ML20236H422
| ML20236H422 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 06/30/1998 |
| From: | Barkhurst R VERMONT YANKEE NUCLEAR POWER CORP. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20236H424 | List: |
| References | |
| BVP-98-15, NUDOCS 9807070205 | |
| Download: ML20236H422 (6) | |
Text
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VERMONT YANKEE
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NUCLEAR POWER CORPORATION
. 185 Old Ferry Road, Brattleboro, VT 05301-7002 (802) 257-5271 June 30,1998 BVY 98-15 United States Nuclear Regulatory Commission A'ITN: Document Control Desk Washington, DC 20555
Subject:
Vermont Yankee Nuclear Power Station License No. DPR-28 (Docket No. 50-271)
Technical Specification Proposed Change No.199 Revision to Emernency Core Cooline Actuation Instrumentation Tables 4.2.1 for: Core Sgray System and Low Pressure Coolant Iniection System for the Auxiliary Power r
Monitor Function In accordance with 10CFR50.90, Vermont Yankee Nuclear Power Corporation (VYNPC) requests that Appendix A of the Facility Operating License be amended to modify the Vermont Yankee Technical Specifications to delete the Emergency Core Cooling Actuation Instrumentation - Core Spray System and Low Pressure Coolant Injection System Auxiliary Power Monitor calibration requirement.
VYNPC has determined that the proposed license amendment does not involve a significant hazards consideration pursuant to 10CFR50.92. A description of the amendment request is provided in.
The no significant hazards determination in support of the proposed Technical Specification change is provided in Attachment 2. Attachment 3 provides the proposed marked up copies of the Technical Specifications pages. Attachment 4 provides the revised new Technical Specification Pages.
The proposed license amendrnent has been reviewed by the Vermont Yankee Plant Operations Review Committee (PORC) and the Nuclear Safety Audit and Review Committee (NS ARC).
Should there be any questions pertaining to this request, please contact this office.
Sincerely, Vermont Yankee Nuclear Power Corporation Ross P. Barkhurst Preeident & Chief Executive Officer DI D
ADOCK 05000271[
9807070205 980630 PDR p
VERMONT Y ANKEE NUCLEAR POWER CORPORATION
- Docket No. 50-271
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BVY 98-15 Page 2 of 2 Attachments cc:
USNRC Region 1 Administrator USNRC Resident Inspector-VYNPS gr
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USNRC Project Manager-VYNPS
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VT Department of Public Service NOTAR) r, e l
FUBUC A c 4J STATE OF VERMONT WINDHAMCOUNTY )
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'Iben personally appeared before me, Ross P. Barkhurst, who, being duly sworn, did state that he is President & Chief Executive Officer, of Vermont Yankee Nuclear Power Corp 4ation, that he is duly authorized to execute and file the forgoing document in the name and on behalf of Vermont Yankee Nuclear Power Cogoration, and that the statements therein are true to the best of his knowledge and belief.
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/f.. h Sally A S4ndstnun, Notary Public My Commission expires February 10,1999 l
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VERMONT YANKEE NUCLEAR POWER CORPORATION
' Docket No. 50-271 BVY 98-15 Page 1 of 2 ATTACHMENT 1 DESCRIPTION OF AMENDMENT REOUEST nis proposed change revises Technical Specifications (TS) to: 1) eliminate the Core Spray System Auxiliary Power Monitor function Refueling Outage calibration requirement, and 2) eliminate the Low Pressure Coolant Injection System Auxiliary Power Monitor function Refueling Outage calibration requirement.
Specifically, the changes proposed are as follows:
- 1) T.S. Table 4.2.1 Emergency Core Cooling Actuation Instrumentation - Core Spray System, page 59:
. Delete the " Auxiliary Power Monitor" function " Refueling Outage" calibration requirement.
- 2) T.S. Table 4.2.1 Emergency Core Cooling Actuation Instrumentation - Low Pressure Coolant Injection l
System, page 60: Delete the " Auxiliary Power Monitor" function " Refueling Outage" calibration requirement.
Reason / Bases For Channe:
The Core Spray Auxi?iary Power Monitor relays (14A-KIA/B) and Low Pressure Coolant Injection Auxiliary Power Monitor relays (10A-KIA/B) are auxiliary relays which are actuated by logic relays LNPX-C and LNPX-D in the Diesel Generator DG-1-1 A/B breaker logic. On a Loss of Coolant Accident (LOCA) signal concurrent with a loss of normal power (LNP), the LNP logic relays (LNPX-C/D) cause de-energization of the Auxihary Power Monitor relays (14A-KI A/B,10A-KI A/B) which in turn, prevent starting of the B and C Residual Heat Removal (RHR) Pumps and the two Core Spray (CS) Pumps until their respective time delay relays time out. The Auxiliary Power Monitor function ensures sequential starting ofloads on the emergency diesel generators when the diesels have re-powered their respective emergency buses With normal power available, the Auxiliary Power Monitor relays remain energized and allow all RHR and CS pumps to start at the time of the LOCA signal.
1 He Auxiliary Power Monitor relays are General Electric Type HFA151A or HGAllA multi-contact auxiliary logic relays, not time delay or undervoltage relays which require a specific trip setting. These relays are the same type relas used throughout the Emergency Core Cooling Systems (ECCS) and Reactor Protection System (RPS) without a requirement existing for a " calibration" surveillance. He HFA151A relay is self resetting and has an instantaneous dropout and adjustable pickup voltage. The HFA relay is factory adjusted to pick up at 55% to 61% of ratmg for DC coils and normally should not
~ change. De HGA relay is self resetting and has a single adjustment for pickup and dropout and is adjusted by the manufacturer to pickup at 50 to 60 percent of rating when cold (DC coils). Following warmup, the HGAl1 A relay pickup and dropout voltages increase 5 to 10 percent. With either relay, the pickup and dropout voltages are well below the allowable voltage variations for the supply that powers the relays. Although adjustment of the relay pickup voltage is possible, this adjustment requires disassembly of the relay and therefore is not routinely performed.
He Auxiliary Power Monitor functions of Technical Specifications Table 3.2.1 CS/LPCI do not require a Trip Level. setting as the relays operate from a switched input, either ON or OFF (power available-relay
VERMONT YANKEE NUCLEAR POWER CORPORATION
" Docket No. 50-271 BVY 98-15 Page 2 of 2 energized or power not available-relay de-eneigized). Functional testing is sufficient to demonstrate the relay pickup / dropout capability.
"Ihc CS and LPCI Auxiliary Power Monitor relays are required to be functionally tested monthly using installed test switches. In addition, the Auxiliary Power Monitor function is tested in its entirety (primary sensor to sensor relay and associated contacts) during the Trip System Logic and Integrated ECCS Tests performed each refueling Outage. A calibration requirement serves no " operability verification" purpose for an instantaneous dropout auxiliary logic relay. The combination of the functional and logic testing performed provide the required "OPERABII ITY" demonstration.
J Safety Considerations
- Ihe safety function of the CS and LPCI Auxiliary Power Monitors is to initiate logic on a Loss of Normal Power (LNP) to provide sequential starting of the RHR and Core Spray Pumps on the Emergency Diesel Generators (EDGs). Part of the Auxiliary Power Monitors function is to allow the immediate start of the
- four RHR and both CS Pumps if normal power is available. The only delay is the inherent operating time for the pump auto start relay circuit. If the relay pickup did not occur, the RHR and CS pumps would start in the same sequence as with normal power not available and provide the required cooling for the LOCA l
condition.
4 The definition of INSTRUMENT CALIBRATION is: "An instrument calibration means the adjustment of an instrument signal output so that it corresponds, within acceptable range and accuracy, to a known value(s) of the parameter which the instrument monitors". 'Ihe parameter monitored is a switched input and not variable, therefore, for a logic relay, an instrument calibration of the relay pickup voltage setpoint does not provide any additional operability validation.
Operability of the CS and LPCI Auxiliary Power Monitor functions is demonstrated through the required Functional Test and Trip System Logic Test required by Technical Specification Table 4.2.1 for each function and the Simulated Automatic Actuation Test of Specification 4.5.A.I.a. "Ihe Auxiliary Power i
Monitor relay pickup / dropout capability is verified by performance of the Functional test and the total circuit is tested under the logic testing performed each re. fueling outage. The only change is that a calibration will not be required for these auxiliary logic relays. The demonstration of the RHR and CS pump instantaneous and delayed startmg logic within the times necessary to meet the LOCA analysis of record provides' assurance of operability of the Auxiliary Power Monitor function. An instrument calibration is not necessary. To perform an instrument calibration (by the definition) introduces personnel electrical safety risk of working in energized equipment when not required.
VERMONT YANKEE NUCLEAR POWER CORPORATION Docket No. 50-271 BVY 98-15 Page 1 of 2 ATTACHMENT 2 NO SIGNIFICANT HAZARDS CONSIDERATION DETERMINATION -
He standards used to determine that a request for amendment involves no significant hazards are -
included in 10CFR50.92 of the Commission's rules and regulations. %ese standards state that operation of the facility in accordance with the proposed amendment would not: (1) involve a significant increase in the probability or consequences of an accident previously evaluated; or (2) create the possibility of a new or different kind of accident from any accident previously evaluated; or (3) involve a significant reduction in a margin of safety.. He discussion below addresses each of these criteria and demonstrates that the propased amendment does not constitute a significant hazard.
I 1.
The nronosed amendment will not involve a mionifbat incr-e in the probability or conecmenm of an RCAdentDreviousiv eval-a a-ne proposed change does not involve a change to the plant design or operation. He Auxiliary Power Monitor logic relays installed are tested to fully demonstrate operability without performance of a calibration on the pickup voltage value. The design intent of the relays is to l
start LPCI and CS pumps as soon as possible without causing loss of the normal or emergency I
power supplies and within the time frames specified in the LOCA analysis of record. He proposed change does not affect any of the parameters, or conditions that contribute to initiation
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of any accidents previously evaluated. Hus, the proposed change cannot increase the probability of an accident previou:ly evaluated.
L The proposed change does not involve a change in the operation of the relays controlling RHR and CS Pump start with normal power available nor the initial RHR pump start on a LOCA with L
normal power not available or the time delay start of the remaining RHR or CS pumps with j
normal power not available. Failure of the relays to pickup would still result in the stant sequence 1
l for normal power not available. He logic for both start sequences is verified independent of an I
instrument calibration and is consistent with the LOCA analysis and the EDG load analysis, l
therefore, the proposed change does not significantly increase the consequences of any accident i
previously evaluated.
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He crocosed amendment will not create the possibility of a new or different kind of accident l
from any oreviously evaluated:
nis proposed change will not involve any physical changes to plant systems, structures or components (SSC), or the manner in which these SSCs are operated or maintained. He calibration requirement has previously been considered to be met by performance of the Simulated Automatic Actuation Test. Deletion of the calibration requirement will not affect the RHR or CS Pumps startmg on a LOCA signal, with or without an LNP. The operability of the Auxiliary Power Monitor relays will still be tested under the Functional test and Trip System Logic and Simulated Automatic Actuation tests at the frequencies specified. Herefore, this change will not create the possibility of a new or different kind of accident from any accident previously evaluated.
VERMONT YANKEE NUCLEAR POWER CORPORATION l.
f Docket No. 50-271 BVY 98-15 Page 2 of 2 3.
The proposed amendment will not involve a significant reduction in the marnin of safety:
This proposed change to delete the calibration requirement for the CS and LPCI Auxiliary Power Monitor functions will not change operation of the RHR or CS Pump start sequences on a LOCA signal, with or without normal power available. The instantaneous logic sequence relays and time delay relays will function to initiate RHR and CS Pump start as designed. RHR and CS Pump start times will remain within the LOCA Safety Evaluation of record. Operability of the relays and associated circuluy are still demonstrated by the Functional test and associated Trip Symm
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logic and Simulated Automatic Actuation tests. Threfore, this change does not involve a significant reduction in a margin of safety.
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