ML19352A117

Ro:On 741213,during Refueling Outage Circumferential Cracks Found in Unit 2 Stainless Steel Loop B Bypass Line.Cause Not Stated.Corrective Action Being Reviewed

ML19352A117
Person / Time
Site:	Dresden
Issue date:	12/16/1974
From:	COMMONWEALTH EDISON CO.
To:
References
NUDOCS 8103060474
Download: ML19352A117 (3)

Text

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Date: 12/16/74 No.

DIRECTORATE OF REGULATORY OPERATIONS _

NOTIFICATION OF AN INCIDENT OR OCCURRENCE Facility: COMMONWEALTH EDISON COMPANY (DRESDEN UNIT 2)

Problem: CRACKS IN 4" RECIRCULATION PIPING The licensee reported to a Region III inspector at the site on Dececber 13, 1974, that circumferential cracks had been found in the Dresden 2, 4" stainless steel "B" loop bypass line around the primary recirculation The failures were located downstream of the pump pump discharge valve. A similar crack discharge valve and cannot be isolated by system valves.

was located in the "A" bypass loop of Unit 2 on September 13, 1974.

(Reference Notification of an Incident or Occurrence Number 125, dated September 18, 1974.)

The following information was provided by the licensee in telephone conversa-tions on December 13 and 14, 1974, and from the Region III inspector at the plant on December 13, 1974: ,

1. The unit was in a efueling outage. The cracks were found visually following the grinding of the pipe wall surface in preparation for an ultrasonic test required by the in-service inspection program.

2. Subsequent ultrasonic testing indicated that two cracks"B" were present loop 4" l

in the heat affected zone of the veld which ties the One pipe to the veldolet connecting to the 28" recirculation header.

crack indication on the inside of the pipe is about 4"The longother extending crack circumferential1y from the 2 to 6 o' clock position.

indication is 1 1/2" long extending from the 7 to 8:30 o' clock position.

ultrasonically tested in mid September 1974. No

3. This weld had been crack indications had been detected at that time.

4. Ultrasonic inspection of the other velds in "B" loop revealed four other indications at weld joints as shown on the attached sketch.

The licensee is currently performing an ultrasonic test of the welds in the "A" loop.

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5. The licensee is currently reviewing corrective action.

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6. A press release of the failure is planned by the licensee.

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Action Taken by Regulatory Operations J

1. Region III inspectors were at the site on December 13, 1974, when the defect was found. Followup is continuing and further RO action is contingent on findings and generic implication.

2. A press release will be issued by Region III.

3. The Assistarts to the Commissioners, the Staff of the Joint Committee on Atomic Energy and the Office of Information Services have been notified by telephone.

4. A representative of the State of Illinois was informed.

Enclosure:

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" 799 ROOSEVELT ROAD GLEN ELLYN ILLINots 6o137 (3 t2) a ss.2e se December 16, 1974 H. D. Thornburg, Chief, Field Support and Enforcement Branch, Directorate of Regulatory Operations, Headquarters DIRECTORATE OF REGULATORY OPERATIONS NOTIFICATION OF AN INCIDENT OR OCCURRENCE - DRESDEN UNIT 2 CRACKS IN 4" RECIRCULATION PIPING The attached communication covering the preliminary information from the inspection conducted by the licensee of Dresden 2 cracks in 4" recirculation piping is forwarded with the recomendation that it be issued as a " Blue Sheet."

'$$G G. Fiorelli, Chief Operations Branch

Enclosure:

As above cc: S. E. Bryan, RO III Coordinator, RO:HQ J. O. Keppler, R0:III DR Central Files R0 Files S

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