ML20085H434

Tech Spec Change Request 191 to License DPR-16,establishing Addl Requirements for Availability of LPRMs Associated W/ APRM Sys to Further Restrict Allowable Number of out-of-svc Lprm/Aprm Detectors to Respond to Hydraulic Oscillations

ML20085H434
Person / Time
Site:	Oyster Creek
Issue date:	10/09/1991
From:	J. J. Barton GENERAL PUBLIC UTILITIES CORP.
To:
Shared Package
ML20085H432	List: ML20085H428 ML20085H434 ML20085H440 ML20085H450
References
NUDOCS 9110280275
Download: ML20085H434 (5)

Text

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GPU NUCLEAR CORPORATION OYSTER CREEK NUCLEAR GENERATING STATION Facility Operating License No. DPR-16 i

Technical Specification Change Requent No. 191 Docket No. 50-219 Applicant submite, by this Technical Specification Change Request No. 191, to the Oyster Creek-Nuclear Generating Station Technical Specifications, a change to pagoa 3.1-1, 3.1-la (New), 3.1-6, 3.10-2, 3.10-3.

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f UNITED STATES OF AMERICA NUCLEAR REGULATORY COhMISSION In the Matter of )

) Docket No. 50-219 GPU Nuclear Corporation )

CE.RTIFICATE OF SERVICE This 10 to certify that a copy of Technical Specification Chango Request No.

191, for Oyster Creek Nuclear Generating Station Technical Specificatione, filed with the U.S. Nuclear Regulatory Cotmienion on October 9,1991 has thin day of October 9,1991 , boon served on the Mayor of Lacey Township, Ocean County, New Jetsey by deposit in the United States mail, addressed as follows:

The !!onorable Debra Madensky Mayor of Lacey Township 818 West Lacey Road Forked River, NJ 08731

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OYSTER CREEK NUCLEAR CENERATING STATION OPERATING LICENSE NO. DPR-16 DOCKET NO. 50-219 I. TECHNICAL SPECIFICATION CHANGE REQUEST h0. 191 CPUN requests that the following revisions be made to the Oyster Crsek Nuclear Generating Station Technical Specifications:

Replace pages: 3.1-1, 3.1-6, 3.10-2, 3.1.0-3 Add pages: 3.1-1(a)

II. REASON POR CHANGE This change is requested to ensure the ability of LPRM/APRM detectors to detect and suppress power oscillatione prior to exceeding any fuel design limits.

The changes to the current Technical Specifications are summarized below:

TS 3.1.B.3 will provide a more stringent requirement on the

-availability of Local Power Range Monitors (LPRM) associated with the

-Average Power Range Fonitoring (APRM) system by restricting the allowable number of out-of-service LPRM/APRM monitors on the "A" and "B" levels.

Ts 3.10.C.2 provides for a Minimum Operating Limit Critical Power Ratio (MCPR) to addreas core stability concerne.

III. EM3G'Y_ EVAtUATION The APRM neutron flux system. consists of the electronic equipment which averages the output signals from selected incore LPRMs, and

' develops an output signal related to percent of rated core thermal power. The APRM consists of eight (8) independent channels - two (2) channels per quadrant. Each APRM channel receives input from eight (8) LPRM detectors.

-The quadrant-based APRM system provides automatic reactor protection by generating a ficw-biased reactor trip signal based on the output of individual APRM channels. At least one APRM channel in each of the two(2) Reacter-) itection Systems (RPS) must have a high flux or inoperative trip corm tion to produce a full reactor scram.

Technical Specification Section 3.1.B.1 currently defines the minimum number of APRM channel inputa required to permit accurate average core power monitoring. Specifications 3.1.B.2 and 3.1.C.1 further define the distribution of the operable chambers to provide monitoring of local power changes that might be caused by a single rod withdrawal.

Section 3.10.C identifies requirements associated with the Minimum Critical Power Ratio (MCPR) during steady state power operations.

r, As a result of core wide oscillations at a US BWR, the NRC has questioned the adequacy of previous stability analyses and the ability of existing systems to detect and suppress large magnitude oscillations prior to violation ol~ fuel design ilmits. More recent analyses performed by GE have demonstrated that for large magnitude '

oscillations the potential does exist for violation of the safety limit MCPR. In response to this concern, GPUN has performed plant specific analyses to assess the capability of Oyster Creek's APRM system to respond to power oscillations.

APRM channel response is more sensitive to the availability of the A and B level detectors (bottom half of the core) than to C and D level detectors (top half of the core). APRM channel response is significantly improved if it can be assumed that'at least one channel (per RPS system) responding to regional oscillations has no more than one A level (or B level) detector oct of service. This Technical Specification Change Hequest (TSCR) adds a new section 3.1.B.3, which places additional and more restrictive operability requirements on the allowed number of out of service LPRM/APRM detectors on the A and a levels. This will ensure the availability of LPRM/APRM detectors in order ta provide a sufficient response to global as well as regional oscillations to prevent the violation of the MCPR safety limit.- This change maintains the existing plant configuratlon, does not add or delete any plant equipment, or change plant operating methods. It only changes the requirements declaring APRM channels-inoperable.

The TSCR also modifies Section 3.10.c by identifying a lower bound on the MCPR operating limit for each cycle as identified in the Core Operating Liinits Report (COLR). A lower bound limit is required to provide a sufficient MCPR operating margin to ensure the MCPR safety limit 10 not exceeded during global as well as regional power oscillations. This limit shs11 be greater than or equal to 1.47.

As a result of changes proposed herein, the ability to detect core wide and regional oscillations in the core are improved.

This TSCR does not. alter the existing plont configuration or chango plant operating methods. Therefore, as concluded in Section IV below, "No Significant Hazards Consideration," the proposed changes to the Technical Specification do not impact plant safety. In addition, the proposed changes do not violate plant Technical i Specifications or other Licensing requirements or regulations. The proposed changes enhance the ability to detect regional and global oscillations and do not. pose a safety concern.

IV. NO SIGNIFICANT HAZARDS CONSIDERATIQH GPUN has determined that this License Amendment request posee no L significant hazards as defined in 10 CFR 50.92 in-that operation of l Oyster Creek in accordance with the proposed amendment will nota l'

1. Involve a significant increase in the probability or consequences l of an accident nreviously evaluated since the activity is within current design basis for the affected transient. Also the existing plant configuration and method of operation are not changed by this TSCR.

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2. Croato the possibility of a now or d'fferent kind of accident frcm any accident previously evaluated since the activity previously described is of the same typo previouoly considorod (i.e., the potential for power oscillationa). Also, the existing plant configuration and method of operation are not changed by thin TSCR.

3. Involvo a significant reduction in a margin of safety since neither the fuel integrity limite nor the procedural requiromonto for established limiting conditions for operation are excoodod.

Also, the existing plant configuration and method of operation are not changed by this TSCR.

V. MEtif t1TATIOU It is requested that the amendment authorizing this TSCR be inouod by March 31, 1992 and be effectivo upon inauanco.

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