ML20046C333

Forwards Response to GL 93-04,summarizing Current Compensatory Actions Taken by Util in Response to Salem Rod Control Sys Failure Event

ML20046C333
Person / Time
Site:	South Texas
Issue date:	08/05/1993
From:	Cloninger T HOUSTON LIGHTING & POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GL-93-04, GL-93-4, ST-HL-AE-4533, NUDOCS 9308100154
Download: ML20046C333 (7)

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The Light i c o mp a nyS uth Texas Project Ucctric Generating P. O.Station Box 289 Wadsworth, Texas 77483 Houston Lighting & Power August 5,1993 ST-HL-AE-4533 File No.:G03.08 10.CFR50.54(f) 1 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555 South Texas Project Units 1 and 2 Docket NO. STN 50-498, STN 50-499 TRANSMITTAL OF RESPONSE TO GENERIC LETTER 93-04 In accordance with 10 CFR 50.54 (f) Houston Lighting & Power hereby submits its 45 day response to the Generic Letter as it applies to South Texas Project Units 1 and 2. This response summarizes the current compensatory actions taken by Houston Lighting & Power in response to the Salem rod control system failure event. This ,

response also provides a summary of the results of the generic safety analysis program conducted by the Westinghouse owners Group (WOG) and its applicability to South Texas Project Units 1 and 2.

Houston Lighting & Power considers this action to be complete with respect to the 45 day required response to GNL 93-04 (as amended by July 26 NRC letter to Mr. Roger Newton of the WOG).

At the present time South Texas Project Units 1 and 2 are in extended outages. HL&P currently does not plan to take either Unit 1 or Unit 2 to modes 1 or 2 prior to the date of the required 90 day response (September 20, 1993).  :

Should you have any questions on this matter, please co bt Mr. S. M. Head at (512) 972-7136 or me at (512) 972-8133 /,

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Attachment:

Affidavit t South Texas Project Generic Letter 93-04 Response GLB\93-217.001 g_

Project Manager on Behalf of the Participants in the South Texas Project ~y I

9308100154 930805 U l-PDR ADOCK 05000498 M S PDR k

Ho uton lighting & Power Company

~ Si.un Texas Project Electric Generating Station ST-HL-AE-4533 File No. G03.08 l 10CFR50.54(f)

Page 2 c: .

Regional Administrator, Regien IV Rufus S. Scott Nuclear Regulatory Commission Associate General Counsel .i 611 Ryan Plaza Drive, Suite 400 Houston Lighting & Power  ;

Company Arlington, TX 76011 P. O. Box 61867 Houston, TX 77208 Lawrence E. Kokajko Project Manager Institute of Nuclear Power U.S. Nuclear Regulatory Commission Operations - Records Center [

Washington, DC 20555 13H15 700 Galleria Parkway Atlanta, GA 30339-5957. ,

Senior Resident Inspector l c/o U. S. Nuclear Regulatory Dr. Joseph.M. Hendrie Commission 50 Bellport Lane P. O. Box 910 Bellport, NY 11713 Bay City, TX 77414  :

D. K. Lacker J. R. Newman, Esquire Bureau of Radiation Control  !

Newman & Holtzinger, P.C., STE 1000 Texas Department of Health 1615 L Street, N.W. 1100 West 49th Street Washington, DC 20036 Austin, TX 78756-3189 D. E. Ward /T. M. Puckett U.S. Nuclear Regulatory Comm. .

Central Power and Light Company Attn: Document Control Desk P. O. Box 2121 Washington, D.C. 20555 Corpus Christi, TX 78403 J. C. Lanier/M. B. Lee Mark Proviano  ;

City of Austin Westinghouse Electric  ;

Electric Utility Department P. O. Box 355, ECE, 4-08 ,

721 Barton Springs Road Pittsburgh, PA 15230-0355 l Austin, TX 78704 i K. J. Fiedler/M. T. Hardt  !

City Public Service P. O. Box 1771 ,

San Antonio, TX 78296 I t

GLB\93-217.001 ,

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UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION ,

In the Matter )

) l' Houston Light' y & Power ) Docket Nos. 50-498 Company, et .1. , ) 50-499 '

)

South Texas Project )

Units 1 and 2 )_

4 AFFIDAVIT I, T. H. Cloninger, being duly sworn, hereby depose and say -

that I am V!ce President, Nuclear Engineering, of Houston Lighting ,

& Power Company; that I am duly authorized to sign and file with ,

the Nuclear Regulatory Commission the attached response to Generic  !

Letter 93-04; that I am familiar with the content thereof; and that the matters set forth therein are true and correct e/best of my knowledge and belief. /

A T '. H. C 6nInger ~ - '

N m Vice Nucle P r esident, Eng1 eer [ing STATE OF TEXAS )

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) j Subscribed and sworn to be, fore me, a Notary Publ~c in and ~~

for the State of Texas, this d day of /A1 4 M _.

, 1993.

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Houston Lighting & Power Company South Texas Project Dectric Generating Station ST-HL-AE-4533 File No. G03.08 10CFR50.54(f)

Page 4 Houston Lichtina & Power 45 day response to GNL 93-04 fas amended by July 26 NRC letter to Mr. Roger Newton)

Introduction Generic Letter 93-04 originally required each addressee to,

1) Within 45 days from the date of the generic letter a) Provide an assessment of whether or not the licensing  :

basis for each facility is still satisfied with regard to the requirements for system response to a single failure in the rod control system and - provide a supporting discussion for the assessment in light of the information  !

generated as a result of the Salem event.

b) If the assessment in 1(a) indicates that the licensing basis is not satisfied i) Provide an assessment of the impact of potential ,

single failures in the rod control system on the licensing basis of the facility.

ii) Describe any compensatory short term actions taken '

or that will be taken to address the actual or potential degraded or nonconforming conditions such as:

1) Additional cautions or modificatior.s to surveillance and preventive maintenance procedures. ,

2) Additional administrative controls for plant startup and power operations

3) Additional instructions and training to heighten operator awareness of potential rod control system failures and to guide operator response in the event of a rod control system malfunction

2) If the assessment in 1(a) indicates that the licensing basis is not satisfied, within 90 days from the date of the generic letter provide a plan and schedule for the long term resolution of this issue.

GLB\93-217.001

Houston Lighting & Power Company South Texas Project Electric Generating Station ST-HL-AE-4533 File No. G03.08 i 10CFR50.54(f) '

Page 5 Subsequent correspondence between the Westinghouse Owners Group ,

(WOG) and the NRC resulted in schedular relief for Required Responses 1.a., and 1.b.i. (NRC letter to Mr. Roger Newton dated July 26, 1993). These portions of the required actions will now be included with the 90-day licensee response. Also included in the NRC letter to Mr. Roger Newton dated July 26, 1993, was an additional requirement for the 45 day licensee response.

This additional requirement is that each affected licensee provide a summary of the results of the generic safety analysis program ,

conducted by the Westinghouse Owners Group and provide a discussion  !

of the applicability of the WOG generic safety analysis program results to their facilities.

South Texas Proiect (STP) Response to Item 1.b.ii Compensatory Actions The purpose of this discussion is to provide a response to the three areas of compensatory short-term actions identified by NRC r Required Response 1.b.ii.

1.b.li.1. " additional cautions or modifications to surveillance and preventive maintenance procedures" -

South Texas Project Units 1 and 2 are currently in extended outages. Between now r.nd the date of the ,

required 90 day licensee response, September 20, 1993,  !

STP Units 1 and 2 will operate only in Modes 3 through 6 or be defueled.

HL&P is implementing the following two temporary actions to mitigate the postulateri consequence to the two STP  ;

units of an event similar to the Salem event. ,

4 A) The boron concentration in the Reactor Coolant ,

i System will be maintained greater than or equal to -

2500 ppm to allow movement of control rods while in ,

Modes 3 through 6. This boron concentration will i maintain the reactor subcritical regardless of rod position if any rod control malfunction were ,

to occur. The affected procedures have been  !

changed to require a boron concentration of greater than or equal to 2500 ppm in the prerequisites.

CLB\93 217.001 i

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. j Houston Lighting & Power Cornpany S uth Texas Project Electric Generating Station ST-HL-AE-4533 File No. G03.08 10CFR50.54(f)

Page 6 i'

B) Operations personnel have installed a caution tag '

on the manual reactor trip breaker switches to ensure that work (in Modes 3 through 6) which may request RCCA withdrawal for rod control '

troubleshooting is not performed with less than ,

2500 ppm boron concentration in the Reactor Coolant l

System. >

South Texas Project Unit 2 is currently defueled and is not projected to be refueled prior to January of 1994. The two temporary actions listed above are therefore not currently applicable to Unit 2.

4 If HL&P determines that procedure changes are required prior to reducing the boron concentration or to entering modes 1 or 2, these changes will be presented to the NRC in HL&P's 90 day licensee response to GNL 93-04.

1.b.ii.2. " additional administrative controls for plant startup and power operation" -  !

, As stated earlier, HL&P does not plan to take either '

1 South Texas Project Unit 1 or 2 to Modes 1 or 2 prior to the date of the required 90 day licensee response to GNL  ;

93-04, September 20, 1993. If HL&P determines that  !

additional administrative controls are required for plant J

startup or power operation, these administrative controls will be presented to the NRC in HL&P's 90 day licensee response to GNL 93-04.

1.b.ii.3. " additional instructions and training to heighten  ;

operator awareness of potential rod control system  !

failures and to guide operator response in the event of I a rod control system malfunction" -

HL&P is implementing the following compensatory actions  !'

to ensure that all reactor operators are familiar with the Salem event and the concerns associated with the i

possible single failure vulnerability of the Westinghouse rod control system.

A) All licensed Unit 1 operators were trained on the Salem rod control event.

B) The Salem rod control event will be included in the Lessons Learned portion of licensed operator requalification training. This training will be complete by September 15, 1993.

GLB\93-217.001

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I Houston Lighting & Power Company Sou'th Texas Project Electric Generating Station ST-HL-AE-4533 File No. G03.08 10CFR50. 54 (f)

Page 7 The corrective action for this event has not been determined.

l Westinghouse and the WOG are investigating the root cause and resolution to the single failure event. STP will resolve the concerns after action by Westinghouse and WOG.

Summary of WOG Generic Safety Analysis Program As part of the Westinghouse Owners Group initiative, the WOG Analysis subcommittee is working on a generic approach to demonstrate that for all Westinghouse plants there is no safety significance for an asymmetric RCCA withdrawal. The purpose of the i program is to analyze a series of asymmetric rod withdrawal cases >

from both suberitical and power conditions to demonstrate that DNB does not occur.

A three dimensional spatial kinetics using the LOFTS, SPNOVA and THINC IV computer codes is being used to determine the impact of an asymmetric rod withdrawal on DNB. A detailed summary of this program can be found in WOG 1etter WCAP-13803 " Generic Assessment of Asymmetric Rod Cluster Control Assembly Withdrawal".

WOG Procram Results and Anolicability to South Texas Proiect Units 1 and 2.

l HL&P believes that the WOG methodology can be applied to STP.

Preliminary results from the WOG study have shown that, even for  ;

the worst case of asymmetric rod withdrawal DNB does not occur.

HL&P is currently in the process of verifying that the generic j l analysis is correctly applied to STP. j 1

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GLB\93-217.001 l