ML20065T161

Forwards Response to NRC SER & Science Applications,Inc Technical Evaluation Rept Re Station Blackout.Responses Cover Alternate Ac Power Source,Compressed Air & Effects of Loss of Ventilation

ML20065T161
Person / Time
Site:	Beaver Valley
Issue date:	12/20/1990
From:	Sieber J DUQUESNE LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
TAC-68510, TAC-68511, NUDOCS 9012270292
Download: ML20065T161 (8)

Text

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December 20, 1990

. e nmu U. S.-Nuclear Regulatorv Commission Attn: Document Control Desk Washington,JDC ~20555

Reference:

Beaver-Valley Power Station, Unit No. 1 and No. 2 '

BV-1 Docket No. 50-334, License,No. DPR-66 BV-2 Docket No. 50-412, License No NPF-73 Response to Safety. Evaluation Report for Gtation Blackout

_(TAC Nos. 68510 and 68511)

Gentlemen:

By- letter dated April- 14, 1989, Duquesne Light Company (DLC) submitted; its response to the Station-Blackout (SBO) rule for Beaver

Valley Power Station,- Units 1 and 2, in accordance with 10 CFR 50.63.J Supplemental-information was provided by letters dated March

.30, 1990, June-29, 1990, and July 27, 1990.

The; NRC staf f,- by letter dated November :23, 1990, transmitted to DLC- the' Staff's Safety. Evaluation Report (SER) related to SBO and the

-Technical LEvaluation Report (TER) developed by Science Applications International Corporation (SAIC) for the-Boaver Valley Power Station, Units 1 L&'-2. Based .on the Staff's review, it was concluded that.

DLC's ' proposed method of; dealing with-a SBO,to be in conformance with

.tho -Rule -contingent- upon receipt-of confirmation from DLC that the hardware and' associated procedure - modifications,- including _those resulting from _the _ recommendations ; documented. in the SER, will'be

-implemented. The--letter required a response within 30 days of the date=of the SER in accordance with 10 ,CPR 50. 63 (c) (4) .

We'<have evaluated- the- recommendations contained in the SER and find them . acceptable' for implementation at BVPS. Attachment-1 to.

this  ; letter' describes how. we plan to implement each. of the recommendations. As noted in the--SER, the charging pump at Unit 2-Twill.:be addressed -as a' discretionary load for Unit 2 under blackout conditions Land Lprocedurally addressed in the Emergency. operating.

Procedures! (EOP's).for-SBO'to provide operator flexibility. 'The Unit

2- Emergency Diesel _ Generators have suff.icient capacity to power the-1 Unit 1 charging pump for the condition when Unit 1 is the blacked out unit.

9012270292 901220 ' 0 PDR ADOCK 05000334 '

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. Beaver Valley Power Station, Unit Nos. 1 &2 Docket No. 50-334, License No. DPR-66 Docket No. 50-412, License No. NPF-73 Page 2 In accordance with 10 CFR 50.63(c)(3), the modifications and procedure changes associated with the AAC cross-tic are required to be completed within two years after the notification by the Director, Office of Nuclear Reactor Regulation, which was provided on November 23, 1990. Since our Alternate AC (AAC) power source will involve cross-tying busses between Units 1 and 2, installation and testing will require successive refueling outages at both units to fully implement the cross-tic capability. Therefore, the schedule for completion may need to be extended, dependent on the scheduled refueling outage dates for Unit 1 and 2. Presently, the projected schedule for Unit 2's 3rd Refueling Outage is March 1992, and Unit l's 9th Refueling Outage is September, 1992. At the end of the 9th Refueling Outage for BVPS Unit 1, the cross-tie for both Units should be fully operational.

1. there are any questions on this matter, please contact my office.

Very truly yours, v __

. D. Sieber Vice President Nuclear Group cc: Dr. T. Murley, Direccor of Office of NRR Mr, J . Beall, Sr. Resident Inspector Mr. T. T. Martin, NRC Region I Administrator Mr. A. W. DeAgazi _ Project Manager Mr. R. Saunders (VtPCO)

NUMARC l

1

p. ATTACHMENT &

.BVPS Station Blackout Safety Evaluation Report Responses 2.2.2 Proposed AAC Power Source Recommendation:

DLC -~ 'should 'have appropriatre procedures to ensure that the Containment Air Recirculation (CAR) fans and the Containment -

Instrument Air Compressors (CIAC's) are turned off in the 4

-NBO -unit during LOOP conditions and a station blackout in.

the. adjacent unit. In' addition, DLC should conductJthe appropriate 7Ju: tests in accordance with the guidance of- -

NUMARC 87-00, Appendix B, Item B.12 to demonstrate that'it can be brought on line within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />.

Response

-Procedures will be developed for SBO which will include provisions for shutting down .the CAR .f ans - and the ,

CIAC's .at the non-blacked out unit. -The procedure? _

-development 'will : coincide. With -the SBO modification

')

work for the' Alternate AC (AAC) cross-tie.

'Our station blackout supplemental submittalEdocuments Beaver Valley's capability to withstand =a'- station >

' blackout without a charging pump at the-blacked-outL unit. As -noted in the SER, the charging pump is a discretionary load, and, as :such. station blackout.

procedures will 'be developed to- direct operators to power this- pump if sufficient-IAC power is1available during -an actual event. During an~ actual station blackout, operators. may find.that'someicomponentsLare not 'needed and are not being used . at the-non-blacked-out- unit. -Additional AAC power- that

.becomes available in this manner may allow the charging-

pump at the blacked-out unit tx) be energized 1during an t

actual- event. This procedural. flexibility is important to ensure operators respond to an actual event in a-

= manner that minimizes its effects on the station as a-whole.

Appropriate AAC tests will=be conducted in accordance-

with the guidance .ofl NUMARC 87-00, Appendix'B,Litem-  ;

B .12 , - to' demonstrate AAC capability within l'hourJ.. As noted- in- the cover letter to this enclosure,

. installation and testing of the electrical cross-tie between . units-will require nuccessive refbeling. outages at both units. . Therefore, the projected schedule.for-completion- of the modifications and associated testing will be the 9th refueling outage of BVPS Unit 1, in the fall of'1992.

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f ATTACHMENT 1 Pag.e 2 2.3.3 Compressed Air Recommendation:

DLC should develop procedures and simulate the appropriate actions and provide operator training to assure that decay heat removal can be adequately maintained.

Besponse:

Procedures will be developed and operational scenario's will be simulated as part of the operator training program for SB0 to demonstrate successful heat removal operation and coordination as recommended in the SER.

Procedure cavelopment and operator training will coincide with the SBO modification work for the Alternate AC cross-tie.

2.3.4 Effects of Loss of Ventilation Recommendation:

DLC should include in their station blackout procedures a provision to open the control room cabinet doors within 30 minutes after the onset of a station blackout event consistent with the guidance provided in NUMARC 87-00 Supplemental Questions / Answers.

Ensoonse:

The- SB0 procedures will include provisions for opening the appropriate cabinet doors in the control room that contain equipment required for station blackout within 30 minutes after the onset of a SB0 event consistent with the guidance of NUMARC 87-00. The procedure development will coincide with the SB0 modification work for the Alternate AC cross-tie.

2.3.5 Containment Isolation Recommendation:

DLC should review the operational features of the above listed valves (noted in the SER) and ensure that the station blackout procedures provide the means for proper control of these valves to assure containment integrity for the required station blackout duration.

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ATTACHMENT 1 Page 3 Resapjlgg:

The. SBO procedure vill include provisions for proper control of these valves to ensure containment integrity, as required, It is not anticipated that the subject valves noted in the SER will need to be actuated because of a station blackout, however the valves have the capability for manual closure with position indication, independent of the blacked-out unit's power suppliec, in the event containment integrity is required under SBo conditions. The procedure development will coincide with the SB0 modification work for the Alternate AC cross-tie.

2,3,6 Reactor Coolant Inventory Recommendation:

DLC should consider the additional losses '(170 gpm) and verify that the results _of generic analysis referenced in NUMARC 87-00 are applicable to the BVPS. DLC should also ensure that all of the assumptions in the referenced analysis bound the conditions of the BVPS reactors during the station blackout event, and include these in the documentation supporting the station blackout submittals.

Response

Based on our _annlyses, a reactor coolant loss of approximately 170 gpm does not result in core uncovery during' a 4-hour station blackout. This conclusion is consistent with SAIC's Technical Evaluation. It should be noted that our- Technical Specification limit for

" maximum _ allowable. Identified RCS leakage" is 10 gpm vs. the 25 gpm assumed by SAIC. Therefore, the assumed 170 gpm leakage rate and'the conclusions noted in the SER are conservatire.

The assumptions and results of our analyses will be maintained as part of c.ur S60 documentation.

2.5' Proposed Modification Recommendation:

DLC should p*ceide a full description including the nature and objectives of the required modifications identified above in the documentation supporting the station blackout submittals that is to be maintained by DLC.

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i b ATTNCHMENTil Page 4-Response:-

A- full description including the nature 1and objectives of. the required Alternate AC cross-tie modification for

-S BO will- be -included ,in the documentation supporting

-SBO and maintained on site by the licensee.

LFigure. l' is a diagram.' depicting the electrical cross-tie for Beaver Valley Power Station Units 1 & 2.

The. diagram identifies the new breakers.to be added to .

j existing switchgear and the new cubicle and breaker necessary for 4KVS-2D. Preliminary design work listing protection and relaying options hr.s been developed by-_ l the Controls Engineering Department of DLC. -4 Concurrently, investigations are proceeding to establish options.-for installation of hardware-items and -appropriate raceway and cabling systems to tie.

together the-. control features minimizing the operator actions necessary. -The design objectives- will recognize- the one hour maximum time period to.  !-

-accomplish the cross-tie.

The cross-tie- is to be implemented by tying the normal'

'4KV busses within each unit. The normal bus of one

-unit. Will- then be cross-tied to the normal bus of the second- unit. Control switches will.be installed in the --,

emergency switchgear rooms and in the normal switchgear rooms. The control switches will align-theLprotection and control- circuits to allow' -any of four -diesel generators: to power either. bus within the blacked out The . addition of these ' control switches will

~

unit.

allow greater operator ease-in aligningEthe unit rather j than performing individual breaker operations.  ;

1To fully. accomplish the alignment: will' require' an operator- to . assure the . loads have been shed from the normal busses." This. will be accomplished procedurally._ Procedure development will coincide with-the SBO: modification work for the Alternate AC a tcross-tie. i The. projected; schedule for completion- of -the

. . modifications, procedures and- associated' testing will be -the 9th refueling outage of-BVPS. Unit 1, in the fall

-oft 1992.

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ATTACHMENT 1 Page 5 2.6 Quality Assurance (QA) and Technical Specifications (TS)

Recommenda. tion:

DLC should verify that the station blackout equipment 13 covered by an appropriate QA program consistent with the guidance of RG 1.155. Further, this verification should be documented as part of the package supporting the station blackout rule response.

Response

A QA program that meets the guidance of Regulatory Guide 1.155, Appendix A is being developed to cover the SBO equipment being installed under the SBO modification work for the Alternate AC cross-tie. The verification of an appropriate QA program for SB0 equipment will be included in our supporting documentation for SBO and maintained on file by the licensee. We expect this program to be implemented by the end of 1991.

2.7 EDG Reliability Program Recommendation:

DLC should implement an EDG reliability program which meets the guidance of RG 1.155, Section 1.2. The EDG reliability program currently being revised by DLC should be evaluated and adjusted in accordance with RG 1.155. Confirmation that such- a program is in place or will be implemented should be included with the documentation supporting the station i blackout submittals.  ;

Resnonse: i l

We have committed to a target reliability of 0.975 and 1 that reliability is tracked and maintained under our existing program. We are enhancing that program based upon tho guidance given in NUMARC 87-00, Appendix D and working copies of Regulatory Guide 1.9 Revision 3, as appropriate. This program will meet the guidance of RG 1.155, Section 1.2. The EDG reliability program will be fully implemented by December 31, 1991.

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