ML20235H540

Application for Amend to License DPR-36,consisting of Proposed Change 146,amending Tech Spec Sections 3.9 & 4.1 to Add Primary Inventory Trend Sys for Reactor Vessel Level Indication & Core Exit Thermocouples Channel Operability

ML20235H540
Person / Time
Site:	Maine Yankee
Issue date:	02/15/1989
From:	Frizzle C Maine Yankee
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20235H544	List: ML20235H540 ML20235H558
References
CDF-89-17, MN-89-17, NUDOCS 8902230642
Download: ML20235H540 (5)

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MaineYankee-RELIABLE ELECTRICITY FOR MAINE SINCE 1972 EDISON DRIVE . AUGUSTA, MAINE 04330 . (207) 622 4868 February 15, 1989:

HN-89-17 l10CFR50.90l Proposed Change No. 146-p, CDF-89-17 i

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United States. Nuclear Regulatory Commission LAttention: Document Control Desk Hashington, D.:C. 20555

References:

(a) License.No. DPR-36 (Docket No. 50-309) . . .

(b). Maine Yankee Inadequate Core Cooling Instrumentation Design and' Accuracy Report'(MN-88-33) dated March 28, 1988' (c) USNRC Letter to MYAPCo dated July 7, 1988, Safety Evaluation for the Inadequate Core Cooling System S'ubject: Proposed Change No. '146 - Primary Inventory Trend System and Core Exit Thermocouple' Technical Specification- ,

Gentlemen:

Maine Yankee hereby-submits, pursuant to 10 CFR 50.90, this application.to amend Sections 3.9 and 4.1- of the Technical Specifications to our operating license.

Thi.s amendment request would modify Table 3.9-3, Accident Monitoring Instrumentation, and Table 4.1-3, to add the Primary Inventory Trend System (PITS) for reactor vessel level indication and core exit thermocouple (CET) channel operability and surveillance requirements to the Technical Specifications. Also, minor. editorial changes 'are proposed to Tables 3.9-3 and 4.1-3 as described in Attachment A.

Maine Yankee has evaluated the proposed changes and has determined that they do not involve a significant increase in the probability or consequences of an accident previously evaluated; increase the possibility of a new or different kind of accident from any accident previously evaluated; or involve-a significant reduction in a margin of safety. Therefore, these proposed changes do not. include a significant hazards consideration as defined in 10 CFR 50.92. The evaluation is presented in Attachment A.

The proposed changes to the Technical Specifications are presented in Attachment 8.

These proposed changes have been reviewed by the Plant Operation Review Committee and the Nuclear Safety Audit and Review Committee. The Plant Operations Review Committee has concluded that the proposed Technical pl p

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Specification changes do not constitute an unreviewed safety question. (6 8902230642 890213 P Nl T hDR ADOCK 05000309 F'DC g ii j 0641L-SDE

MaineYankee United States Nuclear. Regulatory Commission Page.Two Attention: Document Control Desk MN-89-17 l

l A State of Maine representative has been sent a' copy of this proposed i change. A license amendment application fee of $150.00 is enclosed per 10 CFR 50.71.

He request that this amendment become effective ninety (90) days following, NRC approval of the system installation, as indicated by the Attachment to Reference (c).

Very truly yours, MAINE YANKEE n

Charles D. Frizzle President JBR/bjp Attachment c: Mr. Richard H. Nessman Mr. Hilliam T. Russell Mr. Cornelius F. Holden Mr.' Patrick M. Sears Mr. H. Clough Toppan, Maine Department of Human Services STATE OF MAINE Then personally appeared before me, Charles D. Frizzle, who being duly sworn did state that he is President of Maine Yankee Atomic Power Company, that he is duly authorized to execute and file the foregoing request in the-name and on behalf of Maine Yankee Atomic Power Company, and that the statements therein are true to the best of his knowledge and belief.

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MaineYankee l ATTACHMENT A Description of Prooosed Chanae The final design and accuracy evaluation of the Inadequate Core Cooling Instrumentation (ICCI) System was described to the NRC in a letter dated March 28, 1988, Reference (b). The NRC determined, in the July 7, 1988 Safety Evaluation, Reference (c), that the Maine Yankee ICCI System as described in Reference (b), complies with the requirements of Item II.F.2 of NUREG-0737.

This proposed change adds two ICCI subsystems - the Primary Inventory Trend System (PITS) and the Core Exit Thermocouple (CET) System - to the Technical Specifications as required by NUREG-0737. The third ICCI subsystem - the Saturation Margin Monitor (SMM), is already included in the Technical Specifications (Tables 3.9-3 and 4.1-3) (formerly listed as Subcooling Margin Monitor). The upgrade to the PITS was completed during the October-December 1988 refueling outage.

Two minor edi' orial changes are also proposed in Tables 3.9-3 and 4.1-3:

(1) " Auxiliary Feedwater Flow Rate" has been changed to " Emergency Feedwater Flow Rate" to reflect proper system nomenclature.

(2) " Reactor Coolant System Subcooling Margin Monitor" has been changed to " Reactor Coolant System Saturation Margin Monitor" for consistency with design basis documents.

Primary Inventory Trend System (PITS)

The PITS uses differential pressure measurements to indicate collapsed liquid level in the reactor vessel during a small break incident when the coolant pumps are not operating. The system consists of redundant, independently powered channels using environmentally-qualified differential pressure transmitters to measure hydrostatic head between the top and bottom of the reactor vessel. A common impulse line is used for both channels. The top portion of the line (reference leg) is connected to a reactor head flange and the bottom portion of the line (variable leg) is connected to an incore instrument guide tube below the vessel in the instrument sump. The measurement height from top to bottom of the vessel is 41.25 feet. A seal pot at the top of the reference leg provides a reservoir for thermal expansion and contraction of the reference leg water and for displacement of dissolved gasses. Density compensation for fluid in the vessel and in the impulse. line is provided by CET temperature measurements, pressurizer pressure, and RTDs on the vertical runs of impulse line.

The differential pressure transmitters, which input directly to their associated channel microprocessors, are located in the outer annulus of the containment building at an elevation above the design basis containment flood level. The Rosemount 1154D dp transmitters are seismically and environmentally qualified to IEEE Standards 344-1975 and 323-1974.

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-2 The vessel level computed by the microprocessors is displayed on Sigma

! indicators on the main control board vertical section C for each PITS l channel. Each indicator is scaled to read from 0 to 100% reactor vessel static level without reactor coolant pumps on. Trending of vessel level is provided by strip chart recorders located in the auxiliary logic cabinets in the control room. In addition, isolated signals are provided to the SPDS which displays level and twelve minutes of trend. Historical data beyond twelve minutes can be provided via hign speed printers in the Control Room and Technical Support Center.

Core Exit Thermocouple (CET) System The Core Exit Thermocouple system consists of a minimum of 39 CETs (Core

10) distributed throughout the core at the fuel alignment plate elevation.

The primary display consists of two different core maps; one available on demand via printers located in the Control Room, and the second via the SPDS.

The SPDS is a CRT display which shows all CET locations and temperatures.

CETs for the two SMM trains are color-coded for easy identification. Average core temperature, highest core temperature and trending of CET temperatures are also displayed on the SPDS.

Sixteen qualified CETs, two per quadrant per channel, are connected to the SMM trains and indicators on the main control board for backup display. A selector switch on each channel allows rapid checking of each CET. The two channels are redundant, independent trains energized from separate Class 1E power supplies. The backup display is available at all times during operation and has been incorporated into the plant emergency procedures.

Significant Hazards Evaluation The proposed changes described herein have been evaluated against the standards in 10 CFR 50.92 and it has been determined that operation of the facility in accordance with the proposed amendment would not involve a significant hazards consideration. These proposed changes would not:

1. Involve a significant increase in the probability or consequences of an accident previously evaluated.

The PITS is designed to indicate collapsed liquid level in the reactor vessel during a small break incident after the reactor coolant pumps (RCPs) are shut off. The PITS provides no automatic actuation or control functions and, therefore, will not impact the probability of previously analyzed accidents. Incorporation of the PITS into the Technical Specifications may decrease the consequences of certain accidents previously analyzed by implementing instrumentation designed to provide additional information to the operator to detect the approach and to aid in the response to

-inadequate core cooling conditions.

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2. Create the possibility of a new or different kind of accident from any previously evaluated.

The proposed change involves specifying the operability and surveillance requirements for existing and redesigned accident

. monitoring instrumentation and, therefore, does not create the possibility of any new'or different kind of accident.

.3. Involve a significant' reduction in a margin of safety.

Inclusion of operability and sur'veillance requirements for PITS and CETS in the Technical Specifications may. increase the margin of safety by providing reasonable assurance that the instrumentation available to be used by. operators in responding to and assessing recovery actions to certain accidents and abnormal conditions are periodically maintained and operable for specified operating modes.

Maine Yankee has concluded that the proposed' changes to the Technical Specifications do not involve a significant hazards consideration.

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