ML090050027
| ML090050027 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 12/29/2008 |
| From: | Baxter D Duke Energy Carolinas |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 08-ON-002 | |
| Download: ML090050027 (21) | |
Text
I
,Duke DAVE BAXTER Vice President SEnergy.
- Oconee Nuclear Station Duke Energy Corporation December 29, 2008 ON01 VP17800 Rochester Highway Seneca, SC 29672 864-885-4460 864-885-4208 fax, U.S. Nuclear Regulatory Commission dabaxter@dukeenergy.com Attn: Document Control Desk Washington, DC 20555-0001
Subject:
Duke Energy Carolinas, LLC Oconee Nuclear Station, Unit 3 Docket No: 50-287 Fourth Ten Year Inservice Inspection Interval Request for Relief No. 08-ON-002 Pursuant to 10 CFR 50.55a(g)(5)(iii), attached is a Request for Relief from the requirement to examine 100% of the volume specified by the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code),Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components, 1998 Edition with 2000 Addenda (as modified by Code Case N-460).
Request for Relief 08-ON-002 is to allow Duke Energy to take credit for two (2) limited ultrasonic examinations on welds associated with various systems and components described in the attached request. The ultrasonic examination coverage of the subject Unit 3 welds did not meet the 90% examination requirements of Code Case N-460. The obtainable volume coverage for weld examination is indicated on the attached requests.
Achievement of greater examination coverage for these welds is impractical due to piping/valve geometry and interferences. Therefore, Duke Energy requests that the NRC grant relief as authorized under 10 CFR 50.55a(g)(6)(i).
If there are any questions or further information is needed you may contact Corey Gray at (864) 886-6325, Very truly yours,
" Dave Baxter, Site Vice President Enclosure www. duke-energy, com
U. S. Nuclear Regulatory Commission December 29, 2008 Page 2 xc wlatt:
Luis Reyes Region II Administrator U.S. Nuclear Regulatory Commission Atlanta Federal Center 61 Forsyth St., SWW, Suite 23T85 Atlanta, GA 30303 John Stang Project Manager U. S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Washington, D.C. 20555 xc(w/o attch):
Andy Hutto Senior NRC Resident Inspector Oconee Nuclear Station Susan Jenkins Section Manager Division of Waste Management Bureau of Land and Waste Management SC Dept. of Health & Environmental Control 2600 Bull St.
Columbia, SC 29201
Relief Request 08-ON-002 Oconee, Unit 3 Page 1 of 7 Relief Request 08-ON-002 Proposed Relief in Accordance with 10 CFR 50.55a(g)(5)(iii)
Inservice Inspection Impracticality Duke Energy Corporation Oconee Nuclear Station - Unit 3 (EOC-22)
Fourth 10-Year Interval - Inservice Inspection Plan Interval Start Date = 1-2-2005 Interval End Date = 12-16-2014 This Relief Request has two welds for which relief is being sought.
The ID's and Item Numbers/Summary Numbers for the two welds are as follows:
List Number Weld ID Item Number/Summary Number
- 1.
3LP-134-103 C05.011.004
- 2.
3HP-365-9C C05.021.052 Attachment A contains the inspection data for these two welds.
Items in this relief request were examined during February of 2006.
Relief Request 08-ON-002 Oconee, Unit 3 Page 2 of 7 I.
ASME Code Component Affected Weld ID = 3LP-134-103 Item Number/Summary Number = C05.011.004 Low Pressure Injection System Reducer to Valve 3LP-18 Weld I11.
Applicable Code Edition and Addenda
ASME Boiler and Pressure Vessel Code,Section XI - 1998 Edition thru the 2000 Addenda III.
Applicable Code Requirement
Table IWC-2500-1, Examination Category C-F-1 Item Number C5.11 Fig. IWC-2500-7 (a), 100% Volume Coverage of Examination Volume C-D-E-F IV.
Impracticality of Compliance The valve material is SA-351/CF8M cast stainless steel and the reducer material is SA 403/WP304 stainless steel. This weld has a diameter of 10.0 inches and a wall thickness of 1.125 inches.
During the ultrasonic examination of this weld, 37.50% coverage of the required examination volume was obtained. The percentage of coverage represents the aggregate coverage from scans performed on the weld and adjacent base material. The coverage from each scan was as follows: 450 shear wave circumferential scans, both clockwise and counter-clockwise covered 50% of the weld and base material; 600 shear wave scan perpendicular to the weld covered 50% of the weld and base material from one axial direction from the reducer side.
The limitation was caused by the taper on the valve side of the weld which prevented scanning from that side. In order to scan all of the required volume for this weld, the valve would have to be redesigned to allow scanning from both sides of the weld, which is impractical. There were no recordable indications found during the inspection of this weld.
A supplemental scan using a 600 refracted longitudinal wave search unit covered 50% of the weld and adjacent base material from the reducer side perpendicular to the weld. This coverage was not included in the aggregate coverage calculation.
V.
Proposed Alternate Examinations or Testing
Relief Request 08-ON-002 Oconee, Unit 3 Page 3 of 7 Use of radiography (RT) to achieve more coverage has been evaluated and discarded because RT is less sensitive to service induced cracking and has not been subjected to the performance demonstration requirements in a manner similar to the ultrasonic method. While RT could in most cases provide more coverage, the loss of sensitivity and lack of performance demonstration militates against its use.
VI.
Implementation Schedule and Duration This request is for the duration of the fourth inservice inspection interval, currently scheduled to end on December 16, 2014.
VII.
Justification for Granting Relief Ultrasonic examination of the weld for the item number 005.011.004 was conducted using personnel, equipment and procedures qualified in accordance with ASME Section XI, Appendix VIII Supplement 2 of the 1998 Edition with the 2000 Addenda as -administered by the PDI. In addition to the volumetric examination with limited coverage, Duke performed a surface examination (code required) on the C05.011 item and achieved 100% coverage. The result from the surface examination was acceptable.
In addition to the 005.011 weld that relief is being requested for limited volume coverage, there was 1 additional 005.011 weld that surface and volumetric examinations were performed on. The examinations didn't identify any recordable indications and 100% coverage was obtained on each of them. The additional weld was from the same system as the 005.011 weld of this request.
The examination and result of the additional weld contributes to the reasonable assurance of pressure boundary integrity for this system piping.
Duke does not claim credit for coverage of the far side of austenitic welds. The
-characteristics of austenitic weld metal attenuate and distort the sound beam when shear waves pass through the weld. Refracted longitudinal waves provide better penetration, but cannot be used beyond the first path leg. Duke uses a combination of shear waves and longitudinal waves to examine single sided austenitic welds when the nominal material thickness exceeds 0.5 inch. A supplemental 600 refracted longitudinal wave is used to interrogate the far side of the weld when the nominal material thickness is greater than 0.5 inch.
However, cove6rage from this supplemental scan is not included in the aggregate coverage calculation.
Duke will use Class 2, Examination Category C-H, pressure testing and VT-2 visual examination to compliment the limited examination coverage. The Code requires that a pressure test be performed once each period for Class 2 items.
Relief Request 08-ON-002 Oconee, Unit 3 Page 4 of 7 This test requires a VT-2 visual examination for evidence of leakage. This testing contributes to the reasonable assurance of pressure boundary integrity. A pressure test and VT-2 exam were performed during May of 2006 (first period of the fourth interval) and no leakage was found for this segment of piping.
In addition to the above Code required examinations (volumetric, surface, and pressure test), there are other activities which provide confidence that, in the event leakage did occur through this weld, it would be detected. Specifically, visual observations performed during operator rounds provide additional assurance that any leakage would be detected prior to gross failure of the component.
The weld/component was inspected by volumetric NDE methods during construction and verified to be free from unacceptable fabrication defects.
Based on the coverage and results of the required volumetric, surface, and pressure testing (VT-2) examinations performed and the operator rounds, it is Duke's position that a reasonable assurance of quality and safety exists.
Relief Request 08-ON-002 Oconee, Unit 3 Page 5 of 7
- 1.
ASME Code Component Affected Weld ID = 3HP-365-9C Item Number/Summary Number = C05.021.052 High Pressure Injection System Tee to Pipe Weld Ih.
Applicable Code Edition and Addenda
ASME Boiler and Pressure Vessel Code,Section XI - 1998 Edition thru the 2000 Addenda III.
Applicable Code Requirement
Table IWC-2500-1, Examination Category C-F-1 Item Number C5.21 Fig. IWC-2500-7(a), 100% Volume Coverage of Examination Volume C-D-E-F IV.
Impracticality of Compliance The tee material is SA 403/WP304 or WP316 stainless steel and the pipe material is SA 376/TP 304 or TP316 stainless steel seamless pipe. This weld has a diameter of 4.0 inches and a wall thickness of.674 inches.
During the ultrasonic examination of this weld, 89.40% coverage of the required examination volume was obtained. The percentage of coverage represents the aggregate coverage from scans performed on the weld and adjacent base material. The coverage from each scan was as follows: 450 shear wave circumferential scans, both clockwise and counter-clockwise covered 100% of the weld and base material; 600 shear wave scan perpendicular to the weld from the pipe side covered 85.80% of the weld and base material from one axial direction. A 600 shear wave scan perpendicular to the weld from the tee side of the weld covered 71.60% of the weld and base material.
The limitation was caused by the radius on the tee side of the weld which obstructed scanning for 4 inches from that side. In order to scan all of the required volume for this weld, the tee would have to be redesigned to allow scanning from both sides of the weld for 3600, which is impractical. There were no recordable indications found during the inspection of this weld.
A supplemental scan using a 600 refracted longitudinal wave from the pipe side covered 14.2% of the examination volume in the obstructed area. This coverage was not included in the aggregate coverage calculation.
V.
Proposed Alternate Examinations or Testing
Relief Request 08-ON-002 Oconee, Unit 3 Page 6 of 7 Use of radiography (RT) to achieve more coverage has been evaluated and discarded because RT is less sensitive to service induced cracking and has not been subjected to the performance demonstration requirements in a manner similar to the ultrasonic method. While RT could in most cases provide more coverage, the loss of sensitivity and lack of performance demonstration militates against its use.
VI.
Implementation Schedule and Duration This request is for the duration of the fourth inservice inspection interval, currently scheduled to end on December 16, 2014.
VII.
Justification for Grantinq Relief Ultrasonic examination of the weld for the item number C05.021.052 was conducted using personnel, equipment and procedures qualified in accordance with ASME Section XI, Appendix VIII Supplement 2 of the 1998 Edition with the 2000 Addenda as administered by the PDI. In addition to the volumetric examination with limited coverage, Duke performed a surface examination (code required) on this C05.021 item and achieved 100% coverage. The result from the surface examination was acceptable.
In addition to the C05.021 weld that relief is being requested for limited volume coverage, there were 10 additional C05.021 welds that surface and volumetric examinations were performed on. The examinations didn't identify any reportable indications and 100% coverage was obtained on each of them. The 10 additional welds were from the same system as the C05.021 weld of this request. The examination and results of the 10 additional welds contributes to the reasonable assurance of pressure boundary integrity for this system piping.
Duke does not claim credit for coverage of the far side of austenitic welds. The characteristics of austenitic weld metal attenuate and distort the sound beam when shear waves pass through the weld. Refracted longitudinal waves provide better penetration, but cannot be used beyond the-first path leg. Duke uses a combination of shear waves and longitudinal waves to examine single sided austenitic welds when the nominal material thickness exceeds 0.5 inch. A supplemental 600 refracted longitudinal wave is used to interrogate the far side of the weld when the nominal material thickness is greater than 0.5 inch.
However, coverage for this supplemental scan is not included in the aggregate coverage calculation.
Duke will use Class 2, Examination Category C-H, pressure testing and VT-2 visual examination to compliment the limited examination coverage. The Code requires that a pressure test be performed once each period for Class 2 items.
Relief Request 08-ON-002 Oconee, Unit 3 Page 7 of 7 This test requires a VT-2 visual examination for evidence of leakage. This testing contributes to the reasonable assurance of pressure boundary integrity.
A pressure test and VT-2 exam were performed during May of 2006 (first period of the fourth interval) and no leakage was found for this segment of piping.
In addition to the above Code required examinations (volumetric, surface, and pressure test), there are other activities which provide confidence that, in the event leakage did occur through this weld, it would be detected. Specifically, operations performs a daily leakage calculation to assure system leak rate limitations imposed by Technical Specifications 3.4.13, "Reactor Coolant System Leakage" are not exceeded. Operations also conducts rounds during which evidence of leakage would be detected prior to gross failure of the component.
The weld/component was inspected by volumetric NDE methods during construction and verified to be free from unacceptable fabrication defects.
Based on the coverage and results of the required volumetric, surface, and the pressure testing (VT-2) examinations performed and the other activities, it is Duke's position that a reasonable assurance of quality and safety exists.
REQUEST RELIEF 08-ON-002 ATTACHMENT A Total Number of Pages = 11 Pages 1-4 are for weld 3LP-134-103 (C05.011.004)
Pages 5-9 are for weld 3HP-365-9C (C05.021.052)
Page 10 is a limitation summary for weld 3LP-134-103 (C05.011.004)
Page 11 is a limitation summary for weld 3HP-365-9C (C05.021.052)
Mkot f W-E-1-Amm-UT Pipe Wa.i Examination Site/Unit: Oconee /
Summary No.:
Co Workscope:
3 5.011.004 IS1 Procedure:
Procedure Rev.:
Work Order No.:
NDE-600 16 98737379 Outage No.:
ONS3-22 Report No.:
UT-06-010 Page:
1 of Y.,
i, Code:
1998 thru 2000 Addenda Cat./Item:
C-F-1/C5.11.4 Location:
Drawing No.:
==
Description:==
Pipe to Valve 3LP-18 System ID:
53A Component ID: C05.011.004 /3LP-134-103 Size/Length:
N/A Thickness/Diameter:
1.125 / 10.0 Limitations:
Yes - See Attached Limitation Report Start Time:
1328 Finish Time:
1342 Examination Surface:
Inside Outside 1-iv Surface Condition: GROUND Lo Location:
9.1.1.1 Wo Location:
Centerline of Weld Couplant:
ULTRAGEL If Batch No.:
03125 Temp. Tool Mfg.:
FISHER Serial No.:
MCNDE32770 Surface Temp.:
76 OF Cal. Report No.:
CAL-06-029, CAL-06-030, CAL-06-031 Angle Used b
45 145T 60 60L I
Scanning dB 30.3 43 48 Indication(s):
Yes:
No !vI Scan Coverage:
Upstream :V.
Downstream 'v'I CW V' CCW IVl Comments:
FC 05-08 Results:
Accept iA/1 Reject!
Info Percent Of Coverage Obtained > 90%:
No - 3 7*5 X Reviewed Previous Data:
Yes Examiner Level 11 i,
Date Revie.er Signature Date Leeper, Winfred C.
2/2/2006
/.J*,
A N
a O6 Examiner Level Il-N S" a"lure Date Site Review Signature Date Griebel, David M.
2/2/2006 N/A Other Level N/A Signature Date ANII Reve Signature Date N/A rI -,
2+/-+1 0
-DUKE POWER COMPANY ISI LIMITATION REPORT Component/Weld ID:
3LP-134-103 Item No:
C05.011.004 remarks:
I NO SCAN SURFACE BEAM DIRECTION Due to Valve to Reducer l
LIMITED SCAN Z
1 E-2 1
Z 2
Z cw Z
ccw Configuration FROM L to L INCHES FROM WO CL to Beyond ANGLE:
Z 0 Z 45 Z 60 other FROM DEG to DEG El NO SCAN SURFACE BEAM DIRECTION DLIMITED SCAN i-1
-2 iI 1
[-
2 cw
[-1 ccw FROM L to L INCHES FROM WO to ANGLE:
E] 0 El 45 El 60 other FROM DEG to DEG El NO SCAN SURFACE BEAM DIRECTION El LIMITED SCAN El1 i 2
El 1 0
2 [] cw Elccw FROM L to L INCHES FROM WO to ANGLE:
El 0 El 45
-- 60 other FROM DEG to DEG
-I NO SCAN SURFACE BEAM DIRECTION
'LIMITED SCAN l1
[] 2 E l 2Elcw
-ccw FROM L to L INCHES FROM WO to Sketch(s) attached ANGLE:
El 0 El 45 El 60 other FROM DEG to DEG Z
yes El No Prepared By:
Winfred Leeper
,vel:
11 Date:
02-02-2006 Sheet of Reviewed By:
Da b:
Authoried Ins
- Date, Daek
3D. /'1 Item No. C05.011.004 Weld No. 3LP-134-103 Coverage Claimed = 50%
No Coverage Claimed Supplemental coverage with 600 RL Wave Only See Note:
Scale: 1"V= 1" Note: 60'RL scan not included in percentage coverage due to requirements of 10CFR50.55a(b)(2)(xv)(A)(2). Best effort scan with 60°RL obtained 50% coverage in one axial direction.
Pipe 0 = 10.75 "t" =
1.1 1/3 "t" -
0.37 Weld Length =
Weld + 1/4" ea. Si Valve = Surface 1 Red. = Surface 2 Total Weld Volume
= (Weld + 1/4" ea. Side) x 1/3 't" x Weld Length
=
21.26 in 3 de =
33.8 1.70 Aggregate Covera.c.e Calculation
$1 = Volve S2 = Reducer S3 = CW
$4 = CCW Total =
Inspector / Date:
0%
50 %
50 %
50%
150 4 =
(0% of the Length x 0% of the Volume )
(100% of the Length x 50% of the Volume)
(100% of the Length x 50% of the Volume)
(100% of the Length x 50% of the Volume) 37.5%/
Aggregate Coverage 7-1 ý, 1 0(-
YI +-1 -11 "U
LIMITED EXAMINATION COVERAGE CHECKLIST ISI Summary No:
C-Ds. n It. CC) 19 Verify search unit wedge index to nose dimension; L/'A Draw the examination volume showing beam paths and obstructions including dimensions;
[',
Note the scale of the drawing; Calculate coverage in a detailed and orderly method; Complete "Limitation Work Shee 'and "Supplemental Report".
RWS1fDE Level III Da te Z
Date QATS NDE Level Jl
/ct4 Date c
Site/Unit: Oconee /
3 Summary No.:
C05.021.052 Workscope:
ISl UT Pipe We.u Examination Procedure:
Procedure Rev.:
Work Order No.:
NDE-600 16 98737763 Outage No.:
ONS3-22 Report No.:
UT-06-011 Page:
1 of Code:
1998 thru 2000 Addenda Cat./Item:
C-F-1/C5.21.52 Location:
Drawing No.:
==
Description:==
Tee to Pipe System ID:
51A Component ID: C05.021.052 /3HP-365-9C Size/Length:
N/A Thickness/Diameter:
.674 / 4.0 Limitations:
Yes-See Attached Limitation Report Start Time:
1330 Finish Time:
1405 Examination Surface:
Inside Outside li,-
Surface Condition: GROUND Lo Location:
9.1.1.2 Wo Location:
Centerline of Weld Couplant:
ULTRAGEL II Batch No.:
03125 Temp. Tool Mfg.:
FISHER Serial No.:
MCNDE32770 Surface Temp.:
73 OF Cal. Report No.:
CAL-06-032, CAL-06-033, CAL-06-034 Angle Used 0
45 45T 60 38 60L Scanning dB 46 43 51 Indication(s):
Yes i No.,;
Scan Coverage:
Upstream v' Downstream v; CW ;I' CCW 'vi Comments:
FC 05-08 Results:
Accept v; Reject Info Percent Of Coverage Obtained > 90%:
q/'
Reviewed Previous Data:
Yes
'I,' -
Item No. C05.021.052 Weld No. 3HP-365-9C E0F I I 600 RLWave 600 Shear Pipe S2 Coverage Claimed = 50%
Te S1 Scale: 1V= 1" No Coverage Claimed Supplemental coverage with 60' RL Wave Only See Note:
Note: 600 RL scan not included in percentage coverage due to requirements of 10CFR50.55a(b)(2)(xv)(A)(l). Best effort scan with 600 RL obtained 50% coverage in one axial direction.
Plan View - Not to Scale Weld 3HP-365-9C Surf. 2 Limited Area Surf. I
/
Side View - Not to Scale Limited 2" on ea. side of Tee in throat area for a total of 4". From Lo + 3" to 5" and from Lo + 10.2" to 12.2" on rface 1.
nspector / Date" Z (X o Page 7I of 5 I
7 +-//
DUKE POWER COMPANY ISI LIMITATION REPORT Component/Weld ID:
3HP-365-9C Item No:
C05.021.052 remarks:
El NO SCAN SURFACE BEAM DIRECTION Limitation Due to Tee
[
LIMITED SCAN
[
1
[-
2 E-1
[
2
-- cw [-
ccw Configuration.
FROM L 3.0" to L 5.0" INCHES FROM WO CL to
.4" ANGLE:
E- 0 El 45 Z 60 other FROM DEG to DEG El NO SCAN SURFACE BEAM DIRECTION ZLIMITED SCAN
[
1 E-2 E-]
1 M 2 cw E] ccw FROM L 10.2" to L 12.2" INCHES FROM WO CL to
.4" ANGLE:
E] 0 [] 45 Z 60 other FROM DEG to DEG E-NO SCAN SURFACE BEAM DIRECTION El LIMITED SCAN
-1
] 2
[-1 1
0 2
E] cw El cow FROM L to L INCHES FROM WO to ANGLE:
El 0 E-l 45 El 60 other FROM DEG to DEG El NO SCAN El LIMITED SCAN SURFACE BEAM DIRECTION
[1l
[: E2 El1
[--
2
[:1 cw
[l ccw FROM L to L INCHES FROM WO to ANGLE:
El 0 El 45 El 60 other FROM DEG to DEG Sketch(s) attached 7'
yes El No Prepared By:
B. Dale Jolly Date:
02-02-2006 Sheet,25 of,,
By:
)ate:
Authorized Inspect Date:~*
'2 -/.3-7-/
WlNo II Weld No. :3HP-365-9C 4
Item No.: C05.021.052
% Coverage Calculations Pipe 0 = 4.5 1=
0.674 1/3 "t" =
0.23 Weld Length =
14.1 Weld + 1/4" ea. Side = 1.30 Length of Obstucted Area = 4.00 Total Weld Volume 100%
= (Weld + 1/4" ea. Side) x 1/3 "t" x Weld Length
=
4.22 in 3
% of Length not Examined 100%
= (Length of Obstucted Area) -- (Weld Length) x 100 28.4 %
% of Length Examined 100%
= 100% - % not Examined
=
71.6%
Axial Coverage from S2 - Pipe 0% of Volume Examined 100% + 50% of Obstructed Volume
=
371.6
-+
14.2
=
85.8%
Axial Coverage from Si - Tee
= 100% of the Volume - % of the Volume not Examined S
100 28.4
=
71.6%
Circumferential Coverage from S3 & S4 both CW & CCW
= 100% of the Volume
=
100 %
Ag-gregafe % of Coveraqe
(S1 +S2+$3+S4)÷+ 4
89.4 % Coverage kim A('10i(-
Page.Lýof Inspector I Date:
LIMITED EXAMINATION COVERAGE CHECKLIST IS Surmmary No:
C.os. oil *olz ED" Verify search unit wedge index to nose dimension; Draw the examination volume showing beam paths and obstructions including dimensions; 12" Note the scale of the drawing; Calculate coverage in a detailed and orderly method; 11A Complete "Limitation Work Sheet" a d "Supplemental Report".
]WS NDE Level III Date "2,o, QATS NDE Level IIllr
(ýa
/ý
1 0 111,,52-1 C) --t I I C05.011.004 3LP-134-103 Primar A.ge BWeld Length Percent of Volume Percent of Scanned (in.)
Covered Coverage Claimed 60' shear Axial Pipe Side 33.77 50 50 No axial scan from the valve side 450 shear sides 33.77 50 50 Counter clockwise 3377 0
50 450 shear both sides Aggregate =37.5 %
Percent of Percent of Supplementary Beam Weld Length Volue C
Percent Actual Angle Direction Scanned (in.)
Covered Claimed Coverage 600 RL Axial pipe Side 33.77 50 0
50
C05.021.052 3HP-365-9C