ML20044C885

Advises That Response to NRC Request for Addl Info Re Containment Electrical Penetration Protection Will Be Provided to NRC by 930820,per Electrical Distribution Sys Functional Insp

ML20044C885
Person / Time
Site:	Arkansas Nuclear
Issue date:	04/30/1993
From:	James Fisicaro ENTERGY OPERATIONS, INC.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
2CAN049305, 2CAN49305, NUDOCS 9305130206
Download: ML20044C885 (2)

Text

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, , ?o April 30,1993 2CAN049305 U. S. Nuclear Regulatory Commission Document Control Desk Mail Station P1-137 Washington, DC 20555

Subject:

Arkansas Nuclear One - Unit 2 Docket No. 50-368 License No. NPF-6 Response To NRC Request for Additional Information on the ANO-2 Containment Electrical Penetration Protection Gentlemen:

As part of the Arkansas N 2 clear One, Unit Two (ANO-2) electrical distribution system functional inspection (EDSFI), the NRC inspectors raised a question with regards to whether ANO-2 maintained adequate containment electrical penetration protection for the potential long duration, low energy ove.rload condition. In the ANO-2 NRC inspection report dated November 21,1991 (50-368/91-02), the inspection team reviewed the updated safety analysis report and related documentation given the absence of full overload protection, and agreed that ANO had implemented the approved design basis.

In NRC letter dated June 18,1992 (2CNA069201), the NRC Staff requested that ANO-2 reassess the existing coordination of the primary and secondary cont;.inment penetration devices to assure that adequate protection was provided for the full range of overcurrent conditions. Entergy Operations provided the ANO-2 response in letter dated September 4, 1992 (2CAN099202). This letter documented the ANO-2 licensing basis and, where possible, proposed potential enhancements to the 480vac penetrations to better protect for potential overloads. Subsequent to this letter, additional information was provided informally for the 120vac/125vde penetration circuits where full overload protection is not prosided.

Based on review of the ANO-2 submittal, the NRC requested additional information in letter dated February 26,1993 which the Staff considered necessary to resolve the ANO-2 penetration protection issue. The information requested included revising the reactor building penetration protection calculation, determining those areas where both primary and backup protection is not prosided, providing additional design details for thermal overload heater protection including conductor ampacity, and providing discussion of design limitations and technicaljustification where overload protection cannot be provided.

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2CAN049305 Page 2  !

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In review of the Staffs request, Entergy Operations determined that this level of detail l could not be readily provided without the expenditure of significant manpower resources l and analysis. Conference calls were conducted with the Staff on April 9, and April 22,1993  !

where Entergy Operations explained that this information was beyond the ANO-2 licensing i basis and could not be readily provided. As a result, the Staffindicated that by this request [

that they had not reached a conclusion as to whether ANO-2 was or was not within its  !

licensing basis, but that the information was needed to make a further determination of the potential ANO-2 safety significance given the existing level of penetration protection. The  ;

Staff also stated that it was not their intent to require ANO to generate new information ,

concerning penetration conductor damage based on interpretations of existing tests or the  !

conducting of new tests. Therefore, it was agreed that the following ANO-2 information l would be provided to the Staffin lieu of the specific information requested by the February ,

26,1993 request for additionalinformation:  :}

1. A conductor based evaluation will be performed using a conservative conductor size to f develop conductor capability curves in the overload range,

2. the reactor building penetration protection calculation (Calc. 85-E-Oll8-01) will be f' modified to remove the penetration protection figures which are not being utilized for any ANO-2 applications,  ;

3. a figure will be added to the penetration protection calculation to show that the fuse curve utilized to evaluate the penetration circuit protection envelopes the worst case  :

fuse application, and to j

4. expand the penetration table previously provided in our September 4,1992 submittal to include the remaining penetrations where protection is not provided for the full j conductor capability curve.  ;

i  ;

This information will be provided to the NRC by August 20,1993. Due to a conflict in l ANO engineering resources to prepare this information, it was agreed with the Staff that the  ;

action to perform an evaluation of the ANO-1 penetration protection capability would be  ;

, deferred from December 31,1993 until April 29,1994 as previously committed in Entergy  ;

Operations letter dated August 3,1992 (OCAN089201). l f

If you have any questions on this matter, please contact me. i Very truly yours, l

w 55 James J. Fisicaro Director, Licensing l

JJF/sab l

U. S. NRC l Y

• April 30,1993 i

,* 2CAN049305 Page 3 l cc: Mr. James L. Milhoan 1 Regional A.dministrator U. S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-8064 NRC Senior R.esident Inspector Arkansas Nuclear One - ANO-1 & 2 Number 1, Nuclear Plant Road RusselMlle, AR 72801 Mr. Roby B. Bevan, Jr. ,

NRR Project Manager Region IV/ANO-1 U. S. Nuclear Regulatory Commission NIUt Mail Stop 13-H-3 One White Flint North 11555 Rockville Pike Rockville, MD 20852 Mr. Thomas W. Alexion NRR Project Manager, Region IV/ANO-2 U. S. Nuclear Regulatory Commission i NRR Mail Stop 13-H-3 One White FEnt North 11555 Rockville Pit:e Rockville, MD 20852 .

Ms. Greta Dicus l Arkansas Department of Health -

Division ofRadiation Control and Emergency Management 4815 West Markham Street Little Rock, AR 72205 1