ML18033B517

Forwards Addl Info Re 900524 Tech Spec Change 287 on Reactor Pressure Instrument Channel.Schematic Diagrams Provided in Encl 2

ML18033B517
Person / Time
Site:	Browns Ferry
Issue date:	09/17/1990
From:	Wallace E TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
TVA-BFN-TS-111, NUDOCS 9009270078
Download: ML18033B517 (11)

Text

t ACCELERATED DISTRIBUTION DEMONSTRATION SYSTEM i

REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9009270078 DOC.DATE: 90/09/17 NOTARIZED: NO DOCKET FACIL:50-260 Browns Ferry Nuclear Power Station, Unit 2, Tennessee 05000260 AUTH. NAME AUTHOR AFFILIATION WALLACE,E.G. Tennessee Valley Authority RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk) R

SUBJECT:

Forwards addi info re 900524 Tech Spec Change 287 on reactor pressure instrument channel.

DISTRIBUTION CODE: AOOID COPIES RECEIVED:LTR ( ENCL I SIZE: D TITLE: OR Submittal: General Distribution S NOTES:1 Copy each to: S.Black,B.WILSON 05000260

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RECIPIENT COPIES RECIPIENT COPIES A ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL KREBS,M. 1 1 HEBDON,F 1 1 D ROSS,T. 2 2 D

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NOTE TO ALL "RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESK, ROOM Pl-37 (EXT. 20079) TO ELIMINATEYOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!

TOTAL NUMBER OF COPIES REQUIRED: LTTR 28 ENCL 26

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t TENNESSEE VALLEY AUTHORITY t

P. 0. Box 2000 Decatur, Alabama SEP i7 J99P TVA-BFN-TS-111 10 CFR 50.90 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555 Gentlemen:

In the Matter of Docket No. 50-260 Tennessee Valley Authority BROWNS FERRY NUCLEAR PLANT (BFN) TVA BFN TECHNICAL SPECIFICATION (TS) NO.

287 REACTOR PRESSURE INSTRUMENT CHANNEL UNIT 2 The subject request for TS change was submitted on May 24, 1990. Enclosure 1 provides additional information requested by the NRC staff during review of this request. Enclosure 2 provides schematic diagrams requested by the staff.

There are no commitments contained in this submittal.

If there are any questions, please telephone Patrick P. Carier (205) 729-3566.

Very truly yours, TE SSEE VALLEY AUTHORITY E. . a ace, Manager Nuclear Licensing and Regulatory Affairs Enclosures cc: See page 2 0

9009270078 900917 PDR ADGCK 05000260 PDC

@OS An Equal Opportunity Employer l(i

U.S. Nuclear Regulatory Commission

$ pp $ "(3%8 cc (Enclosure):

American Nuclear Insurers Attention: Librarian The Exchange, Suite 245 270 Farmington Avenue Farmington, Connecticut 06032 Ms. S. C. Black, Deputy Director Project Directorate II-4 U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852 Mr. Charles R. Christopher, Chairman Limestone County Commission P.O. Box 188 Athens, Alabama 35611 Dr. C. E. Fox State Health Officer State Department of Public Health State Office Building Montgomery, Alabama 36194 Mr. J. E. Jones General Electric Company 735 Broad Street Suite 1108 James Building Chattanooga, Tennessee 37402 NRC Resident Inspector Browns Ferry Nuclear Plant Route 12, Box 637 Athens, Alabama 35609-2000 Thierry M. Ross, Project Manager U. S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 208 Mr. B. A. Wilson, Project Chief U.S. Nuclear Regulatory Commission Region II 101 Marietta Street, NW, Suite 2900

'tlanta, Georgia 30323

ENCLOSURE 1 NRC REQUEST FOR ADDITIONAL INFORMATION TS 287 dd tiona o t o e ueste (1) Pressure switches 2-PS-68-93 6 94 are not identified in TS Table 3.2.A "Primary Containment and Reactor Building Isolation Instrumentation".

They are 1'isted under Function as: "Instrument Channel Reactor High Pressure." TVA proposes to identify pressure switches 2-PS-68-93 k 94 in TS Table 4.2.A, but this correction is not proposed for TS Table 3.2.A.

TVA should correct TS Table 3.2.A to identify press@re switches 2-PS-68-93 6 94.

TVA Res onse The existing Technical Specification (TS) Table 3.2.A lists the function of the involved pressure switches but does not provide the instrument numbers.

The proposed TS change added Table 4.2.A but did not propose a similar change to Table 3.2.A. The instrument numbers are proposed to be added to Table 3.2.A in TS change request 282 which was submitted to the NRC on August 6, 1990.

dditio a Infor ation Re uested (2) The proposed functional test interval is once per 3 months, and the proposed calibration test interval is once per 18 months. TVA's only justification for proposing to increase the calibration frequency is as follows: "The calibration frequencies for the new pressure switches are based on the manufacturer's recommendation and are supported by

'alculations." The licensee offered no justification for the increase time between functional tests. In general TVA needs to provide a more detailed justification for their proposal to increase the TS surveillance requirements. .In particular, TVA should quantify or qualify any impact these changes 'may have on safety.

TV Res onse The increased functional test surveillance interval is justified by the improved reliability obtained by. the use of Class lE Static-0-Ring (SOR) pressure switches. The=previously installed pressure switches were not class lE and have been subject to 'problems with accuracy and drift. As a result of these problems, the switches have been replaced with more reliable and accurate switches.

Although not required, the switches were purchased to SOR's class lE qualification for increased reliability. The switch type was subjected to a series of tests including mechanical aging by cycling the unit 33,000 times at the upper adjustable limit and exposing the unit to the LOCA- environment to determine the affect on the performance of the switch. The switch successfully demonstrated the capability to withstand the test conditions.

Enclosure 1 Page 2 of 3 The application of the switches is to isolate the RHR shutdown cooling suction valves when the reactor vessel pressure is above the shutdown cooling range.

Tn normal operation the switches will be sensing reactor operating pressure inhibiting the manual opening of the suction valves until the pressure falls below,100 psig or closing the valves when the pressure rises above 100 psig.

The anticipated duty cycle would be the quarterly functional testing and number of shutdowns. A number of 10 cycles per year is considered to be conservative. The pressure switches are not required to operate during any 10 CFR 50.49 event.

TVA, by calculation, has established setpoint values based on a 22 1/2 month calibration interval. Drift due to the pressurization of the switches above the upper adjustable limit is included in the calculation.

The improved reliability and proper application of the new pressure switches provides substantial assurance that the switches will properly perform their function with an increase in the functional testing interval from monthly to quarterly. Thus the increase in the functional surveillance interval is not expected to have an adverse impact on safety; The proposed increase in the calibration surveillance interval is supported by the accuracy and drift characteristics of the class lE pressure switches. A setpoint and scaling calculation has been performed which demonstrates the acceptability of the increased calibration surveillance interval. Using vendor supplied instrument accuracy and drift information,'he calculation determined the affect of a '22-1/2 month interval, between calibrations.

(Twenty-two and a half months is the maximum interval between surveillance with an 18-month interval.) The results of the calculation demonstrated that the proposed increase in the calibration interval does not adversel'y affect the function of the instruments. A copy of the calculation has been. made available for NRC review at the TVA office in Rockville, Maryland.

Additional I formation Re uest d (3) The staff requests TVA to provide schematic diagrams of valves 2-FCV-74-47, 2-FCV-74-48, 2-FCV-73-53, and 2-FCV-74-67.

Schematic diagrams which provide the logic changes are attached as Enclosure 2.

Additional Information Re uested (4) The staff is unclear about the safety function of the number 1 switch of pressure switches 2-PS-68-93 6c 94. In Enclosure 3 of TVA's TS amendment

'application, "Reasons and Justification for Changes" the following is stated: "The only safety function performed by switches 2-PS-68-93 and 2-PS-68-94 is the high pressure isolation signal . . . . This function is accomplished by SWj2." On page 2 the following is stated: "The only

Enclosure 1 Page 3 of 3 remaining safety function performed by switches 2-PS-68-93 and 2-PS-68-94 is the high pressure isolation signal . . . ." The licensee is asked to clarify these statements (i.e., "the only safety function" versus "the only remaining safety function.")

ea Switch $51 of 2-PS-68-93 and 2-PS-68-94 did not perform a safety function. The only safety function performed by these switches was the high pressure isolation signal to close the RHR inboard/outboard isolation valves 2-FCV-74-47 and 2-FCV-74-48 which was provided by Switch g2. This function is still preserved by the proposed change. The specific wording differences between the description of Reaso for-C an es and Justi ication for the

~Chan es did not mean to imply a safety function is being deleted.

The function of Switch $11 of the switches was to provide a non-safety permissive signal for isolation of isolation valves 2-FCV-74-53 and 2-FCV-74-67. This permissive signal is redundant to the permissive signal provided by limit switches on 2-FCV-74-47 and 2-FCV-74-48 when these valves are open. Valves 2-FCV-74-47 6 2-FCV-74-48 cannot be opened unless reactor pressure is below 100 psig. Thus the permissive provided by switch iIl is unnecessary.

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0 ENCLOSURE 2 NRC REQUEST FOR ADDITIONAL INFORMATION TS 287 SCHEMATIC DRAWINGS OF LOGIC CHANGES

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