ML20071E588

Forwards Response to NRC 820802 Request for Certain Design Info Re Reactor Protection Sys Power Monitoring Sys Mod. Proposed Tech Specs Will Be Forwarded Under Separate Cover

ML20071E588
Person / Time
Site:	Vermont Yankee
Issue date:	02/15/1983
From:	Sinclair J VERMONT YANKEE NUCLEAR POWER CORP.
To:	Vassallo D Office of Nuclear Reactor Regulation
References
FVY-83-13, NUDOCS 8303150292
Download: ML20071E588 (4)

Text

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. s VERMONT YANKEE NUCLEAR POWER CORPORATION 2.C.2.1

. RD 5, Box 169, Ferry Road Brattleboro, VT 05301 ncety To: FVY 83-13 g

g ENGINEERING OFFICE 1671 WORCESTER ROAD FRAMINGH AM, MASSACHUSETTS 01701 February 25, 1983

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United States Nuclear Regulatory Commission Washington, D. C. 20555 Attentfan: Office of Nuclear Reactor Regulation -

Mr. Domenic B. Vassallo, Chief Operating Reactors Branch No. 2 Division of Licensing

References:

(a) License No. DPR-28 (Docket No. 50-271)

(b) Letter, USNRC to VYNPC, NVY 82-124, dated August 2, 1982 (c) Letter, USNRC to General Electric Co., dated Februsry 23, 1979 -

Subject:

Reactor Protection System (RPS) Power Supply

Dear Sir:

Reference (b) requested Vermont Yankee to provide you with certain design information regarding the Reactor Protection System (RPS) Power Monitoring System Modification. Reference (b) also forwarded, for our consideration, model Technical Specifications for RPS electric power monitoring.

The requested design information is provided in Attachments I and II. We have considered the proposed Technical Specifications and will forward a proposed change under separate cover.

We trust that this information is acceptable; however, should you have any questions, please contact us.

Very truly yours, VERMONT NUCLEAR POWER CORPORATION

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.6. LAP J. B. Sinclair Licensing Engineer JBS/jmb

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F303150292 830215 '

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ATTACHMENT I February 25, 1983-Page 1 RESPONSES TO NRC REQUEST.FOR DESIGN INFORMATION:

1) , Request: Submit detailed. drawings of the proposed design modification to the MonitoringfSystem for the RPS power supplies (MGs and alternate tource). The drawings should include component ratings, and schematic and wiring diagrams.

Responsi: Specifications are provided in Attachment II. The applicable drawings can be made available to you at our Engineering office.

2) ~ Request,: Submit a current revisica of the electrical one-line diagram of the On-Site Distribution System and a schematic / elementary disgrem that includes the RPS power distribution buses..

.Responee: One-lioe dingzams of the On-Site Distribution System may be focnd *.n-Section 8.2 of the Vermont Tankee Final Safety- i 1 Analysis Feport (FSAR). Additionsl drawing can be made p' available to you at our Engineertr4g office.

[ 3). 3eguest: Provide justitic.ation that propored-cime delays, if any, will nut resul?. in damage to RPS System components or affect the-1 performance of required safety functions.

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Response: Each ulectrical Protection Assembly (EPA) is provided with three independent time delay circuits, one each for-

+ undervoltage, overvoltage, and underfrequency. These are adjustable,from approximately 0.1 to 3.0 seconds.  ;

The time delay setting for the undervoltage monitoring circuit will be set at its maximum setting of approximately 3.0 seconds. This setting should avoid any nuisance tripping of the'RPS due to transients and will not cause any damage to RPS components or affect RPS performance. We consider only-sustained undervoltage as potentially damaging.

The time delay settings for the underfrequency and

, overvoltage monitoring circuits will be set at their minimum setting of approximately 0.1 seconds. With this minimum time 5 delay, RPS components will not.be subjected to transients outside the normal voltage and frequency range for any longer than dictated by the trip circuitry design.

!! 4) Request: Provide justification-that the design modification and components will meet the requirements of GDC 2 and-GDC 21 of 10CFR Part 50, Appendix A.

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Re sponse : Vernont Yankee is installingi the General Electric Reactor Protection System Circuit' Upgrade package. ' The concepiual

^ . desigit of thi.s package was presented to the NRC by General

'alectric for' approval. The NRC letter to General Electric, Refeb3nde (c) of tbd cover letter, stat $d that the- . -

modif1'ation will. bring \ the overall P.PS design into fullc

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' ' . Eoaforhance with Criteria 2 and 21 of the General Design Criteria. , 4

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5) RequestE Specify Monitoring' System-overvoltage, undervoltage, and

, underf requency tri; T =tpoints.

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4, j Re,slonse: _t is aniticipated that the following trip setpoints vii.1 be used:

Overvol tage: +.101 of nocinal 120 V ae '

"Undervoltage: - '10% of nominal 120 V ac h' Underfrequency: - 5% of nouinal 60 Hertz ,

6) Request: Confirm that celected, setpoints with time delays are based on the measured terminal vcitage on the RPS components, including scram p120t sofeosid valves, and will ensure rated

- voltage and,frequene on che terminals of ench'of these components. ,E -

N Response: Vermont Yankee has measuredthe terminal voltage on several RPS components, including solenoids, during normal operation. Based ,an these measurements and the 'xpected- e operation of each Electrical Protection Assembly monitoring H l . circuit, we conclude that rated voltage and frequency will be >

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, . . c, ATTACHMENT II February 25, 1983 Page 1 SPECIFICATIONS

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Following are the specifications to which the equipment was manufactured.

These specifications meet or exceed Vermont Yankee's requirements.

1. ELECTRICAL .

Nominal Voltage Range: 120 V ac (+2%)

Current Requirements:

Startup Current: 280 mA for one second Running Current: 250 mA Single Phase: Two Wire (plus ground)

Frequency: 50 hertz (Hz)/60 Hz Tine Delay: Continuously adjustable from approximately 0.1 to 3.0 seconda

,. Circuit Breaker Max Load: 175 amperes ac

2. OPERAIING Teuperature: 400F to 1370F

-Humidity: Up to 95% Relative Radiation: 2x104 RAD, Silcon Total Integrated Dose (TID) Group I 2x105 RAD, Silcon Total Integrated dose (TID) Group II Altitude: 0 - 10,000 feet above sea level

3. . MECHANICAL Weight: 60 pounds.

Height: 20 inches Depth: 8 inches Width: 16 inches 4 SEISMIC

a. Operating Base Earthquake-(OBE) 5.0 (G)

b. Safe Shutdown Earthquake (SSE) 7.0 G C. Frequency Spectrum 1 to 33 Hz i

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