ML18347A524
| ML18347A524 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 03/26/1976 |
| From: | Bixel D Consumers Power Co |
| To: | Purple R Office of Nuclear Reactor Regulation |
| References | |
| Download: ML18347A524 (2) | |
Text
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consumers Power company Attached is a copy of a report entitled "Containment Building Tendon Surveil-lance,... Five-Year Surveillance Palisades Nuclear Plant," dated March 1976.
ThiS report prepared by our archi tect-e.ngineer describes the surveillance of the containment buildi.ng post tensioni.ng system.
The report has been overviewed by Consumers Power Company's Task Group.
In addition, site inspections were conducted both by the Task Group and Plant Staff personnel while the testi.ng was in progress.
As indicated in our previous letter concerning Containment Building Tendon Sur-veillance, dated April 29,' 1974, a study was conducted for determining the measurement technique that would be used for measuring the lift-off force in the five-year surveillance program.
From this study, the "All Shims Loose" method was developed and successfully incorporated into our surveillance pro-gram.
Every tendon that was tested (vertical, horizontal and dome) in 1975 had a measured lift-off force within the acceptance limits prescribed in the Techni.-
cal Specifications.
In addition, all these tendons were retensioned to within
- 3% of the li~-off force measured during detensioning, indicating that each tendon is sound and capable of sharing its design load.
As indicated in Appendix I,Section VI, of the report, a discontinuous wire was found protruding 3/4" from the end of the stressing washer in Tendon 59BD.
After reviewing this condition with the architect-engineer, it was conc:i_uded that the wire could have failed during the initial tensioning work and gone undetected; however, no reason could be found for the visual passover.
- Further, it is not believed that the wire moved since installation. This wire and four other discontinuous wires were examined to determine the cause of failure in accordance with our procedure TSF-2, even though they are not considered as surveillance wires. It was found that four wires had been initially damaged in the field.
The other wire in Tendon 59BD failed in tensile testing signi-ficantly below the minimum acceptance limit of 11.78 kips (for surveillance wires). It failed 5% below this value and was attributed to a manufacturing defect.
2.
The anchorage and sheathing filter inspection revealed some minor discrepan-cies, none of which were significant in nature nor would indicate degradation adversely affecting the post tensioning system.
Corrosion on the surface of surveillance wires was found to be insignificant and no more severe than found during earlier testing.
From the above, we conclude that the surveillance testing performed meets the requirements of the five-year tendon surveillance cycle as specified in Paragraph 4.5.4, Amendment No 14 (April 24, 1975) to Provisional Operating License No DPR-20, and that the "All Shims Loose" measuring technique will insure the repeatability of data for the next five-year test interval and thereafter.
w~f111 David A. Bixel Assistant Nuclear Licensing Administrator CC:
JGKeppler, USNRC