3F0805-06, Attachment F, Crystal River Unit 3 - License Amendment Request 290, Revision 1, Addendum C, 08/12/2005 to Topical Report 2346P, Revision 0
| ML052440192 | |
| Person / Time | |
|---|---|
| Site: | Crystal River  |
| Issue date: | 08/12/2005 |
| From: | Progress Energy Florida |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| 3F0805-06 BAW-2346P, Rev 0 | |
| Download: ML052440192 (14) | |
Text
PROGRESS ENERGY FLORIDA, INC.
CRYSTAL RIVER UNIT 3 DOCKET NUMBER 50-302/LICENSE NUMBER DPR-72 ATTACHMENT F LICENSE AMENDMENT REQUEST #290, REVISION 1 Addendum C Dated August 12,2005 to Topical Report 2346P, Revision 0
Crystal Unit 3 LAR # 290 Addendum C to Topical Report BAW-2346P Rev 0 EC 61937 Rev 0 Dated 8/12/05 Page 1 of 7
CR3 OTSG Tube End Crack (TEC) Leakage Proiections This document provides the basis for future projection method for axial Tube End Crack (TEC) indication MSLB accident induced leakage at Crystal River Unit 3. These projections will be used to determine the projected TEC leakage for the next OTSG inspection in conjunction with NRC approved LAR # 290 or existing leak rates to determine the required tube repairs (plugging or re-rolling) to be performed during an outage to address the TEC Alternate Repair Criteria (ARC). The projections will also provide input to the Operational Assessment (OA) upon conclusion of an outage. This method will demonstrate a conservative approach to TEC leakage predictions based on the current CR3 TEC trends.
Inputs/Assumptions:
- a.
The described method satisfies the minimum requirements for calculating the projected TEC leakage contained in BAW-2346P Rev 0 as required by ITS 5.6.2.10.2.f.
- b.
TEC leakage rates based on the methodology in Framatome calculation 51-5053331-01 (Ref 3) and 32-5053981-00 (Ref 4) may be used IF the NRC has approved Licensing Amendment Request (LAR) # 290. These leak rates are based on a probabilistic calculation approach. The LAR method provides an alternate method of determining TEC leak rates vs. tubesheet radius that is expected to result in more realistic, but still conservative, TEC leak rates. These leak rates are determined by a Framatome developed software program called LeakTEC using a 95/95 Monte Carlo statistical method.
- c.
This method meets the intent of the EPRI Steam Generator Integrity Assessment Guideline (Ref 5) and NEI 97-06 (Ref 7) for determining the projected (OA) TEC leakage for the limiting OTSG accident conditions.
- d.
TEC leakage instead of numbers of indications is used for this projection method. Leakage is used since it is identified as a maximum postulated leak rate and is the ITS 5.6.2.10.2.f administrative limit for TEC's. There is no limitation on the number of TEC indications as long as the postulated leakage limits in ITS 5.6.2.10.2.f are satisfied.
- e.
Examples of leak rate numbers in this evaluation use typical leakage rates from Ref 1. The corresponding leakage using the LAR # 290 method will be significantly lower.
Page 2 of 7
CR3 OTSG ACCIDENT-INDUCED (MSLB) PRIMARY-TO-SECONDARY LEAKAGE LIMITS SIMPLIFIED DIAGRAM (PER OTSG)
Figure 1 1.0 GPM Pri-to-Sec FSAR
& NEI 97-06 leakage assumption iL
}
ll 150 GPD (corrected for accident conditions)
Il r.
11 0.856 GPM ITS 5.6.2.10.2.f Admin Limit based on Ref 6 II I
The total for TEC & all Other Leakage must be < 0.856 GPM
[
Projected leakage from all other OTSG
}
l degradation mechanisms besides TECs 1H L
iJ TEC Probability of Detection (POD)
J 1Leakage -Margin 1
} [l Projected TEC leakage increase from previous cycle, if applicable 1~
l "Neag" TEC Leak-age Total Projected TEC Leakage Baseline = 0 lGPM l
}
lAs-Left TEC Leakage J
Page 3 of 7
CR3 TEC Leakage Proiection Model PL-ALTEC Leakage + PODLeakage + NLeakage + AddLeakage PL= Total Projected Leakage ALmEC ckabg = As-Left TEC Leakage from the current inspection (Note 1)
PODLeaahg = The current inspection As-Found Leakage divided by 0.84 minus the current inspection As-found leakage (i.e.,
(0.7/0.84) - 0.7) (Note 2)
Niacage= New Leakage - Current As-Found TEC Leakage minus the Previous As-Left TEC Leakage (Note 3)
AddLe,,kag = Additional leakage based on trending (Note 4).
Note 1 -
As-Left TEC Leakage includes the total of all radial zone tubes including both upper and lower tube end indications. This includes all tubes with TEC indications identified during an inspection that are not repaired prior to closing out the OTSG.
Note 2 - Use equation for POD from BAW-2346P Rev 0. This can be calculated by the following equation example: [As-found total TEC leakage/0.84* - As-found total TEC leakage]; [(0.7/0.84) - 0.7] = 0.133 gpm.
Note 3 -
New TEC Leakage is the amount of total TEC leakage detected (as-found) above the amount left in service from the previous inspection. For example: 14RAs-Fou.d IEC Leakage - 13Rm.Lfe TEc Ltakge) equals the "New" TEC Leakage for one operating cycle. This is done for both upper and lower tube ends. This amount includes the TEC indications/leakage that were either not detected in previous outages or developed during the previous operating cycle. The assumption is that the new TECs that were identified in the previous operating cycle represent a similar trend of what future cycle "new" TEC leakage will be.
Note 4 - To account for a TEC increasing leakage trend, an additional amount of TEC leakage needs to be added above the previous cycle "new" TEC leakage IF there is any recent increasing new leakage trend. The use of a linear extrapolation method using the changes in New TEC leakage was selected as the way to project potential increases in the TEC leak rates.
See Enclosure 1 for a description of why this method was chosen. Linear extrapolation involves comparing the "new" TEC leakage from the previous two operating cycles. For example, determine the 14R As-found EC leakage - 13R As-keftC Leakage new TEC leakage and compare to the 13R A-found TEC leakage - 12R As-lCeft TEC Leakage) new TEC leakage. If the most recent operating cycle "new" TEC leakage is less than the previous "new" TEC leakage, then there is no apparent increase and this amount is 0.0 gpm. This means that a decreasing trend cannot be used to provide a leakage credit.
However, if the most recent operating cycle "new" TEC leakage is greater than the previous "new" TEC leakage, than the leakage difference between the two operating cycles should be added to the projection. As examples, if the 13R new leakage was 0.45 gpm and the 14R new leakage is 0.45 gpm than no increasing leakage trend is apparent and no additional leakage amount is applied to this parameter. Conversely, if the 13R new leakage was 0.40 gpm and the 14R new leakage is 0.45 gpm than an increasing trend may be developing. In this case, an additional leakage amount of 0.05 gpm (0.45 - 0.40) should be added to the projected leakage. The equation for this process is (14RDCW leakage - 13R,
eIcahg) = Increase Leakage Amount.
To account for the possibility of a continuously increasing trend that deviates from the expected steady or decreasing growth rates observed in Figure 2, also compare the new leakage values for the 12R new and 13R new leakages. If the new leakage from 13R was greater than the new leakage from 12R, then determine that difference. If the 13R-14R increase is larger than Page 4 of 7
the 12R-13R increase, then an increasing rate trend may be occurring. In this case, an additional amount will be added to the 13R-14R extrapolated amount. This overall process can be summarized by:
- 1. If there is no increasing trend between the 12Rnmw to 13R,,w to 14R,,,, then there is no increasing trend and the Increasing Leakage is 0.0 GPM.
- 2. If there is an increasing trend only from 12R1ew to 13Rn¢,w but not for 13R1,, to 14R,,,,. then there is no increasing trend and the Increasing Leakage is 0.0 GPM.
- 3. If there is an increasing trend only from 13R,,, to 14Rnew, then the Increase Leakage is determined by: Increasing Leakage = (14R,,,w - 13Rn,).
- 4.
If the last two cycles show an increase in new leakage and the most recent increase is less than the previous increase, then Increase Leakage is determined by: Increasing Leakage = (14Rnew - 13R,,,).
- 5.
If the last two cycles show an increase in new leakage and the most recent increase is greater than the previous increase, then Increasing Leakage is determined by: (14Rnew - 13Rn,,) + [(14Rnew -
13Rnew) - (13Rnew -
12Rncw)] =
Increasing Leakage.
Overall Acceptance Criteria:
Total Proiected TEC Leakage + All Other Degradation Leakage (Roll Transitions, Non-tube end degradation, etc) must be <1 GPM-150 GPD (0.856 GPM) Prior to OTSG Closeout Or Reroll/Plug (Repair) as necessary in the current outage to get the total projected TEC leakage & other degradation for next outage below 0.856 GPM EXAMPLE (Note - These are example numbers only)
As an example of how the overall calculation is performed, see the following:
As-Left TEC Leakage from 13R = 0.325 gpm 1 IR to 12R New TEC Leakage = 0.360 gpm 12R to 13R New TEC Leakage = 0.350 gpm As-Found TEC Leakage for 14R = 0.7 gpm POD Leakage for 14R = [(0.7/0.84) - 0.7] = 0.133 gpm New Leakage for previous Cycle = (0.7 - 0.325) = 0.375 gpm
- Additional Leakage Trend [(13R to 14R new) - (12R to 13R new)] = [(0.375 gpm) - (0.350 gpm)] = 0.025 gpm Total of "Other" OTSG Leakage = 0.06 gpm from the Operational Assessment Page 5 of 7
If no repairs are initially performed, the as-left TEC leakage will be the same as the as-found TEC leakage. Therefore, projected TEC leakage =
As-Left 14R TEC Leakage = 0.7 gpm
+
Change (New) 14R TEC Leakage = 0.375 gpm
+
Undetected Indication POD Leakage = 0.133 gpm
+
Increasing Trend TEC Leakage (applicable in this case) = 0.025 gpm
= Proiected TEC Leakage = 1.233 gpm Combined with 0.06 gpm for the "Other" OTSG degradation the total projected leakage = 1.293gpm Since the 1.293 gpm total is greater than the 0.856 administrative ITS limit, some the as-found TEC indications/leakage must be removed from service before returning the OTSG to service. Therefore, the as-found TEC leakage must be reduced by at least (1.293 gpm - 0.856 gpm) 0.437 gpm.
The as-left TEC leakage must be reduced to at least 0.7 gpm - 0.437 gpm =
0.263 gpm. This means that repairs must be completed on the existing as-found TEC indications to result in an as-left TEC total of < 0.263 gpm.
References:
- 1. BAW-2346P Rev 0, Dated 04/99, Alternate Repair Criteria for Tube End Cracking in the Tube-to-Tubesheet Roll Joint of Once Through Steam Generators
- 3. Framatome Calculation 51-5053331-01, Rev 1, Dated 8/10/05, Probabilistic Leakage Assessment of Crystal River Unit 3 SG Tube End Cracks
- 4.
Framatome Calculation 32-5053981-00, Rev 0, Dated 12/2004, Probabilistic Implementation of CR-3 TEC ARC-Supporting Calculations
- 5.
EPRI Report TR-107621-R1, Dated 03/00, Steam Generator Integrity Assessment Guidelines
- 6.
Framatome Calculation 32-5035732-00, Rev 0, Dated 01/04, CR3 RFO-13 TEC ARC Leakage Calculation
- 7.
NEI 97-06 Rev 1, Steam Generator Program Guidelines, Dated 12/1999 Page 6 of 7 The method for projecting future TEC leakage to account for possible increasing rates was based on having a limited number of historical data points available while still providing conservative projections. To date (thru 13R), there are only two data points (I1iR - 12R & 12R - 13R) for new TEC leakage because the TEC ARC has only been in effect since the 1999 (1 1R) outage. We have the new leakage that developed from 1 iR to 12R and the new leakage that developed from 12R to 13R. If the overall leakage is increasing, a linear projection assumes that it will continue to increase at the same rate. CR3 plant data in Figure 2 shows that the increase in cumulative number of tubes with TEC upper indications is actually slowing down. (i.e.
The cumulative number of indications continues to go up over time, but at a slower rate). Note - Lower TEC tubes are not included in the graph because there is only one data point in 13R. Some of the decrease may be due to the fact that as tube ends are rerolled or plugged, the total population of available tubes is decreasing. This would indicate that the change in total leakage rate should also be steady or decreasing. This is supported by the most recent data from 13R where 11 out of the 12 radial zones showed either no change or a decrease in percent of tubes with new TECs (Reference Letter 3F0505-12 Attachment D Response b.vii.to NRC) from 12R to 13R.
Various curve fit projections were evaluated for predicting increasing TEC leakage rates. The low number of data points restricts the use of many of the typically used methods. By extrapolating the increase between the two previous cycles to 15R, the linear extrapolation method (not to be less than the 14R new leakage) was the most conservative. Therefore, the linear extrapolation method will be used based on the readings for new leakage.
CR3 Number of Upper Tube Ends with TEC Figure 2 1800 100 ILu I-s 1600 -*_VY I 1400 s 1200 1000 o800 E
600 z
400 E
200 0
0 I_l11 IIl1l 1 11.5 12 12.5 13 13.5 14 14.5 15 15.5 16 16.5 17 17.5 18 18.5 19 19.5 (Mid-(1999)
(2001)
(2003)
(2005 Cycle Curve Pre-Fit)
ARC)
EFPY A OTSG Axial Upper Tube End Crack Tubes Log. (B Axial Upper Tube End Crack Tubes )
B Axial Upper Tube End Crack Tubes
- Log. (A OTSG Axial Upper Tube End Crack Tubes) c OI Page 7 of 7
PROGRESS ENERGY FLORIDA, INC.
CRYSTAL RIVER UNIT 3 DOCKET NUMBER 50-302/LICENSE NUMBER DPR-72 ATTACHMENT G LICENSE AMENDMENT REQUEST #290, REVISION 1 Response to NRC Request for Additional Information (RAI)
Regarding License Amendment Request #290, Revision 0
U.S. Nuclear Regulatory Commission Attachment G 3F0805-06 Page 1 of 5 NRC Ouestion
- 1. In your January 27, 2005, submittal, you proposed to modify the portion of the accident induced leakage methodology associated with implementation of the tube end cracking (TEC) alternate repair criteria. The TEC accident induced leakage methodology involves two parts:
(1) projecting the number of TEC indications and (2) assigning a leakage value to each TEC indication. Your January 27, 2005 proposal involves changing the portion of the methodology for assigning a leakage value to each TEC indication to make it less conservative.
As discussed in Licensee Event Report 50-302/2004-004-00 dated November 22, 2004 (ML043340228), you exceeded your accident induced leakage limit during your 2003 refueling outage (designated 13R). One of the primary reasons for this occurrence was that you did not conservatively project the number of TEC indications Furthermore, in your letter dated May 20, 2005, you indicated that part of your corrective action to ensure the leakage limit would not be exceeded included your January 27, 2005 license amendment request.
Although your license amendment request may result in lower amounts of accident induced leakage, it does not address the fundamental cause of exceeding the accident induced leakage limit during several of your previous outages (i.e., the under prediction in the number of indications detected during the outage). As a result, please provide the method to be used to ensure that the number of TEC indications will be conservatively projected in all future outages for NRC review and approval. We suggest that this methodology and its technical justification be submitted as Addendum C to BAW-2346. (Section 7.2 of the submittal appears to discuss three new potential approaches for accounting for new indications which may occur during the operating cycle. However, Section 7.2 does not specifically commit to performing any of these three approaches. In addition, the description of each of these approaches would need to be amplified such as to provide a complete description of the approach.
- Finally, Section 7.2 lacks a technical rationale for why any of these approaches will yield a conservative estimate of the number of TEC indications which will exist at the end of the next cycle. For example, had these approaches been implemented in past cycles, how would the projected number of indications at the next end of cycle have compared to what was actually found?)
Response
Framatome-ANP document 51-5053331-00 (Probabilistic Leakage Methodology of Crystal River Unit 3 SG Tube End Cracks) provided as Addendum B (Attachment E of this submittal) has been revised to exclude Section 7.2 as well as any references to those potential approaches for accounting for new TEC indications.
The Framatome-ANP document no longer identifies any method to projecting TEC indications or leakage.
Crystal River Unit 3 (CR-3) has instead developed a method to account for future TEC leakage that uses plant specific historical leakage rates using data from the refueling 1IR (1999), 12R (2001), and 13R (2003) outage inspections. This method is described in Addendum C to BAW-2346P Rev 0 which is being submitted in this letter (Attachment F). Existing leakage trends show that the number of new as-found tubes with TEC indications has not changed significantly in the previous two cycles and therefore the use of historical data is used to help predict future leakage. Predicted TEC leakage includes separate components for determining the as-left leakage, new leakage, POD leakage, and an increased leak rate amount if increasing trends are detected.
These leakage components are combined to produce the predicted TEC leakage per steam generator. This method was selected
U.S. Nuclear Regulatory Commission Attachment G 3F0805-06 Page 2 of 5 because it can be shown to provide realistic, but still conservative leakage projections. This method will continue to meet the Topical Report BAW-2346P Revision 0, assumptions for the Alternate Repair Criteria (ARC).
A prediction methodology used by the Diablo Canyon plant called POPCD (Probability of Prior Cycle Detection) was also reviewed as a possible prediction method for CR-3. At other plants, POPCD is used along with bobbin probe examinations to adjust the bobbin POD instead of using a more accurate rotating coil probe. CR-3 already uses a rotating coil probe to examine the tube ends.
Our OTSG eddy-current and engineering evaluation vendor Framatome-ANP also determined that the POPCD method was not a good fit for the TEC degradation mechanism at CR-3. The lack of OTSG industry plant data on TECs also made it difficult to provide an adequate basis for using POPCD or any other method.
The CR-3 proposed method was used to benchmark against a previous cycle of known TEC leak data. The data below represents the use of this method if it had been used in the 12R (2001) refueling outage to predict the 13R (2003) TEC leakage. The data from 12R shown below contains data that has no "Increase" leakage value because there was insufficient data from prior outages to have a trend. In all future outages, the increase leakage component will be no less than zero and will be greater if the trend is upward. This means that when this method is used in the 14R, and beyond, the predicted leakage will be at least if not more conservative than the 13R predicted values presented here.
A OTSG Predicted TEC Leakage for 13R B OTSG Predicted TEC Leakage for 13R As-Left for 12R 0.625 GPM As-Left for 12R 0.625 GPM New (12R - 11R) 0.336 GPM New (12R - 1 IR) 0.442 GPM POD 0.120 GPM POD 0.169 GPM Increase Trend N/A - No prior cycle Increase Trend N/A - No prior cycle data data Total =
1.081 GPM Total =
1.236 GPM A OTSG Actual TEC Leakage for 13R B OTSG Actual TEC Leakage for 13R As-Found 13R Upper 0.932 GPM As-Found 13R Upper 1.102 GPM As-Found 13R Lower 0.013 GPM As-Found 13R Lower
- 0. 124 GPM Actual 13R Total =
0.945 GPM Actual 13R Total =
1.226 GPM
==
Conclusion:==
The predicted TEC leakage for both steam generators over-predicted the actual A-OTSG uppe TEC leakage by - 16% and - 12% in B-OTSG. The first of-a-kind lower TECs were not expected in 13R, but there was still sufficient margin to address that increase.
NRC Ouestion
- 2. The assumed axial loading for main steam line break (MSLB) is 663 lbs max. Does this load correspond to the specific MSLB considered in the FSAR accident analyses? Are descriptions of the supporting thermal-hydraulic and structural analyses for this load on the docket and, if so, where? Has the thermal-hydraulic analysis been reviewed and approved by the staff?
U.S. Nuclear Regulatory Commission Attachment G 3F0805-06 Page 3 of 5
Response
The 663 lb tube load is based on CR-3 specific analyses documented in proprietary Topical Report BAW-10164P, "RELAP5/MOD2-B&W-An Advanced Computer Program for Light Water Reactor LOCA and Non-LOCA Transient Analysis," Revision V, November 1998 [Referenced in Chapter 14 of the CR-3 FSAR (Submitted to the NRC by Babcock and Wilcox Co. on November 11, 1980, Accession Number 8011180258] and Framatome ANP proprietary document "OTSG Transient Analysis", Appendix M (CR-3 Plant Specific MSLB), Revision 5, October 1999. The descriptions of the thermal-hydraulic and structural analyses for this load are not in the CR-3 docket, but the results were previously reviewed and accepted as part of License Amendment No. 188 (Table 2 of License Amendment Request #249, Revision 0, Once Through Steam Generator Tube Surveillance Program (TAC No. MA5395), Addendum to Babcock & Wilcox Owners Group Topical Report BAW-2346P dated May 28, 1999).
The Chapter 14 MSLB scenario provided the boundary conditions for the calculation of the tube loads. Note that CR-3 tube loads are smaller than the generic tube loads calculated in the past (BAW-10146P, Determination of Minimum Tube wall Thickness for 177 FA Once Through Steam Generators dated October 1980, Referenced in Chapter 14 of the CR-3 FSAR). This is attributable to differences in system hardware, their response to transient conditions and more advanced analytical methods (i.e. ANSYS, RELAP).
NRC Ouestion
- 3. Tables 6-1 and 6-2 in Attachment A of the licensee's January 27, 2005 submittal purport to benchmark the probabilistic approach (LeakTEC) with the deterministic approach for performing condition monitoring and operational assessment.
These Tables suggest the probabilistic approach reduces the leakage estimates by roughly 2/3 compared to the reference deterministic approach. However, whereas the leakage versus delta dilation (or tubesheet radius) data used in the probabilistic analysis had been adjusted to reflect the change in tube diameter associated with the Crystal River 663 lb (max.) axial load, the deterministic approach utilized leakage data reflecting a change in tube diameter associated with a 3060 lb (max.) axial load. In addition, the deterministic method considered conservative step functions for the leak rate versus delta dilation and tubesheet radius relationships rather than more realistic smooth relationships. What is the effect on the deterministic results in Tables 6-1 and 6-2 if the leakage data upon which they are based are revised to reflect the tube diameter change associated with the Crystal River 663 lb (max.) axial load and if the leakage versus delta dilation and tubesheet radius relationships utilized were based on continuous curves (developed by interpolation) rather than conservative step functions?
Response
Additional deterministic leakage estimates have been developed to reflect the effects discussed in RAI #3 and Addendum B (Attachment E) has been revised to include the information in Tables 6-1 and 6-2. The results of this work reveal that the elimination of tubesheet zones in favor of a continuous approach reduced the End of Cycle 13 (EOC13) estimate of total leakage returned to service by 12% to 15% as compared with deterministic estimates documented in the Condition Monitoring/Operational Assessment (CMOA).
Accounting for the affect of axial load on delta dilation in the leak test data further reduced this estimate by an additional 45%. Removal of both of these sources of conservatism from the deterministic leakage calculation methodology yields results
U.S. Nuclear Regulatory Commission Attachment G 3F0805-06 Page 4 of 5 which, in a number of cases, fall below the probabilistic estimates. All estimates except for those documented in the CMOA are based upon CR-3 delta dilation values which include the effect of axial load on tube dilation. However, as illustrated in Addendum B, Figures 3-2 and 3-3 this has a negligible affect on the delta dilation values due to the relatively low axial loads present during the MSLB.
NRC Ouestion
- 4. The second sentence of the fourth paragraph of page 15 of 24 includes 'maximum crack voltage' as an input parameter to LeakTEC. How is this parameter used in the analyses?
Also, in item 2c on page 21 of 24 states that a non-zero value for voltage threshold may only be used if approved by the utility and/or NRC. The staff believes this statement is incorrect and that NRC approval is required in order to use a non-zero voltage threshold value. Item 2c should be clarified accordingly.
Response
The voltage threshold parameter is not used in the analyses methodology submitted for approval in LAR #290. It was provided in the LeakTEC spreadsheet as a feature for possible future application but would only be used with specific NRC approval. Approval is not being sought for the use of this feature in LAR #290. Addendum B (Attachment E) has been revised to affirm that this feature is not to be used without NRC approval.
NRC Ouestion
- 5. The first sentence of the last paragraph on page 18 of 24 states, aFor example, if POD is 0.84, a tube...' Item 2b on page 21of 24 states, 'If "Operational Assessment" was selected, specify the POD value.'
Table 6-3 on page 20 of 24 reports LeakTEC results for cases where POD is assumed to be 0.84 and 1.0, respectively.
These sentences and any similar sentences in the report should be clarified to indicate that 0.84 is the NRC approved value for operational assessments.
Response
Addendum B (Attachment E) has been revised to affirm that the NRC approved value of POD for estimating the quantity of undetected TEC leakage is 0.84.
A POD value of 1.0 is used in conjunction with the LeakTEC "Operational Assessment" only when an estimate of the known return to service leakage is needed (i.e., leakage from TECs that are not repaired). The POD value of "1.0" is only a mathematical means of calculating the "known return to service" part of the total return to service leakage. Specifically, LeakTEC calculates the total return to service leakage as the sum of the undetected leakage plus the known return to service leakage, (TotalRTS = Undetected +
KnownRTS). The "Undetected" part of the leakage equals the "AsFound/POD - AsFound". When using a POD value of 0.84, the "Undetected" leakage equals AsFound*(1/0.84 -
- 1) or
-0.19*AsFound. When using a POD value of 1.0 however, the "Undetected" part of the leakage equals AsFound*(1/1 - 1) or zero thus yielding only the "KnownRTS part of the leakage". The "KnownRTS" leakage is the "AsFound leakage minus the Repaired leakage" This concept has also been clarified within Ref. 1, Table 6-3.
U.S. Nuclear Regulatory Commission Attachment G 3F0805-06 Page 5 of 5 NRC Question
- 6. Step 6 on page 17 of 24 should be corrected to state, aSteps 1 through 5 are repeated..2'
Response
Addendum B (Attachment E) has been revised to correct this error.
NRC Question
- 7. Section 1, "Introduction," (page 4 of 24) states that the report documents an... approach to determine 95%195% accident leakage rates for Crystal River Unit 3 tube end cracks.
However, Step 6 on page 17 of 24 cites the one sided upper 95% probability/95% confidence value of leakage as 'an example" of a desired probability and confidence value. Table 6-3 on page 20 of 24 adds further confusion on the desired probability and confidence value by showing LeakTEC results @ 50/50, 95/50, and 95/95. Please clarify Step 6 on page 17 of 24 and Table 6-3 on page 20 of 24 that the desired probability and confidence value for evaluating leakage against the accident leakage performance criteria (i.e., acceptance limit) is the one sided upper 95% probability/95% confidence value.
Response
Addendum B (Attachment E) has been revised to correct this error.
NRC Question
- 8. The Crystal River technical specifications references BAW-2346P, Rev 0, as providing the methodology for leaving tubes with TEC in service. BAW-2346P, Rev 0, as reviewed and approved by the NRC, does not include Addendum B which is the subject of the licensee's January 27, 2005, LAR #290, Rev. 0, nor does it include an Addendum C which the staff recommended be submitted in item 1 above. Addendums B and C would effectively change the methodology in BAW-2346P, Rev 0. Accordingly, the licensee should submit a technical specification amendment to reference BAW-2346P, Revision 1, rather than Revision 0. The licensee should state in the amendment request that Revision 1 incorporates Addenda B and C.
Response
LAR #290, Revision 1 provided in this submittal proposes to incorporate CR-3 specific Addenda B and C to BAW-2346P, Revision 0 into CR-3 Improved Technical Specification (ITS) 5.6.2.10.2.f.
CR-3 has discussed with the NRC staff the proposed addition of these new requirements (Addenda B and C) without a Revision to BAW-2346P.