2CAN089210, Forwards Response to NRC 910910 Request for Addl Info Re First 10-yr Inservice Insp Relief Requests,Per 911210 & 920603 Telcons.Under Current Code Rules,Indentification Tag Would Not Cause Exam Limitation

Forwards Response to NRC 910910 Request for Addl Info Re First 10-yr Inservice Insp Relief Requests,Per 911210 & 920603 Telcons.Under Current Code Rules,Indentification Tag Would Not Cause Exam Limitation

ML20114B237
Person / Time
Site:	Arkansas Nuclear
Issue date:	08/20/1992
From:	James Fisicaro ENTERGY OPERATIONS, INC.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
2CAN089210, 2CAN89210, TAC-M76001, NUDOCS 9208250263
Download: ML20114B237 (8)

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-E===___ Entergy Operations cugust 20, 1992 2CAN089210 U. S. Nuclear Regulatory Commission Document Control Desk Mall Station F1-137 Washington, DC -20555

Subject:

Arkansas Nuclear One - Unit 2 Docket No. 50-368 License No. NPF-6 Additional Information Concerning the First Ten Year inservice Inspection Relief Requests (TAC No. M76001)

Gentlemen:

In letter 2CAN088915, August 31, 1989, Entergy Operations submitted relief requests for Arkansas Nuclear One, Unit 2 (ANO-2) for the first 10-year interval. These requests were for relief from certain ASME Section XI Inservice Inspection (ISI) requirements because only limited examinations c.ould be performed. The NRC subsequently requested additional information (RAI) concerning these relief rcquests in letter dated September 10, 1991 (2CNA099102). A conference call was held on December 10, 1991, to discuss the September 10, 1991, request.

In letter dated February 13, 1992 (2CAN029202), Entergy Operations stated that ANO-2 war unable to provide a specific response to the RAI but committed to submit a best. estimate of the percentage of the Code-regaired coverage. In letter dated April 30, 1992 (2CAN049208),

Entergy Operations submitted a best estimate for each weld. The percentages of the Code-required coverage were estimated and placed into four categories. These categories are 0 to 25%; 26 to 50%; 51 to 75%;

and 76 to 100% of the Code-required coverage of the weld.

As a result of this submittal, a cor.ference call was conducted on June 3, 1992, to discuss the April 30, 1992, submittal. Durf g this conference call, certain additional questions were raised on the previously submitted relief requests. The attachment to this submittal provides the ANO response to the NRC Staff's additional questions.

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-U.:S, NRC Augustl20, 1992' Page 2' Should you have any questions regarding this issue, please contact me'.

ll Very. truly yours.

I M

James Fisicato j Director, Licensing JJF/ RWC/sj f I Attachment cci Mr. James L. M11hoan  !

j U. S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive. Suite 400 Arlington, TX 76011-8064 NRC Senior Resident Inspector Arkansas Nuclear one --ANO-1 & 2 Number 1, Nuclear Plant Road Russellville, AR 72801 Mr. Thomas W. Alexion NRR Project Manager, Region IV/ANO-1  !

U. S. Nuclear Regulatory Commission

- NRR Mail Stop 13-H-3

.One White Flint North 11555 Rockville Pike Rockville, Maryland 20852 Ms. Sheri-R~ Peterson NRR Project Manager, Region IV/ANO-2 l U. S. Nuclear Regulatory Commission L NRR Mail'Stop 13-H-3 On1 White' Flint-North 11555 Rockville Pike-Rockville, Maryland.20852 p-,

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.. 8 RESPONSES TO THE REQUEST FOR ADDITIONAL INFORMATION CONCERNING THE FIRST 10-YEAR INTERVAL RELIEF REQUESTS A. Request for Relief C-F/C2.2

1) Weld #53-021A is obstructed by an identification tag. Is this obstruction permanent? If not, is there a real impracticality for examining this weld?

An identification tag is welded over the top of a portion of this elbow longitudinal weld and prohibited the volumetric examination of 100%_of it. -The identification tag is a permanent obstruction.

Note: Under the current Code rules, this tag would not cause an examination limitation because it is outside the 2.5t scan surface area from the intersection with the circumferential weld.

2) Weld #55-0298 is obstructed by a nameplate welded across the weld. The estimated coverege is lic' ed 51-7st. The estimate for the obstructed area appears excessive (e.g. to obstruct 50%

of the weld in a 12" diameter pipe, the nameplate would have to be nearly 19" long). Is this estimate correct?

The estimate 1:. correct. A nameplate obstruction length of 19 inches would be required to create a 50% limitation only if this were a 12 inch diameter circumferential wela. However, as listed in the April 30, 1992, submittal, weld 55-029B (C-FiC2.2) is a reducer longitudinal weld.

3. Request for Relief C-E-1/C2.1 (Weld #59-049W): The Licensee's

-proposed alternative was to remove the hanger support clamp that obstructed the required examination. Accordingly, the examination can be accomplished and relief is not required. -Has the examination been accomplished?

A hange support clamp 1s located adjacent to the area where the attachment is integrally welded to the pressure boundary. This prohibited the surface examination of 100% of this attachment weld.

There is r_o evidence that the support clamp was ever removed te allow for ccmplete examination of this weld.

Note: 1he attachment thickness is only 0.280 inch. By current Code rules. t s Class 2 attachment weld would not require examination due u :o u.g less than 0./5 inch.

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For the following casec, the information is incomplete and inadequate for justifying relief:

C. ~ Request for Relief B-B/B3.1 (Weld #'s03-002, 03-003,03-004, and 03-005): The Code only requires 5% of each circumferential weld and 10% of each longitudinal weld be examined. Drawing 41S1-203 does not support the impracticality of this request. Please provide a more detailed technical description of the limitation to support the determination that ovec 90% of the subject welds :oul.d not be examincd.

Listed below is a technical description of the limitation for circumferencial weld 03-002:

e Examination performed from lower head side of weld enly due to blend radius of stay cylinder base e Condition exists 360 around the circumference of the weld

• - Scanning limited to a 1/2 V calibration due to cladding

• Scan path of 12 inches starting weld 03-003 and extending towards weld 03-004 e 100% circumferential scan was perf ormed e See General Ccmments 2, 3, and 4, provided below, for additional information Listed below is a technical description of the limitation for meridional welds03-003, 03-004, and-03-005:

• Examination performed from one side of peel segment weld only.

This limited examination was due to nozzle (Hot Leg and Cold

?egs) obstruction r.n other side of weld e Scanning limited to a 1/2 V calibration due to cladding

• Scan path of 10 inchct starting at 30 inches and extending to 40 inches attve weld 03-009 e 100% circumferential scan was performed e See General Comments 2, 3, and 4, provided below, for additional information l

D. . Request for Relief B-B/B1,2 (Weld #'s C1-008,01-016, 01-017,01-018, and 01-019): Thc Code only requires that 5% of each circunferential weld and 10% of each longitudinal weld to be examined, Drawing #ISI-201 does not support the impracticality of this request, Picase provide a more detailed technical description of the limitation to support the determination that over 90% of the subject welds ceuld not be examined.

Listed below is a technical description of the limitation for circumferential weld 01-008:

+ Limited volumetric examination due to proximity f flow baffle assembly that prohib3ted full coverage of the required examination volume e Scanned from 102 to 131.1 e Scanning limitatlan exists 360 around vessel circumference e Scanning limited to a 1/2 V calibration due to cladding e See General Commentt: 2 and 4, provided below, for additional information Listed below is a technical desertption of the limitation for circumferential weld 01-016:

• Limited volumetric examination due to t roximity of nozzles on upper shell side of weld that prohibited full coverage of the required examination volume e Scanning was limited to a 1/2 V t alibrationjjy(;to cladding wh e- Note on data sheet states that " areas selected were to minimize obst uctions"

• See Generni Comments 2 and 4, provided below, for additional information Listed below is a technical description of the limitation for longitudinal wr ds01-017 01-018, and 01-019:

• Limited volumetric exar1 nation due to nozzles on both sides of upper shell longitudinal welds that prohibited full coverage of the required examination volume.

• Scanning was limited to a 1/2 V calibration due to c: ' ding Note on data sheet states that " areas selected were minimize obs t ructions" e See General Comments 2 and 4, provided below, for additional information

E. Requesti for Relief C-A/C1,1 (Weld #'s03-030, 03-031,03-032, and 03-033 on SG #1, and 04-030,04-031, 04-032, and 04-033 on SG #2):

The Code only requires that 20% of the length of each steam generator circumferential weld be examined, ' Drawing #ISI-203 does not support the impracticality of this request, Please provide a more detailed technical description of the limitation ta support the determination that os Jr 80% of the subject welds could not be exsmined.

Listed below is a technical descriptian of the limitation for circumferential welds 03-030/06-030, 03-031/04-031, 03-032104-032:

e Limited volumetric examina'. ion due to insulation support ring and insulation brackets that prohibited full coverage of the required examination volume e Insulation support ring obstruction exists 360 around vessel circumference e This obstruction affected welds 03-030/04-030, 03-031/04-031, and 03-032/04-032 to a varying extent depending upon proximity relative to each weld, e The affect is essentially constant 360 around vessel circumference e 20% uniformly distriouted among three areas around vessel circumference is subject to t he same physical obstruction at essentially any_ location e 100% circumferential scan was performed-

• See General Camments 2 and 4, provided below, far additional info rmation Listed below is a technical description of the limitation for circumferential welds 03-033/04-053:

-* Limited solumetric examination due to insulation supports that prohibited full coverage of the required examination volume e It.sulation supports located in increments nround vessel circumference-e 20% uniformly distributed among thrae areas arcund vessel circumference is subject to tha same physical obstruction at essentially any location e Sen General Comments 2 and 4, provided below, for additional information

L F. General Questions Regarding the April 30, 1992, Submittal

1) In cases where only a percentage of the weld length is required to be examined, it is not clear if the estimated coverage is based on the total weld volume or Code-required volume. Please d<. scribe how the " Estimated Coverage" was determined.

In those cases where only a percentage of the weld length is required to be examinea, +ha rtimated covarage is based upon ,

the Code-required examination volure with the exception of the Category B-A welds. For Category 1-A welds, an attempt was made to examine 100% per Regulatory Guide 1.150 as noted in the Remarks Sec tion.

2) The Staff recognizes that a partial examination provides at -

least a sampling of a given weld and een provide some assurance of the continued structural integrity. For cases where the estimated coverage is listed as 0-25%, are there any cases where 0: of the exams were completed? Likewise for the 76-100%

examinations, are there cases where 90% or more of the examinations were completed?

I. number 25-017 was the only component that fell into the categoty of 0-25%, which is a reducer to tee circumferential piping weld. As stated in the Remarks Section for 25-017, an axial scan to look for reflectors ordeuted parallel to the weld was not performed duc to a hanger support bracxet and tee configuration. A 100% circumferential scan for reflecters oriented perper dicular to the weld was accomplished.

See General Comment 4, provided below, for information concerning those examinations in the 76-100% category.

3) Since the subject relief requesto are "past history", it is undecstandable that some data may no longer exist. . Ilowever, the affected components and associeted drawings must exist.

Please explain 917 a more accurate " engineering judgeaent"-

(within i 5%) of the coverage carnot be made based on the drawings and visual examination of the actual components.

Other plants have done this.

See General Comment 2, provided below for a responseLto tnis

. question.

GENERAL COMMENT

S 1)- The subject examination limitations .re for components examined during the first inspection Interval to 1974 Edition, Summer 1975 Addenda of the Code requirements. The data has been reviewed in an effort to make an estimate of the coverage achieved using

' engineering judgement". At this point in time. ANO must rely on

- the existing information listed on the historical data records since the first inspection interval is complete. ANO believes that the optimum areas in these cases were chosen and that maxin.wu coverage was achieved.

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2) As has-been previously' stated, the-time frame-during which these examinations were performed dio not require the same level of details as current standards. ANO-2's current ISI program requires much greater emphasis on documenting examination limitations.

Typically, the existing historical data has dimensional <information-regarding the location of the physical obstruction along with a o description of it. This is fairly standard for data for that time frame.

The critical- information that is lacking, by today's standards, includes a profile of the weld, actual ohysical measurements of the weld width and length,.and wall thickness readings in increments across the width of the weld at a representative location. ,

This information is required to develop a coverage plot and to quantify the examination volume. The scan paths are then d awn in based upon the interfering obstruction to calculate its impact on the examination coverage.

This'is considered the only approach that has a sound engineering basis. -An estimate within i 5% based solely on an engineering judgement of the available information is not considered to be

-reliable or-accurate-and has no tangible, enginearing-based technical merit.

3) In several cases, the physical obstruction or configuration that is

-the cause of the examination limitation only affects the axial scan performed to detemt reflectors oriented parallel -to the weld. The circumferential scan performed to detect reflectors oriented 2 perpendicular to the weld is unaffected.

This was' censidered in the coverage estimate for the applicable components.; It was not given equal weight with the axial scan-in the coverage estimate however, since ANO did not view this as being asLcritical of an examination.

- 4) As discussed in Comment 2 above, an ' estimate of coverage within-1 5%~

tolerance is not possible without a coverage plot. Consequently, a determination of whether coverage greater than 90% was achieved is not possible.

Code Case N-460 was approved by the NRC in Revision 8 of Regulatory Guide 1.147,: published in November 1990. This was over a year after-the original. relief requests were submitted and over six months

-af ter the completion .of the ANO-2 first Inspection Interval.

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