ML20035G280
| ML20035G280 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 04/19/1993 |
| From: | Milhoan J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | Cottle W HOUSTON LIGHTING & POWER CO. |
| Shared Package | |
| ML20035G281 | List: |
| References | |
| EA-93-047, EA-93-47, NUDOCS 9304270075 | |
| Download: ML20035G280 (5) | |
See also: IR 05000498/1993008
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NUCLEAR REGULATORY COMMISSION
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APR I 91993
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Dockets:
50-498; 50-499
Licenses:
EA 93-047
Houston Lighting & Power Company
ATTN: William T. Cottle, Group
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Vice President, Nuclear
P.O. Box 1700
[
Houston, Tex m 77251
SUBJECT:
NOTICE OF VIOLATION AND PROPOSED IMPOSITION OF CIVll PENALTY -
575,000 (NRC INSPECTION REPORT NO. 93-08)
This is in reference to the inspection conducted on February 17-26, 1993, at
Houston Lighting & Power Company's (HL&P) South Texas Project Electric
Generating Station (STP). A report documenting the results of this inspection
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was issued on March 17, 1993. As indicated in the report, this inspection
found apparent violations of requirements associated with HL&P's maintenance
and operation of motor-operated valves (MOV) in safety-related systems.
These
violations were discussed with you and other HL&P representatives during an
enforcement conference in the NRC's Arlington, Texas office on March 25, 1993.
The violations identified during this inspection include:
1) a failure to
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repair a failed motor on an MOV in the Low Head Safety Injection system for
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some 18 months, as well as a failure to determine the cause of the motor
failure to prevent a recurrence; 2) as a consequence of the above violation, a
f ailure to operate STP Unit 2 in accordance with the Technical Specification
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requirements related to the Low Head Safety Injection system; and 3) a failure
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to take prompt action to determine the cause of and correct an over-torque
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condition that was affecting five MOVs in the STP Unit 1 Residual Heat Removal
system.
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On February 9,1993, STP Unit 2 MOV SI-31A failed to open on demand from the
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control room.
During the subsequent investigation, HL&P determined that the
valve motor had burned up while attempting to lift the valve disc off the
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closed seat.
The area between the actuator springpack washers was found to
have been thoroughly packed with partially hardened and slightly discolored
grease, which was the most likely cause of the valve motor failure.
As a result of its investigation, HL&P discovered that the valve motor for
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MOV SI-31A had previously burned up during an attempt to open the valve in
April 1989. Although a work request was issued to replace the motor, no
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CERTIFIED Mall
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RETURN RECEIPT REQUESTED
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930427o07s 93o419
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APR 1 9 1993
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station problem report was issued; consequently, no effort was undertaken to
determim the root cause of the failure.
in addition, even though the motor
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failed in April 1989 and was again checked and determined to be shorted in
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November 1989, for reasons not fully understood by HL&P at the time of the
enforcement conference, the valve motor was not replaced until October 1990.
STP Unit 2 was operated f or a full fuel cycle with the motor to SI-3] A
Although operations personnel placed the valve in its normal
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operating position for reactor operation,
i.e., fully open with power removed
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from the motor, SI-31A was unable to perform its safety function.
Specifically, the design basis for SI-31A is to close approximately 13 hours1.50463e-4 days <br />0.00361 hours <br />2.149471e-5 weeks <br />4.9465e-6 months <br />
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following a loss-of-coolant accident to establish hot leg recirculation for
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Train A of the Low Head Safety Injection System.
The valve is inaccessible in
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a post-accident environment.
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The NRC recognizes that HL&P's after-the-fact analysis of this condition
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concludes that operators would have been able to take action to overcome the
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SI-31A failure and that the full safety function of the Low Head Safety
Injection system would have been retained, due to the robust design of the STP
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emergency core cooling system (three 100% ECCS trains).
Nonetheless, the NRC
considers Violations I.A and B of the enclosed Notice to be a significant
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regulatory concern because (1) a safety-related MOV went unrepaired for 18
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months, despite multiple opportunities to recognize the significance of the
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deficiency and take corrective action, and (2) operations personnel did not
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recognize the technical specification implications of operating the reactor
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with SI-31 A inoperable.
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During the enforcement conference HL&P asserted that its initial corrective
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actions in 1989 were reasonable in light of industry information available in
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that timeframe.
The NRC does not agree, but rather views HL&P's inaction in
1989 to be the result of a passive corrective action program in which
potentially significant equipment problems were not aggressively pursued.
In
fact, current inspection findings indicate that there have been other
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situations in which HL&P has not taken prompt action to determine the causes
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of safety-related MOV f ailures and deficiencies (as discussed during an NRC
exit meeting for Inspection Report 93-13, held on March 26,1993); thus, the
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issues surrounding SI-31A do not appear to be isolated concerns.
It appears
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that HL&P's corrective actions continue to often focus on only the symptoms of
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the problem and not the root cause.
In accordance with the " General Statement
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of Policy and Procedure for NRC Enforcement Actions," (Enforcement Policy)
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10 CFR Part 2, Appendix C, Violations 1.A and B have been categorized as a
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Severity Level 111 problem.
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HL&P has taken or has plans to take a number of necessary corrective actions
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aimed primarily at equipment operability and repair issues.
These actions
included:
1) repair of SI-31A: 2) modifications to the valve to prevent
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similar failures: 3) plans to review the operability tracking log and open
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service requests on Unit I prior to start-up; and 4) plans to enhance
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programmatic controls over operability determinations and equipment failure
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- Houstcn Lighting & Power Company
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APR I 9 1993
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trending.
With regard to its corrective action program, HL&P acknowledged
past weaknesses in its program, but contends that significant enhancements
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have been made to it since the occurrence of the events described above.
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While the NRC agrees that programmatic enhancements have been made, those
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enhancements have not been completely effective. Specifically, a number of
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recent violations were cited in Inspection Report 92-35 that involved
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inadequate corrective actions for known hardware or programmatic deficiencies.
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As discussed in the inspection report and during the enforcement conference,
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the NRC believes that HL&P's long-term corrective actions should include
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definitive plans for reviewing MOV lubrication issues, particularly since
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hardened grease was determined to be the apparent cause of the SI-31A motor
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failure.
The grease that had migrated into the springpack of Valve SI-31A was
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approximately five years in age.
In HL&P's MOV program, each springpack is
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inspected approximately once every five years.
Thus, it would be prudent to
examine the frequency of grease inspections in light of your experience and,
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as warranted, adjust the inspection intervals.
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To emphasize the importance of ensuring that identified problems that have the
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potential to affect the operability of safety systems are resolved in a timely
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manner, and are resolved commensurate with their relevance to ensuring
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compliance with plant Technical Specifications, I have been authorized, after
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consultation with the Director, Office of Enforcement, and the Deputy
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Executive Director for Nuclear Reactor Regulation, Regional Operations and
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Research, to issue the enclosed Notice of Violation and Proposed Imposition of
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Civil Penalty (Notice) in the amount of 575,000 for the Severity Level III
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problem described above and in the Notice. The base value of a civil penalty
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for a Severity Level III problem is 550,000. The civil penalty adjustment
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factors in the Enforcement Policy were considered as discussed below.
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Although the valve failure is considered a self-identifying event, the base
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civil penalty was mitigated by 25 percent in recognition of HL&P's having
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discovered the violations associated with the 1989 SI-31A failure while
investigating the 1993 event.
However, the base civil penalty was escalated
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by 25 percent for the corrective action factor because the NRC identified the
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broad concerns with the adequacy of HL&P's lubrication program.
In addition,
the civil penalty amount was escalated a further 50 percent for the added
significance of the duration that SI-31A remained inoperable without the
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Operation Department's recognition of its technical specification impact.
The
full 100 percent escalation was not applied for this factor in recognition of
the extra margin that you incorporated into your emergency core cooling
system.
The other adjustment factors in the Policy were considered and no
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further adjustment to the base civil penalty was considered appropriate.
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The remaining violation, addressed in Section II of the Notice, involved the
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failure to take prompt corrective action to address an over-torque condition
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for five motor-operated valves in the Residual Heat Removal system, and has
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been classified at Severity Level IV.
Although an after-the-fact examination
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and limited testing performed by a third party indicated that these valves may
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Houston Lighting'& Power Company
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APP I O racq
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have been capable of performing their safety function for a limited number of-
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cycles, the NRC is concerned that HL&P made an initial operability
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determination without performing an analysis, test, or a specific inspection
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of the load bearing components that were subjected to the over-torque
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condition.
This condition is of more then minor concern because it reduces
the number of cycles that the valve actuator can perform before failure and,
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if left uncorrected, could lead to a more serious safety concern.
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You are required to respond to this letter and should follow the instructions
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specified in the enclosed Notice when preparing your response.
In your
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response, you should document the specific actions taken and any additional
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actions you plan to prevent recurrence.
After reviewing your response to this
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Notice, including your proposed corrective actions, and the results of future
inspections, the NRC will determine whether further NRC enforcement action is
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necessary to ensure compliance with NRC regulatory requirements.
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In accordance with 10 CFR 2.790 of the NRC's " Rules of Practice," a copy of
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this letter and its enclosure will be placed in the NRC Public Document Room.
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The responses directed by this letter and the enclosed Notice are not subject
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to the clearance procedures of the Office of Management and Budget as required
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by the Paperwork Reduction Act of 1980, Pub. L. No.96-511'.
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Sincerely,
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O
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ames L. Milhoan
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.egional Administrator
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Enclosure:
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Notice of Violation and Proposed Imposition
of Civil Penalty
Houston Lighting & Power Company
ATTN: William J. Jump, Manager
Nuclear Licensing
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P.O. Box 289
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Wadsworth, Texas 77483
City of Austin
Electric Utility Department
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ATTN:
J. C. Lanier/M. B. Lee
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P 0. Box 1088
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, Houston Lighting & Power Company
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APR 1 9 19X3
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City Public Service Board
ATTN:
R. J. Costello/M. T. Hardt
P.O. Box 1771
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San Antonio, Texas 78296
Newman & Holtzinger, P. C.
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ATTN: Jack R. Newman, Esq.
1615 L Street, NW
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Washington, D.C.
20036
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Central Power and Light Company
ATIN:
D. E. Ward /T. M. Puckett
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P.O. Box 2121
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Corpus Christi, Texas 78403
Records Center
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1100 Circle 75 Parkway
Atlanta, Georgia 30339-3064
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Mr. Joseph M. Hendrie
50 Bellport Lane
Bellport, New York 11713
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Bureau of Radiation Control
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State of Texas
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1101 West 49th Street
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Judge, Matagorda County
Matagorda County Courthouse
1700 Seventh Street
Bay City, Texas 77414
Licensing Representative
Houston Lighting & Power Company
Suite 610
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Three Metro Center
Bethesda, Maryland 20814
Houston Lighting & Power Company
ATTN:
Rufus S. Scott, Associate
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General Counsel
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P.O. Box 61867
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Houston, Texas 77208
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Houston Lighting & Power Company
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IPR 191933
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