ML20048A006
| ML20048A006 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 02/11/2020 |
| From: | Mark D. Sartain Dominion Energy Nuclear Connecticut |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 19-386 | |
| Download: ML20048A006 (33) | |
Text
Dominion Energy Nuclear Connecticut, Inc.
5000 Dominion Boulevard, Glen Allen, VA 23060 Dominion Energy.com February 11, 2020 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 DOMINION ENERGY NUCLEAR CONNECTICUT, INC.
MILLSTONE POWER STATION UNIT 2 ASME SECTION XI INSERVICE INSPECTION PROGRAM
Dominion
Energy Serial No.
NRA/SS Docket No.
License No.19-386 RO 50--336 DPR-65 RELIEF REQUESTS FOR LIMITED COVERAGE EXAMINATIONS PERFORMED IN THE SECOND PERIOD OF THE FOURTH 10-YEAR INSPECTION INTERVAL The Millstone Power Station Unit 2 (MPS2) fourth 10-year interval for the inservice inspection program began on April 1, 2010. During the second inspection period of this interval, the components identified in Attachments 1 through 3 received less than the required examination coverage.
Accordingly, pursuant to 10 CFR 50.55a(g)(5)(iii),
Dominion Energy Nuclear Connecticut, Inc. requests relief on the basis that the required examination coverage was impractical due to physical obstructions and limitations imposed by design, geometry and materials of construction of the subject components.
Attachments 1 through 3 contain the specific relief requests and the individual basis for each request. These relief requests have been reviewed and approved by the station's Facility Safety Review Committee.
If you have any questions or require additional information, please contact Shayan Sinha at (804) 273-4687.
Sincerely, Mark D. Sartain Vice President - Nuclear Engineering & Fleet Support
Attachments:
Serial No.19-386 Docket No. 50-336 Page 2 of 2
- 1. Relief Request RR-04 Examination Category B-D, Full Penetration Welded Nozzles in Vessels - Inspection Program B.
- 2. Relief Request RR-04-29, Examination Category C-B, Pressure Retaining Nozzle Welds in Vessels.
- 3. Relief Request RR-04-30, Examination Category R-A, Risk Informed Piping Examinations.
Commitments made in this letter: None cc:
U.S. Nuclear Regulatory Commission Region I 2100 Renaissance Blvd, Suite 100 King of Prussia, PA 19406-2713 R. V. Guzman Senior Project Manager U.S. Nuclear Regulatory Commission One White Flint North, Mail Stop 08-C 2 11555 Rockville Pike Rockville, MD 20852-2738 NRC Senior Resident Inspector Millstone Power Station
ATTACHMENT 1 RELIEF REQUEST RR-04-28 EXAMINATION CATEGORY B-D Serial No.19-386 Docket No. 50-336 FULL PENETRATION WELDED NOZZLES IN VESSELS INSPECTION PROGRAM B DOMINION ENERGY NUCLEAR CONNECTICUT, INC.
MILLSTONE POWER STATION UNIT 2
10 CFR 50.55a Request Number: RR-04-28 Relief Requested In Accordance with 10 CFR 50.55a(g)(5)(iii)
In-service Inspection Impracticality
- 1. ASME Code Components Affected:
ASME Code Class:
Code Class 1 Serial No.19-386 Docket No. 50-336, Page 1 of 7 Examination Category:
B-D, Full Penetration Welded Nozzles in Vessels -
Inspection Program B Item Numbers:
B3.130, Steam Generator (Primary Side), Nozzle-to Vessel Welds Component Identification:
Listed in Table 1 Material:
SA508, CL3 Carbon Steel with Internal Stainless Steel Cladding
- 2. Applicable Code Addition and Addenda ASME Section XI, 2004 Edition, No Addenda
3. Applicable Code Requirement
ASME Section XI, 2004 Edition, Examination Category B-D requires volumetric examination of 100 percent (%) of the weld volume as defined in Table IWB-2500-1 and shown in Figure IWB-2500-7. The alternative requirements of ASME Section XI, Code Case N-460, approved for use in Regulatory Guide 1.147, Revision 18, allows credit for essentially 100% coverage of the welds provided greater than 90%
of the required volume has been examined.
4. Impracticality of Compliance
Pursuant to 10 CFR 50.55a(g)(5)(iii), relief is requested from the 100% volumetric examination coverage requirement of the subject welds due to the geometric configuration which limit the volumetric coverage that can be obtained.
The subject steam generator nozzle-to-vessel welds were examined with a manual ultrasonic technique using equipment and procedures written in accordance with ASME Section XI, Appendix 1 and Section V, Article 4 to achieve the maximum examination coverage practical.
Limitations imposed by the nozzle configuration
Serial No.19-386 Docket No. 50-336, Page 2 of 7 preclude obtaining 100% coverage.
This configuration with the nozzle outside radius within close proximity of the weld prevents complete scanning in these areas due to lift-off of the search unit that occurs causing a loss of contact between the search unit and the component.
The required examination volume of these welds was interrogated ultrasonically to the maximum extent possible. No alternative techniques or advanced technologies were considered capable of obtaining complete coverage of the examination volume.
Isometric drawing and coverage calculations are provided in this attachment.
TABLE 1-Examination Category B-D Welds with Limited Volumetric Coverage
.([ ioi!"1#fil$&l%&,.N:g',,JQJfigi( '!
W }y; z Ig1 ?
J l.;lf;.)tl1/4l*\\+l SG-1-NH-2-A SG-1-NH-4-A SG-1-NH-5-A 30" Cold Leg B3.130 Nozzle to Hemisphere 42'1 Hot Leg B3.130 Nozzle to Hemisphere 30" Cold Leg B3.130 Nozzle to Hemisphere
5. Burden Caused by Compliance
0° Long Wave 30° Shear Wave 45° Shear Wave 60° Shear Wave 0° Long Wave 30° Shear Wave 45° Shear Wave 60° Shear Wave 0° Long Wave 30° Shear Wave 45° Shear Wave 60° Shear Wave Scan limitations due to configuration of the nozzle. No recordable indications were detected.
Scan limitations due to configuration of the nozzle. No recordable indications were detected.
Scan limitations due to configuration of the nozzle. No recordable indications were detected.
72.4%
72.5%
72.4%
To increase examination coverage on the subject welds would require a significant design modification or replacement of components with a different design to
Serial No.19-386 Docket No. 50-336, Page 3 of 7 eliminate the noted obstructions.
This is considered impractical due to cost, increased radiation exposure, and impact to plant equipment.
6. Proposed Alternative and Basis for Use
The subject welds received a volumetric examination to the maximum extent practical. Additionally, these components are monitored for through-wall leakage as part of the ASME Section XI System Pressure Test Program and receive a visual (VT-2) examination at the end of each refueling outage during the system leakage tests required by Section XI, Table IWB-2500-1, Category B-P for class 1 components.
Based upon the examination volumes that were obtained with acceptable results along with the visual (VT-2) examination performed each refueling outage, it is reasonable to conclude that service-induced degradation would be detected.
Therefore, these proposed alternatives will provide an acceptable level of quality and safety by providing reasonable assurance of structural integrity of the subject welds.
7. Duration of Proposed Alternative
The relief is requested for the fourth ten-year inspection interval for Millstone Power Station Unit 2, which began on April 1, 2010 and will end March 31, 2020.
- 8. Precedent A similar relief request was approved for use at MPS2 during the first period of the fourth 10-year ISi interval (i.e., Relief Request RR-04-17 (ADAMS Accession No. ML16172A135)).
1 SG* 1* IR-4*A SG-l*BI-IC*2-A.
$G\\*1*6*:l*A F.lO¬iilJIEJ FO_RMEel.Y C""'46<J<JT1e>tJE"..i..wEeJ21NG, C::.-/c;,>la Ec/JE'lJ*""l*o04-
/
/
I I
I I
I I
ZOf..Jf f-3 REDl<t.W Ft'OM '22-*'29°:Z? S+/-. "3,
!<EV. 1, TO k!E'PRb5G!JJT,J.;:w '5it"A.M 6ENE0l.TOI<' la,Pt.ACG"l²³i l<i'J2.
lt[VISIONS OUfUNC CONSTTION 1, A I,..
A I NORTHEAST UTILITIES SERVICE co.
1--+-+-f---..l.------l-l--l-...j.....1 1111>' ""='AC1' >lJaf.1.1?_ e;.e,.,,y Co.
oi 0
- r
- 3 CD 2? (/)
0
m.
-Uzz Ill O 0 co.
CD CJ1 _,_
,1:s.O<O oww
-+, (,) 0)
-..J 0) 0)
30° USWeld 4.5289" 58.6%
I I
, A A ngle axial direction ase metal exam l.9103" = 94.1%
,. ngle CW/CCW ase metal exam 9.1707" = 56.5%
0°DS Weld 7.7322" = 100%
45°USWeld 2.8460" = 36.8%
fTT7145° DS Weld 7.5277" = 97.4%
60° USWeld 1.7311" = 22.4%
0° DSWeld
.0549" = 65.4%
Weld ID: SG-1-NH-2-A S.S4 S.49 l.lS l.lO S.47 l.l2 l.3S 4.37 4,70 "7
Total Code Exam Volume 7 "' ' v 7 7 7..., essel = 16.9030" n
2 eld = 7.7322" ozzle = 17.0054" otal = 41.6406" 0 exam area 6.9827" = 64.8%
Coverage Total:
0° Subtotal:
0°= 64.8%
Weld Subtotal:
us 30° = 58.6%
DS 30°= 100%
us 45° = 36.8%
DS 45° = 97.4%
us 60° = 22.4%
DS 60° = 65.4%
30° cw= 100%
30° ccw = 100%
45°CW= 100%
45° CCW = I 00%
Total= 780.6 / 10 = 78.1%
Base metal Subtotal:
Axial 30° / 45° / 6 0° = 94.1%
Circ umferential 30° / 45° = 56.5%
Total= 150.6 / 2 = 75.3%
Coverage Total:
64.8 + 78.l + 75.3 = 217.2 I 3 = 72.4%
Scale 1:6 Area dimensions detennined with TurboCad 19 m
C)
- J" CD (/)
- J 0 CD A ::!.
_.. CD !ll
-Ozz m o o co..
CD 01 _..
(Jl O <.O I
I 0 (;J (;J
-+, (;J CXJ
-...J 0) 0)
30DSWeld f
4.6533" - 44.8% "
\\}
I j
x Angle a'lial direction ase metal exam 5.7198" = 90.8%
I);
ngle CW/CCW ase metal exam 8.7921" = 57.2%
45 DS Weldg r777]45 US Weld 2.8646"=27.6% h V //110.3817"= 100%
60DSWeldi 1.6915" = 16.3% j OUS Weld 10.3817" = 100%
6.52 6.62 6.6S 6,6! 6,70S 6.69 6.70 6.S6 6.19 S.95 FIOW' 0klmnopqTotal Code Exam Vol ume 7 1 ' ' 0
' L -essel = 25.5760" r-,
eld= 10.3817" ozzle = 24.7578" otal = 60.7155" exam area 9.2313" = 64.6%
Coverage Total:
0° Subtotal:
0°=64.6%
Weld Subtotal:
DS 30° = 44.8%
us 30°= 100%
DS 45° = 27.6%
us 45°= 100%
DS 60° = 16.3%
us 60°= 100%
cw30°= 100%
CCW 30° = I 00%
cw 45°= 100%
ccw 45° = 100%
Total= 788.7 /IO= 78.9%
Base metal Subtotal:
Axial 30° / 45° / 60° = 90.8%
Cir c umferential 30° / 45° = 57.2%
Total= 148 / 2 = 74%
Coverage Total:
64.6 + 78.9 + 74 = 217.5 / 3 = 72.5%
Scale 1:6 Area dimensions determined with T urboCad 19 Weld ID: SG-1-NH-4-A
oi
()
- T
- 3 CD (/)
- J O CD =
- m.
-Ozz OJ O 0
((l.
CD u, _.
0)0(0 I
I o ww
-+, w (X)
--i 0) 0)
30° USWeld b
4.5289" - 58.6%
c
, A A angle axial direction ase metal exam 1.9103" = 94.1%
Weld ID: SG-1-NH-5-A S.S4 S.49 S.SS 5.50 S.47 5.52 S.38 4.87 hgle CW/CCW v,r-
\\i/.,1'j./1/"k / _,,;:;;- Coverage Total:
ase metal exam I / l 19.1707" = 56.5%
130° DS Weld 7.7322" = 100%
7?--r-.,.......---op_,.._ Total Code Exam Vol ume 7.11' ' v 7 7 7-,_ -essel = 16.9030" n
2 eld = 7.7322" ozzle = 17.0054" otal = 41.6406" 0 exam area 6.9827" = 64.8%
0° Subtotal:
0°=64.8%
Weld Subtotal:
us 30° = 58.6%
DS 30°= 100%
us 45° = 36.8%
DS 45° = 97.4%
us 60° = 22.4%
DS 60° = 65.4%
30° CW= 100%
30° ccw = 100%
45° CW= 100%
45° ccw = 100%
45° USWeldd 2.8460" = 36.8%
e rT'77145° DS Weld 7.5277" = 97.4%
Total= 780.6 / 10 = 78.1%
Base metal Subtotal:
60° USWeldf 1.7311"=22.4% g m0° DSWeld n
.0549" = 65.4%
Axial 30° / 45° / 6 0° = 94.1%
Circ umferential 30° / 45° = 56.5%
Total= 150.6 I 2 = 75.3%
Coverage Total:
64.8 + 78.1 + 75.3 = 217.2 I 3 = 72.4%
Scale 1:6 Area dimensions determined with T urboCad 19 Ol
(')
- J'"
(D (/)
- J (') (D
- ::!.
- m. e!..
-Ozz Ol O 0 co.
(D c.n....>.
-..J O CO I
I 0 uJ uJ
-wco
-..J CJ) CJ)
ATTACHMENT 2 Serial No.19-386 Docket No. 50-336 RELIEF REQUEST RR-04-29 EXAMINATION CATEGORY C-8 PRESSURE RETAINING NOZZLE WELDS IN VESSELS DOMINION ENERGY NUCLEAR CONNECTICUT, INC.
MILLSTONE POWER STATION UNIT 2
Serial No.19-386 Docket No. 50-336, Page 1 of 8 10 CFR 50.55a Request Number: RR-04-29 Relief Requested In Accordance with 10 CFR 50.55a(g)(5)(iii)
In-service Inspection Impracticality
- 1. ASME Code Components Affected:
ASME Code Class:
Code Class 2 Examination Category:
C-B, Pressure Retaining Nozzle Welds in Vessels Item Numbers:
C2.21, Nozzle-to-Shell (Nozzle-to-Head or Nozzle-to-Nozzle) Weld Component Identification:
Listed in Table 1 Material:
SA533, GR B carbon steel
- 2. Applicable Code Addition and Addenda ASME Section XI, 2004 Edition, No addenda
3. Applicable Code Requirement
ASME Section XI, 2004 Edition, Category C-B requires volumetric examination of 100 percent (%) of the weld volume as defined in Table IWC-2500-1 and shown in Figure IWC 2500-4. The alternative requirements of ASME Section XI, Code Case N-460, approved for use in Regulatory Guide 1.147, Revision 18, allows credit for essentially 100% coverage of the welds provided greater than 90% of the required volume has been examined.
4. Impracticality of Compliance
Pursuant to 10 CFR 50.55a(g)(5)(iii), relief is requested from the 100% volumetric examination coverage requirement of the subject welds due to the geometric configuration and permanent obstructions which limit the volumetric coverage that can be obtained.
The subject steam generator nozzle welds were examined with a manual ultrasonic technique using equipment and procedures written in accordance with ASME Section XI, Appendix 1 and Section V, Article 4 to achieve the maximum examination coverage practical.
Limitations imposed by the nozzle configuration preclude obtaining 100% coverage.
This configuration with the nozzle outside
Serial No.19-386 Docket No. 50-336, Page 2 of 8 radius within close proximity of the weld prevents complete scanning in these areas due to lift-off of the search unit that occurs causing a loss of contact between the search unit and the component. An additional limitation was encountered with the examination of the main steam nozzle to head weld (SG-2-MS-1) due to six permanently welded insulation retaining lugs that are located within close proximity of the weld that restricts the scanning in these areas on the head side of the weld.
The required examination volume of these welds was interrogated ultrasonically to the maximum extent possible. No alternative techniques or advanced technologies were considered capable of obtaining complete coverage of the examination volume.
Weld isometric drawing, coverage calculations and limitation sketches are provided in this attachment.
SG-1-FW-1 (2.21 SG-2-MS-1 (2.21 TABLE 1-Examination Category C-B Welds with Limited Volumetric Coverage Feed Water Steam Generator No. 1 Feed Water Nozzle to Shell Weld Main Steam Main Steam Nozzle to Head Weld oo 45° 60° Long. Wave Shear Wave Shear Wave 0° Long. Wave 45° Shear Wave 60° Shear Wave Scan Limitations due to the configuration of the nozzle restricting the scans from the nozzle side of the weld.
No recordable indications were detected.
Scan Limitations due to the configuration of the nozzle restricting the scans from the nozzle side of the weld.
Additional limitation from the head side of the weld due to six permanently welded insulation retaining lugs located within close proximity of the weld.
No recordable indications were detected.
88.8%
73.6%
Serial No.19-386 Docket No. 50-336, Page 3 of 8 Magnetic particle examination performed obtaining 100% coverage. No recordable indications detected.
Magnetic particle examination performed obtaining 100% coverage. No recordable indications detected.
5. Burden Caused by Compliance
Serial No.19-386 Docket No. 50-336, Page 4 of 8 To increase examination coverage on the subject welds would require a significant design modification or replacement of components with a different design to eliminate the noted obstructions. This is considered impractical due to cost, increased radiation exposure, and impact to plant equipment.
6. Proposed Alternative and Basis for Use
The subject welds received a volumetric examination to the maximum extent practical. Additionally, these components are monitored for through-wall leakage as part of the ASME Section XI System Pressure Test Program and receive a visual (VT-2) examination at the end of each inspection period during the system leakage tests required by Section XI, Table IWC-2500-1, Category C-H for class 2 components.
Based upon the examination volumes that were obtained with acceptable results along with the visual (VT-2) examination performed each inspection period, it is reasonable to conclude that service-induced degradation would be detected.
Therefore, these proposed alternatives will provide an acceptable level of quality and safety by providing reasonable assurance of structural integrity of the subject welds.
7. Duration of Proposed Alternative
The relief is requested for the fourth ten-year inspection interval for Millstone Power Station Unit 2, which began on April 1, 2010 and will end March 31, 2020.
- 8. Precedent A similar relief request was approved for use at MPS2 during the third 10-year ISi interval (i.e., Relief Request RR-89-73 (ADAMS Accession No. ML120541062)).
TOP LOWER PORilOO 0"**N*L G<Nmw* *
- I **
RffiACE"6NT GEOl91<<-ro* 19'><
NOZZLE (1)
G'-ea/4'.' (APRO)Ll MAIN STEAM NOZZLE (I) 1B
---I-+--------; -f----
l,...s
!rA SUPPORT-:\\1>2 ELEVATION SUPPORT l4 180
° SECTION A*A UIN'.Cllt.
nm.CK.
antUC.CK.
tllCM. CK.
CONC. CK, trtuaL tit.
UIIV.ar.*
a,mCIL ST11UC.CK.
MICM.CX.
COffC.at.
H'flliln..CIC.
oo 1B0° SECTION B*B tutY.Clf.
ntc.CIC.
l'nlVC,Clt.
MICH. ar.
C0NC. CL 0 CK.
TBFISC*2A SECONDARY.
MANWAYS R£\\!IS!ONS DURING CONSTRUCTION I P.A. NO.
I
Ol 0
- r 3
CD = (/)
- i o CD
>A°::!
.
-Uzz Ol O 0 (Cl CD CJ1 _._
o,oco I
I OWW
-woo
- 0) 0) 0)
/
STEAM NOZZLE (I)
Sif-2-THS-2 SUPPORT f4 opIJ!i.1.. G,9JJreA1" q
REPLACEMEt-11" eaie:t-.lERA,ce TQP I
LoWe, --=*
l"l"IZ.
18 SECONDARY MANWAY (2)
SUPPORr-l'f1 SUPPORT""3
'7-s
'7-A SUPPORT!;l-2 ao 1ao0 SECTION A-A
@_'* 83/4." (APPROX.
ELEVATION o*
SUPPORT¥\\
1so0 SECTION B-B
-.... =- *, :::
IUIY.CK..
nte.CIL IUCH.Clt.
COlfC.Clt..........
llfCH,CK. =-.........
SECONDARY MANWAYS
\\
REVISIONS DURING CONSTRUCTION I P.A. NO.
.. :. ZONE. 2.- 2-A
Dl
()
- J" 3
CD (/)
()
N;,;- __
- m.
-Ozz Dl O 0 co.
CD 01...,,_
moco I
I 0 WW
-wco comm
~
.1"*100%
60° OS (US skip) we1r7710° us Weld l.1"*1003/4
?
.1"*100%
G:;::.l:;;:;:::r:;;t;:;;;/;;:;:!::0;;;:::::,::;:!12:$
V/1 Total Code Exam Volume
[LLJ 3.l" 0 exam area 0.0"=0%
Weld ID: SG-1-FW-1 4.915 4.910 45° Coverage Total:
0°=0%
45 us = 100%
45 OS = 100%
45CW = 100%
45CCW= 100%
60US= 100%
60DS= 100%
60CW = 100%
60CCW= 100%
Total: 800 / 9 = 88.8%
Scale 1:3 60° Vessel Ol
(")
- J" 3
Cl) 2? (/)
(")
Cl)
$E.
7Jz z Ol O 0 c.o.
Cl) u, _,.
--.J O CD oww
....., (.,.) co COO)O)
Weld ID: SG-2-MS-1 (tfl 45 4.86" Total examination volume= 96.75" (Weld Length) x 3.44square inches (Weld volume)= 332.82 cubic inches Examined 100% orrcquired volume with 0 planar, 45 CW&CCW, 60 CW&CCW Coverage Total 0 Planar 45 Upstream 45 Downstream 45 Clockwise 45 Counterclockwise 60 Upstream 60 Downstream 60 Clockwise 60 Countcrclockwiúc 100.0%
81.4%
0.0%
100.0%
100.0%
Xl.4%
0.0%
100.0%
100.0%
Total: 662.8%/9= 73.6%
Ins. Lug_
L Total examination volume= 96.75" (Weld Length) x 3.44square inches (\\.Veld volume)= 332.82.cubic inches
I
-h.1s Nozzle No axial examinations 45 and 60 for IS inches of weld length clue to insulation lugs located 2.75" from weld centerline. equally spaced at 6 locations around the weld circumference. 45 and 60 do not impinge on the examination volume at these locations.
332.82 cubic inches - ( 18" x 3.44 squaure inches)= 270.9 cubic inches examined 270.9/332.83= 81.4% examined
OJ(")
<D O (/)
g <D Nûü-
,-+ -
-Uzz OJ O 0 co.
<D (J1 --"-
00 0 (0 Q(,.)(,.)
--+, <,.) 00 000)0)
ATTACHMENT 3 RELIEF REQUEST RR-04-30 EXAMINATION CATEGORY R-A RISK INFORMED PIPING EXAMINATIONS DOMINION ENERGY NUCLEAR CONNECTICUT, INC.
MILLSTONE POWER STATION UNIT 2 Serial No.19-386 Docket No. 50-336
Serial No.19-386 Docket No. 50-336, Page 1 of 13 1 0 CFR 50.55a Request Number: RR-04-30 Relief Requested In Accordance with 10 CFR 50.55a(g)(5)(iii)
In-service Inspection Impracticality
- 1. ASME Code Components Affected:
ASME Code Class:
Code Class 1 and 2 Examination Category:
R-A, Risk-Informed Piping Examinations Item Numbers:
R 1.11, Elements Subject to Thermal Fatigue R1.20, Elements not Subject to a Degradation Mechanism R1.16, Elements Subject to lntergranular or Transgranular Stress Corrosion Cracking (IGSCC or TGSCC)
Component Identification:
Listed in Table 1 Material:
Type 316 Austenitic Stainless Steel or SA 106 GR B Carbon Steel (as shown in Table 1) with Stainless Steel or Carbon Steel type weld filler metal. The subject welds contain no Alloy 600/82/182 material.
- 2. Applicable Code Addition and Addenda ASME Section XI, 2004 Edition, No Addenda
3. Applicable Code Requirement
The examination requirements for Class 1 and Class 2 piping welds are governed by the risk-informed In-Service Inspection program that was approved by the NRC in a letter dated March 27, 2012 (ADAMS Accession Number ML120800433). The program was developed in accordance with ASME Code Case N-716, "Alternative Piping Classification and Examination Requirements."
Code Case N-716, Table 1, Examination Category R-A, requires that essentially 100 percent (%) of the weld volume be examined. The alternative requirements of ASME Code Case N-460, approved for use in Regulatory Guide 1.147, Revision 18, allows credit for essentially 100% coverage provided greater than 90% of the required volume has been examined.
Serial No.19-386 Docket No. 50-336, Page 2 of 13 10 CFR 50.55a(b)(2)(xv)(A), requires the following examination coverage criteria when applying Supplement 2 (Qualification Requirements for Wrought Austenitic Piping Welds) to Section XI Mandatory Appendix VIII (Performance Demonstration for Ultrasonic Examination Systems):
(1)
Piping must be examined in two axial directions and when examination in the circumferential direction is required, the circumferential examination must be performed in two directions, provided access is available.
(2)
Where examination from both sides is not possible, full coverage credit may be claimed from a single side for ferritic welds. Where examination from both sides is not possible on austenitic welds, full coverage credit from a single side may be claimed only after completing a successful single sided Appendix VIII demonstration using flaws on the opposite side of the weld.
10 CFR 50.55a(b)(2)(xvi)(B), requires that examinations performed from one side of a ferritic or stainless steel pipe weld must be conducted with equipment, procedures, and personnel that have demonstrated proficiency with single side examinations.
To demonstrate equivalency to two-sided examinations, the demonstration must be performed to the requirements of Appendix VIII, as modified by this paragraph and 10 CFR 50.55a(b)(2)(xv)(A).
4. Impracticality of Compliance
Pursuant to 10 CFR 50.55a(g)(5)(iii), relief is requested from the 100%
volumetric examination coverage requirement for the subject austenitic welds due to the geometric configuration which limits the volumetric coverage that can be obtained.
The subject welds were examined with a manual ultrasonic technique utilizing personnel, equipment and procedures qualified in accordance with ASME Section XI, Appendix VIII as implemented by the Performance Demonstration Initiative (POI).
There are currently no POI qualified single side examination procedures that demonstrate equivalency to two-sided examination procedures on austenitic piping welds. Current technology is not capable of reliably detecting or sizing flaws on the far side of an austenitic weld for configurations common to domestic nuclear applications.
POI Performance Demonstration Qualification Summary (PDQS) certificates for austenitic piping list the limitation that single side examination is performed on a
- best effort basis. The best effort qualification is provided in place of a complete single side qualification to demonstrate that the examiners qualification and the subsequent weld examination is based on application of the best available technology.
Serial No.19-386 Docket No. 50-336, Page 3 of 13 When the examination area is limited to one side of an austenitic weld, examination coverage does not comply with 10 CFR 50.55a(b)(2)(xv)(A) and proficiency demonstrations do not comply with 10 CFR 50.55a(b)(2)(xvi)(B) and full coverage credit may not be claimed.
The ASME code required volume of these welds was interrogated ultrasonically to the maximum extent possible.
No alternative methods or advanced technologies, including the use of phased array, were considered capable of obtaining complete coverage of the examination volume.
The subject welds consist of a pipe-to-valve or pipe-to-tee configuration in which the tapered surface of the valve or the branch of the tee is within close proximity of the weld and limit the ability to scan from that side of the weld.
There are no welds in this request that are within the scope of the Electric Power Research Institute (EPRI) document MRP-146 (Management of Thermal Fatigue in Normally Stagnant Non-lsolable Reactor Coolant System Branch Lines) requirements.
Based on the configuration limited to single sided access, relief is requested from complying with the 100% required examination coverage for the piping welds listed in Table 1. Note that examination coverage listed in Table 1 is that which was obtained during examination with no credit taken for the far side of each weld.
Supplemental scanning was performed to provide additional best effort (non code) coverage as documented on the enclosed coverage calculation for each weld.
Coverage calculations are provided in this attachment.
Weld Identification BCH-C-1007 A BSI-C-3010-A Serial No.19-386 Docket No. 50-336, Page 4 of 13 Table 1-Examination Category R-A Welds with Limited Volumetric Coverage Code I System / Code Class I Examination Angle and Configuration Item#
Materi.al Wave Mode Rl.11 I Charging/ Class 1 45° Shear Wave 45° Shear Wave 2" Pipe-to-Tee 60° Shear Wave Type 316 Stainless Steel, I 70° Shear Wave Rl.16 Schedule 160 Safety Injection/ Class 1 12" Pipe-to-Valve Type 316 Stainless Steel, Schedule 140 45° 60° 60° Shear Wave Shear Wave Long Wave Limitations and Results Examination is limited on the upstream side due to Tee configuration. The branch of the Tee is within close proximity of the weld. There is not sufficient distance from the weld to the Tee to perform any scanning on the Tee side of the weld No recordable indications were detected.
This was a pre-service examination associated with a new weld. Examination is limited to the pipe side only due to the taper of the valve being within close proximity of the weld.
There is not sufficient distance from the weld to the valve to perform any scanning on the valve side of the weld.
No recordable indications were detected.
Exami.nation Coverage(%)
82.5%
50%
Weld Identification BSI-C-3012-A BPV-C-5104A FWB-C-G-17-A Code I. Item#
Rl.16 Rl.20 Rl.20 System I Code Clc1ss Configuration Material Examination Angle and Wave Mode Safety Injection/ Class 1 I 45° 60° Shear Wave Long Wave 12" Pipe-to-Valve Type 316 Stainless Steel, Schedule 140 Reactor Coolant/ Class 1 I 45° Shear Wave 4" Pipe-to-Tee Type 316 Stainless Steel, Schedule 120 Main Feedwater / Class 2 6" Pipe-to-Valve SA106 GR B Carbon Steel, Schedule 40 70° Shear Wave 45° 60° 70° Shear Wave Shear Wave Shear Wave Serial No.19-386 Docket No. 50-336, Page 5 of 13 Limitati.ons and Results This was a pre-service examination associated with a new weld. Examination is limited to the pipe side only due to the taper of the valve being within close proximity of the weld.
There is not sufficient distance from the weld to the valve to perform any scanning on the valve side of the weld.
No recordable indications were detected.
Examination is limited due to Tee configuration. The branch of the Tee is within close proximity of the weld. There is not sufficient distance from the weld to the Tee to perform any scanning on the Tee side of the weld.
No recordable indications were detected.
This was a pre-service examination associated with a new weld. Examination is limited to the pipe side only due to the taper of the valve being within close proximity of the weld.
There is not sufficient distance from the weld to the valve to perform any scanning on the valve side of the weld. One recordable indication evaluated geometry.
was detected which as acceptable weld was root Examiha{ion Coverage (%)
50%
89.5%
81.2%
Weld Identification SI-CF-O-035 Code Item#
Rl.20 System I Code Class Configuration Material El3ri1in§tion Angle and WaveMode High Pressure Safety 145° Shear Wave Injection/ Class 1 70° Shear Wave 3" Pipe-to-Valve Type 316 Stainless Steel, Schedule 160 Serial No.19-386 Docket No. 50-336, Page 6 of 13 Limitations and Results This was a pre-service examination associated with a new weld. Examination is limited to the pipe side only due to the taper of the valve being within close proximity of the weld.
There is not sufficient distance from the weld to the valve to perform any scanning on the valve side of the weld.
One recordable indication was detected which was evaluated as acceptable weld root geometry.
Examination Coverage(%)
50%
5. Burden Caused by Compliance
Serial No.19-386 Docket No. 50-336, Page 7 of 13 Compliance with the Code requirements would require extensive modification or replacement of components with a design that would allow full examination from both sides of the weld. This is considered impractical based on cost, increased radiation exposure, and impact to plant equipment.
6. Proposed Alternative and Basis for Use
The subject welds received a volumetric examination to the maximum extent practical utilizing the best available techniques, as qualified through the POI for Supplement 2, with demonstrated best effort for single sided examination from the accessible side of the weld.
Also, these components are monitored for through-wall leakage as part of the ASME Section XI System Pressure Test Program and receive a visual (VT-2) examination at the end of each refueling outage during the system leakage tests as required by Section XI, Table IWB-2500-1, Category B-P for Class 1 components and Table IWC-2500-1, Category C-H for Class 2 components.
Based on the volumetric coverage that was obtained with acceptable results and the visual (VT-2) examination performed each refueling outage, it is reasonable to conclude that service-induced degradation would be detected.
Therefore, these proposed alternatives will provide an acceptable level of quality and safety by providing reasonable assurance of structural integrity of the subject welds.
7. Duration of Proposed Alternative
Relief is requested for the fourth ten-year inspection interval for Millstone Power Station Unit 2, which began on April 1, 2010 and ends March 31, 2020.
- 8. Precedent A similar relief request was approved for use at MPS2 during the first period of the fourth 10-year ISi interval (i.e., Relief Request RR-04-19 (ADAMS Accession No. ML16172A135)).
Serial No.19-386 Docket No. 50-336, Page 8 of 13 Coverage Summary-Weld# BCH-C-1007A R eport No:
I Summary:
I Page:
I By:
I MT-2-UT-15-008 I M2.R11.0055 I 5 of6 I D.R. Cordes/ LIii I Examination Volume Dimensions: Length 4.7" x Width 1.50" K Height Weld Thickness= 0.36" Weld Length=
4.7" Weld Width= 0.5"
,/Flow 45°/70° (max W2 position) 45 ° 70°
. -----1---
Pipe
'( ;?s;i?
Tee Body
'\\{A2 Area 3 Required Examination Volume- 0.18 Sq" (1.50" x 0.12" = 0.18 Sq" or 0.09 Sq" per side)
Area oflimitation (tee config) - 0.062 Sq" (0.09 - 0.62) I 0.9 = 31. l %
Supp 70° - (Up scan for Dn scan credit - best effort)
Obtained additional 0.014 sq in on tee side 0.014/0.09= 15.5%
Area I L:::::::::... Area 3 Date:
10/10/15
.12" Required Scans-each has a weighing factor of 100% for complete coverage Angle Upstream-Axial Upstream-Circ.
Downstream Axial Downstream Circ.
45°/70° 31%
100%
100%
100%
70° -Best Effort 15.5%
N/A N/A N/A 31+1oo+100+100=331/4=82.50%
Code Coverage Total 82.5%
34.9+1oo+1oo+100=83.3%
Best Effort Coverage (Max 25%) Total 3.9% (Tee Side)
Notes:
- 1. Code Coverage refers to the maximum percentage of the required examination volume that is effectively examined with the qualified examination procedure
- 2. Best Effort Coverage refers to the required examination volume past the centerline that is examined in the axial beam direction with an Appendix VIII demonstrated procedure for single sided coverage (Area dimensions determined with Turbocad)
Valve FLOW
1.242" 1.275" 60° RL L__
Serial No.19-386 Docket No. 50-336, Page 9 of 13 Pipe 1.200" 1.200" 60° 45° Required Examination Volume:
0.9184 Sq. Inches Far Side Examination Volume:
0.4458 Sq. Inches Best Effort Examination Volume:
0.4187 Sq. Inches Far side examination volume limited due to single sided access.
Limited area scanned with 2.0 MHZ 60 degree for best effort coverage.
(Area dimensions determined with Turbo CAD 18)
Examination Volume Dimensions: Length 40.75" x Width 2.1" X
Height 0.414" Weld Thickness= 1.24" Weld Length=
40.75" Weld Width= 1.1" Coverage Summary-Weld# BSI-C-3010-A Required Scans-each has a weighing factor of 100% for complete coverage Angle Upstream-Axial Upstream-Circ.
Downstream Axial Downstream Circ.
45/60° 100%
100%
0%
0%
60°RL 93.9% (BEST EFFORT)
Code Coverage Total 50%
(100+100+0+0)/4=50%
Best Effort Coverage (Max 25%) Total 23.4%
Notes:
- 1. Code Coverage refers to the maximum percentage of the required examination volume that is effectively examined with the qualified examination procedure 2.
Best Effort Coverage refers to the required examination volume past the centerline that is examined in the axial beam direction with an Appendix VIII demonstrated procedure for single sided coverage
Serial No.19-386 Docket No. 50-336, Page 10 of 13 45° Required Exam Volume -.7478 Sq. in (1.90*.39=.741 Sq. in)
Flow 1.13 1.15 1.14 1.17 1.19 NR Far Side Required Exam Volume -.3702 Sq. In H
(.95*.39 =.3705 Sq. in)
I Volume Examined on Far Side -.3702 Sq. in (100%) '
(Best Effort)
Valve (Area dimensions determined with TurboCAD 19)
Examination Volume Dimensions: Length 40.25" x Width 1.90" x Height Weld Thickness= 1.17" Weld Length=
40.25" Weld Width=.90" Coverage Summary-Weld # BSI-C-3012-A
.39" Required Scans-each has a weighing factor of 100% for complete coverage Angle Upstream-Axial Upstream-Clrc.
Downstream Axial Downstream Circ.
45 100%
100%
0%
0%
60 100%(Best Effort)
Code Coverage Total 50%
100+100+100+0=300/4=75%
Best Effort Coverage (Max 25%) Total 25%
Notes:
- 1. Code Coverage refers to the maximum percentage of the required examination volume that Is effectively examined with the qualified examination procedure
- 2. Best Effort Coverage refers to the required examination volume past the centerline that is examined in the axial beam direction with an Appendix VIII demonstrated procedure for single sided coverage
Serial No.19-386 Docket No. 50-336, Page 11 of 13 Coverage Summary - Weld # BPV-C-5104A Report No:
I Summary:
I Page:
I By:
I Date:
M2-UT-15-00S I M2.R1.20.0024 I 3 of 4 I D.R. Cordes / LIii I 10/13/15 Examination Volume Length 14.2" X Width 1.80" Height 0.15" Dimensions:
X Thickness=
0.44" Weld Length=
14.2" Weld Width= 0.8" Limited Ax Dn scan of 6" (3" on each side of tee "radius" area) 0.6" Tee (Flush) 0.53" 0.53" 0.44" Flow 0.44" (T&C from 2006 Data)
Required Examination Volume- 0.354 Sq. In."
Irregular. Determined by CAD 0.354 sq in in. 0.138(pipe)/0.216(tee) 0.354 sq in x 14.2 = 5.03 Total Vol 0.138 x 14.2 = 1.96 Vol Pipe side 0.216 x 14.2 = 3.07 Vol Tee side 0.216x 14.2x0.9=2.76 Supp 70° - (Up scan for Dn scan credit - best effort)
Irregular - determined by CAD (tee limitation) 0.216" I 3.07 = 7%
0.216 X 6 X 0.9 = 1.17 1.17 / 2.76 = 42%
[
Pipe Required Scans-each has a weighing factor of 100% for complete coverage Angle Upstream-Axial Upstream-Circ.
Downstream Axial Downstream Circ.
45° 100%
100%
58%
100%
70° -Best Effort N/A N/A 42% (from Pipe)
N/A 100+10o+58+100=358.6/4=89.5%
Code Coverage Total 89.5%
100+ 100+ 100+100=400/ 4=100%
Best Effort Coverage {Max 25%) Total 10%
Notes:
- 1. Code Coverage refers to the maximum percentage of the required examination volume that is effectively examined with the qualified examination procedure
- 2. Best Effort Coverage refers to the required examination volume past the centerline that is examined in the axial beam direction with an Appendix VIII demonstrated procedure for single sided coverage (Area dimensions determined with Turbocad)
NR Valve Serial No.19-386 Docket No. 50-336, Page 12 of 13
/ Flow NR
.324" 01111111110
.290"
.281" Pipe Required Examination Volume =.17 Sq. in
(.10*1.50 =.15 Sq. in Far Side Required Exam Volume -.08 Sq. in
(.75"*.10 =.08 Sq. in)
No Coverage _____-,,
IU Volume Examined on Far Side -.02 Sq. in (25%)
(Area dimensions determined with TurboCAD 19)
Examination Volume Dimensions: Length 21.0" Weld Thickness=
.324" Weld Length=
21.0" x Width 1.50" Weld Width=
.SO" X
Height Coverage Summary-Weld# FWB-C-G-17-A
.10" Required Scans-each has a weighing factor of 100% for complete coverage Angle Upstream-Axial I
Upstream-Clrc.
I Downstream Axial I Downstream Circ.
45°/60°/70° 100%
I 25%
I 100%
I 100%
Code Coverage Total I 81.2%
(100+2s%+100+100)14= I Best Effort Coverage (Max 25%) Total I N/A Notes:
1.
Code Coverage refers to the maximum percentage of the required examination volume that is effectively examined with the qualified examination procedure
Serial No.19-386 Docket No. 50-336, Page 13 of 13 Flow Valve
.50.47.46.45.45 Required Exam Volume -.2717 Sq. in txX><XXXXXXXX>© (1.60*.16 =.256 Sq. in)
Far Side Required Exam Volume-.1471 Sq. In fn1//Zl
(.80*.16=.128 Sq. in)
Volume Examined on Far Side -.1256 Sq. in (85%) ir::?Z,1//21 (Best Effort) 45° Pipe (Area dimensions determined with TurboCAD 19)
Examination Volume Dimensions: Length 11.4" x Width 1.60" X Height Weld Thickness=
11.4" Weld Width=
.60" Coverage Summary-Weld# SI-CF-D-03S(W26)
.16" Required Scans-each has a weighing factor of 100% for complete coverage Angle Upstream-Axial Upstream-Circ, Downstream Axial Downstream Circ.
45 0%
0%
100%
100%
70 85%(Best Effort)
Code Coverage Total 50%
0+85+100+100=285/4=71%
Best Effort Coverage (Max 25%) Total 21%
Notes:
- l. Code Coverage refers to the maximum percentage of the required examination volume that is effectively examined with the qualified examination procedure 2.
Best Effort Coverage refers to the required examination volume past the centerline that is examined In the axial beam direction with an Appendix VIII demonstrated procedure for single sided coverage