ML19290B773
| ML19290B773 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 10/29/1979 |
| From: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | William Jones OMAHA PUBLIC POWER DISTRICT |
| References | |
| NUDOCS 7912140078 | |
| Download: ML19290B773 (1) | |
Text
M RAL FILES PDR:HQ UNITED $TATES LPDR
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October 29, 1979
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Docket No.
50-285 Omaha Public Power District ATTN:
W. C. Jones, Division Manager -
Production Operations 1623 Harney Street Omaha, Nebraska 68102 Gentlemen:
The enclosed IE Bulletin No. 79-17, Revision 1 is forwarded to you for action. A written response is required.
If you desire additional infor=ation regarding this matter, please contact this office.
Sincerely, C'
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Wh-l<(
24 i
'KarlV.Seyfritpj Director
- i
Enclosures:
1.
IE Bulletin No. 79-17, Revision 1 2.
List of IE Bulletins Issued in Last Six Months cc:
S. C. Stevens, Manager Fort Calhoun Station Post Office Box 98 Fort Calhoun, Nebraska 68102 1574 310 7913140
e UNITED STATES SSINS No.: 6820 NUCLEAR REGULATORY C0m!ISSION 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 STAGN' ANT B0 RATED WATER SYSTEMS AT PWR PLINTS 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 operating 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 e:: tension 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 numbcr 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 as a result of local boric acid buildup and later confirmed by liquid penetran cracking was reported to the NRC in a 1979. A preliminary metallurgical ana section of cracked and leaking weld jo DUPLICATE DOCUMENF5 7 4311 Entire document previously entered into system under:
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Y_ M./[ 7 R1 - Identifies those additions or rev ANO
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