ML17252A853

Letter Concerning an Occurrence Where a Small Leak Was Observed at the Upstream Orifice Flange Connection for Flow Transmitter 946D in the Six-Inch Residual Heat Removal System Return Line to No. 21 Reactor Coolant Loop - Indian Point Unit

ML17252A853
Person / Time
Site:	Indian Point
Issue date:	02/04/1974
From:	Cobean W R Con Edison, Consolidated Edison Co of New York
To:	O'Leary J F US Atomic Energy Commission (AEC)
References
4-2-4
Download: ML17252A853 (2)

Text

-Cons.olldated Edison Company of New . I. 4 Irving Place, New York, NY 10003 * * / _,,,..,* Mr. John F *-011Leary, Director Directorate of Off ice of Regulation U.S. Atomic Energy Commission Washington, D.C. 20545

Dear Mr. o:

Leary: February 4, 1974 Re: Indian Point Unit No. 2 Facility Operating License No. DPR-26, AO 4-2-4 The following report is provided pursuant to the requirements of Section 6.12.2 (a) of the Technical Specifications.to Facility Operating License DPR-26. During the course of a routine plant inspection on January 21, 1974, a small leak was observed at the upstream orifice flange connection for flow transmitter 946D in the six-inch Residual Heat Removal System return line (Line No. 335) to No. 21 reactor coolant loop. leak was at the base of a fillet attaching a 3/4" pipe to the orifice flange and was on the pipe side of the weld. At the time of-this observation, the reactor was in the cold shutdown condition with the Residual Heat Removal System in service and pressurized to about 400 psig. After depressurizing and draining the section of piping at the orifice flange, a dye penetrant ipspection of the weld area was performed to the extent of the* crack. The results of this inspection indicated a crack at the base of the -fillet weld approximately 120° around the --ir circumference. The faulty weld was then ground out. A dye penetrant check of the end of the pipe indicated that it was also cracked. Approximately a one-inch length of this 3/4" pipe, including the section that had a crack in it, was then cut off and sent to our metallurgical laboratory for further investigation and study. The socket in the flange was redressed and the new end of the pipe was reinserted and rewelded to the flange. This leak did not adversely affect the safe operation of Indian Point Unit No. 2 and was well within the makeup capabilities of the Chemical and Volume Control System. Had the plant been operating, the Residual Heat

-> . "' . . .. ...._ * ...---* Re: Indian Point Unit No. 2 Facility Operating License DPR-26, AO 4-2-4 (cont'd.) Removal System would have been isolated from the Reactor Coolant System and, therefore, would hot have experienced primary system pressure. For these reasons, the safety implications of the leakage are considered negligible. Very truly yours, Warren R. Cobean, Jr. J jm cc: James P. O'Reilly