ML18059A867
| ML18059A867 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 03/06/1994 |
| From: | Rogers D CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML18059A868 | List: |
| References | |
| NUDOCS 9403140287 | |
| Download: ML18059A867 (2) | |
Text
consumers
- Power POWERINli MICHlliAN"S PROliRESS Palisades Nuclear Plant:
27780 Blue Star Memorial Highway, Covert, Ml 49043 March 6, 1994 Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 David W. Rogers Plant Safety and Licensing Director DOCKET 50-255 - LICENSE DPR PALISADES PLANT - CODE CASE N-504-1 USAGE APPROVAL FOR LEAK REPAIR OF CONTAINMENT SUMP CHECK VALVES On Thursday February 17, 1994 a leak was identified in a check valve located in the west engineered safeguards room.
The 24-inch austenitic stainless steel check valve, CK-ES3166, is located between the containment sump and the high pressure safety injection, low pressure safety injection, and containment spray pumps suction.
The leak was identified by a small accumulation of boron on the valve body.
The valve was declared inoperable and the plant entered the appropriate technical specification action statement and the reactor was shut down.
Non-destructive examination of check valve CK-ES3166 fevealed that, in.
addition to the through wall leak, various other indications exist at and near the leak location. Additional inspection of the same area on the second containment sump check valve, CK-ES3181, has revealed subsurface indications 1 that we have conservatively decided to repair.
Therefore~ both valves are scheduled to be repaired during this plant shutdown.
The ASME Code Case N-504, "Alternate Rules For Repair of Class 1, 2, and 3 Austenitic Stainless Steel Piping,Section XI, Division l" was approved on April 30, 1992 and revised (N-504-1) on August 9, 1993.
Due to *its recent approval, Code Case N-504-1 has not yet been approved for use in Regulatory Guide 1.147, "Inservice Inspection Code Case Acceptability, ASME Section XI Division l". However in accordance with footnote 6 to 10 CFR 50.55a, we
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request approval for the use of Code Case N-504-1 for the repair of the two
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Palisades. containment sump check valves.
Pursuant to 10 CFR 50.55a(a){3) and j.{< \\
based on the analysis contained in the attachments, we believe that Code Case I
N-504-1 provides an acceptable alternative repair to the repair techniques do.I>.
t I presently approved for use by the NRC.
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. A CMS' ENERGY COMPANY
Attached is documentation describing the particulars of the identified leak and our repair plans. Specifically, Attachment 1 is the Consumers Power Company root cause analysis for the leak identified on check valve CK-ES3166.
To supplement our root cause analysis, Sargent & Lundy Engineers was asked to perform an independent evidence review and root cause analysis which is contained in Attachment 2. contains a flaw stability calculation also completed by Sargent & Lundy Engineers. contains the Section XI Repair Plan which defines the methods and process controls for implementation of the Code Case weld overlay repairs. Attachment 5 contains the design calculations and drawings for the weld overlay repairs. Attachment 6 contains the procedure for application and examination of the weld overlay repairs.
Finally, Attachment 7 contains the results of a review completed to determine what affect the weld overlay process of Code Case N-504-1 would have on various types of defects,.if they were to exist, in the containment sump check valves.
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David W Rogers Plant Safety and Licensing Director CC: Administrator Region III, USNRC Resident Inspector, Palisades Attachments