ML18086A029
| ML18086A029 | |
| Person / Time | |
|---|---|
| Site: | Surry |
| Issue date: | 03/21/2018 |
| From: | Mark D. Sartain Virginia Electric & Power Co (VEPCO) |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| Download: ML18086A029 (18) | |
Text
- J.
VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 March 21, 2018 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 VIRGINIA ELECTRIC AND POWER COMPANY SURRY POWER STATION UNIT 1 ASME SECTION XI INSERVICE INSPECTION PROGRAM 10 CFR 50.55a Serial No.18-042 SPS-LIC/CGL R2 Docket No.
50-280 License No.
DPR-32 RELIEF REQUESTS FOR LIMITED COVERAGE EXAMINATIONS PERFORMED IN THE FIRST PERIOD OF THE FIFTH 10-YEAR INSERVICE INSPECTION INTERVAL Virginia Electric and Power Company (Dominion Energy Virginia) performed inservice inspection (ISi) examinations at Surry Power Station Unit 1 for the first period of the fifth 10-year ISi interval, which began on December 14, 2013 and will end on October 13, 2023. Examinations of certain components conducted during the first period of the fifth interval received less than the required examination coverage.
Pursuant to 10 CFR 50.55a(g)(5)(iii), Dominion Energy Virginia requests relief for the limited examinations on the basis that the required examination coverage was impractical due to physical obstructions and limitations imposed by the design and geometry of the subject components. Attachments 1 and 2 contain the specific relief requests and the 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 Mr. Gary D. Miller at (804) 273-2771.
Sincerely,*
Mark D. Sartain Vice President - Nuclear Engineering and Fleet Support Commitments made in this letter: None Attachments:
- 1. Relief Request S1-15-LMT-C01, Examination Category 8-D, Pressurizer Nozzle Inner Radius Section
- 2. Relief Request S1-15-LMT-P01, Examination Category R-A, Preservice Weld Examinations
Serial No.18-042 Docket No. 50-280 Relief Requests for 1st Period of 5th Interval Limitec:I Coverage Examinations Page 2 of 2 cc:
U.S. Nuclear Regulatory Commission, Region II Marquis One Tower 245 Peachtree Center Avenue NE, Suite 1200 Atlanta, Georgia 30303-1257 NRC Senior Resident Inspector Surry Power Station Ms. K. R. Cotton-Gross NRC Project Manager - Surry U. S. Nuclear Regulatory Commission One White Flint North Mail Stop 08 G-9A 11555 Rockville Pike Rockville, Maryland 20852 Mr. J. R. Hall NRC Senior Project Manager - North Anna U.S. Nuclear Regulatory Commission One White Flint North Mail Stop 08 B-1 A 11555 Rockville Pike Rockville, Maryland 20852 Mr. R. A. Smith Authorized Nuclear Inspector Surry Power Station Serial No.18-042 Docket No. 50-280 Relief Request S1-15-LMT-C01, Examination Category B-D, Pressurizer Nozzle Inner Radius Section Virginia Electric and Power Company (Dominion Energy Virginia)
Surry Power Station Unit 1
Dominion Energy Virginia Surry Power Station Unit 1 5th 10-Year Interval December 14, 2013 - October 13, 2023 Pressurizer Nozzle Inner Radius Section Relief Request S1-15-LMT-C01 In Accordance with 10 CFR 50.55a(g)(5)(iii)
18NIR Drawing:
11448-WMKS-RC-E-2 ASME Class:
1 ASME Category:
8-D ASME Item:
83.120 Serial No.18-042 Docket No. 50-280 Page 1 of 5
==
Description:==
Pressurizer Nozzle Inner Radius Section Material: SA-216 Grade wee cast carbon steel Operating Pressure: 2235 psig Operating Temperature: 650 °F
2. Applicable Code Edition and Addenda
2004 Edition of ASME Section XI
3. Applicable Code Requirement
The 2004 Edition of ASME Section XI does not require examination of Class 1 Nozzle Inner Radius (NIR) Sections.
However, the Code of Federal Regulations, Part 50.55a(2)(xxi), conditions the requirements of ASME Section XI, Table IW8-2500-1, Examination Category 8-D.
The condition mandates that the 1998 Edition of Section XI be used which requires examination of the Class 1 NIRs by items 83.120 and 83.140. Either an ultrasonic or enhanced visual examination from the inner diameter (ID) shall be performed.
4. Impracticality of Compliance
Serial No.18-042 Docket No. 50-280 Page 2 of 5 The pressurizer is covered with an insulation support structure (Figure 1 ). As can be seen in the figure, the support structure interferes with completion of a full volumetric examination around the circumference of the 18NIR nozzle to pressurizer safety valve. The examination was further limited by the rough exterior surface on the pressurizer vessel head which restricted adequate UT probe contact in several areas. Figure 2 illustrates the areas of limitation.
5. Burden Caused by Compliance
Total removal of the support structure at the mechanical connections is considered impractical due to the extreme high dose rates in the pressurizer area. Furthermore, this is not a viable effort when considering consequential disturbance of interconnected cross supports and the welded connections to safety and power operated relief valve supports. Removal of the mechanical connections or forced spreading apart of components would create a risk of misalignment and possibly warp the structure.
Civil engineering proposed that cutting the support could be necessary for removal; thus, destroying the support structure.
6. Proposed Alternative and Basis for Use
Component 18NIR was ultrasonically examined using an NOE procedure that incorporates EPRI modeling report IR-2012-485 specific to the Surry Unit 1 pressurizer safety/relief nozzles. This modeling report details the required ultrasonic scan parameters which should be applied to achieve full coverage of the examination volume.
Modeling report IR-2012-485 requires a combination of ultrasonic scanning both from the nozzle blend region and the pressurizer vessel head. Different transducer angles, skews and wedge contours were used for the required scans. The prior ultrasonic examination performed during the fourth ISi interval consisted of only scanning from the nozzle blend region; scanning was not required from the vessel head. The majority of the documented limitations (98.0%)
occurred in the region on the vessel head that was not previously scanned.
No additional ultrasonic examination techniques would provide meaningful additional data on this cladded material for the examination volume not attained.
The pressurizer receives a visual (VT-2) examination every refueling outage as required by Section XI, Table IWB-2500-1, Category B-P for Class 1 components performed at normal operating pressure and temperature.
Any effort to achieve greater coverage would be impractical due to creating risk of component damage or destruction and excessive personnel dose exposure.
Serial No.18-042 Docket No. 50-280 Page 3 of 5 The nozzle inner radius sections are not welds but actually cast material components. There have been no known through wall flaws in Class 1 nozzle inner radius section components. Similar pressurizer nozzle inner radius section 19NIR was examined on Unit 1 during the fifth interval October 26, 2016, and greater than 90% coverage was obtained with no indications.
It is proposed that the scanning percentage coverage obtained (81.67%) with no recordable indications be considered as meeting the Code requirements.
7. Duration of Proposed Alternative
This proposed alternative is requested to meet requirements for the fifth ten-year ISi interval for Surry Power Station Unit 1, which began December 14, 2013 and will end October 13, 2023.
Pressurizer Nozzle to Pipe Safety/Relief Valve Support Serial No.18-042 Docket No. 50-280 Page 4 of 5 Insulation Support Frame
~
Pressurizer Insulation Support Rings Figure 1 Pressurizer Insulation Support Structure
1-RC-18NIR Serial No.18-042 Docket No. 50-280 Page 5 of 5 Report No: UT-16-050 Summary No: Sl.63.120.001 Pg. 2 of2 Date: 10/26/2016 Limitation Sketch and Coverage of Scan Surface 1'1 Surface lndentallon Nea
- 1.73 In'
- l S..-luc JodrnloUOtl Aroa* 1.161n'
- l Sw6.ce lnde:n&alion A... -o.n1n1 90° 180*
-270°
~ 1n,1.11aaon Sl!J>Potl Ring Area
- 34.82 In'
- IS Sl."1ace lndentalion Area* 12.31 In'
- S 8urface lndenta11on Ne.a
- 6.3l ln7 The scan surfaces (blend and vessel) for "I-RC-18NIR were obstructed by the PZR Insulation Support Ring and also limited by surface Indentations which did not allow for adequate probe contact.
The total area of scanning surface Is 580.32 In.'*
The total area ofHmited scanning Is 106.38 in.'.
Total percentage limited= (106.38/580.32) x 100 = 18.33%
Percentage of scan area scanned = 100% - 18.33% = 81.67%
Figure 2 Limitations Sketch for 18NIR Serial No.18-042 Docket No. 50-280 Relief Request S1-15-LMT-P01, Examination Category R-A.
Preservice Weld Examinations Virginia Electric and Power Company (Dominion Energy Virginia)
Surry Power Station Unit 1
Dominion Energy Virginia Surry Power Station Unit 1 5th 10-Year Interval December 14, 2013 - October 13, 2023 ASME XI Preservice Pipe Welds Relief Request# S1-15-LMT-P01 Repetitive/Duplicate Relief Requests In Accordance with 10 CFR 50.55a(g)(5)(iii)
Code Class 1 Serial No.18-042 Docket No. 50-280 Page 1 of 9 Examination Category:
R-A, Risk Informed Piping Examinations Stainless Steel Piping Item Numbers:
Component Identification:
Material:
R1.20, High Safety Significant not Subject to a Degradation Mechanism Refer to Specific Table Refer to Specific Table
2. Applicable Code Edition and Addenda
2004 Edition of ASME Section XI
3. Applicable Code Requirement
Required Method: Surface and Volumetric for preservice requirements The alternative requirements of ASME Section XI, Code Case N-460, approved for use in Regulatory Guide 1.147, Rev.17, allows credit for essentially 100% coverage of the weld provided greater than 90% of the required volume has been examined.
10 CFR 50.55a(b)(2)(xv)(A), requires the following examination coverage criteria when applying Supplement 2 to Appendix VIII :
Serial No.18-042 Docket No. 50-280 Page 2 of 9 (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 on austenitic welds or dissimilar metal 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 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 in accordance with the requirements of Appendix VIII as conditioned by 10 CFR 50.55a(b)(2)(xvi)(B) and §50.55a(b)(2)(xv)(A).
4. Impracticality of Compliance
Pursuant to 10 CFR 50.55a(g)(5)(iii), relief is requested from the volumetric examination coverage requirements for the subject welds due to the geometric configuration that limits the volumetric coverage that can be obtained.
For the austenitic weld, 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.
There are currently no Performance Demonstration Initiative (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 U.S. nuclear applications. However, 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 examiner's qualification and the subsequent weld examination is based on application of the best available technology.
The subject welds were examined with a manual ultrasonic technique (UT) using pulse echo UT instruments and search units to achieve the maximum examination coverage practical. Examinations were performed using personnel, equipment and procedures qualified in accordance with ASME Section XI, Appendix VIII as
Serial No.18-042 Docket No. 50-280 Page 3 of 9 implemented by the POI. No alternative welds were considered since these are preservice examinations for each specific weld that was reconstructed.
Specific examination coverage and component details are provided in Table P01.
Weld 2-178 Summary# S1.R1.20.091 This is a stainless steel ASME XI, Category R-A weld, Item R1.20, High Safety Significant not subject to a degradation mechanism.
The weld configuration is stainless steel (ASTM 376, Type 316) pipe to a stainless steel valve (ASTM 351).
This new weld also received volumetric examination by radiography and a liquid penetrant surface examination for preservice with no unacceptable flaws or indications detected.
When the system reached operating pressure and temperature, the weld was further inspected visually (VT-2) for through-wall leaks with none detected.
Weld 2-188 Summary# S1.R1.20.092 This is a stainless steel ASME XI, Category R-A weld, Item R1.20, High Safety Significant not subject to a degradation mechanism. The weld configuration is a stainless steel valve (ASTM 351) to stainless steel pipe (ASTM 376, Type 316). This new weld also received volumetric examination by radiography and a liquid penetrant surface examination for preservice with no unacceptable flaws or indications detected.
When the system reached operating pressure and temperature, the weld was further inspected visually (VT-2) for through-wall leaks with none detected.
Weld 1-18A Summary# S1.R1.20.095 This is a stainless steel ASME XI, Category R-A weld, Item R1.20, High Safety Significant not subject to a degradation mechanism.
The weld configuration is stainless steel (ASTM 376, Type 316) pipe to a stainless steel valve (ASTM 351).
This new weld also received volumetric examination by radiography and a liquid penetrant surface examination for preservice with no unacceptable flaws or indications detected.
When the system reached operating pressure and temperature, the weld was further inspected visually (VT-2) for through-wall leaks with none detected.
Weld 1-19A Summary# S1.R1.20.096 Serial No.18-042 Docket No. 50-280 Page 4 of 9 This is a stainless steel ASME XI, Category R-A weld, Item R1.20, High Safety Significant not subject to a degradation mechanism. The weld configuration is a stainless steel valve (ASTM 351) to stainless steel pipe (ASTM 376, Type 316). This new weld also received volumetric examination by radiography and a liquid penetrant surface examination for preservice with no unacceptable flaws or indications detected.
When the system reached operating pressure and temperature, the weld was further inspected visually (VT-2) for through-wall leaks with none detected.
Table P01 Preservice Examinations Drawing / Line# / ID Pipe Op. Pressure Pipe Weld Coverage Limitation I System I Class/
Material
/Op.
Dia.
Thickness/
Achieved Results ASME Category Temperature Material 11448-WMKS-0125A1-2 Stainless 0.440" 50%
Single-
/ 4-RC-15 / 2-17B Steel 2235 psi 4"
Stainless sided, pipe Reactor Coolant/1 ASTM 376 543 °F Steel Type 20.75%
to valve, R-A Type 316 316 Best Effort NRI*
11448-WMKS-0125A1-2 Stainless 0.431 "
50%
/ 4-RC-15 / 2-18B Steel 2235 psi Stainless Single-Reactor Coolant/1 ASTM 376 543 °F 4"
Steel Type 20.75%
sided, valve R-A Type 316 316 Best Effort to pipe, NRI*
11448-WMKS-0125A1-1 Stainless 2235 psi 0.422" 50%
Single-
/ 4-RC-14 / 1-18A Steel Stainless sided, pipe Reactor Coolant/1 ASTM 376 543 °F 4"
Steel Type 12.5%
to valve, R-A Type 316 316 Best Effort NRI*
11448-WMKS-0125A1-1 Stainless 0.433" 50%
Single-
/ 4-RC-14 / 1-19A Steel 2235 psi 4"
Stainless sided, valve Reactor Coolant/1 ASTM 376 543 °F Steel Type 20.75%
to pipe, NRI*
R-A Type 316 316 Best Effort
- No recordable indications Fig.
1 2
3 4
5. Burden Caused by Compliance
Serial No.18-042 Docket No. 50-280 Page 5 of 9 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 option to rebuild components is considered impractical and would cause unnecessary personnel radiation exposure. Furthermore, plant equipment could be impacted in a detrimental manner.
6. Proposed Alternative and Basis for Use
The subject welds received a volumetric examination to the maximum extent practical utilizing the best available techniques. With the incorporation of the POI for Supplement 2, demonstration for best effort coverage was made for single-sided examination from the accessible side of the austenitic steel welds. The best effort coverage achieved is provided in Table P01. No indications were noted for any of the areas volumetrically examined. The four welds were surface examined using the liquid penetrant test achieving 100% coverage of the welds with no indications. The welds were volumetrically examined by radiography with no unacceptable flaws detected. Upon return to service the welds received visual examinations (VT-2) with no through-wall leakage detected.
The components are monitored for through-wall leakage as part of the ASME XI System Pressure Test Program and receive visual (VT-2) examinations every refueling outage as required by Section XI, IWB-2500-1 Category B-P for Class 1 components.
None of the pipe or weld material is constructed with Alloy 600/82/182 materials; therefore, there are no primary stress corrosion cracking (PWSCC) concerns.
Based on the volumetric coverage obtained by ultrasonic examination, the visual (VT-2) examinations performed upon return to service, the surface examinations (liquid penetrant) and full volumetric examination (radiography) all with acceptable results, it is reasonable to conclude that no unacceptable flaws exist in the new welds.
These proposed alternatives provide an acceptable level of quality and safety by providing reasonable assurance of structural integrity of the subject welds.
Dominion Energy Virginia requests relief in accordance with 10 CFR 50.55a(g)(5)(iii).
7. Duration of Proposed Alternative
This proposed alternative is requested to meet requirements for the fifth ten-year inspection interval for Surry Power Station Unit 1, which began December 14, 2013 and ends October 13, 2023.
Weld Number Thickness 2
PIPE 2-178 0.44" 0
2-178 CL
- ~
Serial No.18-042 Docket No. 50-280 Page 6 of 9 Report No: UT-15-002 Summary # Sl.Rl.091 Pg.
5 of 5
Date: 04/21/2015 Weld Width Weld Length FLOW 2
VALVE 0.65" 14.25" 0.825" WIDTH X.147 HT =0.12 SQ. IN. = REQUIRED VOLUME BOTH SIDES OF WELD EXAMINED 100% OF THE REQUIRED VOLUME US SIDE BEST EFFORT OS SIDE AX DIRECTION FOR 0.10 SQ. IN.
. 1/.12 = 0.83 X 100 = 83%
NO EXAM OS SIDE AX DIRECTION FOR 0.02 SQ. IN.
Examination Volume Dimensions -
Height 0.147" l ength 14.25" Width 1.65" Coverage Summary Required Scans (each has a weighing factor of 100 for complete coverage)
ANGLE UpSt-Ax UpSt-Circ DnSt-Ax DnSt-Circ 45, 60 100%
100%
0%
70 2.25 MHz
- s3%
Code Coverage Total I
50%
100+100+83+0=283/4=70.75
- sest Effort Coverage (Max 25%) Total I 20.75%
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 weld centerline that is examined in the axial beam direction with an Appendix VIII demonstrated procedure for single sided coverage.
Figure 1 Weld 2-178
Weld Number Thickness 2
2-188 PIPE 2-188 0.431" 0
CL 60,70 Report No: UT-15-005 Summary# Sl.Rl.20.092 Pg.
5 of 5
Date: 04/21/2015 Weld Width Weld Length 2
FLOW
--=
VALVE 0.70" 14.25" 0.85' WIDTH X 0.144" HT= 0.12 SQ. IN. = REQUIRED VOLUME BOTH SIDES OF WELD EXAMINED 100% OF THE REQUIRED VOLUME OS SIDE BEST EFFORT US SIDE AX DIRECTION FOR 0.10 SQ IN
.1/.12 = 0.83 X 100 = 83%
NO EXAM US SIDE AX DIRECTION FOR 0.02 SQ. INCHES Serial No.18-042 Docket No. 50-280 Page 7 of 9 Examination Volume Dimensions -
Height 0.144" Length 14.25" Width 1.7" Coverage Summary Required Scans (each has a weighing factor of 100 for complete coverage)
ANGLE UpSt-Ax UpSt-Circ DnSt-Ax DnSt-Circ 45, 60 0%
0%
100%
100%
70 2.25 MHZ
- 83%
Code Coverage Total I
50%
100+100+83+0=283/4=70.75
- Best Effort Coverage (Max 25%) Total I 20.75%
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 weld centerline that is examined in the axial beam direction with an Appendix VIII demonstrated procedure for single sided coverage.
Figure 2 Weld 2-18B
Report No: UT-15-127 Summary# Sl.Rl.20.095 Pg.
S of 5
Date: 05/10/2015 Serial No.18-042 Docket No. 50-280 Page 8 of 9 Weld Number Thickness 1-18A 0.422" Weld Width Weld Length 0.75" 14.25" 2
0 2
0.422" T I 3 = 0.141" FLOW 0.141" HT X.875 WIOlH =.12 SQ. IN = REQUIRED VOLUME BOTH SIDES OF WELD EXAMINED 0.06 SQ IN OS SIDE AX DIRECTION.06 /.12 = 0.5 X 100 = 50%
BE ST EFFORT= 50%
~
NO EXAM OS SIDE AX DIRECTION FOR 50% OF THE REQUIRED VOLUME Examination Volume Dimensions -
Height 0.141" l ength 14.25" Width 1.75" Coverage Summary Required Scans (each has a weighing facto r of 100 for complete coverage)
ANGLE UpSt-Ax UpSt-Circ DnSt-Ax DnSt-Circ 45,60 100%
100%
0%
70 2.25 Mhz
- SO%
Code Coverage Total I
50%
100+100+50+0=250/4=62.5
- Best Effort Coverage (Max 25%) Total I 12.5%
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 weld centerline that is examined in the axial beam direction with an Appendix VIII demonstrated procedure for single sided coverage.
Figure 3 Weld 1-18A
Weld Number Thickness 2
1-19A 0.433" 0
Report No: UT-15-006 Summary# Sl.Rl.20.096 Pg.
5 of 5
Dat e: 04/20/2015 Weld Width Weld Length 2
FLOW 0.65" 14.25" 0.825' WDTH X 0.144" HT = 0.12 SQ. IN. = REQUIRED VOLUME BOTH SIDE OF WELD EXAMINED 100% OF THE REQUIRED VOLUME DS SIDE BEST EFFORT US SIDE AX DIRECTION FOR 0.10 SQ IN.
. 1/.12 = 0.83 X 100 = 83%
NO EXAM US SIDE AX DIRECTION FOR 0.02 SQ. INCHES Examination Volume Dimensions -
Height 0.144" Length 14.25" Width 1.65" Coverage Summary Required Scans (each has a weighing factor of 100 for complete coverage)
ANGLE UpSt-Ax UpSt-Circ DnSt-Ax DnSt-Circ 45, 60 0%
0%
100%
100%
70 2.25 MHZ
- 83%
Code Coverage Total I
50%
Serial No.18-042 Docket No. 50-280 Page 9 of 9 I
100+100+83+0=283/4=70.75
- Best Effort Coverage (Max 25%} Total I 20.75%
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 weld centerline that is examined in the axial beam direction with an Appendix VIII demonstrated procedure for single sided coverage.
Figure 4 Weld 1-19A