ML102250418
| ML102250418 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 07/29/2010 |
| From: | David Bice Entergy Operations |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 1 CAN071003 | |
| Download: ML102250418 (18) | |
Text
"Entergy Entergy Operations, Inc.
1448 S.R. 333 Russellville, AR 72802 Tel 479-858-4710 David B. Bice Acting Manager, Licensing Arkansas Nuclear One 1 CAN071003 July 29, 2010 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555
SUBJECT:
Steam Generator Tube Inspection Report - 1 R22 Arkansas Nuclear One, Unit 1 Docket No. 50-313 License No. DPR-51
Dear Sir or Madam:
Entergy Operations, Inc. (Entergy) inspected the Arkansas Nuclear One, Unit 1 (ANO-1) steam generator (SG) tubes during the Spring (March) 2010 refueling outage (1R22) in accordance with ANO-1 Technical Specification (TS) 5.5.9, Steam Generator Program.
ANO-1 TS 5.6.7, Steam Generator Tube Inspection Reports, requires the results of the in-service inspection to be submitted to the NRC within 180 days after the initial entry into Mode 4. Attached is the subject inspection report.
The 1R22 inspection performed on both SGs involved an initial full-length bobbin coil examination of specific locations near tie rods. The X-probe used consists of an array of coils for diagnostic testing.
This completes the reporting requirements of the ANO-1 TS for this inspection.
This submittal does not include any new commitments.
If you have any questions or require additional information, please contact me.
Sincerely, DBB/rwc Attachments:
1.
2.
3.
ANO-1 Steam Generator Inspection Report - 1 R22 SG "A" Wear Indications - 1 R22 SG "B" Wear Indications - 1 R22 A~cv7
1 CAN071 003 Page 2 of 2 cc:
Mr. Elmo E. Collins Regional Administrator U. S. Nuclear Regulatory Commission Region IV 612 E. Lamar Blvd., Suite 400 Arlington, TX 76011-4125 NRC Senior Resident Inspector Arkansas Nuclear One P. O. Box 310 London, AR 72847 U. S. Nuclear Regulatory Commission Attn: Mr. Kaly Kalyanam MS 0-8 B1 One White Flint North 11555 Rockville Pike Rockville, MD 20852 Mr. Bernard R. Bevill Arkansas Department of Health Radiation Control Section 4815 West Markham Street Slot #30 Little Rock, AR 72205 to 1 CAN071003 ANO-1 Steam Generator Inspection Report 1 R22 to 1 CAN071003 Page 1 of 9 ARKANSAS NUCLEAR ONE, UNIT I STEAM GENERATOR INSPECTION REPORT - 1R22 1
INTRODUCTION Arkansas Nuclear One, Unit 1 (ANO-1) Technical Specification (TS) 5.6.7, Steam Generator Tube Inspection Reports, requires Entergy Operations, Inc. (Entergy) to submit a 180-day report to the NRC that outlines the details of the steam generator (SG) tubing inspections that were performed during the reporting period. The report shall include:
- 1.
The scope of inspections performed on each SG.
- 2.
Active degradation mechanisms found.
- 3.
Nondestructive examination techniques utilized for each degradation mechanism.
- 4.
Location, orientation (if linear), and measured sizes (if available) of service induced indications.
- 5.
Number of tubes plugged during the inspection outage for each active degradation mechanism.
- 6.
Total number and percentage of tubes plugged to date.
- 7.
The results of condition monitoring, including the results of tube pulls and in-situ testing.
The operating period for this report includes one refueling inspection outage (1 R22), in March 2010, a non In-Service Inspection (ISI). This report details the result of that inspection. The inspection was to determine the extent of bowing of the tie rods and not an ASME Code type inspection. Tube support plate wear was justified for two cycles. The extent of bowing was consistent with predictions made in the previous operational-assessment (OA). Also the tubes that contained wear were consistent with the growth rates and estimates predicted in the' previous OA. The degradation identified met all performance criteria.
2 DESIGN The replacement steam generators for ANO-1 are Enhanced Once-Through Steam Generators (EOTSG) manufactured by AREVA. The EOTSG is a straight shell and tube type heat exchanger installed in a vertical position with bottom supports and such emergency supports as required to accommodate normal and accident loads. The tubing consists of Inconel 690 thermally treated tubing that is 5/8" in diameter with a 0.037" wall thickness. The tubes are expanded full-depth hydraulically in the tubesheet. There are 15 tube supports that are constructed of stainless steel (SA 240 type 410) and are a broached trefoil-hole design.
to 1 CAN071003 Page 2 of 9 3
REPORT REQUIREMENTS 3.1 The scope of inspections performed on each SG.
Table 3.1.1 lists the inspection scope of 1 R22.
Table 3.1.1 1R22 Inspection Scope SG "A" Examination Type Bobbin Initial X-Probe/Plus Point SG "B" Bobbin Initial X-Probe/Plus Point TEC Tube End Cold TEH Tube End Hot Inspections Conducted 650 41
% Scope 4
N/A Extent Tested TEC to TEH' N/A 312 0
2.
N/A TEC to TEH N/A 3.2 Active. degradation mechanisms found.
This was the third ISI following replacement of the SGs. The only mechanisms identified were mechanical wear at tube support plates and tie rod / tube bowing. These are listed in Table 3.2.1.
Table 3.2.1 Indication List for 1R22 SG I
"A" "B"
Tube Support Wear 63 21 Proximity 87 0
to 1 CAN071003 Page 3 of 9 Table 3.3.1 Nondestructive examination techniques utilized for each degradation mechanism.
Site-ii 4.SiteY Review~
Technique Site Industry Damage Demonstrated Extended Demed (ET ETSS Qualification Mechanism Applicability Applicability Acceptable
__________Detectior iin c Drill TSP PLP wear Tie rod-to-96004.1, rev 12 1 Bobbin 1
TSP Wear Broach TSP tube wear Yes Yes 96043.1, rev.1 Tube-to-tube wear (if similar morphology)
Expansion 2040X.1, rev.5 transitions, 2 X*Probei 2
2050X.1, rev.4
- ODSCC, freespan, None Yes No PWSCC support (X=0-3) structures, dents ETSS ODSCC PWSCC TSP Examination Technical Specification Sheet Outside Diameter Stress Corrosion Cracking Pure Water Stress Corrosion Cracking Tube Support Plate 3.4 Location, orientation (if linear), and measured sizes (if available) of service induced indications.
The only service-induced mechanism is wear at the tube support plates. Due to the large number of indications, these are listed in Attachments 2 and 3 of this submittal for SG "A" and SG "B", respectively. There were no wear indications associated with proximity tubes.
3.5 Number of tubes plugged during the inspection outage for each active degradation mechanism.
There were no tubes plugged in 1 R22.
3.6 Total number and percentage of tubes plugged to date.
There are no sleeves installed in either generator. The plugging information is listed in Table 3.6.1.
to 1 CAN071003 Page 4 of 9 Table 3.6.1 Cumulative Plugs in Service SG "A" Year 2005 2005 2007 2008 2010 Outage Fabrication Baseline 1 R20 1 R21 1 R22-,
Outage Fabrication Baseline 1 R20 1 R21 1 R22 Installed 2
0 0
8 0
Installed 0
0 1
5 0
Cumulative 2
2 2
10 10 Cumulative 0
0 1
6 6
% Plugged
<0.1
<0.1
<0.1
<0.1
<0.1
% Plugged 0
0
<0.1
<0.1
<0.1 SG "B" Year 2005 2005 2007 2008 2010 Note - 15597 total tubes so 0.1% = 15 tubes 3.7 The results of condition monitoring, including the results of tube pulls and in-situ testing.
All condition monitoring requirements were met. There were no indications that exceeded performance criteria or in-situ screening limits. There were no tube pulls required.
Proximity is an indicator of tube bowing. The bowing resulted from stay rod bowing due to a compressive load applied during cool down from locking of the tube support plates in the upper shroud. This was originally presented to the NRC in a presentation on August 29, 2007.
It was agreed that another inspection would be performed in 1 R22 the next refueling outage) to validate the root cause. The amount of bowing did increase slighty from 1R21 to 1R22, but was in the expected range. SG "A" continues to be the only affected generator and only the Z-axis side. The maximum bow is currently at 1.283" of lateral bow and is located in the first span (area between the lower tubesheet and the first tube support plate) and the outer most circle of rods. Contact with adjacent tubes is limited to the first span. The two most dominant locations are on either side of the Z-axis at Rows 64 and 88. The following are depictions of the condition:
to 1 CAN071003 Page 5 of 9 Figure 3.7.1 Location Row 64 67i 67 67 4 r66 'kj r66 r6*
6"ý r6 6J Figure 3.7.2 Location Row 88 D9 K9ý 89 89 K89" 89 K89 As noted in the above figures, the movement of the tie rod is dependent on its location around the periphery. Figure 3.7.1 shows a rod that more directly impacts the rows of tubes. It should be noted that the two tubes in direction of the bow at these two locations were preventatively plugged and stabilized in the previous outage (1R21).
to 1 CAN071003 Page 6 of 9 Listed below in Tables,3.7.1 and 3.7.2 is the lateral bowing extents by location for the last three outages.
Table 3.7.1 Outer Most Ring Tie Rod Location Bow at 1R20 Bow at 1R21 Bow at 1R22 (Z Axis) 1 st Span Row 12 None Detected None Detected 0.180 1st Span Row 24 0.250 0.691 0.891 1st Span Row 42 0.450 0.726 0.979 1st Span Row 64 0.868 1.158 1.283 Ist Span Row 88 0.748
" 1.025 1.241 1 st Span Row 110 0.484 0.797 1.039 Ist Span Row 128 0.250 0.448 0.559 2"d Span Row 24 None Detected None Detected
<0.05, 2 d Span Row 42 None Detected
<0.14
<0.17 2nd Span Row 64 None Detected None Detected Not Determinable 2nd Span Row 88 None Detected
<0.13 Not Determinable 1 lth Span Row 42 None Detected None Detected
<0.06 1 th Span Row 64 None Detected None Detected Not Determinable 1 lth Span Row 88 None Detected None Detected Not Determinable 1 th Span Row 110 None Detected None Detected
<0.08 1 2 th Span Row 42 None Detected None Detected
<0.05 1 2 th Span Row 64 None Detected None Detected Not Determinable 1 2 th Span Row 88 None Detected None Detected Not Determinable 1 3th Span Row 42 None Detected
<0.07
<0.07 1 3 th Span Row 64 None Detected None Detected Not Determinable 13" Span Row 88 None Detected None Detected Not Determinable 13 th Span Row 128 None Detected None Detected
<0.03 1 4 th Span Row 42 None Detected
<0.14
<0.04 1 4 th Span Row 64 None Detected
<0.13 Not Determinable 1 4 th Span Row 88 None Detected
<0.13 Not Determinable 14 th Span Row 110 None Detected None Detected
<0.08 1 5 th Span Row 24 None Detected
<0.05
<0.04 1 5 th Span Row 42 None Detected
<0.19
<0.16 1 5 th Span Row 64 None Detected
<0.10 Not Determinable 15 th Span Row 88 None Detected
<0.15 Not Determinable 15 th Span Row 110 None Detected
<0.15
<0.09 15 th Span Row 128 None Detected
<0.13
<0.13 to 1 CAN071003 Page 7 of 9 Table 3.7.2 Second Outer Most Ring Tie Rod Location Bow at 1 R20 Bow at 1 R21 Bow at 1 R22 (Z Axis) 1st Span Row 33 None Detected None Detected 0.022 1st Span Row 47 None Detected
<0.50 0.550 1st Span Row 66 0.357 0.559 0.727 1st Span Row 86 0.25 to 0.32
<0.05 0.670 1st Span Row 105 None Detected
<0.05 0.550 2 nd Span Row 47 None Detected None Detected
<0.09 2 nd Span Row 66 None Detected None Detected
<0.10 2 nd Span Row 86 None Detected None Detected
<0.09 2 nd Span Row 105 None Detected None Detected
<0.05 1 3th Span Row 86 None Detected None Detected
<0.03 1 4 th Span Row 86 None Detected
<0.09
<0.06 15th Span Row 86 None Detected
<0.05
<0.04 Tube Support Plate Wear As noted earlier, two cycle operation was justified for the tube support plate wear damage mechanism. During the 1 R22 inspection, tubes that had previous wear indications in the population of tubes tested (around the tie rods and bounding tubes) were sized for wear and a growth rate evaluation was performed. This was compared to the previous cycle OA.
One additional condition that is subject to assessment for both condition monitoring (CM).and OA are the axial loads that result from a postulated Large Break Loss of Coolant Accident (LBLOCA) and its affect on structural and leakage integrity of wear scars. In order to address these conditions, AREVA has performed testing of large depth (90% through wall (TW)) and large circumferential extent (compared to land contact).tapered wear flaws. Tensile testing of these types of flaws was performed and the results indicated that there is very little difference between the ligament pop-through and rupture load for most depths of tapered wear. The test results also clearly show that ligament pop-through will not occur at taper flaw depths up to 90 plus degrees for applied axial loads equivalent to the yield strength of the tube. Therefore, it is concluded that ligament pop-through and leakage of EOTSG Alloy 690 tubing is not a concern for tapered wear flaw depths up to 90% TW when exposed to tube yield strength limiting loads associated with a LBLOCA. Since no wear indications are approaching this severity in either the current inspection, nor with respect to the predicted sizes of wear scars projected out to 1 R23, postulated LBLOCA loads have no affect on tube integrity for CM or OA.
to 1 CAN071003 Page 8 of 9 For a comparison on growth rates, Figure 3.7.3 list the values for both 1R21 and 1R22. On the upper end of the curve (highest growths) it can be seen that the I R22 results are much lower than the 1 R21 results:
Figure 3.7.3 Comparison of Growth Rates Comparison of Growth for Both OTSGs 1
U-0I-0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0
S1R22 Growth 1R21 Growth"
... A 10
-5 05 1'0 15 20 25
%TW/EFPY Table 3.7.3 Previous OA Growth Rate Predictions Maximum NDE Projected Margin Projected Depth Depth Returned Corresponding Depth Using Using 9 5th Region to Service Real Depth 95 h Growth Growth Using Maximum
(% TW)
(% TW)
(% TW)
(% TW)
Growth (% TW)
SGA Zone 1 27.00 27.22 52.50 25.50 72.99 SGA Zone 2 6.00 5.17 30.45 47.55 50.94 SGA Zone 3 14.00 13.57 24.19 53.81 30.45 SGB Zone 1 27.00 27.22 48.34 29.66 69.16 SGB Zone 2 0.00 0.00 21.12 56.88 41.94 SGB Zone 3 19.00 18.82 34.46 43.54 43.42 Zone 1 = Radius > 49 Inches, Elevation > TSP 7 Zone 2 = Radius > 49 Inches, Elevation < TSP 8 Zone 3 = Radius < 49 Inches, All Elevations to 1 CAN071003 Page 9 of 9 The 95th Percentile values for growth by zone are (%TW/EFPY):
SGA Zone 1 = 25.28 SGA Zone 2 = 25.28 SGA Zone 3 = 10.62 SGB Zone 1 = 21.12 SGB Zone 2 = 21.12 SGB Zone 3 = 15.64 The largest growths were in Zone 1 of the area adjacent to the aspirating port. The two largest in SGB were new growths that typically run higher than the repeat wear indications. The largest repeat growths were approximately 7% which is well below the predicted 21 - 25%
values in the OA.
ANO-1 0TSG A TSP Wear Growth Distribution 4A C0 0.
0t 12 10-81 6-o4 m I y S-10
-9
-8 6 -5 3
-2
-1 0
-1R21
- 1R22 1
2 3
4 5
6
- 7.
8 9
10 AChange ANO-10TSG A
TSP Wear Growth Distribution ANO-I OTSG A TSP Wear Growth Distribution C
0 C.
0IL 71 61 51 41 2-
- 11.
0 CO~
0 Co "O-10 8 6 4
-3 1 0
1 2 3
4 5
6 7
8 9
1R21 - 1R22 Change U,
a 0
C-to 1 CAN071003 SG "A" Wear Indications - 1R22 to 1 CAN071003 Page 1 of 3 SG "A" Wear Indications - 1R22 Item #
Row Column
% TW Location Elevation 1
9 31 11 12S
-0.76 2
11 14 14 10S
-0.51 3
11 14 3
12S
-0.54 4
11 15 7
10S
-0.56 5
11 55 6
09S 0.45 6
12 15 5
10S 0.48 7
12 15 9
10S
-0.59 8
13 17 9
09S
-0.59 9
13 57 7
09S
-0.62 10 23 85 22 10S
-0.76 11 23 86 32 10S
-0.87 12 24 38 6
08S 0.48 13 24 83 23 10S
-0.76 14 25 40 4
08S 0.48 15 25 59 11 08S
-0.76 16 31 79 4
08S 0.48 17 32 29 5
08S 0.51 18 32 29 8
08S
-0.54 19 33 29 7
08S
-0.62 20 33 30 5
08S 0.48 21 33 80 7
08S
-0.76 22 46 22 6
08S 0.48 23 46 23 4
08S 0.51 24 46 23 13 08S
-0.61 25 47 21 7
08S
-0.62 26 47 23 7,
08S
-0.59 27 48 22 6
08S
-0.7 28 63 22 5
08S 0.53 29 63 22 10 08S
-0.61 to 1 CAN071003 Page 2 of 3 SG "A" Wear Indications - 1R22 (continued)
Item #
Row Tube
% TW TSP Loc 30 64 22 11 08S
-0.59 31 65 21 15 08S
-0.65 32 65 110 9
07S 0.45 33 65 110 9
09S
-0.64 34 65 110 13 loS 0.28 35 66 21 5
08S
-0.55 36 66 22 12 08S
-0.62 37 67 22 8
08S
-0.65 38 67 23 12 08S
-0.64 39 68 24 5
08S 0.5 40 84 22 7
08S 0.51 41 84 22 19 08S
-0.62 42 84 23 15 08S
-0.59 43 85 23 7
08S 0.52 44 86 22 8
08S 0.52 45 88 22 8
08S
-0.62 46 104 23 4
08S
-0.65 47 104 25 8
08S
-0.65 48 105 24 8
08S
-0.59 49 106 23 6
08S 0.51 50 106 23 12 08S
-0.65 51 106 24 5
08S
-0.59 52 119 30 13 08S
-0.68 53 120 78 8
08S
-0.62 54 120 78 13 08S 0.51 55 127 41
- 7.
08S 0.45 56 127 88 6
09S 0.48 57 128 83 13 09S 0.42 to 1 CAN071003 Page 3 of 3 SG "A" Wear Indications - 1 R22 (continued)
Item #
Row Tube
% TW TSP Loc 58 129 9
18 09S 0.51 59 129 10 5
14S 0.48 60 139 57 11i 09S
-0.59 61 140 16 7
09S
-0.68 62 141 14 10 09S 0.48 63 141 15
.11 09S 0.42 to 1CAN071003 SG "B" Wear Indications - 1R22 to 1 CAN071003 Page 1 of 1 SG "B" Wear Indications - 1 R22 Item #
Row Column
% TW Location Elevation 1
11 14 34 10S
-0.67 2
11 15 27 10S
-0.7 3
12 15 33 10S
-0.78 4
23 38 4
08S 0.48 5
23 56 6
08S 0.48 6
25 41 3
08S
-0.69 7
31 78 9
08S 0.48 8
31 79 4
08S 0.48 9'
32 77 6
08S 0.43 10 65 110 9
10S 0.45 11 66 109 6
08S 0.48 12 86 20 4
08S
-0.74 13 86 20 5
08S 0.48 14 86 109 4
08S 0.5 15 88 122 9
09S 0.42 16 104 99
.7 10S 0.47 17 110 106 6
09S 0.42 18 139 57 6
09S
-0.53 19 140 55 12 13S 0.37 20 141 14 7
12S 0.37 21 141 55 10 11S
-0.74