ML19254D099
| ML19254D099 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 10/09/1979 |
| From: | Wachter L NORTHERN STATES POWER CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| NUDOCS 7910220375 | |
| Download: ML19254D099 (1) | |
Text
NSP NORTHERN STATES P
WER COMPANY MIN N E A PO LI S. M IN N E S OTA 5 5 401 0:tober 9,1979 Mr. James G. Keppler Director - Region III Office of Inspection and Enforcement United States Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137
Dear Mr. Keppler:
PRAIRIE ISLAND NUCLEAR GENERATING PLANT Dockets No. 50-282 and No. 50-306 Additional Response to IE Bulletin 79-17 As a result of recent information concerning the actual extent of inter-granular stress corrosion cracking (IGSCC) of 304 stainless steel piping at Three Mile Island Unit (TMI-1), we request an extension be granted for our Prairie Island Nus. ear Generating Plant for the implementation of Item 2 of IE Bulletin 79-17, " Pipe Cracks in Stagnant Borated Water Systems at PWR Plants."
As was originally reported, out of the 1902 welds inspected at TMI-1, there were 350 welds that had IGSCC indications.
Since then, it has been reported that these 350 welds were reevaluated with an examination technique that could discriminate between actual IGSCC and geometrical reflectors, and only 32 of the 1902 welds were found to have IGSCC indications.
In view of the changing IGSCC data base at TMI-l and the actual systems that are involved, we request a 90-day de'
'n the implementation of Item 2.
This extension will provide us the time to evaluate the data from TMI-1, develop a sound inspection plan waich assures the optimization of the inspection techniques, and implement the inspection program with reasonable confidence in its effectiveness and with the necessary skilled inspection personnel.
Yours very truly, L. J. Wachter Vice President - Power Production and System Operation ec:
Mr. G. Charnoff OCT 111979 2
351 3Y 7910220