ML19290A443
| ML19290A443 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 06/04/1973 |
| From: | METROPOLITAN EDISON CO. |
| To: | |
| Shared Package | |
| ML19290A438 | List: |
| References | |
| NUDOCS 7911070625 | |
| Download: ML19290A443 (3) | |
Text
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THREE MIIZ ISIXTD NUCIZAR STATIC'I. UNIT NO.1 DOCKET NO. 50-289
_REULTS OF IN7ESTIGATICN CF SCRATCFES CN THE REACTOR VESSEL I;i"'EFliAI3 THEF;GL SHIELD A.
Description of Incident On May 11, 1973, the upper section of the Iower Core Support Assembly 4
(LCSA) shipping container was removed in preparation for assembly of 6
the TMI #1 Reactor Internals.
The LCSA shipping container was located in a vertical position at elev. 306 of the Reactor Building fuel transfer ennn1 Lifting of the shipping container upper section was accc=plished with the Reactor Building polar crane.
Although there was no indication of rubbing while the container section was being raised, as the top section of the LCSA was exposed, scratches were observed at eight (8) locations around the top outer surface of the ther=al shield.
The scratches varied in depth from.031" to.002" and in length from approxi-mately 2 " to lOh".
There were two areas in which the metal was raised
.010" and.030" respectively.
Transfers and reasurements of the affected areas were taken and recorded on May 15, 1973 A copy of this data is attached.
1557 303 49110 7 0 @f
Six (6) of the scratches were in locations opposite the shipping container cover screw pads; these pads had not been released prior to re= oval of the shipping container upper section.
Removal of the shipping container upper section was performed, in accordace with an approved construction procedure, NCP-103, and Eabcock & Wilcox Field Specification FS-III-le. Neither of these procedures identified a require-ment for backing off the six support pads prior to cover removal.
s The remaining two scratches were located opposite shipping container gusset plates on the W-Y axis. While it is obvious that the scratches resulted from the gussets rubbing the ther=al shield, it cannot be concluded that these scratches definitely occurred during shipping cover removal on 5/11+/73 The gussets are diametrically opposed.
During subsequent inspection of the ther=al shield outer surface, three add.1-tional areas of minor nicks and scratches were discovered.
These varied in depth from.015" to.002" and from approx 4 tely 3h" long te nicks of approxi-
=ately 1/16" and 3/16" in diameter.
These areas were located at 8" and 2'-o" above the flange of the lower section of the shipping container (see location sheet for radial position).
There is no evidence that these =inor scratches occurred during renoval of the shipping container section.
1557 304
B.
Analysis of Safety !=clications.
The scratches are considered minor and do not compromise in any degre the integrity or function of the ther=al shield, which is a lowly stressed cc=ponent in service.
C.
Corrective Action Repair of all scratch areas has been acco=plished in accordance with the following:
s 1.
Mechanically re=ove all raised metal above base (or parent surface) and loose metal ~cy conventional manual methods (band filing and stoning).
Power grinding shall not be allowed.
2.
Visually inspect using 5X =agnification.
Anyevidenceofraisedand/
or loose metal shall be cause for rejection and further rework.
3 Quality control to witness and document all repairs.
1557 305