ML19256B571
| ML19256B571 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 07/26/1979 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Mary Johnson SOUTH CAROLINA ELECTRIC & GAS CO. |
| References | |
| NUDOCS 7908080743 | |
| Download: ML19256B571 (2) | |
Text
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UNIT ED ST ATES NUCLEAR REGULATORY COMMISSION 8
'A REGION 11 k(h"1'-c;Ihf[f 2
c 101 MARIE TT A ST, N W., SulTE 3100 ATL ANT A. GEORGIA 30303
'g In Reply Refer To:
RII:JP0 50-395 South Carolina Electric and Gas Company ATTN:
M. C. Johnson, Vice President Special Services and Purchasing P. O. Box 764 Columbia, South Carolina 29218 Gentlemen:
No The enclosed Bulletin 79-17 is forwarded to you for information.
written response is required.
However, the potential corrosion beha-vior of safety related systems as it regards your plant over the long term should be taken into consideration.
If you desire additional this office.
information concerning this matter, please contact Sincerely,
_. -Q?i James P. O'Reilly
,y Director
Enclosure:
IE Bulletin No. 79-17 7 9 0 8 0 8 0 74,y
JUL 2 81979 South Carolina Electric and Gas Company cc w/ encl:
T. B. Conners, Jr.
Conners, Moore and Corber N.W.
1747 Pennsylvania Avenue, Washington, D.C.
20006 A. A. Smith Quality Assurance Post Office Box 8 29065 Jenkinsville, South Carolina O. S. Bradham, Manager Nuclear Operations Post Office Box 6 29065 Jenkinsville, South Carolina
UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D. C.
20555 July 26, 1979 IE Bulletin No. 79-17 PIPE CRACKS IN STAGNANT BORATED WATER SYSTEMS AT P Description of Circumstances:
king incidents Durtng the period of November 1974 to February 1977 a number of crac steel piping systems and have been experienced in safety-related stainless stagnant or essentially stagnant port tons of systems which contain oxygenated, investigations revealed these cracks oc Metallurgical 304 material (schedule 10 borated water.
the weld heat affected zone of 8-inch to 10-inch typesurf ace and propagating in either an I.D.
Corrosion Cracking.
and 40), initiating on the piping transgranular mode typical of Stress chloride and oxygen contami-intergranular or corrodents to be indicated the probable Plants affected up to this time were Arkansas Analysis Nuclear Unit 1, R. E. Ginna, H.B. Robinson Unit 2, Crystal River Unit in the affected systems.
nation 76-06 (copy The NRC issued Circular Onofre Unit 1, and Surry Units 1 and 2.
f the problem.
attached) in view of the apparent generic nature o I which began in February During the ref ueling outage of Three Mile Island Unithrough-wall cracks at welds of this year, visual inspections disclosed five (5) t fuel cooling system piping and one (1) at a weld in the decay heat These cracks were found as a result of local boric in the spent removal system. confirmed by liquid penetrant tests.
(LER) dated May reported to the NRC in a Licensee Event Report up and later A preliminary metallurgical analysis was performed by the licensee of cracking was t fuel cooling system.
a section of cracked and leaking weld joint from the spen 16, 1979.
The conclusion of this analysis was that cracking was due to Intergran pipe I.D.
The cracking Stress Corrosion Cracking (IGSCC) originating on thetype 304 stainless steel is localized to the heat af fected zone where the sensittzed (precipitated carbides) during welding.
In addition to the main was several locations in the cracks were observed atfusion area where a miniscu through-wall crack, incipient weld heat atfected zone including the weld root The stresses responsible for cracking are believed lied lack of fusion had occurred.restdual welding stresses in as much as the calculated appis to be primarily There stresses were found to be less than code design limits.hemical species which promoted i
evidence at this time to identify those aggress ve cFurther analytical efforts in t thts IGSCC attack.
wells are being pursued.
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