ML20073D909
| ML20073D909 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 09/22/1994 |
| From: | Groth J HOUSTON LIGHTING & POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| EA-93-047, EA-93-47, NUDOCS 9409280128 | |
| Download: ML20073D909 (7) | |
Text
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The Light company wt exas Pr ject ectdc Generating Station P. O. Box 289 Wadswonh, Texas 77483 Houston Lighting & Power September 22, 1994 ST-HL-AE-4898 File No.:
G02.04 10CFR2.201 Director, Office of Enforcement U.
S. Nuclear Regulatory Commission Attention:
Document Control Desk Washington, DC 20555 South Texas Project Units 1 and 2 Docket Nos. STN 50-498; STN 50-499 Reply to Notice of Violation and Proposed Imposition of Civil Penalty, Revision 1 Inspection Report 93-08; Enforcement Action 93-047 Houston Lighting & Power Company has reviewed the Notice of Violation and Proposed Imposition of Civil Penalty dated April 19, 1993, and submits the attached revised reply to violations I.A.
Houston Lighting & Power did not protest the proposed civil penalty, and an electronic wire transfer has been made, payable to the Treasurer of the United States, for this civil penalty.
In the cover letter to the Notice of Violation, the Nuclear Regulatory Commission recommended that Houston Lighting & Power examine the frequency of grease inspections for motor operated valves.
Houston Lighting Power believes that the current inspection interval is adequate.
Current diagnostic testing now includes a process called " pack mate" that compresses the spring pack to assure proper operation.
Compression of the spring pack essentially removes the old grease and precludes accumulation of old grease.
Hence, with the " pack mate" process as part of the diagnostic testing, inspection frequency is adequate to assure that hardened grease does not accumulate in the motor operated valve spring packs.
Houston Lighting & Power believes that grease hardening was not the primary factor in the original valve motor failure.
Motor failure was due to thermal binding / pressure locking of the valve gate in the valve body as a result of rapid cooling of the valve body when the valve was closed.
This information was provided to members of the Regional Staff during the process of the Unit 1 and 2 Restart inspections.
This revision documents the Houston Lighting & Power change in the identified cause of the SI-31A valve motor failure.
IR 94\\9 g1M 001,pm;,et Manaper nn Behalf of the Participants in the South Texas Project l
9409280128 940922 U
PDR ADOCK 05000499 O
i 1
Houston Lighting & Power Company South Texas Project Electric Generating Station ST-HL-AE-4898 l
Page 2 l
l If you have any questions, please contact S.
M.
Head at (512) 972-7136 or me at (512) 972-8664.
L F.
roth l
l Vice President, Nuclear Generation DNB/esh Attachments:
1.
Affidavit 2.
Reply to Notice of Violation and Proposed I
Imposition of Civil Penalty EA 93-047, Violation I.A.
9 4
IR-94\\94-147.001
~
l Houston Lighting & Power Company ST-HL-AE-4898 South Texas Project Electric Generating Station File No.:
G02.04 Page 3 c:
Leonard J.
Callan Rufus S.
Scott Regional Administrator, Region IV Associate General Counsel U.
S. Nuclear Regulatory Commission Houston Lighting & Power Company 611 Ryan Plaza Drive, Suite 400 P.
O.
Box 61067 Arlington, TX 76011 Houston, TX.77208 l
Lawrence E.
Kokajko Institute of Nuclear Power l
Project Manager Operations - Records Center l
U.
S.
Nuclear Regulatory Commission 700 Galleria Parkway I
Washington, DC 20555-0001 13H15 Atlanta, GA 30339-5957 l
l David P.
Loveless Dr. Joseph M. Hendrie Sr. Resident Inspector 50 Bellport Lane i
l c/o U.
S.
Nuclear Regulatory Comm.
Bellport, NY 11713 P.
O.
Box 910 Bay City, TX 77404-910 Richard A.
Ratliff Bureau of Radiation Control J.
R. Newman, Esquire Texas Department of Health l
Newman, Bouknight & Edgar, P.C.
1100 West 49th Street STE 1000, 1615 L Street, N.W.
Austin, TX 78756-3189 Washington, DC 20036 i
l U.
S.
Nuclear Regulatory Comm.
K. J. Fiedler/M. T. Hardt Attn: Document Control Desk City Public Service Washington, D.
C.
20555-0001 P.
O.
Box 1771 San Antonio, TX 78296 J.
C. Lanier/M.
B.
Lee J.
R.
Egan, Esquire City of Austin Egan & Acsociates, P.C.
Electric Utility Department 2300 N Street, N.W.
721 Barton Springs Road Washington, D.C.
20037 Austin, TX 78704 G.
E. Vaughn/C. A. Johnson Central Power and Light Company P.
O.
Lox 2121 l
Corpus Christi, TX 78403 l
l l
l I
ST-HL-AE-4898 Page 1 of 1 UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION In the Matter
)
)
Houston Lighting & Power
) Docket Nos. 50-498 Company, et al.,
)
50-499
)
South Texas Project
)
Units 1 and 2
)
AFFIDAVIT I, J.
F. Groth, being duly sworn, hereby depose and say that I am Vice President, Nuclear Generation, of Houston Lighting &
Power Company; that I am duly authorized to sign and file with the Nuclear Regulatory Commission the attached Reply to Notice of Violation and Proposed Imposition of Civil Penalty (Nuclear Regulatory Commission Inspection Report 93-08; Enforcement Action 93-047); that I am familiar with the content thereof; and that the matters set forth therein are true and correct to the best of my knowledge and belief.
F. Gro'th
'.ce President, uclear Generation STATE OF TEXAS
)
)
)
1 Subscribedandsworntobeforeme,dg[g1994.
a Notary Public in and for the State of Texas, this J28 day o n w 0 ?h G nuM11-p%w.t coat McsTG0MERY U
Y v ;-
sew, Na tt.t. e rm, y
State of Texa
.-(D/ Wy Comme,vtin Eores 06 2045
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IR-94\\94-147.001
l ST-HL-AE-4898 Page 1 of 3 Reply to Notice of Violation and Proposed Imposition of Civil Penaltv EA 93-047. Violation I.A.
I.
Statement of Violation I.A:
10 CFR 50, Appendix B, Criterion XVI, states that " measures shall be established to assure that conditions adverse to quality, such as failures, malfunctions, deficiencies, deviations, defective material and equipment, and nonconformances are promptly identified and corrected.
In the case of significant conditions adverse to quality, the measures shall assure that the cause of the condition is determined and corrective action taken to preclude repetition.
The identification of the signiCicant condition adverse to quality, the cause of the condition, and the l
corrective action taken shall be documented and reported to j
appropriate levels of management."
Contrary to the above, in April 1989 and November 1989, the licensee identified a significant condition adverse to quality related to an inoperable motor on Unit 2 safety-related valve SI-31A, but did not replace the motor until October 1990.
Further, the licensee did not determine the cause of the failure and take action to preclude recurrence, or document and report the condition to appropriate levels of management until the motor failed again under similar circumstances on February 9, 1993.
II.
Houston Lichtina & Power Position, Violation I.A:
Houston Lighting & Power concurs that the cited violation occurred.
1 III.
Reason for Violation I.A:
The cause of this event was less than adequate operability determination and identification of corrective actions to correct t
the root causes of motor failures.
t IV.
Corrective Actions, Violation I.A:
1.
Houston Lighting & Power has made significant improvements to the Operability Determination process since occurrence of the original event.
The motor operated valve motor failure on February 9,
- 1993, which was correctly determined to be inoperable under the current process, demonstrates that the improvements made to this process assure that appropriate operability determinations are being made.
IR-94\\94-347.001 i
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ST-HL-AE-4898 Page 2 of 3 Reolv to Notice of Violation and Proposed Imposition of Civil Penaltv EA 93-047, Violation I.A.
IV.
Corrective Actions, Violation I.A: (Cont'd) 2.
Houston Lighting & Power reviewed historical operability tracking logs and a sample of key safety related service requests to determine if there were any additional cases of improper operability determination for either Unit.
The purpose of this review was to determine if historical operability issues existed.
This review was completed on June 9, 1993, with follow-up issues resolved on September 14, 1994.
Additionally, the System Certification Process for restart of each Unit provided additional confidence that equipment will perform satisfactorily.
3.
Houston Lighting & Power upgraded the program used to analyze and trend equipment history to assure that repetitive component failures are identified, and appropriate corrective actions are taken to prevent recurrence.
This program change was initially implemented on October 15, 1993.
l V.
Additional Information:
The failure of the ' motor on SI-31A on February 9,
1993, was initially attributed to grease hardening in the spring pack.
Houston Lighting & Power initially believed that grease hardening in the spring pack caused the motor operated valve torque switch to delay motor tripping at the appropriate torque level and the i
motor operated valve was shut with excessive force.
The motor was believed to have failed later while attempting to open the motor operated valve due to this presumed closure with excessive i
force. This initial cause determination was questioned in August
)
of 1993, when testing was performed to determine if thermal i
binding of the valve was the cause of motor failure.
The empirical tests demonstrated that the valve body was cooled l
f aster than the valve gate, which led to binding of the gate when commanded to open before the gate had reached an equilibrium temperature.
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I IR-94\\94-147.001
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ST-HL-AE-4898 Page 3 of 3 Reolv to Notice of Violation and Proposed Imoosition of Civil Penaltv EA 93-047. Violation I.A.
V.
Additional Information: (Cont'd)
To address the generic implications of this failure, a revision to Operations Procedure (OPGP02-RH-0001) was completed to provide enhanced direction to prevent future thermal binding / pressure locking of the SI-031 Valves. A special test (ITEP07-RH-001) was performed to confirm the adequacy of the procedure changes.
Results were satisfactory.
In
- addition, a
thermal binding / pressure locking checklist was included in the design basis reviews which were part of the Generic Letter 89-10 effort at STP (Procedure EI 4.06).
Houston Lighting & Power initially assessed the motor operated valves with actuators that rely on a torque switch to turn off the motor.
Of ninety-eight motor operated valves in Units 1 and 2 that were actuated by torque switches, only thirteen motor operated valves in Unit 1 had not been diagnostically tested. The thirteen Unit 1
motor operated valves were subsequently diagnostically tested.
At the end of 2RE03, each of the Unit 2 motor operated valves had been diagnostica11y tested.
The diagnostic tests demonstrated that the spring packs were functioning properly and not experiencing hydraulic effects from grease or hardened grease in the spring pack.
Houston Lighting & Power has additional assurance that hardened grease in the motor operated valve spring pack will not be a problem because the diagnostic tests included a process called i
" pack mating" where the spring pack was removed from the actuator and compressed to verify that it performed to manufacturers' specifications.
If hardened grease is in the spring pack, then l
l the process indicates an anomaly through increased stiffness or l
less than minimum compression.
The " pack mate" process, because of the compression, squeezes the old grease out of the spring i
j pack.
l VI.
Date of Full Comoliance. Violation I.A:
Houston Lighting & Power is in full compliance.
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r IR-94\\94-147.001