ML20077E258
| ML20077E258 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 12/07/1994 |
| From: | Querio R COMMONWEALTH EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9412120207 | |
| Download: ML20077E258 (6) | |
Text
S Commonwnhh Edison LaSalls Coun., Nucisar Station 2601 N. 21st Road Marseilles, Illinois 81341 Telephone 815/357 6761 December 7,1994 United States. Nuclear Regulatory Commission Washington, D.C. 20555 Attention:
Document Control Desk
Subject:
LaSalle County Station Units I and 2 Response to Notice of Violation Inspection Report Nos. 50-373/94016; 50-374/94016 NRC Docket Numbers 50-373 and 50-374.
Reference:
- 1. E. G. Greenman letter to R.E. Querio, Dated ),ovember 9,1994, Transmitting NRC Inspection Report 50-373/94017; 50-374/94017.
Enclosed is Commonwealth Edison Company's response to the Notice of Violation (NOV) that was transmitted with the Reference I letter and NRC Inspection Report Nos. 50-373/94017; 50-374/94017.
Peference 1 identified one viobtion concerning incorrectly oriented flow orifices.
The root cause of this violation was ineffective and untimely corrective actions. LaSalle County Station has recognized the need to focus on the completeness and quality ofinitial corrective actions. Our recent efforts have concentrated on making our corrective action system function in a timely and proactive manner. In the past it was not always customary among engineering personnel to seek a root cause beyond the immediate failure.
Our newly created Material Condition Group will help provide a special focus on root cause analysis and add a further enhancement to performance trending. This new group will now provide an oversight to the root cause evaluations that are being performed at LaSalle and provide the impetus for timely and effective corrective actions.
j This is a part of the ongoing effort at LaSalle to correct long standing station problems j
and preclude their recurrence. The effective implementation of the Material Condition i
Group will provide the timely corrective actions we need to prevent violations of this type from occurring.
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i-If there are any questions or comments concerning this letter, please refer them to me at (815) 357-6761, extension 3600.
Respectfully,
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9 R. E. Querio Site Vice President LaSalle County Station cc:
J. B. Martin, Regional Administrator, Region III W. D. Reckley, Project Manager, NRR P. G. Brochman, Senior Resident Inspector, LaSalle D. L. Farrar, Nuclear Regulatory Services Manager, NORS Central file i
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ATTACllMENT RESPONSE TO NOTICE OF VIOLATION NRC INSPECTION REPORT 50-373/94017, 50-374/94017 VIOLATION: 373(374)/94017-01 During an NRC inspection conducted on August 20 through October 7,1994, a violation ofNRC requirements was identified. In accordance with the " General Statement of Policy and Procedure for NRC Enforcement Actions," 10 CFR Part 2, Appendix C, the violation is listed below:
Title 10 of the Code offederalRegulations, Part 50, Appendix B, Criterion XVI, states, in part, 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."
Contrary to the above, and for a period of over ten years from 1983 through August 3,1994, the licensee did not promptly identify, nor take the proper actions to correct, several plant systems' flow measuring orifices, which were installed backwards.
Specifically:
1.
On June 9,1982, Zion Station notified all Comed nuclear stations that reactor coolant loop resistance temperature detector flow orifices were found installed backwards on Unit 2. On August 3,1983, the two resultant LaSalle action item records (AIR) were closed based on verification of correct orifice orientation during initial plant construction and preoperational testing.
2.
On October 5,1990, NRC Information Notice (IN) 90-65 notified all power reactor licensees of recent problems associated with orifice misorientation. The resultant LaSalle Nuclear Tracking System (NTS) Item No. 373-103 90-06501 was closed based on the previous AIRS and IN 90-65 not applying to LaSalle.
3.
On February 21,1994, LaSalle Station's Unit 2 reactor core isolation cooling (RCIC) system isolated due to a burst rupture disc. The licensee determined part of the root cause was a drain line orifice improperly installed on the steam exhaust drain line. A planned corrective action to evaluate other systems for improper orifice installation was not timely.
4.
Between July 25 and August 3,1994, NRC inspectors identified flow measuring l
orifices installed backwards on the Units 1 and 2 fuel pool emergency make up pump lines, the Unit 2 low pressure core spray system discharge line, and the Unit 2 drywell floor drain discaarge line.
This is a Severity Level IV violation (Supplement I).
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ATTACIIMENT (Continued)
RESPONSE TO NOTICE OF VIOLATION NRC INSPECTION REPORT 50-373/94017, 50-374/94017 REASON FOR VIOLATION: 373(374)/ 94017-01 On July 25,1994, the LaSalle IDNS inspector discovered flow orifices (l(2)FE038) for the Unit I and Unit 2 fuel pool emergency make-up pumps 1(2)FC03PA apparently installed incorrectly. The " inlet" indication, stamped on the tongue of the orifice plate, was observed to be facing downstream of the direction of flow. The observed configuration would indicate that the orifice is installed backwards. On July 26, 1994, the inspector observed the flow orifice (2E21-N002) for the Unit 2 LPCS pump apparently installed incorrectly.
LaSalle Station had been notified of the possibility ofincorrectly installed orifices and the effects through NRC Information Notice No. 90-65, "Recent Orifice Plate Problems", issued October 5,1990. The LSCS response (AIR 373-103-90-06501) indicated that correct installation of orifices was performed by Construction and controlled through conformance to the design drawings. The AIR response did not indicate whether any physicalinspections were performed to verify orifice installations. As evidenced by the current events, the response to this AIR was clearly inadequate.
For LPCS,1(2)E21-N002 measures pump discharge flow which is also used for bypass flow control. Measured pump discharge flow must meet Tech Spec Requirement 4.5.1.b.l. For the fuel pool emergency make-up pumps,1(2)FE038 measures pump discharge flow which is used for ASME Section XI ISI testing, per Tech Spec 4.0.5.
Since the orifice provides consistent flow data,Section XI requirements are met.
Tech Specs requires the LPCS pump develop a flow of at / cast 6350 gpm against a test line pressure ofgreater than or equal to 290 psig. Based on the qualitative analysis results and the requirements of Tech Specs, sensed LPCS pump discharge flow error is in the conservative direction. Tech Specs does not provide any flow requirements for the fuel pool emergency make-up pumps. ASME Section XI ISI testing requirements are met, since the program concentrates on trending equipment data. A review of past maintenance history indicates no maintenance / removal has been performed on the orifices in question, since initial installation.
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ATTACIIMENT (Continued)
RESPONSE TO NOTICE OF VIOLATION NRC INSPECTION REPORT 50-373/94017,50-374/94017 CORRECTIVE ACTIONS TAKEN AND RESULTS ACIIIEVED (373(374)/94017-01):
System Engineering recognized that incorrect orientation could have an impact on a number of plant systems. It was decided that the possible impact on ECCS Systems would be evaluated first. After this step was complete, a review of Tech Specs requirements for all other safety-related systems impacted would be performed.
The next action performed was an engineering evaluation to determine the efTect on flow measurement due to incorrect position of a flow orifice. Orifice dimensions and design (i.e. square-edged vs. beveled-edge) could not be determined since no orifice drawings could be located. Therefore, initially, a qualitative analysis was performed assuming a bevel-edged orifice.Results of this review indicated that a bevel-edged orifice, installed backwards in the flow stream, would result in measured flow (sensed) that is lower than the actual flow. The actual differential pressure for a beveled-edge orifice plate will be lower when it is installed backwards. The fluid velocity profile is smoothed or
" contoured" by the tapering of the bevel, in this position. The resulting pressure drop for i
this geometry is less than that for a square-edged orifice or correctly installed beveled-edge orifice.
System Engineering performed a review to identify all systems with orifice configurations similar to those described above. The review also identified any Technical Specification requirements and the possible effects on meeting the requirements, should a bevel-edged orifice be installed backwards. Walkdowns were performed by System Engineering of all accessible orifices. Results of the walkdown, including those orifices which were not accessible, are documented in Air 373-201-94-0174901.
j System Engineering performed a review which identified all systems potentially impacted by a reversed orifice. Two systems, Reactor Building Equipment Drains and Reactor Building Floor Drains (RE, RF), were identified as having a potential for being in a non-conservative condition should the flow orifices be installed backwards, During a walkdown the 2RF004 orifice was identified as potentially installed backwards. This orifice plate was removed for inspection on August 19,1994 and verified installed backwards. Also, " inlet" indication stamped on the orifice tongue was verified to be on the correct side. Based on this fmding, the 1(2)RE003 and IRF004 orifices were determined to be installed correctly. The 2RF004 orifice was found to be in good condition and was re-installed correctly (i.e. beveled-edge downstream of flow, " inlet" indication facing upstream of flow)on August 19,1994. It was determined that the reversed orifice caused approximately 2% error in flow rate.
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i ATI'ACIIMENT (Continued)
RESPONSE TO NOTICE OF VIOLATION NRC INSPECTION REPORT 50-373/94017,50-374/94017 Details of this inspection are documented in PIF 374-201-94-01890 CORRECTIVE ACTIONS TO BE TAKEN TO AVOID FURTilER VIOLATIONS (373(374)/94017-01):
+ External visual inspections will be performed for all orifices with obstructed views or covered by insulation by the end of the LIRO7. refuel outage.
+ One orifice, believed to be installea c ckwards, will be chosen to be removed for inspection during L2R06/LlRO7.
+ Any RHR Service Water flow orifice observed to be installed backwards during these inspections, will be removed, inspected for condition, and re-installed in the correct position.
Any Fuel Pool Emergency Make-Up system orifice observed to be installed backwards during these inspections, will be removed and re-installed correctly. This action is prudent since the orifices are accessible and the work required to remove /rcinstall will be minimal.
+ Actions regarding RHR head spray and Reactor Water Cleanup return to FeedWater orifices will be determined after a visual inspection has been completed.
DATE WilEN FULL COMPLIANCE WILL BE ACIIIEVED (373(374)/94017-01):
. LaSalle County Station is in full compliance.
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