ML19324C173

Discusses Proposed Alternative to ASME Section XI & Forwards Rev 2 to SIR-89-044, Davis-Besse Nuclear Power Station Hpi/ Makeup Nozzle Weld Overlay Repair Contingency Plan.

ML19324C173
Person / Time
Site:	Davis Besse
Issue date:	11/08/1989
From:	Shelton D TOLEDO EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML19324C174	List: ML19324C173 ML19324C176
References
1726, NUDOCS 8911150127
Download: ML19324C173 (3)

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. TOLEDO EDISON A Centenor Energy Convag DONALD C SHELTON wa pe.o.nt -ww Docket Number 50-346- 1d'894S" License Number NPF-3 Serial Number 1726 November 8, 1989

United' States Nuclear ~ Regulatory Commission Document Control Desk Vashington, D. C. 20555 -

Subject:

Proposed Alternative to ASME Section XI: Makeup /High Pressure Injection Nozrle Potential Veld Overlay Gentlemen:

On July 2, 1988, during a combined ASME Section XI and pre . fueling visual inspection two metallic pieces were discovered in the Davis-Besse Nuclear Power Station (DBNPS) Unit I reactor vessel which were later determined to be a portion of a makeup /high pressure injection (HPI) nozzle thermal sleeve.

Approximately three inches of the thermal sleeve had broken off from the end of the sleeve which protrudes into the reactor coolant system (RCS) cold leg.

This condition permitted cold water impingement directly on the cladding.

Inspection of the makeup /HPI nozzle revealed linear indications throughout the area where the thermal sleeve had failed. A conservative analysis was l performed (the results were submitted to NRC under Serial Number 1580 dated i september 15, 1988) which indicated that with the thermal sleeve intact the potential crack growth is acceptable for the 40-year lifetime of the unit.

. Toledo Edison submitted by letter (Serial Number 1664 dated June 19, 1989) l l

progress of the preparations and evaluations being performed for the sixth ,

refueling outage in regards to action to be taken on this item.

, Serial Number i 1664 discussed the plans to perform visual inspection of the thermal sleeve t

'. and ultrasonic examinations of the nozzle. The submittal indicated-that while  !

Toledo Edison does not expect to discover additional crack growth in the  !

nozzle, in case the inspection of the nozzle does reveal additional defects, '

. propagation of the as-left condition, or indications outside the dimensions s i

described in the existing analysis, contingency plans have been established  !

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and details are being developed to perform one or more of several actions. '

One of the potential actions includes veld overlay reinforcement of the nozzle. Veld overlay of the nozzle vould require NRC approval of the technique as a proposed alternative to ASME Section XI requirements as allowed by 10CFR50.55a.

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8911150127 891108 A047 PDR ADOOK 05000346 P ' \

PDC ,

THE TOLEDO EDISON COMPANY EDISON PLAZA 300 MADISON AVENUE TOLEDO, OHIO 43652

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. Docket Number 50-346

, , ticen n Number NPF-3 Serial Number 1726 Page 2 As discussed in the attached report (Numbet $1R-P9-044) of Structural ,

Integrity Associates (SIA), it is not anticipated that veld overlay on the  :

norsle vill be needed unless flavs have propagated to a depth of 1.6 inches. '

The attachment discusses fracture mechanics analyses and the design methodology of the veld overlay.

If the veld overlay described in the attachment is performed, Toledo Edison curres.i.ly plans to contract with Velding Services, Inc. to perform the ovsrlay. Velding Services, Inc. holds an ASME Section III "NR" Certification of Authorization for nuclear repairs. The veld overlay activity vill be ,

performed utilizing the appropriate OA requirements and velding specifications in accordance with ASME Section III and IX. The non-destructive examination (NDE) for the overlay would involve examinations of the original surface, the first veld layer, and the completed overlay. The techniques utilized vould be magnetic particle for the original surface and the first veld layer examinations and ultrasonic for the acceptance examinations of the completed  ;

overlay. The magnetic particle examinations vould be performed in accordance with ASME Section III and Section V criteria. The acceptance examination vould consist of two separate ultrasonic examinations. The bond between the norrle base retal and the veld overlay vould be examined by a straight beam technique. The entire veld overlsy deposit vould be examined using a 45 degree angle beam in order to verify freedom from veld defect inclusions.

ihese examinations vould also be perforned in accordance with ASME Section III.

Although it is unlikely that veld overlay of the norrle vill be necescary, Toledo Edison requecto NF.C approval of this veld overlay methodology to rupport coatingency planning and scheduling for the six;h refueling outage.

Veld overlay is not an approved repair technique under ASME Section XI.

Therefore, Toledo Edison requestr the NP.C approve the veld overlay of the corrle as a proposed alternative to the requirements of ASME Section XI as allovtd by 10CPR50.55a(a)(3). Toledo Edison requests NRC approval of this preposed alternative by December 15, 1989. .

i Should further information be required, please contact Mr. R. V. Schrauder, l Nuclear Licensing Manager, at (419) 249-2366.

Very tr ly yours, M

CBK/ssg Attachment cci P. M. Byron, DB-1 NRC Senior Resident Inspector A. B. Davis, Regional Administrator, NRC Region III j T. V. Vambach, NRC/NRR DB-1 Senior project Manager State of Ohio i

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Structural Integrity Associates Report Number SIR-89-044 i j, .'

Davis-lesse Nuclear Power Station RFI/ Makeup Nossle i-Veld' Overlay Repair Contingency Plan d

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