ML20205G379

Forwards Responses to NRC Requests for Info Re Environ Qualification Program,Including High Energy Line Break W/ Superheat & Qualification Methodology for Submergence

ML20205G379
Person / Time
Site:	Beaver Valley
Issue date:	03/24/1987
From:	Carey J DUQUESNE LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
RTR-REGGD-01.089, RTR-REGGD-1.089 2NRC-7-056, 2NRC-7-56, TAC-62897, NUDOCS 8703310443
Download: ML20205G379 (5)

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M 2NRC-7-056 Bemr Vall o. 2 Unit Project Organization Telecopy ( 2 Ext.160 P.O. Box 328 March 24, 1987 Shippingport, PA 15077 United States Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555

SUBJECT:

Beaver Valley Power Station - Unit No. 2 Docket No. 50-412 NRC/NRR Environmental Qualification Review DLC Response to Additional Questions Gentlemen:

This letter is provided in response to recent NRC/NRR requests concerning the BVPS-2 Environmental Qualification Program specifically on: 1)

High energy line break with superheat and 2) Qualification methodology for submergence. Information regarding these items is provided in Attachments I and II respectively. The purpose of providing this information is for NRR review and reference in the BVPS-2 final EQ SER presently in preparation.

If there are any questions regarding these items, please contact Mr. E. T. Eilmann at 412/393-7895.

DUQUESNE LIGHT COMPANY J. . Carey Vice President, Nuclear Group KEW/blb MCE/KEW/50412 AR NAR A cc: Mr. P. Tam, NRC Project Manager Y

i M r . J. Beall, NRC Sr. Resident Inspector j Dr. T. E. Murley, NRC Region I Administrator k INP0 Records Center 8703310443 870324 PDR ADOCK 05000412 A PDR ,

United States Nuclear Regulatory Comission Mr. Harold R. Denton NRC/NRR Environmental Qualification Review Page 2 COMMONWEALTH OF PENNSYLVANIA )

) SS:

COUNTY OF BEAVER )

On thisrkM day of //2A //) , / M [ , before me, a Notary Public 'in and for said Commonwealth and County, personally appeared J. J. Carey, who being duly sworn, deposed and said that (1) he is Senior Vice President of Duquesne Light, (2) he is duly authorized to execute and file the foregoing Submittal on behalf of said Company, and (3) the statements set forth in the Submittal are true and correct to the best of his knowledge.

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L /NNotary6CbfM Public SHEIG E. FAT!00s, s0ftJrf PutrdC DelPPIRAPMT 0080. SEAVER CDUln?

WT COBRISSION DPIRES SCT. 23.1989 Wembcr. Pearsyfonie Asseeleties of sleenrius

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+, Attachment I p~

Position on Regulatory Guide 1.89 As it Relates to Appendix E of the  ;

Environmental Equipment Qualification Report i t

tion Regulatory Position C.4 of Regulatory Guide 1.89 " Environmental Qualifica-of Certain Electric Equipment important to Safety for Nuclear Power Plants" states that four specific issues be addressed for the qualification of each category lE component.

Appendix E " Evaluation of the Effects of Super-heated Stesn Blowdown on Equipment Located Outside Containment" of the BVPS-2 Environmental Equipment Qualification (EEQ) Report addresses these issues for the superheated steam blowdown event.

superheated blowdown event as follows: BVPS-2 addresses these criteria for the

1) Consideration of spectrum of breaks:

For the purpose of specifying environmental parameters, break size is chosen based on a review of WOG data to result in the maximum MSVH compar 0.5 f tpent temperature at the time of the tube uncovery. This is a break at 70% power. For the the superheat release for the 0.9 f t rpose of thermal lag analysis, stesnline isolation and blowdown terminationbreak istimes superimposed on thg of the 0.4 break, thegeby enveloping the spectrum of breaks from 0.4 to 0.9 f t .fg Tne 0.4 f t' break is evalugted to 1800 segonds, thereby enveloping all breaks smaller than 0.4 f t'.

seconds, the blowdown terminationThetime.

1.0 ft break is evaluated to t=600 Based on the above the spec-trum event.

heat of break sizes is adequately addressed for the MSLB with super-2)

The potential recovery need for operations: the equipment later in the event or during Equipment is shown as qualified by Appendix E for the MSLB with super-heat event based on the requirements to perform actions necessary to mitigate shutdownthe consequences of the event and to provide subsequent safe capability. These required actions are:

Reactor Trip Feedwater Isolation Safety Injection Actuation Auxiliary Feedwater Actuation Steam Line Isolation '

No other requirements exist or are necessary for component operation later in the event or during recovery operations other than those listed above.

, Attachment I

3) Determination that failure of the equipment after performance of its

! safety function will not be detrimental to plant safety or mislead the operator:

All essential components evaluated by Appendix E will remain in the required event mitigatiun or safe shutdown position and will not fail in such a manner as to mislead the operator or jeopardize the category lE bus regardless of the fact that they will be exposed to tempera-tures in excess of the qualified limits. The conclusion is based on Appendix E circuit analysis for primary and secondary component and control circuits and evaluation of electrical cable system integrity.

4) Determination that the margin applied to the minimum operability time, when combintd with the other test margins, will account for uncertain-ties. . . .:

BVPS-2 has addressed operability time margin for the superheated blow- '

down event by evaluating the ability of equipment to perform its l required safety function prior to steam generator tube uncovery (caus-ing superheat release) and prior to exceeding qualification levels of the equipment. In addition to the use of these time margins, further margin can be demonstrated in the development of the superheat envi-ronmental profiles published in 2BVM-119. The environmental profiles  ;

represent the worst case for safety signal generation time, peak tem-perature, and accident duration. Combining these f actors will account for. any uncertainties associated with the analytical techniques uti-lized to derive environmental parameters. '

Operability time margin is also inherent in the thermal lag analyses I i performed to determine component surface temperature response. As stated in Item 1 (break size spectrum), the energy release of 0.9 f t2  ;

i j break size is superimposed on the steamline isolation and blowdown 1

' termination times of the 0.4f t2 break size, thus providing inherent margin in the component surf ace temperature results.

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Attachm:nt II BVPS-2 Environmental Qualification Methodology for Submergence An original BVPS-2 plant design goal was to have all equipment associated with the Environmental Qualification (EQ) progran located above flood level during normal, abnormal and postulated accident conditions. This applies for the majority of the equipment in the BVPS-2 EQ program. This condition could not be entirely avoided and submergence qualification requirements were stip-ulated in the applicable equipment specification. In accordance with 10CFRSO.49, demonstration for submergence qualification includes testing as the principal means and/or analysis in combination with partial type test data.

Since development of the BVPS-2 specifications, the BVPS-2 internal compartment flooding analysis was completed to comply with Standard Review Plan 3.6-1 and 3.6-2. This analysis verified actual maximum flood elevations and determined the impact of flooded Class lE equipment on accident mitigation / safe i shutdown capability at BVPS-2. The results of this analysis were used to l define / verify equipnent which required qualification for cuomergence or for which submerged conditions were permissible due to equipment redundancy or com-pleted Class IE function. All such cases were reviewed and adequately documented within the applicable EQ packages.

In accordance with BVPS-2 Project Manual, 2BVM-128, all EQ progran equip-ment requiring qualification for submergence was reviewed considering the equipment function, location and operating time post accident. When submergence qualification was required, type test was the only acceptable methodology employed at BVPS-2 and often was supplemented with Engineering justification documented within the EQ package.

In addition, during the DLC review of the EQ package utilizing Engineering Instruction E103, the qualification methodology was again reviewed for acceptability to meet BVPS-2 applicable submergence conditions. As the result of the NRC/NRR EQ Audit comments, DLC is reviewing each applicable file to verify that the above methodology has been enployed.

In conclusion, BVPS-2 EQ progran equipment uses an adequate submergence qualification methodology. The documentation supporting this methodology is maintained within BVPS-2 EQ packages and meets the applicable requirements contained in 10CFR50.49.

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