ML20094H144
| ML20094H144 | |
| Person / Time | |
|---|---|
| Site: | Braidwood  |
| Issue date: | 02/27/1992 |
| From: | Kovach T COMMONWEALTH EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9203090068 | |
| Download: ML20094H144 (3) | |
Text
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Commonwealth Edison 1400 Opus Place v
Downers Grove, Illinois 60515 f
February 27, 1992 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Hashington, DC 20555
Subject:
Braidwood Nuclear Power Station Units 1 and 2 Response to Notice of Violation inspection Report Nos. 50-456/91023:50-457/91021 NRC Docket Numbers 50-456 and 50-457
Reference:
H. Miller letter to C. Reed dated January 31,1992 transmitting NRC Inspection Report 50-456/91023:50 457/91021 Enclosed is Commonwealth Edison Company's (CECO) response to the Notice of Violation (NOV) which was transmitted with the reference letter and Inspection Report.
The NOV cited one Severity Level IV violation requiring a written response.
The violation concetned the failure to tarminate a Type A leak rate test when excessive leakage paths were identified.
CECO's response is provided in the following attachment.
If your staff has any questions or comments concerning this letter, please refer them to Denise Saccomando, Compliance Engineer at (708) 515-7285.
Very truly your, h $ k.trud f T.J. Kovach Nuclear Licensing Manager Attachment cc:
A. Bert Davis, NRC Regional Administrator - RIII R. Pulsifer, Project Manager - NRR S. Dupont, Senior Resident Inspector-Braidwood f,)l
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ATTACllMENT A RIISPONS!! TO NOTICE OF VIOLATION NRC INSPECTION Rl! PORT 50 456/91023;457/9102I YlOLATION 10 CFR Part 50, Appendix J, Section Ill.A.I.a requires, in part, that if during a Type A test potentially excessive leakage paths are identified wluch will interfere with satisf actory completion of the test, the Type A test shall be tenninated and the leakage tinough such paths shall be measured using local leakage testing methods. The conective action taken and the change in leakage rate detennined from the tests and the overall integrated leakage detennined from the local leak ami Type A tests shall be included in the report subndtted to the Conunission.
Contrary to the above, on February 12 through 14,1991, during perfonnance of the Unit i Type A test, potentially excessive leakage paths were identified which interfered with satisfactory completion of the test, and the Type A test was not tenninated nor was the leakage through such paths measuied.
REASOMEORTilEXIOLAT10N On February 11,1991, Draidwood Station initiated a Type A leak rate test for Unit
- 1. On February 12, the temperature stabilization period began. Approximately four hours later, it was decided to continue the stabilization period due to a computer calculation showing a high containment leakage rate. Personnel were dispatchd to identify the source or sources, of the calculated leakage. Six possible leaks were identified, but the magnitude of these leaks could not be quantified; therefore, their significance couki not be detennined.
Test personnel proceeded to isolate these potential paths. Additionally, in some instances, continuous make up air was applied to facilitate the continuance of the test. The NRC was
-infonned prior to pressurization between the valves. Concurrently, airlock shaft sealleakage was identified and blocked. The test engineers continued to collect and analyze the data until the previously observed leakage rate had decreased. Stabilization was verified and the acceptance criteria was met. On February 13, the statistical integrated leak rate test was initiated. Within twenty-four hours, the statistical test was detennined successfully completed. An induced leak rate test was performed to verify the statistical test residts.
The test engineers proceeded under the assumption that they had performed a successful as found test. They were not aware of the concent that sufficient time was not allowed to quantify excessive leakage for specific paths. Additionally, Draidwood Technical Staff Surveillance, IBwVS 6.1.2.a-l," Unit i Primary Containment Type A Integrated Leakage Rate Test (ILRT)," did not address this specific issue.
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-CORRECTIVE. STEPS _TAKEN AND RESULTS AClllEVED l
Subsequent to the Unit 1 Type A test, station personnel took their experience and lessons leamed from the Unit I test and applied them to the Unit 2 Type A test, These actions contributed significantly to the successful perfonnance of the Unit 2 test. The systematic, methodical process used to identify, quantify, and isolate steam generator leakage chuing peifonnance of the Unit 2 test was considered to be a sttength by the NRC inspector in the referenced inspection ieport. Prios to execution of the Unit 2 Type A test in September,1991, the Unit 2 Type A test procedure,2ilwVS 6.1.2.a-l, was revised to include an appendix on excesHve leak detection and an appendix to record infonnation regarding penetrations that had not been propetly challenged. Furthermore, training was 1rovided for the pensonnel conducting the Unit 2 test. This training emphasi7ed potentia leak paths, the importance of a sequence of events log and reviewed the entue test evolutio.t Additionally, station management provided written instructions to the ILRT Test Directors stating management's expectations for the Sequence of Events Log entries.
CORRECrlVILSTEPS.TAKEN_TOAVOID FURTilERNIOLATION Braidwood Technical Staff Surveillance 1HwVS 6.1.2.a-1 will be revised to incorporate the pmcedure enhancements which were incorporated into 2HwVS 6.1.2.a-1 and pmved effective during the perfonnance of the Unit 2 Type A test.
Additionally, Braidwood Technical Staff Surveillances 1(2)llwVS 6.1.2.a-1," Unit 1(2) Primary Contairunent Type A Integnited Leakage Rate Test (ILRT)," will be revised to include monitoring of plant response time between isolation of individual containment penetrations as well as guidance for identifying any change in leakage rates as a tesult of isolating these penetrations, lloth piocedutes will be revised to require Sequence of Hvents Log entries to document activities associated with excessive leak rate quantification. Finally, a caution statement will be added to restrict the use of continuous make up air to facilitate the continuance of the test.
I The procedure revisions are egrcted to tw completed prior to the next Unit i Type A test which is currently scheduled for March,1994.
DKl'lLWH ER EUILCOMP11 ANCE_W.lLL Dli AClllliVED 4
Full compliance was achieved with the implementation of the conective actions prior to the Unit 2 ieak rate test.
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