ML17222A562

Eddy Current Exam of Steam Generator Tubing During Oct 1987.

ML17222A562
Person / Time
Site:	Saint Lucie
Issue date:	10/31/1988
From:	FLORIDA POWER & LIGHT CO.
To:
Shared Package
ML17222A563	List: ML17222A562 ML17339A098
References
NUDOCS 8811010413
Download: ML17222A562 (12)

Text

Florida Power & Light Company St. Lucie Unit f2 Nuclear, Plant Special Report For DDY CURRENT EXAMINATION OF STEAM GENERATOR TUBING DURING OCTOBER, 1987 Nuclear Energy Services Materials, Codes and Inspections Department Juno Beach, Florida 33408 SSi10104i3 8S1024 PDR ADOCK 05000389 9 PDC

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Introduction The Nuclear Energy Services, Materials, Codes & Inspection Department, conducted an inservice eddy current examination of the Florida Power & Light St. Lucie Unit g2 Steam Generator Tubing in October, 1987. The extent of this examination included 1004 of non-plugged hot leg and cold leg tubes in accordance with plant technical specifications using multi-frequency eddy current equipment and differential bobbin coil test probes. The eddy current data was subjected to two independent analyses using certified data analysts from Combustion Engineering, NDE Technology and Zetec, Inc.

Discrepancies in the independent analyses were resolved by Level III individuals from the respective agencies.

St. Lucie Unit g2 contains two Combustion Engineering series 67 recirculating steam generators identified as PSL-2A and PSL-2B. Each steam generator contains approximately 8,411 u-bend tubes made of inconel 600. A baseline eddy current examination was performed in July, 1982 and the first inservice eddy current examination was performed in October, 1984. An unscheduled inservice eddy current examination was last performed in March, 1985, due to primary to secondary tube leakage which was identified and attributed to flow; induced vibrational wear at the diagonal and vertical support straps, referred to as batwings (Figures 1 and 2). To obtain wear progression data, 29 tubes which were plugged in March, 1985 were de-plugged in April, 1986 and examined using a standard bobbin coil and a segmented bobbin coil probe. The segmented bobbin coil probe provides wear data at both sides of the tube in contact with the batwing. The results of this wear progression analyses is presented in Combustion Engineering report CEN-328 dated May, 1986. Application of

'he wear progression model and conservative management practice during the October, 1987 outage resulted in "preventive maintenance plugging" of six (6) additional tubes in PSL-2A and two (2) additional tubes in PSL-2B. Table 1 provides a summary by steam generator of tubes examined, indications of tube wall penetration and tubes plugged.

Table 2 provides a listing of tubes plugged as a result of the October, 1987 examination and application of wear progression models. Refer to Figure 1 as a key to location codes. A total of 8 tubes were plugged in the PSL-2A generator and 10 tubes were plugged in the PSL-2B generator. Seven (7) tubes in PSL-2A were plugged as a result of wear at batwing or vertical support straps. One (1) tube was plugged as a result of wear from a foreign object; identified by visual examination to be a length of weld wire at the periphery of the tube bundle. Ten (10) tubes were plugged in PSL-2B as a result of wear at batwing or vertical support straps.

Table 3 provides a listing of all indications of tube wall penetration by location for each steam generator.

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A number of tubes had indications located at the batwing areas which represent the initiation of tube wall damage from vibration as discussed above. However, the wear at these areas has not advanced to the point which will produce a measurable result in terms of wall penetration. Therefore, these indications are identified in the eddy current database and the affected tubes will be monitored during subsequent examinations or otherwise dispositioned.

PSL-2A PSL-28 V2 V4 vl~ ~v5 DH- (Top) - (Top)

(Bottom) - (8ot tom) 09H 09C 38.25" OOH- 08C 38.25" 07H 070 37.5" 06H 05H f I 35.0e 32.0" 06C 050 04H li 04C 37.5w 03H f

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35. 0" 02H 020 OIH I! II I 32.0" OIC TSH 28.0" TSC.

TEH 21. 5 TEC INLET OUTLET le Ct'atea ~ Kiev. 1 to 7 Drilled Supporte

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~ Elev. 8 & 9 LUCIK II STEAK GENERATOR ARRANGEMENT Figure 1

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~APE BEND RFG!ON TVBE, 5UPPORT5 PLANT ST. LUClK UNlT 2 Figure 2

TABLE 1 St. Lucie Unit 2 Summa of Inservice Edd Current Examination Results for October 1987 PSL-2A PSL-2B TOTAL TUBES EXAMINED Indications of Wall Penetration IND Less than 204 337 186 20 to 394 27 16 40 to 1004 2 9 Total 366 211 Tubes Plugged based on Wear Progression Analysis and Management Conservatism Tubes Plugged Which Exceeded Plugging Limits Total Tubes Plugged 10 Total Tubes Plugged To Date 208 155

TABLE 2 St. Lucie Unit 2 Steam Generator Tubes Plu ed Durin the October 1987 Outa e Steam Generator A Line Row Indication Location 56 94 40 V4 59 133 40 DH 82 52 33 DC 92 42 37 DH 92 44 36 DH 94 40 34 DH 98 38 35 DC 130 116 33 TSH + 11.3 Steam Generator B Line Rov Indication Location 25 89 43 V2 38 96 51 V2 62 V4 69 133 45 V1 75 41 53 V3 80 48 33 DH 87 49 47 V3 88 46 47 V3 100 36 28 DC 100 92 42 V2 111 93 53 V2

St. Lucie Unit 2 Examination ram October 1987 Steam Generator PSL-2A List of all Tubes with Flaws 1

Line Row Indication Location 27 93 33 V4 + 1.0 33 105 31 V2 + 0.2 48 126 27 DH + 0.9 52 84 36 V3 + 0.2 56 94 25 V4 + 0.1 40 V4 + 0.9 57 95 32 V2 0.8 58 132 28 DH + 0.0 59 133 40 DH + 0.0 61 83 20 V3 + 0.9 64 94 29 V2 + 1.0 64 134 21 DH + 0.0 73 47 25 V3 + 0.9 81 47 20 V3 +- 0.8 82 52 33 DC + 0.0 87 69 24 5C + 8.9 91 109 34 TSC + 4.0 92 42 37 DH + 0.0 92 44 36 DH + 0.0 94 40 34 DH + 0.0 96 40 26 V3 0.7 96 50 30 V3 0.8 98 38 35 DC + 0.0 98 138 22 DH + 0.0 108 96 27 V2 + 0.7 117 113 22 5H + 29.7 127 53 22 V3 + 0.8 129 87 28 V3 + 0.7 130 116 33 TSH + 11.3

TABLE 3 St. Lucie Unit 2 Examination Pr ram October 1987 Steam Generator PSL-2B List of all Tubes with Flaws Line Row Indication Location 24 96 30 8H 1.0 25 89 43 V2 0.9 34 96 26 V2 + 0.5 38 96 51 V2 0' 62 V4 0.9 68 32 22 DH + 0.0 69 133 45 V1 + 0 '

75 41 53 V3 0.9 76 112 36 7C + 0 '

78 50 21 DC + 0.0 79 47 21 DH + 0.0 79 49 25 DC + 0.0 80 48 33 DH + 0.0 83 89 35 V3 0.7 87 49 47 V3 0' 88 46 47 V3 + 0 ~ 0 88 56 39 V3 + 0.8 97 97 26 TSH + 20.8 99 35 28 DC + 0.0 100 36 28 DC + 0.0 100 92 42 V2 0.9 111 93 53 V2 + 0.6 122 94 21 V2 1.1 123 97 23 V3 + 0.7 134 104 20 V1 + 0.5