ML20086H699

Tech Spec Change Request 209 to License DPR-50,revising Definition for Heat Balance Calculation & Deleting Need for Reactor Shutdown on Loss of One Redundant narrow-range Containment Water Level Instrument

ML20086H699
Person / Time
Site:	Three Mile Island
Issue date:	12/03/1991
From:	Broughton T GENERAL PUBLIC UTILITIES CORP.
To:
Shared Package
ML20086H698	List: ML20086H695 ML20086H699 ML20086H701
References
NUDOCS 9112090302
Download: ML20086H699 (6)

Text

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METROPOLITAN EDIS0N COMPANY

-JERSEY CENTRAL POWER & LIGHT COMPANY AND PENNSYLVANIA EliCTRIC COMPANY THREE MILE ISLAND NUCLEAR STATION, UNIT l-Operating License No. DPR-50 Docket No, 50-289 Technical Specification Change Request No. 209 This Technical Specification Change kequest is submitted in support of Licensee's request to a change to Operating License No. DPR-50 for Three Mile Island Nuclear Station, Unit 1. As a part of this request, proposed replacement page(s) are included.

GPU NUCLEAR CORPORATION gy: Il%

Vice President and Director, TMI-l Sworn and Subscribe 6 to before me this J1M day of MNW>N/J/L ,1991.

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Notary Public t*nd s.a

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summm n uG3 FDR ADOCK 05000259 F' POR l

l UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISS)^N 1

IN THE MATTER OF DOCKET NO 50-289 GPU NUCLEAR CORPORATION LICENSE N0. DPR-50 1

CERTIFICATE OF SERVICE j This is to certify that a copy of Technical Specification Change Request No.

209 of the Operating License for Three Mile Island Nuclear Station Unit 1, has, on the date given below been filed with executives of Londonderry Township, Dauphin County, Pennsylvania; Dauphin County, Pennsylvania; and the Pennsylvania Department of Environmental Resources, Bureau of Radiation Protection, by deposit in the United States mail, addressed as follows:

Mr. Jay H. Kopp, Chairman Ms. Sally S. Klein, Chairman Board of Supervisors of Board of County Commissioners Londonderry Township of Dauphin County R. D. #1, Geyers Church Road Dauphin County Courthouse Middletown, PA 17057 Harrisburg, PA 17120 -

Mr. Thomas Gerusky, Director PA. Dept. of Environmental Resources Bureau of Radiation Protection P.O. Box 2063 Harrisburg, PA 17120 i GPU NUCLEAR CORPORATION BY: -% dd~

Vice President & Director, THI , DATE: Deceber 3,1991 r

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1. TECHNICAL SPECIFICATION CHANGE RE0 VEST N0. 209 GPUN requests that the attached revised pages replace 1-4, 3-40d and 3-40e of the TMI-l Technical Specifications and 1-4a be deleted.

11. Reasons for the Chana n This request involves two changes to the Technical Specificaticn (TS).

The purpose of the first change, which is administrative, is to revise the definition for a Heat Balance Calibration as identified on page 1-4 of the TS. The change deletes from the definition the primary and secondary heat balance weighting formulae for determination of core thermal power.

The purpose of the second change is to delete the need for a reactor shutdown on loss of one of the redundant narrow range Containment Water Level instruments. To accomplish this, the information presented in TS Table 3.5-3, Accident Monitoring Instrumentation, is clarified by indicating the existing Containment Water level instrumentation hardware configuration. Page 3-40d, containing the table, has been revised to indicate that the Containment Water Level instrumentaticn consists of two redundant channels. A channel consists of two similar transmitters; one each for the narrow and wide range (sump and containment flood level) instrument in the channel. Tag numbers for the sump and flood level instruments are listed separately to indicate the existing hardware configuration, in particular the redundant narrow range instrumentation. Listing the instruments individually permits the identification of the number of channels of narrow and wide range instruments that should be in operation consistent with item (8) in the Sti.ff Guidance on TS for NCREG 0737 and allows separate action statements for the two instrumentation ranges.

Page 3-40e is revised to indicate an action "C" required for an inoperable containment sump level instrument.

Ill. Safety Evaluation Justifyina the Proposed T.S. Chanae The heat balance is used to calibrate the nuclear lastruments and to confirm operation within the rated thermal power specified in the license as defined by TS section 1.1, " Rated Power " GPUN has chosen to retain a definition of Heat Balance Calibration in the TMI-l TS even though, NUREG-0103, Standard Technical Specifications for Babcock and Wilcox Pressurized Water Reactors, no longer lists it as a " defined term." Change one deletes unnecessary information from the definition for Heat Balance Calibration by limiting its content to a statement of the meaning of the term. The change clarifies that an unreviewed safety question does not exist if future change to the Heat Balance determination eliminates the Heat Balance weighting factors.

As operational experience accumulated. it became apparent that the additional specification of a core thermal power determination by weighting prin'ary and secondary heat balances was not warranted.

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TSCR 209 Furthermore, the additional specification of weighting heat balances to determine core thermal power is not included in Standard Technical Specifications.

The THI-l FSAR identifies the maximum allowable contribution to the maximum power level measurement error which may result from a heat balance error as less than or equal to 2%. The limitation remains unchanged by this revision of the TS.

The second change proposes deletion of the present requirement to restore a sump-level instrument to service or shutdown the unit _on loss

-of one or both of the redundant narrow range (sump) level instruments.

The proposed action would restore sump level instrumentation to service during.the first cold shutdown following-its inoperability declaration.

This meets the requirements of NUREG 0737 section ll.F.1.5. which requires that "At least one channel for narrow range and two channelt for wide range instruments should be operable at all times when the reactor is operating...." The change is considered justified for THI-l for the following reasons:

1) Unlike later containment sump designs, the TMI-l sump is small (approximately 9200 gallon capacity) and intended for collection of leakage occurring during normal plant operations. It also acts as a low point suction for the Decay Heat Removal pumps and the Reactor Building Spray pumps. The sump has insufficient capacity to be considered a water source since an accumulation of water in the Reactor Building containment is necessary to provide adequate net positive suction head to the pumps. The accumulated water in the Reactor Bui; Jing is the measurement of interest during and following an accident and is measured by the redundant wide range l Containment Water Level instruments.

2) The containment narrow range level instruments are identified as -

Reg Guide 1.97, Category 2. Although they are classified as safety-related instruments, the instruments are not required for accident. mitigation. To maintain sump level between the high and low alarm setpoints, operators gravity drain the Reactor Building sump to the Auxiliary Building sump via remotely operated pneumatic valves. An interlock between LT-804 and valve WDL-V-535 closes the valve when sump level falls to 15" to prevent uncovering the drain line to the Auxiliary Building sump. An alarm setpoint at 13" l alerts operators 1

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l TSCR 209 of the failure of the automatic closure of WDL-V-535. With the exception of the functions associated with valve WDL-V-535, the instrumentation is limited ta providing level indication.

3) Deferring action to restore sump level instrumentation to an OPERABLE status during an outage period has both ALARA and industrial safety benefit. Work in the Reactor Building sump is typically performed during refueling outages an' is normally coordinated such that surveillances and repairs are done after a thorough cleaning of the sump, lhe cleaning reduces sump radiation levels and removes residues (slip hazards) from the sump floor and component surfaces.

4) The change will have no impact on safety since the existing hardware configuration, surveillance and operating procedures, and alarm setpoints remain unchanged. Further, limited continued operation without sump level instruments does not involve significant safety risk. The sump level instruments neither cause or mitigate an accident and are not relied on for any safety-significant automatic actions.

IV. No Sianificant Hazards Consideration _

Operation of the facility in accordance with the proposed amendment will have no adverse effect on nuclear sa r ety or safe plant operations.

Additionally, the TS will continue to provide assurance of the capability of the level instrumentation to furnish information to ~

indicate the breach of the primary coolant pressure boundary or provide information to indicate if plant safety systems functions are being accomplished without a narrow range instrument operable. GPUN has determined that this TS change request poses no significant hazards as defined by 10 CFR 50.92. Operation of the facility in accordance with the proposed amendment H 11 have no adverse effect on nuclear safety or safe plant operations r avaluated below:

1. Operation of the cility in accordance with the proposed amendment would not involve a significant increase in the prubability of occurrence or consequences of an accident previously evaluated.

Deletion of the wording beyond the point of term definition contained in the current definition of Heat Balance Calibration is an administrative change. The safety analysis requires that the heat balance error be not more than 2% and that the steady state difference between the Heat Balance and Nuclear Instrumentation be such that the Heat Balance would not be more than 2% greater than 3

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a ISCR 209 the Nucicar Instrumentation. Neither requirement is affected by this change.

Deletion of the action to shutdown the Reactot loss of a narrow range Containment Water level monitoring instr nt is appropriate because the accident analysis considerations wer, based on the original design and purpose rf the Reactor Butiding Sump. failure of the Cantainment Water Level monitoring instrument does not lead to an au ; dent and it is not required for accident mitigation.

2. Operation of the facility in accordance with the proposed amendment would not create the possibility of a new or dif forent kind of accident from any previously evaluated. The proposeo amendment does rot modify plant operation. It will continue to be operated in accordance with the limits of the existing accident analysis and margins of safety. The 2% maximum power level measurement error is unaffected by the change to the definition.

The Containment Water Level nonitering instrument has no interface

] with reactor systems.

3. Operation of the facility in accordance with the proposed amendment would not involv? a significant reduction in a margin of safety.

The proposed amenomont does not change any existing safety margins since the 2% maximum power level measurement error is unaffected oy the revision of the Heat Balance definition and there is no s'fety margin defined for the containment sump level instruments since they do not perform any accident-mitigating functions at THi-1.

V. Irnlementation It is requested that the amendment authorizing these changes become effective on issuance and shall be implemented within sixty days of receipt.

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