ML20085J839

Ao:On 740611,during Unit Startup Small Leak Detected in Line 3-3037B Which Supplies Steam to Recombiner Booster Jet B.Caused by Defective Weld.Area Rewelded

ML20085J839
Person / Time
Site:	Dresden
Issue date:	06/18/1974
From:	Stephenson B COMMONWEALTH EDISON CO.
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20085J842	List: ML20085J839 ML20085J844
References
440-74, NUDOCS 8310190129
Download: ML20085J839 (3)

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. One Firsth2[onat Plaza. Chicago. Ilknots Address Rcply to: Post Othee Box 767 Chicago, Illinois 60690 BBS Ltr.f440-74 Dresden Nuclear Power Station R. R. #1 Morris, Illinois 60450 -s June 18, 1974 R! t... . O. ...

i Mr. J. F. O' Leary, Director 50-2 4S t JUN 241974'

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Directorate of Licensing M'!

U. S. Atomic Energy Connission ')s Washington, D. C. 20545 W ) ,' "'~ 0

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SUBJECT:

LICENSE _DPR-25, DRESDEN NUCLEAR POWER STATION. UNIT #3, REPORI OF ABSORMAL_0CCURRENCE PER SECTION 6.6.B l.a CF THE TECHNICAL SPECITICATIONS.

STEAM LINE SUPPLY TO "B" RECOMBINER BOOSTER JET LEAK.

References:

1) Notification of Region III of AEC Regulatory Operations Telephone: Mr. F. Maura, 1115 hours0.0129 days <br />0.31 hours <br />0.00184 weeks <br />4.242575e-4 months <br /> on June 11, 1974 Telegram: Mr. J. G. Keppler,1317 hours0.0152 days <br />0.366 hours <br />0.00218 weeks <br />5.011185e-4 months <br /> on June 11, 1974

2) P&ID M-345, M-371 Sheet #2

Dear Mr. O' Leary:

This letter is to report a condition relating to the operation of the unit at about 0400 hours0.00463 days <br />0.111 hours <br />6.613757e-4 weeks <br />1.522e-4 months <br /> on June 11, 1974. At this time, a small leak was detected in line #3-3037B which supplies steam to the "B" recom-biner booster jet.

This malfunction is contrary to section 1.A.5 of the Technical Specifications, which defines an abnonnel occurrence as an abnormal degradation of one of the several boundaries which are designed to contain the radioactive materials resulting from the fission process.

PROBLEM The problem was discovered when checking the "B" steam jet air ejector during unit startup. The line designated as 3-3037A-1\"B, was noted to be Icaking in the "B" ejector room where this new line had been tied into the "B" ejector steam foed line.

l The booster jet which is supplied by this line, along with the off gas preheater, are not in service at this time. They are part of the new "Off-Gas" system.

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M I 8310190129 740618 DR ADOCK 05000249 D I PDR COPY SENr REGION A

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.- O Mr. J. F. O' Leary O Jun2 18, 1974 i The leak was found in a weld at an elbow approximately 12 feet ,

from the tie in. The leak was subsequently determined to have been caused by slag inclusion in the weld.

When the leak was discovered, it was isolated by closing two root valves upstream of the leak. This Lumediate action was possible since the off gas system is not yet in service. The leak was stopped by closing these valves (not shown on P&ID).

The condition was corrected when it was found on June 11, 1974 at 0400 hours0.00463 days <br />0.111 hours <br />6.613757e-4 weeks <br />1.522e-4 months <br />.

The line which was leaking will supply steam to the "A" system booster jet and off gas preheater when the off gas system is placed in service.

INVESTIGATION When the weld was partially ground out to locate the actual source of the leak, a small pinhole was found. Approximately 1/3 of the weld was removed to allow revelding. When first pass was made slag flowed from area of pinhole indicating the source of the leak was slag inclusion.

The weld uns hydrestatically t+: A 4arlier in 197L sa part of the system installation testing and did not leak at ents time.

The cause of the failure is thus determined to be a defective weld.

CORRECTIVE ACTIONS The weld was partially ground out and was rewelded. Pressurizing the line with its normal steam source verified satisfactory repair.

No referrals for supplementary investigations are necessary.

EVALUATIONS There were no airborne or contamination problems resulting from the failure. The effect of the occurrence on safety of operation during the period of uncorrected condition was negligible. The area radiation monitors in the totally enclosed air ejector room would have detected the problem had it not been detected visually.

This occurrence did not jeopardize the safety of the plant or the public.

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Nr= J. F. O' Lea June 18, 1974 The inanediate action instituted was satisfactory and effective.

The nature of the failure is such that normal maintenance and operating inspections are adequate to prevent or minimize failures of this type on similar equipment. This occurrence poses no reason for limiting the future operation of Dresden Units 2 or 3.

Cumulative experience regarding miscellaneous contaminated steam line leaks of this nature is minimal. This type of small leak was not reportable until recently. Thus there is no conclusive recorded history available at this time.

Sincerely, ,_ / #

_ .[e f c t-s * * '~

B. B., tephenson Superintendent BBS:JD:do l

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