ML20058D042
| ML20058D042 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 07/22/1982 |
| From: | Heider L VERMONT YANKEE NUCLEAR POWER CORP. |
| To: | Vassallo D Office of Nuclear Reactor Regulation |
| References | |
| FVY-82-87, NUDOCS 8207270013 | |
| Download: ML20058D042 (8) | |
Text
A VERMONT YANKEE NUCLEAR POWER CORPORATION 2.C.2.1 0-f RD 5, Box 169. Ferry Road, Brattleboro, VT 05301
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ENGINEERING OFFICE 1671 WORCESTER ROAD v
FRAMINGHAM, MASSACHUSETTS 01701 TEL E PHONE 617-872-8100 July 22, 1982 United States Nuclear Regulatory Commission Washington, D. C. 20555 Attention:
Office of Nuclear Reactor Regulation Mr. Domenic B. Vassallo, Chief Operating Peactors Branch No. 2 Division of Licensing
References:
(a ) License No. DFR-28 (Docket No. 50-271)
(b) Letter, VYNPC to USNRC, FVY 82-56, dated May 19, 1982 (c) letter, VYKPC to USNRC, FVY 82-68, dated June 8,1982
Subject:
Degraded Grid Voltage
Dear Sir:
The purpose of this letter is to forward the attached additional l
information as requested during a meeting held in Bethesda on June 17, 1982, i
and during a telecon held on June 25, 1982. This information was requested to supplement information submitted to you in References (b) and (c).
We t ru st that this information is acceptable; however, should you have further questions, please contact us.
Very truly yours, l
VERMONT YANKEE NUCLEAR POWER CORPORATION xpn3-1.C)l(3 L. H. Heider
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Vice President Enclosures 1
1 F207270013 820722 PDR ADDCK 05000271 P
PDR 1
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ADDITIONAL INFORMATION FOR VERMONT YANKEE In submitting the following additional information, Vermont Yankee Nuclear Power Corporation (VYNPC) understands that the review of the scheme for degraded grid voltage protection can te completed.
Beceuse the detailed design of the degraded grid voltage protection scheme cannot begin until NRC approval of our concept is received, the following information is preliminary.
(1) Two degraded grid undervoltage relays will be located on each 4160 volt safety bus.
The relays will be instantaneous undervoltage relays set at 92.5% +.1% of 4000 volts.
This setting assures that adequate voltage ex1rts at the terminals of al] safety related electric equipment fed from other buses. A ten second time delay is provided to prevent actuation during transients caused by motor starting or grid disturbances.
A schematic and one line representation of the undervoltage scheme is provided as Attachment 2.
The time delay will not exceed the time assumed in the FSAR accident analysis.
Tbc undervoltage system design will satisfy the requirements of IEEE 279-1971.
(2) Draft Technical Specifications are provided for information as Attachment 3.
Upon completion of the design change, final technical specification changes will be submitted.
(3) Vermont Yankee will comply with the NRC's position of by passing the load shed feature when the diesel generator breaker is closed and reinstatement of the load shed feature when the diesel generator breaker t ri ps. The design of the circuitry is not available at this time.
(4) Draf t Technical Specifications to demonstrate that upon interruption of the on site sources the loads are shed and subsequent hus loading is through the sequencer are provided in Attachment 2.
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j Attachm:nt 2 FIGURE I
TO OFFSITE POWER UNDERVOLTAGE SENSORS h
WPT1 MPT 2 )
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B-C
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EMERGENCY BUS l'
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ONE LiNE REPRESENTATION
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- d27A1
- TIME DELAY d
E 2781
- 27A2
- AhD T
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- f2781 5f27B2 $$
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BREAKER
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TIME i
TRIP
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DELAY Coll SCHEMATIC REPRESENTATION OF OFFSITE l
l POWER CIRCUIT BREAKER TRIP CIRCUIT
F VYNPS Attachm:nt 3 DRAFT TECHNICAL SPECIFICATIONS I. RECIRCULATION PUMP TRIP INSTRUMENTATION I. RECIRC PUMP TRIP INSTRUMENTATION During reactor power operation, the Recire Pump The Recire Pump Trip Instrumentation shall be Trip Instrumentation shall be operative in functionally tested and calibrated in accordance accordance with Table 3.2.1.
with Table 4.2.1.
J. LOSS OF POWER INSTREHENTATION J. LOSS OF POWER INSTRUMENTATION During reactor power operation, the Loss of Power Instrumentation shall be operative in accordance The Loss of Power Instrumentation shall be with Table 3.2.1.
functionally tested and calibrated in accordance with Table 4.2.1.
34a
VYNPS 9
TABLE 3.2.1 (CONT)
EMERGENCY CORE COOLING SYSTEM ACTUATION INSTRUMENTATION l
Automatic Depressurization i
Minimum Number of Operable Instrument Required Action When Minimum i
Channels per Trip Conditions for Operation are System (Note 4)
Trip Function Trip Level Setting not Satisfied 2
Low-Low Reactor Vessel Same as Core Spray Note 6 Water Level 2
High Drywell Pressure lE 2.5 psig Note 6 1
Time Delay (2E-KSA&B) 5E 120 seconds Note 6 l
1 Bus Power Monitor Note 6 Note 6 1
Trip System Logic Loss of Power 2
Degraded Bus Voltage - Voltage 3700 volts + 40 volts Note 2 Time 10 sec + 1 sec l
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VYNPS TABLE 4.2.1 (CONT)
Automatic Depressurization System Functional Test (8)
Calibration (8)
Instrument Check Trip System Low-Low Reactor Vessel Water (Note 1) once/ operating cycle once each day Level (Note 1) every 3 months High Drywell Pressure once each day (Note 1)
None Bus Power Monitors every 6 months every 6 months Trip System Logic (except solenoids of valves)
(Note 2)
(Note 3) l Loss of Power Monthly once/ operating cycle
- Degraded Bus Voltage 53
VYNPS 4.10 SURVEILLANCE REQUIREMENTS 3.10 LIMITING CONDITIONS FOR OPERATION b.
The undervoltage automatic starting circuit of each diesel generator shall be tested once a month.
c.
Once per operating cycle, the actual conditions under which the diesel generators are required to start automatically will be simulated and a test conducted to demonstrate that they will start within 13 seconds and accept the emergency load and start each load within the specified starting time. The re-instatement of the load shed feature upon tripping of diesel generator breaker will also be tested. The results shall be logged.
2.
Batteries 2.
Batteries The following battery charges shall be operable:
a.
Every week the specific gravity Four battery chargers for the +24 a.
volt neutron monitor and process and voltage of the pilot cell and radiation batteries.
temperature of adjacent cells and overall battery voltage shall be measured and logged.
b.
Two of the three battery chargers b.
Every three months the voltage of for the 125 volt station each cell to nearest 0.01 volt and specific gravity of each cell batteries.
to the nearest 0.005 ap.gr. shall be measured and logged.
174
VYNPS 3.10 LIMITING CONDITIONS FOR OPERATION 4.10 SURVEILLANCE REQUIREMENTS c.
One of the two battery chargers c.
Once each operating cycle each for the 125 volt switchyard station 125 volt battery shall be batteries, subjected to a rated loud discharge test. The specific gravity and voltage of each cell shall be measured after the discharge test and logged.
l d.
Two of the three battery chargers for the 24 volt ECCS j
Instrumentation.
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t 174a