ML20198D593

Submits Response to NRC 980619 RAI Re GL 92-08 Re Thermo-Lag Fire Barriers.Response Has Been Developed Based on Std Industry Practices &/Or Methodologies Previously Found Acceptable by NRC

ML20198D593
Person / Time
Site:	Grand Gulf
Issue date:	12/15/1998
From:	Hughey W ENTERGY OPERATIONS, INC.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GL-92-08, GL-92-8, GNRO-98-00101, GNRO-98-101, NUDOCS 9812230135
Download: ML20198D593 (12)

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.. lia 1 O Entargy Operations,Inc.

PO. Box 756 Port Gibson, MS 39150 I

Tel 601437-6470 W.K.Hughey Dwector Nuclear Safety & Fkwydatvry Affars December 15, 1998 i

l U.S. Nuclear Regulatory Commission l Document Control Desk Mail stop P1-37 Nashington, D.C. 20555

' subjects- Grand Gulf Nuclear station I Docket No. 50-416 License No. NPF-29 Response to the Request for Additional Information Regarding Generic Letter (GL) 92-08: Thermo-Lag Fire Barriers, dated June 19, 1998 GNRO-98/00101 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 l 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 barriers and the evaluation and application of ter.t results performed to

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determine the ampacity dorating of Thermo-Lag barriers.

By our letter dated June 5, 1997 (Reference 1), GGMs provided a response to the staff's Request for Additional Information (RAI) dated February 26, 1997 (Reference 2). The staff reviewed our June 5, 1997 submittal and ]

identified items needing clarification. The staff's RAI dated June 19, j 1998 (Reference 3) solicited responses from GGNs for the items requiring j clarification. The items contained in the staff's June 19, 1998 letter I were discussed between GONS and the NRC during teleconferences conducted l on June 17, 1998 and September 24, 1998, respectively. The intent of these  ;

discussions was to assess the staff's understanding of our conceptual plan j of action for addressing the staff's concerns delineated in the June 19, '

1998 RAI and to facilitate satisfactory resolution of Thermo-Lag ampacity dorating issues pursuant to Generic Letter 92-08 for GGNs. ,

I Attachment 1 provides our responses to the June 19, 1998 RAI. These l responses have been developed based on standard industry practices and/or methodologies previcusly found acceptable by the NRC.

During the september 24 teleconference, the staff specifically requested that our response discuss certain elemen% discussed during the teleconference. +

i% gyI 9912230135 981215 PDR ADOCK05000416]b P PDR iff, j L 1

l l December 15, 1998

GNRO-98/00101

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i j These elements include identification of any circuits with negative j i ampacity dorating design margin and corrective actions planned for 4

monitoring those circuits to ensure their continued acceptability, if I i warranted.

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Attachment 1 includes identification of those circuits with negative design margin for dorated cable ampacity. A detailed service life l j evaluation has been performed for the circuits encompar. sed by this '

j criteria and concluded that these cables are acceptable, with no l 4 corrective actions currently necessary. To ensure that pre-established j Full Load Amp (FLA) currents for these circuits are not exceeded, we plan l 4 to collect voltage and current data following maintenance activities that I may potentially result in FLA currents for these circuits being exceeded.

Should dorated ampacity limits be exceeded, an engineering review will be performed to access appropriate corrective actions.

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f During the June 17 teleconference, GONS was also requested to discuss a i question (Question 5) that was contained within s May 20, 1998 advance 1

copy of the June 19 Request for Additional Information. This question i requested clarification of the grouping factor applied to multiple i conduits contained within a single Thermo-Lag clad raceway at GONS.

j clarification by GON8's staff that the grouping factor applied w.as based I j on a worst case assumption prior to field walkdowns to confirm actual I i

raceway configurations. Subsequent to the field walkdowns, we identified l 4 that the assumed grouping factor was overly conservative for GONS l 4

configurations. Nevertheless, we elected to retain this additional I conservatism for the grouping factor applied to conduits enclosed within i GONS Thermo-lag clad raceway. Following this clarification, the staff withdrew guestion 5 from the June 19, 1998 Request for Additional Information.

This information is being submitted under affirmation in accordance with 10 CFR 50.54(f)(Attachment 2).

Please contact Charles E. Brooks at (601) 437-6555 should you have any questions, or require additional information.

Yours truly, WKE/CEB/ceb cc: see Next Page

I December 15, 1998 GKRO-98/00101 Page 3 of4 I

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l l WKN/CES/ cab attachment: 1. GONS response to the NRC Request for Additional

! Information, dated June 19, 1998

2. Affirmation, per 10 CPR 50.54(f) of the GGNS Response l to 92-08 Request for Additional Information, dated June 19, 1998 cca Ms. J. L. Dixon-Herrity, GGNS Senior Resident Inspector Mr. R. B. McGehee (w/a)

Mr. R. S. Reynolds (w/a)

Mr. H. L. Thomas (w/a) i Mr. Ellis W. Merschoff (w/a)

Regional Administrator U.S. Nuclear Regulatory Commission l Region IV 611 Ryan Plaza Drive, suite 400 Arlington, TX 76011 l Mr. J. N. Donohew, Project Manager (w/2)

(

office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission l Mail Stop 13H3 ,

j Washington, D.C. 20555

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becember 15, 1998 GWRO-98/00101 Page 4 0f 4 a

bcca' File (LCTS/RPTS) (w/a).

File (Eard Copy) (w/a)

File (MS&RA) (w/a)  ;

File (Central) (w/a) (14 )

3 cctuall' Mr. G. R. Ashley (AMO-LIC)  !

Mr. T. E. Barnett Mr. W. J. Beck (RB-LIC)

Mr. E. D. Berryhill Mr. S. J. Bethay(ECH-LIC) l Mr. D. G. Best

!- Mr. C. A. Bottomiller l' Mr. C. E. Brooks

. Mr. R. W. Byrd i Mr.='/. R. Cameron ,

. Mr. M. R. Cumbest

Mr. D. W. Chipley 1

. Mr. L. F. Dale j' Mr. L. F. Daughtery 1 Mr. C. M. Dugger (VP-W3) j Mr. W. A. Eaton i Mr. Ra K. Edington (VP-RB) j Mr. C. W. Elisaasser 4

Mr. E. C. Ewing (W3-LIC)

^,, Mr. W. K. Hughey j Mr. M. L. Bumphries  :

), Mr. C. R. Ettchinson (VP-ANO)

Mr. C. W. Lambert' ,

j Mr. G. B. Lantz  !

Mr. J. R. McGaha (ECH) j Mr. D. C. Miss (ANO) l Mr. R. V. Moomaw Mr. J. C. Roberts j Mr. 8. A. Rogers Mr. M. V. Rohrer i Mr. C. D. Stafford i Mr. L. G. Temple Mr. J. E. Venable Mr. D. W. Vinci (W3) i Mr. R. I. Wright I

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Attachment 1 to GNRO-98/00101 Grand Gulf Nuclea? Station

! Response to Generic Letter 92-08 Request for Additionkl Information dated June 19, 1998 l'

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GNRO-98/00101 Attachment 1 The following items require clarification as delineated in the staff's RAI dated June 19, 1998. These items were identified as a result of the staff's review of the GGNS response to the GL 92-08 Request for Additional Information, dated June 5, 1997.

GGNS Discussion:

To conservatively simplify the ampacity derating methodology, GGNS will use the ICEA Standard 40 degree C temperature for ampacity derating in the OC302 room rather than using 30 degrees C. Also, for the one GGNS tray that is clad with Thermo-Lag 330-1 nominal 1-1/4" thick panels the original 48% derating will oe used rather than 44%. Therefore, the ampacity derating correlation established in the paper entitled, " Fire Endurance and Ampacity Testing of One- and Three-Hour Rated Thermo-Lag Electrical Raceway Fire Barrier System" authored by Mark H.

Salley and Kent W. Brown will not be used. For the continuous duty constant KVA equipment (Z51-Control Room HVAC and Z77 -

Emergency Switchgear and Battery Rooms Ventilation fan motors) that has power cables contained within Thermo-Lag enclosed raceways, field measured voltage and Full Load Amp (FLA) current values have been taken. The PLA values have been corrected to the minimum anticipated grid voltage (0.992 per unit) to ensure that the highest anticipated normal operating current is used to evaluate the ampacity margin. Measures have been established to ensure that the corrected FLA currents for these circuits are not exceeded. As a result of applying these very cor.servative measures, all but three of the constant KVA continuous duty motor cables have been found to have acceptable design margins for derated cable ampacity. A detailed cable service life evaluation was performed for the three cables of concern. The useful service life for cables 1AB561041 (Q2Z77B001A Low Speed),

1AB561181 (Q2Z77C001AA Low Speed), and 1AB561201 (Q1Z77C001AA Low Speed) has been evaluated using Arrhenius methodology and found to be acceptable. The service life evaluation

conservatively uses 40 degrees C for the entire 3 month summer period and 30 degrees C for the remaining 9 months of the year.

Data obtained from the Plant Data System indicates that while the peak daily OC302 room temperature does occasionally exceed 30 degrees C during the summer months, it rarely ever approaches 40 degrees C. Therefore, the service life evaluation is very conservative for the conditions normally experienced by the subject cables, and would even encompass possible increased temperatures resulting during an unexpected fan outage.

Request for Additional Information - Questico 1:

In response to Question 2 of the staff's RAI, it is stated that

" Room OC302 has an average temperature of approximately 80 degrees F and typically a temperature of less than 86 degrees F (30 degrees C)." The ICEA Standard allows an ampacity factor of 1.09 for an ambient temperature of 30 degrees C provided the room temperature never exceeds that temperature.

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-l emc~98/00101 Attachment 1

.Therefore, a room temperature of 40 degrees C for some length of time and 20 degrees C for the remaining period, with the average-being 30. degrees C, will not qualify for an ambient room temperature of 30 degrees C. Confirm that the ambient temperature of Room OC302 will not ex6eed 30 degrees C. In addition, discuss the procedure that applies to monitoring and controlling the room temperature.

GGNS Response to Question 1:

i GGNS will use the standard 40 degree C ambient temperature in OC302 for determining derated cable ampacity.

Peak daily room temperature data was obtained from the Plant )

Data System for a perica of several years for purpose of  ;

developing a worst case temperature profile. This temperature profile has been used only in performing the service life evaluation for cables 1AB561041, 1AB561181, and 1AB561201. The I service life evaluation conservatively uses 40 degrees C for the l entire 3 month summer period and 30 degrees C for the remaining 9 months of the year. Data obtained from the Plant' Data System indicates that while the peak daily OC302 room temperature does occasionally exceed 30 degrees C during the summer months, it I rarely ever approaches 40 degrees C. Therefore, the service life evaluation'is very conservative for the conditions normally experienced by tne subject cables, and would even encompass possible increased temperatures resulting during an unexpected fan outage.

Dequest for Additional Information - Question 2:

Provide (1) the details of the analytical method used to calculate an ampacity correction factor of 44% and (2) a copy of the paper entitled, " Fire Endurance and Ampacity Testing of One-and Three-Hour Rated Thermo-Lag Electrical Raceway Fire Barrier System." Discuss if the paper is endorsed by the IEEE?

GGNS Response to Question 2:

l The 44% derating is no longer being used. GGNS will use the 48%

derating published in Omega Point Laboratories Report No. 11960-97333, "Ampacity Derating of Cables Enclosed in a Cable Tray with Thermo-Lag 330-1/770-1 upgrade Electrical Raceway Fire i Barrier System (ERFBS)" prepared for TVA and TSI. The 44%

l ampacity derating correlation established in the paper entitled, j- " Fire Endurance and Ampacity Testing of One- and Three-Hour Rated Thermo-Lag Electrical Raceway Fire Barrier System" i authored by Mark H. Salley and Kent W. Brown will not be used.

Therefore, the ..'ipacity derating concern for 44% is negated.

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, GRERO-98/00101

Attachsnemt 1

! Request for Additional Information - Question 3:

l It is the staff's understanding that the licensee stated to the effect that all loads except the emergency switchgear and battery rooms cooling motor will have at least 100% of the rated voltage for all conditions. The emergency switchgear and battery rooms cooling motor will have instead at least 98% of rated voltage for all conditions. Hence, no adjustment of full-load current for constant KVA loads due to voltage contingencies is required. Confirm that these statements are correct for Grand Gulf and discuss the effects of variation in voltage experienced by the constant KVA loads in the past at Grand Gulf.

GGNS Response to Question 3:

GGNS has used the minimum anticipated grid voltage (0.992 per i unit) in determining the minimum available terminal voltage for the continuous duty constant KVA equipment (Z51-Control Room HVAC and Z77 - Emergency Switchgear and Battery Rooms

Ventilation fan motors) that has power cables contained within Thermo-Lag enclosed raceways. As expected, all of these fan motors would experience less than 100% of rated voltage for the j 0.992 pu condition. However, as discussed below this is a

, concern for only three cables and these have been evaluated and found to be acceptable.

l For this same continuous duty constant KVA equipment, field measured voltage and FLA current values have been taken. The FLA current values have been corrected to the minimum anticipated grid voltage (0.992 pu) to ensure that the highest anticipated normal operating current is used to evaluate the l cable ampacity margin. As a result of applying these very conservative measures, all but three of the constant KVA continuous duty motor cables have been found to have acceptable design margins for derated cable ampacity. A detailed cable service life evaluation was performed for the three cables of l concern. The useful service life for cables 1AB561041 l

(Q2Z77B001A Low Speed), 1AB561181 (Q2Z77C001AA Low Speed), and 1AB561201 (Q1Z77C001AA Low speed) has been evaluated using Arrhenius methodology and found to be greater than 40 years under the evaluated conditions. 1 i

1 Measures have been established to ensure that the corrected FLA l currents for these circuits are not exceeded. Tnese measures 1 require that voltage and current measurements are taken when any activity is performed which could cause the corrected FLA current of the equipment to be exceeded. If the corrected FLA current of the equipment exceeds the derated ampacity limits I

established, Engineering must be notified so that a detailed review can be performed and the appro;riate corrective action initiated, if necessary.

' The evaluations performed indicate that no corrective actions are currently necessary. The measures that are being established will ensure that if conditions change in such a manner as to affect these evaluations, Engineering will be i notified so that appropriate corrective actions can be initiated 1 as necessary.

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f GLUto-99/00101 Attachusent 1

. Request fee Additional Information - Question 4:

In response to Question 1 of the staff's RAI, the licensee stated that an ampacity derating factor of 48% is_used for the configuration of two horizontal conduits enclosed by Thermo-Lag; however, an ampacity derating factor of 44% was calculated for the conduits using the analytical method described in the response to Question 2 of the staff's. RAI. Discuss which derating factor is correct and identify which raceways enclosed by Thermo-Lag would have sufficient design margin given an ampacity derating factor of 48%. I I

GGNS Lesponse to Question 4:

The previously used 44% derating did not apply to conduit configurations. However, GGNS currently uses only the 48%

derating, therefore this clarification is no longer necessary. l l

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mmo-98/00101 Attachment 1

References:

1. -Letter J. J. .Hagan to the U. S. Nuclear Regulatory Commission, dated' June 5, 1997 Response to the " Request'for Additional Information Regarding Generic Letter 92-08 (GL) Item 2(c): '

Thermo-Lag Fi. Barriers" dated February 26, 1997.

2. Letter U. S. . Nuclear Regulatory Commission to J. J. Hagan, dated February 26, 1997 " Request for Additional Information Related to Thermo-Lag Fire Barriers, Generic Letter 92-08, Grand Gulf Nuclear Station,. Unit 1 (TAC No. M85554)".

3. Letter U. S. Nuclear Regulatory Commission to J. J. Hagan, dated June 19, 1998 " Request for Additional Information Related to Thermo-Lag Fire Barriers and Generic Letter 92-08 for Grand Gulf Nuclear Station, Unit 1 (TAC No. M82809)".

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, CNRO-98/00101:

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1 Attachment 2 to l

i GNRO-98/00101 l Grand Gulf Nuclear. Station ,

Response to Generic Letter 92-08' l'

Request for Additional Information dated June 19, 1998 Affirmation per 10CFR50.54(f) l l

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. , CNRO-98/00lOl BEFORE THE UNITED STATES NUCLEAR REGULATORY COMMISSION LICENSE NO. NPF-29 DOCKET NO. 50-416 IN THE MATTER OF ENTERGY MISSISSIPPI and SYSTEM ENERGY RESOURCES, INC.

and SOUTH MISSISSIPPI ELECTRIC POWER ASSOCIATION and ENTERGY OPERATIONS, INO.

AFFTRMATTON I, William K. Hughey, state that I am Director, Nuclear Safety & Regulatory Affairs of Grand Gulf Nuclear Station; that on behalf of Entergy Operations, Inc., System Energy Resources, Inc., and South Mississippi glectric Power Association, I am authorized by Entergy Operations, Inc. to sign and file with the Nuclear Regulatory Commission, this response (GNRO-98/00101) to the Generic Letter 92-08 Request for Additional'Information dated June 19, 1998 for Grand Gulf Nuclear Station; that I signed this response as Director, Nuclear Safety & Regulatory Affairs of Grand Gulf Nuclear Station, and that the statements made and the matters set forth therein are true and correct to

- .the best of my knowledge, information and belief, h

William i(. Hughey STATE OF MISSISSIPPI COUNTY OF CLAIBORNE SUBSCRIBED AND SWORN TO before me, a Notary Public, in and for the County and

j. -Sthte above named, this /F # day of necamhar, 1998.

(SEAL).

_ q Notary #Public

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