ML20211A977
| ML20211A977 | |
| Person / Time | |
|---|---|
| Site: | Byron  |
| Issue date: | 09/30/1986 |
| From: | Ainger K COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| 2171K, NUDOCS 8610170096 | |
| Download: ML20211A977 (26) | |
Text
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Commonwealth Edison
/ 72 West Adams Street, Chicago, lilino:s
/ Kddress Reply to: Post Office B~ox767-V Chcago, lilinois 60690 - 0767 September 30, 1986 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555
Subject:
Byron Station Unit 2 Preservice Inspection NRC Docket No. 50-455 Reference (a): July 23, 1986 letter from K. A. Ainger to H. R. Denton
Dear Mr. Denton:
Reference (a) provided the Byron Unit 2 Preservice Inspection Program Plan notes and relief requests. As a result of discussions with the NRC staff and their consultant on September 22, 1986, some program plan notes and relief requests have been revised. Attached to this letter are a summary of the changes and the revised program plan notes and relief requests.
One signed original and fifteen copies of this letter and attachment are provided for NRC review.
Please direct any questions regarding this matter to tiis office.
Very truly yours, K. A. Ainger Nuclear Licensing Administrator 1m Attachment cc: Byron Resident Inspector
.3 \
2171K _, g
Attachment Page 1 of 1 Summary of Changes to Byron Unit 2 Preservice Inspection Program Plan Notes and Relief Request Per Conference Call on September 22, 1986 '
Document Chances Notes 5 and 6 Examination included essentially 100%
(greater than 90.5%) weld length.
Relief Requests NR-1, ASME Code requires the scanning NR-2, NR-3 and NR-12 sensitivity be established using an inner diameter surface notch with a depth of 10% of wall thickness.
Relief Request NR-4 Examination volume is described in Figure IWC-2520-9, not IWC-2500-9.
Relief Request NR-7 Deleted Examination Category B-L-2.
Relief Request NR-8 Deleted Examination Category B-M-1 and B-M-2.
Relief Request NR-11 Corrected Examination Category to B-D.
Relief Request NR-13 Examination volume is described in Figure IWC-2520-4, not IWC-2500-4.
Relief Request NR-15 Deleted Examination Category Item C1.lO.
Note 5 Rev. 1 NorE 5 Limited Class 1 Examinations SYSTEM: Safety Injection NUMBER OF ITEMS: 4 ASME CODE CLASS: 1 PERTINENT CODE REQUIREMENTS: Examination Category B-J, Item B9.ll requires a surface and volumetric examination of the volume described in figure IWB-2500-8. The volumetric examination performed during the inspection interval shall cover all the area of 25% of the circumferential joints. The examination includes at least a pipe diameter length, but not more than 12 inches of each longitudinal weld intersecting the circumferential welds required to be examined.
IWB-2200 states, " Examinations required by this article shall be completed prior to initial plant startup. In addition, these preservice examinations shall be extended to include essentially 100% of the pressure retaining welds in Class 1 components, except in those components exempted from examination by IWB-1220."
LIMITATION OF EXAMINATION: Essentially 100% (greater than 90.5%) of the weld length of the circumferential welds listed below was examined by volumetric techniques. 100% of the required weld volume was examined by a complete circumferential scan. However, a small percentage of each weld (in no case greater than 8.29%) was not examinable by an axial half-v-path or full-y-path scan.
In all cases below, a surface examination (liquid penetrant) and a visual examination (leak test) will be performed.
Line Weld Blocked By % Missed Attachment 25I098A-10" J18 Ganaa Plug 6.29* 1 25IO98A-10" J27 Gamma Plug 6.29* 2 25IO9BD-10" J1 Branch Connection 8.29* 3 25IO9BD-10" J25 Gamma Plug 6.66* 4 Note: *In all cases above, the percentage missed is a conservative estimate as shown on Attachment 5 to this note.
The procedure for axially scanning these welds requires that the transducer be twisted back and forth while scanning. As a result, more volume is actually examined than that reflected by the above numbers.
(0950M/0095M) o
Note 6 Rev. 1 NOTE 6 Limited Class 2 Examinations SYSTEM: Safety Injection NUMBER OF ITEMS: 2 ASME CODE CLASS: 2 PERTINENT CODE REQUIREMENTS: Examination Category C-F, Item C5.21 requires both surface and volumetric examinations of the regions described in Figure IWC-2520-7 for circumferential welds in piping over 1/2 in.
nominal wall thickness. Subarticle IWC-2200 requires completion of all examinations required by its article, once, prior to initial plant startup.
DESCRIPTION OF EXAMINATION: Essentially 100% (greater than 90.5%) of the weld length of the circumfe.rential welds listed below was examined by volumetric techniques. 100% of the required weld volume was examined by a complete circumferential scan. However, a small percentage of each weld (in no case greater than 7.49%) was not examinable by an axial half-y-path or full-v-path scan.
In all cases below, a surface examination (liquid penetrant) and a visual examination (leak test) will be performed.
Line Weld Blocked By % Missed Attachment 2SIO4B-12" Cl Sockolet 7.49* 1 2SIO6BA-24" C1 Gamma Plug 2.98* 2 Note: *In all cases above, the percentage missed is a conservative estimate as shown on Attachment 3 to this note.
The procedure for axially scanning these welds requires that the transducer be twisted back and forth while scanning. As a result, more volume is actually examined than that reflected by the above numbers.
1 1
1 (0950M/0095M) ,
NR-1 Rev. 1 RELIEF REQUEST NR-1
- 1. SYSTEM: Reactor Coolant
- 2. NUMBER OF ITEMS: 8 Cast Stainless Steel SA-351-CF8A (Elbow) to Cast Stainless Steel SA-351 '2F8 (Pump)
Line Number Weld Number Attachment Numbers 2RCO2AA-31" J-8 1&2 2RC02AB-31" J-8 1&2 2RCO2AC-31 J-8 1&2 2RCO2AD-31 J-8 1&2 Cast Stainless Steel SA-351-CF8A (Elbow) to Cast Stainless Steel SA-351-CF8M (Valve)
Line Number Weld Number Attachment Numbers 2RC01AA-29" J-4 1&3 2RC01AB-29" J-4 1&3 2RC01AC-29" J-4 1&3 2RC01AD-29" - J-5 1&3
- 3. ASME CODE CLASS: 1
- 4. ASME CODE SECTION XI REQUIREMENTS: Tal,le IWB-2500-1, Examination Category B-J, Item 89.11 requires a surface and wlumetric examination of the regions described in Figure INB-2500-8 for piping 4 in. nominal pipe size and greater. In addition, Examination Category B-P, Item B15.50 requires a system leakage test in accordance with INB-5221 each refueling outage for all pressure retaining components. Article IW9-2200, "Preservice s Examination" states that:
- a. Examinations required by this Article shall be completed prior to initial plant startup. In addition, the preservice examinations shall be extended to include essentially 100% of the pressure retaining welds in all Class 1 components except in those components exempted from examination by IWB .1220 (a), (b),
or (c).
- b. Shop and fleid examinations may serve in lieu of the on-site preservice examination provided:
- 1) In the case of vessels only, the examination is performed after the hydrostatic test required by Section III has been completed
- 2) such examinations are conducted under conditions and with equipment and techniques equivalent to those that are expected to be employed for subsequent inservice inspections; (0946M/0095M)
NR-1 Rev. 1
- 3) the shop and field examinations records are, or can be, documented and identified in a form consistent with those i required in IWA-6000.
For angle beam calibration, Mandatory Appendix III, Supplement 7, requires for ultrasonic examination of austenitic welds that the scanning sensitivity be established using an I.D. notch with a depth of 10% of wall thickness.
- 5. BASIS FOR RELIEF: All of the welds listed above are cast austenitic stainless steel to cast austenitic stainless steel. Acceptable radiographic examinations of these welds have been completed to meet the preservice volumetric inspection requirement. However, we do not intend to use radiography as the inservice volumetric examination method.
A "best effort" ultrasonic examination, consisting of the code required axial 1/2 V-path scan from both sides of the weld and circumferential 1/2 V-path scan along the weld, was completed for each of the above listed welds. However, the code required sensitivity was not attainable due to the attenuation characteristics of cast austenitic stainless steel. In addition, the unwieldy characteristics of the contoured wedge search unit and the valve body contour on the O.D. surface presented some limitations during the axial scans (except weld J5 on line 2RC01AD-29" which had no examination restrictions). Circumferential scans were limited a short l
distance from the edge of the weld crown for both the valve and pump welds because of the search unit dimensions and the physical shape of these i castings. These restrictions precluded the 100% examination coverage as required by the procedure.
- 6. ALTERNATE TEST METHOD: None.
- 7. JUSTIFICATION: The examinations performed on the above listed welds represent the state-of-the-art, best effort, technique available for the inspection of cast austenitic stainless steel. The ultrasonic inspection technique utilizes two 1.0 inch diameter x 1.0 MHz transducers, mounted on a contoured wedge search unit, that produce an approximate 41 degree, dual, refracted longitudinal wave focused near the calibration block I.D.
surface. The calibration standards were machined from a representative cast stainless steel elbow. The ultrasonic examination technique was proven capable of penetrating ultrasound to the weld I.D. and detecting large flaws (25% or greater through wall dimension) in the cast material.
Despite the reported limitations, both axial and circumferential scans were capable of locating flaws within the counterbore region as verified by the identification of root and counterbore signals. This counterbore region (See Attachments) closely resembles the ASME Code required examination volume and thus is the primary area of interest for volumetric flaw detection. The combination of acceptable radiographic examinations and these state-of-the-art ultrasonic examinations assures an acceptably high level of structural integrity for these welds.
(0946M/0095M) 0
NR-2 Rev. 1 RELIEF REQUEST NR-2
- 1. SYSTEM: Reactor Coolant
- 2. NUMBER OF ITEMS: 4 Cast Stainless Steel.SA-351-CF8A (Elbow) to Stainless Steel SA-182 GR-F316 (Safe-end)
Line Number Weld Number Attachment Number 2RC03AA-27.5" J-12 1&2 2RC03AB-27.5" J-12 1&2 2RC03AC-27.5" J-13 1&2 l
2RC03AD-27.5" J-12 1&2 j 1 1
- 3. ASME CODE CLASS: 1 i
- 4. ASME CODE SECTION XI REQUIREMENTS: Table IWB-2500-1, Examination Category B-J, Item B9.11 requires surface and volumetric examination of the regions described in Figure IWR-2500-8 for piping 4 in, nominal pipe sise and greater. In addition, Examination Category B-P, Item B15.50 requires a leakage test in accordance with IWB-5221 each refueling outage for all pressure retaining components.
Article IWB-2200 "Preservice Examination" states that:
- a. Examinations required by this Article shall be completed prior to initial plant startup. In addition, the preservice examinations shall be extended to include essentially 100% of the pressure retaining welds in all Class 1 components except in those components exempted from examination by IWB-1220 (a), (b) or (c).
- b. Shop and field examinations may serve in lieu of on-site preservice s examination provided:
- 1) In the case of vessels only, the examination.1,s performed after the hydrostatic test required by Section III has been completed;
- 2) such examinations are conducted under conditions and with I
equipment and techniques equivalent to those that are expected to be employed for subsequent inservice inspections;
- 3) the shop and field examination records are, or can be, documented and identified in a form consistent with those required in IWA-6000.
Ultrasonic examination requirements from Mandatory Appendix III, Article III-4000, require examination for:
- a. reflectors parallel to the weld seam. The angle beam examination for reflectors parallel to the weld seam shall be performed by a full V path from one side or a one-half V path f rom two sides of the weld, where practicable.
(0946M/0095M) s
NR-2 Rev. 1 l b. reflectors transverse to the weld seam.
l 1) The angle beam examination for reflectors transverse to tre weld seam shall be performed on the weld crown on a single scan path j to examine the weld root by one-half V path in two directions along the weld.
, 2) For inservice examination, only those welds showing reportable l preservice indications need be examined for transverse reflectors.
For angle beam calibration, Mandatory Appendix III, Supplement 7, requires for ultrasonic examination of austenitic welds that the scanning sensitivity be established using an I.D. notch with a depth of 10% of wall i thickness.
- 5. BASIS FOR RELIEF: The welds listed above are all cast austenitic stainless steel to Reactor Vessel nozzle safe-ends. These welds have received radiographic and surface examinations to meet the preservice
- . volumetric and surface examination requirements. However, we do not j intend to use radiography as the inservice volumetric examination method.
I Ultrasonic examinations were performed circumferential1y in both directions for transverse reflectors, and axially for parallel reflectors, i
from the safe-end side only, on each of the above listed welds. In addition, a "best effort" ultrasonic examination, consisting of l circumferential 1/2 V-path scans of the elbow side base metal, was
! performed. The unwieldy characteristics of the contoured wedge search l unit and the as-cast transition on the elbow 0.D. surface prevented
, performance of an axial scan from the elbow side. The elbow side 4
circumferential scans were limited a short distance from the edge of the weld crown due to the inability of the search unit to maintain sufficient l coupling while scanning over the weld to base metal transition. The code
- required sensitivity was, also, not attainable on the elbow side due to j the attenuation characteristics of cast austenitic stainless steel. These l restrictions precluded the 100% examination coverage as required by the procedure.
- 6. ALTERNATE TEST MRTHOD: None.
{ _
- 7. JUSTIFICATION: The examinations performed from the cast (elbow) side of the above listed welds represent the state-of-the-art, best effort,
! technique available for the inspection of cast austenitic stainless j steel. The ultrasonic inspection technique utilises two 1.0 inch diameter
- x 1.0 Mis transducers, mounted on a contoured wedge search unit, that produce an approximate 41 degree, dual, refracted longitudinal wave
- focused near the calibration block I.D. surface. The calibration j standards were machined from a representative cast stainless steel elbow.
l The ultrasonic examination technique was proven capable of penetrating ultrasound to the weld I.D. and detecting large flaws (25% or greater
- through wall dimension) in the cast material. The circumferential scans i were capable of locating flaws in the volume of metal adjacent to the i weld, near the I.D. surface. Having performed acceptable radiographic and j one-sided ultrasonic (from the safe-end side) examinations as well as the
! state-of-the-art ultrasonic examination (from the elbow side), an
! acceptably high level of structural integrity for these welds is assured.
1 (0946M/0095M) )
0
NR-3 Rev. 1 RELIEF REQUEST NR-3
- 1. SYSTEM: Reactor Coolant
- 2. NUMBER OF ITEMS: 8 Cast Stainless Steel SA-351-CF8A (Elbow) to Cast Carbon Steel SA-216 GR-WCC (Nozzle)
Line Number e Weld Number Attachment Numbers 2RC01AA-29" F-2 1&2 2RCO2AA-31" F-1 1&2 2RC01AB-29" F-2 1&2 2RCO2AB-31" F-1 1&2 2RC01AC-29" F-2 1&2 2RCO2AC-31" F-1 1&2 2RC01AD-29" F-2 1&2 2RCO2AD-31" F-1 1&2
- 3. ASME CODE CLASS: 1 4
- 4. ASME CODE SECTION XI REQUIREMENTS: Table IWB-2500-1, Examination Category B-F, Item B5.30 requires surface and volumetric examination of the regions described in Figure IWB-2500-8 for all Steam Generator nozzle-to-safe end welds. In addit-lon, Examination Category B-P, Item B15.30 requires a system leakage test in accordance with IWB-5221 each refueling outage for the steam generator pressure retaining boundary.
Article IWB-2200, "Preservice Examination", states that:
t
- a. Examinations required by this Article shall be completed prior to initial plant startup. In addition, the preservice examinations shall be extended to include essentially 100% of the pressure retaining welds in all Class 1 components except in those components exempted from examination by IWB-1220 (a), (b) or (c).
- b. Shop and field examinations may serve in lieu of on-site preservice examinations provided:
- 1) In the case of vessels only, the examination is performed after the hydrostatic test required by Section III has been completed:
- 2) such examinations are conducted under conditions and with equipment and techniques equivalent to those that are to be
! employed for subsequent inservice inspections;
- 3) the shop and field examination records are, or can be, documented and identified in a form consistent with those required in IWA-6000.
! Ultrasonic examination requirements from Mandatory Appendix III, Article i III-4000, require examination for:
(0946M/0095M) e a
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NR-3 Rev. 1
- a. Reflectors parallel to the weld seam. The angle beam examination for
- reflectors parallel to the weld seam shall be performed by a full V i path from one side or a one-half V path from two sides of the weld, j where practicable.
- b. Reflectors transverse to the weld seam.
! 1) The angle beam examination for reflectors transverse to the1 weld seam shall be performed on the weld crown on a single scan path to examine the weld root by one-half V path in two directions i
along the weld.
For inservice examination, only those welds showing reportable 2) preservice indications need be examined for transverse 4 reflectors.
i For angle beam calibration, Mandatory Appendix III, Supplement 7, requires
. for ultrasonic examination of austenitic welds that the scanning i sensitivity be established using an I.D. notch with a depth of 10% of wall thickness.
- 5. BASIS FOR RELIEF: The welds listed above are cast austenitic stainless I steel SA-351-CF8A to cast carbon steel SA-216 GR-WCC with austenitic
, stainless steel cladding. Acceptable radiographic examinations of these welds have been completed to meet the preservice volumetric inspection
~
l requirement. However, we do not intend to use radiography as the j inservice volumatric examination method.
Ultrasonic examinations were performed circumferential1y in both '
directions for transverse reflectors, and axially for parallel reflectors, from the steam generator nossle side with a 1/2 V-path scan. In addition, 4 a "bsst effort" ultrasonic examination, consisting of the code required axial 1/2 V-path scan from the elbow side and circumferential 1/2 V-path scans along the weld, was completed for each of the above listed welds.
3 However, the code required sensitivity was not attainable on the elbow
- side due to the attenuation characteristics of cast austenitic stainless i steel. The elbow side circumferential scans were limited a short distance from the edge of the weld crown due to the inability of the search unit to maintain sufficient coupling while scanning over the weld to base metal
- transition. These , restrictions precluded the 100% examination coverage as l required by the procedure. ;
1
- 6. ALTERNATE TEST METHOD: None.
1 l
4
! (0946M/0095M)
I s*
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-- . - - - . . . , - . ,.~.-.,--,.n,-----. . _ _ n.-n n., .--,._n.~-_,-,--r-..
4 4
NR-3 Rev. 1 1
- 7. JUSTIFICATION: The examinations performed from the elbow side of the
- above listed welds represent the state-of-the-art, best effort, technique available for the inspection of cast austenitic stainless steel. The ultrasonic inspection technique utilizes two 1.0 inch diameter x 1.0 MHz transducers, mounted on a contoured wedge search unit, that produce an approximate 41 degree, dual, refracted longitudinal wave focused near the calibration block I.D. surface. The calibration standards were machined
- from a representative cast stainless steel elbow. The ultrasonic examination technique was proven capable of penetrating ultrasound to the weld I.D. and detecting large flaws (25% or greater through wall dimension) in the cast material. Despite the reported limitations, both axial and circumferential scans were capable of locating any flaws within the counterbore region as vocified by the identification of root and counterbore signals. This counterbore region (See Attachments) closely resembles the ASME Code required examination volume and thus is the primary area of interest for volumetric flaw detection. The combination of acceptable radiographic examinations, acceptable ultrasonic examinations from the steam generator side, and these state-of-the-art ultrasonic. examinations from the elbow side assures an acceptably high level of structural integrity for these welds.
l I
i i
_3 (0946M/0095M) s
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NR-4 Rev. 1 RELIEF REQUEST NR-4
- 01. SYSTEM: Main Steam, Safety Injection and Residual Heat Removal
- 2. NUMBER OF ITEMS: 24; Line Number Weld Number Attachment 2MS07AA-28" C-12, C-13, C-14, C-15 and C-16 1 2MS07AB-28" C-15, C-16, C-17, C-18 and C-19 2 2MS07AC-28" C-15, C-16, C-17, C-18 and C-19 3 2MS07AD-28" C-12, C-13, C-14, C-15 and C-16 4 ,
2SIO6BA-24" C-26 5 l 2SIO6BB-24" C-26 6 1 2RH01CA-16" C-1L 5 2RHOICB-16" C-lL 6
- 3. ASME CODE CLASS: 2
- 4. ASME CODE SECTION XI REQUIREMENTS: Examination Category C-F, Items C5.31 and C5.32, require a surface examination of the volume described in Figure IWC-2520-9. The required volume is 100% of each circumferential weld l requiring examination and 2.5t of the longitudinal weld at the intersecting circumferential weld. IWC-2200 states:
a) All examinations required by this article for those components initially selected for examination in accordance with Inspection Program A or Inspection Program B and not exempt from inservice examinations by IWC-1220 shall be completed prior to initial plant startup, b) Shop and field examinations may serve in lieu of the on-site preservice examinations, provided:
- 1) in the case of vessels only, the hydrostatic test required by Section III has been completed;
- 2) such examinations are conducted under conditions and with equipment and techniques equivalent to those which are expected to be employed for subsequent inservice examinations;
- 3) the shop and field examination records are or can be documented and identified in a form consistent with those required in INA-6000."
- 5. BASIS FOR RELIEF: The above listed welds are inaccessible to surface examinations, due to the location of saddle plates over the pressure retaining welds. The welds are depicted on attachments 1 through 6 as indicated above.
- 6. ALTERNATE TEST METHOD: A surface examination, (liquid penetrant) and visual examination (leak test) will be performed on the saddle plate fillet welds in lieu of the required surface examinatione for the pressure retaining welds listed above.
(0946M/0095M) s
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NR-4 Rev. 1
- 7. JUSTIFICATION: Performing a surface and visual examination of the saddle plate fillet welds provides an acceptable level of structural integrity for system operation. Radiographs performed on the branch pipe circumferential welds verify its structural integrity at the time of construction. Therefore, an adequate level of plant operational safety can be assured on these welds.
(0946M/0095M)
NR-7 Rev. 1 RELIEF REQUEST NR-7
- 1. SYSTEM: Reactor Coolant, Reactor Coolant Pressurizer, Safety Injection, and Residual Heat Removal.
- 2. NUMBER OF ITEMS: 41 Reactor Coolant 2EC8001-A 2RC8002-A 2RC8003-A 2RC8001-B 2RC8002-B 2RC8003-B 2RC8001-C 2RC8002-C 2RC8003-C 2RC8001-D 2RC8002-D 2RC8003-D Pressurizer 2RY8010-A 2RY8010-B 2RY8010-C Residual heat Removal 2RH8701-A 2RH8702-A 2RH8701-B 2RH8702-B 1 <
Safety Injection 2SI8808-A 2SI8818-A 2SI8841A 2SI8808-B 2SI8818-B 2SI8841B 2SI8808-C 2SI8818-C 2SI8808-D 2SI8818-D 2SI8948-A 2SI8949-A 2SI8956-A 2SI8948-B 2SI8949-B 2SI8956-B 2SI8948-C 2SI8949-C 2SI8956-C 2SI8948-D 2SI8949-D 2SI8956-D
- 3. ASME CODE CLASS: 1
- 4. ASME CODE SECTION XI REQUIREMENT: Examination Category B-M-2, Item B12.40 l j requires a visual, (VT-1) examination of the valve body internal surfaces s on valves exceeding 4 inches nominal pipe size. Examinations are limited i to one valve within each group of valves that are of the same constructional design, e.g. globe, gate or check valve, manufacturing method and that are performing similar functions in the system, e.g.
containment isolation, system overpressure protection. ,
- 5. BASIS FOR RELIEF: The requirement to disassemble an operable valve for the sole purpose of performing a visual examination (VT-1) of the internal pressure retaining boundary is impractical and not conunensurate to the increased safety achieved by this inspection. Class 1 valves are g- installed in their respective systems and many have completed functional testing. To disassemble these valves would provide a very small potential i for increasing plant safety margins with a very disproportionate impact on expenditures of plant manpower and resources.
l (0946M/0095M) '
l 0
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l NR-7 Rev. 1
- 6. ALTERNATE TEST METHOD: The manufacturers test data will be used in lieu of a preservice visual examination (VT-1). This includes documentation of examinations performed during fabrication and installation of the subject valves. The examinations performed may include volumetric, surface, and !
visual exams, as required by ASME Section II, Material Specifications for Ferrous and Nonferrous materials.
- 7. JUSTIFICATION: The integrity of the pressure retaining boundary of both carbon steel and stainless steel valve bodies has been excellent. Class 1 valve bodies can not historically be linked to breaching of the pressure retaining boundary in plant systems. Class 1 valves are subjected to numerous types of nondestructive testing and a rigorous quality assurance program during all stages of fabrication, storage, and installation.
These valves have been found acceptable by the Manufacturer, the ASME Authorized Nuclear Inspector and Commonwealth Edison's Quality Assurance.
e N
==
(0946M/0095M)
O
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- NR-8 Rev. 1 RELIEF REQUEST NR-8
- 1. SYSTEM: Reactor Coolant Pumps
- 2. NUMBER OF ITEMS: 4 (2RC0lPA, 2RC0lPB, 2RC0lPC, 2RC0lPD) l
- 3. ASME CODE CLASS: 1
- 4. ASME CODE SECTION XI REQUIREMENTS
- Examination Category B-L-1, " Pressure Retaining Welds in Pump Casings," Item B12.10 requires a volumetric and surface examination of the regions described in Figure IWB-2500-16.
Examination Category B-L-2, " Pump Casings," Item B12.20 requires a visual examination of the internal surfaces. Subarticle IWB-2200 requires completion of all examinations required by its Article, once, prior to initial plant Startup.
- 5. BASIS FOR RELIEF: The requirement to disassemble an operable pump for the sole purpose of performing a visual examination (VT-1) of the internal j pressure retaining boundary is impractical and not commensurate to the increased safety achieved by this inspection. To disassemble these pumps would provide a very small potential for increasing plant safety margins with a very disproportionate impact on expenditures of plant manpower and resources.
- 6. ALTERNATE TEST METHOD: The above listed pumps are of the integrally cast type and, therefore, have no pump casing welos. All internal surfaces, received liquid penetrant tests performed by the manufacturer. This exceeds the Section XI requirements for visual examination.
- 7. JUSTIFICATION: The Reactor Coolant Pump casing is cast austenitic
, stainless steel, which is extremely tough and resistant to intergranular stress corrosion cracking. The combination of these material properties and the liquid penetrant test performed by the manufacturer assures an acceptable level of structural integrity. In addition, these pumps are subjected to numerous types of nondestructive testing and a rigorous quality assurance program during all stages of fabrication, storage, and installation. These pumps have been found acceptable by the Manufacturer, the Authorized Nuclear Inspector and Commonwealth Edison's Quality Assurance.
l l
I i
(0946M/0095M) ,
NR-ll Rev. 1 )
l RELIEF REQUEST NR-11
- 1. SYSTEM: Reactor pressure Vessel
- 2. NUMBER OF ITEMS: 4 Weld Number Attachment Number RPVN-A,D,E and H 1, 2, 3 & 4
- 3. ASME CODE CLASS: 1
- 4. ASME CODE SECTION XI REQUIREMENTS: Table IWB-2500-1, Examination Category B-D, Item B3.90 requires volumetric examination of the regions described l in Figure IWB-2500-7 for full penetration welds of nozzles in vessels. In addition, examination Category B-p, Item B15.50 requires a system leakage test, IWB-5221 each refueling outage for the reactor pressure retaining components.
Article IWB-2500-1, "preservice Examination" states that:
- a. Examinations required by this Article shall be completed prior to initial plant startup. In addition, the preservice examination shall be extended to include essentially 100% of the pressure retaining welds in al-1 Class 1 components except in those components exempted from examination by IWB-1220 (a), (b) or (c).
- b. Shop and field examinations may serve in lieu of the on-site preservice examinations provided:
- 1) In the case of vessels only, the examination is performed after the hydrostatic test required by Section III has been completed;
- 2) Such examinations are conducted under conditions and with equipment and techniques equivalent to those 4 hat are expected to be employed for subsequent inservice examinations; and
- 3) The shop and field examination records are, or can be, documented and identified in a form consistent with those required in IRA-6000.
- 5. BASIS FOR RELIEF: No zzle-to-vessel welds on outlet nozzles A, D, E and H are obstructed by the integral extension from receiving complete ultrasonic examination. The required volume was inspected for parallel reflectors from the ID surface of the nozzle, however, approximately 15%
of the required base metal was not inspected for transverse reflectors from the vessel side as shown in Attachments 2 and 3. In addition, Attachment 4 provides an estimate of the near surface volume not effectively examined.
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NR-11 Rev. 1
- 7. JUSTIFICATION: Completion of the required examination is impractical and would result in undue hardship without a compensating increase in safety.
The limited Section XI examination, the volumetric examination performed during fabrication, and the hydrostatic test demonstrate an acceptable level of preservice structural integrity.
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NR-ll Rev. 1 Estimate of the Extent of Near Surface Volume not Effectively Examined Base Metal Near Weld Designation Transducer Surface Not Examined (inches)
Examination of Nozzle-to-Vessel 0* Laminar and Planar 1.6 Welds (8)
J 1
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Attachment 4 NR-ll i
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NR-12 Rev. 1 RELIEF REQUEST hT-12
- 1. SYSTEM: Reactor Coolant
- 2. NUMBER OF ITEMS: 36 Cast Stainless Steel SA-351-CF8A (Elbow) to Stainless Steel SA-376 Type 304N (Pipe)
Line Number Weld Numbers Attachments Numbers 2RC02AA-31" J-1, J-2, J-3, J-7 1&2 2RCO2AB-31" J-1, J-2, J-3, J-7 1&2 2RCO2AC-31" J-1, J-2, J-3, J-7 1&2 2RCO2AD-31" J-1, J-2, J-3, J-7 1&2 2RC03AA-27.5" J-ll 1&2 2RC03AB-27.5" J-11 1&2 2RC03AC-27.5" J-12 1&2 2RC03AD-27.5" J-11 1&2 Cast Stainless Steel SA-351-CF8 (Pump) to Stainless Steel SA-376 Type 304N (Pipe)
Line Number Weld Numbers Attachment Numbers 2RC03AA-27.5 J-1 1&3 2RC03AB-27.5 J-1 1&3 2RC03AC-27.5 J-l 1&3 2RC03AD-27.5 J-l 1&3 Cast Stainless Steel SA-351-CF8M (Valve) to Stainless Steel SA-376 Type 304N (Pipe)
Line Number Weld Number "-
Attachment Number 2RC01AA-29" J-3 1&4 2RC01AB-29" J-3 1&4 2RC01AC-29" J-3 1&4 2RC01AD-29" J-4 1&4 2RC03AA-27.5" J-5, J-6 1&4 2RC03AB-27.5" J-5, J-6 1&4 2RC03AC-27.5" J-5, J-6 1&4 2RC03AD-27.5 J-4, J-5 1&4
- 3. ASME CODE CLASS: 1 (0946M/0095M) e
NR-12 Rev. 1
- 4. ASME CODE SECTION XI REQUIREMENTS: Table IWB-2500-1, Examination Category B-J, Items B9.ll and B9.12 require surface and volumetric examination of the regions described in Figure IWB-2500-8 for piping 4 in. nominal pipe size and greater. In addition, Examination Category B-P, Item B15.50 requires a system leakage test, IWB-5221, each refueling outage for all pressure retaining components.
Article IWB-2200, "Preservice Examination" states that:
- a. Examinations required by this Article shall be completed prior to initial plant startup. In addition, the preservice examination shall i
be extended to include essentially 100% of the pressure retaining welds in all Class 1 components except in those components exempted from examination by IWB-1220 (a), (b), or (c).
- b. Shop and field examinations may serve in lieu of on-site preservice examinations provided:
- 1) In the case of vessels only, the examination is performed after I the hydrostatic test required by Section III has been completed;
- 2) such examinations are conducted under conditions and with equipment and techniques equivalent to those that are expected i to be employed for subsequent inservice inspections; i ,
- 3) the shop and field examination records are, or can be, docume'nted and identified in a form consistent with those required in INA-6000, i
Ultrasonic examination requirements from Mandatory Appendix III, Article III-4000 require examination for:
- a. Reflectors parallel to the weld seam.
The angle beam examination for reflectors parallel to the weld seam shall be performed by a full V-path from one side or a one-half
^
V-path from two sides of the weld, where practicable.
- b. Reflectors transverse to the weld seam
- 1) The angle beam examination for reflectors transverse to the weld seam shall be performed on the weld crown on a single scan path to examine the weld root by one-half V-path in two direction along the weld.
- 2) For inservice examination, only those welds showing reportable preservice indications need be examined for transverse reflectors.
For angle beam calibration, Mandatory Appendix III, Supplement 7, requires for ultrasonic examination of austenitic welds that the scanning sensitivity be established using an I.D. notch with a depth of 10% of wall thickness.
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NR-12 Rev. 1
- 5. BASIS FOR RELIEF: The welds listed above are all cast austenitic stainless steel to stainless steel pipe. We have completed acceptable radiographic and surface examinations to meet the preservice volumetric and surface requirements. However, we do not intend to use radiography as the inservice volumetric examination method.
Ultrasonic examinations were performed circumferentially in both directions for transverse reflectors, and axially for parallel reflectors, from the pipe side with a 1/2 V-path scan. In addition, a "best effort" ultrasonic examination, consisting of the code required axial 1/2 V-path scan from the component (elbow, pump, or valve) side and circumferential 1/2 V-path scans along the weld, was completed for each of the above listed welds. However, the code required sensitivity was not attainable on the component side due to the attenuation characteristies of cast austenitic stainless steel. The axial scans of welds J1 and J5, on lines 2RC02AB-31" and 2RC03AB-27.5" respectively, were limited by 3% due to base metal concavity (J1) and a permanent support (J5). The unwieldy characteristics of the contoured wedge search unit and the valve body contour on the O.D. surface presented some limitations during the axial scans of the pipe-to-valve welds. Circumferential scans were limited a short distance from the edge of the weld crown for all the pipe-to-valve welds, all the pipe-to-pump welds, and three of the pipe-to-elbow welds (2RCO2AA-31"/J1, 2RCO2AB-31"/J1, and 2RCO2AC-31"/J3) because of the inability of the search unit to maintain sufficient coupling while scanning over the weld to base metal transition. These restrictions precluded the 100% examination coverage as required by the procedure.
- 6. ALTERNATE TEST METHOD: Nona
- 7. JUSTIFICATION: The examinations performed from the component side of the above listed welds represent the state-of-the-art, best effort, technique available for the inspection of cast austenitic stainless steel. The ultrasonic inspection technique utilizes two 1.0 inch diameter x 1.0 MHz transducers, mounted on a contoured wedge search unit, that produce an approximate 41 degree, dual, refracted longitudinal wave focused near the calibration block I.D. surface. The calibration standards were machined from a representative cast stainless steel elbow. The ultrasonic examination technique was proven capable of penetrating ultasound to the weld I.D. and detecting large flaws (25% or greater through wall i dimension) in the cast material. Despite the reported limitations, both j axial and circumferential scans were capable of locating flaws within the I counterbore region as verified by the identification of root and counterbore signals. This counterbore region (Sec Attachments) closely resembles the ASME Code required examination volume and thus is the primary area of interest for volumetric flaw detection. The combination of acceptable radiographic examinations, acceptable ultrasonic examinations from the pipe side, and these state-of-the-art ultrasonic examinations from the component side assures an acceptably high level of l structural integrity for these welds. l 1
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NR-13 Rev. 1 RELIEF REQUEST NR-13
- 1. SYSTEM: Steam Generator Vessel (Secondary Side) Nozzles, Residual Heat Exchanger Nozzles
- 2. NUMBER OF ITEMS: 10 Component Number Nozzle Number 2RC01BA SGN-02,03 2RC01BB SGN-02,03 2RC01BC SGN-02,03 2RC01BD SGN-02,03 2RH02AA RHXN-01,02
- 3. ASME CODE CLASS: 2
- 4. ASME CODE SECTION XI REQUIREMENTS: Table IWC-2500-1, Examination Category, C-B, Item C2.20 requires surface and volumetric examination of the regions described in Figure IWC-2520-4 for nozzles in vessels over 1/2 in. In nominal thickness. Figure IWC-2520-4 requires volumetric examination of the inner radii on nozzles over 12 in, nominal pipe size.
In addition, Examination Category C-H, Item C7.10 requires a system leakage test, IWC-5221, each inspection period for all pressure vessel pressure retaining components.
Subarticle IWC-2200 "Preservice Inspection" states that:
- a. All examinations required by this Article for those components initially selected for examination in accordance with Inspection Program A or Inspection Program B and not exempted from inservice examination by IWC-1220 shall be completed prior to initial plant startup.
- 5. BASIS FOR RELIEF: The nozzles listed above contain inherent geometric constraints which limit the ability to perform meaningful ultrasonic examinations. The main steam nozzles- (SGN-03's) have an internal multiple venturi type flow restrictor, see Attachment 1. This design does not have a nozzle inner radii as described in Figure IWC-2520-4. This nozzle has l seven individual inner radii, corresponding to each venturi, none of which could be examined by ultrasonic examination. The main feedwater nozzles (SGN-02's) also have an internal multiple venturi type flow restrictor but have a thermal sleeve in addition, see Attachment 2. This design could not be examined due to the geometry of the nozzles internal design.
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NR-13 Rev. 1 The Residual Heat Removal Heat Exchanger is approximately 7/8 in. nominal wall thickness with nozzles of 14 inch diameter and approximately 3/8 in.
in nominal wall thickness. Attachment 3 shows the actual nozz le-to-shell weld configuration for the Residual Heat Removal Heat Exchangers primary side nozzles. This configuration is best characterized as a fillet welded nozzle and, thereby, is not analogous to a full penetration butt welded nozzle as shown in Figure IWC-2520-4. In addition, the inner radius of the reinforcement pad would be representative of the nozzle inner radius required for inspection. The inherent gecmetric constraints of the nozzle design prevent the performance of the required ultrasonic examinations of the nozzle-to-shell weld and the nozzle inner radius.
- 6. ALTERNATE TEST METHOD: Ultrasonic examination of the above listed nozzle inner radii is not practicable and the inner radii is not accessible to direct contact for surface examination or even remote visual examination.
However, the Steam Generator (Secondary Side) Nozzles have been examined at the point of attachment to the vessel by radiography per ASME Section III, and by ultrasonic examination per ASME Section XI. The Residual Heat Removal Heat Exchanger Nozzles have been examined by radiography per ASME Section III, and by surface examination per ASME Section XI. In addition, a system hydrostatic test, at 125% of the design pressure, has been performed in accordance with ASME Section III and a system leakage test, at 100% of the system nominal operating pressure, will be performed each inspection period in accordance with ASME Section XI.
- 7. JUSTIFICATION: -The above listed main steam and main feedwater nozzles are designed with multiple venturi type ficw restrictors to limit flow during a Main Steam line or Main Feedwater line break. This design thus enhances the plant's inherent level of safety but does not allow meaningful ultrasonic examination of the nozzles inner radii. However, the increased safety margin afforded by these nozzles makes them a desirable part of plant design. The actual nozzle-to-shell weld configuration of the Residual Heat Removal Heat Exchanger nozzles is most closely approximated by Figure IWC-2500-4(c) of the 1980 Edition, Winter 1981 Addenda of Section XI. The examination requirement associated with this figure, with the inside of the vessel inaccessible, is a surface examination of the nozzle-to-shell weld. Therefore, it is believed the performance of the surface examination meets the intent of Section XI relative to the examination requirements for a fillet welded nozzle. In performing the ASME Section III inspections and the ASME Section XI ultrasonic and/or surface examinations of the point of attachment to the vessel, along with the inservice leakage test, an adequate level of structural integrity for these nozzles is assured for plant operation.
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i 1
I NR-15 Rev. 1 RELIEF REQUEST NR-15
- 1. SYSTEM: Chemical and Volume Control, Excess Letdown Heat Exchanger
- 2. NUMBER OF ITEMS: 1 1
Component Number Weld Number Attachrtent Number I l
2CV01AA ELHXC-03 1&2 j
- 3. ASME CODE CLASS: 2
- 4. ASME CODE SECTION XI REQUIREMENTS: Table IWC-2500-1, Examination Category C-A, Item C1.20 requires volumetric examination of the regions described in Figure IWC-2520-1 for head circumferential welds. In addition, Examination Category C-H, Item C7.10 requires a system leakage test in I accordance with IWC-5221 for pressure vessel pressure retaining components.
Subarticle IWC-2200, "Preservice Examination," states that:
- a. All examinations required by this Article for those components initially selected for examination in accordance with Inspection Program A or Inspection Program B and not exempted by IWC-1220 shall be completed prior to initial plant startup.
- b. Shop and field examinations may serve in lieu of on-site preservice examinations, provided:
1). in the case of vessels only, the hydrostatic test required by Section III has been completed; 2). such examinations are conducted under conditions and with equipment and techniques equivalent to those expected to be employed for subsequent inservice examinations; s
3), the shop and field examination records are or can be documented and identified in a form consistent with those required by IWA-6000. ,
Mandatory Appendix III, Article III - 4000 requires examination for:
- a. Reflectors parallel to the weld seam.
The angle beam examination for reflectors parallel to the weld seam shall be performed by a full V path from one side or a one-half V path from two sides of the weld, where practicable.
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4 .
o NR-15 Rev. 1
- b. Reflectors transverse to the weld seam.
1). The angle beam examination for reflectors transverse to the weld seam shall be performed on the weld crown on a single seam path to examine the weld root by one-half V path in two directions along the weld.
2). For inservice examination, only those welds showing reportable preservice indications need be examined for transverse reflectors.
- 5. BASIS FOR RELIEF: Weld ELHXC-03 received radiographic examination to meet the requirements of ASME Section III. These examinations could be used to meet the requirements of ASME Section XI. However, we do not intend to use radiography as our inservice test method.
Ultrasonic examination of weld ELHXC-03 was limited for approximately 70%
of the weld length due to four branch connections welded to the vessel.
- 6. ALTERNATE TEST METHOD: In lieu of the required ultrasonic inspection a surface examination utilizing the liquid penetrant test will be performed on the above welds.
7.. JUSTIFICATION: The ASME Section III radiograph and hydrostatic test along with the limited ultrasonic examination and alternate surface examination will provide an, adequate level of structural integrity for plant operation.
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