ML050630558
| ML050630558 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 03/04/2005 |
| From: | Abney T Tennessee Valley Authority |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| Download: ML050630558 (40) | |
Text
March 4, 2005 10 CFR 50.55a(g)(5)
U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Mail Stop: OWFN P1-35 Washington, D.C. 20555-0001 Gentlemen:
In the Matter of )
Docket No. 50-296 Tennessee Valley Authority )
BROWNS FERRY NUCLEAR PLANT (BFN) - UNIT 3 - AMERICAN SOCIETY OF MECHANICAL ENGINEERS (ASME) SECTION XI, INSERVICE INSPECTION (ISI) PROGRAM, SECOND TEN-YEAR INSPECTION INTERVAL - REQUESTS FOR RELIEF 3-ISI-7, REVISION 1, 3-ISI-12, AND 3-ISI-19 In accordance with 10 CFR 50.55a(g)(5) TVA is requesting relief from certain inservice inspection requirements in Section XI of the ASME Boiler and Pressure Vessel Code. This letter submits BFN Unit 3 requests for relief 3-ISI-7, Revision 1, 3-ISI-12, and 3-ISI-19 for NRC review and approval.
Request for relief 3-ISI-7, Revision 1, addresses ten (10)
Reactor Pressure Vessel (RPV) nozzle-to-vessel full penetration welds and one (1) nozzle inner radius weld. The design configuration of the RPV nozzle-to-vessel and inner-radius welds precludes a 100 percent ultrasonic (UT) examination of the required volume for the full penetration welds of the nozzles.
Request for relief 3-ISI-12 addresses three Residual Heat Removal System, and one Reactor Water Cleanup System full penetration austenitic stainless steel piping welds. An ultrasonic examination was performed for these piping welds of the accessible areas, to the maximum extent practical, due to the configuration. Credit for the one-sided only ultrasonic examination provided 50 percent coverage because of recently added requirement in 10 CFR 50.55a(a)(b)(2)(xv)(2), which
U.S. Nuclear Regulatory Commission Page 2 March 4, 2005 states in part, "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 flaw on the opposite side of the weld..." At this time, there is no Appendix VIII Program for single sided austenitic welds nor is one planned in the future; therefore, only 50 percent coverage can be claimed.
Under the original ASME Section XI Code requirements [prior to 10 CFR 50.55a(a)(b)(2)(xv)(2)], UT coverage attained was 100 percent.
Request for relief 3-ISI-19 addresses three reactor pressure vessel (RPV) longitudinal shell welds. These RPV shell welds did not receive essentially (i.e., greater than 90 percent) 100 percent coverage due to obstructions from other components.
of this letter contains 3-ISI-7, Revision 1. Request for relief, 3-ISI-12 is provided in enclosure 2. Additionally, enclosure 3 provides 3-ISI-19.
TVA requests approval of these requests for relief by November 18, 2005, which is the end of second ten-year inspection interval for Unit 3.
There are no new regulatory commitments in this letter. If you have any questions, please contact me at (256) 729-2636.
Sincerely, Original signed by:
T. E. Abney Manager of Licensing and Industry Affairs cc: See Page 3
U.S. Nuclear Regulatory Commission Page 3 March 4, 2005 Enclosures cc (Enclosures):
(Via NRC Electronic Distribution)
Mr. Stephen J. Cahill, Branch Chief U.S. Nuclear Regulatory Commission Region II Sam Nunn Atlanta Federal Center 61 Forsyth Street, SW, Suite 23T85 Atlanta, Georgia 30303-8931 NRC Resident Inspector Browns Ferry Nuclear Plant 10833 Shaw Road Athens, Alabama 35611-6970 Ms. Eva A. Brown, Project Manager U.S. Nuclear Regulatory Commission One White Flint, North (MS 08G9) 11555 Rockville Pike Rockville, Maryland 20852-2739 Ms. Margaret Chernoff, Project Manager U.S. Nuclear Regulatory Commission One White Flint, North (MS 08G9) 11555 Rockville Pike Rockville, Maryland 20852-2739
U.S. Nuclear Regulatory Commission Page 4 March 4, 2005 DTL:JWD:BAB Enclosures cc (Enclosures):
A. S. Bhatnagar, LP 6A-C Samuel Flood, PMB 2A-BFN J. C. Fornicola, LP 6A-C D. F. Helms, BR 4T-C R. G. Jones, NAB 1A-BFN K. L. Krueger, POB 2C-BFN R. F. Marks, PAB 1C-BFN N. M. Moon, LP 6A-C F. C. Mashburn, BR 4X-C J. R. Rupert, NAB 1A-BFN K. W. Singer, LP 6A-C M. D. Skaggs, PAB 1E-BFN E. J. Vigluicci, ET 11A-K NSRB Support, LP 5M-C EDMS WT CA-K s:\\lic\\everyone\\Unit 3 RFR 3-ISI-7, 3-ISI-12, 3-ISI-19.doc
ENCLOSURE 1 TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)
UNIT 3 AMERICAN SOCIETY OF MECHANICAL ENGINEERS (ASME) SECTION XI, INSERVICE INSPECTION (ISI) PROGRAM (SECOND TEN-YEAR INSPECTION INTERVAL)
REQUEST FOR RELIEF 3-ISI-7, REVISION 1 (SEE ATTACHED)
E1-2 TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)
UNIT 3 AMERICAN SOCIETY OF MECHANICAL ENGINEERS (ASME) SECTION XI, INSERVICE INSPECTION (ISI) PROGRAM (SECOND TEN-YEAR INSPECTION INTERVAL)
REQUEST FOR RELIEF 3-ISI-7, REVISION 1 Executive Summary:
This request for relief addresses ten (10)
Reactor Pressure Vessel (RPV) nozzle-to-vessel full penetration welds and one (1) nozzle inner radius weld. The design configuration of the RPV nozzle-to-vessel and inner-radius welds precludes a 100 percent ultrasonic (UT) examination of the required volume for the full penetration welds of the nozzles listed in Table 1.
These examination limitations occur when the ASME Section XI, 1989 Edition, no addenda, examination requirements are applied in areas of components constructed and fabricated to early plant designs.
Based on a construction permit date prior to January 1, 1971, BFN is exempt from meeting certain provisions of the code requirements for examination access, to the extent practical, within the limitations of design, geometry, and materials of construction of the components in accordance with 10 CFR 50.55a(g)(4).
A UT examination was performed on accessible areas of the subject welds to the maximum extent practical, given the physical limitations of the subject welds. The subject welds were examined with the latest ultrasonic techniques, procedures, equipment, and personnel qualified to the requirements of the Performance Demonstration Initiative (PDI) Program, as mandated by 10 CFR 50.55a(g)(4). The design configuration limits UT examination of the RPV nozzle-to-vessel weld coverage (percentage) to that shown in Table 1.
TVA has determined that performance of an UT examination of essentially 100 percent of the RPV nozzle-to-vessel full penetration
E1-3 welds would be impractical. The performance of the UT examination of the subject areas, to the maximum extent practical, provides an acceptable level of quality and safety because the information and data obtained from the volume examined provides sufficient information to judge the overall integrity of the welds. Therefore, pursuant to 10 CFR 50.55a(g)(5)(iii), TVA requests that relief be granted for the second ten-year inspection interval (November 19, 1996 to November 18, 2005).
Unit:
Three (3)
System:
Reactor Pressure Vessel (RPV) (System 329)
Components:
10 RPV Nozzle full penetration welds, and 1 Nozzle inner radius exam area, as listed in Table 1 ASME Code Class:
ASME Code Class 1 (Equivalent)
Section XI Edition:
1989 Edition, no addenda Note: The Code of Record for the BFN Unit 3 Second Ten-Year ISI Interval is the 1989 Edition, with no Addenda for component selection. However, TVA has adopted the 1995 Edition with the 1996 addenda (all TVA nuclear sites) for performance of nondestructive examinations.
Code Table:
IWB-2500-1 Examination Category:
B-D, Full Penetration Welds of Nozzles in Vessels Examination Item Number:
B3.90, Reactor Vessel Nozzle-to-Vessel Welds, and B3.100, Reactor Vessel Nozzle Inside Radius Section Code Requirement:
ASME Section XI, Table IWB-2500-1, Examination Category B-D, Item No. B3.90 requires a volumetric examination of essentially 100 percent of the weld and adjacent base material as depicted in Figure IWB-2500-7(a).
ASME Section XI, Table IWB-2500-1, Examination Category B-D, Item No. B3.100
E1-4 requires a volumetric examination of essentially 100 percent of the nozzle inner radius area as depicted in Figure IWB-2500-7(a).
Code Requirements From Which Relief Is Requested:
Relief is requested from the requirement of ASME Section XI Code, Table IWB-2500-1, Examination Category B-D, Item No. B3.90 to perform essentially 100 percent volumetric examination of weld and adjacent base material and Item No. B3.100 to perform essentially 100 percent volumetric examination of the nozzle inner radius area.
List Of Items Associated With The Relief Request:
N1B RPV Nozzle-to-Vessel Weld N2A RPV Nozzle-to-Vessel Weld N2C RPV Nozzle-to-Vessel Weld N2E RPV Nozzle-to-Vessel Weld N3A RPV Vessel-to-Nozzle Weld N4A RPV Nozzle-to-Vessel Weld N4F RPV Nozzle-to-Vessel Weld N5B RPV Nozzle-to-Vessel Weld N9 RPV Nozzle-to-Vessel Weld N7 RPV Nozzle-to-Vessel Weld N10 RPV (Standby Liquid control)
Nozzle Inner Radius Basis For Relief:
The design configuration of the RPV nozzle-to-vessel welds and the Standby Liquid Control nozzle inner radius area precludes an UT examination of essentially 100 percent of the required volume. The component design configuration limits UT examination coverage of the welds to the percentages listed in Table 1.
Alternative Examination:
None. In lieu of the Code required essentially 100 percent volume UT examination, TVA proposes a UT examination of the accessible areas, to the maximum extent practical, given the component design configuration of the RPV nozzle-to-vessel welds and the Standby Liquid Control Nozzle inner radius.
E1-5 Justification for The Granting of Relief:
(1) The design configuration of the subject nozzle-to-vessel welds precludes UT examination of essentially 100 percent of the required examination volume.
Access to the nozzle-to-vessel welds is by a series of doorways in the concrete biological shield wall. Insulation behind these doorways is designed for removal around the nozzle circumference. In order to examine the welds in accordance with the code requirements the RPV would require extensive design modifications.
The physical arrangements of the nozzle-to-vessel welds precludes UT examination from the nozzle side. The limitations are inherent to the barrel-type nozzle-to-vessel weld design and are compounded by the close proximity of the biological shield wall.
Scanning from the nozzle surface is ineffective due to the weld location and the asymmetrical inside surface where the nozzle and vessel converge. Coverage was increased by scanning from the outside blend radius of the weld where practical.
The small blend radius of the N10 nozzle configuration prevents 100 percent coverage from the blend area. Experience from the automated UT examination performed from the inside surface has shown that the nozzle-to-vessel weld coverage will not be greatly improved even if performed from the inside surface utilizing the current state-of-the-art techniques.
The configuration of the nozzle-to-vessel welds precludes UT examination from the nozzle side due to the weld location and the asymmetrical inside surface where the nozzle and vessel converge. The extent of examination coverage from the vessel side provides reasonable assurance that no flaws oriented parallel to the weld are present.
The areas receiving little or no examination coverage are located toward the outside surface of the reactor vessel in the general area of the nozzle outside blend radius. (The blend radius restricts the scanning movement and/or transducer
E1-6 contact). The reactor vessel inner-half of the thickness and inside surface are interrogated with the UT beam. Degradation located at the inside surface or inner-half of the vessel would be located. It should be noted that the nozzle inside radius section, with the exception of N-10 IR, received essentially 100 percent examination coverage.
The Standby Liquid Control nozzle, N-10, is designed with an integral socket to which the boron injection piping is welded. This integral socket area is included in the exam boundary as indicated in ASME Section XI, Figure IWB-2500-7. The nozzle location, below the core support plate, prevents examination form the vessel interior; therefore, the exam must be performed from the vessel outside surface of the vessel head. Because of the small diameter of the nozzle (i.e., ~ 2 inches) and the thickness of the head (i.e., ~ 6 inches), the ratio of the nozzle diameter to the head thickness make it impractical to perform an examination from the nozzle-to-head radius blend surface.
Also, to perform the ultrasonic examination from the head surface, the sound must travel through the full thickness of the head into a complex cladding/socket configuration.
The geometric configuration inherent to the design prevent 100 percent coverage from being achieved on the inside radius section of the nozzle. The subject welds were examined with the latest ultrasonic techniques, procedures, equipment, and personnel qualified to the requirements of the Performance Demonstration Initiative (PDI) Program, in accordance with the requirements of the 1995 Edition, 1996, Addenda of ASME Section XI, Division 1, Appendix VIII, as mandated by 10 CFR 50.55a(g)(4).
(2) Radiographic examination as an alternate volumetric examination method was determined to be impractical due the radiological concerns. Gaining access to the inside surface of the RPV to place radiographic film would require extensive personnel protection due to high radiation and contamination levels. Also, due to the varying thickness at the outside blend
E1-7 radius of the weld several radiographs may be required of one area to obtain the required coverage and/or film density.
The additional Code coverage gained by radiography is impractical when weighed against the radiological concerns.
Therefore, TVA concludes that performing an UT examination of essentially 100 percent of the nozzle-to-vessel full penetration welds, and the Standby Liquid Control Nozzle inner radius area in the RPV would be impractical. Further, it would also be impractical to perform other volumetric examinations (i.e., radiography) which may increase examination coverage. A maximum extent practical UT examination of the subject areas provides an acceptable level of quality and safety. TVA concludes that significant degradation, if present, would be detected during an UT examination performed to the maximum extent practical of the subject welds. As a result, reasonable assurance of operational readiness of the subject welds has been provided.
(3) Reference previously submitted TVA request for relief 3-ISI-7, Revision 0, dated March 26, 1999, and approved by NRC SER dated August 2, 1999. The items associated with that request for relief are as follows:
N1A - RPV Nozzle-to-Vessel Weld N2B - RPV Nozzle-to-Vessel Weld N2D - RPV Nozzle-to-Vessel Weld N2F - RPV Nozzle-to-Vessel Weld N3B - RPV Nozzle-to-Vessel Weld N4B - RPV Nozzle-to-Vessel Weld N4C - RPV Nozzle-to-Vessel Weld N5A - RPV Nozzle-to-Vessel Weld N8A - RPV Nozzle-to-Vessel Weld Implementation Schedule:
This request for relief is applicable to the second ten-year inspection interval for BFN Unit 3. The nozzle-to-vessel welds listed in Table 1 were examined in the second period (Cycle 10) and the N10-IR in the third period (Cycle 11) of the second ten-year inspection interval (November 19, 1996 to November 18, 2005).
E1-8 Attachments:
Attachment A - 6 sketches Sketch SK-B3001, Reactor Pressure Vessel Assembly Sketch SK-B3017, N1 Recirculation Nozzles Sketch SK-B3018, N2 Recirculation Inlet, N3 Main Steam, N4 Feedwater, and N5 Core Spray Nozzles Sketch SK-B3015, N7, Reactor Pressure Vessel Head Vent Nozzle Sketch SK-B3020, N9, Control Rod Drive Return Line Nozzle Sketch SK-B3022, N10, Reactor Pressure Standby Liquid Control Nozzle
TABLE 1 WELD NUMBERS NPS Cycle ISI DRAWING PERCENT COVERAGE Remarks NIB N/V (Recirc Outlet) 28 10 3-ISI-0328-C 77%*
No transverse scans were performed from the nozzle side N2A N/V (Recirc Inlet) 12 10 3-ISI-0328-C 77%*
No transverse scans were Performed from the nozzle side N2C N/V (Recirc Inlet) 12 10 3-ISI-0328-C 77%*
No transverse scans were performed from the nozzle side N2E N/V (Recirc Inlet) 12 10 3-ISI-0328-C 77%*
No transverse scans were performed from the nozzle side N3A N/V (Main Steam) 26" 10 3-ISI-0329-C 77%*
No transverse scans were performed from the nozzle side N4A N/V (Feedwater) 12" 10 3-ISI-0327-C 77%*
No transverse scans were Performed from the nozzle side N4F N/V (Feedwater) 12" 10 3-ISI-0327-C 77%*
No transverse scans were performed from the nozzle side N5B N/V (Core Spray) 10" 10 3-ISI-0220-C 71%*
No transverse scans were Performed from the nozzle side N9 N/V (CRD Control) 4" 10 3-ISI-0220-C 74%*
No transverse scans were performed from the nozzle side
E1-10 N7 N/V (Vent) 4" 10 3-ISI-0295-A 70%*
No transverse scans were performed from the nozzle side N10 Inner Radius (Standby Liquid Control) 2 11 3-ISI-0445-C 90%
No scans were performed from the nozzle to head blend area.
E1-11
- These exams were performed during the Unit 3, Cycle 10 Refueling Outage, and were conducted prior to issuance of NRC Letter from Terence L. Chan to Randy T. Linden dated December 5, 2003, subject: Nozzle-to-reactor vessel weld coverage issues. This letter documents the NRC position that the maximum achievable coverage of 10 CFR 50.55a(b)(2)(xv)(K) is acceptable when the coverage of 10 CFR 50.55a(b)(2)(xv)(G) is not achievable. The application of this issue was applied to nozzle-to-reactor vessel weld examinations conducted in Unit 3, Cycle 11 Refueling Outage, resulting in achieved coverage greater than 90 percent..
E1-12 Attachment A Six (6) Sketches Sketch SK-B3001, Reactor Pressure Vessel Assembly Sketch SK-B3017, N1 Recirculation Nozzles Sketch SK-B3018, N2 Recirculation Inlet, N3 Main Steam, N4 Feedwater, and N5 Core Spray Nozzles Sketch SK-B3015, N7, Reactor Pressure Vessel Head Vent Nozzle Sketch SK-B3020, N9, Control Rod Drive Return Line Nozzle Sketch SK-B3022, N10, Reactor Pressure Vessel Standby Liquid Control Nozzle
E1-13 SK-B3001
E1-14 SK-B3017
E1-15 SK-B3018
E1-16 SK-B3015
E1-17 SK-B3020
E1-18 SK-B3022
ENCLOSURE 2 TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)
UNIT 3 AMERICAN SOCIETY OF MECHANICAL ENGINEERS (ASME) SECTION XI, INSERVICE INSPECTION (ISI) PROGRAM (SECOND TEN-YEAR INSPECTION INTERVAL)
REQUEST FOR RELIEF 3-ISI-12 (SEE ATTACHED)
E2-2 TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)
UNIT 3 AMERICAN SOCIETY OF MECHANICAL ENGINEERS (ASME) SECTION XI, INSERVICE INSPECTION (ISI) PROGRAM (SECOND TEN-YEAR INSPECTION INTERVAL)
REQUEST FOR RELIEF 3-ISI-12 Executive Summary:
This request for relief addresses one (1)
Reactor Water Clean Up (RWCU) System and three (3) Residual Heat Removal (RHR)
System Full Penetration Piping Welds examined in Cycle 10 and Cycle 11 of the second and third period of the second ten-year interval.
The subject welds were examined with the latest ultrasonic techniques, procedures, equipment, and personnel qualified to the requirements of the Performance Demonstration Initiative (PDI) Program, as mandated by 10 CFR 50.55a(g)(4).
An ultrasonic examination was performed on these piping welds of the accessible areas, to the maximum extent practical.
Credit for the one-sided only ultrasonic examination provided 50 percent coverage because of a requirement mandated in 10 CFR 50.55a(a)(b)(2)(xv)(2), which states in part, "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 flaw on the opposite side of the weld..." Therefore only 50 percent coverage can be claimed (re: RHR system welds DRHR-3-19 and DRHR-3-21).
Additionally, there is no Appendix VIII Program for cast austenitic piping welds; therefore, only 50 percent coverage can be claimed (re: RHR system weld TRHR-3-191 and RWCU system weld RWCU 3-007-G004).
Prior to the 10 CFR 50.55a(a)(b)(2)(xv)(2) rule change, ASME Section XI Code UT coverage attained would have been 100 percent.
E2-3 The performance of the ultrasonic examination of the subject areas, to the maximum extent practical, provides an acceptable level of quality and safety because the information and data obtained from the volume examined provides sufficient information to judge the overall integrity of the piping welds.
Therefore, pursuant to 10 CFR 50.55a(g)(5)(iii), TVA requests that relief be granted for the second ten-year inspection interval (November 19, 1996 to November 18, 2005).
Unit:
Three (3)
System:
Residual Heat Removal System (RHR)
(3 welds), and Reactor Water Clean Up System (RWCU) (1 weld)
Components:
4 Full Penetration Piping Welds ASME Code Class:
ASME Code Class 1 Section XI Edition:
1989 Edition, no Addenda Note: The Code of Record for the BFN Unit 3 Second Ten-Year ISI Interval is the 1989 Edition, with no Addenda for component selection. However, TVA has adopted the 1995 Edition with the 1996 addenda (all TVA nuclear sites) for performance of nondestructive examinations.
Code Table:
Code Case N-577, N-577-2500 Table I Examination Category:
R-A, Risk - Informed Piping Examinations Examination Item Number: R1.16, Elements Subject to Intergranular Stress Corrosion Cracking (IGSCC) and R1.11, Elements Subject to Thermal Fatigue.
Code Requirement:
Code Case N-577, N-577-2500, Table I, Examination Category R1.11 and R1.16, Requires Volumetric Examination of 100 percent of the Weld and Adjacent Base Material as depicted in Figure
E2-4 IWB-2500-8(c). Additionally, the exam volume for Category R1.11 is expanded to include the area 1/2 beyond each side of the base material thickness transition or counterbore.
Code Requirement From Which Relief Is Requested:
Relief is requested from the Risk-Informed Inservice Inspection Program, Code Case N-577 requirement (Table I N-577-2500) Examination Category R-A, Item No. R1.16, Elements Subject to Intergranular Stress Corrosion Cracking (IGSCC)), to perform essentially (i.e.,
greater than 90 percent) 100 percent volumetric examination of weld and adjacent base material. Relief is requested from the Risk-Informed Inservice Inspection Program, Code Case N-577 requirement (Table I, N-577-2500)
Examination Category R-A, Item No. R1.11, Elements Subject to Thermal Fatigue, to perform essentially (i.e., greater than 90 percent) 100 percent volumetric examination of weld and adjacent base material.
List Of Items Associated With The Relief Request:
DRHR-3-19, Tee to Pipe Weld (Unit 3 Cycle 11)
DRHR-3-21, Elbow to Pipe Weld (Unit 3 Cycle 10)
TRHR-3-191, Valve to Elbow Weld (Unit 3 Cycle 11)
RWCU-3-007-G004, Pipe to Valve Weld (Unit 3 Cycle 11)
Basis for Relief:
It is not possible to perform the volumetric ultrasonic examination from both sides of the weld due to the configuration of these components. Also, because of the requirement mandated in 10 CFR 50.55a(a)(b)(2)(XV)(2), which states in part, "Where examination from both sides is not possible on austenitic welds, full coverage credit from a single
E2-5 side may be claimed only after completing a successful single-sided Appendix VIII demonstration using flaw on the opposite side of the weld..." Additionally, there is no Appendix VIII Program for cast austenitic piping welds; therefore, only 50 percent coverage can be claimed. Prior to the 10 CFR 50.55a(a)(b)(2)(xv)(2) rule change, ASME Section XI Code UT coverage attained would have been 100 percent.
Weld DRHR-3-19 limitations were due to the configuration of the component, Tee to Pipe.
Weld DRHR-3-21 limitations were due to the configuration of the component, Elbow to Pipe.
Weld TRHR-3-191 limitations were due to the configuration of the component, Cast Austenitic Valve to Elbow.
Weld RWCU-3-007-G004 limitations were due to the configuration of the component, Pipe to Cast Austenitic Valve.
The performance of the ultrasonic examination of the subject areas, to the maximum extent practical, provides an acceptable level of quality and safety because the information and data obtained from the volume examined provides sufficient information to judge the overall integrity of the piping welds.
A detailed description of the examination limitations is provided in Table 1.
Alternative Examination:
None. In lieu of the Code required essentially 100 percent (i.e., greater than 90 percent) volume ultrasonic examination, TVA proposes an ultrasonic examination of accessible areas, to the maximum extent practical, given the component design configuration of the aforementioned piping welds.
Justification For The Granting Of Relief: The welds were examined with the latest ultrasonic techniques, procedures, equipment, and personnel qualified to
E2-6 the requirements of the Performance Demonstration Initiative (PDI) Program, in accordance with the requirements of the 1995 Edition, 1996, Addenda of ASME Section XI, Division 1, Appendix VIII as mandated by 10 CFR 50.55a(g)(4).
An ultrasonic examination was performed on the piping welds of the accessible areas, to the maximum extent practical, due to the configuration. Credit for the one-sided only ultrasonic examination provided 50 percent coverage because of a new requirement mandated in 10 CFR 50.55a(a)(b)(2)(XV)(2), which states in part, "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 flaw on the opposite side of the weld..." Additionally, there is no Appendix VIII Program for cast austenitic piping welds; therefore, only 50 percent coverage can be claimed. Under the original ASME Section XI Code requirements UT coverage attained was 100 percent.
Weld DRHR-3-19 limitations were due the configuration of the component, Tee to Pipe weld.
Weld DRHR-3-21 limitations were due the configuration of the component, Elbow to Pipe weld.
Weld TRHR-3-191 limitations were due the configuration of the component, Cast Austenitic Valve to Elbow weld.
Weld RWCU-3-007-G004 limitations were due the configuration of the component, Pipe to Cast Austenitic Valve weld.
The performance of the ultrasonic examination of the subject areas, to the maximum extent practical, provides an acceptable level of quality and safety because the information and data obtained from the volume examined provides sufficient information to judge the overall integrity of the piping welds.
E2-7 Therefore, pursuant to 10 CFR 50.55a(g)(5)(iii), TVA requests that relief be granted for the second ten-year inspection interval (November 19, 1996 to November 18, 2005).
Implementation Schedule:
This request for relief is applicable to the second ten-year inspection interval for BFN Unit 3. The welds listed in Table 1 were examined during the second period (Cycle 10) and the third period (Cycle 11) of the second ten year inspection interval.
E2-8 TABLE 1 WELD NUMBERS NPS ISI DRAWING PERCENT UNIT/CYCLE REMARKS DRHR-3-19 20" 3-ISI-0330-C 50%
3/11 Limitations due to component configuration and the new requirement in 10 CFR 50.55a (a)(b)(2)(xv)(2), which requires UT of one-side of austenitic welds to be qualified to Appendix VIII Program to claim full code coverage. At this time, there are no Appendix VIII Program for single sided austenitic welds nor is one planned for the future; therefore, only 50% coverage can be claimed.
DRHR-3-21 20" 3-ISI-0330-C 50%
3/10 Limitations due to component configuration and the new requirement in 10 CFR 50.55a (a)(b)(2)(xv)(2), which requires UT of one-side of austenitic welds to be qualified to Appendix VIII Program to claim full code coverage. At this time, there are no Appendix VIII Program for single sided austenitic welds nor is one planned for the future; therefore, only 50% coverage can be claimed.
TRHR-3-191 20 3-ISI-0330-C 50%
3/11 Limitations due to component configuration and the new requirement in 10 CFR 50.55a (a)(b)(2)(xv)(2), which requires UT of one-side of austenitic welds to be qualified to Appendix VIII Program to claim full code coverage. At this time, there are no Appendix VIII Program for single sided austenitic welds nor is one planned for the future; therefore, only 50% coverage can be claimed.
E2-9 WELD NUMBERS RWCU-3-007-G004 NPS 4
ISI DRAWING 3-ISI-0332-C PERCENT 50%
UNIT/CYCLE 3/11 REMARKS Limitations due to component configuration and the new requirement in 10 CFR 50.55a (a)(b)(2)(xv)(2), which requires UT of one-side of austenitic welds to be qualified to Appendix VIII Program to claim full code coverage. At this time, there are no Appendix VIII Program for single sided austenitic welds nor is one planned for the future; therefore, only 50% coverage can be claimed.
ENCLOSURE 3 TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)
UNIT 3 AMERICAN SOCIETY OF MECHANICAL ENGINEERS (ASME) SECTION XI, INSERVICE INSPECTION (ISI) PROGRAM (SECOND TEN-YEAR INSPECTION INTERVAL)
REQUEST FOR RELIEF 3-ISI-19 (SEE ATTACHED)
E3-2 TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)
UNIT 3 AMERICAN SOCIETY OF MECHANICAL ENGINEERS (ASME) SECTION XI, INSERVICE INSPECTION (ISI) PROGRAM (SECOND TEN-YEAR INSPECTION INTERVAL)
REQUEST FOR RELIEF 3-ISI-19 Executive Summary:
TVA is requesting relief from specified inservice inspection requirements in the 1989 Edition, no addenda,Section XI of the ASME Boiler and Pressure Vessel Code for Category B-A, Pressure Retaining Welds in Reactor Vessels (RPV), Item Number B1.12, Longitudinal Shell Welds. The requirement is for a volumetric examination of essentially 100 percent of the weld. The configuration of the BFN Unit 3 RPV and vessel internals prevents essentially 100 percent examination coverage of the three longitudinal shell welds (V-1-A, V-1-B, and V-1-C). BFN Unit 3 has fifteen longitudinal welds in the RPV shell courses. Three of the fifteen welds did not receive essentially 100 percent coverage because of obstructions from other components.
The physical examination limitations occur when the 1989 ASME Section XI Code examination requirements are applied in areas of components constructed and fabricated to early plant designs, which were not required to be designed for access. The BFN Unit 3 construction permit was issued prior to January 1, 1971, (July 31, 1968), and is therefore, exempt from complying with certain provisions of the Code requirements for examination access pursuant to 10 CFR 50.55a(g)(4).
Compliance with the 1989 Edition, no Addenda, of ASME Section XI, is impractical and will result in unusual difficulty and unnecessary radiation exposure to examination personnel without any compensating increase in the level of quality or safety.
E3-3 Therefore, pursuant to 10 CFR 50.55a(g)(5)(iii), TVA requests that relief be granted for the three welds described above for the second ten-year inspection interval (November 19, 1996 to November 18, 2005).
This request for relief is consistent with one submitted by TVA for BFN Unit 2, second ten-year inspection interval by letter dated May 24, 2002. The request was approved by NRC letter dated April 03, 2003.
Unit:
Three (3)
ISI Interval:
ASME Section XI, Second Ten-Year ISI Interval (November 19, 1996 to November 18, 2005)
System(s):
Components:
3 RPV Longitudinal Welds ASME Code Class:
ASME Code Class 1 ASME Section XI Code Edition:
1989 Edition, no Addenda Note: The Code of Record for the BFN Unit 3 Second Ten-Year ISI Interval is the 1989 Edition, with no Addenda for component selection. However, TVA has adopted the 1995 Edition with the 1996 addenda (all TVA nuclear sites) for performance of nondestructive examinations.
Code Table:
IWB-2500-1 Examination Category:
B-A, Pressure Retaining Welds in Reactor Vessel Examination Item Number:
B1.12 Longitudinal Shell Welds Code Requirement:
The 1989 Edition, no Addenda, ASME Section XI, Table IWB-2500-1, Examination Category B-A, Item Numbers B1.12 requires a volumetric examination of essentially 100 percent of the weld.
E3-4 Code Requirements From Which Relief Is Requested:
Relief is requested from the requirement to perform a volumetric examination of essentially (i.e., greater than 90 percent) 100 percent of the three RPV longitudinal shell welds.
List Of Items Associated With The Relief Request: Three (3) RPV Longitudinal Shell Welds, V-1-A, V-1-B, and V-1-C Basis For Relief Request:
Areas of the V-1-A, V-1-B, and V-1-C welds are inaccessible for UT examination due to the design configuration of the RPV and vessel internals. The examinations were performed with automated ultrasonic equipment from the vessel inside surface utilizing the Advanced Inservice Reactor Inspection System 21 device, (AIRIS 21) and Enhanced Data Acquisition System-II equipment (EDAS'-II). The V-1-A, V-1-B, and V-1-C RPV longitudinal shell weld scans were obstructed by a jet pump restrainer bracket and jet pump diffuser.
Alternative Examination:
None. In lieu of the Code required essentially (i.e., greater than 90 percent) 100 percent volume ultrasonic examination, TVA proposes an ultrasonic examination of accessible areas, to the maximum extent practical, given the component design, and configuration of the subject welds.
Justification for The Granting of Relief:
The configuration of BFN Unit 3 RPV and vessel internals prevents essentially 100 percent examination coverage of the three RPV longitudinal shell welds (V-1-A, V-1-B, and V-1-C). The examinations were performed with automated ultrasonic equipment from the vessel inside surface utilizing the Advanced Inservice Reactor Inspection System 21 (AIRIS 21) device, and Enhanced Data Acquisition System-II (EDAS'-II) equipment.
To increase the examination coverage of the shell-to-flange weld, manual UT examinations
E3-5 were performed on the outside surfaces of the RPV in areas of non-coverage from the inside surface examination. The manual examination also encountered scan limitations due to the flange configuration.
BFN Unit 3 has fifteen longitudinal welds in the RPV shell courses. Twelve of these welds received essentially (i.e., greater than 90 percent) 100 percent coverage.
Three of the fifteen welds did not receive essentially 100 percent coverage due to obstructions from the vessel internal components.
The V-1-A, V-1-B, and V-1-C longitudinal shell weld scans were obstructed by the jet pump restrainer bracket and jet pump diffuser and received 90, 86, and 89, percent coverage respectively. The outside surfaces of these three welds were inaccessible due to the concrete bio-shield wall.
The UT examinations of the longitudinal shell welds were performed to the maximum extent practical for maximum coverage. The UT examinations of the longitudinal shell welds were performed with equipment, personnel, and procedures qualified to the Performance Demonstration Initiative (PDI)
Program in accordance with the requirements of the 1995 Edition, 1996, Addenda of ASME Section XI, Division 1, Appendix VIII as mandated by 10 CFR 50.55a(g)(4).
Since BFN construction permit was issued prior to January 1, 1971, (July 31, 1968),
BFN is exempt from complying with certain provisions of the Code requirements for examination access as granted by 10 CFR 50.55a(g)(4).
Compliance with the 1989 Edition, no Addenda, ASME Section XI is not practical and will result in unusual difficulty and unnecessary radiation exposure to examination personnel without any compensating increase in the level of quality or safety. TVA considers that the obtained coverage, to the maximum extent practical, will provide an acceptable level of quality and safety.
E3-6 Implementation Schedule:
This request for relief is applicable to the BFN Unit 3, ASME Section XI, Second Ten-Year Inservice Inspection Interval (November 19, 1996 to November 18, 2005).
Attachment:
Sketches:
3-ISI-0220-C-01 3-ISI-0220-C-02
E3-7 Attachment 3-ISI-19 Two (2) Sketches 3-ISI-0220-C-01 3-ISI-0220-C-02
E3-8 3-ISI-0220-C-01
E3-9 3-ISI-0220-C-02