ML19256E710
| ML19256E710 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 10/29/1979 |
| From: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Groce R Maine Yankee |
| References | |
| NUDOCS 7911150045 | |
| Download: ML19256E710 (1) | |
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Docket No. 50-309 OCT 2 9 gg79 Maine Yankee Atomic Power Company ATTN:
Mr. Robert H. Groce Licensing Engineer 20 Turnpike Road Westborough, Massachusetts 01581 Gentlemen:
The enclosed IE Bulletin 79-17, Revision 1 is forwarded to you for action.
A written response is required. If you desire additional information regarding this matter, please contact this office.
Sincerely, M
n kceH.Grier
- Director
Enclosures:
1.
IE Bulletin No. 79-17, Revision 1 w/ Attachment 2.
List of IE Bulletins Issued in the Last Six Months CONTACT:
L. E. Tripp 215-337-5282 cc w/encls:
E. Wood, Plant Superintendent E. W. Thurlow, President 1336 335 7911150 045
ENCLOSURE 1 UNITED STATES SSINS No.:
6820 NUCLEAR REGULATORY COMMISSION Accession No.:
0FFICE OF INSPECTION AND ENFORCEMENT 79082201STI 3 7 WASHINGTON, D.C.
20555 IE Bulletin No. 79-17 Revision 1 Date:
October 29, 1979 Page 1 of 5 PIPE CRACKS IN STAGNANT BORATED WATER SYSTEMS AT PWR PLANTS Dascription of Circumstances:
IE Bulletin No. 79-17, issued July 26, 1979, provided information on the R1 cracking experienced to date in safety-related stainless steel piping R1 systems at PWR plants.
Certain actions were required of all PWR R1 facilities with an operating license within a specified 90-day time R1 frame.
After several discussions with licensee owner group representatives and R1 inspection agencies it has been determined that the requirements of Item 2, R1 particularly the ultrasonic examination, may be impractical because of un-R1 availability of qualified personnel in certain cases to complete the in-R1 spections within the time specified by the Bulletin. To alleviate this R1 situation and allow licensees the resources of improved ultrasonic inspec-R1 tion capabilities, a time extension and clarifications to the bulletin have R1 been made.
These are referenced to the affected items of the original R1 bulletin.
During the period of Navember 1974 to February 1977 a number of cracking incidents have been experienced in safety-related stainless steel piping systems and por-tions of systems which contain oxygenated, stagnant or essentially stagnant bor-ated water.
Metallurgical investigations revealed these cracks occurred in the weld heat affected zone of 8-inch to 10-inch type 304 material (schedule 10 and 40), initiating on the piping I.D. surface and propagating in either an inter-granular or transgranular mode typical of Stress Corrosion Cracking.
Analysis indicated the probable corrodents to be chloride and oxygen contamination in the affected systems.
Plants affected up to this time were Arkansas Nuclear Unit 1, R. E. Ginna, H. B. Robinson Unit 2, Crystal River Unit 3, San Onotre Unit 1, and Surry Units 1 and 2.
The NRC issued Circular No. 76-06 (copy attached) in view of the apparent generic nature of the problem.
During the refueling outage of Three of this year, visual inspections disc in the spent fuel cooling system pipi removal system.
These cracks were fo DUPLICATE DOCUMENT and later confirmed by liquid penetra cracking was reported to the NRC in a Entire document previously 1979.
A preliminary metallurgical an entered into system under:
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ANO R1 - Identifies those additions or re No. of pages: