ML20006A462
| ML20006A462 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 01/18/1990 |
| From: | Devincentis J YANKEE ATOMIC ELECTRIC CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20006A463 | List: |
| References | |
| BYR-90-006, BYR-90-6, NUDOCS 9001260289 | |
| Download: ML20006A462 (5) | |
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YANKEEATOMICELECTRIC COMPANY p
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January 18, 1990 BYR 90-006 United States' Nuclear Regulatory Commission
. Document Control Desk Washington, DC 20555
'Referencet
-(a) License No. DPR-3 (Docket No. 50-29)
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Subject:
' Technical Specifications Governing the Emergency Core Cooling System l
Dear Sirt Pursuant to Section 50.90 of the Commission's rules and regulations, the l
' Yankee Atomic Electric Company (YAEC) hereby requssts the authorization to make'the following changes
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Proposed Change e
Reference is made to the Technical Specifications of License No. DPR-3 of the Yankee Nuclear Power Station (YNPS). We propose to modify the license as followst'
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1.
Relocate surveillance requirements for Valve CH-MOV-524 from Section 4.5.2.b.1.b to Section 4.5.2.b.4.aa.
'2.
Revise valve function description in Section 4.5.2.b.4.k for Valve SI-MOV-46-from "High Pressure Safety Injection (HPSI) flow
. control" to "HPSI' isolation."
i 3.,
' Add surveillance requirements for new Valves SI-MOV-519, SI-MOV-520, and CH-MOV-550. Section 4.5.2.b.4.
j 4.
Add'Section 4.5.2.b.9'to verify that redundant HPSI header
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isolation / flow control valves are aligned to receive electrical power from separate operable buses.
o 5.
Add Section 4.5.2.b.10 to verify that redundant charging line isolation valves are aligned to receive power from separate operable I
~ buses.
6.
Add Section 4.5.2.b.11 to verify that redundant pressurizer auxiliary spray valves are aligned to receive power from separate operable buses.
Of 9001260289 900118 8
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. Uni,t;d St;t s Nucit r Regulct:ry ommicsion J;nuary 18, 1990
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t Attention: Document Control Desk Page 2 i
7.
Add Section 4.5.2.g.3 to require flow testing following modifications that alter the flow characteristics of the pressurizer auxiliary spray line.
Reason a:
t 3x is for Change i
These changes are being proposed to reflect modifications to the YNPS Emergency Core Cooling System (ECCS), Charging and Volume Control System (CVCS), and the Main Coolant Pressure Control System (PR), which are designed tot 1.
Enhance the plant's capability to control Main Coolant System pressure by providing redundant safety grade pressurizer auxiliary i'
spray capability, and 2.
Enhance post-LOCA sump recirculation flow control by providing redundant safety grade safety injection throttling capability.
Redundant motor-operated Pressurizer Auxiliary Spray Valves PR-MOV-548, 549 will be installed to replace the existing manually-operated valve.
This change is being implen.ented to provide enhanced safety grade auxiliary spray capability for periods when normal spray via the main coolant pumps is unavailable.
Initiation of auxiliary spray for Main Coolant System depressurization will require isolation of the normal charging line in order to direct the charging flow up to the pressurizer spray nozzle.
For this reason, a second series redundant Isolation Valve CH-MOV-550, located upstream of the Charging Line Isolation Valve CH-MOV-524, is required.
This arrangement will ensure that an auxiliary spray flow path will be available following any single active failure. Currently, CH-MOV-524 receives power via a normally open supply breaker. This breaker is open to preclude inadvertent valve closure during nornal plant operation and ensures a flow path for manual charging and post-LOCA hot leg recirculation.. Because CH-MOV-524 will require closure to initiate auxiliary spray, its power supply will be relocated, and a second series motor starter will be installed to preclude inadvertent valve closure
. due to single failure or operator error.
Either the charging pumps or the ECCS pumps can be utilized to provide the necessary flow to the auxiliary rpray line. When using the ECCS, flow is delivered via the hot leg injection subsystem. This subsystem provides a discharge path from the HPSI discharge line to the normal charging line for hot leg recirculation following large cold leg breaks.
The proposed ccheme for HPSI throttling is needed to establish flow to the pressurizer _ steam space for Main Coolant System pressure control when using ECCS for auxiliary spray. The existing ECCS alignment during cold leg recirculation results in injection through the single HPSI discharge line.
SI-MOV-46, located its the common HPSI header, is normally fully open during i-N -
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,a Unit:d States Nuclear R:gulat:ry Connissicn J:nuary 18, 1990
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Att'ention: Document Control Desk Page 3 V.
E the injection phase of system operation. The control circuit for this valve i:
is designed to preclude single active f ailures (closure) by electrical faults
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or operator error by incorporation of dual series contactors.
To ensure ECCS throttling capability, two additional Valves SI-MOV-519, 520 are required to accommodate all possible single-active valve failures. The proposed arrangement is shown on the attached Sketch A.
h An additional benefit from HPSI throttling includes the flexibility to.
reduce ECCS pump operation to a single HPSI pump during the recirculation phase of operation, thus significantly reducing emergency diesel generator loading. The decay heat. removal requirements during this period are well within the capacity of a single pump, and redundant safety grade system flow L
control will ensure that the pump is operated within its flow /NPSH limitations This design change will provide a significant degree of system operating flexibility and enhance long-term reliability of the ECCS pumps.
The addition of the new valves has been evaluated and determined to have negligible impact on ECCS performance.
Description of Chango The enclosed revised Technical Specification reflects the system biodifications described above.
Safety Considerations The piping systems affected by this modification are classified Safety Classes 1 and 2.
The electrical aspects of the modification are classified safety class.
-The modifications described will provide enhanced MCS pressure control and enhanced ECCS flow control.
It can be stated that:
1.
The probability of occurrence, the consequences of an accident, or the malfunction of equipment important to safety [r*"iously evaluated in the safety analysis is not increased.
The proposed modification will enhance the capability for controlling MCS pressure when the normal spray is unavailable.
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charging line will be isolated by series redundant isolation valves, and spray flow will be initiated through one of two parallel redundant flow control valves located in the spray line piping which i
L branches of f the nornal charging line.
This valve arrangement L'
ensures that spray flow can be initiated following any single active failure.
L Redundant safety grade HPSI discharge throttling capal.111ty will ensure that the required flow can be delivered to the pressurizer L
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' Q' United St:tts Nucle:r R:gulctcry Commission J:nuary 18, 1990 Att'ention: Document Control Desk Page 4 P
auxiliary spray line when using ECCS. This capability also provides the ficxibility to reduce ECCS pump operation to a single HFS1 pump during the recirculation phase of operation, thus significantly reducing the energency diesel generator loading.
The series redundant charging line valves will be provided with dual starter contactors to preclude spurious valve closure during normal plant operation. This feature provides assurance that the normal t
charging and ECCS hot leg recirculation path remains operable in accordance with existing Technical Specification requirements.
The addition of the new valves has been evaluated and determined to have negligible impact on ECCS performance.
Therefore, this change enhances MCS pressure control capabilities and provides an added degree of flexibility during normal cooldown, while preserving the existing design basis functional capabilities of the affected safety-related systems.
i 2.
The possibility for an accident or malfunction of a different type than any evaluated previously in the Safety Analysis Report is not created. The proposed auxiliary spray modification incorporates design features which enhance MCS pressure control capabilities-while not adversely impacting operation of any safety-related system's structures or components.
The design ensures that Main Coolant System depressurization can be accomplished in consideration of the limiting single failure and also precludes inadvertent charging line isolation during normal plant operation.
Inadvertent activation of auxiliary pressurizer spray would result in depressurization of the Main Coolant System.
This is not a credible event since multiple failures are needed to isolate the charging line and initiate auxiliary spray.
3.
The margin of safety as defined in the basis for any Technical Specification is not reduced.
-The charging line isolation modification is designed consistent with existing Technical Specification requirements which ensure that the charging line flow path remains operable during normal operation.
Based on the considerations contained herein, there is reasonable assurance that operation of the Yankee plant consistent with the proposed Technical Specifications will not endanger the health and safety of the public. This proposed change has been reviewed by the Nuclear Safety Audit and Review Committee.
Fee 1
l An application fee of $150.00 is enclosed in accordance with 10CFR170.21.
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g Uni,ted St:t:s Nuc10:r R:gulct:ry Ctmmissitn J:nuary 18, 1990 L
Attention Document Control Desk Page 5 L
Schedule of Change L
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These changes to the Yankee Technical Specifications are needed to l
support plant modifications scheduled for Cycles 20 and 21 refueling outage.
A timely review and approval of this submittal would be' appreciated.
We trust that you will find this submittal satisfactory; however, should you have any questions, please contact us.
t Very truly yours.
YANKEE ATOMIC ELECTRIC COMPANY J. DeVincentis Vice President BLD/b11/0502v Enclosure COMMONWEALTH OF MASSACHUSETTS)
)ss MIDDLESEX COUNTY
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Then personally appeared before me.J. DeVincentis, who, being duly sworn, did state that he is Vice President and Manager of Operations of Yankee Atomic Electric Company, that he is duly authorized to execute and file the foregoing document in the name and on the behalf of Yankee Atomic Electric Company and that the statements therein are true to the best of his knowledge and belief.
bl4A Robert 11. Groce Notary Public My Commission Expires August 29, 1991 l
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