NRC-99-0040, Requests NRC Approval of Revs to Weld Tables of Encl Relief Requests RR-A21,rev 1 & RR-A22,rev 1.Revs Do Not Impact Basis for Original Requests for Relief Because There Is No Change to Technical Basis or Proposed Alternative

Requests NRC Approval of Revs to Weld Tables of Encl Relief Requests RR-A21,rev 1 & RR-A22,rev 1.Revs Do Not Impact Basis for Original Requests for Relief Because There Is No Change to Technical Basis or Proposed Alternative

ML20206S789
Person / Time
Site:	Fermi
Issue date:	05/14/1999
From:	Gipson D DETROIT EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
CON-NRC-99-0040, CON-NRC-99-40 NUDOCS 9905240001
Download: ML20206S789 (12)

Text

Douglas R. Gipson Senior Vice President, Nuclear Generation Ferm12 6400 North Dixie liwy., Newport, Michigan 48166 Tel: 734.58G.5201 Fax: 734.686.4172 Detroit Edison May 14,1999 NRC-99-0040 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington D C. 20555-0001

References:

1), Fermi 2 NRC Docket No. 50-341 NRC License No. NPF-43

2) Detroit Edison Letter to the NRC,

" Relief Requests RR-A21 and RR-A22",

NRC-98-0060, dated April 16,1998 i l

3) Detroit Edison Letter to the NRC,

" Clarification of the Requirements for Alternative Visual Examination Specified in RR-A21 and RR-A22",

NRC-98-0116, dated July 27,1998

4) NRC Letter to Detroit Edison, 4

" Fermi 2 Relief Requests for the First 10 - Year IntervalInservice Inspection (ISI) Nondestructive Examination (NDE) Program",-

(TAC No. MA1570), dated August 25,1998

Subject:

Interval 1 Relief Reauest Update Followine Refuel Outace Six (RF06)

Requests for relief from the American Society of Mechanical Engineers (ASME)

Code,Section XI requirements were submitted to the NRC for the First Ten-Year  ;

Interval, Inservice Inspection (ISI) Nondestructive Examination (NDE) Program by [

Reference 2. These requests for relief were accepted as noted in Reference 4.

9905240001 990514 7 PDR ADOCK 05000341A A

di D d' g b A IYTE Energy Company

c USNRC

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NRC-99-0040 l

Page 2 l -- These relief requests identified expected coverage for some welds not yet examined.

Enclosures 1 and 2 of this letter contain revisions to the weld tables based on coverage reported during RF06.

Relief Request RR-A21 documented four lug weld sets received better than expected coverage and were deleted from Table 1. One set of Category B-K-1 attachment welds on Table 1 (SW-E21-3052-2WS-2WV) was found to be inaccessible for surface examination because of welded retainer clips and was subjected to the approved VT-1 alternative examination.

Relief Request RR-A22 documented two lug weld sets received better than expected coverage and were deleted from Table 1. One Category C-C attachment weld pad (PSFW-El1-3177-718B was found to be limited because ofits proximity to a building wall and was added to Table 1.

Detroit Edison does not believe these revisions impact the basis for the original requests for relief because there is no change to the technical basis or proposed alternative. We are requesting that you approve the table revisions. Detroit Edison will incorporate these Relief Request Revisions into the. ISI NDE Program upon NRC approval.

Should you have any questions or require additional information, please contact Mr. Norman K. Peterson of my staff at (734) 586-4258.

Sincerely, -

Enclosures l

l cc: A. J. Kugler A. Vegel NRC Resident Office l Regional Administrator, Region Ill Supervisor, Electric Operators, Michigan Public Service Commission l

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ENCLOSURE 1 TO NRC-99-0040 RELIEF REQUEST RR-A21 REVISION I /

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Enclosure 1 to NRC-99-0040 Page1 RELIEF REQUEST RR-A21 REVISION 1 COMPONENT FUNCTION / DESCRIPTION:

Piping Integral Attachment Welds (see attached Table 1 for identification)

SYSTEMS:

Main Steam (B21)

Reactor Recirculation (B31)

Residual Heat Removal (El1)

Core Spray (E21)

Feedwater (N21)

' ASME CODE CLASS:

Class 1 ASME SECTION XI REOUIREMENTS:

ASME Section XI,1980 Edition including the Winter 1981 Addenda, Subsection IWB, Table IWB-2500-1, Category B-K-1, item B10.10 requires surface examination of all integrally welded piping attachments that have a base metal design thickness of 5/8" or greater.

BASIS FOR RELIEF:

Pursuant to 10 CFR 50.55a(a)(3)(i) Detroit Edison is requesting relief from ASME Section XI requirements to perform complete (> 90% coverage) surface examination of all integrally welded piping attachments that have a base metal design thickness of 5/8" or greater.

The proposed alternative is partial nondestructive examination supplemented by visual examination. Technicaljustification for the adequacy of the alternative is substantiated by changes in the ASME Code.

The relief request also identifies burdens associated with engineering resource impacts, clamp removal and location restoration which would represent a burden to existing resources.

Identification of these burdens are provided only in support of the need for an alternative. The engineering impacts mentioned are incurred in diverting limited engineering resources away from other tasks.

n Enclosure 1 to -

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NRC-99-0040 Page 2 The structural integrity of the piping pressure boundary including welded attachments was j originally demonstrated during construction by meeting the requirements of ASME Section III. I Design, fabrication, installation, inspection, and examination satisfied the appropriate Code requirements. Construction examinations used techniques similar to those used for inservice examinations (surface NDE methods). During the Fermi Preservice Inspection volumetric -

examinations were also performed. The construction and preservice examinations were usually completed prior to installation of the support members. Therefore, the extent of accessibility was not specifically known until the first inservice examination is completed. Integral attachment locations remaining to be examined were compared to locations similar in design and any expected limitations are listed in the table. l The pressure boundary passed the required preservice hydrostatic test and all subsequent pressure tests through the fifth refueling and inspection outage (RF05).  !

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~ Complete examinations meeting the coverage requirements of ASME Code Section XI were l performed on welds of similar configurations which utilized the same weld techniques, I procedures and materials. The welds with complete examinations are spread throughout the Class I systems and subject to similar operating and environmental conditions as the partially examined welds. No service related discontinuities have been discovered on welds fully examined or those partially examined. Additionally, there is no industry history of ASME Class I service induced attachment weld failures. It is reasonable to expect that the unexamined portions are also acceptable.

The absence of significant integral attachment weld problems is further evidenced by ASME Code Case N-509 which allows a reduced sample size of only 10% of all integral attachments.

This Code Case has been approved at other nuclear facilities (e. g., Duane Arnold) and was incorporated into the 1995 Addenda of ASME Section XI. Detroit Edison has not requested to implement this Code Case, which would reduce the inspection population to approximately 10 locations, during our first inspection interval. - We are only requesting partial relief of coverage on specific locations included in the 29 locations where examinations can be performed.

The average surface coverage for the incomplete examinations completed and listed in Table 1 is approximately 68%. To obtain complete Code coverage at each location, the component support would have to be disassembled and the pipe clamp assembly removed. Temporary line support would have to be evaluated by engineering and installed as necessary. The additional engineering resources, time, field personnel, and radiation exposure required to attain full coverage is not consistent with the minimal risk associated with these items, as reflected by plant and industry experience as well as current Code requirements.

Radiation exposure for a best case location assuming a conservative effective (averaged) dose 1 rate'of Smr/hr and a minimum of 16 manhours to remove and reinstall the clamp assembly and inspect the location would result in at least 80mr additional exposure per location (approximately

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Enclosure I to NRC-99-0040 Page 3 1.7R minimum accumulated dose). Note that this assumption uses an effective averaged dose rate, and actual dose on a pipe and is often much higher. Removal of the clamps could actually increase the possibility of damaging other components such as nozzles and penetrations due to additional line stress. Additionally, the time for disassembly and reassembly does not assume mechanical difficulties such as temporary line support, seized bolts, and removal and reinstallation of welded lug retainers from the clamps, that will greatly increase the time and dose impacts.

ALTERNATIVE EXAMINATION:

Detroit Edison proposes that in addition to the surface examination of the exposed portion oflug welds and required base metal volume, that a supplemental visual examination to the extent practical by the examiner be performed. Additionally, leakage inspections were performed at the -

completion of each refueling outage per Category B-P.

1 The supplemental visual examinations for partial exams previously performed were conducted in a manner similar to ASME Section XI, VT-1. The purpose of the supplemental visual exam is to ,

additionally determine the condition of the integral attachment, weld, or required base metal  !

volume in the areas with surface examination limitations. The visual examination is performed to i

identify conditions that would indicate impaired structural integrity such as cracks, evidence of  ;

leakage, abnormal wear, corrosion / erosion, or physical damage on the accessible surfaces of the l component. The visual examinations are performed within 24 inches of the component surface.  !

Mirrors and artificial lighting are used as determined to be necessary by the examiner. Previous j examinations were performed by qualified and certified nondestructive examination personnel, knowledgeable of welding, material processing, and service induced defects, no defects were reported. This is consistent with the results of all nondestructive surface examinations completed I to date for ASME Class 1 and 2 integral attachments and the VT-3 of ASME Class 3 integral  !

attachments. All supplemental visual exams beginning at RF06 will be performed by ASME Section XI certified VT examiners. Any of the conditions listed above would be reported on the data sheet required by the surface examination procedure and as required by the Fermi corrective action program. If any of the above conditions are reported, clamp disassembly will be performed  !

. as necessary to allow performance of a full surface examination.

Based on the coverage achievable, physical limitations, comparison of Fermi ISI Program scope as compared to current Code requirements, and low empirical probability of weld failure, Detroit Edison considers the proposed alternative examination to provide an acceptable level of quality and safety.  ;

APPLICABLE TIME PERIOD:

Reliefis requested for the first 10-year inspection interval, t<

Enclosure 1 to NRC-99-0040 Page 4 RR-A21 Table 1 Limited Examinations Category Weld Percentage Limitation Alternate

/ Item Identification Complete Description Examination B-K-1/B10.10 FW-PS-2-D2- 70 % Clamp at spring B21-5355- Supplemental AA l-AA4 HDI Visual B-K-1/B 10.10 FW-RD-2-A2- 68 % Clamp at spring B31-5357- Supplemeral ALl-AL4 HA2 Visual B-K-l/B10.10 SW-RS-2-B2- 68 % Clamp at spring B31-5359- Supplemental W6A-W9A HB1 Visual B-K-l/B10.10 PSFW-El1-2298- 69% perlug Clamp at rigid support Supplemental 833A-F El 1-2298-G04 Visual B-K-1/B10.10 PSFW-El1-2299- 50% per lug Clamp at spring El1-2299- Supplemental 781A-D G01 Visual B-K-1/B 10.10 SW-E l l-2327- 90% perlug Clamp at restraint ElI- Supplemental 2WD-2WJ 2327-G03 Visual B-K-1/B 10.10 SW-E21-3052- 88% per lug Clamp at spring E21-3052- Supplemental 2WN-2WR G02 Visual B-K-1/B10.10 PSFW-E21-3052- 84% per lug Clamp at spring E21-3052- Supplemental 803A-D G04 Visual B-K-l/B 10.10 SW-E21-3053- 86% per lug Clamp at spring E21-3053- Supplemental 2WN-2WR G02 Visual j B-K-1/B 10.10 SW-E21-3052- 0% perlug Clamp at spring E21-3052- Supplemental

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2WS-2WV G09 Visual l

B-K-1/B 10.10 SW-E21 3053- 69% per lug inaccessible for MT due to Supplemental 2WS-2WV lug retainers at spring E21- Visual 3053-G10 B-K-1/B 10.10 SW-E21-3053- 88% per lug Clamp at spring E21-3053- Supplemental i 795A-795D G08 Visual )'

B-K-1/B10.10 SW-N21-2336- 86% per lug Clamp Limitation Supplemental 12WC-12WH Visual B-K-l/B10.10 SW-N21-2336- 66% perlug Clamp Limitation Supplemental 12WJ-12WP Visual B-K-l/B l 0.10 SW-N21-2336- 0% per lug inaccessible for MT due to Supplemental j 19WB-19WE lug retainers at N21-3537 Visual G29 B-K-1/B 10.10 SW N21-2336- 90% perlug Clamp at snubber Supplemental 9WB-9WE N21-3536-G29 Visual B-K-1/B 10.10 SW-N21-2336- 90% per lug Clamp at spring N21-3537 Supplemental )

2WC-2WP G26 Visual i I

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ENCLOSURE 2TO NRC-99-0040 RELIEF REQUEST l RR-A22 REVISION 1 l I

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r Enclosure 2 to NRC-99-0040 Page1 RELIEF REQUEST RR-A22 REVISION 1 COMPONENT FUNCTION / DESCRIPTION:

Piping Integral Attachment Welds (see attached Table 1 for identification)

SYSTEMS:

Residuallieat Removal (El1)

High Pressure Coolant Injection (E41)

ASME CODE CLASS:

Class 2 ASME SECTION XI REOUIREMENTS:

ASME Section XI,1980 Edition including the Winter 1981 Addenda, Subsection IWC, Table IWC-2500-1, Category C-C, items C3.10 and C3.20 require surface examination ofintegrally welded piping attachments that have a base metal design thickness of 3/4" or greater.

BASIS FOR RELIEF:

Pursuant to 10 CFR 50.55a(a)(3)(i) Detroit Edison is requesting relief from ASME Section XI requirements to perform complete (> 90% coverage) surface examination of all integrally welded piping attachments that have a base metal design thickness of 3/4" or greater.

The proposed alternative for Fermi is partial nondestructive examination supplemented by visual examination. Technicaljustification for the adequacy of the alternative is substantiated by changes in the ASME Code.

This relief request also identifies burdens associated with engineering resource impacts, clamp removal, location restoration, which would represent a burden to existing resources.

Identification of these burdens are provided only in support of the need for an alternative. The engineering impacts mentioned are incurred in diverting limited engineering resources away from other tasks.

The structural integrity of the piping pressure boundary including welded attachments was originally demonstrated during construction by meeting the requirements of ASME Section 111.

Design, fabrication, installation, inspection, and examination satisfied the appropriate Code I

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, Enclosure 2 to NRC-99-0040 Page 2 .

f requirements. Construction examinations used techniques similar to those used for inservice examinations (surface NDE methods). During the Fermi Preservice Inspection volumetric examinations were also performed. The construction and preservice examinations were usually completed prior to installation of the support members. Therefore, the extent of accessibility was not specifically known until the first inservice examination is completed. Integral attachment locations remaining to be examined were compared to locations similar in design and any expected limitations are listed in the table.

The pressure boundary passed the required preservice hydrostatic test and all subsequent pressure tests through the fifth refueling and inspection outage (RF05).

Complete examinations meeting the coverage requirements of ASME Code Section XI are performed on welds of similar configurations which utilized the same weld techniques, procedures and materials. The welds with complete examinations are subject to similar operating and environmental conditions as the partially examined welds. No service related discontinuities have been discovered on welds fully examined or those partially examined. Additionally, there is no industry history of ASME Class 2 service induced attachment weld failures. It is reasonable to expect that the unexamined portions are also acceptable.

The absence of significant integral attachment weld problems is further evidenced by ASME Code Case N-509 which allows a reduced sample size of only 10% of all integral attachments.

This Code Case has been approved at other nuclear facilities (e. g., Duane Arnold) and was incorporated into the 1995 Addenda of ASME Section XI. Fermi has not requested to implement this Code Case, which would reduce the inspection population to approximately 19 locations, during the first inspection interval. We are asking for partial relief of coverage on specific locations included in the 39 locations where examinations can be performed.

The average surface coverage for the incomplete examinations completed and listed in Table 1 is 80%. To obtain complete Code coverage at each location, the component support would have to be disassembled and the pipe clamp assembly removed. Temporary line support would have to be evaluated by engineering and installed as necessary. The additional engineering resources, time, field personnel, and radiation exposure required to attain full coverage is not consistent

.with the minimal risk associated with these items, as reflected by plant and industry experience l' as well as current Code requirements.

Radiation exposure for a best case location assuming a conservative effective (averaged) dose rate of Smr/hr and a minimum of 16 manhours to remove and reinstall the clamp assembly and .

inspect the location would result in at least 80mr additional exposure per location (approximately - ) '

640mr minimum accumulated dose). Note that this assumption'uses an effective averaged dose rate, and actual dose on a pipe and is often much higher. Removal of the clamps could actually increase the possibility of damaging other components such as nozzles and penetrations due to additional line stress. Additionally, the time for disassembly and reassembly does not assume i

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• l Enclosuie 2 to NRC-99-0040 Page 3 l

4 l mechanical difficulties such as temporary line support, seized bolts, and removal and  ;

reinstallation of welded 'ug retainers from the clamps, that will greatly increase the time and dose impacts.

ALTERNATIVE EXAMINATION: i Detroit Edison proposes that in addition to the partial surface examination of the exposed portion oflug welds and required base metal volume, that a supplemental visual examination to the extent practical by the examiner be performed. Additionally, leakage inspections were performed each inspection period per Category C-H.

The supplemental visual examinations for partial exams previously performed were conducted in a manner similar to ASME Section XI, VT-1. The purpose of the supplemental visual exam is to additionally determine the condition of the integral attachment, weld, or required base metal  !

volume in the areas with surface examination limitations. The visual examination is performed to identify conditions that would indicate impaired structaral integrity such as cracks, evidence of leakage, abnormal wear, corrosion / erosion, or physical damage on the accessible surfaces of the component. The visual examinations are performed within 24 inches of the component surface. l Mirrors and stificial lighting are used as determined to be necessary by the examiner. Previous examinations were performed by qualified and certified nondestructive examination personnel, knowledgeable of welding, material processing, and service induced defects, no defects were reported. This is consistent with the results of all nondestructive surface examinations completed i to date for ASME Class I and 2 integral attachments and the VT-3 of ASME Class 3 integral l attachments. All supplemental visual exams beginning at RF06 will be performed by ASME Section XI certified VT examiners. Any of the conditions listed above would be reported on the ]

data sheet required by the surface examination procedure and as required by the Fermi corrective action program. If any of the above conditions are reported, clamp disassembly will be performed as necessary to allow performance of a full surface examination.

Based on the coverage achieved, physical limitations, comparison of the Fermi ISI NDE Program scope as compared to current Code requirements, and low empirical probability of weld failure, Detroit Edison considers the proposed attemative examination to provide an acceptable level of quality and safety.

APPLICABLE TIME PERIOD:

Reliefis requested for the first 10-year inspection interval.

, Enclosure 2 to

', NRC-99-0040 Page 4 RR-A22 Table 1 Limited Examinations Category Weld Percentage Limitation i Alternate

/ Item Identification Complete Description Examination C-C/C3.20 PSFW-El1-3146- 83% per lug Clamp at restraint Ell- supplemental 606A-L 3146-G24 visual C-C/C3.20 PSFW-El 1-3146- 100% perlug Clamp at restraint Ell- supplemental 952A-L forlugs 3146-G36 visual B,E,H.K, 50%

for others C-C/C3.20 SW El1-3158- 87% per lug Lugs A,C,D, & F supplemental 583A-583F lugs B & E inaccessible due to lug visual 4 retainers on restraint Ell- )

3158-G52 i C-C/C3.20 SW-El 1-3158- 85% per lug Clamp at spring El1-3158- supplemental 7WC-7WH G51 visual C-C/C3.20 PSFW-E41-3162- 90 % Clamp at snubber E4l- supplemental 583A-F 3162-G20 visual .

C-C/C3.20 PSFW-E41-3172-592A-D 90 % Clamp at snubber E41-3172-Gl9 supplemental )

visual C-C/C3.20 PSFW E41-3172- 87% per lug lug retainers at E41-3172- supplemental

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l 625A-625D expected G14 visual C-C/C3.20 PSFW-El1-3177- 75% of pad Proximity of pipe to wall supplemental 718B weld length visual 4

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