NRC-98-0116, Forwards Revised Relief Requests RR-A21 & RR-A22,including Clarification of Requirements for Alternative Visual Exam as Requested During 980615 Conference Call.Relief Request RR-A1 Withdrawn Until RF-06 Refueling & Insp Outage

Forwards Revised Relief Requests RR-A21 & RR-A22,including Clarification of Requirements for Alternative Visual Exam as Requested During 980615 Conference Call.Relief Request RR-A1 Withdrawn Until RF-06 Refueling & Insp Outage

ML20236X277
Person / Time
Site:	Fermi
Issue date:	07/27/1998
From:	Fessler P DETROIT EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NRC-98-0116, NRC-98-116, NUDOCS 9808070258
Download: ML20236X277 (12)

Text

_-

Paul Fessler Plant Managei I Fermi 2 e

• 6400 North I)ixie liwy, Nesport, MI 48166 Tel: 734.586.5325 Detroit Edison W \

July 27,1998 NRC 98-0116 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington D C 20555 1

References; 1) Fermi 2 i NRC Docket No. 50-341 l

NRC License No. NPF-43 i

2) Detroit Edison Letter to the NRC, " Relief Request Update for the First Ten-Year Interval Inservice Inspection (ISI)

Nondestructive Examination (NDE) Program", NRC-98-0060, i dated April 16,1998

3) NRC Letter to Detroit Edison," Request for Additional Information (RAI) Regarding the Proposed Requests for Relief for the first 10-Year Interval Inservice Inspection (ISI)

Nondestructive Examination (NDE) Program at Fermi 2 (TAC No. MA1570)", dated May 28,1998

4) Detroit Edison Letter to the NRC, " Response to Request for Additional Information Relief Request Update for the if First Ten Year ISI NDE Program", NRC-98-0093, dated June 19,1998 i

Subject:

Clarification of the Requirements for Alternative Visual Examination Specified in RR-A21 and RR-A22 O w , wwa Requests for relief from the American Society ofMechanical Engineers (ASME)

Code,Section XI requirements were submitted to the Nuclear Regulatory Commission

.(NRC) for the Fermi 2 Nuclear Power Plant First Ten-Year Interval ISI NDE Program l

9000070258 900727 PDR ADOCK 05000461 G PDR A DTE Energy Company

(

USNRC-

, NRC-98-0116 Pa, ge 2 in Reference 2. This submittal was followed by a Request for Additional Information (RAI) in Reference 3. Detroit Edison responded to the RAI in Reference 4. In a conference call on July 15,1998, the NRC staffindicated that review of the RAI submittal (Reference 3) had been performed, and clarification of requirements for the.

alternative visual examination specified in Relief Requests RR-A21 and RR-A22 was requested.

RR-A21 and RR-A22 have been revised to include this information and are enclosed.

Also discussed was Relief Request RR-Al for ultrasonic examination coverage of reactor pressure vessel shell welds. The NRC reviewers indicated that they would prefer that these examinations be completed prior to approving this relief request and -

would likely defer its approval. 'Accordingly, Detroit Edison is requesting that RR-Al be withdrawn. RR-Al will be resubmitted following the RF-06 refueling and inspection outage.

If you have any questions or requests for additional information, please contact Mr.

Norman K. Peterson at (734) 586-4258.

Sincerely ,

j

. uLd L~~

Enclosures I

-cc: B. L. Burgess G. A. Harris

- A. J. Kugler M. T. Anderson (INEEL)

Regional Administrator, Region III

Supervisor, Electric Operators,

! Michigan Public Service Commission L -

r

Enclosure to

, NRC-98-0116 oi -

9 J

.1 1

ENCLOSURE 1~

+-

FERMI 2 NRC DOCKET NO. 50-341 NRC LICENSE NO. NPF-43 RELIEF REQUEST RR-A21 4 PAGES =

I i-I i-I f l 1

l

. -g  ;

i RELIEF REQUEST RR-A21 l

COMPONENT FUNCT!ON/ DESCRIPTION:

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

SYSTEMS:

Main Steam (B21)

Reactor Recirculation (B31) l Residual Heat Removal (El1)

Core Spray (E21)

Feedwater (N21)

ASME CODE CLASS:

Class 1 ASME SECTION XI REQUIREMENTS:

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 meul design thickness of 5/8" or greater.

' e 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 i by changes in the ASME Code. )

I The 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 I alternative. The engineering impacts mentioned are incurred in diverting limited l engineering resources away from other tasks. I L The structural integrity of the piping pressure boundary including welded attachments was originally demonstrated during construction by meeting the requirements of ASME j Section III. 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 l Preservice Inspection volumetric examinations were also performed. The construction I and preservice examinations were usuali :ompleted prior to installation of the support Pageiof4 l

L________-______________. L

l l

f me,mbers.. Therefore the extent of accessibility is not specifically know 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 l pressure tests through the fifth refueling and inspection outage (RF-05).

l Complete examinations meeting the coverage requirements of ASME Code Section XI j are performed on welds of similar configurations which utilized the same weld techniques, 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 ;ntegral attachment weld problems is further evidenced by ASME Code Case N-509 which allows a reduced sample size of only 10% of all integral attaclunents. 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 l 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 l locations where examinations can be performed.

The average surface coverage for the incomplete examinations completed and listed in Table 1 is 73%. To obtain complete Code coverage at each location, the component support would have to be disassembled and the pipe clamp assembly removed.

l Temporary line support would have to be evaluated by engineering and installed as j necessary. The additional engineering resources, time, field personnel, and radiation j exposure required to attain full coverage is not consistent with the minimal risk l 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 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 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.

Page 2 of 4

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 are performed at the completion of each refueling outage per Category B-P.

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 structural integrity such as cracks, evidence ofleakage, 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. Mirrors and artificial 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 compW :d to date for ASME Class 1 and 2 integral attachments and the VT-3 of ASME Class 3 miegral attachments. All supplemental visual exams beginning at RF-06 will be performed by ASME Section XI certified VT examiners. Any of the conditions listed above will be reported on the data s'neet 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 tie first 10-year inspection interval, l

l l

l Page 3 of 4 l '

RR-A21 Table 1 Limited Examinations Category Weld Percentage Limitation Alternate

/ Item Identification Complete Description Examination )

B-K 1/B10.10 FW-PS-2-B2- 70 % Clamp at spring B21-5353- Supplemental i AAl-AA4 Expected 1181 Visual B-K-l/B 10.10 FW-PS-2-D2- 70 % Clamp at spring B21-5355- Supplemental I AAl-AA4 IIDI Visual B-K-l/B 10.10 FW-RD-2-A2- 68% Clamp at spring B31-5357- Supplemental All AL4 HA2 Visual B-K-1/B 10.10 FW-RD-2-B2- 68% Clamp at spring B31-5359- Supplemental All-AL4 Expected 11B2 Visual B-K-1/B 10.10 SW-RS-2-A2-W4- 68 % Clamp at spring B31-5357- Supplemental W7 Expected liAl Visual B-K-1/B 10.10 SW-RS-2-B2- 68% Clamp at spring B31-5359- Supplemental W6A-W9A HB1 Visual B-K-1/B10.10 PSFW-El 1-2298- 69% per lug Clamp at rigid support Supplemental 833A-F El 1-2298-G04 Visual B-K-1/B 10.10 PSFW-El 1-2299- 50% per lug Clamp at spring El1-2299- Supplemental 836A-F Expected G03 Visual B-K-1/B 10.10 PSFW-El1-2299- 50% per lug Clamp at spring EIl-2299- Supplemental 781A-D G01 Visual B-K-1/B 10.10 SW.El 1 2327- 90% per lug 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 2WN2WR G02 Visual B-K-1/B l0.10 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 B-K-1/B10.10 SW-E21-3052- 88% per lug Clamp at spring E21-3052- Supplemental 2WS-2WV Expected G09 Visual B-K-1/B l 0.10 SW-E21-3053- 69% per lug Clamp at spring E21-3053 Supplemental 2WS-2WV G10 Visual B-K 1/B10.10 SW-E21-3053- 88% per lug Clamp at spring E21-3053- Supplemental 795A-795D G08 Visual B-K 1/B10.10 SW-N21-2336- 86% per lug Clamp Limitation Supplemental 12WC-12Wii Visual B-K-1/B 10.10 SW-N21-2336- 66% per lug Clamp Limitation Supplemental 12WJ-12WP Visual B-K-1/B 10.10 SW-N21-2336- 0% per lug inaccessible for .MT due to Supplemental 19WB-19WE lug retainers at N213537- Visual G29 B-K-1/B10.10 SW-N21-2336- 90% per lug Clamp at snubber Supplemental

( 9WB-9WE N21-3536-G29 Visual l

B-K l/810.10 SW-N21-2336- 90% per lug Clamp at spring N21-3537- Supplemental 2WC-2WN G26 Visual 1

f l Page4 # 4

Enclosure to l

, NRC-98-0116 ENCLOSURE 2 FERMI 2 NRC DOCKET NO. 50-341 NRC LICENSE NO. NPF-43 RELIEF REQUEST RR-A22 4 PAGES 1

1 i

l

RELIEF REQUEST RR-A22 COMPONENT FUNCTION / DESCRIPTION:

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

SYSTEMS:

Residual Heat Removal (El1)

High Pressure Coolant Injection (E41)

ASME CODE CLASS:

Class 2 ASME SECTION XI REQUIREMENTS:

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 of integrally 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.

4 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 III. Design, fabrication, installation, inspection, and examination satisfied the l 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 is not specifically know until the first inservice examination is completed. Integral attachment locations remaining to be Page1of4 L

expmined 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 (RF-05).

' Complete examinations meeting the coverage requirements of ASME Code Section XI l are performed on welds of similar configurations which utilized the same weld )

techniques, procedures and materials. The welds with complete examinations are subject i ta similar operating and environmental conditions as the partially examined welds. No service related discontinuities have been discovered on welds fully examined or those j 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 l asking for partial relief of coverage on specific locations included in the 39 locations f where examinations can be performed. l The average surface coverage for the incomplete examinations completed and listed in Table 1 is 87%. 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) l 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.

l. 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.

Page 2 of 4

r 4 .

ALTERNATIVE EXAMINATION:

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 are 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 structural integrity such as cracks, evidence ofleakage, 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. Mirrors and artificial 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 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 RF-06 will be performed by ASME Section XI certified VT examiners. Any of the conditions listed above will 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 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.

I l

l Page 3 of 4 L__._._ - ._m._.m. _ _ _ . _ . . _ _ . _ - ,_. . _.

RR-A22 Table 1 Limited Examinations Category W eld Percentage Limitation Alternate

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

for others C-C/C3.20 SW-El 1-3151 ~90% per lug Clamp at spring supplemental 4WE-4WK expected El 1-3151-G05 visual C-C/C3.20 SW-E l 1-3151- ~90% per lug Clamp at spring supplemental 10WC-10WH expected Ell-3151-G01 visual 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 retainers on restraint ElI-3158-G52 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 E41- supplemental 583A F 3162-G20 visual C-C/C3.20 PSFW E41-3172 90 % Clamp at snubber E41- supplemental 592A-D 3172-Gl9 visual C-C/C3.20 PSFW-E41-3172- 80% per lug lug retainers at E41-3172- supplemental 625A-625D expected G14 visual l

l I

i Page 4 of 4

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