ML20134H257
| ML20134H257 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 08/23/1985 |
| From: | Tucker H DUKE POWER CO. |
| To: | Adensam E, Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8508280339 | |
| Download: ML20134H257 (3) | |
Text
Duxn Powna GOMIRNY P.O. ISOX 03180 CIIAHLOTTE, N.C. u824u IIAL H. TUCKER retxenown veom roamineNT (70-4) 07:D -8531 NLLLRA. PatHetrCTMDN August 23, 1985 Mr. Harold R. Denton, Director Office of Ntaclear Regulation U.S. Nuclear Regulatory Commission Washington, D.C.
20555 Attention:
Ms. E. G. Adensam, Chief Licensing Branch No. 4 Regarding:
Catawba Nuclear Station Docket No. 50-413 and 50-414 Resolution of Outstanding Items on Diesel Generators
References:
1)
NRC letter to H. B. 'Ibcker, DPCo. from T. M. Novak of August 14, 1984.
2)
Safety Evaluation Report Catawba Nuclear Station Unit 1 -
Reliability of Diesel Generators Manufactured by Transamerica Delaval, Inc.
'JDI Project Group Division of Licensing.
3)
Failure Analysis Associates, " Metallurgical Analysis of Catawba Injection Port Isak", June,1984.
Dear Mr. Denton
%e purpose of this letter is to inform you of action that Duke Power Company is taking on cylinder heads for the Catawba diesel generators.
===1.
Background===
Four cylinder heads at Catawba, one on engine lA and three on engine 1B, developed small jacket water leaks into the fuel injection cavity. Se lA cylinder head has been examined by FaAA. Wis investigation (refer-ence 3) revealed that the leak was caused by a crack initiating from the corner of a welded-in plug where it was seated in the cylinder head as shown in Figure lA. Wis welded-in plug is reported by 'IDI to have been g.3 pg used to repair the casting around the fuel injector hole. Wis head as a.
well as the three heads on engine IB were replaced.
Reference 2, forwarded by reference 1, requested that Duke Power Coupany replace another head on diesel 1A (head 6L) where it was suspected, based on mo visual examination, that this head had the same welded-in plug. his head was subsequently replaced on diesel 1A. %e remaining heads on both og engines were inspected and we therefore believe that none of the cylinderheads on the Catawba Unit 1 diesels have weld repairs.
g 2.
Nrna of AcHnn LLL Since the inspection of Unit 1 diesels, Duke Power Conpany has developed pt an eddy current test (BCT) technique to be used in conjunction with the 9 s;
4 visual inspection to detect the partial penetration plug welds in cylin-der heads.
Results of both visual and ECT inspections on diesel 2A showed that five heads had been repaired with partial penetration welds. These heads have been replaced. Of the heads replaced three heads (cylinders 6L, 7L and 8L) are heads with no weld repair.
The other two replacement heads (cylinders 2R and 3R) have been repaired per Figure 1B. Results of the smee inspections on diesel 2B showed that no heads had plug repair welds.
Referring to Figure IB, the weld repair of the cylinder heads consists of welding a plug into the head, stress relieving the weld and machining the injector port back side of the plug out such that the repair is a full penetration weld. This repair is described on UDI drawing 102718, Rev.
O.
Cylinder heads at Catauba that have been repaired in this fashion are stamped llR. She full penetration weld eliminates the crack starter found in previous partial penetration weld repaired heads.
Post weld stress relieving reduces welding residual stresses to low levels. Thus, weld repaired castings with full penetration welds which are stress relieved are considered equivalent in quality to non weld repaired castings.
Very truly yours,
/
y H. B. Tucker, Vice President Nuclear Production HBT Sigissak ocs Dr. J. Nelson Grace, Regional Administrator U.S. Nuclear Regulatory Commission Region II 101 Marietta Street,Itt, Suite 2900 Atlanta, Georgia 30323 Robert Guild, Esq.
P.O. Box 12097 Omeleston, South Carolina 29412 g
Mr. Jesse L. Riley Carolina Environmental Study Group 854 Henley Place Carlotte, North Carolina 28207 Petimetto Alliance 2135-1/2 Devine Street Coltabia, South Carolina 29205 NRC Resident Inspector Catawba Nuclear Station
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/ FIR. DECK A. OLD HEAD REPAIR g
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NEW HEAD REPAIR FIGURE
- 1. CYLINDER HEAD REPAIR E
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