2CAN119302, Forwards Addl Info Re First 10-yr ISI Relief Request B-B/3.1 Submitted Via ,In Response to NRC 921230 Safety Evaluation.Util Will Conduct Appropriate Insp for Denied Relief Requests B-J/B4.5 & C-E-1/C2.5 During 2R10 Outage

Forwards Addl Info Re First 10-yr ISI Relief Request B-B/3.1 Submitted Via ,In Response to NRC 921230 Safety Evaluation.Util Will Conduct Appropriate Insp for Denied Relief Requests B-J/B4.5 & C-E-1/C2.5 During 2R10 Outage

ML20059H091
Person / Time
Site:	Arkansas Nuclear
Issue date:	11/03/1993
From:	Yelverton J ENTERGY OPERATIONS, INC.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
2CAN119302, NUDOCS 9311090285
Download: ML20059H091 (6)

Text

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Enter;y Operations. Inc.

Rue 3 Ear 1370

= ENTERGY n.m o m

. To 5019M EW Jerry W.Yelverton su hes#

0;/ J ue 441 November 3,1993 2CANI19302 U S. Nuclear Regulatory Commission Document Control Desk Mail Station PI-137 Washington, DC 20555

Subject:

Arkansas Nuclear One - Unit 2 Docket No. 50-368 License No. NPF-6 Additional Information Concerning the First 10-Year Insenice Inspection Relief Requests 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, which ended March 26, 1990. These requests were for relief from cenain ASME Section XI Inservice Inspection (ISI) requirements because only limited examinations could be performed. The NRC subsequently requested additional information (RAI) concerning these relief requests in a letter dated September 10,1991 (2CNA099102). A response to the RAI and to questions raised during a conference call held on December 10.1991, was submitted on April 30,1992 (2CAN049208) An additional conference call was held on June 3,1992, to discuss the April 30,1992, submittal. An additional submittal, to resolve issues raised in the June 3,1992, conference call, was provided in a letter dated August 20,1992 (2CAN089210).

By letter dated December 30,1992 (2CNAl29205), the NRC provided its evaluation of the ANO-2 first ten-year intenal ISI relief requests. The NRC determined relief was appropriate or not nm sssary for 12 of 15 relief requests. Ilowever, in three cases (B-B/3.1, C-E-1/C2.5, and part of B-J/B4.5) relief was denied. For these three cases, Entergy Operations was given the option of performing the appropriate inspections at the next scheduled outage or resubmitting the requests with additional information.

Additional information to support relief request B-B/3.1 is included in the attachment. As described in greater detail in the attachment, second in'erval examinations have been conducted on the subject or similar welds to the 1986 Code, which yield cumulative coverages greater than those required by the Code of Record for the first interval. Considering this, Entergy Operations believes that the safety benefit of performing these first intenal examinations during the next refueling outage does not justify the cost or dose involved. }

However, Entergy Operations has scheduled performance of the appropriate inspections as a 1

9311090285 931103 E -

PDR ADOCK 05000368 "

S I G PDR k[Y

U. S. NRC

' November 3,1993 j 2CANI19302 Page 2 contingency if reliefis not approved by the NRC piior to the next refueling outage (2R10).

Entergy Operations will conduct the appropriate inspections for denied relief requests B- 1 J/B4.5 (part) and C-E-1/C2.5 during 2R10. Additional clarifying information for these two relief requests is also provided for completeness in the attachment.

Entergy Operations requests prompt review of the additional information for relief request B- ,

B/3.1 in order to climinate any unnecessary expenditures and dose ($30,000 and 4 rem, I respectively) associated with conducting the inspections during 2R10 (currently planned to  !

begin March 12,1994). If you have any questions regarding this submittal, please contact me.  ;

i Very truly yours,

&}

!JWY/jjd N

Attachment  ;

I cc: Mr. James L Milhoan '

Regional Administrator j U. S. Nuclear Regulatory Commission Region IV l 611 Ryan Plaza Drive, Suite 400 i Arlington, TX 76011-8064 i NRC Senior Resident Inspector  !

i Arkansas Nuclear One - ANO-1 & 2 Number 1, Nuclear Plant Road ,

Russellville, AR 72801 ,

i Mr. Roby B. Bevan, Jr.- i 1 NRR Project Manager Region IV/ANO-1 l U. S. Nuclear Regulatory Commission i NRR Mail Stop 13-H-3 i

, One White Flint North  !

11555 Rocksille Pike j Rockville, MD 2085' l

] Mr. Thomas W. Alexion NRR Project Manager, Region IV/ANO-2  !

U. S. Nuclear Regulatory Commission NRR Mail Stop 13-II-3 One White Flint North 11555 Rockville Pike  !

Rockville, MD 20852  !

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Attachment to

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ADDITIONAL INFORMATION IN RESPONSE TO NRC SAFETY EVALUATION DATED DECEMBER 30,1992 Entergy Operations has reviewed the Safety Evaluation (SE) performed by the NRC of the. i first 10-year interval ISI relief requests for ANO-2. Entergy Operations' response te the specific sections of the Safety Evaluation where the NRC has denied reliefis listed below.  ;

Relief No. B-B/H3.1 i

In section 2.0(C), relief was denied for the Code Category B-B/ Item No. B3.1, steam  :

generator 2E-24A circumferential weld 03-002 and meridional welds03-003, 03-004, and 03-005, on the basis that insufficient technical justification was provided for failing to attain the Code required coverage (i.e.,5% circumferential and 10% meridional). The SE t stated that review of drawing ISI-203 indicates that the minimum Code-required volume can be examined and also that the examination should have been extend < to include other .

accessible portions of the same weld, even if only a one sided exam cousa be performed.

A.s previously stated in Entergy Operations' submittal of August 20,1992, the examination of circumferential weld 03-002 was limited to scanning with a %V calibration from the lower head side of the weld only, due to the blend radius of the stay cylinder base. The examination of this weld was performed for 12 inches of weld length starting at meridional weld 03-003 and extending towards meridional weld 03-004. The 1974 Edition of the .

ASME Section XI Code through Summer 1975 Addenda (hereafler referred to as the 74S75 Code) requires that 5% of the length of this circumferential weld be volumetrically examined. Article 4 of the ASME Section V Code states that the required examination volume shall be scanned in two directions. Two directional coverage of this examination volume cannot be achieved because: 1) scanning can only be performed from the lower head side of the weld and; 2) scanning is limited to a %V calibration which prohibits i attainment of the second opposing direction coverage by reflecting the sound off the inner diameter surface. The premise of two directional coverage is that a flaw oriented in such a plane that it cannot be observed in one direction should be detectable by a scan from the i second opposing direction. Entergy Operations believes the intent of the 74S75 Code is two directional coverage of 5% of the examination volume and that this requirement cannot be met by scanning more of the weld length from only one direction (since a  ;

hypothetical flaw oriented in a plane parallel to the beam path introduced from the lower head side surface may go undetected).  ;

A second inspection interval examination was performed during the ANO-2 2R9 refuehng outage on lower head to lower extension ring circumferential weld 03-008. This circumferential weld is the same Code Category and Item Number as the circumferential  !

weld in question, and is also located on the lower head of steam generator 2E-24A. 4 Calculation of the " effective coverage" (i.e., an algebraic combination of one and two directional angle-beam scanning coverage expressed in terms of equivalent Code-required  ;

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. two directional coverage) achieved for the entire length of circumferential weld 03-008 reveals that 97% and 100% coverage was attained for reflectors oriented parallel and transverse to the weld, respectively. The overall percentage of scanning coverage achieved on the entire length of this weld, per 1986 ASME Section XI Code requirements, represents a considerable quantity of examination volume in comparison with the 74S75 Code requirement of 5% for the weld in question, and provides substantial demonstration of the integrity of the steam generator lower head circumferential welds.

For meridional welds03-003, 03-004, and 03-005, examination was limited to scanning with a %V calibration from one side of the peel segment weld only, due to a nozzle (hot leg or cold leg) obstruction on the other side of the weld. The examination of these welds was performed for 10 inches of weld length starting at 30 inches and extending to 40 inches above weld 03-002. If this scan limitation existed for the entire length of these welds, then the same concept as above would apply. However, as a result of a second inspection interval examination performed during the ANO-2 2R9 refueling outage on peel segment weld 03-005, it is now known for this weld, and suspected for welds03-003 and 03-004, that sufficient weld length exists both above and below the hot and cold leg nozzle obstructions to enable the performance of a second direction scan from the other side of the peel segment. For example, peel segment weld 03-005 has a total weld length of 78 inches. The hot leg nozzle prohibits or 1:mits scanning for 56 of these inches from one side of the peel segment, while for the remaining 22 inches of weld length (11" above and 11" below nozzle obstmetion), uninhibited scanning can be performed from both sides of the weld. Calculation of the " effective coverage" achieved for the entire length of meridional weld 03-005 reveals that 81% and 83% coverage was attained for reflectors oriented parallel and transverse to the weld, respectively. The overall percentage of scanning coverage achieved on the entire length of this weld, per 1986 AShfE Section XI Code requirements, represents a considerable quantity of examination volume in comparison with the 74S75 Code requirement of 10% for each of the three meridional welds in question, and provides substantial demonstration of the integrity of the steam generator lower head meridional welds.

In summary, additional scanning of weld 03-002 will not accomplish the 74S75 Code required two directional coverage of 5% of the examination volume for the reasons stated above. For meridional welds03-003, 03-004, and 03-005, it is now known for one of these welds, and believed for the other two, that the 74S75 Code requirement of 10%

could have been fulfilled during the first inspection interval. However, based on a total effective coverage achieved approaching 100% for circumferential weld 03-008 and a total effective coverage achieved in excess of 80% for meridional weld 03-005, ample evidence exists to validate the integrity of the steam generator lower head circumferential and meridional welds. The 1986 AShfE Section XI Code examination coverage achieved for circumferential weld 03-008 is approximately 20 times more than that required for circumferential weld 03-002 per 74S75 Code requirements, and the 1986 ASME Section XI Code examination coverage achieved for meridional weld 03-005 more than doubles the collective examination coverage requirement for all three meridional welds per 74S75 Code requirements.

Attachment to a 2CAN119302 i

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The examination coverage of these welds is at issue because of the 74S75 Code  !

requirement to only examine partial weld lengths (i.e., 5% circumferential and 10% i meridional). The question of how to adequately fulfill these' requirements, when a  ;

scanning limitation exists, has' historically been a subject of debate. The Winter .'75-Addenda eliminated the partial weld lengths requirement. The ASME Section XI Code now requires examination coverage of the entire length of these welds; therefore, this particular issue should not appear again. Entergy Operations recognizes that ASME l Section XI Code examinations are not intended to serve a dual purpose (i.e., double crediting examinations performed during 2R9 to satisfy first and second inspection interval examination requirements). However, by virtue of having performed second inspection -

interval examinations during ANO-2's last refueling outage (and prior to resolution of the first interval relief request), the stmetural integrity of the steam generator lower head  :

circumferential and meridional welds has been verified. Entergy Operations believes this ,

addresses the most important aspect of the NRC's concern and requests that the NRC f consider all of the above as a basis for relief from the first 10-year requirements and to preclude the expense of further examinations. The estimated dose and plant cost to l perform these examinations, including required support, are four rem and $30,000, ,

respectively. Ilowever, to bring this issue to closure, tentative plans have been made to l perform examinations of welds03-002, 03-003,03-004, and 03-005 during 2R10. The examinations will be performed unless reliefis approved.  ;

Relief No. B-J/B4.5 In section 2.0(H), relief was denied for Code Category B-J/ Item No. B4.5, shutdown '

cooling piping weld 25-017, on the basis that insuflicient technical justification was  !

provided for failing to attain the Code required coverage of 100% of this circumferential .

piping weld. Additionally, the NRC further commented that since the circhmferential l scans were fully performed, the estimated coverage of 0-25% should have been higher. 3 This topic is under review by an Entergy Operations inservice inspection peer group-composed of engineering representatives from each of Entergy's nuclear sites. Entergy .

Operations is also monitoring activity within ASME for possible guidance pertaining to this issue. In many cases, a potential flaw of an axial orientation is not considered as critical as a potential flaw of a circumferential orientation. This is dependent on the loadings (e.g., mechanical or pressure) to which the component is subjected. q Consequently, a circumferential scan capable of detecting axial flaws may not be regarded ,

on equal terms with an axial scan capable of detecting circumferential flaws. In this  !

particular example, Entergy Operations conservatively assigned primary weight to the  ;

axial scan and placed lesser credit on the circumferential scan.

i Entergy Operations agrees with the NRC assessment that an axial scan could have been  !

performed and will perform an axial scan of this piping weld during 2R10. An attempt i will first be made to perform the required examination from the tee side of the weld with a  !

sufIiciently long metal path to enable the accomplishment of two directional axial coverage  !

from the tee side. If the examination is prohibited or limited by the configuration of the

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Attachment to

,. 2CANI19302  !

I' Page 4 of 4

. tee, the pipe clamp _will be removed to enable the performance of the required axial scan j '

from the pipe side of the weld.

Relief No. C-E-1/C2.5 i

In section 2.0(O), relief was denied for Code Categog C-E-1/ Item No. C2.5, shutdown '!

cooling integrally welded attachment 59-049W, on the basis that in the original relief j request submittal of August 31, 1989, it was stated that the interfering pipe clamp -  ;;

obstruction would be removed to allow for the complete surface examination of this attachment. As stated in the Entergy Operations submittal of August 20,1992, no evidence can be found that the pipe clamp was ever removed.

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. Entergy Operations will remove this pipe clamp during the next scheduled refueling outage to enable the complete surface examination of this integrally welded attachment.

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