IR 05000352/1987023
| ML20235L540 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 09/21/1987 |
| From: | Anderson C, Chung J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML20235L473 | List: |
| References | |
| 50-352-87-23, NUDOCS 8710050507 | |
| Download: ML20235L540 (12) | |
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U.S. NUCLEAR REGULATORY COMMISSION
REGION I
Report No.
50-352/87-23 Docket No.
50-352 License No.
Licensee: _ Philadelphia Electric Company 2301 Market Street Philadelphia, PA 19101 Facility Name:
Limerick Generating Station, Unit 1 Inspection At:
_ Limerick, PA Inspection Conducted: August 8-13, 1987
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Inspectors:
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4 ~ M eactor $ngineer
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date ung,
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A preved-by:
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J. Anderson, Chief, Plant Systems dat Section, DRS In_sgection Summary:
Inspection on August 8-13, 1987 (Inspection Report No. 50-352/87-23)
Areas Inspected:
Routine unannounced inspection of procedure review, test witnessing and preliminary results evaluation of periodic containment integrated leak rate test.
Results:
No violations or deviations were identified.
8710050507 870924 PDR ADDCK 05000352 G
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DETAILS 1.0 Persons Contacted M. Decker, CILRT Test Director S. DiMauro, QA Lead Monitor
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- J. Doering, Superintendent - Operations
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- C. Endries, Administrative Engineer
- J. F. Franz, Jr. Station Manager, LGS M. Gordon, Technical Assistant i
R. F. Hennessey, QC Site Supervisor-l S. Lewis, CILRT Test Director l
- J. Muntz, Engineer j
- D. Poliero, Performance Engineer General Physics
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R. Carey, Engineer USNRC S. Kurchaski, Resident Inspector The inspector held discussions with other licensee employees during the inspection, including operations, technical supports, health physics, and other craft personnel.
- Denotes those present at the exit meeting held August 13, 1987.
2.0 Administrative Controls of Containment Integrated Leak Rate Test (CILRT)
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Several pretest meetings were held with licensee representatives to
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discuss the progress of test preparations, the scope of the test, and the
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testing methodology.
The inspector interviewed selected licensee personnel for their qualifications and adequacy of training, and reviewed administrative documents, procedural sign-offs, data collection and the official Type A test-log of events.
The test activities were observed to verify that:
prerequisites were met; the test was conducted in accordance with the procedures and applicable requirements; test directors were designated and their responsibilities were defined; and required plant parameters were being recorded.
The following observations were made prior to and during the performance of the test:
Containment Integrated Leak Rate Test (CILRT) valve lineups were in
progress and ILRT tags were being posted for the valves and equipment associated with the tes j
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l The scope and details of the CILRT were discussed with the test
personnel.
Maintenance activities were adequately conducted to support the test.
- The licensee secured the Drywell air circulating fans during the
test to provide a more stable containment atmosphere.
Three air compressors were aligned for the CILRT including one I
standby compressor.
The CILRT test directors were designated and their responsibilities
were clearly defined in the test procedure.
An access listing was developed to control containment access during
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Test personnel training and their qualifications were adequate.
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The following documents were reviewed:
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Control Room Log book.
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Calibration records of sensors and instrumentations associated with
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the CILRT.
c.
Limerick Unit 1 Technical Specifications and FSAR.
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Selected containment Penetration Valve Lineup Diagrams.
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Sensor location diagrams.
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f.
Surveillance Procedure, ST-1-060-490-1, Integrated Leak Rate Test (ILRT), Revision 1, August 5, 1987.
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Limerick Generation station, Functional Organization Chart.
h.
Temporary Procedure Change (TPC) #87-1054, ST-1-LLR-092-1, Revision 2.
August 2, 1987.
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TPC #87-092f., ST-1-LLR-092-1, July 22, 1987.
j, 10 CFR Part 50, Appendix J. Primary Reactor Containment Leakage
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Testing for Water Cooled Power Reactors.
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Bechtel Nuclear Topical Report, BN-TOP-1, Revision 1, Testing Criteria for Integrated Leakage Rate Testing of Primary Containment Structures for Nuclear Power Plants.
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USNRC IE Information Notice No. 85-71, Containment Integrated Leak Rate Tests.
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Findings i
In accordance with the ILRT test procedure, system components and contain-ment isolation valves were identified by ILRT tags.
These tags would-assure that the equipments would not be operated without special permis-sion test director or their status would not be altered during the testing. The inspector observed that there were-more than.2,600 tags i
issued for the ILRT.
Several tags were issued more than once, during the
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tagging process. The inspector also observed that the reactor building access list, during the ILRT performance included numerous station person-nel, regardless of their involvements or participation in the testing activities.
In response to the above observations by the NRC inspector a licensee representative stated that the test procedure had not been updated since l
the preoperational testing phase and the process would be evaluated to minimize the number of tags in a future revision of the procedure.
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l 3.0 Pre-Test Activities 3.1 Failure of "As Found" CILRT On May 20, 1987, the licensee determined that the Local Leak Rate Test (LLRT) results of the Main Steam Isolation Valves (MSIV) exceeded the Technical Specifications (TS) 3.6.1.2, b, and c limits for the total primary containment penetration leakage (0.6La,) and TS 3.6.1.2.a limit for the Integrated Leakage Rate (0.75a). Where, La is 0.5
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weight % per day.
In terms of Leakage flow Rates, 0.6La and 0.75La l
are equivalent to 94,964 Standard Cubic Centimeter per Minute (SCCM)
and 118,705 SCCM respectively.
In addition, the results of Drywell purge exhaust LLRT indicated that the "As Found" leakage rate exceeded 94,964 SCCM (0.6La). The above
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findings were documented in LER No. 87-18.
i As a result of the above, the running LLRT total, of "As Found" penetration leakage rate as of May, 1987, was 129,548.28 SCCM. This leakage exceeded the Type "A" test acceptance criteria of 0.75La l
(118,705 SCCM).
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Subsequently, the licensee declared that the "As Found" Type "A" test was a failure.
In accordance with the requirement specified in paragraph III.A.6(a) of 10 CFR 50, Appendix J, the above failure l
requires the licensee to submit a schedule of the next Type "A" test i
for commission approval.
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3.2 Walkdown Inspection Several general plant tours were made between August 8 and August 12, 1987. A pre-closecut containment inspection was also conducted at 9:05 a.m., on August 9, 1987.
The objectives of these tours were for the inspector to become familiar with the plant equipment and sys-tems, and to verify the location and status of the various plant equipment and instrumentation for the Integrated Leak Rate Test (ILRT).
General housekeeping and equipment tagging were inspected prior to containment pressurization.
It was noted that a series of Chiller-Dryers were lined up with three compressors (2 for operations; 1 for backup) to maintain a low moisture content during containment pressurization.
The positions of selected Dewpoint sensors and RTDs inside the Drywell were inspected for adequacy and consistency with the test procedure.
The containment pressure and the leakage data were monitored in the data center using two pressure sensor / instruments and a computer with a display system, respectively.
No unacceptable conditions were identified.
3.3 Procedure Review The inspector verified by a review of the test procedure that a Type
"A", 8-hour ILRT test would be conducted employing the Total Time methodology described in Bechtel-Topical Report, BN-TOP-1, Revision 1.
The instrument verification test would be conducted in accordance with the mass point methodology described in ANSI _N56.8-1981.
Both BN-TOP-1 and ANSI N56.8-1981 are endorsed in Technical-Specifications 4.6.1.2.b and c.
The computer software for calculating containment leakage was provided i
by the General Physics Corporation.
The inspector verified the
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algorithm of the software by conducting independent calculations of selected data points.
The inspector noted that the system lineups ind valve isolations were often inconsistent with the test procedure, and temporary changes were made extensively.
The inspector further noted that the licensee was using the preoperational CILRT procedure, which had to be changed extensively in order to perform the periodic, normal outage "As left" test.
The licensee stated that the temporary changes would be incorporated into the next revision.
A total of 17 RTDs and 9 Dewcells were installed to monitor the containment air mass during the ILRT.
The calculational details were clearly described in he procedure.
No deficient conditions were identified except the concern'related to tagging.
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4.0 Containment Integrated Leak Rate Test (CILRT)
During the period August 8 through August 14, 1987, a periodic containment integrated leak rate test was performed.
The test was performed in accordance with the requirements specified in Technical Specifications, BN-TOP-1, and Appendix J, 10 CFR 50., and the test results met the acceptance criteria for the "As Left" Type "A" test.
4.1 Test Instrumentation l
The inspector eviewed the cdibration records for the ILRT instrumentation to ascertain that the instruments were within proper calibration tolerance for the test. These records indicated that the standards used were traceable to the National Bureau of Standards (NBS).
The inspector observed the operation of the automatic data collection system during the conduct of the test.
The following calibration records and documents were reviewed.
j Limerick Generating Station, Sensor Failure Analysis,
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GP-R-312001, June 29, 1987.
Certificate of Calibration, Volumetrics, Dewpoint Sensors,
ME-264447, May 24-27, 1987.
Certificate of Calibration, Volumetrics, Platinum RTD l
Sensors, ME-264447, May 24-27, 1987.
Certificate of Calibration, Volumetrics, precision pressure
l gauge, July 20, 1987.
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Certificate of Calibration, Volumetrics, Flowmeter,
March 19, 1987.
A comparison of the sensors used for the test against BN-TOP-1 recommendations is listed below:
1 BN-TOP-1 Recommended Recommended Sensor Minimum Actual RTD
17 (11 DW; 6 suppression pool)
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Dewpoint Temperature
9 (6 DW: 3 l
suppression pool)
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Pressure
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Fl owmeter
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The total sensors used met the latest industry standards, and ANSI l
N56.8-1981, which specify a minimum of three Dewpoint sensors.
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ANSI standard also specifies that no Drybulb temperature sensor be allowed to represent a volume fraction of the containment greater than 10% during the C::LRT.
l 4.2 Stabilization Period The stabilization per od commenced at 12:00, August 11, 1987 and l
completed by 18:25 hour, August 11, 1987.
The stabilization period lasted for 4-hours, w th the following results:
Test Duration - 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />
Acceptance Criteria: 1). The rate of change of average temperature is less than 1*F/hr averaged over the last 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />.
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2). The rate of change of temperature changes less than 0.5 F/hr/hr averaged over the last 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />.
Actual data for the stabilization period is; l
l Acceptance Criteria Actual Data
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Criterior 1:
1.0 0.2537 ( F/hr)
Criterion 2:
0.5 0.2630 ( F/hr/hr)
4.3 Integrated Leak Rate Test (ILRT) Results Prior to actual data taking, the ILRT engineer performed a "long-hand" calculation of te st parameters, instrument parameters, and selected l
data points to verify the computer software calculations.
During the 10# leak chases, several leaks were identified and some of those leaks were quantified prior to isolation or repairs.
The identified leaks included; I
Vent valves 1023 and 1024 with an estimated leak of 8 gpm
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Vent valves 1028 and 1027 with an estimated leak of I gpm
Vent valves 1025 and 1026 with an estimated leak of 8 gpm
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Valve IF054 with 3 gpm leak
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HCU with 26.4 gpm leak
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Temporary procedure change, TPC #11, was issued to isolate the above leaks, and appropriate corrective measures were taken.
In addition, the following leak sources were identified and corrective measures were taken:
Leaks Type and Nature of the Leaks Air Leaks RV40-105 packing leak (Tighten the root valve)
HV51-1F016B audible noise
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HV51-1F021B audible noise HV44-1F039 RWCS solenoid valve leak HV57-114 severe stem leak (repaired at 14:40,8/12/87)
HV57-161 small packing leak HV57-162 severe stem leak at 14:30, 8/12/87 HV57-124 moderate packing leak HV57-131 small packing leak HV57-104 severe packing leak at 17:50, 8/12/87 HV57-123 severe stem leak at 17:45, 8/12/87 HV57-163 severe stem leak at 14:45, 8/12/87 Water Leaks
HV-1F015A moderate packaging leak
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HV52-1F13B HV52-1019B HV51-1055 minor leak PSV51-134B 0.5 gpm leak A special ILRT status meeting was held by the licensee management at 0830, on August 12, 1987 to resolve technical and management issues associated with the ILRT performance and leaks.
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meeting, a special task team was appointed to identify and verify the leak sources, and to take appropriate actions including:
l Generation of Temporary Change Forms (TCF)
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Generation of Maintenance Request Form (MRF) to tighten the
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LLRT and Stroke time testing after repairs.
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Snoop test and de-energization of the leakers
- Other operational details associated with the valve isolation
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and testing.
j The inspector was informed that the isolated penetrations would be local-leak-tested, and appropriate penalties would be added to the ILRT results. A preliminary estimation by the inspector indicated
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that the penalties would be less than 0.2w'4/ day.
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The official ILRT was commenced at 05:00 am., August 13, 1987, for a period of 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />, and completed at 13:15 am.
The test specifications
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and results are as following:
Containment Design Leakage Rate, La:
0.50 weight "s/ day ILRT Acceptance Criteria, 0.75La:
0.375 #4/ day Fitted Total Time Leak Rate:
0.1164 V4/ day Upper 95*4 Confidence Limit:
0.1619 V4/ day Mass Point Upper 9574 Confidence Limit:
0.1309 V4/ day l
Based on the above results, the "As Left" ILRT results appeared to meet the requirements specified in Appendix U. 10 CFR 50. A final evaluation will be performed on receipt of the final report by the licensee.
The test data points were plotted as shown in the attachment.
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The initial data perturbations in the figure represent artificial l
effects created by the statistical methods employed.
It does not represent the true condition.
4.4 ILRT Chronology i
August 9, 1987 0905 Pre-Closecut Drywell inspection August 10, 1987 1006 - 1630 General plant tours:
Drywell venting, air compressors, penetration inspections.
1715 Drywell hatch airlock closed.
1830 Commensed pressurizatio *
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August 11, 1987 0030 Secured Compressor for 10 psig walk-down inspection 0240 re-started compressor.
0820 Containment pressure 37.5 psi with pressurization rate of 5 #/ hour.
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1030 Secured compressor:
attained test pressure of 44 psig.
Leak chases commenced.
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1200 - 1825 Stabilization period completed.
August 12, 1987 l
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0830 ILRT status meeting:
identified leak sources; a
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special task team formed to resolve problems.
August 13, 1987 j
0243 Isolated known leakers; reduced the leakage significantly.
0500 Official "As Left" ILRT commenced.
0615 Main condenser vacuum broken accidentally.
1325 Completed ILRT (included bad data points during the broken vacuum period).
5.0 QA/QC Test Coverage The inspector discussed QA/2C coverage during the ILRT and observed QA
monitoring of the test, procedure evaluations, and audit coverage.
It was i
determined that QA surveillance activities were adequate as observed in the following:
J QA auditor check list, audit No. AL87-90ST, for LLRT was adequate.
- Test procedure reviews and findings.
- During routine leak chase activities, the inspector noted that some ILRT l
tagging activities were performed by QC engineers, wearing distinctive
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white QC hats.. Subsequent discussion with a QC supervisor clarified the
confusion by a review of an internal memorandum and the inspector verified, in that several QC personnel were temporarily detailed to the ILRT activities and these personnel would not participate in the ILRT monitoring activities.
No unacceptable conditions were identified.
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l 6.0 Local Leak Rate Test (LLRT)
When a certain containment isolation valve was tested for a Type "C" LLRT,
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a simulated accident pressure was applied in the reverse direction. This was because a test line was not provided to the penetration to allow a pressurization of the line in a normal manner.
Reverse direction LLRT may be conservative for valve seat leakage.
However, the valve packing might not be subjected to the pressure and leak test.
The licensee agreed that valve packing for some containment isolation
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valves may be in this category.
They stated that all LLRT valves tested i
in a reverse direction would be evaluated and corrective measure would be taken.
This is an unresolved item, pending licensee evaluation of valve reverse direction testing.
(50-352/87-23-01).
7.0 Plant Tours The inspector made several tours of the plant facilities, including the control room, reactor building, inside of Drywell, penetration area, and plant exterior (compressors).
The objectives and findings of the tours includes;
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The containment interior was clean and general housekeeping was good.
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General housekeeping in the exterior of the Drywell in the reactor
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building was acceptable.
Many ILRT tags were issued.
Personnel access list to the
reactor building during the ILRT included excessive personnel.
i The administrative controls for operations during the ILRT test l
needed improvement. As an example, the main condenser vacuum was broken during the ILRT, and this particular operation was not discussed with the test director.
However, this was an isolated
case.
No other deficiencies were identified.
8.0 Exit Meeting Licensee management was informed of the purpose and scope of the inspection at the entrance interview. The findings of the inspection were periodically discussed and were summarized at the exit meeting on August 13, 1987.
Attendees at the exit meeting are listed in section 1.0.
At no time during the inspection was written material provided to the licensee by the inspector.
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