ML20206S284

Summary of 990427 Telcon with Util Re Recent Secondary Side SG Insp Activities at Plant,Unit 2.Replacement SGs Are Planned to Be Installed in Spring 2002 for Units 1 & 2

ML20206S284
Person / Time
Site:	Calvert Cliffs
Issue date:	05/19/1999
From:	Stephanie Coffin NRC (Affiliation Not Assigned)
To:	NRC (Affiliation Not Assigned)
References
NUDOCS 9905210088
Download: ML20206S284 (5)

Text

, MEMORANDUM TO: Fils l FROM: Stephania M. Coffin, Matsrials Engine::r Materials and Chemical Engineering Branch Division of Engineering

SUMMARY

OF APRIL 27,1999 PHONE CALL BETWEEN NRC STAFF AND BGE REPRESENTATIVES TO DISCUSS STEAM GENERATOR INSPECTION ACTIVITIES I On April 27,1999, representatives of Baltimore Gas and Electric Company (BGE) and NRC staff discussed over the telephone recent secondary side steam generator inspection activities at Calvert Cliffs Unit 2. The BGE participants were Elliott Flick and Anthony Saccavino. The staff participant was Stephanie Coffin.

During the current refueling outage, BGE performed secondary side visualinspections of the eggcrate tube supports in the periphery of the steam generators on both the hot and cold leg sides in the #21 and #22 steam generators. In the #21 steam generator, the licensee I documented minor degradation of the eggerate supports on the hot leg side at the 6",7*, and l 8* support elevations. In the #22 steam generator, the licensee performed similar inspections '

and found more extensive degradation of the eggcrate supports on the hot leg side at the 7" and 8* support elevations as well as on the cold leg side at the 6* support elevation. All the tubes in both steam generators were adequately supported. BGE preventatively plugged 4 i tubes in the #21 steam generator and 98 tubes in the #22 steam generator to address the l potential for continued degradation over the next operating cycle. Based on the location and nature of the degradation, BGE concluded the cause of the degradation is erosion corrosion, similar to, but much less extensive than that seen at San Onofre Unit 3. The San Onofre experience is discussed briefly in Generic Letter (GL) 97-06, " Degradation of Steam Generator Internals." The licensee performed an upper bundle flush and sludge lancing of the steam generators this outage and plans to adjust chemistry levels to improve resistance to erosion corrosion over the next operating cycle. BGE will reinspect the secondary side of the steam ,

generators during the next refueling outage to ascertain the effectiveness of the corrective l actions.

BGE performed similar secondary side inspections at Calvert Cliffs Unit 1 in 1996 and 1998 and documented no eggerate degradation.

The staff notes that the Combustion Engineering Owners Group ranked Calvert Cliffs Unit 2 as one of the most susceptible plants to this type of degradation, based on feodwater iron i transport rates, as documented in BGE's response to GL 97-06. Replacement steam generators are planned to be installed in the Spring 2002 for Calvert Cliffs Unit 1 and Spring 2003 for Calvert Cliffs Unit 2. l The staff provided a draft of this phone call summary to BGE to allow them the opportunity to ,

comment on the summary prior to issuance.

3 Docket Nos. 50-317 and 50-318 dL.

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Office DE:EMCB E DE:EMCB s Name SMCoffin iN EJSullivan Date 5/11/99 / /

ORIGINAL RECORD COPY

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e 2-The staff provided a draft of this phone call summary to BGE to allow them the opportunity to comment on the summary prior to issuance.

Docket Nos. 50-317 and 50-318 Distribution t Alex Dromerick Docket Files . e EMCB RF Bill Bateman Emmett Murphy DOCUMENT NAME: G:\EMCB\sg-files \CALVERT\ UNIT _2\eggcrate.wpd To receive a copy of this doctanent. lndicate in the bor *C* e Copy without attachment / enclosure "E" = Copy with attachment / enclosure *N' = No copy Office DE:EMCB E ,

Name SMCoffin 9" Date 5/19/99 ORIGINAL RECORD COPY l

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k 2 The staff provided a draft of this phone call summary to BGE to allow them the opportunity to comment on the summary prior to issuance.

Docket Nos. 50 317 and 50-318 Distribution Alex Dromerick Docket Files PUBLIC EMCB RF Bill Bateman Emmett Murphy DOCUMENT NAME:

To,.c.i..novoen.ooe- G:\EMCB\s me.c. men.w. g-files \CALVERT\ UNIT _2\eggerate.wpd c . c. . noui .n.cnm.nv.ncio.u,. r . cm .,n .,i.enm.nie.ncio.u,. v . No copy Office DE:EMCB E Name SMCoffin W Date 5/19/99 ORIGINAL RECORD COPY j

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2 j NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20006 0001

,o May 19, 1999 MEMORANDUM TO: Edmund J. Sullivan, Jr., Section Chief NDE & Metallurgy Section Materials and Chemical Engineering Branch FROM: Stephanie M. Coffin, Materials Engineek k NDE & Metallurgy Section N

Materials and Chemical Engineering Branch

SUMMARY

OF APRIL 27,1999 PHONE CALL BETWEEN NRC STAFF AND BGE REPRESENTATIVES TO DISCUSS STEAM GENERATOR INSPECTION ACTIVITIES On April 27,1999, representatives of Baltimore Gas and Electric Company (BGE) and NRC staff discussed over the telephone recent secondary side steam generator inspection activities at Calvert Cliffs Unit 2. The BGE participants were Elliott Flick and Anthony Saccavino. The staff participant was Stephanie Coffin.

During the current refueling outage, BGE performed secondary side visualinspections of the eggerate tube supports in the periphery of the steam generators on both the hot and cold leg sides in the #21 and #22 steam generators, in the #21 steam generator, the licensee documented minor degradation of the eggerate supports on the hot leg side at the 6*,7*, and 8* support elevations. In the #22 steam generator, the licensee performed similar inspections and found more extensive degradation of the eggerate supports on the hot leg side at the 7*

and 8" support elevations as well as on the cold leg side at the 6* support elevation. All the tubes in both steam generators were adequately supported. BGE preventatively plugged 4 tubes in the #21 steam generator and 98 tubes in the #22 steam generator to address the potential for continued degradation over the next operating cycle. Based on the location and nature of the degradation, BGE concluded the cause of the degradation is erosion corrosion, similar to, but much less extensive than that seen at San Onofre Unit 3. The San Onofre experience is discussed briefly in Generic Letter (GL) 97-06, Degradation of Steam Generator internals." The licensee performed an upper bundle flush and sludge lancing of the steam generators this outage and plans to adjust chemistry levels to improve resistance to erosion corrosion over the next operating cycle. BGE will reinspect the secondary side of the steam generators during the next refueling outage to ascertain the effectiveness of the corrective actions. The staff views their corrective actions adequate at this time. We will continue to discuss this issue with BGE at their future outages.

BGE performed similar secondary side inspections at Calvert Cliffs Unit 1 in 1996 and 1998 and documented no eggerate degradation.

The staff notes that the Combustion Engineering Owners Group ranked Calvert Cliffs Unit 2 as one of the most susceptible plants to this type of degradation, based on feedwater iron transport rates, as documented in BGE's response to GL 97-06. Replacement steam generators, with stainless steel eggcrate supports, are planned to be installed in the Spring 2002 for Calvert Cliffs Unit 1 and Spring 2003 for Calvert Cliffs Unit 2.

'i I

The staff provided a draft of this phone call summary to BGE to allow them the opportunity to l comment on the summary prior to issuance.

Docket Nos. 50-317 and 50-318

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