ML19290B782
| ML19290B782 | |
| Person / Time | |
|---|---|
| Site: | Fort Saint Vrain  |
| Issue date: | 10/29/1979 |
| From: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | Millen C PUBLIC SERVICE CO. OF COLORADO |
| References | |
| NUDOCS 7912140094 | |
| Download: ML19290B782 (1) | |
Text
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e' October 29, 1979
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Docket No. 50-267 Public Service Company of Colorado ATTN:
Mr. C. K. Millen Senior Vice President P. O. Box 840 Denver, Colorado 80201 Gentlemen:
The enclosed IE Bulletin No. 79-17, Revision 1 is forwarded to you for information. No written response is required. However, the potential corrosion behavior of safety-related systems as it regards your plant over the long term should be taken into consideration.
If you desire additional information concerning this matter, please contact this office.
Sincerely, 1
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Karl V. Seyfrit Director
Enclosures:
1.
IE Bulletin No. 79-17, Revision 1 2.
List of IE Bulletins Issued in Last Six Months cc:
D. W. Warembourg, Nuclear Production Manager Fort St. Vrain Nuclear Station P. O.
Box 368 Platteville, Colorado 80651 L. Brey, Manager, Quality Assurance 1574 543 7912140
UNITED STATES SSINS No.: 6820 NUCLEAR REGULATORY COMMISSION Accession No.:
OFFICE OF INSPECTION AND ENFORCEMENT 7908220157 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 Description of Circumstances:
IE Bulletin No. 79-17, issued July 26, 1979, provided information on the cracking R1 experienced to date in safety-related stainless steel piping systems at PWR R1 plants.
Certain actions were required of all PWR facilities with an cperating R1 license within a specified 90-day time frame.
R1 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 R1 unavailability of qualified personnel in certain cases to complete the R1 inspections within the time specified by the Bulletin. To alleviate this R1 situation and allow licensees the resources of improved ultrasonic inspection R1 capabilities, a time extension and clarifications to the bulletin have been R1 made. These are referenced to the affected items of the original bulletin.
During the period of November 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 Onofre Unit 1, and Surry Units 1 and 2.
The NRC issued Circular No. 76-06 (copy enclosed) in view of the apparent generic nature of the problem.
During the refueling outage of Three Mile Island Unit I which began in February of this year, visual inspections disclosed five (5) through-wall cracks at welds in the spent fuel cooling system piping and one (1) at a weld in the decay heat removal system. These cracks were found
== a racult af lacal haric acid buil d"n and later confirmed by liquid penetran cracking was reported to the NRC in a I 1979. A preliminary metallurgical anal section of cracked and leaking weld joi DUPLICATE DOCUMENTj }/4 }4d Entire document previousl3 entered into system under:
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