IR 05000498/1993042
| ML20058B763 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 11/19/1993 |
| From: | Johnson W NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | |
| Shared Package | |
| ML20058B732 | List: |
| References | |
| 50-498-93-42, 50-499-93-42, NUDOCS 9312020213 | |
| Download: ML20058B763 (7) | |
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APPENDIX U.S. NUCLEAR REGULATORY COMMISSION
REGION IV
NRC Inspection Report No.:
50-498/93-42 50-491/93-42 License Nos.: NPF-76 NPF-80
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Licensee: Houston Lighting 3 Power Company P.O. Box 1700 Houston, Texas 77251
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Facility Name:
South Texas Project Electric Generating Station (STPEGS),
Units 1 and 2 Inspection At: Matagorda County, Texas Inspection Conducted: November 1-3, 1993 Inspectors: Mark A. Satorius, Project Engineer, Project Section A, Division of Reactor Projects
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W. D. Johnson / Chief, Project Section A Date Inspection Summary Areas Inspected (Units 1 and 2):
Routine, announced inspection to resolve the issue of testing tornado dampers installed on safety-related heating, ventilation, and air conditioning (HVAC) systems.
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Results (Units 1 and 2):
The inspector concluded that no further review of tornado damper issues
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was required prior to the restart of Unit I and that Restart Issue 15 could be considered resolved (Section 6.1).
i Summary of Inspection Findings:
Inspection Followup Item 498;499/9331-76 was closed (Section 6.1).
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Attachments:
Attachment 1 - Persons Contacted and Exit Meeting
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[312O20213931339 R
ADOCK 0500049s PDR l
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I DETAILS
1 BACKGROUND
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Both units at STPEGS were shut down in early February 1993 and remain shut
down as a result of numerous broad scope problems identified by the NRC and
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the licensee.
NRC Inspection Report 50-493/93-31; 50-499/93-31
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identified 16 Restart Issues that required rese *t<un prior to the restart of
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Unit 1.
In addition to these Restart Issues, a number of items ralated to
these Restart Issues were identified. The purpose of this inspection was to determine the licensee's effectiveness in addressing Restart Issue 15,
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" Tornado Damper Issues," and to establish a basis for concluding that this
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Restart Issue has been adequately resolved by the licensee.
During the Diagnostic Evaluation Team (DET) Inspection, the DET identified the
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following issue concerning tornado dampers:
I Failure of tornado dampers could prevent cooling of safety-related
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components and systems. Thirty dampers had not been tested to verify
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their designed operation. The licensee agreed to test the dampers. NRC-
will evaluate-the licensee's test procedures and results.
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This inspection reviewed the. licensee's tests and results to determine whe'ther
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a regulatory requirement existed that would have' required preservice testing and subsequent periodic testing following installation.
Fifteen tornado dampers were installed in each unit at-STPEGS. The dampers installed were:
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STPEGS IDENTIFICATION NUMBER
DAMPER DESCRIPTION (UNIT 1/ UNIT 2)
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Control Room Outside Air Intake 3V111VDA075/3V112VDA075 Electrical Auxiliary Building (EAB)
3V111VDA077/3V112VDA077
Elevator Machine Room Exhaust EAB Elevator Machine Room Supply 3V111VDA078/3V112VDA078 EAB HVAC Exhaust 3V111VDA076/3V112VDA076 Fuel Handling Building (FHB) Supply 3V101VDA052/3V102VDA052 Mechanical Auxiliary Building (MAB)
3V101VDA118/3V102VDA118 Main HVAC Supply
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MAB Main HVAC Supply 3V101VDA119/3V102VDAl'19
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-3-MAB Main HVAC Supply 3V10lVDA120/3V102VDA120 Plant Exhaust Stack 3V10lVDA113/3V102VDA113 Reactor Containment Building (RCB)
3V141VDA001/3V142VDA001 Purge Supply Tendon Gallery Exhaust 3V141VDA298/3V142VDA298
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Technical Support Center (TSC) HVAC 3Vll1VDA277/3V112VDA277 Exhaust TSC HVAC Supply 3V111VDA276/3V112VDA276 TSC Outside Air Intake-3V111VDA302/3Vil2VDA302 TSC Smoke Purge "xhaust 3V111VDA275/3V112VDA275 2 DAMPER TESTING REQUIREMENTS (92720)
The inspector reviewed the following STPEGS documents to determine what testing was required to be performed on the tornado dampers.
Technical Specifications e
Updated Final Safety Analysis Report
Design Basis Document for the EAB HVAC Systan (5V119VB1022)
Design Bnis Document for the FHB HVAC System (5V129VB0116)
e Design basis Document for the MAB HVAC System (5V109VB0110)
Design Basis Document for the RCB HVAC System (2V149VB0114)
Tornado Damper Vendor Manual (American Warming and Ventilating, Inc.,
Document 80278-722)
Bechtel Specifications for Safety Class Dampers (3V289VS0008)
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The Bechtel Specification required that the damper vendor conduct a postfabricat'on shop test consisting of cycling the tornado dampers 25 times to ensure fr<!edom of movement.
In addition to these tests, the Bechtel specification required that the vendor test one Unit I supply and one Unit 1 i
exhaust tornado da;nper for leak rate and blade defection (no requirement was specified for conducting these later tests on any Unit 2 tornado damper). The inspector reviewed the vendor test packages and determined that all of these
vendor required tests had been completed satisfactorily.
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-4-Further review revealed that only the design basis documents referred to any type of postinstallation periodic testing. The design basis documents stated that all tornado dampers were required to be manually stroked as part of scheduled maintenance to assure damper operahility. A review of preventive and corrective maintenance conducted on the campers since installation was unable to confirm that the dampers had ever been cycled following installation.
Discussions with the system engineer, who was familiar with the licensee's HVAC systems since damper installation, stated that to his
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knowledge, the tornado dampers had never been cycled during any maintenance activity.
3 TORNADO DAMPER MAINTENANCE ACTIVITIES (92720)
Following the DET's identification of the tornado damper testing issue, the licensee revised all of the periodic preventive maintenance procedures to include stroking of the dampers.
Previously, these procedures performed cleaning, lubrication, and inspection, on an 18-to 24-month periodicity, and did not cycle the dampers to ensure freedom of operation. The maintenance procedure currently utilized by the licensee include:
STPEGS IDENTIFICATION NUMBER WORK INSTRUCTION (UNIT 1/ UNIT 2)
FREQUENCY (UNIT 1/ UNIT 2)
3V111VDA075/3V112VDA075 24 Months 93000484/485 3V111VDA077/3Vil2VDA077 24 Honths 93000498/499 3V111VDA078/3Vil2VDA078 24 Months 93000500/501 3V111VDA076/3V112VDA076 24 Months 93000495/496 3V10lVDA052/3V102VDA052 Outage 93000493/494 3V10lVDAll8/3V102VDAll8 Outage 93000518/519 3V10lVDA119/3V102VDA119 Outage 9300C518/519 3V10lVDAl20/3V102VDA120 Outage 93000518/519 3V10lVDAll3/3V102VDA113 Outage 93000491/492 3V141VDA001/3V142VDA001 Outage 93000516/517 3V141VDA298/3V142VDA298 Outage 93000514/515 3VlllVDA277/3V112VDA277 24 Months 93000504/505 W 11VDA276/3Vll2VDA276 24 Months 93000509/510
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-5-l 3V111VDA302/3Vll2VDA302 24 Months 93000502/503
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SVillVDA275/3V112VDA275 24 Months 93000504/505 The inspector reviewed these procedures and concluded that the changes would be effective to ensure free damper operation.
This preventive maintenance had been performed on all of the Unit I tornado
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dampers, and 11 of the 15 tornado dampers installed in Unit 2, with the i
remaining 4 to be completed prior to the Unit 2 restart.
Some relatively minor damper stiffness was documented on Unit 1 Dampers 3V101VDA118, 119, and 120 on August 25, 1993. This identified deficiency was worked under Service
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Request (SR) 92058 and consisted of lubricating and then manually cycling the dampers several times.
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Other problems developed during maintenance activities on Unit 1 Dampers 3V10lVDA052 and 3V101VDAll3. The problem encountered on Damper
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3V10lVDA052 consisted of some binding and bearing stiffness identified during l
the attempts to cycle the damper on October 23, 1993.
Because the functionality of this damper affected the operability of the FHB exhaust air system, Unit 1 entered Technical Specification 3.9.12, when operators declared
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all trains of the FHB exhaust air system inoperable. These problems were dispositioned by SR 210277, which was worked October 25, 1993, and consisted of lubricating and exercising the damper. This activity was successful in loosening the damper bearings.
The problem discovered with Damper 3V101VDAll3 consisted of difficulties with cycling the damper and obta'ning spring tension values ussng a dynamometer during maintenance performes on T tober 22, 1993.
Damper 3V10lVDAll3, which
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was not equipment governed uador Technical Specifications, consisted of four i
damper sections, each section being a self-contained unit with its own blades and actuation spring. During repair activities worked under SR 210282 on i
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October 25, 1993, two of the sections satisfactorily cycled. The other two sections were capable of cycling; however, due to an interference problem between the spring operator and a portion of the damper frame, maintenance
personnel were unable to measure the closing tension using the dynamometer.
After resolving the interference pro'olems, the damper (all four sections) was successfully cycled and the tension data recorded.
The licensee analyzed both latter damper problems and determined that both dampers in their as-found condition would have been able to perform their safety function under tornado conditions.
The inspector concluded that this determination was appropriate.
4 PROCEDURAL ENHANCEMENTS (92720)
The licensee was in the process of changing the periodic preventive maintenance procedures to collect quantitative values for damper spring tension in order to conduct trending analysis of tornado damper performance.
The inspector reviewed the maintenance feedback requests that were intended to
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accomplish this activity. Other procedural imprevements included changing i
Procedure OPOP04-ZO-0002, Revision 3, " Severe Weather Guidelines," to require i
that following any close tornado strike, all tornado dampers will be inspected and cycled, in accordance with the preventive maintenance procedures. _In addition to this change, a second change to Procedure OPOPO4-ZO-0002 provides
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guidance that, following any close tornado strike, specific HVAC exhaust fans
will be secured in order to ensure that all tornado dampers that may have j
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l 5 GENERIC TORNADO DAMPER CONSIDERAi!ONS j
Outside the scope of this impection, the Office of Nuclear Reactor Regulation i
had initiated a study to generically evaluate the lack of testing requirements
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testing these dampers, either by periodic cycling or under simulated tornado i
conditions.
j 6 CLOSED ITEMS RELATED TO RESTART ISSUES (92701)
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6.1 (Closed) Inspection Followup Item 498:499/9331-76: Failure of tornado i
dampers could prevent coolina of safety-related components and systems
i This item was closed based on the licensee's corrective action described in
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7 ASSESSMENT OF MANAGEMENTS RECEPTIVENESS TO IDENTIFYING AND CORRECTING PLA!!T l
PROBLEMS (92720)
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The inspector determined that licensee management had respondad in a pror.ctive
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were appropriate and appeared to be taken in a manner commensurate with the safety significance of the issue.
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ATTACHMENT 1
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1 PERSONS CONTACTED i
l.1 Licensee Personnel
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V. Albert, Administrator, Engineering Projects, Plant Engineering Department i
D. Bize, Licensing Engineer, Nuclear Licensing i
T. Cloninger, Vice President, Nuclear. Engineering J. Conly, Licnesing Engineer, Nuclear Licensing J. Cottam, Engineering Supervisor, Plant Engineering Department
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M. Grim, Licensing Engineer, Nuclear Licensing J. Groth, Vice Presidant, Nuclear Generation S. Head, Deputy General Manager, Nuclear !icensing T. Jordan, General Manager, Nuclear Engineering
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J. Johnson, Supervisor, Nuclear Assurance
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M. Kanavos, Manger, Mechanical and Nuclear Engineering, Design Engineering-
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D. Leazar, Manager, Plant' Engineering Department
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L. Myers, Plant Manager,. Unit 1
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G. Parkey, Plant Mar.ager, Unit 2 i
M. Sicard, Unit Supervisor, Plant Operations M. Smith, Senior Consultant, Assessments S. Thomas, Assistant, Vice President Nuclear. Engineering
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In addition to the personnel listed above,' the inspectors contacted other personnel during this inspection period.
1.2 NRC Personnel
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M. Satorius, Project Engineer, Project Section A, Division of Reactor Projects J. Pellet, Chief, Operations Section, Division of Reactor Safety-The above listed licensee and NRC personnel attended the exit meeting.
2 EXIT MEETING An exit meeting was conducted cn October 22, 1993. During this meeting, the inspectors reviewed the sccpe and findings of this report. The licensee did not take exception with any of the inspection findings nor identify as proprietary any information provided to, or reviewed by, the inspectors, l
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