1CAN099901, Forwards Responses to 990831 RAI Containing follow-up Questions Discussed on 990823-26,in Support of SG Outer Diameter Intergranular Attack Alternate Repair Criteria. Revs to Proposed TSs Included in Attachments

Forwards Responses to 990831 RAI Containing follow-up Questions Discussed on 990823-26,in Support of SG Outer Diameter Intergranular Attack Alternate Repair Criteria. Revs to Proposed TSs Included in Attachments

ML20211N986
Person / Time
Site:	Arkansas Nuclear
Issue date:	09/07/1999
From:	Hutchinson C ENTERGY OPERATIONS, INC.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20211N991	List: 1CAN099901, Forwards Responses to 990831 RAI Containing follow-up Questions Discussed on 990823-26,in Support of SG Outer Diameter Intergranular Attack Alternate Repair Criteria. Revs to Proposed TSs Included in Attachments ML20211P006
References
1CAN099901, TAC-MA4761, NUDOCS 9909130116
Download: ML20211N986 (16)

Text

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e Entergy Operations,Inc.

v 1448 S H 333 Russt%4e. AR 72801 Tel 501858-4888 C. Randy Hutchinson Vce Presdent Owations AND September 7,1999-1CAN099901 U. S. Nuclear Regulatory Commission Document Control Desk Mail Station OPl-17 Washington, DC 20555

Subject:

Arkansas Nuclear One - Unit 1 Docket No. 50-313 License No. DPR-51 Additional Information in Support of Steam Generator Outer Diameter Intergranular Att.ack Alternate Repair Criteria (TAC NO. MA4761)

Gentlemen:

By )|letter dated May 14,1999]] (ICAN059901), Entergy Operations submitted proposed Arkansas Nuclear One, Unit 1 (ANO-1) technical specification (TS) changes to revise once through steam generator tubing surveillance requirements to provide alternate repair criteria (ARC) for volumetric outer diameter intergranular attack (ODIGA). Much of the basis for the proposed TS changes is contained in topical report BAW-10235P, " Management Program for Volumetric Outer Diameter Intergranular Attack in the Tubesheets of Once-Through Steam Generators," Rev. O. On June 17,1999 (ICAN069905), Entergy Operations submitted a non-proprietary version of the topical report.

Follow-up questions were discussed with the Staffon August 23 through 26,1999. The NRC Staff formally transmitted these questions in a request for additional information (RAI) dated  ;

August 31,1999 (ICNA089905). Entergy Operations' responses to the RAI are attached. j i

Several revisions to the proposed TSs have been made in conjunction with the RAI responses.

The revisions do not affect the no significant hazards consideration or environmental impact evaluation included in the )|May 14, 1999, letter]] since the changes provide clarifications or more conservative criteria than initially proposed. The revisions to the proposed TSs are  :

included in the attachments.

The responses to the RAI have also necessitated a revision to BAW-10235P, Rev. O. The proposed changes to the topical report are described in the attachments. Revision 1 to j BAW-10235P will be submitted by September 10,1999. ) ,

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I September 7,1999 1CAN099901 Page 2 I Should you have any questions concerning this submittal, please contact me.

Very tmly yours, .

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CRWid' attachments -  ;

1 To the best of my knowledge and belief, the statements contained in this submittal are true.

SUBSCRIBED AND SWORN TO before me, a Notary Public in and for r[ e County and the State of Arkansas, this _'7 day of bir,.lm ,1999.(/

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1. D emeusue.mmus Notary My CommissiPublic[

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..- ...- U. S. NRC -

September 7,1999 ' l 1CAN099901 Page 3 cc: Mr. Ellis W. Merschoff Regional Administrator U. S. Nuclear Regulatory Commission j

' Region IV 1 611 Ryan Plaza Drive, Suite 400 -

Arlington, TX 76011-8064 NRC Senior Resident Inspector Arkansas Nuclear One P.O. Box 310 i London, AR 72847 Mr. Nick Hilton NRR Project Manager Region IV/ANO-1

. U. S. Nuclear Regulatory Commission NRR Mail Stop 04-D-03 One White Flint North 11555 Rockville Pike Rockville, MD 20852 Mr. David D. Snellings Director, Division ofRadiation l Control and Emergency Management Arkansas Department of Health

- 4815 West Markham Street Little Rock, AR 72205 i

1 j

.;- .- Attachment 1 to 1CAN099901 Page1of13 Additional Information to Support Intergranular Attack Alternate Repair Criteria NRC Question No.1 A probability of detection curve is included as Figure 18 in BAW-10235P, Revision 0.

The staff requests additionalinformation to better determine how the curve applies to the ODIGA degradation at ANO-1. Provide the NRC with a list that includes the depth, voltages, eddy current size measurements (if available), tube identity, flaw location on the tube, and the plant from which the pulled tube data were obtained for each flaw that were used in the constmetion of the curve.

Entergy Operations Response The following table provides the requested data for the probability of detection (POD) curve used for the outer diameter intergranular attack (ODIGA) alternate repair criteria (ARC) for once-through steam generator (OTSG) tube flaws to be utilized at Arkansas )

Nuclear One, Unit 1 (ANO-1).

The field plus-point voltage data was not available for the flaws in Table 1-1. The POD curve is used to determine what percentage of undetected flaws have a remote chance of leaking (e.g. >70% through-wall). The curve conservatively uses IGA data from other OTSGs in determining the undetected population of flaws greater than 70%through-wall (TW). If the ANO-1 upper tubesheet data was considered a' w the population of defects would meet the performance criteria for detection establis' ' n Appendix H of the EPRI i

Guidelines. This is illustrated in generic ETSS #96000 . #96011 located in the EPRI database.

TABLE 1-1 TEST # ROW COL REF LOC CAL DEF MAX FIELD PLANT (IN) DEPTH BOB

(%TW) (%TW) )

1 91 55 ISS +7.6 212 0 0 TMI l 2 59 58 07S +26.3 5 IGA 2 ONS3 3 33 31 10S +4.6 36 IGA 4 ONS3 4 97 91 LTS +9.9 86 IGA 4 CR3 l 5 97 91 LTS +3.9 86 IGA 5 CR3 l 6 106 32 LTS +6.5 5 IGA 8 CR3 l 7 106 32 LTS -3.3 5 IGA 9 CR3 l 8 106 32 LTS +10.5 5 IGA 10 CR3 9 106 32 LTS +16.7 5 IGA 11 CR3 l

e Attachment I to ICAN099901 Page 2 of 13 TABLE 1-1 (cont)

TEST # ROW COL REF LOC CAL DEF MAX FIELD PLANT

.(IN) DEPTH BOB

(%TW) (%TW) 10 106 32- LTS +11.2 5 IGA 12 CR3 11 52 51 LTS + 11.1 8 IGA 13 CR3-12 106 32 LTS- ' +5.4 5 IGA 14 CR3 13 106- ~32 LTS -1.7 5 IGA 15 CR3 14 106 32 LTS +10.6 5 IGA 16 CR3 15 106 32 LTS -2.4 5 IGA 17 CR3 16 41 44 LTS +10.9 7 IGA 18 CR3 17 41 44 LTS- +14.4 7 IGA 19 CR3 18 106 32 LTS +15 5 IGA 20 CR3-19 41 44 LTS + 8. 6 7 IGA 22 CR3

'20 90 28 LTS +13 52 IGA 23 CR3 21 41 44 LTS +12.7 7 IGA 24 CR3 22 106 32 LTS +7. 8 5 IGA 25 CR3 23- 52 51 LTS +15 8 IGA 26 CR3 24 20 48 LTS -2.2 40 IGA 27 ONSI 25 41 44 LTS +7.9 7 IGA 28 CR3 26 IGA 106 32 LTS +9 5 29 CR3 27 41 44 LTS +14 7 IGA 30 CR3 28: 106 32 LTS -2.8 5 IGA 31 CR3 29 52 51 LTS +16.2 8 IGA 32 CR3 30 52 51 LTS +12.8 - 8 IGA 33 CR3

)

31 52 51 LTS +6.2 8 IGA 34 S/N CR3 )

32 41 44 LTS +9.3 7 IGA 35 CR3 l

33 79 63 UTS -3.4 6 IGA 35 13 ANOl 34 106 32 LTS +14.8 5 IGA 36 S/N CR3 35 41 44 -LTS +15.9 7 IGA 37 CR3 )

36 79 63 UTS +4.0 6 IGA 38 35 ANOl 37 106 32 LTS +9.7 5 IGA 38 CR3

-38 106 32 LTS +13.6 5 IGA 39 CR3 )

39 106 32 LTS +8.8 5 IGA 40 S/N CR3 40 -41 44 LTS +6 7 IGA 41 CR3 41 106 32 LTS +11.4 5 IGA 42 S/N CR3 42 20 48 LTS -1 40 IGA 43 NDD ONSI 43 80 18 UTS -9.9 502 IGA 44 38 ANOl 44 90 28 LTS +12.5 52 IGA 45 CR3 )

45 97 91 LTS +9 86 IGA 46 S/N CR3 46 52 51 LTS +8.5 8 IGA 47 S/N CR3 47 97 ' 91 LTS +12.2 86 IGA 48 CR3

..- , - Attachment I to ICAN099901 Page 3 of13 TABLE 1-1 (cont)

TEST # ROW COL REF LOC CAL DEF MAX FIELD PLANT I (IN) DEPTH BOB

(%TW) (%TW) 48 90- 28 'LTS +14.2 - 52 IGA 49 CR3 j 49 109- 30 LTS +8.4 5 IGA 50- 30 CR3 l 50 106 32 LTS +7 5 IGA 51 CR3 51 80 18 UTS -7.6. 502 IGA 52 3 ANOl 52 90 28 LTS +13.4 52 i IGA 53 CR3 53 41' 44 LTS +12.2 7 IGA -54 S/N CR3 54 90 28 LTS +6.4 52 IGA 56 S/N- CR3 55 83 47 UTS -8.9 219 IGA 58 42 ANOl

-56 ' 90 28 LTS +11.8 52 IGA 60 CR3 57 79 63 UTS -4.4 6 IGA 61 27 ANO1 58 90 28 LTS +14.6 52 IGA 62 CR3 '

59 80 18 UTS -12.0 502 IGA 65 34 ANOl l 60 73 8 UTS +3.7 134 IGA 70 36 ANOl

_ 61 68 46 LTS -0.6 15 IGA 76 CR3 62 80 18 UTS -6.7 502 IGA 76 40 ANOl 63- 79 63 UTS -2.9 6 IGA 77 32 ANOl 64 83 47 UTS -6.5 219 IGA 83 36 ANOl 65 79 63- UTS -3.7 6 IGA 88 38 ANO1 66 73 8 UTS +5 134 IGA 100 60 ANOl  !

67 73 8 UTS +5.5 134 IGA 100 84 ANOl 68 73 8 UTS +0.9 134 IGA 100 84 ANOl TMI = Three Mile Island ONS = Oconee Nuclear Station CR3 = Crystal River 3 S = Support Plate LTS = Lower Tubesheet UTS = Upper Tubesheet NDD = No Detectable Degradation S/N = Signal to Noise

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Attachment 1 to  !

ICAN099901 Page 4 of13 i

I NRC Question No. 2 l

Proposed TS 4.18.3.a.4 implies that the upper tubesheet area inspection results would not be categorized as either C-1, C-2, or C-3. Provide the basis for excluding these inspection l results from any inspection results classification. Alternatively, Entergy could modify the l TS by incorporating changes similar to those proposed for the proposed license amendment to address steam generator tube end cracking.

Entergy Operations Response The intent of the proposed technical specification (TS) was for previously identified  !

ODIGA that continues to meet the criteria of the ARC to be excluded from categorization. Proposed TS 4.18.3.a.4 has been modified to clarify this intent and to be consistent with the proposed wording for the tube end cracking ARC. Utilizing the revised TS wording, a tube containing newly identified ODIGA would be included in the categorization for the first sample as a degraded tube if it met the ARC criteria for continued service, or as a defective tube if the ARC criteria was not met. If previously 1 identified ODIGA was found to no longer meet the criteria of the ARC, the tube would be I considered defective for categorization with the first sample. Previously existing ODIGA that continued to meet the ARC criteria to remain in service will not be included in the TS categorization. The revised TS page reflecting this clarification is attached.

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P ge 5 of13 NRC Question No. 3 Entergy will measure ODIGA voltages using Plus Point coil eddy current data. The staff notes that measuring IGA voltages using non-oriented, rotating probe coils (e.g., pancake, Plus Point) produces a signal that is highly variable. Provide additional information to demonstrate that consistent voltage measurements of volumetric IGA flaws can be obtained using Plus Point probes.

Entergy Operations Response The Plus Point coil was chosen as the voltage measurement technique for volumetric ODIGA based on its correlation with maximum depth. In order to demonstrate the Plus 4 Point coil's correlation with maximum depth and variability relative to the pancake and oriented coils, a study was conducted. This study included the analysis of six independent 1 acquisitions of nine different laboratory ODIGA defects using the Plus Point, 0.115 inch pancake, and axially wound and circumferentially wound coils. The samples were chosen j to provide a range of depths for the study. The dimensional information can be found in l Table 18 of BAW-10235P, Rev. O. The re-analysis was performed by two analysts using techniques consistent with Revision 5 of the EPRI PWR Steam Generator Examination

]

Guidelines.

The data is summarized by calculating the average voltage and the standard deviation for each sample and each coil utilized as shown in the table below. The numbers in bold italics note the coil that produced the greatest variability for that sample. The data shows that the pancake and circumferentially wound coils have the most variability for the samples evaluated. The data also shows that the standard deviations of the Plus Point voltages are much less than 0.1 volt, and provide an equivalent or higher level of consistency relative to the oriented coils.

TABLE 3-1 EC Variability Average Voltage Voltage Standard Deviation Sample Pancake Plus Point Axial Circ. Pancake Plus Point Axial Circ.

15 0.70 0.51 0.43 0.65 0.11 0.06 0.04 0.02 19 0.18 0.15 0.11 0.18 0.02 0.02 0.02 0.02 i 44 0.34 0.31 0.25 0.43 0.13 0.01 0.07 0.03 l

50 1.21 0.30 0.57 0.78 0.04 0.04 0.03 0.05 i 74 1.20 0.83 0.84 1.00 0.08 0.03 0.03 0.03 107 0.17 0.07 0.09 0.14 0.02 0.02 0.02 0.05 I 113 1.34 0.32 0.51 0.67 0.05 0.02 0.04 0.04 115 0.94 0.37 0.45 0.68 0.02 0.02 0.02 0.03 126 1.39 0.65 -0.72 1.01 0.13 0.06 0.03 0.04 I

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'NRC Question No. 4 j l

The in-situ pressure test sampling plan does not provide the claimed statistical assurance )

levels for leakage from the entire population of ODIGA indications when one tube leaks I during testing. It can be shown that increasing the number of tests in response to identifying a leaking flaw during sampling where it was presumed no indications would j

have leaked does not demonstrate a 95-percent probability that the remaining indications <

in the population will leak less than some specified value. - Provide the basis for using a probability of less than 95 percent in demonstrating that the population of ODIGA indications will leak less than the maximum accident-induced leak rate when the condition monitoring in-situ pressure testing program confirms leakage from at least one ODIGA j indication. Alternatively, Entergy should modify the proposed sampling plan to demonstrate the stated objective.

Entergy Operations Response Ifleaking indications are found in the sample tested, a 95% confidence will be assured for both condition monitoring and assessing operability. The approaches are as follows: 1

1. Condition Monitoring - the total number of samples tested will be utilized to determine the possible number of leaking indications in the population (at a 95% .

confidence level). For example, if 130 indications are found in a steam generator and )

22 indications are tested, resulting in one leaking indication, then it can be said with approximately 95% confidence that not more than 23 potential leaking indications exist in the population (using equation 6 of BAW-10235P, Rev. 0). The 23 largest '

axial extents (from those not tested) plus the leak rate from the leaking indication in the sample size will be summed in order to determine the total leakage from UTS volumetric ODIGA. j

2. Operational Assessment - the sample size will provide a 95% confidence that not more I

than a certain number ofleaking indications exist in the steam generator. The topical report states that the total number of samples to test if one tube leaks during testing is based on changing the in:tial assumption from 0 leaking samples to 1 leaking sample.

This approach will result in testing a sample size that provides at least a 95%

confidence. The reasons are as follows:

• The allowable number ofleaking indications in the population is based on summing the largest indication axial extents (refer to BAW-10235P, Rev. O, Section 8.3.3.1) to be returned to service.

• The in-situ leak tests conservatively target the larger indications for testing.

• If a leaking indication is found in the sample size tested assuming no leaking indications, then more indications will be tested (BAW-10235P, Rev, 0, Section 8.4.5).

1 1

a

,- .- Attachment I to 1CAN099901 Page 7 of13 e By testing more of the large indications, the allowable number of leaking

' indications increases due to the smaller extent sizes of the indications to be returned to service, e The adjustment of the population and allowable number of leaking indications offsets the effect of the 1 leaking indication in the sample. If necessary, the sample size will be increased in order to ensure a 95% confidence.

Table 4-1 shows this in the form of an example. Again, assume 130 indications will be returned to service in a steam generator. Assuming that no leaking indications will be found in the tested sample, 22 indications are tested to provide a 95% confidence (reference column 1). During testing, however,1 leaking indication is found. Ifit were initially assumed that 1 indication would be found to leak, then 35 indications would have been tested rather than 22 (reference column 2). An additional 13 indications will therefore be tested in order to achieve a 95% confidence that not more than 21 indications in the population will leak (reference column 3). The increase in allowable leaking indications is achieved by sampling the' largest axial extents such that the leakage rate based on the 21 largest indications from the reduced population is the same as the leakage rate based on the 15 largest indications from the initial population. In other words, by coordinating the tested sample size and the selection of the samples to test, a 95%

confidence is assured. Alternatively,18 indications could be selected (instead of 13) in order to achieve the 95% confidence (reference column 4) that not more than 15 indications in the population will leak.

TABLE 4-1 j Tested Sample Sizes Initial Test Second Test Sample Assumptions

]

(Due to Leaker in First Sample) j 0 Leakers 1 Leaker Increased Allowable Increased Sample _

Leakers Size Population 130 130 108 108 Confidence 95 % 95 % 95 % 95 %

Probability 0.05 0.05 0.05 0.05 Sample Size 22 35 13 18 Leakers in Samples 0 1 0 0 Leakers in Population 15 15 21 15 Reference Column 1 2 3 4 i

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' NRC Question No. 5  ;

The ODIGA growth criteria will not permit the easy detection of growth if it should actually occur. The bases for this conclusion are as follows: (1) only limited requirements have been proposed that would establish the use of consistent eddy current methods in j each inspection, and (2) no mechanisms exist for detecting growth of individual indications. In addition, the staff notes that a fundamental assumption of this alternate ,

repair criteria is violated if ODIGA indications begin to grow. Nevertheless, Entergy's application proposed continued use of the ARC evenFif ;w 'i was draected. Provide additiond information to the staff that addresses these icsues or modify the proposed

, repair criteria.

Entergy Operations Response The techniques used at ANO-1 have all been qualified or demonstrated equivalent to the EPRI PWR Steam Generator Examination Guidelines: Rev. 5. An independent review of the ANO-1 eddy current analysis guidelines is also required to ensure applicability to the

- damage mechanisms and conditions found in the ANO-1 steam generators. Only 1 personnel that have successfully completed the Qualified Data Analyst training and testing  !

program in accordance with the requirements of Rev. 5 of the EPRI Guidelines are l allowed to analyze data at ANO-1.

Part of the ANO-1 analysis guidelines contains material that is used as the basis for the

'ANO-1 analysis training manual. Prior to each outage the analysts are trained on the damage mechanisms associated with OTSGs in general and those found at ANO-1 receive special emphasis (e.g. upper tubesheet IGA). A select group of analysts will perform the sizing (length, width, and volts) required by the ARC. Using a small set of analysts

reduces the measurement uncertainty. The analysts performing the sizing receive additional instruction in locating and sizing the upper tubesheet IGA indications.  ;

Each analyst must pass a site specific performance demonstration examination before being allowed to analyze ANO-1 data. To further ensure that indications are sized in a repeatable manner, only analysts that have performed this function previously, either at ANO-1 or another plant, are allowed to size the IGA indications at ANO-1.

Calibration standards that will be used during the IR15 inspection have been fabricated in accordance with the requirements of Rev. 5 of the EPRI Guidelines. These standards have been compared to a mother standard stored at the Framatome offices in Lynchburg, VA to ensure that voltage measurements are consistent between examinations.

The information above will be included in the topical report.

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Attachment I ts 1CAN099901 Page 9 of13 j GrmRh ofIndyklualFlaw

s. The growth'of the IGA' flaws will be evaluated cu an indicetion specific basis. This is

accomplished using two criteria, which are being inco porated ir.m the' topical repo t.

. ladvhinalflaw-Criterion 1 Three flaw parameters (length, width, and Plus Point volts) will be obtained during each inspection for each UTS ODIGA indication. The parameters will be compared to the

. previous values (two outages if available) and greatest " change" value obtained. This change value will be added to the value recorded during the outage and compared to a-

- repair limit.'

The limit for axial and circumferential extent is 0.5" and is based on testing described in i the topical report;' The limit for the plus-point amplitude is 1.14 volt which is based on

. previous in-situ testing and results from the repeatability study. The largest flaw in-situ tested as' measured by Plus Point was 1.26 volts. The 1.14 volt value is derived from

subtracting two times the largest standud deviation observed in the study presented in the ' 1 response to the request for additional information (RAI) Question 3 (2 x 0.06) from the

.1.26 volt value.

The following example is how the three parameter comparison under criteria 1 is implemented.

A.) Axialextent:

1 Two inspections prior (if available) - axial length measurement = 0.2" Previous inspection - axial length measurement .= 0.3" Current inspection axiallength measurement = 0.3" f

Largest delta observed = 0.1" 0.3" + 0.1". = 0.4" which is less than 0.5" => flaw meets the limit at the end of cycle (EOC).

B.) Circ extent: J Two inspections prior (if available) - circumferential extent measurement = 0.25"

- Previous inspection - circumferential extent measurement = 0.3" Current inspection - circoo.ferential extent measurement = 0.3" Largest delta observed = 0.05"

. 0.3" + 0.'05" = 0.35" which is less than 0.5" => flaw meets the limit at EOC l

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C.) Plus Point volts:

Two inspections prior (if wailable) = 1.0 volt Previous inspection = 1 volts e Current inspection = 1.2 volts Largest delta observed = 0.2 volt 1.2 volts + 0.2 volt = 1.4 volts which exceeds the limit and requires the tube to be repaired.

This approach considers all three parameters with any one of the three limits being exceeded requiring repair.

Individualflaws- Criterion 2 The 95% upper tolerance limit (UTL) will be obtained for each of the three-parameter distributions. This value will be added to the parameter value obtained during the inspection and compared to the repair limits as mentioned above. As with Criterion 1, any one limit being exceeded will require repair.

The following example is how me amparison under Criterion 2 is implemented A.) Axial extent:

Two inspections prior to current inspection (if available) delta distribution 95%UTL =

0.025" Previous inspection to current inspection delta distribution 95%UTL = 0.05" Current inspection measurement = 0.3" 0.3" + 0.05" = 0.35" which is less than 0.5" => flaw meets the limit at EOC.

B.) Cire extent:

Two inspections prior to current inspection (if available) delta distribution 95%UTL =

0.05" Previous inspection to current inspection delta distribution 95%UTL = 0.1" Current inspection measurement = 0.3" 0.3" + 0.1" = 0.4" which is less than 0.5" => flaw meets the limit at EOC.

C.) Plus Point volts:

Two inspections prior to current inspection (if available) delta distribution 95%UTL =

0.20 volt Previous inspection to current inspection delta distribution 95%UTL = 0.10 volt Current inspection measurement = 0.90 volt

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Attachment 1 to ICAN099901

. Page 11 of13 0.90 volt + 0.20 volt = 1.10 volts which is less than 1.14 volts => flaw meets the limit at EOC.*'

In this case the flaw meets all three of the limits in Criterion 2. The flaw must meet both

~ Criterion 1 and Criterion 2 in order to be left in service.

OmallPopuladon Growth The ODIGA growth will. be monitored by evaluating relative increases in the mean population of change in length, circumferential extent, and Plus Point volts as described in the topical report. If two of the three parameters indicate growth then the ARC can not be applied and all tubes containing ODIGA will be repaired. The growth assessment is described in the topical report.

Discussion of Changes to Proposed Technical Specifications The responses to the RAI have necessitated several revisions to the proposed TSs for the ODIGA ARC originally submitted on May 14,1999 (ICAN059901). Several other clarifications have also been proposed based upon' discussions with the staff and Entergy personnel. The proposed changes are discussed below:

• References to tcpical report BAW-10235P, Rev. O have been replaced with BAW-10235P, Rev.1. The topical report has been revised in several sections in response to the RAI. The affected TSs are 4.18.3.a.4,4.18.5.a.7, and the Bases section.

• In response to RAI Question 2, proposed TS 4.18.3.a.4 has been revised by deleting the sentence that would have excluded the results of the ODIGA inspection from categorization with the first sample. This sentence has been replaced by one that excludes only previously identified ODIGA that continues to meet the criteria

. of the ARC from categorization. ,

• The last sentence in the definition of Plugging Limit, TS 4.18.5.a.7, han been revised by changing the word " imperfections" to " indications." This clarif cation was made because an imperfection is defined as being less than 20% throug h-wall in TS 4.18.5.a.2. The ODIGA indications included in the ARC are not depth

' sized. This clarification has also been made in the Bases.

• The summary of the operational assessment to be reported to the NRC by TS 4.18.6.e was clarified to include discussions on observed growth of ODIGA

. indications.

Since the changes to proposed TSs provide either clarifications or more conservative criteria' for utilizing the ARC, the no significant hazards consideration and

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' 1CAN099901 -

Page 12 of13 environmental impact evaluation included in Entergy's May i 4,1999 submittal remain boundihg. ' The revised TS pages are attached.

. Discussion of Changes to BAW-19235P, Rev. 0 The responses'to the RAI have necessitated m:versi enanges to the topical report for the ODIGA 1 ARC - (BAW-10235P, Rev.0) originally submitted on May 14, 1999

- (ICAN0599@l). Revision 1 to the topical report will incorporate these changes. The revision to the topical report will be submitted by September 10,1999. Proposed changes to the top' cal report nr6 summarized below:

Section 7.1 Added a scence stating growth will be evaluated by comparing both the overall population and individual flaws.

Section 7.1.2 Clarified that this section discusses the growth monitoring pocedure fbr the overall population.- Added that the growth will be mu.4ored Li two phases (individual tubes and overall population of ODIGA).

Section 7 l.2 In the paragraph below STEP 4: added "and the. ARC will not be applied'~

after assumed.

Section 7.1.3 Added a new section (7,1.3) for the overall population approach and a section (7.1.4) for the individual flaw growth. Included example information from the response to RAI Question 5.

Section 7.1.3 In the old section 7.1.3 (new 7.1.5), clarified that this discussion is for the overall population.

Section 7.2 - Added information to further describe the POD curve.

. Section 7.3 - Added that new indications should be compared on a per flaw basis (i.e.

95% UTL + current measurement).

Section 8.2 - Add information on reliability as discussed in the response to RAI Question

.3.

Section 8.3 Added information clarifying that a 95% confidence level will be obtained as discussed in the response to RAI Question 4.

Section 8.3.1' 1" paragraph, Deleted the last sentence and added "and the ARC can not be applied".

Section 8.3.2 L Removed info about crediting previous in-situ testing if population growth 1 6 exists.

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- 1CAN099901 Page 13 cf13 1 Sectidn' 8.3.5 Added information for reporting the growth assessment.

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