ML19290B803
| ML19290B803 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 10/29/1979 |
| From: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | Pilant J NEBRASKA PUBLIC POWER DISTRICT |
| References | |
| NUDOCS 7912140133 | |
| Download: ML19290B803 (1) | |
Text
CENTRAL FILES PDR:HQ UNITED STATES LEDR
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NUCLEAR REGULATORY COMMISSION TIC REGloN IV
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G11 RY AN PLAZA DRIVE, SUITE 1000 I i d o
ARLINGTON, TEXAS 76012 fj
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%' %,/* g October 29, 1979 Docket No.
50-298 Nebraska Public Power District ATTN:
J. M. Pilant, Director Licensing & Quality Assurance Post Office Box 499 Columbus, Nebraska 68601 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 systens as 1 regards your plant over the long term should be taken into coasideration.
If you desire additional information concerning this matter, please contac t this of fice.
Sincerely, s
Karl V. Seyfrit,-
Director
Enclosures:
1.
IE Bulletin No. 79-17, Revision 1 2.
List of IE Bulletins Issued in Last Six Months cc:
L. C. Lessor, Superintendent Cooper Nuclear Station Post Office Box 98 Brownville, Nebraska 68321 1577 296 7912140
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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 B0 RATED 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 facilitics 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 tifae 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 f
~
and later confirmed by liquid penetr.
cracking was reported to the NRC in 1979. A preliminary metallurgical a section of cracked and leaking weld j DUPLICATE DOCUMENT Entire document previously entered into system under:
R1 - Identifies those additions or r n.
No. of pages:
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