ML20151Q552

Submits Rev to FSAR Section 14.2.12.3,deleting Initial Startup Test 26, Dynamic Rod Drop Test. Justification for Deleting Test Based on WCAP-10297 Which Has Demonstrated Listed Items

ML20151Q552
Person / Time
Site:	South Texas
Issue date:	07/28/1988
From:	Mcburnett M HOUSTON LIGHTING & POWER CO.
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
Shared Package
ML20151Q556	List: ML20151Q552 ML20151Q561 ST-HL-AE-2695, Informs That More Definitive Test of Negative Flux Rate Trip Performed on Both Four & Three Loop Plants W/Rod Worths Significantly Less than Max Worth Noted in WCAP-10298, Resulting in Indication of No Reactor Trip
References
ST-HL-AE-2695, NUDOCS 8808110207
Download: ML20151Q552 (12)

Text

The Light company " "'

liouston Lighting & Power _ ._

July 28, 1988 ST-HL-AE-2695 File No.: G20.01 10CFR50.59 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 South Texas Project Electric Generating Station Unit 1 Docket No. STN 50-498 Revision to FSAR Section 14.2.12.3:

Initial Startup Test #26, "Dynamic Rod Drop Test"

References:

1. ST-WN-YB-3305, "Deletion of Dynamic Rod Drop Test During Plant Startup", April 7, 1987.

2. WCAP-10297-P-A, "Dropped Rod Methodology for Negative Flux Rate Trip Plants", June, 1983.

3. Letter f rom Cell 0. Thomas (NRC) to E. P. Rahe, Jr.

(Westinghouse), March 31, 1983.

Pursuant to license condition 2.C(4) of Facility Operating License No.

NPF-76, Houston Lighting & Power Company (HL&P) submits the attached description of a change in the South Texas Project Electric Generating Station (STPEGS) Initial Test Program. The description addresses the deletion of Test

1. 26, "Dynamic Rod Drop Test".

Test description #26, although not required by Regulatory Guide 1.68, was l included in Final Safety Analysis Report (FSAR) Chapter 14.2 to address i verification of the capability of the negative rate trip circuitry to detect l the simultaneous insertion of two Rod Cluster Control Assemblies (RCCA) and to l trip the reactor trip breakers. Westinghouse has recommended (Reference 1) deletion of the Dynamic Rod Drop Test (performed at 50% power) to all plants of current Westinghouse design which have not performed this test as part of the initial startup test program. Justification for deleting the test is ,

based on WCAP-10297 (Reference 2) which has demonstrated that: I

a. The STPEGS Technical Specification (Table 3.3.1) negative rate trip setpoint of 5% Rated Thermal Power (RTP) in 2 seconds will result in a reactor trip for dropped rod worth above 400 pcm (.004 A k/k). j U

P I ru,88.162.05 A Subsidiary of Ilouston Industries Incorporated }

Ilouston 1.ighting & Power Company ST-HL-AE-2695 File No.: G20.01 10CFR50.59 Page 2

b. Dropped rad worth less than 400 pcm will not cause local flux peaking which could cause an unconservative local departure from nucleate boilie? ratio to exist.

NRC approval of WCAP-10297 was provided in Reference 3.

Therefore, since the negative rate trip circuitry has been adequately demonstrated to function as required, performance of the negative flux rate trip at STPEGS is unnecessary.

It is important to note that the total reactivity inserted as a result of the drop of the two rods is essentially independent of core height.

Therefore, the fact that STPEGS uses 14 foot fuel does not alter the results of the WCAP as it applies to STPEGS. In addition, specific analysis for conditions where a negative rate trip is not expected (i.e., negative reactivity insertion less than 400 pcm) is presented in FSAR section

'5.4.3.2.2.

It is our understanding that at least three recent Westinghouse plants have not performed this test, specifically Vogtle, Millstone 3, and Catawba 1.

The attached evaluation pursuant to 10CFR50.59 confirms that this change does not constitute an unreviewed safety question. The revised FSAR page has been included to illustrate the changes.

If there are any questions on this matter as it relates to the 10CFR50.59 evaluation or other issues, please contact me at (512) 972-8530.

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M. A. McBurnett Manager-Operations Support Licensing l

MAM/SMH/nl Attachments: 1) Unreviewed Safety Question Evaluation 88-065

2) Revised FSAR page 14.2-146

3) ST-WN-YB-3305, April 7, 1987, "Deletion of Dynamic Rod Drop Test During Plant Startup" NL 88.162.05

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e flouston 1.ighting & Power Company ST-HL-AE-2695 File No.:G20.01 Page 3 LCt Regional Administrator, Region IV Rufus S. Scott Nuclear Regulatory Commission- Associated General Counsel 611 Ryan Plaza Drive, Suite 1000 Houston Lighting & Power Company Arlington, TX 76011 P. O. Box 1700 Houston, TX 77001 George Dick U. S. Nuclear Regulatory Commission INPO Washington, DC 20555 Records Center 1100 circle 75 Parkway Jack E. Bess Atlanta, Ga. 30339-3064 Resident Inspector / Operations e/o U. S. Nuclear Reculatory Commission Dr. Joseph M. Hendrie P. O. Box 910 50 Bellport Lane Bay City, TX 77414 Bellport, NY 11713 Don L. Garrison Resident Inspector / Construction c/o U. S. Nuclear Regulatory Commission P. O. Box 910 Bay City, TX 77414 J. R. Newman, Esquire Newman & Holtzinger, P.C.

1615 L Street, N.W.

Washington, DC 20036 R. L. Range /R. P. Verret Central Power & Light Company P. O. Box 2121 Corpus Christi, TX 78403 R. John Miner (2 copies)

Chief Operating Officer City of Austin Electric Utility 721 Barton Springs Road Austin, TX 78704 R. J. Costello/M. T. Hardt

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City Public Service Board P. O. Box 1771 San Antonio, TX 78296 Revised 06/07/88 NL.DIST

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ATTACHMENT 1

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ST-HL-AE-2695 File No.: G20.01 10CFR50.59 Unreviewed Safety Question Evaluation #88-065 Subj ect: Initial Startup Test #26, "Dynamic Rod Drop Test" .

Description:

FSAR Section 14.2.12.3 Test Description #26,"Dynamic Rod Drop Test", is being deleted from the STPEGS initial startup test program. Regulatory Guide 1.68 does not require this test and its deletion has been recommended by Westinghouse with technical justification for deleting the test contained in WCAP-10297.

WCAP-10297, which is applicable to STPEGS, has demonstrated thats

a. The STPEGS Technical Specification (Table 3.3.1) negative rate trip setpoint of 5% RTP in 2 seconds will result in a reactor trip for dropped rod worth above 400 pcm.

b. Dropped rod worth less than 400 pcm will not cause local flux i peaking which could cause an unconservative local Departure

! from Nucleate Boiling Ratio (DNBR) to exist.

WCAP-10297 has been approved by the NRC.

Safety Evaluations l 1) Does the subject of this evaluation increase the probability of occurrence or the consequences of an accident or malfunction of equipment important to safety previously I

evaluated in the safety analysis report?

I l The probability of occurrence or the consequence of an accident or malfunction of equipment important to safety is not changed as a result of the deletion of the negative rate trip test. The purpose of the negative rate trip test was l to ensure the operability of the negative rate trip circuitry and to review plant response and control system l behavior. The purpose of the procedure is met without conducting the test due to the following:

l a. The electronic portion of the negative rate trip l circuitry is verified by surveillance procedures.

NL.88.162.05

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. ST.HL AE. A0'96 Ilouston 1.ighting & Power Comp.my PArJ J OE2A -

ST-HL-AE-2695 File No.: G20.01 10CFR50.59

'Unreviewed Safety Question Evaluation #88-065 (Cont'd.)

b. WCAP-10297 has demonstrated that the STPEGS Technical Specification negative rate trip setpoint will ensure that a reactor trip will result for dropped rods under conditions where the total worth of the rods could cause an unconservative local DNBR to exist.

c. The plant responce and control system behavior following a 50% loss of load will be demonstrated at 75% and 100%

power levels prior to the plant trip from 100% power.

The plant response and control system behavior following a plant trip below 50% power has been adequately demonstrated during the course of power ascension testing completed to date.

2) Does the subject of this evaluation create the possibility for an accident or malfunction of a different type than any evaluated previously in the safety analysis report?

The plant will not be subjected to the negative flux rate trip which is a consequence of this test. The plant will instead continue operating at 50% power. Therefore, there is no possibility of an accident or malfunction of a different type than previously calculated in the safety analysis report.

3) Does the subject of this evaluation reduce the margin of safety as defined in the basis for any technical specification?

The purpose of this test is to validate the Technical Specification Setpoint that forms the basis for the Neutron Flux, High Negative Rate Trip. Deletion of this test does not reduce the basis for this setpoint since it is adequately verified in WCAP-10297.

Based upon the above, there is no unreviewed safety question.

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d. Method

1) Evacuation of the main control room is simulated by dispatching )

personnel (not to exceed a minimum shift crew).to the safe

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shutdown control stations while additional' operators occupy the 53 10 control room to observe plant behavior. Q423.

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2) The reactor is tripped at the' reactor trip switchgear.

3) The plant is maintained in the hot standby condition by manipu-lation of safe shutdown controls and observation of safe shutdown indications for at least 30 minutes. During this 53 demonstration, only that equipment for which credit would be taken for performing an actual safe shutdown will be used.

26. Dynamic Rod Drop Test (DELDh

a. Test Objective - This test will verify the operation of the negative rata trip circuitry in detecting the simultaneous insertion of two CAs.

b. Acce ance Criteria

1) The reactor trips as a result of the negative rate trip.

2) SG and ressurizer safety valves do not lift.

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3) SI is not 1 itiated.

c. Prerequisites

1) All poh r'-rangc nu i.cn innrumenterion thannels are operable.

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2) The reactor is at the teady-state power level of approximately Q423~

50 percent with the con olling bank near the full power inser- 32 tion limit.

3) Pertinent parameters to be me ured.are connected to recorders. 10 Q423.

d. Method 22(4.t)

1) Two of the least reactive rods from e group most difficult to detect by excore detectors due to low rth and core location are simultaneously dropped by removing vo tage to both the moveable and stationary gripper coils of th designated rods. .

2) Following the transient, recordad data is evalu ted for system and instrumentation response.

I l 27. Static RCCA Drop and RCCA Belov-Bank Position Measurements Test

a. Test Objective - Tnis test will obtain the differential and integral worth of the most reactive below bank RCCA, will de=enstrate the i

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14.2-146 Amendment 56

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1,.,' , ST-WN-YB-3305 UKTTACHMENT 3

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Westinghouse Power Systems NEs$$$n*

Electric Corporation

, 333 PMsktgh Penns)ivania 15230-0355 April 7, 1987 S.0. No: TGX/THX-4705 TGX/THX-12 Mr. A. Matiuk, Project Engineering Hanager Bechtel Energy Corporation 5400 Westheimer Court P.O. Box 2166 Houston, Texas 77252-2166 SOUTH TEXAS PROJECT UNITS NUMBERS 1 & 2 CONTRACT NUMBERS 35-1197-4000 AND 35-1197-8000 DLLETION OF DYNAMIC ROD DROP TEST DURING PLANT START-UP

Dear Mr..Matiuk:

This letter is in response to a teleton from HL&P (M. Friedlander) to Westing-house (J. L. Duryea) on March 17,'1987.

Attached for your information is Enclosure 1 for your use in support of the deletion of the Dynamic Rod Drop Test at the 50 percent reactor power level.

Please note that Regulatory Guide 1.68 does not require such a test, thus no exception is necessary to delete it. Enclosure 2 provides some additional background informatio.l. Enclos".:re 3 provides the FSAR pages marked up to show the changes to reflect this deletion.

If you have any questions, please feel free to contact us.

Very truly yours, HESTINGHOUSE ELECTRIC CORPORATION South Tex Project fe}

M0per/ dab /4185F Attachment 4185F:51

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N. C. Horning (BEC) ll, lA

• .H. Kinsey.(HL&P site) IL RMS (BEC) IL, lA E. H. Dotson (HL&P) 2L, 2A B. H. Heery (B Houston Office)- IL, lA G. Glasbergen-(d Sc. Texas Site) . 2L, 2A R. Shomo (H So. Texas Site) IL, lA M. Friedlander (HL&P) IL, lA J

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Westinghouse, to C. H. Berlinger, NRC.

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