ML20196L019
| ML20196L019 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 07/08/1999 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20196L015 | List: |
| References | |
| NUDOCS 9907120265 | |
| Download: ML20196L019 (14) | |
Text
.
neep .
p '4 UNITED STATES s* B NUCLEAR REGULATORY COMMISSION WASHINGTON. D.C. 30865-0001
- %...../
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION FIRST 10-YEAR INTERVAL INSERVICE INSPECTION PLAN REQUESTS FOR RELIEF NOS. B-6 (REV. 2L B-7 (REV. 2L B-12. B-13. B-14. AND C-9 TEXAS UTILITIES ELECTRIC COMPANY COMANCHE PEAK STEAM ELECTRIC STATION. UNIT 1 s
DOCKET NO. 50-445
1.0 INTRODUCTION
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 Code and applicable addenda as required by Title 10 of the Code of Federal Reaulations. Section 50.55a(g) (10 CFR 50.55a(g)), except where specific written relief has been granted by the Commission pursuant to 10 CFR 50.55a(6)(g)(i). Section 50.55a(a)(3) states that alternatives to the requirements of paragraph (g) may be used, when authodzed by the NRC, 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. l 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 j preservice 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 j
- regulations require that inservice examination of components and system pressure tests i conducted during the first 10-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) 12 months prior to the start of the 120-month interval, subject to the limitations and modifications listed therein. For Comanche Peak Steam Electric Station, Unit 1, the applicable edition of Section XI of the ASME Code for the first 10-year inservice l inspection (IS) interval is the 1986 Edition.
2.0 EVALUATION ,
The Idaho National Engineering and Environmental Laboratory's evaluation of the subject Requests for Relief Nos. B-6 (Rev. 2), B-7 (Rev. 2), B-12, B-13, B-14, and C-9 is in the attachment to this Safety Evaluation. Based on the results of the review, the staff adopts the 9907120265 990708 Enclosure PDR ADOCK 05000445 P PDR
contractor's conclusions and recommendations presented in the Technical Letter Report attached to this Safety Evaluation.
- The information provided by Texas Utilities Electric Company (the licensee) in support of the requests for relief from Code requirements has been evaluated and the basis for disposition is documented below.
Reauest for Relief No. B-6. Revision 2:
ASME Code,Section XI, Examination Category B-A, item B1.21 requires 100 percent volumetric examination of the accessible portion of all circumferential head welds, as defined by Figure IWB-2500-3. Item B1.40 requires 100 percent volumetric and surface examination of the reactor pressure vessel (RPV) head-to-flange welds as defined by Figure IWB-2500-5.
Pursuant to 10 CFR 50.55a(g)(5)(iii), the licensee requested relief from the Code-required volumetric examination of 100 percent of the following welds:
TBX-1-1300-1 Closure Head to-Flange Weld TBX-1-1300-2 Ring-to-Disc Weld The NRC staff determined that complete examination coverage is limited by physical interferences from the reactor head flange, shroud, and lifting lugs. Tnese conditions make 100 percent volumetric examination impractical for these weids. To gain access for i examination, the RPV head would require design modifications. Imposition of this requirement l would be a significant burden on the licensee. 1 The licensee has examined a significant portion of these welds; examination volumes achieved range from 83 to 85 percent of each weld. In addition,100 percent of the required surface examination of the subject B1.40 weld was performed. Therefore, based on the volumetric and surface coverage obtained, the staff concludes that the examinations performed provide reasonable assurance of structure! integrity of the subject welds. Therefore, relief is granted i
. pursuant to 10 CFR 50.55a(g)(6)(i). ;
i Reauest for Relief No. B-7. Revision 2:
ASME Code,Section XI, Examination Category B-B, item B2.40 requires 100 percent <
volumetric examination of tubesheet-to-chanel head welds on vesssis other than reactor vessels, as defined in Figure IWB 2500-6.
Pursuant to 10 CFR 50.55a(g)(5)(iii), the licensee requested relief from the Code-required 100 percent volumetric examinations of steam generator tubesheet-to-chanel head Welds TBX-1-3100-1-1, TBX-1-3100-2-1, TBX-1-3100-3 1, and TBX-1-3100-4-1.
Relief was granted for the original relief request and Revision 1 in NRC staff Safety Evaluations dated February 14,1995, and December 28,1995, respectively. The original version of this request for relief documents the specific limitations encountered and the examination coverage achieved for Weld TBX-13100-1-1; Revision 1 documents the specific limitations encountered and the examination coverages achieved for Welds TBX-1-3100-1-1 and TBX-1-3100-2-1.
- r. , ,
Revision 2 documents the specific limitations encountered and the examination coverages achieved for Welds TBX-1-3100-1-1, TBX-1-3100-2-1, TBX-1-3100-3-1, and TBX-1-3100-4-1.
The staff determined that complete examination coverage is limited by physical interferences from the steam generator tubesheet flange configuration, welded insulation support pads, and welded component name tags. These conditions make 100 percent volumetric examination impractical for these welds. To gain access for examination, the steam generator would require design modifications, imposition of this requirement would impose a significant burden on the licensee.
The licensee has examined a significant portion of these welds; examination volumes achieved range from 63 to 69 percent of each weld. Therefore, based on the volumetric coverage obtained, the staff concludes that the examinations performed provide reasonable assurance of structural integrity of the subject welds. Therefore, relief is granted pursuant to 10 CFR 50.55a(g)(6)(i).
Reauest for Relief No. B-12:
ASME Code,Section XI, Examination Category B B, item B2.11 requires 100 percent volumetric examination of Pressurizer Circumferential Shell-to-Head Welds defined in Figure IWB-2500-1.
Pursuant to 10 CFR 50.55a(g)(5)(iii), the licensee requested relief from the Code-required
- 100 percent volumetric examinations of the Pressurizer Lower Head to Shell Weld TBX-1 2100-1.
The staff determined that complete examination coverage is limited by the geometry of the lower head to shell weld and physical interferences from instrumentation lines, welded pads, and the support skirt. These conditions make the 100 percent volumetric examination impractical for the subject weld. To gain access for examination, the pressurizer would require design modifications. Imposition of this requirement would impose a significant burden on the licensee.
The licensee has examined a significant portion of the weld (84 percent). Therefore, based on
~ the volumetric coverage obtained, the staff concludes that the examinations performed provide reasonable assurance of structural integrity of the subject welds. Therefore, relief is granted pursuant to 10 CFR 50.55a(g)(6)(i).
Reouest for Relief No. B-13:
ASME Code,Section XI, Examination Category B-J, item B9.11 requires 100 percent volumetric and surface examination, as defined by Figure IWB-2500-8, for Class 1 circumferential welds in piping 4-inch nominal pipe size and larger.
Pursuant to 10 CFR 50.55a(g)(5)(iii), the licensee requested relief from the Code-required
- 100 percent volumetric and surface examinations of Welds Nos. TBX-1-4102-7, TBX-1-4301-7, and TBX-1-4402-7. The staff determined that component configuration and interference from other components limit access and preclude complete volumetric examination of these welds. I in two cases, surface examination is also limited. To meet the Code examination requirements, l
l
- - design modifications.would be necessary. Therefore, the Code volumetric and surface examination requirements, as applicable, are impractical for these welds. Imposition of this requirement would create a significant burden on the licensee.
The licensee has examined 39 to 45 percent of the required volume, and 60 to 100 percent of the surface examination coverage on the three welds. In addition, these welds are part of a larger sample of B-J welds to be examined. The staff concludes that the examinations performed provide reasonable assurance of structuralintegrity of the subject welds. Therefore,
. relief is granted pursuant to 10 CFR 50.55a(g)(6)(i).
Reauest for Relief No. B-14:
ASME Code,Section XI, Examination Category B-J, item B9.31 requires 100 percent volumetric and surface examination, as defined by Figures IWB-2500-9,10, and 11, for Class 1 branch pipe connection welds in piping 4-inch nominal pipe size and larger.
Pursuant to 10 CFR 50.55a(g)(5)(iii), the licensee requested relief from the Code-required 100 percent volumetric examination of Branch Pipe Connection Weld TBX-1-4404-1.
The staff determined that component geometry (surface contour of the examination surface) limits access and precludes complete volumetric examination of the subject weld and the Code requirements are impractical. To meet the Code examination requirements, design modifications would be necessary. Imposition of this requirement would create a significant burden on the licensee.
The licensee has examined a significant portion (74 percent) of the required volume of the weld, and examined 100 percent of the surface. In addition, this weld is part of a larger sample of B-J branch connection welds to be examined. The staff concluded that the examinations performed provide reasonable assurance of structuralintegrity of the subject welds. Therefore,
- relief is granted pursuant to 10 CFR 50.55a(g)(6)(i).
Reauest for Relief No. C-9:
ASME Code,Section XI, Examination Category C-A, item Numbers C1.10 and C1.20 require 100 percent volumetric examination, as defined by Figure IWC-2500-1, for Class 2 shell and head circumferential pressure vessel welds.
Pursuant to 10 CFR 50.55a(g)(5)(lii), the licensee requested relief from the Code-required 100 percent volumetric examination of the following welds:
TBX-21110-1 Excess Letdown Heat Exchanger Head to Flange Weld TBX-2-1180-2-2 Containment Spray Heat Exchanger Shell to Flange Weld The staff determined that the inlet and ot,tlet nozzles, instrumentation nozzles, and component geometry (flange tape,c) limit access and preclude complete volumetric examination of the subject welds and the Code volumetric examination requirements are impractical for the subject welds. To meet the Code ecamination requirements, design modifications would be necessary and would be a significant buden on the licensee.
I
- The licensee has examined 50 percent of the required volume of Weld TBX-2-1110-1 and 73 percent of the volume of Weld TBX-2-1180-2-2. The staff concluded that the volumetric coverage obtained, provides reasonable assurance of structural integrity of the subject welds.
Therefore, relief is granted pursuant to 10 CFR 50.55a(g)(6)(i).
3.0 CONCLUSION
For Requests for Relief B-6 (Rev. 2), B-7 (Rev. 2), B-12, B-13, B-14, and C-9, the. staff concludes that the Code requirements are impractical and that the examinations performed provide reasonable assurance of structuralintegrity subject welds. Therefore, Requests for Relief B-6 (Rev. 2), B-7 (Rev. 2), B-12, B-13, B-14, and C-9 are granted pursuant to 10 CFR 50.55a(g)(6)(i). 1
Attachment:
Technical Letter Report Principal Contributor: T. McLellan Date: July 8,1999 sm ,=
TECHNICAL LETTER REPORT l ON FIRST 10-YEAR INTERVAL INSERVICE INSPECTION REQUESTS FOR RELIEF B-6 R.2. B-7 R.2. B-12. B-13. B-14. AND C-9 EQB l TU ELECTRIC COMANCHE PEAK STEAM ELECTRIC STATION - UNIT 1 DOCKET NUMBER: 50-445
- 1. INTRODUCTION
- By letter dated July 22,1998, the licensee, TU Electric, submitted Requests for Relief B-6 l (Rev. 2), B-7 (Rev. 2), B-12, B-13, B-14, and C-9 seeking relief from the requirements of the ASME Code,Section XI, for the Comanche Peak Steam Electric Station (CPSES)-
Unit 1, first 10-year inservice inspection (ISI) interval. The Idaho National Engineering and Environmental Laboratory (INEEL) staff's evaluation of the subject requests for relief is in the following section.
- 2. EVALUATION' i
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 1, first 10-year ISI interval, which began August 13,1990, is the 1986 Edition of Section XI of the ASME Boiler and Pressure Vessel Code.
A. Reauest for Relief No. B-6. Revision 2. Examination Cateaorv B-A. Items 81.21 and B1.40. Pressure-Retainina Welds in the Reactor Vessel (RPV)
Code Reauirement: Examination Category B-A, Item B1.21 requires 100% volumetric examination of the accessible portion of all circumferential head welds, as defined by Figure IWB-2500-3. Item B1.40 requires 100% volumetric and surface examination of RPV head-to-flange welds as defined by Figure IWB-2500-5.
Licensee's Code Relief Reauest: In accordance with 10 CFR 50.55a(g)(5)(iii), the licensee requested relief from the Code-required volumetric examination of 100% of the following welds.
TBX-1-1300-1 Closure Head to Flange Weld TBX-1-1300-2 Ring to Disc Weld Licensee's Basis for Reauestina Relief (as stated):
" Note - The CPSES ISI Plan req'u lres that 1/3 of each of these welds be examined each inspection period. A relief request revision is processed to document the specific limitations encountered during each examination.
Enclosures, tables, figures, and attachments furnished with the licensee's submittal are not included in this report.
Attachnent l
I l
l "Interierences from the reactor head flange, shroud and lifting lugs preclude the complete ultrasonic examination of the volume required by Fig.'s IWB 2500-3 and IWB-2500-5 as applicable.
"Approximately 13% of the examination volume of weld TBX-1-1300-1 and 17% of the examination volume of weld TBX-1-1300-2 did not receive the full code l required coverage during the first period examinations.
"Approximately 15% of the examination volume of weld TBX-1-1300-1 and 17% of the examination volume of weld TBX-1-1300-2 did not receive the full code required coverage during the second period examinations.
"Approximately 15% of the examination volume of weld TBX-1-1300-1 and 17% of the examination volume of weld TBX-1-1300-2 did not receive the full code required coverage during the third period examinations.
"Best effort examinations were performed during each period with the following results. Full circumferential scan coverage was obtained for both welds. Axial scan coverage was achieved in one beam path direction with two different beam angles for approximately 99% of the examination volume of TBX-1-1300-1 and for approximately 97% of the examination volume of TBX-1-1300-2.
"See pages 3 through 11 for weld locations and examination area configurations.
"There were no recordable indications identified by the best effort volumetric examinations performed or by the required surface examination performed on TBX-1-1300-1."
Licensee's ProDosed Alternative Examination (as stated):
"None" Evaluation: Examination Category B-A, item B1.21 requires 100% volumetric examination of the accessible portion of all circumferential head welds and item B1.40 requires 100%
volumetric and surface examination of RPV head-to-flange welds. The licensee provided Limitation to Examination sheets that give the layouts and examination coverages of the subject welds; these are summarized below. ,
Volumetric Coverage Weld First Period Second Period Third Period TBX 1 1300-1 Head-to-Flange 87% 85% 85%
TBX-1 1300-2 Ring-to-Disc 83 % 83 % 83 %
As stated by the licensee and as evidenced by the sketches provided, complete examination coverage is limited by physical interferences from the reactor head flange, j shroud, and lifting lugs. These conditions make 100% volumetric examination impractical 2
r .. -
for these welds. To gain access for examination, the RPV head would require design
- modifications. Imposition of this requirement would create a significant burden on the
{ licensee.
l The licensee has examined a significant portion of these welds; examination volumes l achieved range from 83 to 85% of each weld. In addition,100% of the required surface examination of the subject B1.40 weld was performed. Therefore, based on the volumetric and surface coverage obtained,~ it is concluded that any existing patterns of degradation would have been detected by the examinations that were completed and
- reasonable assurance of structural integrity has been provided.
l Based on the impracticality of meeting the Code examination coverage requirements for l the subject welds, and the reasonable assurance provided by the examinations that were !
completed, it is recommended that relief be granted pursuant to 10 CFR 50.55a(g)(6)(i).
l B. Reauest for Relief No. B-7. Revision 2. Examination Cateaorv B-B. Item B2.40. Class 1 l l Steam Generator Tubesheet-to-Channel Head Weld l l Code Reauirement: Examination Category B-8, item B2.40 requires 100% volumetric
~
- examinstion of tubesheet-to-head welds on vessels other than reactor vessels, as i defined in Figure IWB-2500-6 i l Licensee's Code Relief Recueit
- In accordance with 10 CFR 50.55a(g)(5)(iii), the
! licensee requested relief from the Code-required 100% volumetric examinations of steam l generator tubesheet to-head Welds TBX-1-3100-1-1, TBX-1-3100-2-1, TBX-1-3100-3-1, and TBX-1-3100-4-1.
Licensee's Basis for Reauestina Relief (as stated):
" Note: The CPSES ISI Plan requires different steam generators to be examined during each inspection period. A relief request revision is processed to document the specific limitations encountered during the examination of each of the steam generators.
" interference from the steam generator tube sheet flange configuration, welded insulation support pads and a welded component name tag preclude the complete !
ultrasonic examination of the volume required by Fig. IWB-2500-6.
l "Approximately 31% of the examination volume of weld TBX-1-3100-1-1 did not receive the full code required examination coverage.
"Approximately 37% of the examination volume of weld TBX-1-3100-2-1 did not receive the full code required examination coverage.
"Approximately 31% of the examination volume of weld TBX-1-3100-3-1 did not receive the full code required examination coverage.
"Approximately 31% of the examination volume of weld TBX-1-3100-4-1 did not receive the full code required examination coverage.
3
p .. .
' Licensee's Prooosed Alternative Examination (as stated):
"None - however, manufacturers shop volumetric exam records are available in l permanent plant files" Evaluation: Examination Category B-B, Item B2.40 requires 100% volumetric examination of the tubesheet-to-head welds on vessels other than reactor vessels. Relief was granted for the original relief request and Revision 1 in SERs dated February 14,1995, and December 28,1995, respectively. The original version of this request for relief documents the specific limitations encountered and the examination coverage achieved for Weld TBX-1-3100-1-1; Revision 1 documents the specific limitations encountered and the examination coverages achieved for Welds TBX-1-3100-1-1, and TBX-1-3100 1. Revision 2 documents the specific limitations encountered and the examination coverages achieved for Welds TBX-1-3100-1-1,'TBX-1-3100-2-1, TBX-1-3100-3-1, and TBX-1-3100-4-1.
.The licensee provided Limitation to Examination sheets that give the layouts and examination coverages of the subject welds. As stated by the licensee and as evidenced by the sketches provided, complete examination coverage is limited by physical interferences from the steam generator tube sheet flange configuration, welded insulation support pads, and welded component name tags. These conditions make 100%
volumetric examination impractical for these welds. To gain access for examination, the steam generator would require design modifications. Imposition of this requirement would impose a significant burden on the licensee. l The licensee has examined a significant portion of these welds; examination volumes achieved range from 63 to 69% of each weld. Therefore, based on the volumetric coverage obtained, it is concluded that any existing patterns of degradation would have been detected by the examinations that were completed and reasonable assurance of )
structural integrity has been provided.
Based on the impracticality of meeting the Code examination coverage requirements for the subject welds, and the reasonablo assurance provided by the examinations that were completed, it is recommended that re!iof be granted pursuant to 10 CFR 50.55a(g)(6)(i). ;
i C. Reauest for Relief No. B-12. Examination Cateaorv B-B. Item B2.11. Pressurizer Lower Head to Shell Weld Code Reauirement: Examination Category B-B, item E>2.11 requires 100% volumetric examination of Pressurizer Circumferential Shell-to-Head Welds defined in Figure IWB-2500-1 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 examinations of the Pressurizer Lower Head to Shell Weld TBX-1-2100-1.
i 4
i
l l
l I
Licensee's Basis for Reauestina Relief (as stated): l "The specific examination area geometry of the lower head to shell weld and I interferences from instrumentation lines, welded pads and the support skirt preclude the complete ultrasonic examination of the volume required by Fig. lWB-2500-1 for weld TBX-1-2100-1. Approximately 16% of the volume did not receive the full code required coverage. Best effori c::2minations 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.
"There were no recordable indications identified by the best effort examinations performed. See pages 2 through 4 for weld location and examination area i configuration." l Licensee's Proposed Alternative Examination (as stated):
"None" i
Evaluation: Examination Category B-B, item B2.11 requires 100% volumetric examination of all pressurizer circumferential head welds. The licensee provided Limitation to l Examination sheets that give the layouts and examination coverages of the subject welds. As stated by the licensee and as evidenced by the sketches provided, complete examination coverage is limited by the geometry of the lower head to shell weld and physical interferences from instrumentation lines, welded pads, and the support skirt.
These conditions make the 100% volumetric examination impractical for the subject weld.
To gain access for examination, the pressurizer would require design modifications, imposition of this requirement would impose a significant burden on the licensee. .
The licensee has examined a significant portion of the weld (84%). Therefore, based on the volumetric coverage obtained, it is concluded that any existing patterns of degradation would have been detected by the examinations performed and that reasonable assurance of structuralintegrity has been provided.
Based on the impracticality of meeting the Code examination coverage requirements for the subject weld, and the reasonable assurance provided by the examination that was completed, it is recommended that relief be granted pursuant to 10 CFR 50.55a(g)(6)(i).
D. Reauest for Relief No. B-13. Examination Cateaorv B-J. Item No. 89.11. Circumferential l Welds in Pioina A Code Reouirement: Examination Category B-J, item B9.11 requires 100% volumetric and surface examination, as defined by Figure IWB-2500-8, for Class 1 circumferential i welds in piping 4-inch nominal pipe size and larger.
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 and surface examinations of the following welds.
l 5
i
Volumetric Surface Coverage W old Coverage Obtained Obtained TBX-14102-7 39 % 69%
TBX-1-43017 45% 100 %
TBX-1-4402-7 ' 41% 60 %
Licensee's Basis for Reauestina Relief (as stated):
"The specific pipe to valve examination geometries and interforences from reactor building structural steel members preclude the complete ultrasonic and liquid penetrant examinations of the volume and the surface area required by Fig. IWB-2500-8.
"For weld TBX-1-4102-7, approximately 61% of the volume and 31% of the surface area did not receive the full code required examination coverage. See pages 3 through 6 for weld location and examination area configuration for weld TBX 4102-7.
"For weld TBX-1-4301-7, approximately 55% of the volume did not receive the full code required examination coverage. See pages 7 through 9 for weld location and examination area configuration for weld TBX 1-4301-7.
"For weld TBX-1-4402-7, approximately 59% of the' volume and 40% of the surface area did not receive the ful! code required examination coverage. See pages 10 through 13 for weld location and examination area configuration for weld TBX 4402-7.
"Best effort examinations were performed for the accessible areas of the weld.
There tvere no recordable indications identified by the best effort volumetric or surface examinations performed.
Licensee's Prooosed Alternative Examination (as stated):
"None - however, 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 the subject l Class 1 piping welds. The licensee provided Limitation to Examination sheets that give
- the layouts and examination coverages of the subject welds. Figures supplied by the l
licensee revealed that component configuration and interference from other components limit access and preclude complete volumetric examination of these welds. In two cases, surface examination is also limited. To meet the Code examination requirements, design modifications would be necessary. Therefore, the Code volumetric and surface examination requirements, as applicable, are impractical for these welds. Imposition of this requirement would create a significant burden on the licensee.
The licensee has examined 39 to 45% of the required volume on three welds, and 60 to 69% of the surface examination coverage on two welds. In addition, these welds are part of a larger sample of B-J welds to be examined. Therefore, reasonable assurance of 6
I. __ _ _ _ .
[.. .
structural integrity is provided by the examinations that have been completed on these
. and other welds within the entire sample.
Based on the impracticality of meeting the Code's volumetric and surface exa"ination requirements for the subject welds, and the reasonable assurance of structural integrity provided by the examinations that were completed, it is recommended that the relief be granted pursuant to 10 CFR 50.55a(g)(6)(i).
E. Reauest for Relief No. B-14. Examination Cateoorv B-J. Item No. B9.31. Branch Connection Welds Code Reauiremeni: Examination Category B-J, Item B9.31 requires 100% volumetric and surface examination, as defined by Figures IWB-2500-910, and 11, for Class 1 branch pipe connection welds in piping 4 inch nominal pipe size and larger.
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 Branch Pipe Connection Weld TBX-1-4404-1.
Licensee's Basis for Reauestina Relief (as stated):
l "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 26% of the examination volume did not receive the full code required coverage.
l "A best effort 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. See pages 2 and 3 for weld location and examination area configuration.
"There were no recordab!e indications identified by the best effort volumetric ;
~
examination or by the required surface examination performed."
Licensee's Proesed Alternative Examination (as stated): ;
"None" i l
Evaluation: The Code requires 100% surface and volumetric examination of the subject Class 1 branch connection welds. The licensee provided Limitation to Examination sheets that give the layouts and examination coverages of the subject weld. Figures supplied by the licensee revealed that component geometry (surface contour of the examination surface) limits access and precludes complete volumetric examination of the subject weld. To meet the Code examination requirements, design modifications would be necessary. Therefore, the Code volumetric examination requirements are impractical for this weld. Imposition of this requirement would create a significant burden on the licensee.
The licensee has examined a significant portion (74%) of the required volume of the weld, and examined 100% of the surface. In addition, this weld is part of a larger sample of B-J 7
l L - - -
L branch connection welds to be examined. Therefore, reasonable assurance of structural l Integrity is provided by the examinations that have been completed on this and other welds within the entire sample.
Based on the impracticality of meeting the Code's volumetric examination requirements for the' subject weld, and the reasonable assurance of structural integrity provided by the examinations that will be completed, it is recommended that relief be granted pursuant to l 10 CFR 50.55a(g)(6)(i).
F. Reauest for Relief No. C-9. Examination Cateaorv C-A. Items C1.10 and C1.20.
Pressure-Retainina Welds in Pressure Vessels l
Code Reauirement: Examination Category C-A, item Numbers C1.10 and C1.20 require 100% volumetric examination, as defined by Figure IWB-2500-1, for Class 2 shell and L head circumferential pressure vessel welds.
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 the following welds.
TBX-21110-1 Excess Letdown Heat Exchanger Head to Flange Weld TBX-2-1180-2-2 Containment Spray Heat Exchanger Phell to Flange Weld
! Licensee's B@is for Reauestina Relief (as stated):
"For weld TBX-2-110-1, interferences frcm the heat exchanger inlet, outlet and instrumentation nozzles and from the flange taper preclude the complete ultrasonic
. examination of the volume required by Fig. IWC-2500-1. Approximately 50% of the weld length did not receive the full code required examination coverage. See l pages 2 through 4 for weld location and examination area configuration for weld )
TBX-2-1110-1. l "For weld TBX-2-1180-2-2, interferences from the heat exchanger welded support pads preclude the complete ultrasonic examination of the volume required by Fig.
lWC-2500-1. Approximately 27% of the weld length did not receiv'e the full code l required examination coverage. See pages 5 through 7 for weld location and I examination area configuration for weld TBX-2-1180-2-2. l
\
"There were no recordable indications identified by the best effort volumetric ,
examination performed on the accessible portions of the weld lengths." )
. Licensee's Proposed Alternative Examination (as stated):
"None" ;
Evaluation: The Code requires 100% volumetric examination of the subject Class 2 pressure vessel welds. The licensee provided Limitation to Examination sheets that give the layouts and examination coverages of the subject welds. Figures supplied by the licensee revealed that the inlet and outlet nozzles, instrumentation nozzles, and component geometry (flange taper) limit access and preclude complete volumetric examination of the subject welds. To meet the Code examination requirements, design 8
'.... , u j I
modifications would be necessary. Therefore, the Code volumetric examination requirements are impractical for the subject welds. Imposition of these requirements .
would create a significant burden on the licensee. l The licensee has examined 50% of the required volume of Weld TBX-2-1110-1 and 73%
of the volume of Weld TBX 2-1180-2 2. Therefore, based on the volumetric coverage obtained, it is concluded that any existing patterns of degradation would have been detected by the examinations that were completed and reasonable assurance of structural integrity has been provided.
Based on the impracticality of meeting the Code examination coverage requirements for the subject welds, and the reasonable assurance provided by the examinations that were completed, it is recommended that relief be granted pursuant to 10 CFR 50.55a(g)(6)(i).
- 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 Comanche Peak Steam Electric Station - Unit 1.
For Requests for Relief B-6 (Rev. 2), B-7 (Rev. 2), B-12, B-13, B-14, and C-9, it is concluded that the Code requirements are impractical. Therefore, it is recommended that relief be granted pursuant to 10 CFR 50.55a(g)(6)(i). >
l I
i 4
9
\
. . -