ML20217P062
| ML20217P062 | |
| Person / Time | |
|---|---|
| Site: | Farley  |
| Issue date: | 03/04/1998 |
| From: | Dennis Morey SOUTHERN NUCLEAR OPERATING CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9803100005 | |
| Download: ML20217P062 (28) | |
Text
7, Dave Morey S:uther2 Nucl:ar t.
%ce Pre 9 dent Op: rating Comp =y Iarley Project P.O. Box 12!6 Birmingham. Alabama 35201 Tel 205.992.5131 March 4, 1998 SOUTHERN L COMPANY Energy ro Serve YourWorld" Docket No. 50-348 10CFR 50.55 U. S. Nuclear Regulatory Commission ATfN: Document Control Desk Washington, DC 20555 Joseph M. Farley - Unit i Second Ten-Year Interval ASME Section XI Relief Reauests Ladies and Gentlemen:
In accordance with the provisions of 10CFR50.55a, Southem Nuclear Operating Company (SNC) is requesting relief from the exammation coverage requirements of the 1983 Edition of Section XI with Addenda through Summer 1983. Approvalis requested by August 7,1998 to support second interval inservice inspection activities to be performed during the Unit I refueling outage, currently scheduled to commence in October 1998. A brief description of these second interval relief requests is attached along with the actual relief requests.
Should you have any questions or concerns regarding this matter, please contact this office.
Respectfully submitted,
(/ y 31/w Dave Morey MB:maf reliefl. doc Enclosures cc:
Mr. L. A. Reyes, Region II Administrator Mr. J. I. Zimmerman, NRR Project Manager Mr. T. M. Ross, Plant Sr. Resident inspector
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l 9803100005 980304 PDR ADOCK 05000348 P
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2, ENCLOSUREI Summany By Relief Request 1
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Summary By Relief Request l
RR-13 Reliefis requested from meeting Code specified coverage requirements for examinations performed on Main Loop Piping Branch Connection Welds. This is a revision to an existing relief request that was previously approved by the NRC to provide updated coverage determined after the completion of the
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main loop piping branch connection examinations.
RR-48 Reliefis requested to delete remaining second interval Regenerative Heat Exchanger exammations.
SNC proposes the deletion of the remaining second interval examination based on changes to later editions of the Section XI Code. This is a new relief request.
I RR-49 Reliefis requested from meeting Code specified coverage requirements for examinations performed on RPV Nozzle-to-Vessel Welds. This is a new relief request.
RR-50 Reliefis requested for meeting Code specified coverage requirements for examinations performed on the RPV Shell-to-Flange Weld. This is a new relief request.
RR-51 Reliefis requested to perform the Class I hydrostatic test with the small diameter drain lines isolated.
This is a new relief request.
RR-52 Reliefis requested from meeting Code specified coverage requirements for examinations performed on the Volume Control Tank. This is a new relief request.
RR-53 Reliefis requested from meeting Code specified coverage requirements for examinations performed on the Excess Letdown Heat Exchanger. This is a new relief request.
l RR-54 Reliefis requested from meeting Code specified coverage requirements for examinations performed on the Residual Heat Removal Heat Exchanger. This is a new relief request.
RR-55 Reliefis requested from meeting Code specified coverage requirements for examinations performed on the RPV Closure Head Nuts. This is a new relief request.
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L ENCLOSUREII Relief Requests
E FNP-1-M-043 SOUTHERN NUCLEAR OPERATING COMPANY FARLEY UNIT I SECOND 10-YEAR INTERVAL REQUEST FOR RELIEF NO. RR-13 1.
System /Comoonent for Which Relief was Reauested: Pressure retaining branch connections located on centrifugally cast stainless stect, Class 1, main loop piping. Specifically these welds are:
ALA1-4100-20BC - Cold Leg loop #1,6" Safety Injection Line Branch Connection ALA1-4100-22BC - Cold Leg loop #1,12" Accumulator Discharge Line Branch Connection ALAl-4200-15BC - Hot Leg Loop #2,14" Pressurizer Surge Line Branch Connection ALAl-4300-16BC - Hot leg loop #3,12"RHR Line Branch Connection II.
Code ReaWitemenJ: Examinatim Requirement -Item No. B9.31, Category B-J, Table IWB-2500-1 of the 1983 Edition of ASME Section XI with Addenda through Summer 1983, required volumetric (and surface) exanunation of branch pipe connection welds 4 inches nommal pipe size and larger Applicable examination volumes were defmed by Figures IWB-2500-9 and -1 I and included 100 percent of the weld length. Appendix 111-4420 required that when scanning for reflectors oriented parallel to the weld seam, that coverage of the examination volume be obtained from two beam path directions. The exam was required to be performed from two sides of the weld, when practical, or from one side, as a minimum. Appendix Ill-4430(a) required that when scanning for reflectors oriented transverse (perpendicular) to the weld seam, the examinations be performed on the weld crown such that the weld root was examined by one-half V path in two directions along the weld.
Ill.
Code Reauirement for Which Relief was Reauested: Reliefis requested from meeting the required coverage for the subject welds.
IV.
his for RSjkf: Composite coverage in this relief request was calculated by Southern Nuclea:
Operat ng Company (SNC) using the average coverage of four scans: (1) pipe side coverage for i
reflec. ors oriented parallel to the weld seam, (2) branch connection side coverage for reflectors oriented parallel to the weld seam, (3) clockwise coverage on the weld crown for reflectors oriented transverse to the weld seam, and (4) counter-clockwise ceverage on the weld crown for reflectors oriented transverse to the weld seam.
Welds 4100-20BC,4200-15BC, and 4300-16BC have configurations such that 2.4" to 3.9" thick stainless steel branch connections are " set-in" to the centrifugally cast stainless steel main loop piping and then welded. (See " set in" sketch on Attachment 13-1). Coverage obtained during second interval examination of these welds is described below.
I Pipe Side Coveragefor Parallel Reflectors - Due to the severe attenuation properties of the cast stainless steel material used in the main loop piping, meaningful data from the main run of pipe was only obtainable utilizing a 1/2 node examination,45' refracted longitudinal (RL) wave technique.
Coverage was determined to be 80% of the weld volume from the pipe side (one beam direction).
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- 2. Branch Connection Coveragefor Parallel reflectors - Scans were not performed from the branch connection side due to very limited coverage; therefore, coverage was 0%. The basis for this determination is detailed below.
Scanning from the branch connection side would have required bouncing a shear wave through metal paths (from the transducer to the examination volume) of 7" to 11" of stainless steel which would have significantly attenuated the ultrasonic energy reaching the branch connection / weld interface. Significant attenuation would have then been obtained at the weld interface and the shear wave would not have effectively penetrated into the cast stainless material. (See Attachments 13-2 and 13-3). Additional composite coverage would have been 4% to 7% if the maning had been performed.
Obtaining this minimal coverage would require fabrication of three new F-304 stainless steel calibration blocks of non-standard diameter and thickness (approximately 10.1" OD by 2.4" thick, 17.6" OD by 3.6" thick, and 19.4" OD by 3.9" thick).
- 3. Clockwise Coverage on Weld Crownfor Transverse Reflectors - Scanning clockwise on the weld crown for transverse reflectors in the weld root provided little, if any, meaningful coverage due to the curvature of the weld. While scanning was performed on the weld crown during the second interval, coverage plots indicated that the root of the weld was not effectively reached and coverage was determined to be 0%. (See Attachments 13-2 and 13-3).
4.
Counter-Clockwise Coverage on Weld Crownfor Transverse Reflectors - Scanning counter-clockwise on the weld crown for transverse reflectors in the, veld root provided little, if any, meaningful coverage due to the curvature of the weld. While scanning was performed on the weld crown during the second interval, coverage plots indicated that the root of the weld was not effectively reached and coverage was determined to be 0%. (See Attachments 13-2 and 13-3).
- 5. Composite Coverage - Using the muinod described above, the second interval composite coverage was calculated to be 20%. SNC concludes that second interval examinations for this configuration j
were performed to the maximum extent practical. Performance of additional exanunations (from j
the branch connection side) of very limited coverage, reduced effectiveness, and with the necessity i
of fabricating non-standard calibration blocks is considered to be a burden, with little compensatmg increase in the level of safety or quality.
Weld ALAl-4100-22BC has a configuration such that the SA-351, CF8A cast stainless steel "sweepolet" was welded into the cast stainless steel piping. (See "sweepolet" sketch on Attachment 13-1). Coverage is described below.
- l. Pipe Side Coveragefor Parallel Reflectors - 100% of the weld volume was examined from the pipe side using the 1/2 node,45' refracted longitudinal (RL) wave technique described above (one beam direction).
- 2. Branch Connectwn Side Coveragefor Parallel Reflectors - Coverage from the branch connection side (second beam direction) was 50% Limitations were due to the combination of cast material and curved configuration.
Ell 2
2 FNP-1-M-043
- 3. Clockwise Coverage on Weld Crownfor Transverse Reflectors - Approximately 100% of the required code coverage was obtained for this weld configuration.
4.
Counter-Clockwise Coverage on Weld Crownfor Transverse Reflectors - Approximately 100% ot the required code coverage was obtained for this weld configuration.
- 5. Compos /te coverage - Composite coverage for the second interval was calculated to be 87.5%
SNC concludes that second interval examinations for this configuration were performed to the maximum extent practical.
V.
Alternate Examination: None. Code required ultrasonic examinations were performed to the extent practical.
VI.
Justification for Grantimt Relief: The geometric configuration of the branch connections prevented ultrasonic or radiographic exanunation of the welds to the extent nx[uired. Primary cracking mechanisms for these welds is considered by the nuclear industry to be stress-corrosion cracking, thermal fatigue cracking, or mechanically induced fatigue cracking. Each is discussed below.
Stress Corrosion Cracking - In a low oxygen, PWR primary system water environment there has never been any evidence of stress <orrosion cracking in 304 stainless steel.
Thermal Fatigue Crackmg - Thermal fatigue cracking previously occurred in an FNP primary system branch line; with the cracking initiated by thermal stresses related to stratification. His crackmg was located away from the subject branch connection welds. With the subject welds located on the main mn of piping, there should be sufTicient turbulence and mixing present such that thermal stresses sufficient to initiate crackmg in the subject welds would not be present.
Mechanically Induced Fatigue Cracking - Fatigue cracking initiated by rnechanical means such as vibration was accounted for in the design of the branch connections. However, in the event that unusual sibration remained undetected and subsequently produced crackmg, the cracking would most likely have initiated on the outside of the weld and been detected with the required surface examination.
Overall the potential for cracking in these brarich connection welds is low. He low potential for cracking in these welds in conjunction with the partial volumetric exanunation and complete surface exanunation performed during the second interval should provide reasonable assurance of the continued structural integrity of these welds. Compliance with Code coverage requirements would require th.u the branch connection configurations and portions of the main loop piping be redesigned, fabricated, and installed which would be extremely expensive. Denial of this relief request would cause an excessive burden upon Southern Nuclear Operating Company because refabrication of the branch connections to perform the Code required examinations is impractical.; therefore, approval of this relief request should be granted pursuant to 10 CFR 50.55a(g)(6)(i).
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i FNP-1-M-043 Vll.
- Imolementation Schedule: This relief request is applicable for the close-out of the second interval.
Vill.
Relief Reauest Status: RR-13 was previously approved by the NRC for the second interval per SER dated August 28,1991. This revision updates previously reported coverage.
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FNP-1-M-043 SOUTliERN NUCLEAR OPERATING COMPANY FARLEY UNIT 1 SECOND 10-YEAR INTERVAL REQUEST FOR RELIEF NO. RR-48 1.
System / Component for Which Reliefis Requested: Regenerative Heat Exchanger welds and componer*,
supports.
11.
Code Reauirement: IWC-1220(c) of the 1983 Edition of Section XI with Addenda threugh Summer 1983 exempted " component connections (including nozzles in vessels and pumps), piping and associated valves, and vessels and their attachments that are 4 in. nominal pipe size and smaller" from volumetric and surface examination requirements ofIWC-2500. Applying this exemption, the small diameter Regenerative Heat Exchanger inlet and outlet piping were exempt from the volumetric and surface examination requirements oflWC-2500, but the heat exchanger was not, since it is larger than 4" nominal pipe size.
111.
Code Requngment for Which ReliefiLR_gquested: Reliefis requested to apply the exemption criteria found in the 1989 Addenda of ASME Section XI (and subsequent editions / addenda) to exempt the remaming second interval Regenerative lleat Exchanger weld from the examination requirements of l
IWC-2500. Specifically one Category C-A, item No. Cl.30 Regenerative Heat Exchanger weld will be exempted from second interval (third period) volumetric examination requirements. Additionally, two Category F-B, item No. F2.10 Regenerative 11 eat Exchanger component supports will no longer r: quire examination since the component welds are exempt.
IV.
Ilasis for Relief: Exemption criteria have been added to the 1989 Addenda of ASME Section XI (and subsequent editions / addenda) to allow the exemption of vesr,els, pumps, valves, and their connections in piping NPS 4 and smaller (excluding high pressure safety injection). The December 3,1997 amendment to 10CFR50.55a proposed the adoption of the 1995 Edition of ASME Section XI with Addenda through 1996 (which contains this exemption criteria). Additionally, this exemptian criteria is contained in Code Case N-408-2, Alternative Rulesfor Examination ofClass 2 Pipmg, which has received NRC approval for use in Regulatory Guide 1.147. Therefore, the NRC has specifically recognized the use of this exemption crite ia.
The intent of the change to the exemption criteria is to allow exemption of a component cormected to exempt piping, provided that failure of he component would not produce a leak greater than the flow through the exempt piping. For the Regenerative Heat Exchanger the inlet a:id outlet piping for the shell j
side is 3" NPS. Therefore, a crack or defect in the Regenerative Heat Exchanger shcIl would not produce a leak greater than would be produced by the loss ofinlet or outlet piping. Similarly, a crack or defect m the Regenerative Heat Exchanger tubing (which has no volumetric or surface examination requirements due to the size of the individual tubes) would not produce a leak greater than would be produced by the loss ofinlet or outlet piping. To produce a leak greater than that produced by the loss I
of a 4" NPS line would require failure of the shell and failure of multiple heat exchanger tubes, which is not considered a credible insenice failure. Therefore, the intent of the exemption is maintained.
Additionally, use of this exemption would eliminate unnecessary e..aminations located in high dose rate atcas. Previous dose rate surveys for the Unit i Regenerative Heat Exchanger examinations ir.dicate a contact dose rate of approximately 2800 mrem /hr.
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V.
Alternate Examination: The exempion criteria of the 1989 Addenda will be used.
VI.
Justification for Granting Relief: Use of the later Code edition / addenda exemption criteria to exempt the above specified components should have no adverse afrects on the existing level of safety and quality, and relief should be granted pursuant to the requirements of 10CFR50.55a(a)(3)(i). Denial of this relief request would require continued personnel radiation exposures to perform exammations not deemed necessary by later Code editions or by the NRC through approval of Code Case N-408-2.
VII.
Imolementation Schedtile: This relief request is applicable for the close-out of the second interval.
Vill.
Relief Reauest Status: 'Ihis is a new second interval relief request, awaiting NRC approval.
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FNP-1-M-043 SOUTHERN NUCLEAR OPERATING COMPANY FARLEY UNIT 1 SECOND 10-YEAR INTERVAL REQUEST FOR RELIEF NO. RR-49 1.
System / Component for Which Reliefis Requested: Reactor pressure vessel (RPV) nozzle-to-vessel welds.
Specifically these welds are identified as follows:
Outlet Nozzles Inlet Nozzles ALAl - 1100 - 17 ALAl - 1100 - 1b ALAl - 1100 - 19 ALAl - 1100 - 20 ALAl - 1100 - 21 ALAl - 1100 - 22
- 11. Code Requirement: Item No. B3.90, Category B-D, Table IWB-2500-1 of the 1983 Edition of Section XI with Addenda through Summer 1983 required a volumetric examination of each RPV nozzle-to-vessel weld.
Paragraph IWA-2232(a) of Section XI required that ultrasonic examination of vessel welds greater than 2 inches in thickness be conducted in accordance with the ASME Code,Section V, Article 4 which required two-directional coverage wherever feasible. The 1983 Edition of ASME Section V with Addenda through Summer 1983, Subarticle T-441 described the ultrasonic examination requirements for vessel welds.
Typically, vessel welds are exammed with a combination of 0,45, and 60-degree beams to meet the examination volume requirements; however, due to the special configurations involved in examining the nozzle-to-vessel welds from the nozzle bore, T-441.4.2 permitted the use of other examination angles.
Additional requirements were:
Reflectors Parallel to the Nozzle-To-Vessel Weld - T-441.5.1 required that search units be directed perpendicular to the weld so that the angle beams passed through the entire volume of the weld metal.
The adjacent base metal was required to be completely scanned; however, it was not necessary to scan from both directions.
Reflectors Transverse to the Nozzle-To-Vessel Weld - T-441.5.2 required that search units be directed parallel to the axis of the weld such that the angle beams passed through all of the examination volume.
Scanning was required to be done in two directions,180-degrees to each other, except that, for those areas blocked by geometric conditions scanning was required in at least one direction.
Ill.
Ccde Requirement for Which Reliefis Requested: Reliefis requested from meeting the required coverage for the subject welds.
IV.
Basis for Relief: Examination cowrage and the basis for limitations for each type of nozzle are listed below:
Inlet Nozzles 'Ihe required examination volume and associated weld confwuration for the inlet nozzles is shown m Section XI, Figure IWB-2500-7(a), except that the inner radius is a oth contour, not a protrusion as shown in the figure. Covemge and limitations for this configur. m are:
1.
Repectors Parallel to the Inlet No::le-To-l'essel Weld - Ultrasonic examinations were performed from the nozzle bore using 0-degree,10-degree longitudinal,30-degree longitudinal, and 50-degree longitudinal.
1, as allowed by T-441.4.2. Coverage from this ditection was 99%.
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FNP-1-M-043
- 2. Reflectors Transverse to the Inlet Nozzle-To-Vessel Weld-Ultrasonic exammations were performed on the ID of the vessel wall and accessible portions of the adjoining nozzle using 0, 45,and 60, degree angle beam scans, directed clockwise and counterclockwise.
Scanmng could not be performed a the curved portion of the nozzle inner radius. Coverage from this direction was 70% (Note A supplemental 70-degree angle beam scan was used to investigate the ID surface as requiret by Regulatory Guide 1.150, Revision 1).
3.
Composite Cowrage - Composite coverage was calculated as 84.5% based on the average of the two coverages listed above.
Outlet Neules - The required exanunation volume and associated weld configuration (barrel type nozzle with a protmding inner radius) for the outlet nozzles is shown in Section XI, Figure IWB-2500-7(a). Coverage and limitations for this configuration are listed below.
- l. Reflectors Parallel to the Outlet Nozzle-To-Vessel Weld - Ultrasonic examinations were performed from the nozzle bore using 0-degree,10-degree longitudinal,30-degree longitudinal, and 50-degree longitudinal scans, as allowed by T-441.4.2. Coverage from this direction was 100%.
2.
Reflectors Transverse to the Outlet Nozzle-To-Vessel Weld - Ultrasonic examinations were performed on the ID of the vessel wall using 0,45,and 60, degree angle beam scans, directed clockwise and counterclockwise. 'Ihe protruding inner radius prevented scanmng on the nozzle. Coverage from this direction was 53% (Note: A supplemental 70-degree angle beam scan was used to investigate the ID surface as required by Regulatory Guide 1.150, Resision 1).
3.
Composite Cowrage - Composite coverage was calculated as 76.5% ba:;ed on the average of the tu coverages listalabove.
V.
Alternate Exammation: Ultrasonic examination of these welds was performed to the maximum extent practical from the nozzle bore and from the RPV ID surface. No other examination will be conducted.
VI.
Justification for Grantina Relief: Various techniques were evaluated including the use of additional angles; however, it was concluded that the techniques described above permitted the maximum practical coverage to be obtained. Compliance with Code coverage requirements would necessitate refabrication of the RPV nozzles, which would be extremely expensive. The examinations performed during the second interval provided reasonable assurance that inservice flaws exceeding acceptance standards have not developed in the subject welds. Denial of this relief request would cause an excessive burden upon j
Southem Nuclear Operating Company because refabrication of the nozzles to perform the Code l
required examinations is impractical; therefore, approval of this relief request should be granted pursuant l
I Vll.
Implementalien Schedule: This relief request is applicable for the close-out of the second interval.
Vill.
Relief Request Status: This is a new relief request awaiting NRC approval.
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FNP-1-M-043 SOUTHERN NUCLEAR OPERATING COMPANY FARLEY UNIT 1 SECOND 10-YEAR INTERVAL REQUEST FOR RELIEF NO. RR-50 1.
System / Component for Whic'n Reliefis Reauested: Reactor Pressure Vessel (RPV) Shell-to-Flange
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weld. Specifically this weld is identified as follows:
J ALAl - 1100 - 1 II.
Code Reauirement: Item No. Bl.30, Category B-A, Table IWB-2500-1 of the 1983 Edition of Section XI with Addenda through Summer 1983 required a volumetric examination ofessentially 100% of the length of the reactor pressure vessel (RPV) shell-to-flange weld. The applicable exanunation volume is shown in Figure IWB-2500-4. Paragraph IWA-2232(a) of Section XI required that ultrasonic exanunation of vessel welds greater than 2 inches in thickness be conducted in accordance with ASME Code,Section V, Article 4 which required two-directional coverage wherever feasible. The 1983 Edition of ASME Section V with Addenda through Summer 1983, Subarticle T-441.4 described the scanning requirements for vessel welds. Typically, vessel welds are examined with a combination of 0,45, and 60-degree beams to meet the exammation volume requirements; however, due to the special configurations involved in examining the shell-to-flange weld, T-441.4.2 permitted the use of other examination angles.
Reflectors Parallel to the Shell-to-Flange Weld - T-441.5.1 required the search units be directed perpendicular to the weld so that the angle beams pass through the entire volume of the weld metal. The adjacent base metal was required to be completely scanned also; however, it is was not necessary to scan from both directions. In addition, T-441.5.1 allowed that when ultrasonics (UT) exanunations v'ere performed from the flange face, complete coverage of the weld from one direction was acceptable.
Reficctors Transverse to the Shell-to-Flange Weld - T-441.5.2 required the search units be directed parallel to the axis of the weld such that the angle beams pass through all of the exa.mination volume.
Scanning was required to be done in both directions,180-degrees to each other. In addition, T-441.5.2 called out that areas limited due to configuration were required to be examined from one direction. r.1 a minimum.
111.
Code Requirement for Which Reliefis Reauested: Reliefis requested from meeting the required coverage for the subject weld.
IV.
Basis for Relief: Exanunation covemge and the basis for the limitations are listed below. (Attachment 50-1 shows the Farley shell-to-flange configuration).
1, Reflectors Parallel to the Shell-to-Flange Weld-As allowed by T-441.4.2, ultrasonic exanunations were performed from the flange seal surface with the sound beam stnkmg the exanunation vohune at near-normal incidence to the weld fusion line using 0,6,12, and 16-degree beants. Essentially 100%
cowrage was obtaincd during these exanunations; therefore, Code requirements for reflectors oriented parallel to the weld were met as allowed by T-441.5.1. (Note: Automated 45-and 60-degree examinations were attempted from the RPV ID during the conduct of the ten-year RPV exanunations as part of standard Westinghouse practices; however, interference between the sled holding the transducers and the sharp ID taper prevented meaningfid exanunations. Supplemental 70-degree exanunations for Ell-12
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FNP-1-M443 Regulatog Guide 1.150, Revision 1 issues were also performed, during the ten-> car exammations, to the extent pmetical.).
- 2. Reflectors Transverse to the Shell-to-Flange Weld-Standard Westinghouse automated examinations using a s!cd in contact with the RPV ID were performed on this weld from the using 45-and 60-degree transducers oriented to detect indications transverse to the weld; however, interference between the sled holding the transducers and the sharp ID taper limited the examuntions. He exammations were performed in both the clockwise and counter-clockwise directions with the lower 30%
of the examination volume being scanned. A supplemental 70-degree beam was used to investigate the ID surface as required by Regulatory Guide 1.150, Revision I with a coverage equal to 47% of the examination volume.
Discussions with Westmghouse exanunation personnel indicated that the flange configumtion at Farley has a severe taper when compared to many other reactor pressure vessels they examine; therefore, the limited coverage was appropriate for the W.stmghouse standard exanunations that were performed.
Reviews indicate that 45-and 60-degree coverage for reflectors transverse to the wc!d could theoretically have been increased (from 30% to approximately 47%) by removing the exanunation slai from the RPV and manually repositioning individual traducers; however, this was not a standard practice performed during the conduct of RPV exanunations.
3.
Composite Cowrage - Based on the average of the two scans listed above, composite coverage was calculated as 65%.
V.
Alternate Examination: The supplemental 70-degree beam used to investigate the ID surface prosided increased coverage for reflectors oriented perpendicular to the weld. No additional exanunations are planned for the second interval; however, for the third interval Southem Nuclear Operating Company will work with the NDE vendor to evaluate techniques and equipment such that optimized coverage of this weld is obtained, to the extent practical.
VI.
Justification for Granting Relief: Examinations conducted during the first interval were performed using a combination of manual examinations from the flange surface and automated " immersion" technique examinations from the RPV ID. During the " immersion" technique examinations, the physical flange geometry had much less effect on coverage than it did with the " contact" technique currently used by NDE vendors, since with an " immersion" technique the trasducers are not in contact with the ID surface. Since NDE vendors have changed to contact techniqua, total compliance with second interval Code requirements would necessitate either refabrication of the FPV flange or for the NDE vendors to change equipment and techniques. Refabrication of the RPV to Mstall a new 11ange or requiring an NDE vendor to obtain/ develop specialized automated inspection equipment for Farley would be very expensive.
Examinations performed during the first interval on this weld gave reasonable assurance that neither circumferentially oriented or axially oriented flaws excceding acceptance standards were present. For the second interval, Code examination of the weld from the flange surface provided coatinued assurance that circumferential cracking exceeding acceptance standards have not developed. From a technical standpoint, circumferential cracking is considered to be the more limiting case with sersice-induced axially oriented cracking considered a very unlikely scenario for this weld. Herefore, while not meeting the specified Code coverage requirements (for axially oriented flaws), the Code examination performed 1
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from the flange surface in conjunction with the limited automated 45,60, and 70-degree examinations
' provided reasonable assurance that the structural integrity of the weld is being maintamed Denial of this relief request would cause an excessive burden upon Southern Nuclear Operating Company because refabrication of the RPV flange to perform the Code required exanunations is impractical; therefore, approval of this relief request should be granted pursuant to 10 CFR 50.55a(g)(6)(i).
VII.
Imolementation Schedule: 'lhis relief request is applicable for the close-out of the second interval.
Vill.
Relief Reauest Status: This is a new relief request awaiting NRC approval.
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SOUTiiERN NUCLEAR OPERATING COMPANY j
FARLEY UNIT 1 i
SECOND 10-YEAR INTERVAL REQUEST FOR RELIEF NO. RR-51 I.
System / Component for Which Reliefis Requested: Approximately 40, small diameter (s 1 inch), Class 1, reactor coolant system (RCS) pressure boundary vent and drain connections.
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II.
Code Reauirement: The 1983 Edition of ASME Section XI with Addenda through Summer 1983, Table IWB-2500-1, Examination Category B-P, item Numbers B15.51 and B15.71 requires the system hydrostatic test to include all Class I components within the system boundary.
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i III.
Code Reauirement for Which Reliefis Requested: Reliefis requested to perform the Class 1 System f
flydrostatic Test with the vent and drain valves in the closed position.
l IV. Basis For Relief: Rese connections are equipped with manual valves which provide for double isolation of the reactor coolant system (RCS) pressure boundary. These valves are generally maintained closed during all modes of operation and the piping outboard of the first isolation valve is, therefore, not I
normally pressurized. The proposed attemative provides an acceptable level of safety and quality based on the following:
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1.
ASME Section XI Code, paragraph IWA-4400, provides the requirements for hydrostatic pressure testing of piping and components after repairs by welding to the pressure boundary. IWA-4400(b)(5) exclude; component connections, piping, and associated valves that are 1 inch norninal pipe size and smaller from the hydrostatic pressure test requirement after welded repairs. Therefore, requiring a hydrostatic test and visual examination of these s 1 inch diameter RCS vent / drain connections once each 10-year interval is unwarranted considering that a repair weld on the same connections is exempted by the ASME XI Code.
- 2. The non-isolable portion of the RCS vent and drain connections will be pressurized and visually examined as required. Only the isolable portion of th vent and drain connections is not pressurized.
- 3. A typical vent / drain connection includes two manual valves separated by a short pipe nipple which is connected to the RCS via another short pipe nipple and a half coupling. AP connections are typically socket-welded and the welds received a surface examination after installation. The piping and valves are nominally heavy wall (Sch.160 pipe and 6000# valve bodies). He vents and drains are not subjected to high stresses or cyclic loads, and the design ratings are significantly greater than RCS operating or design pressure.
4.
He Technical Specifications (TS) require RCS leakage monitoring during normal operation. Should any of the TS limits be exceeded, then appropriate corrective actions, which may include shutting the plant down, are required to identify the source of the leakage and restore the RCS boundary integrity.
Ell-16 i
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FNP-1-M-043 Additionally, SNC believes that there are also potential personnel safety and ALARA issues associated i
with pressurizing these connections. Rese issues are as follows:
- 1. ASME Code Case N-498-1 is currently used at FNP to perform this test. Pressure testing these connections to the outboard valve requires the inboard isolation valves to be opened and subjects the valves and piping to RCS nominal operating pressure and near operating temperature. Opening the inboard valve at these conditions is contradictory to the requirement for double isolation of the RCS and thus creates the possibility for safety concerns for personnel performing visual examination of the connections.
2.
Performing the test with the inboard valves open requires several man-hours to position the valves for the test and then to restore them after the test is complete. All of these valves are located in close proximity of the RCS main loop piping thus requiring personnel entry into high radiation areas within the containment. Based on previous outage data it is estimated that dose associated with valve alignment and realignment would be approximately 1.2 man-Rem per test.
3.
Since this test would be performed near the end of an outage, when all RCS work has been j
completed, the time required to open and then close these vent / drain valves could impact the outage schedule.
V.
Alternate Examinations: The RCS vent and drain connections will be visually examined with the isolation valves in the normally closed position each refueling outage for leakage and evidence of past leakage during the ASME XI Class 1 System Leakage Test (IWB-5221).
ne RCS vent and drain connections will also be visually examined with the isolation valves in the normally closed position during the 10-year ISI pressure test (IWB-5222 and Code Case N-498-1). This examination will be performed with the RCS at nominal operating pressure and at near operating temperature after satisfying the required 4-hour hold time.
VI. Justification for Grantina Relief: Requiring a hydrostatic test and visual examination of these 5; 1 inch diameter RCS vent / drain connections once each 10-year interval is unwarranted considering that a repair weld on the same connections is exempted by the ASME XI Code. The added radiation exposure and potential for outage impact associated with opening the valves is not considered justifiable, since the proposed alternative visual examinations (in conjunction with the TS monitoring requirements for RCS l
leakage) should provide assurance that the RCS pressure boundary, associated with these connections, is being maintained at an acceptable level of quality and safety. Denial of this relief request results in the potential for oatage schedule impacts and radiation exposure without a compensating increase in the level of quality and safety; therefore, the proposed alternative should be granted pursuant to the requirements of 10CP"50.55a(a)(3)(ii).
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I VII.
Implementation Schdyle: This relief request is applicable for the close-out of the second interval.
bil.
Rslief RcqugitSta_tgr his is a new zecond interval relief request, awaiting NRC approval.
l Ell-17 l
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FNP-1-M-043 SOUfHERN NUCLEAR OPERATING COMPANY FARLEY UNIT 1 SECOND 10-YEAR INTERVAL REQUEST FOR RELIEF NO. RR-52 1.
System / Component for Which Relief was Requested: Chemical and Volume Control System - Volume Control Tank Weld No. 2 (bottom head-to-shell).
II.
Code Reauirement: Exammation Requirement -Item No. Cl.20, Category C-A, Table IWC-2500-1 of the 1983 Edition of ASME Section XI with Addenda through Summer 1983, required volumetric exammation of essentially 100% of the length of the weld.
III.
Code Reauirement for Which Relief was Reauested: Reliefis requested from meetmg the required coverage for the subject weld.
IV.
Basis for Relief: The design of this tank (see Attachment 52-1) includes four legs welded near the subject weld which prevented complete ultrasonic or radiographic examination of the weld. Coverage was calculated to be 80%
V.
Alternate Examination: None. Code required altrasonic examinations were performed to the extent practical.
VI.
Justification for Grantian Relief The interference resulting from the presence of the four legs prevented ultrasonic or radiographic examination of the weld to the extent rquired. In order to have exanuned the weld in accordance with the requirements, the tank would have had to been rWgned fabricated, and installed which would be expensive. The examinations performed during the second interval provided reasonable assurance that inservice flaws exceeding acceptance standards have not developed in the subject welds.
Denial of this relief request would cause an excessive burden upon Southern Nuclear Operating Company (SNC) because refabrication of the tank to perform the Code required examinations is impractical; therefore, approval of this relief request should be granted pursuant to 10 CFR 50.55a(g)(6)(i).
It should be noted that for the third interval, SNC has requested relief from examination of this component. (See RR-14 in the SNC submittal dated May 28,1997). This reliefis based on the fact that exemption criteria have been added to the 1989 Addenda of ASME Section XI (and subsequent editions / addenda) that allows the exemption of vessels, pumps, valves, and their connections in piping NPS 4 and smaller (excluding high pressure safety injection).
VII.
ImpJr.tnentation Schedulg; This relief request is applicable for the close-out of the second intenal.
Vill.
Eclief Request Slatyr This is a new second interval relief request.
Ell 18
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Ell-19
FNP-1-M-043 SOUEERN NUCLEAR OPERATING COMPANY FARLEY UNIT 1 SECOND 10-YEAR INTERVAL l
REQUEST FOR RELIEF NO. RR-53 1.
System /Comnonent for Which Reliefis R~m-*~I: Chemical Volume Control System Excess Letdown Heat Ev4===cr Weld No.1 (head-to-weld neck flange).
II.
Code Reauirement: Evaminatina Reqmrement - Itan No. C1.20, Category C-A, Table IWC-2500-1 of the 1983 Edstion ofASME Section XI with Addenda through Summer 1283, required volametre exammation of
~a=*ially 100% of the length of the weld.
111.
Code Reauirement for Which Reliefis Reauested: Reliefis requested from meeting the required coverage for the subject weld.
IV.
Basis for Relief: The taper on the weld neck Gange severely limited the conduct of ultrasonic examinations from the flange side. Ultrasonic exammations from the head were limited by the presence of the inlet nozzle, the outlet nozzle, and two vent / drain lines. Ultrasonic exammation coverage w3s calculated to be 49%. Performance of radiographic examinations was not feasible due to presence of the head divider plate. (See Attachment 53-1).
V.
Alternate Examination: None. Code required ultrasonic examinations were performed to the extent practical.
VI.
Justification for Grantina Religf: The geometric configuration prevented ultrasonic exammation of the weld to the extent required. In order to have exanuned the weld in accordance with the requirements, the heat exchanger would have had to been redesigned, fabiicated, and installed which would be expansive. 'Ihe examinations performed during the second interval provided reasonable assurance that inservice flaws exceeding acceptance standards have not developed in the subject welds. Denial of this relief request would cause an excessive burden upon Southern Nuclear Operating Company (SNC) because refabrication of the heat exchanger to perform the Code required examinations is impractical; therefore, approval of this relief request should be granted pursuant to 10 CFR 50.55a(g)(6)(i).
It should be noted that for the third interval, SNC has requested relief from examination of this component. (See RR-14 in the SNC submittal dated May 28,1997). This reliefis based on the fact that exemption criteria have been added to the 1989 Addenda of ASME Section XI (and subsequent j
editions / addenda) that allows the exemption of vessels, pumps, valves, and their connections in piping NPS 4 and smaller (excluding high pressure safety injection).
Vll.
Implementation Schedulg: This relief request is applicable for the close-out of the second interval.
Vill.
Relief Reauest Status: This is a new second interval relief request.
Ell-20
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PLATE EXCESS LETDOWN HEAT EXCHANGER ATTACHWENT 53-1 ExtETDHx Ell-21 i
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FNP-1-M-043 SOUTHERN NUCLEAR OPERATING COMPANY FARLEY UNfr 1 SECOND 10-YEAR INTERVAL REQUEST FOR RELIEF NO. RR-54 1.
System / Component for Which Reliefis Reauested: Residual Heat Removal Heat Exchanger Weld No.
1 (shell-to-weld neck flange).
II.
Code Reouirement: Examination Requirement - Item No. C1.10, Category C-A, Table IWC-2500-1 of the 1983 Edition of ASME Section XI with Addenda through Summer 1983, required volumetric examination of esscutially 100% of the length of the weld.
III.
Code Reauirement for Which Reliefis Reauested: Reliefis requested from meeting the required coverage for the subject weld.
IV.
Basis for Relief: The taper on the weld neck flange severely limited the conduct of u!trasonic examinations from the flange side. Ultrasonic examinations from the bottom head were limited by the presence of a nozzle reinforcement collar welded around the inlet and outlet nozzles. Ultrasonic exammation coverage was calculated to be 80%. Performance of radiographic exammations was not feasible due to presence of the bottom head divider plate. (See Attachment 54-1).
V.
Altemate Examination: None. Code required ultrasonic examinations were performed to the extent practical.
VI.
Justification for Grantine Relief: The geometric configumtion prevented ultrasonic exammation of the weld to the extent required. In order to have exammed the wcld in accordance with the requirements, the beat exchanger would have had to been redesigned, fabricated, and installed which would be expensive. We examinations performed during the second interval provided reasonable assurance that inservice flaws exceeding acceptance standards have not developed in the subject welds. Denial of this relief request would cause an excessive burden upon Southern Nuclear Operating Company because refabrication of the heat exchanger to perform the Code required examinations is impractical; therefore, approval of this relief request should be granted pursuant to 10 CFR 50.55a(g)(6)(i).
VII.
Implementation Schedule: This relief request is applicable for the close-out of the second interval.
Vill.
Relief Request Status: His is a new second interval relief request.
Ell-22
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FNP-1-M-043 RESIDUAL HEAT EXCHANGER
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FNP-1-M-043
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SOlJTHERN NUCLEAR OPERATING COMPANY FARLEY UNIT I SECOND 10-YEAR INTERVAL REQUEST FOR RELIEF NO. RR-55 1.
System / Component for Which Reliefis Reauested: Reactor Pressure Vessel (RPV) closure head nuts.
II.
Code Reauirer'teqt: Exammation Requirement -Item No. U6.10, Category B-G-1, Table IWB-2500-1 of the 1983 Edition of ASME Section XI with Addenda through Sumtre 1983, required surface exammation of RPV closure head nuts. Surface exanunations were required to be performed in accordance with ASME Section V,1983 Edition with Addenda through Summer 1983 with Magnetic Particle (MT) exasetions being selectal as the surface examination method. For MT examinations, Subarticle T-741 of ASME Section V,1983 Edition with Addenda through Summer 1983 required that at least two separate exammations be performed on each area subject to examination. During the second examination, the lines of magnetic flux were required to be approximately perpendicular to those used during the first examination.
111.
Code Reauirement for Which Reliefis Requested: Reliefis requested from meeting the "approximately 1
perpendicular" requirements of Subarticle T-741.
IV.
Basis for Relief: MT examination of the " exterior" surface of the closure head nuts was performed using two examinations approximately perpendicular to cach other. Coverage of the " exterior " surface was 100%. For the " interior" surface, the first examination was performed with the lines of magnetic flux normal to the threads; however, the second examination could not be performed "approximately perpendicular" to the first examination, since a MT yoke would not phy sically fit inside the nuts. (The lines of magnetic flux for the second examination were only +20 degrees to -20 degrees from those of the first examination). Coverage of the " interior" surface was, therefore,50% and composite examination coverage was calculated to be 75%.
V.
Alternate Examination: A VT-1 cxamination was performed on the interior surface of the nuts.
VI.
hstification for Grantina Relief: The 1989 Addenda and subsequent editions of ASME Section XI changed the examination requirements of RPV closure head nuts from a surface examination to a sisual examination, VT-1. The proposed December 3,1997 amendment to 10CFR50.55a issued by the NRC proposed the adoption of the 1995 Edition of ASME Section XI with Addenda through 1996. As a result, the NRC has recognized that VT-1 examinations of RPV closure head nuts provides an acceptable attemative to the 1989 Code required surface examinations. Public health and safety will not be endangered; therefore, this relief request should be granted pursuant to the requirements of 10CFR50.55a(a)(3)(i).
Vll.
Iniplementation Schedulg: This relief request is applicable for the close-out of the second interval.
Vill.
Relief Rsauest Stalur This is a new second interval relief request. It should be noted that for the third interval, SNC has requested relief to substitute a VT-1 examination for the required surface examination of this component. (See RR-13 in the Southern Nuclear Operating Company submittal dated May 28,1997).
Ell-24