ML20069K708
| ML20069K708 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 04/20/1983 |
| From: | Maier J ROCHESTER GAS & ELECTRIC CORP. |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8304260456 | |
| Download: ML20069K708 (4) | |
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ROCHESTER GAS AND ELECTRIC CORPORATION
- 89 EAST AVENUE, ROCHESTER, N.Y.14649 N
.xmN E. MACR YE LE*H ON E vw. p,. -wns aat a coca na 546-2700 Ap ril 2 0, 1983 Director of Nuclear Regulation Attention:
Mr. Dennis M. C ru tchfield, Chief Operating Reactors Branch No. 5 U.S.
Nu clear Regulatory Commission Washington, D.C.
20555 Su bject :
Steam Generator Sleeving R.E.
Ginna Nuclear Power Plant Docket No. 50-244 De ar Mr. Cru tchfield:
By letter dated April 1, 1983 you approved u se of sleeves as an acceptable steam generator tube repair techniique at Ginna.
You r approval was documented in a Safety Evaluation based on ou r albmittal of a Sleeving Design Verification Report on August 31, 1982; and a Design.
Review Board Meeting on September 15-16, 1982.
The basic sleeve design described in these reports is a 26 to 36 inch long, bimetallic tube, emplosively welded at the lower end, and brazed at the upper end.
The length of a sleeve that can be installed in a given tube is restricted by the headroom available in the channel head.
Since the channel head is hemispherical in shape, this headroom becomes much smaller as you move towards the (g)[
periphery of the tu be bu ndle.
Consequ ently, it is not possible to use brazed sleeves in the ou ter rows.
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8304260456 830420 PDR ADOCK 05000244 G
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. In order to provide the capability for sleeving these tubes, we have developed a modification to the present sleeve design.
This_ modification, called a tubesheet sleeve (see attached drawing), is explosively welded at both the bottom and top.
The present tubesheet sleeve design is 22 inches long. However, we anticipate development of shorter. lengths in the fu tu re. The tubesheet sleeve is designed to rq) air tube defects which occur within the tubesheet.
The tubesheet sleeve is manu f actu red f rom the same 0.7 4 5 inch nominal O.D.,
- bimetallic tu bing as the sleeves.
The lower tubesheet sleeve to tube joint uses the same configu ration and explosive weld process as the brazed sleeves.
The upper tubesheet sleeve to tube joint also is made using an emplosive welding process.
The design of this weld is based on the design of the existing lower end joint which was described in ou r p revious submittals. This upper weld is made prior to making the lower end weld using a separate cartridge and detonation.
The weld is the same length (0.7 5 inches)- as the lower one, with its upper end a minimum of 1 inch below the top of the tu besheet.
The sleeve O.D.
is locally reduced over a length of 2 inches at the upper joint to provide the necessary weld standof f distance.
The I.D.
of the tube to be sleeved is cleaned by honing and dry swabing prior to installation of the tubesheet sleeve.
The weld configuration and installation procedure were developed using a series of tests.
Weld joints have been sectioned and
. evaluated by metallographic examination to confirm their adequ acy.
The final configu ration and welding procedure have been qualified to Section XI of the ASME Code in the same manner as the lower brazed sleeve joint. All qualification qpecimens achieved the mininum weld length of 0.7 5 inch.
We have reviewed the tubesheet sleeve design and in-stallation process against our " Steam Generator Rapid Sleeving Program Design Verification Rqport", dated August 1982.
It is aar determination that the tubesheet sleeve design and installation procedures are bounded by the analyses and tests described in that report.
Review of the tubesheet sleeve installation procedure as required by Technical Specification 6. 5 will be performed prior to installation. We request you r concurrence that the proposed tubesheet sleeves are an acceptable sleeve. repair technique in ~ accordance with ou r present Ginna Inservice Inspection (ISI) program.
We are planning to install approximately 50 of.these tubesheet sleeves du ring ou r present refu eling ou't ag e.
Ve ry t ru ly you rs,
i Jo n E. Maier l
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