ML19256B570
| ML19256B570 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 07/26/1979 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | John Miller GEORGIA POWER CO. |
| References | |
| NUDOCS 7908080741 | |
| Download: ML19256B570 (2) | |
Text
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t'p' "' %,'c UNITED STATES NUCLE AR REGULATORY COMMISSION 8 'kh'J'[ 1 5
REGION 11 2
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101 M AHlE TT A ST., N W, SUIT E 3100 AT L ANT A, GE oRGI A 30303 f'
,o JULLG B79 In Reply Refer To:
RII:JPO 50-321 50-366 Georgia Power Company ATTN:
J. 11. Miller, Jr.
Executive Vice President 270 Peachtree Street Atlanta, GA 30303 Gentlemen:
The enclosed Bulletin 79-17 is forwarded to you for action.
A written response is required.
If you desire additional information regarding this matter, please contact this office.
Sincerely,
.,'~~h 1 s, s JaaesP.O'Reilky t.
Director Enclosure :
IE Bulletin 79-17 Y90808074y
. Georgia Power Company cc w/ encl:
M. Manry, Plant Manager Post Office Box 442 Baxley, Georgia 31513 C. E. Belflower Site QA Supervisor Post Office Box 442 Baxley, Georgia 31513
UNITED STATES hTCLEAR REGCLATORY COT 11SS10N OFFICE OF INSPECTION AND ENTORCEMEN7 WASHINGTON, D. C.
20555 July 26, 1979 IE Bulletir. No. 7 'v PIPE CRACKS 15 ST AGNANT BORATED k ATER SYSTEMS AT PL1 ILA Description of Circumstances:
During the period of November 1974 to February 1977 a number of crackin safety-related stainless steel piping systems and or essentially stagnant experienced in have been systems which conta2n oxygenated, stagnant Metallurgical invest 2 rations revealed these cracks occurre d.:
porticns of h dmle H affected zone of E-2nch to 10-inch type 304 material (sc e berated water.
surface and propagating in either an the weld heat and 40), init iat ing on the piping 1.D.
intergranular or transgranular mode typical of Stress Corrosion Crack.nc.
chloride and oxygen contami-corrodents to be Analysis indicated the probable Plants affected up to this time were Arkansas Nuclear Unit 1, R. E. Ginna, H.B. Rob:nson Unit 2, Crystal River Unit 3, Sar.
nat2on 2n the affected systems.
The b1C issued Circular 76-Ot> (copy Onofre Unit 1, and Surry Units 1 and 2.
attached) in view of the apparent generic nature of the problem.
I which began in Februar.
refueling outage of Three Mile Island Unit (5) through-wall cracks at welds During the
'isual inspections disclosed five fuel cooling system piping and one (1) at a weld in the decay heat of this year, of local boric acid build-in the spent These cracks were found as a result This initial identification removal system.confirmed by liquid penetrant tests.
(LER) dated May up and later cracking was reported to the hTC in a Licensee Event Report A preliminary metallurgical analysis was performed by the licensee on of from the spent fuel cooling system.
i t,, 1979.; of cracked and leaking weld joint The conclusion of this analysis was that cricking was due to Intergranula a sectis I.D.
The cracking Stress Corrosion Cracking (IGSCC) originating on the pipe type 304 stainless steel is localized to the heat affected zone whece the during welding.
In addition to the main was sensitized (precipitated carbides) cracks were observed at several locations in the f usion area where a miniscule through-wall crack, incipient including the weld ro st The stresses res9onsible for cracking are believed weld beat affected zone l
d lack of fusion had occurred.primarily residual welding stresses in as mu There is no conclusive to be stresses were found to be lass than code design limits.
hich promoted evidence at this time to identif y those aggressive chemical spec this IGSCC attack.
welds are being pursued.
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