ML19256E882
| ML19256E882 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 10/29/1979 |
| From: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| References | |
| NUDOCS 7911150475 | |
| Download: ML19256E882 (1) | |
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1930 N. CALIFOHNIA BOULEVARD SUITE 202, WALNUT CREE K PLAZA WALNUT CREEK, CALIFORNIA 94596 October 29, 1979 Docket No. 50-312 Sacramento Municipal Utility District P. O. Box 15830 Sacranento, California 95813 Attention: Mr. John J. Mattimoe Assistant General Manager Gentlemen:
The enclosed Bulletin No. 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, hbT7~,cdE P,. H. Engelken Director
Enclosure:
IE Bulletin No. 79-17, Revision 1 cc w/ enclosure:
R. J. Rodriguez, SMUD L. G. Schwieger, SMUD 1339 051 7911150
VilITED STATES SSIf4S tio. :
6820 flVCLEAR REGULATORY C0F.MISSIOt4 Accession rio.:
0FFICE OF IiiSPECT1074 Ai10 Ef!FORCEMEtlT 790822013 WASHINGT0fi, D.C.
20555 October 29, 1979 IE Bulletin fio. 79-17 Revision 1 PIPE CRACKS Iti STAGriAl4T B0 RATED WATER SYSTEf4S AT PWR PLAtiTS Description of Circumstances:
IE Bulletin I?o. 79-17, issued July 25, 1979, provided information on the cracking R1 experienced to date in safety-related stainless steel piping systems at PWP, R1 plants.
Certain actions were required of all PWR facilities with an operating R1
, license within a specified 90-day time frame.
R1 After several discussions with licensee owner group representatives and inspection R1 agencies it has been determined that the requirements of Item 2, particularly R1 the ultrasonic examination, may be impractical because of unavailability of R1 qualified personnel in certain cases to complete the inspections within the time R1 specified by the Bulletin.
Tc alleviate this situation and allow licensees the R1 resources of improved ultrasonic inspection capabilities, a time extension and R1 clarifications to the bulletin have been made. These are referenced to the R1 affected items of the original bulletin.
R1 During the period of tiovember 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 fluclear 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 !!RC issued Circular tio. 76-06 (copy enclosed) in view of the apparent generic nature of the problem.
During the refueling outage of Three Mile Island "qit 1 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 as a result of local boric acid buildup and later confirmed by liquid penetrant tests. This initial identification of cracking was reported to the flRC in a Licensee Event Report (LER) dated May 16, 1979. A preliminary metallurgical analysis t section of cracked and leaking weld join DUPLICATE DOCUMENT
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'iA Entire document previously entered into system under:
ANO 1339 052
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