ML20012G453
| ML20012G453 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 02/24/1993 |
| From: | Yelverton J ENTERGY OPERATIONS, INC. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20012G454 | List: |
| References | |
| 2CAN029305, 2CAN29305, NUDOCS 9303020474 | |
| Download: ML20012G453 (13) | |
Text
{{#Wiki_filter:. Entergy operationa, Inc. 9 ENTERGY O2%i W 5019%8Ea3 Jerry W. Yelverton l Vcc Rc9 h owwc no February 24, 1993 2CAN029305 U. S. Nuclear Regulatory Commission Document Control Desk Mail Station F1-137 Washington, DC 20555 *
Subject:
Arkansas Nuclear One - Unit 2 Docket No. 50-368 , License No. NPF-6 - Proposed ANO-2 Technical Specification to Revise Containment Internal Pressure Gentlemen: Attached for your review and approval is an updated Large Break Loss of ; Coolant Accident (LBLOCA) evaluation and the associated proposed Technical Specification (TS) change for Arkansas Nuclear One, Unit 2 (ANO-2). This change will revise the containment internal pressure lower '! limit of TS Figure 3.6-1. , The new LBLOCA evaluation is performed utilizing the latest approved l ABB-CE evaluation model which is in accordance with 10CFR50 Appendix K. This methodology has been used by other Combustion Engineering plants , (Waterford-3, St. Lucie, and Calvert Cliffs). The new LBLOCA analysis ( also allows for up to 10% steam generator tube plugging. In accordance with 10CFR50.91(a)(1), and using criteria in 10CFR50.92(c), ; Operations has determined that this change involves no ! Entergy significant hazards consideration. The bases for these determinctions : are included in the enclosed submittal. Although the circumstances of this submittal are neither emergency or exigent, prompt review and approval of this proposed amendment is requested. We request that the effective date of this change be 30 days ! after NRC issuance of the amendment to allow for distribution and Implementation of procedure revisions. Very truly yours, 1
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J. W. Yelverton i 1 010140 JWY/jt Attachments 9303020474 930224 i'
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U. S. NRC February 24, 1993 j 2CAN029305 Page 2 l 1 cc: Mr. James L. Milhoan ! 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- I Russellville, AR 72801 1 Mr. Roby Bevan ! NRR Project Manager, Region IV/ANO-1 l U. S. Nuclear Regulatory Commission i NRR Mail Stop 13-H-3 ! One White Flint North l 11555 Rockville Pike l Rockville, Maryland 20852 Mr. Thomas W. Alexion NRR Project Manager, Region IV/ANO-2 , U. S. Nuclear Regulatory Commission NRR Mail Stop 13-H-3 One White Flint North I 11555 Rockville Pike Rockville, Maryland 20852 , Ms. Greta Dicus ; Arkansas Department of Health ; Division of Radiation Controls , and Emergency Management : 4815 W. Markham Street Little Rock, AR 72205 5 e 4 , u
STATS OF ARKANSAS ) ,
) SS COUNTY OF POPE )
s t Affidavit I, J. W. Yelverton, being duly sworn, subscribe to and say that I am Vice President, Operations ANO for Entergy Operations, that I have full authority to execute this affidavit; that I have read the document numbered 2CAN029305 and know the contents thereof; and that to the best , of my knowledge, information and belief the statements in it are true.
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(bbO '? /4 -en fD - y/J.W/Yelverton I SUBSCRIBED AND SWORN TO before me, a Notary Public in and for the ! County and State above named, this S Y u day of Ixitum- , 0 ' 199k.Y T] W.t><- Cu_< w (/ Notary Public j Hy Commission Expires: !
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a _ I i' M. JANE DAVDSON notorr Nbk: . POPE COUtM. 4AWANSAS a 2ac2 p Ec, ; u_ 1
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ATTACHMENT j PROPOSED TECHNICAL SPECIFICATION .; AND ., l RESPECTIVE SAFETY ANALYSES j IN THE MATTER OF AMENDING , f LICENSE NO. NPF-6 a ENTERGY OPERATIONS, INC. <! i ARKANSAS NUCLEAR ONE, UNIT TWO l l DOCKET NO. 50-368 : i i i i I
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Pronosed Chnnee This proposed change revises ANO-2 TS Figure 3.6-1 containment internal pressure lower limit from 12.8 to 13.2 psia. Backcround Over the past 10 cycles, changes have been made in the AND-2 fuel design and core physics parameters which have affected the Large Break Loss of Coolant . Accident (LBLOCA) analysis. These changes, in addition to any identified input parameter discrepancies have been evaluated case by case. To address each , issue, a conservative change to the appropriate input parameters was made in-
- the affected portion of the LBLOCA analysis, which was then reevaluated to determine the effect on the results. Operating margin to the linear heat rate assumed in the LBLOCA analysis has been used to offset any negative changes (i.e. the present LBLOCA analysis is based on a peak linear heat rate of 12.1 .
kW/ft, reduced from 14.5 kW/ft assumed in the original Safety Analysis Report [ (SAR) LBLOCA analysis). The latest such changes were identified in our letter 2CAN079201, dated July 9, 1992 (Reference 1), which resulted in a reduction in the linear heat rate from 13.5 kW/ft to 12.1 kW/ft to account for changes in the cycle 10 core physics and a discrepancy identified in the allowable initial containment conditions. In an effort to consolidate all of the changes and discrepancies that have been identified over the years and restore operating margin to the linear heat rate limit, a complete LBLOCA reanalysis was performed. The current ANO-2 LBLOCA Analysis is based on CENPD-132P Supplement 2-P. As required by the Combustion Engineering LBLOCA Safety Evaluation Report (SER) (Reference 2), the reanalysis required that the ANO-2 analysis be updated to the CENPD-132 Supplement 3-P-A (Reference 3) methodology whenever a full reanalysis was necessary. During ; this effort to update the analysis and consolidate all of the changes, the input parameters were also reviewed and adjusted accordingly to account for , potential future changes (see Anticipated Plant Changes under the Discussion section). A steam generator tube plugging limit of 10 percent is one such change that has been incorporated into the new LBLOCA analysis. j Discussion ; As indicated above, the ANO-2 LBLOCA analysis has been re performed utilizing the latest approved Combustion Engineering evaluation model (Reference 3). The ! ANO-2 input parameters have therefore been updated to the new model requirements. Additionally, the inputs were reviewed to ensure the present plant design conditions were being correctly modeled and potential future plant changes were considered. All inputs and calculations were developed by ASEA ; Brown Boveri Combustion Engineering (ABB-CE) using the approved evaluation i model methodologies. The supporting calculations for the ANO-2 LBLOCA input parameters and analysis are maintained by ABB-CE in Windsor, Connecticut. The input parameter changes are summarized below in the following four categories: ;
- 1) Latest Evaluation Model Updates !
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- 2) Past Cycle Changes 1 of 9 l
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- 3) Present Plant Data !
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- 4) Anticipated Plant Changes l Latest Evaluation !!odel Updates l t
Several changes were made to the evaluation model from CENPD-132P Supplement 2-P to CENPD-132 Supplement 3-P-A which required the input parameters to be . updated. Hence, the ANO-2 input parameters were reviewed and updated to [ conform to the new model. Changes to the evaluation model which impact the ; input parameters are: a) the limiting single failure, b) analytical i nodalization modifications, and c) axial power shape sensitivity study. ! A new limiting failure of "no single failure" is referenced in CENPD-132 Supplement 3-P-A. The present limiting single failure assumed for ANO-2 is that of a Low Pressure Safety Injection (LPSI) pump failure (based on , Supplement 2-P). This new limiting single failure allows both LPSI pumps to : operate. All High Pressure Safety Injection (liPSI) and LPSI pump flow out the ' break (flow not assumed to go to the core) is modeled to reduce containment' ; backpressure per CENPD-132 Supplement 3-P-A. This additional reduction in containment backpressure has been determined to result in higher PCTs. Therefore, the limiting failure of no single failure was assumed in the new - ANO-2 LBLOCA analysis. Changes identified in CENPD-132 Supplement 3-P-A to the CEFLASli-4A computer . l code have allowed for modifications to the nodalization in the reactor vessel lower plenum region and broken pump discharge (cold) leg. These nodalization ; changes have been incorporated into the AND-2 input parameters. ! CENPD-132 Supplement 3-P-A also documented a sensitivity study on axial power ! distribution. The axial power shape assumed for ANO-2 was verified to be consistent with that of the limiting case determined by the sensitivity study. j Past Cycle Changes l All of the following changes which have occurred over the past 10 cycles (as documented in cycle-specific reload reports under the provisions of 10CFR50.59 : which are subsequently incorporated into chapter 4A of the SAR) have been ! incorporated into the new LBLOCA analysis: t
- 1) Difference in fuel pin conditions (fuel augmentation factor, gap conductance, centerline temperature, gas pressure, etc.) j
- 2) Introduction of fuel batches that have HID-1 spacer grids _j
- 3) Removal of the hot rod augmentation penalty l
- 4) Addition of debris resistant fuel batches
- 5) Increased plugging of steam generator tubes
- 6) Reduction of the linear heat rate i
- 7) Reduction in the initial containment temperature I
- 8) Reduction in the initial containment pressure 2 of 9 l i
C Present Plant Data Most ci the input parameters were not affected by the changes made in the evaluation model, past cycle changes, or anticipated changes. For these unaffected input parameters,- the original calculations were utilized. Updates were made to any input parameter for which better information was available. In particular, bounding input parameters which originally were used to model ANO-2 and the uncompleted Blue Hills plant were updated ' to reflect ANO-2 specific numbers. Anticipated Plant Changes Based on past experiences at ANO-2 and other ABB-CE plants, changes were made to input parameters to alleviate tight operating margins and to accommodate changing plant conditions. Some of these changes are reflected in Tables 1 and
- 2. Other input parameter changes to allow for 10 percent steam generator tube plugging, maximum Refueling Water Tank (RWT) temperature of 120 'F, and minimum HPSI and LPSI flow of 678 gpm and 3222 gpm per pump, respectively were also incorporated.
Tables 1 and 2 compare the relevant input. changes made to the general system design and containment model. These tables of information are similar to those given in the SAR. Input parameters for the containment heat sinir data used in the new analysis are given in Table 6.2-35 of Attachment 1 (previously SAR Table 6.3-10). These heat sink parameters are the same as those used in the original LBLOCA analysis except for small round-off differences. However, errors have been identified in the Safety Analysis Report (SAR) Table 6.3-10 with regards to the paint thickness for heat sink 7 (0.0037 ft versus 0.0004 ft), concrete thickness for heat sink 9 (1.8219 ft versus 2.70 ft), and the surface area for heat sink 9 (118,000 ft versus 68,000 ft*). These new values are consistent with the original LBLOCA analyses and constitute corrections to the SAR table only. The only input parameter change which is considered more restrictive than the present allowable Technical Specification limits is that which limits the initial containment pressure. The ANO-2 LBLOCA analysis assumes initial containment conditions which result in the lowest peak building pressure following a LOCA. Per 10CFRSO Appendix K, the conservative analysis assumption is to minimize containment pressure. Lower PCTs are expected as a result of an increase in the initial containment pressure. Using an initial containment pressure lower limit of 13.2 psia rather than 12.8 psia in the LBLOCA anelysis, necessitates a change to present Technical Specifications (Figure 3.6-1) to ensure a conservative constraint. Other Technical Specification input parameters which are reflected in the LBLOCA reanalysis' use the Technical Specification limit or a value which is more conservative. 3 of 9
i Censervative input parameters, with respect to the Technical Specification , limits, were used when modeling such parameters as the HPSI and LPSI flow, and > Safety Injection Tank (SIT) pressures and inventory. Future Technical . Specification changes may be requested based on these conservative parameters in conjunction with ongoing efforts to update the small break LOCA evaluation. i The emergency core cooling system (ECCS) performance and minimum containment I pressure analyses are in section 6.3.3.2 of the ANO-2 SAR. The revision to this section and the addition of section 6.2.1.6 as a result of the new - analysis is given in Attachment 1 (note the references are numbered sequentially for Attachment I and have not been assigned a SAR reference number). A comparison of the SAR input parameters to the new analysis is given in Tables 1 and 2 and a comparison of the results in Table 3. The SAR analysis indicated the limiting break as a 1.0 Double Ended Guillotine ! break in the Pump Discharge (DEG/PD) with a PCT of 2078 F. For Cycle 10, this l limiting SAR break size was evaluated and resulted in a PCT of 2086'F (Reference 1). A new break size of 0.6 DEG/PD has been determined as the limiting break utilizing the latest approved evaluation model with the updated i ANO-2 input parameters. A PCT of 2142 F is predicted for the new limiting break, which is below the 2200'F limit defined in 10CFR50.46. The maximum clad oxidation was calculated as 8.9 percent and the maximum core wide oxidation is , less than 0.843 percent which are also within the allowed limits of 17 percent and 1 percent respectively. The latest approved ABB-CE evaluation model does i not utilize the new best-estimate uncertainty analysis allowed by 10CFR50.46, but rather conforms to Appendix K requirements, and therefore is considered to be conservative. , I As noted above, the new ANO-2 LBLOCA analysis assumes an initial containment pressure of 13.2 psia, which is more restrictive than the present Technical Specification limit of 12.8 psia. Therefore, ANO-2 Technical Specification Figure 3.6.1 is being revised to reflect a more restrictive minimum pressure i limit of 13.2 psia. This will ensure the input parameters for the new ANO-2 l LBLOCA analysis are conservative with respect to the Technical Specification limits. 4 Determination of No Sienificant Hazards Considerations
- l An evaluation of the proposed Technical Specification changes has been l performed in accordance with 10CFR50.91(a)(1) regarding no significant hazards ,
consideration using the standards in 10CFR50.92(c). A discussion of those standards as they relate to this amendment request follows: l Criterion 1 - Does Not Involve A Significant Increase in the Probability or Consequences of An Accident Previously Evaluated. Containment internal pressure is not an event initiator of any accident analyzed in the ANO-2 Safety Analysis Report (SAR) and does not affect the i L probability of occurrence of any event previously analyzed. Therefore, this change does not increase the probability of any accident previously evaluated. . 4 of 9 ; l
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i Increasing the initial contalument pressure from 12.8 psia to 13.2 psia is in j the conservative direction and will not result in an increase in' the : consequences of the LBLOCA analysis. This change is requested based on a- j LBLOCA analysis that has included cumulative cycle fuel design and core physics ! changes, anticipated plant changes (10% tube plugging), and utilization of the ! latest approved evaluation model. The sum of these changes have resulted in an ! increase in the LBLOCA PCT. A new PCT of 2142 F has been calculated, which remains bounded by the 2200 F limit as defined by 10CFR50.46. Due to dose i calculations for the LBLOCA being totally independent from the ECCS analysis - (based on Technical Information Document 14844), the increase in PCT does not i affect the dose calculations. Therefore, this change does not constitute a l significant increase in the consequences of an accident previously evaluated. [ i Criterion 2 - Does Not Create the Possibility of a New or Different Kind of ; Accident from any Previously Evaluated. The proposed change does riot involve any design changes, or plant i The new lower limit for containment pressure represents more j modifications. restrictive limitations than that imposed by the present Technical ! Specifications and constitutes a conservative change in plant operation. l Therefore, this change does not create the possibility of a new or different kind of accident from any previously evaluated. 1 The new LBLOCA analysis performed and referenced in this submittal will not i modify the plant. The analysis was performed using the latest ABB-CE approved ! evaluation model and conservative input parameters to bound the ANO-2 design. j Use of the new ANO-2 LBLOCA input parameters and evaluation model does not ; create the possibility of a new or different kind of accident from any { previously evaluated. l l Criterion 3 - Does Not Involve a Significant Reduction in a Margin of Safety. ; t - The Region of Acceptable Operation of ANO-2 TS Figure 3.6-1 has been evaluated ! and shown to result in peak containment pressures within the design pressure as j was the case with the original analyses. As indicated above, the LBLOCA l < analysis is not negatively impacted by this change, but due to the combined [ evaluation with other conservative input parameter changes, a higher PCT is ! calculated. ! The new LBLOCA analysis performed for ANO-2 was done with an approved ; evaluation model that complies with the requirements of Appendix K, and has ; resulted in a higher PCT (2142 "F versus 2086 F for cycle 10) and greater core j . wide clad oxidation (0.843 % versus 0.617%). These results are attributed to j the input parameter changes. Although the PCT and core wide clad oxidation has- , increased, the results still are in compliance with the acceptance criteria set ; forth in 10CFR50.46 which establish ifmits and required design margins, and j therefore, does not involve a significant reduction in a margin of safety. Therefore, based on the reasoning presented above and the previous discussion of the amendment request, Entergy Operations has determined that the requested l change does not involve a significant hazards consideration. I 4 l J 5 of 9 i
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l Table 1 -l General System Parameters I Quantity SAR Value New Value l Reactor Power Level (MWt) 2882 2900 i i Peak Linear Heat Rate (kW/ft) 14.5* 13.5 ;
'I Gap Conductance at Peak Linear Heat Rate 1633* 1572 i 2
(BTU /br-ft _p) ; Fuel Centerline Temperature at Peak L Linear Heat Rate ( F) 3478* 3359 l Fuel Average Temperature at Peak Linear Heat Rate ( F) 2192* 2129 Hot Rod Gas Pressure (psia) 1206* 1114 j Moderator Temperature Coefficient at Initial Density (Ak/k/*F) +0.5 x 10-' +0.5 x 13 ' ! Total System Flow Rate (1bs/hr) 120.4 x 10' 119.9 x 10' Core Flow Rate (1bs/hr) 116.2 x 10' 115.7 x 10' Initial System Pressure (psia) 2250 .2250 Core Inlet Temperature ('F) 557.5 556.7 'j Core Outlet Temperature ('F) 616.8 616.8 Safety Injection Tank Pressure (psia) 615 550 Safety Injection Tank Gas / Water Volume 470/1380 500/1350 (ft')
- Cycle specific analyses input assumptions, such as that performed for Cycle 10, are not reflected in the SAR table. i t
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'l Table 2 Containment Physical Parameters ;
SAR Value- New Value j Net Free Volume-(ft') 1.82 x 10' 1.82 x 10' { l Containment Initial Conditions Humidity (%) 100 .100 j i Containment Temperature (*F) 90* 60 Initial Pressure (psia) 14.7* 13.2 Initial Time for: i Spray Flow (seconds) 20.0 20.0 b 4 Fans (seconds) 9.0 0 Containment Spray Water: 3 Temperature ( F) 40 40 i
- Total Flow Rate, Both Pumps (gpm) 4800 4800 !
t Individual Fan Cooling Capacity 28,663 28,663 , at 300'F (Btu /sec)
- Cycle specific analyses input assumptions, such as that performed ,
for Cycle 10, are not reflected in the SAR table. l
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f Table 3 Peak Clad Temperatures and Oxidation Percentages For the Break Spectrum SAR Results Peak Clad Clad Oxidation (%) Break Terperature ('F1 Local Core-Wide-1.0 DES /PD 2066 11.33 <0.580 0.8 DES /PD 2066 11.33 <0.602 0.6 DES /PD 2062 11.13 <0.578 0.5 ft* S/Pn 1978 9.37 <0.444 1.0 DEG/PD 2078 11.82 <0.617 0.8 DEG/PD 2070 11.48 <0.610 0.6 DEG/PD 2055 10.83 <0.534 New Analysis Peak Clad Clad Oxidation (%) Break Temperature (*F) Local Core-Wide 1.0 DES /PD 2129 8.58 <0.672 0.8 DES /PD 2129 8.58 <0.684
'l 0.6 DES /PD 2122 8.43 <0.697-1.0 DEG/PD 2132 8.64 <0.714 0.8 DEG/PD 2135 8.72 <0.756 0.6 DEG/PD 2142 8.90 <0.843 0.4 DEG/PD 2112 8.21 <0.705 DES /PD - Double Ended Slot in Pump Discharge S/PD - Slot in Pump Discharge DEG/PD - Double Ended Guillotine Pump Discharge
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.i References t
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- 1) .ANO Letter 2CAN079201, " Proposed ANO-2 Technical Specifications to Revise -l Containment Parameter Limits and Reduce Peak Linear flest Rate Limit", l
- ' July 9, 1992.
- 2) NRC Letter Dennis M. Crutchfield (NRC) to A. E. Scherer (CE), " Safety 'f Evaluation of Combustion Engineering ECCS Large Break Evaluation Model i and Acceptance for Referencing of Related Licensing Topical Reports", ,
July 31. 1986. -l 1
- 3) CENPD-132P, " Calculative Methods for the C-E Large Break LOCA Evaluation l Model", August 1974. !
I CENPD-132P, Supplement 1, " Calculational Methods for the C-E Large Break j LOCA Evaluation Model", February 1975. j l CENPD-132P, Supplement 2-P, " Calculational Methods for the C-E Large i Break LOCA Evaluation Model", June 1975. ! l CENPD-132, Supplement 3-P-A, " Calculative Methods for the C-E Large { Break LOCA Evaluation Model for the Analysis of C-E and W Designed ! NSSS", June 1985. i
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