ML19323C893
| ML19323C893 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 05/09/1980 |
| From: | Fay C WISCONSIN ELECTRIC POWER CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8005190383 | |
| Download: ML19323C893 (2) | |
Text
. _.
8005100 238(25 i
Wisconsin Electnc posta coursur 231 W. MICHIGAN. P.O. BOX 2046. MILWAUKEE. WI 53201 May 9, 1980 Mr. Harold R.
Denton, Director Office of Nuclear Reactor Regulation U. S. NUCLEAR REGULATORY COMMISSION Washington, D. C.
20555 Attention:
Mr. Robert A. Clarx, Chief Operating Reaccors Branch 3 Gentlemen:
DOCKET NO. 50-301 PRELIMINARY RESULTS INSPECTION OF TUBE R18C37 POINT BEACH NUCLEAR PLANT UNIT 2 As reported in our letter to you dated April 25, 1980, tube R18C37 was removed from the "A" steam generator during the current Point Ber.ch Nuclear Plant Unit 2 refueling outage.
This tube is presently being subjected to detailed metallurgical examination and evaluation.
We have received preliminary results regarding this examination which are summarized below.
The final report on this evaluation will be provided in four to six weeks.
To date, three samples have been taken from the R18C37 tube for examination.
A longitudinal sample was taken from an area from 3/4 inch above to 3/4 inch below the tubesheet intersection.
Metallographic examination of this sample in the as-polished condition showed no opening of grain boundaries associated with intergranular attack and no corrosion.
A transverse cross-section from a location approximately 16 inches below the top of the tubesheet showed a through-wall stress corrosion crack plus some associated intergranular attack.
Other areas around the circumference of this ring sample exhibited localized areas of intergranular attack ranging from 2 to 30 mils in depth.
Some of these areas of intergranular attack had stress corrosion cracks associated with them.
The tube I.D.
of this sample was free of any observable degradation.
A second ring sample was removed from the area ten inches below the top of the tubesheet.
This sample exhibited local areas of intergranular attack from 10 to 30 mils deep.
These areas of intergranular attack also had some associated stress corrosion cracking.
At least one additional sample from an area 4 inches below the top of tubesheet intersection will 00/
be made and examined.
5
/k Mr. Ilarold R.
Denton May 9, 1980 Chemical species found on the tube surface at a point 16 inches down from the top of the tubesheet by EDAX techniques showed the presence of: Na, Al, Si, P, Cl, S, and K.
The radiographs for the tube section passing through the tubesheet showed a cracklike indication running from 3 inches below to 18 inches below the top of the tubesheet.
Additional work will be done to document the tube condition and the results will be included in our final report.
Very truly yours,
- A C. W. Fay, Director Nuclear Power Department Copies to:
C. F. Riederer (PSCW)
Peter Anderson (WED)
Joan Estes (LSCFSE)
..