3F0792-02, Forwards 15-day Rept of Eddy Current Insp of once-through SG Tubes on 920629
| ML20101S351 | |
| Person / Time | |
|---|---|
| Site: | Crystal River  |
| Issue date: | 07/10/1992 |
| From: | Beard P FLORIDA POWER CORP. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 3F0792-02, 3F792-2, NUDOCS 9207170056 | |
| Download: ML20101S351 (11) | |
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Florida Power IIpsDN$eNU3 Docket No. 50-302 July 10, 1992 3F0792-02 U.S. Nuclear Regulatory Commission Attention:
Document Control Desk Washington, D.C.
20555
Subject:
Eddy Current Testing, Technical Specification Report
Reference:
FPC to NRC, 3F0392-02, dated March 30, 1997.
Dear Sir:
Florida Power Corporation (FPC) completed the Eddy Current (EC) inspection of Crystal River Unit 3's Once-Through Steam Generators (OTSGs) on June 29, 1992.
Attached please find the 15-day report submitted in accordance with Technical Specification (TS) 4.4.5.
The report contains sections on: Background summarizing FPC's changes to the inspection plan previously provided to the NRC in the referenced letter; Selection of Samples and Results describing sample size, its selection method and a description of the results; Tables A and B providing the number and location of plugged tubes in each 0TSG; Table C listing plugged tubes resulting from a suppiemental sample inspection performed in the B OTSG; and a Conclusion.
Sincerely, k
P. H. Beard, Jr..
Senior Vice president Nuclear Operations PMB/LVC Attachment xc:
Regional Administrator, Region II NRR Project Manager Senior Resident Inspector 100: Ua 9207170056 92071o DR ADOCY 0300 2
A Florida Progress Company I
=
EDDY CURRENT TESTING REPORT (PACE 1 0F 10)
GACKGROUND:
The reference letter provided FPC's inspection plan for the EC testing performed during Refuel 8.
FPC enhanced that inspection plan to provide further assurance of long term integrity of the CR-3 steam generators.
The enhanced inspection proceeded as follows:
A)
Inspected as planned all tubes -in the "A" SG which had not been previously inspected (43%) and approximately half of the tubes in the "B" SG (31%) which had not been inspected. The remaining 31%
of the tubes in the "B" SG was to be inspected in 9R (1994).
However, FPC expanded the inspection to test the remaining tubes (4535 tubes) in the "B"
SG.
Presently, all tubes in both steam generators have been inspected at least once since the baseline pre-service inspection in 1976.
B)
All tube:; containing 1% - 39% wall loss; tubes three rows on either side of the untubed lane; tubes adjacent to plugged, but non-stabilized tubes; and tubes containing previous indications below the threshold of a clear signal were re-inspected.
C)
Tubes with indications below the threshold of a clear signal were inspected by a motorized rotating pancake coil (MRPC) probe, as has been the practice for the past two EC inspect *ons.
D)
FPC pulled 7 tubes from the "B" steam generator.
Chemical and metallurgic analyses will be performed on these tubes in an effort to gather data that will assist in better characterizing freespan indications that are below the threshold of a clear signal. Three of the tubes had degradation of greater than 40 % and would have been plugged (see Table B).
Four tubes would not have required plugging if they have been left in service.
The tubes that were removed from service for metallurgical examination were:
Row / Tube No.
41/44 52/51 90/28 97/91 106/32 109/32 133/33
- Tubes would have been plugged.
EDDY CURRENT TESTING REFORT (PAGE 2 0F 10)
For the repair of the seven pulled tubes, pursuant to 10 CFR 50.55 (a)(g)(iv), FPC used an automatic welding process for steam generator welded plugs developed by Babcock and Wilcox Nuclear Services (BWNS).
This method was developed following the guidance of the 1989 Edition of ASME Section III.
ASME Section XI, 1989 Edition was used for qualification of procedures and personnel.
SELECTION OF SAMPLES AND RESULTS:
The selection of the inspection samples was conducted in accordance with Technical Specification (TS) Table 4.4.2.
The samples size was determined by dividing the total number of tubes to be insoected in each steam generator into seven samples to define the number of tubes constituting "S" and then determine the size of the TS samples 1s, 2s and 4s.
These samples were randomly selected and their inspection results tracked to allow recognition of entry into the three possible TS categories.
The total number of tubes inspected in the A steam generator was 7,961 tubes.
The first sample consisted of 1,122 tubes, two degraded tubes were found in this sample of which one tube was defective and therefore plugged.
The second sample had 2,243 tubes, two degraded tubes were found, both tubes were plugged. The third sample had 4,596 tubes with nine degraded tubes of which five were plugged.
The total number of plugged tubes in the A steam generator was 22, eight pluggers were from the three TS samples, seven pluggers were from special interest areas and seven additional tubes were administratively (indications less than 40 percent through-wall penetration) plugged due to location and type of obser"ed tube degradation.
The first sample for the B steam generator consisted of 891 tubes, four degraded tubes were found of which three were plugged.
The second sample 1,802 tubes with seventeen degraded tubes of which sixteen were plugged.
The third sample had 3,752 tubes with thirty-seven degraded tubes, twenty-three of these tubes were plugged.
The tctal number of tubes plugged in the B steam generator was 46, forty-two tubes were from the three TS samples and four additional tubes were administratively L
(indications less than 40 percent through-wall penetration) plugged due l
to location and tyr 9 of observed tube degradation.
All samples were in the C-2 category requiring no additional inspection i
after the third sample.
However, due to the efficiency of the l
inspection and availability of time and resources, FPC expanded the l
inspection by testing a supplemental sample which included the remaining tubes of the 8 generator that had never been inservice inspected before.
The supplemental inspection included 4,535 tubes; twenty-nine tubes were found degraded; sixteen tubes were plugged.
Tables A and B provide a list of all tubes plugged in cach steam generator and their location.
These tables include tubes found to be defective during the three sample inspections and therefore plugged, and tubes that were administratively plugged.
Table C consists of all plugged tubes from the supplemental inspection of the B steaa generator.
t EDDY CURRENT TESTING REPORT (PAGE 3 0F 10)
CONCLUSION:
FPC has completed a comprehensive inspection of both steam generators.
The inspection encompassed our TS requirements and the supplemental expanded inspection.
The results of these inspections showed no significant rate of degradation or failure mechanisms.
Further understanding of the data obtained is expected once the results of tests to be performed on the seven pulled tubes is available.
g_
y:-
'r ED0Y CURRENT; TESTING REPORT
.(PAGE_40F10).
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TABLE A "A" OTSG NO. ' R0W TUBE IND.
%TW VOLTS -
LOCATION 1.
7 28 WAR 64 0.83 9TH TSP + 0.00" q
WAR 86 0.80 81H TSP + 0.00" 2.
18 39 MBM 0.28 10TH TSP + 28.60" L
3.
26 91 WAR 19 0.24 7TH TSP + 0.59" 4.
27 92 WAR 50 2.67 7TH TSP + 0.00" WAR 42 2.10-8TH TSP + 0.00" 5.
60 114 ODI 50 1.50 14TH TSP + 0.91" 6.
66
-129 WAR 52 0.94 10TH TSP + 0.00" 7.
72 67 001 64 1.50 UTSF + 0.39" 8.
72-128 ODI 46 1.21 8TH TSP -
0.60" L
9.
731 63 SAI 0.27
-UTSF - 0.68" i
-10.
174 30 CCL 0.46 UTSF + 0.11" B.
11, 74 58 CCL 1,53 UTSF + 0.12" l[
- 12.
75 52 MBM 0.21 14TH TSP + 2.53" k3.
75 125 ODI 47 1.20 10TH TSP -
0.69"
- 14.
77 5
WAR 1.67 15TH TSP + 0.40" l
r me.
6 l
1 EDDY CURRENT TESTING REPORT (PAGE50F10)
TABLE A "A" OTSG NO.
R0W TUBE IND.
%TW VOLTS LOCATION 15.
0.92" 0.90 UTSF t 0.18" 16, 77 43 SAI 17, 79 28 CCL 2.90 UTSF -
0.14" 18.
79 30 CCL 2,14 UTSF -
0.11" 19.
79 34 CCL 1.75 UTSF -
0.10" 20, 90 17 ODI 63 1.41 12?H TSP + 0.68" 21.
97 98 MBH 0.67 13TH TSP 4 4.62" 22.
149 25 WAR 37 0.57 10TH TSP -
0.02" i
Tubes were plugged because of crack-like indications and location of defect.
If a WAR or MBM was in an area of concern, (i.e., high steam cross flow) then it was plugged.
WAR - Wear TSP - Tube Support Plate MBM - Manufacturer Burnish Marks 001 - Outside Diameter Indication SAI - Single Axial Indication CCL - Circumferential Crack-Like UTSF - Upper Tube Secondary Face l
l
__________.___A__________._______________
EDDY CURRENT TESTING REPORT (PAGE 6 0F 10)
TABLE B "B" OTSG NO.
R0W TUBE IND.
%TW VOLTS LOCATION 1.
112 39 ODI 50 0.86 LTSF + 6.33" 2.
131 56 001 47 1.26 13TH TSP -
0.83" 3.
143 55 001 55 1.22 7TH iSP + 0.00" 4,
6 14 ODI 43 1.08 9TH TSP + 0.96" 5.
41 41 ODI 42 1.12 LTSF 4 14.07" 6.
44 '
49 ODI 64 0.54 LTSF + 12.82" ODI 61 0.53 LTSF + 3.45" 7,
51 81 ODI 40 1.05 LTSF +
7.25" 8.
52 33 ODI 56 1.77 9TH iSP -
0.56" 9.
63 30 001 40 1.00 LTSF +
7.29" 10.
67 111 ODI 43 1.01 4TH TSP + 0.61" 11.
80 42 DDI 46 0 88 9TH TSP +
5.37" i
l 12.
95 43 ODI 56 1.24 LTSF + 7.04" 13, 93 92 001 67 0.79 LTSF + 10.31" l
l 14.
97 9x ODI 62 0.74 LTSF + 14.28"++
001 76 0.90 LTSF + 8.28"
++ Tube pulled for metailurgical examination.
ED0Y CURRENT TESTING REPORT (PAGE 7 0F 10)
TABLE D "B" OTSG NO.
R0W TVBE IND.
%TW VOLTS LOCATION 15.
103 43 ODI 63 1.16 LTSF : 0.96" 16, 105 55 001 64 0.61 2ND TSP - 0.22" 17.
125 8-WAR 67 2.59 9TH TSP - 0.11" l-WAR 31 1.62 8TH TSP - 0.03" WAR 47 2.23 7TH TSP - 0.00" 18.
143 43 001 54 2.38 7TH TSP - 0.75" 19.
144 29 ODI 55 1.28 7TH TSP - 0.77" 20.
4 41 ODI 49 1.08 12TH TSP - 0.082" 21, 9
55 ODI 53 1.30 9TH TSP - 0.90" 22.
25 9
ODI 73 1.22 15TH TSP + 29.86" ODI 90 1.37 4TH TSP + 21.58" ODI 87 1.27 LTPF + 7.19" 23.
35 46 ODI 52 1.30 7TH TSP - 0.88" 24.
51 39 ODI 66 1.96 LTSF + 7.98" 25, 52 15 001 53 1,59 3RD TSP -
0.77" I
26.
59 32 ODI 70 1.05 LTSF + 15.07" 27.
81 95 001 64 0.53 LTSF + 9.36" 28.
90 28 ODI 46 1.75 LTSF + 7.88"++
29.
93 37 ODI 53 1.18 LTSF + 12.18"
++ Tube pulled for metallurgical examination.
l l
( ' t l-
~
1 EDDY CURRENT TESTING REPORT (PAGE 8 0F 10)
TABLE B "B" OTSG NO.
R0W TUBE IND
%TW VOLTS LOCATION 30.
94 93 001 70 0.73 LTSF + 12.38" 31, 96 46 ODI 49 1.61 7TH TSP - 0.83" 32, 99 91 00!
53 1.12 LTSF + 7.46" 33.
105 33 001 46 1.20 LTSF + 7.52" 34.
105 119 ODI 48 2.24 7TH TSP - 0.84" 35.
107 35 ODI 61 1.13 L1SF + 1!.45" 36.
121 44 001 54 1.29 7TH TSP - 0.77" 37, 130 44 ODI 54 1.16 7TH TSP - 0.82" 38.
138 75 ODI 48 1.47 7TH TSP - 0.73" m
39, 140 62 001 62 1.28 7TH TSP - 0.92" 40.
145 27 WAR 51 1.37 8TH TSP + 0.00" 41.
146 34 001 67 1.33 7TH TSP - 0.89" 42.
133 33 WAR 2.72 7TH TSP - 0.82"++
0.81 UTSF + 0.13" 43.
74 16 SAI 4+ Tube pulled for metallurgicrl examination.
l
EDDY CURRENT TESTING REPORT l
(PAGE 9 0F 10)
TABLE B "B"
OTS N0.
R0W TUBE IND. I%TW VOLTS LOCATION 44.
74 22 MAI 0.37 UTSF - 0.89" 45.
78 13 SAI 0.87 U1SF - 15.96" 40.
78 13 CCL 0.47 UTSF + 0.18" Tubes were plugged because of crack-like indications and location of defect If a WAR or MBH was in an area of concern, (i.e., high steam cross flow) then it was plugged.
WAR - Wear TSP - Tube Support Plate ODI - Outside Diameter Indication LTSF - Lower Tube Secondary Face LTPF - Lower Tube Primary Face SAI - Single Axial Indication MAI - Multiple Axial Indication CCL - Circumferential Crack-Like UTSF - Upper Tube Secondary Face
't EDDY CURRENT TESTING REPORT (PAGE100F10)
TABLE C SUPPLEMENTAL INSPECTION
'B' OTSG NO.
R0W TUBE IND.
%TW VOLTS LOCATION 1.
29 75 ODI 57 3.28 LTSF + 3.04" 2.
44 45 ODI 47 0.90 LTSF + 10.02" 3.
45 50 001 50 0.89 LTSF + 9.11" 4.
50 38 ODI 48 1.10 LTSF + 6.66" 5.
53 40 001 67 0.97 LTSF + 8.03" 6.
54 41 001 75 0.69 LTSF + 10.69" 7,
62 125 ODI 59 0.97 UTSF + 7.19" 8.
69 71 001 59 3.03 7TH TSP -
0.76" 9.
84 35 001 54 1.05 LTSF + 16.26" 10.
86 31 001 56 0.94 LTSF + 10.66" 11.
92 29 ODI 70 0.73 L13F + 25.50" 12.
102 37 ODI 43 0.96 LTSF + 15.26" 001 56 1.38 LTSF + 13.44" 13.
102 78 ODI 51 1.09 3RD TSP - 0.83" 14.
132 47 ODI 54 2.33 7TH TSP -
0.80" 15.
143 29 ODI 48 1.42 7TH TSP -
0.70" 16.
143 45 ODI 63 2.25 7TH TSP -
0.80" TSP - Tube Support Plate l
ODI - Outside Diameter Indication IDI - Inside Diameter Indication LTSF - Lower Tube Secondary f ace UTSF - Up-ar Tube Secondary Face i