a horizcntal row).
Although applicaticn of the 0.91 factor (9% derating) to base anpacities of all cables routed in power and ecntrol conduits results in r=4v=d anpacity margins for these cables, the min 4== anpacity margin fcr: aables routed in individually e
ane 1naad ocnduits, after applicaticn of this derg.ing, is 18.4 %.
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2.
It' is not clear how the licensee calculated the full load anperes (FIA) for j
applicWe ocnduits. 'Ihe cmstant KVA loads will draw 11 percent nore current at 90 pa ut of the rated voltage available at its tam 4n=1s. Additionally, some -
loads nay operate at overload or at a service factor of 15 percent. Accordingly,
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the FIA could be as high as 125 percent of the FIA at naminal voltage. 'Ihe licensee needs to address this aspect of system operaticn in the anpacity derating l
__ analysis.
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M RespCnset i
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h full load anpere (FIA) ratings for all power circuits were retrieved from am4,m=nt nameplate _ data and/or determined from available design informaticn. As i
' indicated in Generic letter 92-08, anpacity derating for 'Iherno-Lag has been characterized primarily as a cable life issue, with potential reducticn in the design life of cables, as a result of ocntinuous operaticn at higher than design tenperatures, m agrees with this characterizaticn, and therefore ocnsidered circuit loading for steady state operation, in order to evaluate the cables for continuous operaticn.
h undervoltage conditicos cited in the questicn are transient in nature and would not be present en a ocntinuous basis. Power cablea installed at M were procured for service canditicns which include emA*nr tenperatures not exceeding 90' C in normal operation, with up to 100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br /> of Nrwmcy" operaticn at 130
- C, per year for a 40 year service life. Cables i
within the socpe of this evaluaticn are expected to withstand the transient 1
overload conditions, which are ocnsidered to be part of the expected service omditions for power cables utilized at M, and operate for the design life of the 1lant carrying their normal steady state FIA. Ocntinuously energized ecostant KVA loads powered by cables within the scope of this evaluation are sized to drive I-no nere than 100% of their rated inaaceswer.
'Iherefore overlrnding of cables j~
connected to constant KVA loads, due to continuous operaticn at 115% of rated j
Iwaceswer, dces not require additional anyacity derating cmsideraticn.
3.
'Ibe actual percent fill of conduits (1BBAcr22, 1BBAcr23, 1BBAcr25) ave =adad the i
allowable percent fill., Provide justification for cable anpacity if the conduit fill exceeds the value given in National Electric Code (NBC) tables.
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GNRO-96/00134 GCHS Responses these ecoduits form penetrations at the ocntrol building to the auxiliary N41diny interface. They are not actually 7herno-Iag clad, but are enbecBed in the cancrete walls of the ocntrol building and auxiliary buildings where they interface. They were initially included in the Therno-Lag anpacity derating dauhane because cables within 7herno-Lag clad trays transiticn fran the ccntrol building to the auxiliary building via these penetraticns. However, in actual practice, no additicmal derating due to applicaticn of Therno-Iag is recpired for these conduits.
The actual fill within these penetraticms does exceed the 40% fill allowable by the NEC. 7hese overfilled penetraticns were evaluated and justified during the I
original plant construction by the AE.
The justificaticn took into consideraticn the cable diversity as well as the loads serviced by the cables, the majority of which are ocntrol/instrumentatico circuits, or interinittent loads O(Ns).
4.
Base ampacities for #12 AWG control cables in random fill trays are from Table 11 or 12 of ICEA P-54-440 (1972). These tables are for 601-2000 volt cables. What is the voltage rating of the control cables (2/C, 4/C, 7/C, 12/C #12 AWG)?
GGHS Respcase:
With the excepticn of cable codes CBT (12/C #12 ANG), CYT (12/C #12 ANG), and CY4 i
(4/C #12 AWG), all ccntrol cables have a 1 kV voltage rating. Cables with codes CBT and CYT are rated at 600 V.
Cables with code CY4 were originally supplied with a 1 kV rating, but mh=;mtly supplied with a 600 V rating, so they will all be asstuned to be rated at 600 v. Cables with the above identified codes are jacketed cables with ncn-jacketed ocnductors. 7herefore, the appropriate cable anpacity (I ) for cables with these three codes should be retrieved from table 3 of o
ICEA P-54-440 (1972). All other #12 AW3 cables within the scope of this evaluaticn are jacketed cables with jacketed conductors, and therefore the appropriate cable anpacity (I ) for these cables should be retrieved from table 12 of ICEA P-54-440 (1972), as they have been. Cable anpacity (I ) for #12 AWG cables was not retrieved from Table 11 of ICEA P-54-440 (1972), since none of these cables are triplexed. All circuits utilizing cables with codes CBT, CYT, and CY4, routed in the two 7herno-Iag protected cable trays (7 cables total), were re-evaluated utilizing cable anpacities (Ix) based on Table 3 of ICEA P-54-440 (1972).
7his re-evaluaticn shows that the affected cables have anpacity margins in excess of 35%.
Tables 11 or 12, as appropriate, were utilized by the AE for power cables installed within open top trays at CENS during original plant design and ecostructicn. This practice was considered appropriate for power cables within the scope of this evaluaticn, since these are either triplexed cables with jacketed conductors, or jacketed cables with jacketed ocnductors. Ctnsequently, cable anpacities (I ) frun Tables 11 or 12 of ICEA P-54-440 (1972) were utilized o
for power cables within the scope of this evaluation.
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5.
What ampacity derating test or analysis bounds those configurations in Section 13.1.3.b.11 13.1.3.b.12 of licensee
- document, Engineering Standard ES-027. The licensee is requested to provide the ampacity derating parameters with applicable technical justification for the subject configurations.
02G Response Grand Gulf Nuclear Station (G2E) had no installed Therno-lag ccnfigurations as identified in Engineering Standard ES-02, Section 13.1.3.b.11 or 13.1.3.b.12 at the tine Engineering Reports Ib. G26-96-0006, Rev. O and 03 E-96-0032, Rev. O were issued. Although Engineering Standard ES-02 provides installation details for these two ecnfiguraticns, the standard also requires IOclear Plant Engineering appzwal prior to installing or nodifying 'Iherno-Lag enclosures. This design review and approval is specifically required to ensure the installaticn is bounded by tested configuraticos and potential affects cn design analyses (supports, anpacity & rating, etc.) have been evaluated. 'Iherefore, Engineering Report No.
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CONS-96-0006, Rev. O was correct and addressed all installed 'Iherno-Iag enclosure ccnfiguraticns at G2G at the time of issuance.
l Although not originally utilized or planned to be used, the ocnfiguraticn identified in ES-02, Section 13.1.3.b.12 was determined to be required as a result of field changes identified during actual upgrade of the 'Iherwo-Iag enclosures during RF08. As a result, anpacity derating for this ccnfiguraticn was evaluated and a derating factor of 23% was established.
'Ihis evaluatico utilized a similarity analysis like the cne used in Engineering Report No. GGG-96-0006, Rev.
O.
Specifically, the configuraticn identified in ES-02, Section 13.1.3.b.12 (1/2" base 'Iberno-lag 330-1 material with a 1/4" overlay) was conpared to etnfigurations evaluated in Engineering Report 1b. G25-96-0032, Rev. O, Section 5.6.c ' Single canduits clad in Thermo-lag 330-1/770-1, % ad63 to a 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> fire barrier rating". Engineering Report Ib. G2E-96-0032, Rev. O, Secticn 5.6.c established a 23% anpacity derating factor based cn conparison to anpacity derating test performed for 'IVA and TSI at Omega Point Iaboratories (Report IOmbers 11960-97337
& 97338).
A conparison of the 13.1.3.b.12 configuraticn and ocnfiguraticns utilized in the OPL test was performed for critical parameters as established in Secticn 6.1 of both Engineering Report IArnbers GGNS-96-0006 and G2G-96-0032 04aterial Type, 14aterial 'Ihickness, Stress Skin Incaticn, and Raceway / Base Material / Overlay Material Interface Mechanisms). 'Ihis ccrnpariscn determined that with regard to anpacity derating, the configuraticos identified in ES-02, Section 13.1.3.b.12 is bounded by those tested at OPL (Report Numbers 11960-97337 &
97338).
'Iherefore, the 23% ampacity derating factor established in Engineering Report Ib.
03E-96-0032, Secticn 5.6.c is bounding for the configuraticn identified in ES-02, Secticn 13.1.3.b.12.
A review of the configurations identified in ES-02, Secticns 13.1.3.b.11 and 13.1.3.b.12 determined that the 13.1.3.b.12 configuratica is a worse case with regard to anpacity derating. 'Iherefore, the anpacity derating factor established for the 13.1.3.b.12 configuratirm will bound the configuraticn identified in ES-02, Section 13.1.3.b.11.
As part of the paper work close out for the 'Iherno-Iag Upgrade ledification at 02E, Engineering Report Ib. GC26-96-0006 is being "as-built" to include an anpacity derating factor for the two configurations identified in ES-02, Secticns 13.1.3.b.11 and 13.1.3.b.12.
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1 6.
Sections 6.1.1 and 6.1.2 of the Engineering Report GGNS-96-0006 which was part of the licensee submittal dated June 28, 1996, contains a reference to both conduit and air drop fire barriers (i.
e.,
Flexi-Blanket 330-660) material properties. The licensee should explain how the installed configurations are bounded by the referenced ampacity
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derating tests. 'Ihe licensee is requested to describe gemetrically the fire barrier ocnstruction and identify the anpacity derating test being considered for the specific 'Iberno-Lag fire barrier configuraticos.
G WB Response G2s did not specifically establish an ampacity derating factor for Flexi-Blanket 330-660 material in Engineering Report GGNS-96-0006, Rev.
O.
Use of Flexi-Blanket 330-660 material at GGNS is limited to runs of less than three linear feet on conduits / air drtps.
'Ihis short distance (<3 linear feet) will mitigate local heating effects by conducting heat laterally alcng the length
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of the ocnduit and cirutit ccoductors.
"Iherefore, G2G cxnsiders the anpacity j
derating factor established for the specific conduit / cable tray arrangement as i
bounding for the short runs of conduit / cable air drop enclosed with Flexi-Blanket 330-660 material.
I Althcu3h (I2G considers the above approach ccnservative and acceptable, a nore detailed review of the Ot26 site specific use of Flexi-Blanket 330-660 material 1
was made. A review of the ' Safety Evaluaticn by the Office of Nuclear Reactor Regulaticn - Anpacity Issues Related to 'Iherno-Lag Fire Barriers - Texas Utilities Electric Chrpany - Comanche Peak Steam Electric Staticn, Unit 2 - Docket No. 50-446" was made with regard to anpacity derating issues for Flexi-Blanket 330-660 material. Page No. 8, Paragraph No. 4 of the above safety evaluation discusses 'IU Category 3 configuraticns (Flexi-Blanket). 'Ihis paragraph describes the worst-case ocnfiguration (candait-cable tray installaticn) and states: "It is expected that the anpacity derating margin of 30 percent for the specific cables in this cxnfiguration at CPSES, thit 2 would bound the Category 3 configurations'. A similar carparisan at G2G can be nade. In all cases except cne, Flexi-Blanket material at GGG is installed cn conduits and cable air drcps entering cable tray enclosures. 'Ihe cne exct.pticn involves a 4" cxnduit which is primarily wrapped with nominal 1 1/4" thick 'Iherno-Lag 330-1 prefabricated conduit secticos. A short section (approximately 2 linear feet)of this cxnduit has the 330-1 material removed and protecticn is provided by Flexi-Blanket 330-660 material. A review of all circuits at G2G, which are enclosed in the Flexi-Blanket 330-660 material, determined that a muumam ampacity derating reargin of 36.6% is available after base anpacities are considered
'Iherefore, even using the nore acuservative approach outlined in the safety evaluaticn for 'IU identified above, the 36.6%
anpacity derating margin available at G2E is certainly W%d by the 30% margin determined to be acceptable at 'IU.
t GNRO-96/00134 References Page 1 of 1 I
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References:
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Letter C. R. Hutchinson to the U.S. Nuclear Regulatory Commission, l
dated March 29, 1995 - Response to Follow-up to the Request for Additional Information (RAI) Regarding Generic Letter 92-08 Issued Pursuant to 10CFR50.54(f) on December 28, 1994: "Thermo-Lag 330-1 Fire Barriers".
I 2.
Letter C. R. Hutchinson to the U.S. Nuclear Regulatory Commission, dated December 21, 1994 - Response to Follow-up to the Request for Additional Information (RAI) Regarding Generic Letter 92-08 Issued Pursuant to 10CFR50.54 (f) on December 21, 1993: "Thermo-Lag 330-1 Fire Barriers".
3.
Letter U.S. Nuclear Regulatory Co mission to C. Randy Hutchinson, dated November 6, 1995 - Request for Additional Information Regarding Generic Letter 92-08, "Thermo-Lag 330-1 Fire Barriers".
4.
Letter C. R. Hutchinson to the U.
S. Nuclear Regulatory Commission, dated June 28, 1996 " Response to the Requ6st for Additional Information Regarding Generic Letter (GL) 92-08 Item 2(c), Thermo-Lag Fire Barriers, dated November 6, 1995 ".
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5.
Letter U. S. Nuclear Regulatory Commission to J. J. Hagan,' dated i
October 28, 1996 " Request for Additional Information Related to Ampacity Derating issues for Thermo-Lag Fire Barriers for Grand Gulf Nuclear Station".
6.
Engineering Report No. GGNS-96-0006 Revision 0, " Grand Gulf Nuclear Station Engineering Report for Evaluation of Ampacity Deratings for Thermo-Lag Fire Barrier Enclosed Cables in Fire Areas / Zones OC202, OC40;2, OC702 and 1A316".
7.
Engineering Report No. GGNS-96-0032 Revision 0, " Grand Gulf Nuclear Station Engineering Report for Evaluation of Ampacity Deratings for Thermo-Lag Fire Barrier Enclosed Cables in Fire Areas / Zones OC214, OC302, OC308 and 1A539".
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l l to GNRO-96/00134-Grand Gulf Nuclear Station Response to Generic Latter 32-08 (Item 2C) RAI dated November 6, 1995 Affirmation per 10CFR50.54 (f) 4 l
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1 BEFORE THE l
UNITED STATES NUCLEAR REGULATORY COMMISSION LICENSE NO. NPF-29 DOCKET NO. 50-416 i
IN THE MATTER OF MISSISSIPPI POWER ti LIGHT COMPANY and q
SYSTEM ENERGY RESOURCES, INC.
j and SOUTH MISSISSIPPI ELECTRIC POWER ASSOCIATION and ENTERGY OPERATIONS, INC.
AFFIRMATION l
I, J. J. Hagan being duly sworn, state that I am Vice President, Operations GGNS of Entergy Operations, Inc.s that on behalf of Entergy Operations, Inc., System Energy Resources, Inc., and South Mississippi Electric Power Association I am authorized by Entergy Operations, Inc. to sign and file with the Nuclear Regulatory Commission, this response (GNRO-96/00134)to the Generic Letter 92-08 Request for Additional Information dated October 28, 1996 for Grand Gulf Nuclear Station; that I signed this response as Vice President, Operations GGNS of Entergy Operations, Inc., and that the statements made and the matters set forth therein are true and correct to the best of my knowledge, information and belief.
W-,
'J.
.hagan STATE OF MISSISSIPPI COUNTY OF CLAIBORNE SUBSCRIBED AND SWORN TO before me, a Notary Public, in and for the County and State above named, this 23 day of Decemberz,1996.
Ab.
Ab M
Notary Public '
Notary Public State of Mississippi At Large My Commission Expires: February 1, 69F BONDED THRU HEIDEN-MARCHETil