ML20126K681
| ML20126K681 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 12/30/1992 |
| From: | Gates W OMAHA PUBLIC POWER DISTRICT |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20126K685 | List: |
| References | |
| LIC-92-342, NUDOCS 9301070227 | |
| Download: ML20126K681 (2) | |
Text
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Omaha Pub!!c Power District 444 South 16th Street Mall Omaha, Nebraska G8102-2247 402/636 2000 December 30, 1992 LIC-92 342 U. S. Nuclear Regulatory Commission ATIN:
Decument Control Desk Hail Station Pl-137 Washington, D. C.
20555
References:
1.
Docket No. 50-285 l
2.
Letter to NRC (A. C. Thadant) from GPPD (R. L. Andrews)
I dated August 28, 1986 (LIC 86-421)
Gentlemen:
SUBJECT:
Results of the 1992 Reactor Vessel Thermal Shield Inspection and Repair in accordance with commitments made in Reference 2 enclosed is Omaha Public Power District's (OPPD) final report on the thermal shield inspection and repair project that was conducted during the 1992 Refueling Outage.
In Reference 2, OPPD committed to conduct an ongoing monitoring program capable of detecting precursory evidence of thermal shield degradation and to inspect / repair the thermal shield when indications existed. With the submittal of the enclosed report, the actions specified in Reference 2 are complete.
In mid-1988, indications in the monitoring data showed that the thermal shield was exhibiting early signs of a loss of preload in some of the positioning
- pins, lherefore, the thermal shield support system was inspected and repaired during the 1992 Refueling Outage.
The conclusions of the final report are as follows:
1.
The internals vibration monitoring (datlon of the thermal shield IVM? system was successful in providing early warning of tre degra support system.
2.
The repair resulted in a coupled core support barrel (CSB) and thermal shield (TS) system.
3.
The natural frequencies of the repaired CSB and TS system do not differ from those associated with the system at original installetion.
4.
Post-repair IVM results support the fact that significant TS to CSB tightening was achieved, i
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3-t V. S. Nuclear Regulatory Commission LIC-92-342 Page 2 If you should have any questions, please contact me.
Sincerely, d&. 5 Y W. G. Gates 7
Vice President i
a WGG/sel Enclosure c:
LeBoeuf Lamb, Leiby and MacRae J.L.Mllboan,NRCRegionalAdministrator,RegionIV R. P. Mullikin, NRC Senior Resident inspector S. D. Bloom, NRC Project Manager I
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