ML20151K203

Safety Evaluation Supporting Repair of Jet Pump Instrumentation Penetration Nozzle

ML20151K203
Person / Time
Site:	Peach Bottom
Issue date:	06/20/1984
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20151K201	List: ML20151K195 ML20151K203
References
NUDOCS 8406270383
Download: ML20151K203 (3)

Text

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O ATTACHMENT SAFETY EVALUATION j REPAIR OF JET PUMP INSTRUMENTATION PENETRATION N0ZZLE PEACH BOTTOM UNIT 3 i

MATERIALS APPLICATION SECTION MATERIALS ENGINEERING BRANCH BACKGROUND Cracks have been found recently in several BWR Jet Pump Instrumentation

Penetration Nozzles. The cracks are concluded to be caused by IGSCC, and are similar to cracks in BWR piping. The guidelines for inspection, evaluation, and repair of these cracks provided in SECY-267C* and generic letter 84-11**. also apply to cracks in this component.

While down for an unscheduled maintenance outage, the licensee inspected the welds in this component on Peach Bottom Unit 3. Cracks were found in the safe end to reducer weld in both nozzles.

EVALUATION The licensee has submitted a report, " Repair to the Jet Pump Instrumentation Penetrations," da.ed June 20, 1984, and our SER is *-

based on this information and input from Region I.

• SECY-83-267C, " Staff Requirements for Reinspection of BWR Piping and Repair of Cracked Piping',', November /7, ~1983.

• • Generic Lettc r 84-11. " Inspections of BWR Stainless Steel Piping",

April 19,1984 Darrell G. Eisenhut, Director, Division of Licensing, USNRC.

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• PDR

7 Inspection Welds in the two (2) Jet Pump Instrumentation Penetration Nozzles were inspected using the same procedures as were required under Bulletin 83-02, using examiners that were qualified in accordance with the Bulletin.

Cracks were found in both nozzles at the safe end to reducer welds as follows:

Length Length Depth a/t Pipe Diameter Inches % Circumference Nozzle A 1.0 " 8% 48.6% 4" Nozzle B 1.87" 15% 100 % 4" Repair Repair was accomplished by weld overlay, designed and applied in accordance with staff guidelines.* The first layer was inspected, and then the required thickness of overlay was applied, with no credit taken for the thickness of the first layer. The thickness of the overlay was designed to provide full structural support, with a safety margin of 3. Material used for the weld overlay was type 308L, in accordance with staff guidelines.

• Generic Letter 84-11 and SECY-83-267C.

Additional assurance of future integrity will be provided by local leak detection equipment that has been installed at the location of the repairs.

! Staff Evaluation We have concluded that the inspections and repairs have been conducted in complete conformance with SECY-267C and 84-11 guidelines. Extra conservatism has been used in the analysis because the cracks are short, less than 20% of the circumference, and no structural credit was taken for the first layer of weld overlay.

Region I has concluded that the inspections were conducted properly, and are satisfied that all applicable staff and Code requirements were niet.

, We have concluded that the Peach Bottom Unit 3 Jet Instrumentation Penetration Nozzles have been inspected and repaired in accordance with all current staff gaidelines, and the plant can be safely -

! operated until the next refueling outage, l

l Dated: June 20, 1984 The following NRC staff personnel have contributed to this Safety Evaluation: W. Hazelton, W. Koo.

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