ML19318C449

Forwards Info in Response to 800613 Ltr Re Reactor Vessel Nozzle Underclad Cracking.Ultrasonic Exams Not Presently Needed.Cladding Destructive Exam Recommended

ML19318C449
Person / Time
Site:	Farley
Issue date:	06/25/1980
From:	Clayton F ALABAMA POWER CO.
To:	Schwencer A Office of Nuclear Reactor Regulation
References
NUDOCS 8007010489
Download: ML19318C449 (4)

Text

Alabama Power Company 600 North 18th Street Post Office Box 2641 Birmingham, Alabama 35291 Telephone 205 323-5341 h k hbo?CR,%" int Alabama Power the southem erectnc system June 25, 1980 Docket No. 50-364 Director of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D. C. 20555 Attention: Mr. A. Schwencer JOSEPH M. FARLEY NUCLEAR PLANT-UNIT 2 REACTOR VESSEL N0ZZLE UNDERCLAD CRACKING Gentlemen:

The NRC letter of June 13, 1980 regarding the subject issue requested fabrication information associated with the Farley Unit 2 reactor vessel nozzles. The requested information is provided in the enclosure.

It is our understanding that following a review of this infor-ration, the NRC will identify those reactor vessels that will require an augmented ultrasonic examination of the nozzles. It is our position that such examinations are not needed until a sound technical basis is established for the examinations. The cladding process / heat treat-ment used to fabricate the Farley 2 reactor vessel nozzles is such that it does not induce underclad cracking. Ultrasonic examinations of the nozzles could result in indications of the same nature as Salem Unit 2 (cold shuts, i.e., lack of fusion within the cladding). These indications are thought to be cladding defects; however, without destructive examination this cannot be conclusively demonstrated. ,

Therefore, inspections will only serve the purpose of providing statistical data. Our recommendation would be to inspect nozzles ,

currently in the shop and, if required, conduct destructive examination of the cladding to obtain a positive correlation between the indications and cladding process / heat treatment which would then be used as the technical basis to resolve this issue.

Based on the above, we do not propose to conduct the augmented ultrasonic examinations of the reactor vessel nozzles on Farley Unit 2.

Should these inspections be required by the NRC, schedule delays in meeting the September 1, 1980 fuel load date are anticipated, fDOl S

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U. S. ' Nuclear Regulatory Conunission ~

Attention: .Mr. A. Schwe'ncer

. ~ June 25, 1980 '

'Page~2 Should you have any questions, please advise.

Yours very truly, je.,

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F. L. Clayton,'Jr.

l RWS:de j Enclosure cc: Mr. R.;A. Thomas Mr. C. F. Trowbridge i

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EfCLOSURE NRC REQUEST FOR IrlFORMATION ON THE FARLEY Ui!IT 2 REACTOR VESSEL f0ZZLES The information provided below is applicable to all noz:les on the Farley

__ Unit 2 reactor vessel.

(1) Nozzle base metal material specification type and grade:

ASTM A508 C.l.2 (2) Clad process type, electrode size and number of clad layers:

Nozzle Bore; submerged arc welding process with oscillation, single -

3/32 inch diameter electrodes, at least 2 clad layers.

Nozzle Radii and Prolongations; shield metal arc welding process, either 2 or 3 clad layers.

1st Clad Layer: either 1/8 inch or 5/32 inch diameter electrodes.

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2nd and 3rd Clad Layer: either-1/8 inch, 5/32 inch or 3/16 inch diameter electrodes. ,,

(3) Heat input (amps, volts, speed) for each clad layer Nozzle Bore; Amps Volts Speed (IPM) 1st clad layer 310-340 42-43 6 Remaining layers 340-360 42-43 6 Nozzle Raddi and Prolongations;

} 1/8 inch electrode Flat 85-115 23 8 Horizontal 80-110 23 8 5/32 inch electrode Flat . 115-145 24 8 Horizontal 110-140 24 8 3/16 inch electrode Fl'at 145-185 25 8 (4) Clad pre- and post-heat treatment and interpass temperature for each clad layer:

Pre-heat at 250 F minimum and held until all cladding and a post weld heat treatment was completed. The interpass temperature was 350 F maximum and the post heat treatment temperature was 1150 + 250F

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-(5) Vessel stress relief treatment:

0 Intermediate PNHT = 1100 0F and held for 15 minutes.

0 Final PWHT = 1150 1 25 F and held for one hour per inch of weld thickness.

, (6) Manufacturer or subcontractor who fabricated vessel and applied nozzle cladding.

Combustion . Engineering at' Chattanooga, Tennessee.

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