ML20040A394
| ML20040A394 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 08/27/1980 |
| From: | Dodd C OAK RIDGE NATIONAL LABORATORY |
| To: | Mcclung R OAK RIDGE NATIONAL LABORATORY |
| Shared Package | |
| ML17250A806 | List: |
| References | |
| FOIA-81-313 NUDOCS 8201210014 | |
| Download: ML20040A394 (4) | |
Text
i : t,( : ';o.,. x l-lo t s INTRA LABORATORY CORRESPONDENCE OAK HIDGt t:ATIOt4 AL L ADOR ATORY August 27, 1980 To:
R. W. McClung From:
C. V. Dodd C.V. Dol /
Subject:
Trip to Washington, D.C., to Review San Onof re Plans on August 15 I traveled to Washington, D.C.,
at the request of NRC to review the plans of Southern California Edison and Westinghouse for returning the San onofre Nuclear Plant to power.
The inspection of all three steam generators had just been completed and, due to the large number of indications in the central region of the hot leg of the steam generators, a sleeving program for tubes was initiated.
In addition, pressure tests had been perf ormed on a number of tubes in steam generators A and C, and a total of 14 tubes had been pulled and examined metallographically. The utility and Westinghouse had outlined a very ambitious program to install and inspect the sleeves between now and November 1, 1980.
The steam generators will be decontaminated, which should reduce the radiation Icvels at the tubesheet from 35 to about 5 R/h, and allow longer exposures for skilled personnel.
Tubes that need plugging and cannot be sleeved, using the present technique will be plugged with removable plugs.
The sludge layer in the San Onofre steau generators is a hard material and seems to lend some strength to the' tubes in burst tests.
Tests on pulled tubes showed the tubes with corrosion 75% through the wall could still withstand pressures over 3000 psi.
An improved chemistry program was initiated to reduce the corrosion.
An analysis of the design of the sleeve was given, along with ideas on how to inspection the sleeve and a determination of the affected area of the steam generators was l
presented.
B. D. Liaw of NRC requested that I review Westinghouse's planned NDE program and the determination of the affected area that will be sleeved.
NDE of. Sleeved Steam Cencrator Tubes There will be many problems in the inspection of the sleeved tubes, including:
1.
The reduction in inside diameter due to the sleeve may cause a reduction in the diameter of the eddy-current probe used for in-service inspection, which in turn will cause a reduction in inspection sensi-tivity.
If the loss of sensitivity is excessive, it nay be avoided I
by inspecting nost of the tube from the cold leg with a larger coil or by using a nultiple-array coil that expands to fit the tube.
There
- 1 will be problems with both techniques and may require development.
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