ML20052G450

LER 82-002/01T-0:on 820428,during Eddy Current Exam, Discovered Abnormal Degradation in Fuel Cladding,Rcpb & Primary Containment.Seludge Lancing Will Be Performed

ML20052G450
Person / Time
Site:	Point Beach
Issue date:	05/12/1982
From:	Fay C WISCONSIN ELECTRIC POWER CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML20052G439	List: ML20052G438 ML20052G450
References
LER-82-002-01T, LER-82-2-1T, NUDOCS 8205180368
Download: ML20052G450 (4)

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NRC FORM 366 U. S.BUCLEAR REGULATORY COMMISSION (7 77) ,

LICENSEE EVEIMT REPORT CONTROL BLOCK: l l l l l l l (PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION) i e l0l1

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j REPORT DATE 7 60 61 DOCKET NUM8ER 68 69 EVENT DATE EVENT DESCRIPTION AND PROB ABLE CONSEQUENCES h ITiTil i On 04/16/82 Unit 2 was shutdown for refueling 8. Steam generator eddy l 10 l 3 ; l current started 04/24/82 and verification of the data for both SG's was l 10 pi] l completed on 04/29/82. The original inspection program and subsequent l 10 i s j l program expansions complied with the Tech. Spec. Seven tubes in the "A"l lOlsllSG and 6 tubes in the "B" SG were verified to have degradation in excess; l 0 l 7 l l of 40% , which is the plugging limit. This event is similar to others l t_O;glland reportable per Technical Specification 15.6.9.2.A.3. l 80 7 " 8 9 C DE CODE SU8CO E COMPONENT CODE S BC DE SU E O 9 lC ]B l@ [E_J@ l Dl@ l Hl Tl El Xl Cl Hl@ W@ [Zj 20_

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44 47 CAUF 3 OESCRIPTION AND CORRECTIVE ACTIONS h Iil O I l Six of the indications in the "A" SG were caused by IGA in the tubesheet I i i l crevice. The remaining one in the.~"A" SG and all the indications in the!

, 7 ]"B" SG are remnants of phosphate wastage at the top of the tubesheet. l lij,; l All degraded tubes were plugged on 04/29/82. Sludge lancing and a cre- l lii4j lvice flush will be performed in an attempt to reduce corrosion. l 7 8 9 80 STA S  % POWER OTHER STATUS IS O RY DISCOVERY DESCRIPTION I1 15 I b@ l 0 l 0 l 0 l@l N/A l l C l@l Eddy current examination l ACTIVITY CO TENT RELEASED OF RELEASE AMOUNT OF ACTIVITY LOCATION OF RELE ASE W W @ [Zj@l 7 8 9 to_

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PERSONNEL EXPOSURES NUMBER TYPE DESCRIPTION 1 7 l 0 l 0 l 0 l@l Zl@l N/A l PERSONNEL INJURIES NUMBER DESCRIPTION i a l 7 8 9 l 0 l 0 l 0 l@l12N/A 11 80 LOSS OF OR DAMAGE TO FACILITY TYPE DESCP'PTION l

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pr - q ATTACHMENT TO LICENSEE EVENT REPORT NO. 82-002/OlT-0 Wisconsin Electric Power Company Point Beach Nuclear Plant, Unit 2 Docket No. 50-301 On April 16, 1982, Unit 2 was shut down for its eighth annual refueling. Eddy current examination of the steam generators commenced on April 24, 1982. The original eddy current program for each steam generator was set up to meet the requirements of the Technical Specifications and Regulatory Guide 1.38. The "A" steam generator program consisted of inspecting 575 tubes through the U-bend. This included 276 tubes which were identified as having degradation in the hot leg during the Refueling 7 inspection. The "B" steam generator program consisted of inspecting 250 tubes through the U-bend and 31 tubes for the full length. The 250 tubes included 120 which were identified as having degradation in the hot leg during Refueling 7. All 31 tubes inspected for the full length had degradation identified in the cold leg during Refueling 7.

The eddy current program in both the "A" and "B" steam generator hot legs was expanded in accordance with the Technical Specifications as defects were identified. An expansion in excess of 200 tubes in the hot legs of both steam generators was performed after the original program. The results from the expansion in the "A" steam generator required an additional 400 tubes to be inspected, however, the program was expanded to include essentially all of the tubes in the area of concern.

Based on the results of the expansion in "A", the program in "B" was also expanded to include essentially all of the tubes in the area of concern. This expansion in "B" was not required by the Technical Specification but'was performed for prudent conservative engineering reasons. All the tubes in the expansion were inspected through the first tube support plate as the defects found were in the tubesheet region or just above the tubesheet. In excess of 60% of the tubes in the "A" steam generator and 50% of the tubes in the "B" steam generator were inspected.

A two-fold evaluation of the "B" steam generator cold leg indications was done to determine if it was necessary to expand the eddy current' program in the cold leg. First, the history of the tubes with indications was looked at. The percen-tage size of the indication was compared with what was reported for the previous five years. Second, the Level IIA evaluator did a direct comparison of this year's eddy current signal with last year's signal. Both comparisons indicated that there was not a significant change in the condition in the cold leg and 4 coupled with the exposure associated with setting up in the cold leg'an expansion was not conducted.

Jr The results of the eddy current inspection identified a total of 13 tubes which required plugging. The following table lists the tubes which required plugged along with three other tubes in the "A" steam generator which were plugged as a conservative measure.

"A" Steam Generator Hot Leq Tube Indication Locaulon R16C34 96% 5" Above Tube End R17C36 90% 5" Above Tube End R20C38 77% 6-9" Above Tube End R18C41 82% 8" Above Tube End R18C43 Undefinable 9-13" Above Tube End R17C45 Undefinable 12" Above Tube End R13C46 89% 14" Above Tube End R21C47 87% 14" Above Tube End R12C63 48% .5" Above Tubesheet R19C63 27% 14" Above Tube End "B" Steam Generator Hot Lcq Tube Indication Location R23C26 55% Top of Tubesheet R23C27 43% Top of Tubesheet R27C27 41% Top of Tubesheet R23C28 53% Top of Tubesheet R21C34 43% Top of Tubesheet R06C44 55% .5" Above Tubesheet All of the above listed tubes were mechanically plugged on April 29, 1982. All of the tubes with indications at the top of the tubesheet or above had identifiable indications during the 1981 refueling outage. Only one of the tubes with indications in the tubesheet area had an identified indication during the 1981 refueling outage. Tube R19C63 had a 25% indi-cation at 14" above the tube end in 1981.

The indications within the tubesheet area are believed to be the result of intergranular attack caused by caustic corrosion. The indications at the top of the tubesheet or above are believed to be remnants of phosphate wastage as evi-denced by the fact that they were noted during previous outages.

The called indications are not significantly greater than the plugging limit and for the most part the difference in com-parison to previous outages is within the expected range of scatter for small volume indications which are masked by a tubesheet signal.

3-In an attempt to reduce corrosion, the steam generators have been sludge lanced. Also, a crevice flush will be con-ducted prior to returning the unit to service. The crevice flush removes some of the corrosive materials from the crevice region.

This event is reportable in accordance with Technical Specification 15.6.9.2.A.3.

The Resident Inspector has been notified of this event.

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