ML20203A488
| ML20203A488 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 02/03/1999 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20203A479 | List: |
| References | |
| NUDOCS 9902100015 | |
| Download: ML20203A488 (14) | |
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i SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION l OF REQUESTS FOR RELIEF NOS. B-3 THROUGH B-6. C-2. AND C-3 FOR COMANCHE PEAK STEAM ELECTRIC STATION. UNIT 2 TEXAS UTILITIES ELECTRIC STATION
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DOCKET NO. 50-446
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1.0 INTRODUCTION
L Inservice inspection of the American Society of Mechanical Engineers (ASME) Code Class 1, 2, and 3 components shall be performed in accordance with Section XI of the ASME Boiler and
. Pressure Vessel (B&PV) Code and applicable addenda as required by 10 CFR 50.55a(g),
except where specific relief has been granted by the Commission pursuant to 10 CFR 50.55a(6)(g)(i).10 CFR 50.55a(a)(3) states that altematives to the requirements of paragraph (g) may be used, when authorized by the Nuclear Regulator Commission, if (i) the proposed alternatives would provide an acceptable level of quality and safety or (ii) compliance with the !
specified requirements would result in hardship or unusual difficulty without a compensating . ;
' increase in the level of quality and safety.
Pursuant to .10 CFR 50.55a(g)(4), ASME Code Class 1,2, and 3 components (including supports) shall meet the requirements, except the' design and access provisions and the pre-
.. service examination requirements, set forth in the ASME Code,Section XI, " Rules for Inservice Inspection of Nuclear Power Plant Components,"_ to the extent practical within the limitations of design, geometry, and materials of construction of the components. The regulations require that inservice examination of components and system pressure tests conducted during the first
. ten year interval and subsequent intervals comply with the requirements in the latest edition and addenda of Section XI of the ASME Code incorporated by reference in 10 CFR 50.55a(b) t twelve months prior _ to the start of the 120-month interval, subject to the limitations and
, modifications listed therein. The Code of record for Comanche Peak Steam Electric Station s (CPSES), Unit 2 is the 1986 Edition.
4 2.0 EVALUATION By letters dated July 23,1996 (TXX-96426), and March 5,1998 (TXX-98058), Texas Utilities Electric company (licensee) submitted its First Ten-Year interval inservice Inspection Program Plan Requests for Relief Nos. B-3 through B-6, C-2, and C-3 for CPSES, Unit 2.
f- ENCLOSURE
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I The Idaho National Engineering and Environmental Laboratory (INEEL), has evaluated the -
information provided by the licensee in support of its First Ten-Year Interval inservice Inspection Program Requests for Relief Nos. B-3 through B-6, C-2, and C-3 for CPSES, Unit 2.
Based on the results of the review, the staff adopts the contractor's conclusions and recommendations presented in the Technical Letter Report (TLR) attached.
The information provided by the licensee in support of the requests for relief from Code requirements has been evaluated and the basis for disposition is documented below.
Request for Relief No. B-3:. ASME Code, section XI, Examination Category B-J, item B9.31 requires 100 percent surface and volumetric examination of branch connection welds NPS 4
- and larger, each inspection interval as defined by Figures IWB-2500-9, -10, and -11.
Pursuant to 10 CFR 50.55a(g)(5)(iii), the licensee requested relief from the Code-required 100 percent volumetric examination for branch connection-to-pipe Weld TCX 1-4104-1.
The Code requires that the subject branch connection weld receive 100 percent volumetric and surface examination. The staff has reviewed the information and figures provided by the i licensee that describe the limitations and depict the pipe-to-branch connection joint configuration. The staff determined that due to the surface geometry and the limited access to j one side of the weld, the Code-required volumetric examination is impractical. For the licensee to obtain complete volumetric coverage, design modifications would be required, and cause a burden on the licensee.
The licensee proposed to use the volumetric and surface examinations performed as an !
attemative to the Code-required examination. All of the weld was covered in at least one beam path direction and 77 percent of the required examination volume was scanned in two beam path directions. Full circumferential scan coverage was obtained. The subject weld also received 100 percent surface examination. Based on the examination coverage obtained, the 100 percent surface examination performed, and on other examinations of similar components, the staff concluded that a pattern of degradation, if present, would be detected. As a result, the licensee's proposed alternative provides reasonable assurance of structuralintegrity of the subject welds. Therefore, relief is granted, pursuant to 10 CFR 50.55a(g)(6)(l) for the current
' interval.
Request for Relief No. B-4: ASME Code,Section XI, Examination Categories B-B and B D, items B2.11 and B3.110 require 100 percent volumetric examination of the pressurizer circumferential shell-to-head welds, as defined by Figure IWB-2500-1, and of pressurizer nozzle-to-vessel welds, as ddined by Figure IWB-2500-7, each inspection interval.
Pursuant to 10 CFR 50.55a(g)(5)(iii), the licensee requested relief from the Code-required 100
. percent volumetric examination of pressurizer lower head-to-shell Weld TCX-1-2100-1 and pressurizer surge nozzle to-vessel Weld TCX-1-2100-11.
The Code requires 100 percent volumetric examination of the pressurizer lower head-to-shell and surge nozzle-to-vessel welds each interval. The staff has reviewed the information and figures provided by the licensee that describe the limitations associated with examination of the subject welds. The staff determined due to the surface geometry and interferences from
4 instrument lines, welded pads, the support skirt, and, for the pressurizer surge nozzle, the heater penetrations, the Code required examination requirements are impractical for the ;
subject welds. To obtain complete volumetric coverage, design modifications would be -
required,' causing a burden on the licensee.
~ The licensee proposed to use the volumetric examinations performed as an alternative to the Code required examinations. Virtually all (97 percent) of the weld was covered in at least one beam path direction and 84 percent of the required examination volume was scanned in two beam path directions on the shell-to-head weld. Approximately 52 percent of the surge nozzle-to-vessel weld volume received the full Code-required examination; approximately 65 percent of the required volume was examined in at least one beam path direction with two different beam angles and approximately 80 percent of the required volume was examined in at least one beam path direction with one bearn angle. Both welds received full circumferential scan coverage. Based on the examination coverage obtained on the subject welds and examinations performed on similar components, it can be concluded that a pattern of degradation, if present, would have been detected. As a result, the license's proposed attemative provides reasonable assurance of structuralintegrity of the subject welds.
Therefore, the licensee's request for relief is granted, pursuant to 10 CFR 50.55a(g)(6)(i) for the current interval.
Request for Rollef No. B-5: ASME Code,Section XI, Examination Category B-8, item B2.40 requires 100 percent volumetric examination of the steam generator tubesheet-to-head weld, as defined by Figure IWB-2500-6, each inspection interval.
Pursuant to 10 CFR 50.55a(g)(5)(iii), the licensee requested relief from the Code-required 100 '
_ percent volumetric examination of steam generator tubesheet-to-channel head Weld TCX-1-3100-2-1.
The Code requires that the subject tubesheet-to-head weld receive 100 percent volumetric examination. The staff reviewed the information and figures provided by the licensee that describe the limitations associated with the tubesheet flange configuration and the welded insulation support pads. The staff determined that due to the limited access to the weld, the Code required volumetric examination is impractical. To obtain complete volumetric coverage, design modifications would be required, causing a burden on the licensee.
The licensee proposed to use the volumetric examinations performed as an altemative to the Code-required examination. Sixty-nine percent of the Code-required volume was examined.
Based on the examination coverage obtained, it can be concluded that any significant pattems of degradation that may occur should have been detected. The staff has determined that as a result, the licensee's proposed alternative provides reasonable assurance of structural integrity of the subject welds. Therefore, the licensee's request for relief is granted, pursuant to 10 CFR 50.55a(g)(6)(i).
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,4, Request for Rollef No. B-6: ASME Code,Section XI Examination Category B-J, item B9.11 requires 100 percent surface and volumetric examinations of selected circumferential pipe welds, NPS 4 and greater, as defined by Figure IWB-2500-8.
Pursuant to 10 CFR 50.55a(g)(5)(iii), the licensee requested relief from the Code-required 100 percent volumetric examination of pipe-to-valve Weld TCX-1-4201-7.
The Code requires 100 percent surface and volumetric examination of Class 1 circumferential pressure-retaining pipe welds greater than or equal to 4-inch NPS. However, component geometry and pipe hanger interferences restrict coverage and preclude 100 percent volumetric
-O examination of valve-to-pipe Weld TCX-1-4201-7. The volumetric examination is, therefore, impractical. To meet the Code requirements, the weld joint or pipe hanger would have to be redes!gned and modified. Imposition of this requirement would result in a burden on the licensee.
The licensee examined approximately 79 percent of the required weld volume. The combination of the volumetric examination to the extent practical, complete surface examination, and VT-2 visual examination, as required by the Code, and examination of other Examination Category B J welds assures that existing patterns of degradation would have been detected. As a result, reasonable assurance of the structuralintegrity of the subject weld has been provided. Therefore, the licensee's request for relief is granted pursuant to 10 CFR 55.55a(g)(6)(i) for the current interval.
. Request for Rollef No. C-2: ASME Code,Section XI, Examination Category C-A, item C1.30 requires 100 percent volumetric examination, as defined by Figure IWB-2500-2, for tubesheet-to-shell welds each inspection interval.
Pursuant to 10 CFR 50.55a(g)(5)(iii), the licensee requested relief from the Code required 100 percerit volumetric examination of regenerative heat exchanger tubesheet-to-shell Welds TCX-2-1150-5 and -6.
The Code requires 100 percent volumetric examination of the subject regenerative heat exchanger tubesheet-to-shell welds However, examination of these welds is restricted by the heat exchanger shell side inlet and outlet nozzles. The geometric conditions limit the volumetric examination of the tubesheet to-shell weld to an estimated 90 percent of the required volume.
The volumetric examination is, therefore, impractical to perform to the extent required by the Code. To meet the Code requirements, the regenerative heat exchanger would have to be redesigned and modified. Imposition of this requirement would result in a burden on the licensee.
The licensee examined a significant portion (90 percent) of the required weld volume. The combination of the volumetric examination to the extent practical and the Code-required VT-2 visual examination assures that existing pattems of degradation would have been detected. As
~ a result, reasonable assurance of the structuralintegrity of the subject welds has been provided. Therefore, the licensee's request for relief is granted pursuant to 10 CFR 55.55a(g)(6)(i) for the current interval.
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. Request for Relief No. C-3: Examination Category C-C, item C3.20 requires 100 percent surface examination of integrally welded attachments, as defined by Figure IWC-2500-5,~of those components required to be examined under Examination Categories C-F and C-G.
Pursuant to 10 CFR 50.55a(g)(5)(iii), the licensee requested relief from the Code-required 100 percent surface examination of 8 of the 16 welded lug attachments on piping component Support TCX-2-2301-H1. .
The licensee requested relief from the Code-required 100 percent sudace examination of the subject integrally welded attachments. The INEEL staff has reviewed the information and figures provided by the licensee that describe the limitations associated with the welded attachments on component support TCX-2-2301-H1. Because of the limited access to the welded lug attachments, the Code required surface examination is impractical. To obtain complete surface examination coverage, design modifications would be required, causing a significant burden on the licensee.
l The licensee has performed the surface examinations on 8 of the 16 welded lug attachments.
Based on the coverage obtained, it is reasonable to conclude that degradation, if present, would have been detected. The staff determined that the licensee's alternative provides j reasonable assurance of structuralintegrity of the subject welds. Therefore, the licensee's j request for relief is granted pursuant to 10 CFR 50.55a(g)(6)(l).
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3.0 CONCLUSION
For Requests for Relief Nos. B-3, B-4, B-5, B-6, C-2, and C-3, the staff concluded that the examinations are impractical to pedorm to the extent required by the Code. In each case, the examinations performed provide reasonable assurance of the continued inservice structural integrity of the subject components. Therefore, the licensee's requests for relief are granted, pursuant to 10 CFR 50.55a(g)(6)(i) for the current interval. The relief granted is authorized by law and will not endanger life or property, the common defense and security, and is otherwise in the public interest giving due consideration to the burden upon the licensee if the requirements were imposed on the facility.
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Attachment:
Technical Letter Report ,
Principal Contributor: T. McLellan Date: February 3, 1999 l'
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TECHNICAL LETTER REPORT ON FIRST 10-YEAR INTERVAL INSERVICE INSPECTION REQUESTS FOR RELIEF NOS. B-3 THROUGH B-6. C-2. AND C-3 EQB TEXAS UTILITIES ELECTRIC CO.
COMANCHE PEAK STEAM ELECTRIC STATION. UNIT 2 DOCKET NUMBER: 50-446
Electric Co., submitted Requests for Relief Nos. B-3 through B-6, C-2, and C-3 seeking relief from the requirements of the ASME Code,Section XI, for the Comanche Peak 1
Steam Electric Station (CPSES), Unit 2 first 10-year inservice inspection (ISI) interval. l The Idaho National Engineering and Environmental Laboratory (INEEL) staff's evaluation of the subject requests for relief are in the following section.
i
- 2. EVALUATION ,
1 The information provided by TU Electric in support of the requests for relief from Code requirements has been evaluated and the bases for disposition are documented below.
The Code of record for the CPSES, Unit 2, first 10-year ISI interval, which began August 3,1993,is the 1986 Edition of Section XI of the ASME Boiler and Pressure Vessel Code.
A. Reauest for Relief No. B-3. Examination Cateoorv B-J. Item B9.31. Branch Connection-to-Pioe Weld Code Recuirement: Examination Category B-J, item B9.31 requires 100% surface and volumetric examination of branch connection welds NPS 4 and larger each inspection interval as defined by Figures IWB-2500-9, -10, and -11.
Licensee's Code Relief Reauest: In accordance with 10 CFR 50.55a(g)(5)(iii), the licensee requested relief from the Code-required 100% volumetric examin ion for branch connection-to-pipe Weld TCX-1-4104-1.
ATTACHMENT
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2 Licensee's Basis for Reauestina Relief (as stated):
. The specific examination area geometry of this pipe-to-branch connection weld precludes the complete ultrasonic examination of the volume required by Fig. lWB-2500-10. Approximately 23% of the examination volume did not receive the full
' code required coverage.
"A best effurt examination was performed. Full circumferential scan coverage was obtained. Axial scan coverage was achieved in one beam path direction with at least one beam angle for 100% of the examination volume.
"There were no recordabie indications identified by the best effort volumetric 4
examination or by the required surface examination performed."
Licensee's Proposed Alternative Examination: The licensee proposed to use the volumetric examination performed, along with the Code-required surface examination, as an alternative to the Code-required 100% volumetric examination of branch connection-
- to-pipe Weld TCX-1-4104-1.
I Evaluation: The Code requires that the subject branch connection weld receive 100%
volumetric and surface examination. The INEEL staff has reviewed the information and figures provided by the licensee that describe the limitations and depict the pipe to-branch connection joint configuration. Due to the surface geometry and the limited access to one side of the weld, the Code required volumetric examination is impractical.
To obtain complete volumetric coverage, design modifications would be required, causing
- a significant burden on the licensee.
. The licensee proposed to use the volumetric and surface examinations performed as an alternative to the Code-required examination. All of the weld was covered in at least one beam path direction and 77% of the required examination volume was scanned in two beam path directions. Full circumferential scan coverage was obtained. The subject weld also received 100% surf ace examination. Based on the examination coverage
~ obtained, the 100% surface examination performed, and on other examinations of similar
- components, it can be concluded that a pattem of degradation, if present, would have been detected. As a result, reasonable assurance of structuralintegrity has been provided. Therefore, it is recommended that relief be granted, pursuant to 10 CFR 50.55a(g)(6)(i).
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B. Reauest for Relief No. B-4. Examination Cateaories B-B and B-D. Items B2.11 and B3.110. Pressurizer Shell-to-Head and Surae Nozzle-to-Vessel Welds Code Reauirement: Examination Categoriea B-B and B-D, items B2.11 and B3.110 require 100% volumetric examination of the pressurizer circumferential shell-to-head .
welds, as defined by Figure IWB 2500-1, and of pressurizer nozzle-to-vessel welds, as l defined by Figure IWB-2500-7, each inspection interval.
c Licensee's Code Relief Reauest: In accordance with 10 CFR 50.55a(g)(5)(iii), the licensee requested relief from the Code-required 100% volumetric examination of ,
1 pressurizer lower head-to-shell Weld TCX-1-2100-1 and pressurizer surge nozzle-to-vessel Weld TCX-1-2100-11.
Licensee's Basis for Reauestina Relief (as stated):
"The specific examination area geometry of the lower head to shell weld and interferences from instrumentation lines, welded pads and the support skirt - j preclude the completo ultrasonic examination of the volume required by Fig. lWB-2500-1 for weld TCX-1-2100-1. Approximately 16% of the volume did not receive the full code required coverage. Best effort examinations were performed. Full circumferential scan coverage was obtained. Axial scan coverage was achieved for approximately 97% of the required volume in at least one beam path direction with one angle.
"The specific examination area geometry of the surge nozzle to vessel weld and interferences from pressurizer lower head heater penetrations preclude the complete ultrasonic examination of the volume required by Fig. lWB-2500-7 for TCX-1 2100-11. Approximately 48% of the volume did not receive the full code required coverage. Best effort examinations were performed. Full circumferential scan coverage was obtained. Axial scan coverage was achieved for approximately i 65% of the required volume in at least one beam path direction with two different beam angles and for approximately 80% of the required volume in at least one beam path direction with one beam angle.
"There were no recordable indications identified by the best effort examinations performed."
Licensee's Proposed Altemative Examination: The licensee proposed to use the volumetric examinations performed as an alternative to the Code-required 100%
vokJmetric examination of pressurizer lower head-to-shell Weld TCX-1-21001 and
= presAurizer surge nozzle-to-vessel Weld TCX-1-2100-11.
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Evaluation: The Code requires 100% volumetric examination of the pressurizer lower head-to-shell and surge nozzle-to-vessel welds each interval. The INEEL staff has -
reviewed the information and figures provided by the licensee that describe the limitations associated with examination of the subject welds. Due to the surface geometry and interferences from instrument lines, welded pads, the support skirt, and, for the a
pressurizer surge nozzle, the heater penetrations, the Code-required examination requirements are impractical for the subject welds. To obtain complete volumetric ,
coverage, design modifications would be required, causing a significant burden on the ,
licensee.
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The licensee proposed to use the volumetric examinations performed as an altemative to
, the Code-required examinations. Virtually all (97%) of the weld was covered in at least
. one beam path direction and 84% of the required examination volume was scanned in two beam path directions on the shell-to-head weld. Approximately 52% of the surge t
nozzle-to-vessel weld volume received the full Code-required examination; approximately
~ 65% of the required volume was examined in at least one beam path direction with two f . different beam angles and approximately 80% of the required volume was examined in at least one beam path direction with one beam angle. Both welds received full circumferential scan coverage. Based on tha examination coverage obtained on the subject welds and examinations performed on similar components, it can be concluded that a pattem of degradation,if present, would have been detected. As a result, reasonable assurance of structuralintegrity has been provided. Therefore, it is recommended that relief be granted, pursuant to 10 CFR 50.55a(g)(6)(i).
C.~ Reouest for Relief No. B-5. Examination Cateoorv B-B. Item B2.40. Steam Generator Tubesheet-to-Channel Head Weld -
Code Reauirement: Examination Category B-B, item B2.40 requires 100% volumetric examination of the steam generator tubesheet-to-head weld, as defined by Figure IWB-
' 2500-6, each inspection interval.
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5 Licensee's Code Relief Reauest: In accordance with 10 CFR 50.55a(g)(5)(iii), the licensee requested relief from the Code-required 100% volumetric examination of steam generator tubesheet-to-channel head Weld TCX-1-3100 2-1.
d Licensee's Basis for Reauestina Relief (as stated):
" Interferences from the steam generator tubesheet flange (or support collar) configuration and from welded insulation support pads preclude the complete ultrasonic examination of the volume required by Fig. lWB-2500-6. Approximately 31% of the examination volume of weld TCX-1-3100-2-1 did not receive the full code required coverage. . .
- There were no recordable indications identified by the volumetric examination performed on the accessible portions of the weld."
Licensee's Proposed Alternative Examination: The licensee proposed to use the volumetric examinations performed as an alternative to the Code-required 100%
volumotric examination of steam generator tubesheet-to-channel head Weld TCX-1-3100-2-1.
Evaluation: The Code requires that the subject tubesheet-to-head weld receive 100%
volumetric examination. The INEEL staff reviewed the information and figures provided by the licensee that describe the limitations associated with the tubesheet flange configuration and the welded insulation support pads. Due to the limited access to the weld, the Code-required volumetric examination is impractical. To obtain complete volumetric coverage, design modifications would be required, causing a significant burden on the licensee.
- The licensee proposed to use the volumetric examinations performed as an alternative to
, the Code-required examination. Sixty-nine percent of the Code-required volume was examined. Based on the examination coverage obtained, it can be concluded that any significant pattems of degradation that may occur should have been detected. As a result. reasonable assurance of structural integrity has been provided. Therefore, it is recommended that relief be granted, pursuant to 10 CFR 50.55a(g)(6)(i).
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= D. Reauest for Relief No. B-6. Examination Cateaorv B-J. Item B9.11. Pressure-Retaining Circumferential Pioe Welds l
Code Reauirement: Examination Category B-J, item B9.11 requires 100% surface and l volumetric examinations of selected circumferential pipe welds, NPS 4 and greater, as defined by Figure IWB-2500-8.
Licensee's Code Relief Reauest: In accordance with 10 CFR 50.55a(g)(5)(iii), the licensee requested' relief from the Code-required 100% volumetric examination of pipe-to-
' valve Weld TCX-1-4201-7.
Licensee's Basis for Reauestina Relief (as stated):
"The specific pipe to valve examination geometry and interferences from reactor building structural steel members preclude the complete ultrasonic examination of the volume required by Fig.'IWB-2500-8. Approximately 21% of the volume did not receive the full code required coverage. . .
"There were no recordable indications identified by the volumetric examination performed on the accessible portion of the weld or by the complete surface L examination performed."
Licensee's Prooosed Alternative Examination: The licensee proposed to use the volumetric examinations performed as an alternative to the Code-required 100%
L volumetric examination of pipe-to-valve Weld TCX-1-4201-7. In addition, the licensee l-stated:
". . . welds at this same location in loops 1,3 and 4 are included in the ISI Plan and are scheduled for examination during this interval."
l Evaluation: The Code requires 100% surface and volumetric examination of Class 1 circumferential pressure-retalning pipe welds greater than or equal to 4-inch NPS.
However, component geometry and pipe hanger interferences restrict coverage and L-preclude 100% vc!umetric examination of valve-to-pipe Weld TCX-1-4201-7. The volumetric examination is, therefore, impractical. To meet the Code requirements, the weld joint or pipe hanger would have to be redesigned and modified. Imposition of this
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requirement would result in a burden on the licensee.
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7 The licensee examined approximately 79% of the required weld volume. The combination of the volumetric examination to the extent practical, complete surface examination, and VT-2 visual examination, as required by the Code, and examination of other Examination Category B-J welds assures that existing patterns of degradation would have been detected. As a result, reasonable assurance of the structuralintegrity of the subject weld has been provided. Therefore, it is recommended that relief be granted pursuant to 10 CFR 55.55a(g)(6)(i).
A E. ' Reauest for Relief No. C-2.' Examination Cateaorv C-A. Item C1.30. Reaenerative Heat Exchanaer Tubesheet to-Shell Welds
.\l Code Reauirement: Examination Category.C-A, Item C1.30 requires 100% volumetric examination, as defined by Figure IWB-2500-2, for tubesheet-to-shell welds each inspection interval. !
l Licensee's Code Relief Reauest: In accordance with 10 CFR 50.55a(g)(5)(iii), the I licensee requested relief from the Code-required 100% volumetric examination of regenerative heat exchanger tubesheet-to-shell Welds TCX-2-1150-5 and -6.
Licensee's Basis for Reauestina Relief (as stated):
" Interferences from the heat exchanger inlet and outlet nozzles preclude the complete ultrasonic examination of the volume required by Fig. IWC-2500-2.
Approximately 10% of the weld length did not receive the full code required examination. . . .
"There were no recordable indications identified by the volumetric examinations l performed on the accessible portion of the weld length." j
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, Licensee's Prooosed Alternative Examination: The licensee proposed to use the I volumetric examinations performed as an attemative to the Code-required 100% ;
, 1 volumetric examination of regenerative heat exchanger Welds TCX-2-1150-5 and -6.
Evaluation: .The Code requires 100% volumetric examination of the subject regenerative heat exchanger tubesheet to-shell welds. However, examination of these welds is restricted by the heat exchanger shell-side inlet and outlet nozzles. The geometric conditions limit the volumetric examination of the tubesheet-to-shell weld to an estimated ;
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. 8 90% of the required volume. The volumetric examination is, therefore, impractical to perform to the extent required by the Code. To meet the Code requirements, the regenerative heat exchanger would have to be redesigned and modified. Imposition of this requirement would result in a burden on the licensee.
The licensee examined a significant portion (90%) of the required weld volume. The combination of the volumetric examination to the extent practical and the Code-required VT-2 visual examination assures that existing pattems of degradation would have been detected. As a result, reasonable assurance of the structuralintegrity of the subject welds has been provided. Therefore, it is recommended that relief be granted pursuant to 10 CFR 55.55a(g)(6)(1).
1 F. Reauest for Relief No. C-3. Examination Cateaorv C-C. Item C3.20. Class 2 Intearally Welded Attachments to Pioina )
l Code Reautrement: Examination Category C-C, Item C3.20 requires 100% surface e examination of integrally welded attachments, as defined by Figure IWC-2500-5, of those
- components required to be examined under Examination Categories C-F and C-G.
Licensee's Code Relief'Reauest: In accordance with 10 CFR 50.55a(g)(5)(iii), the licensee requested relief from the Code-required 100% surface examination of 8 of the 16 welded lug attachments on piping component Support TCX 2-2301-H1.
Licensee's Basis for Reauestina Relief (as stated): j
-"The specific component support configuration precludes the complete surface examination of the area required by Fig. lWC-2500-5. 8 of the 16 welded lug attachments are inaccessible due to 2% inch thick plates that surround the pipe clamp and are welded to an anchor bolted wall plate. . . .
- "There were no recordable indications identified by the surface examination performed on the accessible lug attachment welds."
Licensee's Prooosed Alternative Examination: The licensee is proposing to use the !
surface examinations performed as an alternative to the Code-required 100% surface examination of piping integrally welded attachments to component Support TCX-2 2301-H1.
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Evaluation: The licensee requested relief from the Code-required 100% surface examination of the subject integrally welded attachments. The INEEL staff has reviewed ,
the information and figures provided by the licensee that describe the limitations associated with the welded attachments on component support TCX-2-2301-H1.
1 Because of the limited access to the welded lug attachments, the Code-required surface examination is impractical. To obtain complete surface examination coverage, design modifications would be required, causing a significant burden on the licensee.
The licensee has performed the surface examinations on 8 of the 16 welded lug attachments. Based on the coverage obtained,it is reasonable to conclude that degradation, if present, would have been detected. Consequently, reasonable assurance of structuralintegrity has been provided. Therefore,it is recommended that relief be granted pursuant to 10 CFR 50.55a(g)(6)(l).
' 3.
. CONCLUSION The INEEL staff evaluated the licensee's submittal and concluded that certain inservice examinations cannot be performed to the extent required by the Code at the CPSES, Unit
- 2. For Requests for Relief Nos. B-3, B-4, B-5, B-6, C-2, and C-3, the examinations are impractictil to perform to the extent required by the Code, in each case, the examinations performed provide reasonable assurance of the continued inservice structural integrity of the subject components and it is recommended that relief be granted, for each request, pursuant to 10 CFR 50.55a(g)(6)(i).
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