05000272/LER-1979-048-01, /01T-0 on 790709:during Normal Maint Operations, Significant Wear Marks Found on Tubes Adjacent to Tube Lane Blocking Devices.Caused by Movement of Blocking Devices. Steam Adjacent to Blocking Devices Were Plugged

/01T-0 on 790709:during Normal Maint Operations, Significant Wear Marks Found on Tubes Adjacent to Tube Lane Blocking Devices.Caused by Movement of Blocking Devices. Steam Adjacent to Blocking Devices Were Plugged

ML18079A619
Person / Time
Site:	Salem
Issue date:	07/20/1979
From:	Kapple A Public Service Enterprise Group
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML18079A618	List: 05000272/LER-1979-048, Forwards LER 79-048/01T-0 05000272/LER-1979-048-01, /01T-0 on 790709:during Normal Maint Operations, Significant Wear Marks Found on Tubes Adjacent to Tube Lane Blocking Devices.Caused by Movement of Blocking Devices. Steam Adjacent to Blocking Devices Were Plugged
References
LER-79-048-01T, LER-79-48-1T, NUDOCS 7907260586
Download: ML18079A619 (3)

LER-1979-048, /01T-0 on 790709:during Normal Maint Operations, Significant Wear Marks Found on Tubes Adjacent to Tube Lane Blocking Devices.Caused by Movement of Blocking Devices. Steam Adjacent to Blocking Devices Were Plugged

Event date:
Report date:
2721979048R01 - NRC Website

text

Report Number:

Report Date:

Occurrence Date:

• Facility:

7.48/0lT 7/20/79 7/9/79 Salem Generating Station Public Service Electric & Gas Company Hancocks Bridge, New Jersey 08038 IDENTIFICATION OF OCCURRENCE:

Degradation of Stearn Generator Tubes CONDITIONS PRIOR TO*OCCURRENCE:

Operational Mode 6 DESCRIPTION OF OCCURRENCE:

Six inch handholes in the lower section of each steam generator were removed during scheduled outage maintenance to perforrn sludge lancing.

Wear marks on several tubes adjacent to tube lane blocking devices on Nos. 11, 13 and 14 Steam Generators were sighted and investigated.

The largest wear marks were approximately l" long and 3/16" wide; most marks were somewhat smaller.

No significant wear marks were' visible upon ~nspection of the No. 12 steam generator by PSE&G and Westinghouse officials.

This is documented on Deficiency Report No. MD-584.

DESIGNATION OF APPARENT CAUSE OF OCCURRENCE:

Wear marks are attributed to movement of the tube lane blocking devices against adjacent tubes during steam generator operation.

Water flowing around.the blocking devices and possible improper installation by construction personnel prior to startup operation caused them to loosen with the passage of time and vibrate against the tubes.

ANALYSI~ OF OCCURRENCE:

Salem Unit N<?* 1 Technical Specification, Section 3.4.5 addresses the operability of the steam generators during normal operation and stipulates a plugging requirement for all tubes with imperfections exceeding the plugging limit of 40% of the tube nominal wall thick-ness.

By plugging a.11 inspected steam generator tubes which showed visual or eddy current degradation, the structural integrity of that portion of the Reactor Coolant System*has been maintained.

LER 79-48/0lT CORRECTIVE ACTION:

Eddy current testing was performed on a total of 30 tubes adjacent to the tube lane blocking devices in Nos. 11, 13 and 14 Steam Gen-erators.

Testing revealed that six tube ends in five tubes showed degradation greater than 40% of the nominal wall thickness.

Consequently, it was decided to perform explosive plugging on both ends 9f the 30 tubes adjacent to tube lane blocking devices in Nos. *11, 13 and 14 steam generators.

After completion of the plugging, photornapping was used to document the results.

The tube lane blocking devices were reinstalled by station maintenance personnel under direct supervision of the vendor.

FAILURE DATA:

Eddy current results greater than 40% nominal wall thickness:

Steam Generator No.

Location Tube No.

% Defect Depth 11 Inlet (Manway Side) 1-94-Tl

> 50 11 Inlet (Manway Side) l-91-T4 48 11 Outlet (Manway Side) l-91-T4.

63 11 Outlet (.Manway Side) l-92-T3 41 13 Inlet (Manway Side) l-92-T3 50 14 Inlet (Nozzle Side) l-3-T3 45 Prepared by __

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Manag!:?r !..sem Generating* Statior SORC Meeting No. ___

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T NUMBER 63 69 EVE"lT DATE 74 7o R!:?ORT OATE Sll EVENT DESCRIPTION AND PROBABLE CONSEQUENCES@

I During normal maintenance operations, significant wear marks on steaiu tubes adjacent to tube lane blocking devices were found on #11,~13 & *14 Steam Generators.

If T/S 3.4.5 plugging requirements are not followed for tubes with degraded wall thickness, the structural inteority of the!

((TI] I RCS will not be assured within acceptable limits.

This is the first [ill] I occurrence of this type.

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CODE TYPE NC.

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ATIACHM!:NT "1?AD-4 TAKEN ACTION ON PLANT METr;oD HOURS ~ SUBMITTED FORM ~us.

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42 CAUSE DESCRIPTION AND CORRECTlVE ACTIONS @

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.!7 [II)) Wear marks were caused bv movement of tube lane blocking devices which QIO loosen up with the passage of time and vibrate against adiacent stea.1"[1.

ITJJJ 1tubes.due*to water flow during S/G operation.

Steam tubes adjacent to

[!))] blocking devices in #11, #13 & #14 S/G's have been plugged.

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DISCOVERY DISCOVERY DESCRIPTION-~

W@I Discovered during sludae lancina in§!:Ctl.

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