ML20011F577

Forwards Special Rept 90-003 Reporting on Steam Generator Eddy Current Insp,Per Tech Spec 4.4.5.5.a.Rept Includes Number & Extent of Tubes Inspected & Location & Percent of Wall Thickness Penetration for Each Indication

ML20011F577
Person / Time
Site:	Crystal River
Issue date:	02/21/1990
From:	Beard P FLORIDA POWER CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
3F0290-08, 3F290-8, 90-003, 90-3, NUDOCS 9003060299
Download: ML20011F577 (8)

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C O R. P O R A 14 0 N February 21, 1990 3F0290-08 U S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555

Subject:

Crystal River Unit 3 Docket No. 50-302 Operating License No. DPR-72 Special Report 90-003.

Dear Sir:

The attached Special Report 90-003 entitled " Report on Steam Generator Eddy Current Inspection" is submitted in accordance with Technical Specifications 4.4.5 5.b and 6.9.2.(g). Technical Specification 4.4.5.5.a requires a 15-day

-report-to the NRC when a steam generator tube is plugged. The 15-day report was made in FPC's April 7,1989 letter.

Sincerely, P.M. Beard, Jr.-

Senior Vice President

. Nuclear Operations PMB/JWT Ia

' Attachment-ggg xc: Regional Administrator, Region 11

-Senior Resident Inspector

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- GENERAL OFFICE: 3201 Thirty fourth Street South

• P.O. Box 14042

• St. Petersburg, Florida 33733 * (813) 866 5151 g :_ A Florida Progress Company

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SPECIAL REPORT 90-001 REPORT ON STEAN GENERATOR EDDY CURRENT INSPECTION The following information in this Special Report is prepared in accordance with the requirements of Technical Specification 4.4.5.5.b. The report includes:

1. The Number and extent of tubes inspected.

2. The location and percent of wall thickness penetration for each indication. ,

3. Signal / Noise indications, indications < 20% through wall, indications 20 -39% through wall, and indications 40% through wall or greater.

4. Identification of tubes plugged. -

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1.0 INTRODUCTION

The Inconel 600 tubing in the two once-through steam generators (OTSG's) at Florida Power Corporation's Crystal River Unit 3 was inspected.during a scheduled reactor coolant pump outage in March, 1989. The code examination of the 0.625" nominal OD x 0.037" nominal wall tubing was performed by Babcock and Wilcox (B&W) Company personnel using standard bobbin coil techniques. Supplemental examinations were performed using a multi-element 8x1 probe and B&W's EDDY-360 rotating pancake coil probe.

This report documents the results of these examinations.

2.0

SUMMARY

The following table summarizes the results found during this inspection:

TABLE 1 OTSG "A" 0TSG "B" B0BBIN 8X1 EDDY-360 B0BBIN 8X1 EDDY-360 TUBES INSPECTED 2464 382 13 1738 368 25 IND'S 40-100% TW l 0 1 0 0 0 IND'S 20-39% TW 8 3 7 2 4 5 IND'S <20% TW 11 1 2 12 0 10 S/N INDICATIONS 34 0 0 14 8 0 0 NOTE: S/N indicates that the signal-to-noise ratio for an indication is too low for an accurate through-wall depth (TW) to be made.

OTSG "A" 0TSG "B" TUBES PLUGGED (71-61) 1 Tube No Tubes Plugged 3.0 EXAMINATION The examination, equipment, and personnel were in compliance with the requirements of the Babcock and Wilcox SPIS QA Manual for Inservice Inspection, the CR-3 technical specifications, Section XI of the ASME Boiler and Pressure Vessel Code,1983 Edition through the Summer 1983 Addenda, and industry standards.

The steam generator tubing examinations were performed by technicians qualified to level I, under the direct supervision of personnel qualified to Level II in accordance with B&W Personnel Qualification Procedure ISI-

24. The data was evaluated by personnel qualified to a minimum of Level IIA in accordance with Procedure ISI-24. The examination and evaluation procedures used during the eddy current inspection were approved by personnel qualified to Level III in accordance with Procedure ISI-24, 4 l

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>,A All examinations were conducted from the outlet of the steam generator.

The acquisition of the data was performed using Zetec's MIZ-18 System. Eddy current analysis was performed using Zetec's DDA-4, Edition 18.6 Rev. 5 Data Analysis Software. Site specific analysis guidelines were incorporated into the evaluation process.

Bobbin coil examinations were performed using 0.510" diameter probes in OTSG "A" and 0.500" diameter probes in OTSG "B". Upper tubesheet (UTS) tube-end damage in OTSG "B" resulted in the use of a smaller diameter probe to allow probe passage though the upper tube end. Frequencies of 600, 400, 200, and 35 kHz operating in the differential and. absolute modes were utilized. The 400 and 200 kHz differential frequencies were _ mixed to enhance defect detection at tube support plate intersections.

The multi-element 8x1 probe examination was performed using frequencies of 400 and 150 kHz in the. absolute mode. This examination was performed to identify any indications that may have been missed due to the bobbin coils' inherent limitation of ~ detecting circumferential cracks, to determine circumferential extent' of any indication detected, and to further substantiate the bobbin coil techniques. The tube sample inspected by the 8xl probe was limited to the lane and wedge regions of both generators.  !

The EDDY-360 examinations, using a B&W straight EDDY-360 probe, were performed at frequencies of 290 and 150 kHz operating in the absolute mode.

The frequencies were generated with a Zetec MIZ-18 remote data acquisition unit. The EDDY-360 probe was rotated through the tube at' four revolutions per second as a probe driver mechanically indexed the probe axially at 0.1 inch per revolution, resulting in an inspection speed of approximately 0.4 inches per second. The probe driver and all eddy current parameters were t computer controlled utilizing B&W designed software. The eddy current data was stored on digital data tapes.

The 290 kHz channel was utilized as the primary examination frequency. An

, amplitude curve was used to estimate percent-through-wall depths. Curves L plotting signal amplitude versus % TW were derived using a tubing calibration standard containing ID and 00 axial and circumferential EDM ~

notches. The data points used to generate these curves were stored in the setup files on the " Eddy" disk of the software operating package.

Official results of the data analysis were recorded on DDA-4 data disks, l then loaded into B&W's Eddy Current Data Management System. This system was used to check data for invalid entries, to perform data sorting routines, and to ensure that all of the proper tubes and locations were examined. The data sheets with the final analysis results were complied and printed using this system. The original eddy current data tapes have been provided to Florida Power Corporation.

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'l 4.0 RESULTS ,

'4'.1- OTSG "A" ,

A total of 2464 tubes were examined during _this outage using the standard ,

bobbin coil technique, and 382 tubes selected from the lane and wedge regions were examined with the multi-element 8xl probe. In addition, 13 tubes were examined with the EDDY 360 probe, o Based on bobbin coil data, one tube exhibited an indication of 140% through wall (TW), eight tubes exhibited indications of 20-39% TW,11 tubes exhibited tube degradation'<20% TW, and 34 tubes contained indications with a signal-to-noise ratio (S/N).

o 8x1. data reported three-tubes exhibiting indications of 20-39%

TW and one tube exhibiting an indication of <20% TW.

o EDDY-360 data reported one tube exhibiting an indication of 140%

TW, seven tubes exhibiting indications of 20-39% TW, and two tubes exhibiting indications of <20% TW.

o One tube (71-61) was removed from service based on a 55% TW indication located just below the upper tubesheet face (UTSF-0.3").

4.2. OTSG "B" A total of 1738 tubes were examined during this outage using the standard bobbin coil technique, and 366 tubes selected from the lane and wedge regions were examined with the multi-element 8xl probe. In addition, 25 tubes were examined with the EDDY-360 probe, o Bobbin coil 'Jata reported two tubes exhibiting indications of 20-39% TW,12 tubes exhibiting indications of <20% TW, and 48 tubes exhibiting S/N indications.

L o 8xl data reported four tubes exhibiting indications of 20-39% TW.

-o EDDY-360 data reported five tubes exhibiting indications of 20-39% TW and ten tubes exhibiting <20%-TW indications, o No tubes were found to have pluggable indications in excess of 40% TW.

4.3 GENERAL INFORMATION L A comparison of bobbin, 8x1, and EDDY-360 calls can be found in Tables 2 and 3 for OTSG's "A" and "B", respectively. Also, in Table 2 the calls indicative of wear in the lane region from the 9th to the 15th tube support

plates can be-found. Tubes examined with EDDY-360 were selected with FPC's concurrence from previous history, 8x1, and bobbin coil indications.

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j 4.4 SECONDARY REVIEW A secondary review was performed on all bobbin coil dita utilizing B&W's Automated Data Screening (ADS) system. The purpose of this secondary review was to ensure a complete and-accurate primary analysis was accomplished.

There was a very close correlation between the results of primary and 4 secondary review during this outage. Any discrepancies between the primary analyst and ADS were resolved by the on-site B&W Level III. The final data sheets reflect the results of the resolved primary and secondary analysis.

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TABLE 2 OTSG."A" COMPARIS0N OF B0BBIN COIL, 8x1, AND EDDY-360 RESULTS BOBBIN 8x1 E-360 t TUBE LOCATION %TW %TW %TW COMMENTS 16-41 lith TSP + 15.30" 20

• 14 ODI 22-69 8TH TSP + 34.50" 18 *

• ODI 24-89 13TH TSP + 30.70" 13 *

• ODI 29-73 3RD TSP + 12.00" 5 *

• ODI 35-59 12th TSP + 10.20" 20

• 22 ODI 42-68 -11TH TSP + 2.80" *

• 2 ODI 47-58 STH TSP + 20.00" 17 *

• ODI 54-71 8TH TSP + 20.90" 14 *

• ODI 56-3 10th TSP + 0.00" 24

• NDD ODI  ;58-125 13th TSP + 24.60" 20

• 27 ODI  :

LTSF + 20.80" 11 *

• ODI LTSF + 32.80" 17 *

• ODI I 61-1 9th TSP + 0.00" S/N

• 4 ODI [

64-127 10th TSP + 0.00" 38

• 22 Wear  !

71-61 UlSF + 0.30" 55

• 61 ODI/ plugged ";

77-3 15th TSP + 0.00"

• 37 27 Wear 77-4 15th TSP 0.00"

• 38 22 Wear 77-5 15th TSP + 0.00" 39 34 27 Wear 77-32 UTSF + 22.40"

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• ODI 77-124 9th TSP + 0.00" 37

• 21 Wear 10th TSP + 0.00" 34

• 20 Wear 78-123 8th TSP + 0.00" 26

• NDD Wear ODI - Outside Diameter Indication UTSF =' Upper Tube Sheet Secondary Face  ;

LTSF - Lower Tube Sheet Secondary Face i NDD. - No Detectable Damage j l TSP - Tube Support Plate '

• = Tube not inspected by this method.

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4 TABLE 3 ,

OTSG "B" COMPARIS0N OF B0BBIN C0ll, 8x1, AND EDDY-360 RESULTS BOBBIN 8x1 E-360 TUBE LOCATION %TW %TW  % TW COMMENTS 7-11 12th TSP + 24.40"

• 11 NDD ODI 7-20 7th TSP + 0.00" 6

• NDD ODI 7-29 7th TSP - 1.50" 12

• NDD ODI 23-68 LTSF - 13.00" 2 *

• ODI 10-12 9th TSP - 1.50" S/N

• 15 ODI 28-93 8th TSP - 1.50" 37

• 20 ODI

.31-7 8th TSP - 1.50" 5

• NDD ODI 37-8 7th TSP + 0.00" 10

• NDD ODI 40 8 7th TSP + 0.00" 10

• NDD ODI 46-83 LTSF + 2.50" 8

• 13 ODI 52-15 3rd' TSP - 1.50"

• 5 001 S/N 59-113 7th TSP - 1.50" S/N

• 3 ODI 62-7 15th TSP + 24.20"

• 16 ODI S/N 15th TSP + 20.00" S/N 16 ODI 64-114 4th TSP + 0.00" 28

• 24 ODI 67-52 7th TSP - 1.50" S/N

• 4 ODI 73 14th TSP - 9.00"

• 20 19 ODI 77-12 UTSF + 20.50"

• 29 26 ODI 78-13 UTSF + 20.90"

• 23 25 ODI UTSF + 16.00"

• NDD 19 ODI 79-4 15th TSP 14.50"

• 32 35 ODI 82-6 9th TSP - 1.50" 11

• 4 ODI 105-33 LTSF + 8.70" 13

• NDD ODI 106-32 LTSF + 6.70" 4

• NDD ODI 117-73 7th TSP + 1.50" 6

• NDD ODI 124-39 7th TSP - 1.50" NDD

• 7 ODI ODI - Outside Diameter Indication UTSF = Upper Tube Sheet Secondary Face

- LTSF = Lower Tube Sheet Secondary Face NDD - No Detectable Damage TSP = Tube Support Plate a * - Tube not inspected by this method.

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