ML20246P181

Summary of 890506 Meeting W/Utils & Westinghouse Re Licensee Decision to Remove Remainder of Excessive Cooldown Protection Circuitry & Amend to Tech Specs.List of Meeting Attendees & Licensee Meeting Handout Encl

ML20246P181
Person / Time
Site:	South Texas
Issue date:	05/09/1989
From:	Dick G Office of Nuclear Reactor Regulation
To:	Office of Nuclear Reactor Regulation
References
NUDOCS 8905220110
Download: ML20246P181 (35)

Text

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(/ p Rt;g k, UNITED $TATEs [

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k...../ May 9, 1989 Docket No. 50-498 LICENSEE: Houston Lighting & Power Company FACILITY: South Texas Project, Unit 1

SUBJECT:

REMOVAL OF REMAINDER OF THE EXCESSIVE C00LDOWN

• PROTECTION CIRCUITRY The subject meeting was held on May 6, 1988 to discuss the licensee's decision to remove'the remainder of the excessive cooldown protection circuitry for the

~

plant and amend the plant Technical Specifications accordingly. An initial submittal, containing background information was submitted on April 18, 1988.

Enclosure 1 contains the list of meeting attendees. A copy of the licensee mceting handout is included as Enclosure 2.

Excessive cooldown protection was in the original design of South Texas Project to prevent the reactor from returning critical subsequent to a steam system piping failure or inadvertent opening of steam generator relief or safety velve, or excessive main feedwater addition. South Texas Project subsequently adopted NRC approved licensing criterion which permits return to criticality following the above mention events. Two portions of the original excessive cooldown protection, emergency boration system and rr.ain steam isolation on any safety injection, were deleted prior to issuance of the cperating license for South Texas Prcject, Unit 1.

During the startup of South Texas, Unit 1 (STP-1) the licensee determined that the Low-Low Compensated T-Cold Excessive Cooldown Protection circuitry would initiate a safety injection actuation if charging flow was maintained after the Reactor Coolant Pumps tripped. This condition was unique to the STP design as a result of the inclusion of excessive cooldown protection circuitry. This condition was considered to be undesirable since it resulted in unwarranted cycling of safeguards equipment and ccrrplicated the response to less significant events. The licensee concluded that anytime the Peactor Coolant Pumps are stopped while charging flow is maintained, a safety injection actuation will occur due to excessive cooldown protection.

During the meeting, the licensee provided the basis for its request to remove the circuitry and expected result of its removal from both a safety and an operational viewpoint.

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-2 A request for license amendment was subsequently submitted and reviewed by the' staff. The staff approved the license ('s request in Amendment No. I to the STP-1 license on May 24, 1988, OricinciSign::d By Ge6rge F. Dick,Jr.

George F. Dick, Project Manager Project Directorate - IV Division of Reactor Projects - III, IV, V and Special Projects.

Office of Nuclear Reactor Regulation

Enclosures:

As stated '

.cc w/ enclosures:

See next page DISTRIBUTION Docket File NRC PDR Local PDR J. Sniezek PD4 Reading J. Calvo F. Hebdon G. Dick OGC-Rockville E. Jordan B. Grimes

.H. Li P. Kandambi H. Balukjian J. Mauck

-ACRS (10)

T. Martin (RegionIV)

PD4 Plant File DOCUMENT NAME: MTG

SUMMARY

STP PD4/(

/PM PD4/D/

PNeana

" # GDick:bj JCalvo 05/9/89 05/c$789 05/9 /89

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A request.for license amendment was subsequently submitted and reviewed by the staff. The staff approved the licensee's request in Amendment No. I to the STP-1 license on May 24, 1988.

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4AdA George Dick,ProfactManager Project' Directorate - IV Division of Reactor Projects - III, IV, V and Special Projects Office of Nuclear. Reactor Regulation

Enclosures:

As stated cc w/ enclosures:

See next page 1

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M'r. J. H. ' Goltiberg . South Texas Project l{ Houston' Lighting.and Power Company-cc:'

r Brian Berwick, Esq. Resident Inspector / South Texas L ' Assistant Attorney General .,

Project Environment 1> Protection Division c/o U.S. -Nuclear Regulatory Comission l

,P. O. Box 12548' P. O. Box 910

. Capitol Station Bay City, Texas 77414-L Austin, Texas 78711 Ms. Iris J. Jones Mr. J. T..Westermeier Acting City Attorney City of Austin

, General ~ Manager, South Texas Project Houston Lighting and Power Company' P. O. Box 1088

'P. 0.' Box 289 . Austin, Texas .78767 Houston, Texas 77483 Ms. Pat Coy. . . ,

Mr. R. J.~ Miner. Citizens Concerned About Nuclearl Chief Operating Officer Power City of Austin Electric Utility. 10 Singleton 721 Barton Springs Road Eureka Springs, Arkansas 72632 Austin, Texas 78704 ..

Mr. M. A. McBurnett Mr. R. J. Costello Manager, Operations Support Licensing Mr. M. T. Hardt Houston Lighting and Power Company City-Public Service Board P. O. Box 289 P. O. Box 1771 Wadsworth, Texas 77483 San Antonio, Texas 78296 Mr. E. T. Molnar Jack R. Newman, Esq. Mr. L. W. Hurst Newman & Holtzinger, P. C. Bechtel Corporation 1615 L Street, NW P. O. Box 2166

' Washington, D.C. 20036 Houston, Texas 77252-2166 Melbert Schwartz, Jr., Esq. '

Mr. R. P. Verret Baker.& Botts Mr. R. L. Range One Shell Plaza Central Power and Light Company

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Houston Texas 77002 P. O. Box 2121 Corpus Christi, Texas 78403 Mrs. Peggy Buchorn Executive Director Doub, Muntzing and Glasgow Citizens for Equitable Utilities, Inc. Attorneys-at Law

~~ Route 1. Box 1684 Suite 400 Brazoria, Texas 77422 808 Seventeenth Street, N.W.

Washington, D.C. 20006 Mr. S. L. Rosen

' General Manager, Operations Support Houston Lighting and Power Company P. 0. Box 289 Wadsworth, Texas- 77483

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L, Nr. J.' H. Goldberg South Texas Project Houston Lighting & Power Company cc:

' Regional Administrator, Region IV Bureau of Radiation Control U.S. Nuclear Regulatory Commission State of Texas Office of Executive Director 1101 West 49th Street for Operations Austin, Texas 78756

! 611 Pyan Plaza Drive, Suite 1000 i- Arlington, Texas 76011 Office of the Gobernor ATTN: Ms. Darla Parker Mr. Lanny' Sinkin, Office of Intergovernmental Relations Counsel for Intervenor Post Office Box 13561 Citizens Concerned about Nuclear Austin, Texas 78711

. Power, Inc.

Christic Institute Judge, Matagorda County 1324 North Capitol Street Matagorda County Courthouse

' Washington, D.C. 20002 1700 Seventh Street Bay City, Texas 77414 Licensing Representative Houston Lighting and Power Company Suite 610 Three Metro Center Bethesda, Maryland 20814 Rufus S. Scott Associate General Counsel Houston Lighting & Power Company P. O. Box 1700 Houston, Texas 77001 .

INP0 Records Center 1100 Circle 75 Parkway Atlanta, Georgia 30339-3064 Joseph M. Hendrie 50 Be11 port Lane Be11 port, New York 11713

-Gerald E. Vaughn, Vice President Nuclear Operations Houston Lighting & Power Company P. 0.. Box 289 Wadsworth, Texas 77483 R. W. Chewning, Chairman Nuclear Safety Review Board Houston Lighting & Power Company P. O. Box 289 Wadsworth, Texas 77483

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, Enclosure 1 South Texas Project, Unit 1 Excessive Cooldown Protection System May 6, 1988 l.

Name Organization George Dick Hulbert-Li NRC Prasad Kadambi NRC Harry Balukjian NRC Chu yu Liang NRC Jerry Mauck NRC Mark Wisenburg HL&P Leonard Casella HL&P M. Friedlander HL&P R. Munter HL&P Mark McBurnett HL&P John Irons Westinghouse John Reck Westinghouse Glenn Long Westinghouse Bruce Lorenz Westinghouse Bryan McLauchlin CPL l

____.._.______.__________.___________U

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Enclosure 2

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EXCESSIVE C00LDOWN PROTECTION SYSTEM l

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MAY 6, 1988 l

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EAYE E A P R N RVRTM D F O O OOA U N O N CFO MTG C E STO I

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I TT YI OIT VE I F G VG Y CI USL P AT S TG O N N N R AA I DI TRW A RNTN TS I

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LICENSING HISTORY

• . Excessive Cooldown System Originally Incorporated Following Features Emergency Boration System o Additionh1methodforinjectingboratedwaterintoRCS-o NRC Approved Relaxed' Licensing Criteria Adopted o Removed to South Texas Project in 1983

- Main Steamline Isolation Signal Generated on any Safety Injection Signal o- Originally designed to. expedite secondary high energy line rupture blowdown isolation o Removed on South Texas Project in 1986 to simplify. recovery from small LOCA Transients Excessive Cooldown Protection System 1 o Safety injection actuation on Tcold signal o Feedwater isolation and turbine trip on

+ T cold

+ Feedwater Flow l

and RCS Flow or T ,yg l.

. WHAT IS THE EXCESSIVE COOLDOWN PROTECTION SYSTEM-

• Safety Injection Actuation and Steamline' Isolation 2/3 Lo-Lo Compensated Tcold in'Anv Loop Below j P-15 -

3 Feedwater Isolation and Turbine Trip 2/3 Low Compensated Tcold in Any Loop Below P-15 2/3.High Feedwater Flow in Any Loop Below P-15 In Coincidence With 2/3 Low RCS Flow-nr In 2/4 Loops Low T avg P-15 Interlock i

- 2/4 Power Range Signals Below Setpoint 2I P-4 1

0064C/ GEL 4/0421BB

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WHAT IS THE EXCESSIVE C00LDOWN PROTECTION SYSTEM (CONTINUED)

CURRENT,SETPOINTS

+ LO-LO COMPENSATED T COLD < 532 ' F

- 12 SECOND LEAD TIME CONSTANT

- .3 SECOND LAG TIME CONSTANT F

+ L0 COMPENSATED T COLD < 538

- 12 SECOND LEAD TIME CONSTANT 3 SECOND LAG TIME CONSTANT

+ P-15 < 10% RATED THERMAL POWER

+ HIGH FEEDWATER FLOW > 30% FLOW

+ LOW RCS FLOW < 91.8% OF LOOP DESIGN FLOW

+ < 574 F LOW T,,jg

+ VARIABLE TIME DELAY : 0 TO 5 SECONDS i

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,,3, ALTERNATIVES CONSIDERED Lowering Lo-Lo Tcold Setpoint Plant Transients Yielded Cold teg Temperature Be, low Bottom of Range (510 to 630. degrees F)

Would Not Preclude Referenced Plant Transients

• Alternate Lead / Lag Time Constants Plant Transients Yielded Cold Leg Temperature Below Bottom of Range (510 to 630 degrees F)

Would Not Preclude Referenced Plant-Transients Add Time Delay to Actuation Logic Plant Transients Yielded Cold Leg Temperature Below Bottom of Range for Long Periods of Time Would Not Preclude Referenced Plant Transients

• Removal of Excessive Cooldown Protection System l

1 1 Actuations l-0064C/ GEL:8/042188

g. - ..

[ l '.,

( :f

, .. .j

. 4 WHY WAS EXCESSIVE'COOLDOWN PROTECTION l-- SYSTEM IN ORIGINAL DESIGN

[

• To Prevent the Core from Returning Critical Subsequent to the Following ANS. Condition II Events Steamline Rupture Excessive Main Feedwater Addition DD57B/ GEL:6/D42188

.; $'l '

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'. . IMPACT OF REMOVAL OF EXCESSIVE C00LDOWN PROTECTION SYSTEM South Texas . Project has Adopted NRC Approved Relaxed Licensing. Criterion Which Permits Return

' ~

to Critical'ity Following ANS Condition II Steamline Rupture and Excessive Feedwater Transients FSAR Chapter 6/15 Accident Analysis Do Not Take Credit for Excessive Cooldown Protective' Function for Mitigation-Documentation Updates Hardware Modifications l

Procedure Revisions Operator Retraining I'

l 0064C/ GEL:10/042168

_ _ . . .. .-- .___-_-.-__.____-_________-_ _-__-_-__-__ _ _ _ _ _ _ .- ~

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I ADVANTAGES OF REMOVAL I-Minimizes Inadvertent Safety Injection Actuations

1

~ '

Less cycling of ESF equipme'nt Normal response to expected transients Less Surveillance Testing L

• Simplifies Plant Cooldown Procedures Res'alts in South Texas Project Protection System Functionally Equivalent to RESAR-3S Protection System (NUREG-0104) i i

l

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I i

L 0064C/ GEL:9/042188

.. ..." ,- - l

-e 6

, AREAS INVESTIGATED Licensing

+ FSAR Chapter 5 Design Transients

+ FSAR. Chapter 7 I&C Requirements

+ FSAR Chapter 6/15 Safety-Analyses

+ FSAR Chapter 16, Technical Specifications-

- Statistical Setpoint Study

"+ FSAR Cha'pter' 14 'Startup Testing-

+ Fire Hazards Analysis

+' Long Term Cooling Study

+ NRC Questions / Utility Responses

+ Safety Evaluation Report (NUREG-0781) Through Supplement 5 Procedures / Testing

+ Startup Test Procedures

+ Surveillance Procedures

+ E0P/A0P Procedures Human Factors / Training

+ Control Board Displays

+ Plant Computer Inputs

+ Training Manuals l

'DD64C/ GEL:12/042188

• +

4 ;e

..- LICENSING DOCUMENTATION' MODIFICATIONS lp

• FSAR' Table 1.3.2 Section 3.9.1.1.-7.10 Section 5.2.2.11.3 Section 6.2.1.4 -

Section 7.1.2.1.8 Table 7.1-2' Figure 7.2.2 Section 7.3.1.1.3 Section 7.3.1.1.5.2 ,

Section 7.3.1.1.5.3 Section 7.3.1.1.5.6.1 Section 7.3.1.1.5.6.2 Section 7.3.1.1.5.6.3 Section 7.3.1.2.1 Section 7.3.1.2.2.5.4.2 Section 7.3.1.2.2.6 Table 7.3-2 Table 7.3-3 Table 7.3-4 Section 10.3.2.5

~

Table 15.0-6 Figure 15.0-9 Section 15.1.4.1 Section 15.1.5.1 0064C/6EL:2/042188

p .:

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^'

.. , LICENSING DOCUMENTATION MODIFICATIONS l-l (CONTINUED)

LTechnical Specifications (NUREG-1305)

Table 3.3-3 Table 3.3-4 Table 3.3-5 Table 4.3.2 -

~

Section 3/4.3.1/.2 NRC Questions 212.164 (for information only) 211.85 (for information only) 440.01N 211.52 440.80N 211.32 Safety Evaluation Report (NUREG-0781)

Section 7.3.1 Section 7.3.1.4 Section 15.1.4 Section 15.1.5.1 Section 15.6.3 Safety Evaluation Report (NUREG-0781 Supplement 3)

Section 7.3.2.2 l

0064C/ GEL:3/042188

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+

pp . , _

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SUMMARY

l' '

o EXCESSIVE C00LDOWN PROTECTION SYSTEM RESULTS IN UNNECESSARY E'SF-

'o -, ACTUATIONS o NO CREDIT IS TAKEN FOR MITIGATION OF TRANSIENTS BY EXCESSIVE'COOLDOWN.

PROTECTION IN THE STPEGS LICENSING BASIS o DELETION OF EXCESSIVE C00LDOWN PROTECTION RESULTS'IN A PROTECTION-SYSTEM FUNCTIONALLY EQUIVALENT TO RESAR 3S PLANTS

o. DEFER LOOP TEST AND SHUTDOWN OUTSIDE THE CONTROL ROOM TEST UNTIL THE 1 MODIFICATION IS APPROVED'BY NRC AND IMPLEMENTED o ALL START-UP TESTING IS SCHEDULED FOR COMPLETION BY MID JUNE 1988 o SUBMITTAL OF TECH SPEC CHANGE REQUEST IS SCHEDULED FOR MAY 13, 1988

^

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