ML20084H043
| ML20084H043 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 04/20/1984 |
| From: | Tucker H DUKE POWER CO. |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| SD-413-84-01, SD-413-84-1, NUDOCS 8405070429 | |
| Download: ML20084H043 (3) | |
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Mr. James P. O'Reilly, Regional Administrator U. S. Nuclear Regulatory Ccmnission Region II 101 Marietta Street, NW, Suito 2900 Atlanta, Georgia 30303 Re: Catawba Nuclear Station Unit 1 Docket No. 50-413
Dear Mr. O'Reilly:
Please find attached an interim report on corrective actions taken on Significant Deficiency No. 413/84-01.
Very truly yours, b
/gj Hal B. Tucker LTP/php Attachment cc: Director INPO Records Center Office of Inspection and Enforement Suite 1500 U. S. Nuclear Regulatory Ccanission 1100 Circio 75 Parkway Washington, D. C. 20555 Atlanta, Georgia 30339 NBC Resident Inspector Mr. Robert Guild, Esq.
Catawba Nuclear Station Attorney-at-Law P. O. Box 12097 Palmetto Alliance Charleston, South Carolina 29412 2135 Devine Street Coltrnbla, South Carolina 29205 3405070429 840420 PDR ADCCK 05000413 g
PDR 1697
.I JPO/IIBT/LTP April 20, 1984 INTERIM REPORT CATAWBA NUCLEAR STATIQ4 REPORT NlbEER: SD 413/84-01 REPORP DATE:
April 20, 1984 fit.ILITY: Catawba Nuclear Station - Unit #1 IDENTIFICATIO4 OF DEFICIENCY:
During the cool-down stage of the hot functional test, Nuclear Production Department detected an increase in the coolant mkeup requirments. A search was mde, and a leaking socket weld was found in the Pesidual IIcat Renoval System (ND) in the Auxiliary Building. mis was identified m 01-03-84.
INITIAL REPORT:
On January 13, 1984, G. Nejfelt, NFC Regim II, Atlanta, Georgia, was notified of the subject deficiency by W. O. llenry, L. M. Coggins, J. K.
Derry, and R. L. Williams of Duke Power Cmpany, 01arlotte, North Carolina, 28242.
DESCRIPTIOJ OF DEFICIENCY:
Our investigation found that a 2" socket weld (IND66-35) had developed a crack in the weld nutal extending approximately 300 around the circumference of the weld. mis weld is a socket weld joining 2" pipe to a socket weld half coupling. W e 2" line provides water to letdown heat exchanger for cleanup during refueling. mile investigating this prob 1cm in the "A" Train, a similar problem was found in the "B" Train. In the latter case, another 2" socket (IND66-6) had developed a crack. mis weld joined 2" pipe to a socket weld valve. This crack extended approximately 700 around the circum-ference of the pipe and was at the juncture of the weld metal arxl pipe base material.
% e two socket wolds have been rm oved and a metallurigical evaluation performyl. mis consisted of sectiming, polishing, and etching the cross section of the weld for optical microscopy. We also separated the cracked sections and examined the fracture surface using a scanning electron micro-scope.
Each of the two lines in question cmtain a notor operated valve. %ere are spring supports on the notor operators to support the weight of the valves; and on the "A" Train notor operator, there is a restraint to control seismic vibration. The supports on the valves had been disconnected for valve main-tenance. Stress Analysis revimx1 the systms with and without the supports.
W e conclusions of our evaluations to date are as follows:
1.
to system is adequately supported for all normal design loads.
2.
%c socket welds not code requirements.
JPO/HBT/IiT Catawba Nuclear Station - Unit #1 Ibport Nunber: SD 413/84-01 Ibport Date:
Anvil 20. 1984 3.
The possible cause of the weld failures was low cycle fatigue induced by vibration within the system. 'Ihis condition may have been aggrevated by the absence of the valve supports mentioned above.
ANALYSIS OF SAFETY IMPLICATICNS:
Had the leaks occurred during plant operation, any potential contamination would have been contained in the Auxiliary Building. However, assuming similar leaks in both trains, the intended safety ftrrtion of the Residual Heat Benoval bystem could possibly have been adversely affected.
CORRECTIVE ACTIO1:
Subsequent to our report of February 13, 1984 some vibration testing has been done. h is testing was done on March 13, 1984 on the "A" Train with no unacceptable vibration detected. 'Ihese tests were performed at 69 F and approximately 200 psig. vb were limited to these conditions because the system was " cold" and the reactor vessel head was not in place.
Additional testing will be performed subsequent to fuel loading. his 0
testing will be done at the 350 F plateau of the heat-up cycle. Beyond this point, the ND System would be isolated. As an additional means of assurance, the piping in question will be mxtitored by visual observation at least once in each 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> period. mis nonitoring would connence upon operation of the effected portion of the ND System and be terminated upon isolation of the ND System frcm the NC System.
i We have cxximitted to issue a supplementary report by August 13, 1984. 21s date is contingent upon fuel loading and heat-up as currently scheduled.
'DiIS IS AN INTERIM REPORT RIR:neg 04-17-84
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