ML20205L234

SFP Criticality Analysis

ML20205L234
Person / Time
Site:	McGuire, Mcguire
Issue date:	04/05/1999
From:	DUKE POWER CO.
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ML20205L214	List: ML20205L209 ML20205L225 ML20205L234 ML20205L243 ML20205L253
References
NUDOCS 9904140194
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{{#Wiki_filter:ATTACHMENT 6 MCGUIRE SPENT FUEL POOL CRITICALITY ANALYSIS i i ~ 9904140194 990405 PDR ADOCK 05000369.- P PDR. Page 1 of 41 MCGUIRE SPENT FUEL POOL CRITICALITY ANALYSIS Table of Contents Section Page

1.0 INTRODUCTION

2 1.1 Spent Fuel Pool Storage Rack Design 3 1.2 New Fuel Storage Vault Design 4 2.O COMPUTER CODES AND METHODOLOGY 5 3.0 CRITICALITY ANALYSIS 7 3.1 No Boron 95/95 k 8 err 3.1.1 No Boron 95/95 k - Burnup Credit 10 ert 3.1.2 No Boron 95/95 k,gg - IFBA Credit 12 3.2 Boron Credit 95/95 k 13 org 3.3 New Fuel Storage Vault Analysis 16 4.0 ACCIDENT CONDITIONS 18 5.0 BORON CREDIT

SUMMARY

20 6.0 REGION INTERFACE RESTRICTIONS 21 7.0

SUMMARY

OF RESULTS 22

8.0 REFERENCES

23 i l {-

J Page 2 of 41

1.0 INTRODUCTION

This attachment describes the criticality analysis of the McGuire Nuclear Station spent fuel storage racks. This analysis takes credit for soluble boron in the spent fuel pool water as allowed in. Reference 8.1 of this attachment. It should be noted that the Westinghouse methodology in Reference 8.1 was used as the basis for the methodology used in this analysis. However, since this analysis was performed by Duke

Energy, some minor differences in the application of the methodology exist.

For example, this analysis used a different set of computer codes to perform the calculations (as described in Section 2.0) instead of those described in Reference 8.1. So, while the process and criteria defined in the " Westinghouse Spent Fuel - Rack Criticality Analysis Methodology" were followed, the methodology used for this submittal, which is based on the Westinghouse methodology, is described in this attachment. The storage rack design for the McGuire spent fuel pools is a two i region'- design. Each region utilizes the poison material Boraflex. .Due to the degradation of the.Boraflex poison material and the need to establish acceptable spent fuel storage limits, each region has been divided-into. two sub-regions; with and without credit for Boraflex. For the regions taking credit for p l Boraflex, a minimum amount of Boraflex was assumed that is less than the original design - minimum Bo areal density. The sub-i regions are defined as follows: Region lA takes credit for 25% of the original Boraflex material Region 1B no credit for Boraflex Region 2A takes credit for 50% of the original Boraflex material

• Region 2B no credit for Boraflex Within each sub-region, the criticality analysis takes credit for burnup and storage configuration restrictions to achieve l

acceptable spent fuel storage limits. Two storage configurations are. defined' for each of the four regions: Unrestricted and l Restricted storage. A third loading

pattern, Checkerboard storage, was defined for Regions 1B, 2A and 2B.

Unrestricted storage allows storage in all cells without restriction on the storage' configuration ~. Restricted storage allows storage of higher reactivity fuel when restricted to a certain storage configuration with lower reactivity fuel. Checkerboard storage allows storage of the highest reactivity fuel in each region when checkerboarded with empty storage cells. I l l I e Page 3 of 41 In addition, credit is also taken for Integrated Fuel Burnable Absorbers (IFBAs). IFBA credit is only taken for Region lA since this is the ' region ' where the new fuel will be stored prior to refueling the reactor. The main design criteria for the McGuire spent fuel storage rack criticality analysis is that kerc < l.0 with no boron (including I tolerances and uncertainties) and keer < 0.95 with credit for soluble boron. The soluble boron credit required for the storage i configurations in all regions is 440 ppm for normal conditions and 1170 ppm for accident conditions. 1.1 Spent Fuel Storage-Rack Design McGuire has two independent identical spent fuel pools for Units 1 and 2. The spent fuel storage rack in each pool consists of a two-region design. The Region 1 area of the spent fuel pools is designed and generally reserved for temporary storage of new or partially irradiated fuel'which would not qualify for storage in the Region 2 area. The storage cell configuration in this region represents a less reactive array than that of Region 2. The stainless steel cells are spaced at 10.4 inches and were constructed with a 2 minimum 0.02 gm/cm loading of Bo neutron absorbing material i attached to the exterior cell wall wrapper plate. Region 1 has a i capacity which is just sufficient to accommodate both a complete off. load of the reactor core and storage of a reload fuel batch. With the larger fuel batch sizes to accommodate McGuire's 18-month cycle lengths, there are very few unused cells in Region 1 during an outage. The basic spent fuel storage pool rack arrangement for units 1 and 2 is shown in Figure 1. The Region 1 area of the pool is highlighted and a schematic of the Region 1 cell configuration is also provided. The Region 2 area of the spent fuel pools is designed and generally used for normal, long term storage of permanently discharged fuel that has achieved qualifying burnup levels. The storage cell configuration in this region represents a more reactive array than that of Region 1. The stainless steel cells are assembled in a checkerboard pattern, producing a honeycomb structure of " cell" and "non-cell" locations. This configuration has a much tighter center-to-center pitch of 9.125 inches. These cells.also utilize a neutron absorbing material with a slightly 2 lower minimum B o areal density (0.006 gm/cm ) than that used in i Region 1. This region has a nominal capacity.of 1177 locations.

\\ Page 4 of 41 I l The basic spent fuel storage pool rack arrangement for units 1 and 2 is shown again in Figure 2 with the Region 2 area of the l pool. highlighted and a schematic of the Region 2 cell configuration provided. 1.2 New Fuel Storage Vault Design The new fuel storage vaults which are used for temporary dry storage of unirradiated reload fuel are built on 21 inch centers and are currently licensed for maximum nominal fuel enrichments of 4.75 %U-235. To accommodate a new Westinghouse Performance Plus fuel design, previously approved analytical methods were used to demonstrate that this new fuel containing up to 4.75 %U-235 can be safely stored in these fuel racks. No other restrictions beyond this enrichment limit are applicable to storage in the new fuel vaults. Discussion of the methods used to justify this increased limit can be found in bection 3.3. No technical specification changes are applicable to the new fuel storage vaults. l l I L

y Page 5 of 41 t ' 2. 0.. COMPUTER CODES AND METHODOLOGY The methodology emp1gred in this analysis is based on the " Westinghouse Spent Fuel Rack Criticality Analysis Methodology" i. (Reference'8.1). While, the process and criteria defined in the l Westinghouse methodology were followed, the methodology used for this. submittal, which is based on the Westinghouse methodology, is described in this attachment. The methodology employed in this analysis uses botl the CASMO-3/ TABLES-3/ SIMULATE-3 and SCALE system of codes for <riticality analysis.. CASMO-3/ TABLES-3/ SIMULATE-3 is used primarily and SCALE with KENO-Va is used for limited applications. The burnup credit approach to fuel rack criticality analysis-requires calculation and comparison of reactivity values over a range of burnup and initial enrichment conditions. In order to l accurately model characteristics of irradiated fuel which impact reactivity, a criticality analysis method capable of evaluating arrays of these irradiated assemblies is needed. In this license submittal, the advanced nodal methodology combining CASMO-l 3/ TABLES-3/ SIMULATE-3 is used for this purpose. CASMO-3 is an integral transport theory code, SIMULATE-3 is a nodal diffusion theory code, and TABLES-3 is a linking code which reformats CASMO-3 data for.use in SIMULATE-3. This methodology permits direct coupling of incore depletion calculations and resulting fuel isotopics with out-of-core' storage array criticality analyses. The CASMO-3/ TABLES-3/ SIMULATE-3 methodology has been previously approved for use in criticality analysis of the McGuire spent fuel storage racks (Reference 8.2). 1 The. CASMO-3/ TABLES-3/ SIMULATE-3 methodology is validated by comparison to measured results of fuel storage critical l experiments. The criticality experiments used to benchmark the methodology were the Babcock and Wilcox close proximity storage critical experiments performed at the CX-10 facility (Reference 8.3). The B&W critical experiments.used are specifically designed for benchmarking reactivity calculation techniques. The criticality experiments examined have similar nuclear characteristics to spent fuel storage and are applicable to conditions encountered during the handling of LWR fuel outside reactors. l The results of the CASMO-3/ TABLES-3/ SIMULATE-3 benchmark l calculations are shown in Table 1. There are no significant I trer.ds in the results with respect to moderator soluble boron concentration, array spacing, or boron level in the isolation sheets. l u Page 6 of 41 The SCALE system of computer codes was used to model the Checkerboard storage configurations, new fuel storage vault and various biases and uncertainties related to the Boraflex material (self shielding, shrinkage and gaps). This methodology utilizes three dimensional Monte Carlo theory. Specifically, this analysis method used the CSAS25 sequence contained in Criticality Analysis Sequence No. 4 (CSAS4). CSAS4 is a control module contained in the SCALE-4.2 system of codes. The CSAS25 sequence utilizes two cross section processing codes (NITAWL and BONAMI) and a 3-D Monte Carlo code (KENO-Va) for calculating the effective multiplication factor for the system. The 27 Group NDF4 cross section library was used exclusively for this analysis. The KENO-Va methodology is also benchmarked to measured results of fuel storage critical experiments. The criticality experiments used to benchmark the KENO-Va methodology were from the PNL reports PNL-3314 (Reference 8.4), PNL-2438 (Reference 8.5) and PNL-6205 (Reference 8.6). The criticality experiments examined have similar nuclear characteristics to spent fuel storage and are applicable to conditions encountered during the handling of LWR fuel outside reactors. The results of the KENO-Va benchmark calculations are shown in Table 2. There are no significant trends in the results with respect to fuel pin spacing, array spacing, poison loading and material or fuel enrichment. For additional verification that the models used in the McGuire criticality analysis are accurate, calculated kergs from CASMO-3, SIMULATE-3 and KENO-Va are compared in Table 3. The results listed in Table 3 show very good agreement between the transport theory, diffusion theory and Monte Carlo codes, with CASMO-3 and SIMULATE-3 being slightly conservative compared to KENO-Va. L. Page 7 of 41 3O CRITICALITY AFALYSIS This section d.tscribes the criticality analysis performed to determine the spent ' fuel storage limits for the McGuire spent fuel storage racks. 1 The following assumptions are used in the spent fuel pool { criticality analysis. j 1.All fuel designs used, or planned for use, at McGuire were analyzed. This included Westinghouse Standard (STD), Optimized (OFA) and Performance Plus (PF+) and Framatome Mark BW (MkBW) fuel designs. All fuel designs are analyzed for all cases and only the most reactive fuel design is used to set the storage requirements.

2. All conditions are modeled at both 68 and 150 F.

Only the most reactive temperature is used to set the storage requirements. l

3. All calculation s are 2-D; i.e. no axial effects are modeled.

4. No xenon conditions are assumed in the storage racks.

5.No credit is taken.for the spacer grid material.

6. McGuire Region lA contains 25% of its original thickness and areal' density.

7 McGuire Region 1B contains no Boraflex.

8. McGuire Region 2A Boraflex contains 50% _of its original thickness and areal density.

9. McGuire Region 2B contains no Boraflex.

10.The Boraflex panels are reduced in the width direction to account for 0.25 inches assumed shru.kage. 11.The Boraflex panels are reduced in the axial direction to account for measured shrinkage. l 12.No reactivity penalty is included for gaps in the Boraflex panals (see Section 3.1). 13.The nominal coating on IFBA rods is assumed to be 1.0X which is the minimum standard loading of f ered by the vendor. The IFBA coating is reduced to'75% of this value to account for 1 the IFBA coating not being applied for the full length of the fuel rod. l p, F

Page 8 of 41 l 3.1-No Boron 95/95 kore This section describes the methodology used to determine the limits for the k.cz calculation with no boron including all biases and uncertainties (95/95 kore). The 95/95 kort must be less than 1.0 with no boron. The calculation of the 95/95 kort must consider various biases and i uncertainties related to the materials and construction of the racks. _Specifically, the biases and uncertainties accounted for in the McGuire spent fuel pool criticality analysis are the bias and uncertainty associated with the benchmarking of the methodology, biases and uncertainties associated with the affect t of Boraflex shrinkage, a bias to account for the underprediction of reactivity due to self shielding and the uncertainty due to mechanical tolerances from the manufacturing process. The mechanical tolerance uncertainty is comprised of the following components: cell ID, CTC spacing, cell thickness, Boraflex width, plenum thickness, enrichment, fuel pellet dish volume, fuel pellet theoretical density, fuel pellet OD, clad OD and assembly position within the storage cell. For the no boron 95/95 keer, these biases and uncertainties are generated at no boron conditions. Additional uncertainties related to burned fuel are discussed with the burnup credit methodology. Table 4 lists the biases and uncertainties for each region. l The uncertainties associated with the affect of Boraflex shrinkage include the following. A reactivity bias is included I to account for an assumed 0.25 inches of shrinkage in the width of the Boraflex panels. A reactivity uncertainty is included to account for the 95/95 worst case shrinkage in the axial direction ( (end pullback of the top and bottom). No reactivity penalty is I included.to account for gaps in the middle of the Boraflex panels.

However, an analysis was performed to determine the maximum gap size before an increase in reactivity occurs.

This i-analysis. looked at a gap in one out of four panels, two out of four and four out of four panels. The results of this analysis, and the interpretation of recent measured data indicate that no reactivity penalty is necessary to account for gaps in the Boraflex panels. A no boron 95/95 maximum design kort is defined to.be 1.0 less the combination of all the biases and uncertainties. For the final kort to remain less than 1.0, the calculated keer must remain less than the no boron maximum design kort. Since the combined biases and1 uncertainties are dependent on the fuel storage rack, four no boron 95/95-maximum design korts are defined, one for each region of'the pool. These maximum design korrs are listed in Table 4.

Page 9 of 41 To determine the maximum enrichment for Unrestricted storage, CASMO-3 is use.d to iterate on enrichment until the calculated kere from CASMO-3 meets the no boron 95/95 maximum design kort. Since CASMO-3 is a lattice code, itc calculations are for single assemblies in an infinite array, which is representative of the Unrestricted 100% storage option. The results of the fresh fuel limits for Unrestricted storage are summarized in Table 6. Assemblies which de not qualify for unrestricted storage must be stored in a rentricted storage configuration. Two restricted storage configurations are employed; Restricted storage with low reactivity ' filler' assemblies in a specified storage pattern and Checkerboard storage with empty cells in a specified storage pattern. For Rest ricted storage to be effective, the storage requirements must be carefully selected to optimize the use of the spent fuel storage cells for the current and expected inventory of fuel for each region. For this reason, a different Restricted storage pattern is defined for each region of the McGuire spent fuel pools. For Region lA, a 3 out of 4 storage prttern is defined which allows assemblies not qualified for Unrestricted storage to be stored in 3 out of every 4 locations with the 4 bei@ a th qualified low reactivity ' filler' assembly. This storage pattern is shown in Figure 3. For Regions 1B and 2A, two different checkerboard storage patterns are defined which allow assemblies not qualified for Unrestricted storage to be stored in 2 out of every 4 locations with the other 2 being qualified lcw reactivity ' filler' assemblies. This storage pattern is shown in Figure 4. For Region 2B, a 1 out of 4 storage pattern is defined which allows assemblies not qualified for Unrestricted storage to be stored in 1 out of every 4 locations with the other 3 being qualified low reactivity ' filler' assemblies. This storage pattern is shown in Figure 5. By storing the more reactive assemblies not qualified for Unrestricted storage with less reactive fuel, the tierall reactivity of the array is able to stay beneath the no boron 95/95 maximum design ke r r. The Unrestricted and Restricted storage patterns for each region will allow optimum usage of all the storage cells in the McGuire racks for a wide range of fuel assemblies. Prior to performing any reactivity calculations, the requirements of either the filler or restricted assemblies must be selected. In this analysis, the requirements for the restricted assemblies were selected first and the filler requirements were then calculated for the restricted assembly requirements chosen. The fresh fuel limits defined for Restricted storage are summarized in Table 6. Page 10 of 41 The maximum enrichment for the Filler fuel in the Restricted storage configurations is calculated using SIMULATE-3. To model the Restricted storage patterns, the model must have the ability to analyze different assemblies in the same problem. This required the nodal code. SIMULATE-3 was executed to calculate kort of the Restricted storage array containing dissimilar fuel. The maximum enrichment for the filler fuel is determined by iterating on enrichment until the calculated kcc from SIMULATE-3 meets the no boron 95/95 maximum design kerr. The results of the fresh fuel limits for Filler fuel in the Restricted storage configuration are summarized in Table 6. Assemblies which do not qualify for Unrestricted or Restricted storagt must be stored in a checkerboard storage pattern with empty storage locations. Checkerboard storage will allow storage of all fuel in each region. The goal of Checkerboard storage is to be able to store the most reactive fuel assembly in each region. This is accomplished by storing the most reactive assembly with empty storage locations i to keep the overall reactivity of the array beneath the required reactivity limit. To determine the storage pattern for Checkerboard storage, the calculated kore is raried by varying the number of empty cells until the calculated kert is less than or equal to the maximum design kere. The calculated kores are taken from KENO-Va. A different Checkerboard storage pattern is defined for each region of the McGuire spent fuel pools. Since restricted storage for Region lA includes fuel up to the maximum allowed enrichment, Checkerboard storage is not necessary for this region. The Checkerboard storage patterns are shown in Figures 6 and 7. While it is intended to use the Unrestricted and Restricted storage patterns for optimum usage of all the storage cells, Checkerboard storage allows storage of the most reactive fuel in all regions if it becomes necessary. 3.1.1 No Boron 95/95 kere -Burnup Credit In order to store fuel with enrichments higher than the maximum enrichment limits for fresh fuel, the concept of reactivity equivalencing is employed. Reactivity equivalencing determines I an equivalent reactivity by introducing a reactivity effect that l was not previously considered. In this

case, the negative l

reactivity from fuel burnup is used to offset the positive reactivity from higher enrichments until the reactivity is equivalent to that of the fresh fuel maximum enrichment case (i e. the no boron 95/95 maximum design k.gg). I Page 11 of 41 To use burnup

credit, additional uncertainties related to 1

I depleted - fuel must also be accounted for. The only burnup related uncertainty included in the no boron 95/95 maximum design f k calculation is the reactivity increase associated with the eer removal of Burnable Poison assemblies (BP-pull). All other burnup-related uncertainties, namely the uncertainty on the I l calculated reactivity versus burnup and the uncertainty on the measured burnup, will be accounted for with boron credit as discussed in Section 3.2.. ] I A bias is applied in the burnup credit calculations to account for a reactivity increase due to the. shadowing effect of a BP. For burnup credit calculations, the standard criticality assumption was made that no removable poisons are in the l assembly. However, an assembly which has a BP removed after its first cycle of operation is more reactive than an assembly that never contained a BP. A BP-pull bias is applied to account for this affect. A study of a database of BP-pull data for McGuire l determined a maximum BP-pull reactivity increase of 0.01 Dk at 14 GWD/MTU. The bias is assumed to be linear from 0 GWD/MTU to the maximum bias at 14 - GWD/MTU and is constant beyond 14 GWD/MTU. This is conservative because the reactivity of the BP-pulled assembly tends to approach the reactivity of the never BP'd assembly by EOL. For burnup credit calculations, the bias only needs to be applied for assemblies with burnup.

Hence, for l

Unrestricted storage burnup credit calculations, CASMO-3 is used and hence, the entire bias is applied, since every assembly has burnup For the SIMULATE-3 model used for the Restricted storage calcuations, only the Filler fuel has burnup. The Restricted fuel is modeled as fresh fuel with the maximum enrichments from Table 6. Therefore, an appropriate ratio of the BP-pull bias is applied for the Restricted storage array since only part of the l arr i has burnup. l l Sunanarizing, the BP-pull bias for each region is as follows, i i 0.01x BU i Unrestricted Storage All Regions BP-pull bias = l 14 0.0025 x BU Restricted Storage Region lA BP-pull bias = 14 0.005 x BU Restricted Storage Region 1B BP-pull bias = 14 0.005 x BU Restricted Storage Region 2A BP-pull bias = i 14 0.0075 x BU Restricted Storage Region 2B BP-pull bias = 14 I

F Page 12 of 41 Where: BU = Assembly burnup in GWD/MTU up to a maximum of 14 l To model fuel burnup, CASMO-3 was used to deplete the fuel under l hot full power reactor conditions. CASMO-3 restarts were then performed to model the depleted assemblies in the storage racks. This ensures the reactivity of the depleted assembly is l explicitly determined in the storage rack conditions. CASMO-3 restarts are performed at 5 GWD/MTU intervals from 0 to 60 GWD/MTU and at 0.5 w/o enrichment intervals from 2.0 to 4.5 w/o and the maximum 'nrichment of 4.75 w/o. A TABLES-3 library was also created from the CASMO-3 storage rack restart data to allow modeling the burned fuel in SIMULATE-3. The burnup credit calculations are performed similar to the calculations that determined the maximum fresh fuel enrichments except that instead of varying the enrichment, the burnup is varied. As with the maximum fresh fuel enrichment calculations, for Unrestricted storage, the calculated keres come from CASMO-3, specifically, the storage rack restart cases with burned fuel. For Restricted storage, the calculated keres come from SIMULATE-3. The calculated kerrs are used to determine minimum burnup limits for each enrichmt.at to ensure that the 95/95 storage rack keer is 1.0. The burnup limit is the burnup where the calculated kar equals the no boron maximum design keer from Table 4 minus tr a appropriate BP-pull bias discussed above. The minimum burnup requirements for each enrichment are determined by linearly interpolating between the calculated burnups. This linear interpolation assumes that the calculat ed kere vs. burnup curve is linear. This is a very good assumption over small ranges of burnup. The minimum burnup requirements for each enrichment are then plotted versus burnup and enrichment to yield a storage curve. A separate storage curve is generated for each type of storage and each region. A fuel assembly qualifies for storage if its burnup and enrichment fall above the storage curve. The resu its of the burnup credit calculations are summarized in Tables 7 through 9. The s t.orage curves are shown in Figures 8 and 9. 3.1.2 No Boron 95/95 keer -IFBA Credit This section describes the methodology for reactivity l equivalencing taking credit for integrated fuel burnable absorber l (IFBA) rods. IFBA rods are fuel rods with a thin layer of ZrB2 l sprayed on the fuel pellet. This coating provides a reactivity holddown at beginning of cycle. For the criticality analysis,

l Page 13 of 41 this coating provides an integral poison in the fuel that may be taken credit for in the analysis. Credit for normal burnable poison rods is not allowed since these poison components can be removed from the fuel assembly. In order to store fresh fuel more efficiently, the concept of reactivity equivalencing is employed. Reretivity equivalencing determines an equivalent reactivity by introducing a reactivity -effect that was not previously considered. In this case, IFBA rods are introduced into the calculation and the enrichment is varied until the calculated keer is equivalent to that of the fresh fuel maximum enrichment case (i.e. the no boron 95/95 maximum design keer). Credit for IFBA is only utilized in Region lA, where the fresh fuel is to be stored. The reactivity of Regions 1B, 2A and 2B are such that there is no real benefit for IFBA credit since these regions will not typically store fresh fuel. The use of IFBA credit for fresh fuel in Region lA will permit most of the fresh fuel to be stored within the limited number of locations available in this region. The calculated keers come from the infinite lattice code CASMO-3. The calculated k. css are used to determine maximum enrichment for each discrete number of IFBA rods to ensure that the 95/95 storage rack keer is < l.0. The maximum enrichment requirements for each number of IFBA rods are determined by iterating on enrichment until the calculated keer is less than the no boron 95/95 maximum design kort. The maximum enrichment requirements for each number of IFBA rods are then plotted versus enrichment and number of IFBA rods to yield an Unrestricted storage curve. A fuel assembly qualifies for Unrestricted storage if its enrichment and number of IFBA rods fall above the Unrestricted storage curve. Assemblies which fall below the Unrestricted storage curve must be stored in a Restricted loading pattern. The results of the IFBA credit calculations are summarized in Table 10. 3.2 Boron Credit 95/95 kerr This section describes the methodology used to determine the amount of soluble boron required to maintain the 95/95 keer < l 0.95. The soluble boron required consists of two components; the boron required to reduce the no boron 95/95 kert from 1.0 to 0.95 and the boron required to account for uncertainties in the reactivity equivalencing methods. The sum of these two Page 14 of 41 components of required boron represent the amount of soluble boron credit needed. This required boron concentration must be less than the amount of boron available for normal conditions. The amount of boron available for normal conditions is determined from an appropriate boron dilution analysis. Additional boron requirements are needed to compensate for reactivity increases as a result of postulated accidents. These are discussed in the Section 4. Just as with the no boron 95/95 keer calculation, the calculation of the soluble boron credit 95/95 kort must consider various biases and uncertainties related to the materials and construction of the racks. The same biases and uncertainties for the no boron 95 percent probability at a 95 percent confidence level kerr are determined for the soluble boron credit 95/95 koge calculation. The only difference in the calculation of the uncertainties is that the calculations are now performed with the boron concentration required to maintain kort less than 0.95. Only the mechanical tolerance uncertainty was explicitly calculated with boron. Given the extremely small enange in the uncertainty between no boron and boron conditions, and the significant amount of margin available in the amount of boron available, the Boraflex related uncerta:.nties were not recalculated at boron conditions. Table 5 lists the boron credit biases and uncertainties for each region. The soluble boron credit 95/95 maximum design kort is then 0.95 less these biases and uncertainties. For the final keer to remain less than 0.95, the calculated kere must remain less than. the boron credit maximum design kort. Since the combined biases and uncertainties are dependent on the fuel storage rack, four boron 1 credit 95/95 maximum design korgs are defined, one for each region of the pool. These maximum design korts are listed in Table 5. To determine the boron concentration required for korr 5 0.95, SIMULATE-3 is used to iterate on the boron concentration using the appropriate fresh fuel enrichment for each region until the calculated keer from SIMULATE-3 is less than the soluble boron credit-95/95 maximum design korr. Two sets of cases are run for each region for Unrestricted and Restricted storage. The appropriate fresh fuel enrichments for each case are the maximum fresh fuel enrichments for Unrestricted and Restricted storage in each region shown in Table 6. This establishes the first part of the total soluble boron credit required without accidents. In addition to the boron credit required to maintain keer 5 0.95, boron credit is also used to compensate for uncertainties associated with the reactivity equivalencing methods. Two reactivity equivalencing methods are used in this analysis; l;. i i ? I i I j

q m Page 15 of 41 burnup credit and IFBA credit. For burnup

credit, the uncertainties associated with this reactivity equivalencing method are as follows:

Burnup Credit Uncertainties Calculated reactivity and depletion versus burnup Measured burnup The BP-pull reactivity increase is not included in the boron credit determination since it is already accounted for in the j burnup limits. Previous analysis for McGuire fuel determined an exposure reactivity bias of 0.0048 Dk at 50 GWD/MTU to be applied linearly versus burnup. However, a more conservative value will be used l which is consistent with other boron credit analyses. A value of l 0.01 Dk at 30 GWD/MTU applied linearly versus burnup will be used l for the calculated reactivity uncertainty. To determine the amount of boron credit required for the uncertainty in the calculation of burnup, the burnup credit reactivity bias is determined for the highest burnup requirement from the fuel storage curves for each region. SIMULATE-3 is then run to iterate on the boron concentration until the kort is equal to the k.gr with no boron, less the burnup credit reactivity bias. The uncertainty on measured burnup is 4%. This is the i measurement uncertainty applied to the 2-D power distribution (Fm). This is conservative because the burnup is simply the power distribution integrated over time.

Thus, to assume a burnup uncertainty of 4%

is to assume the measured power distribution was low 'y 4% for its entire depletion history, when in reality it is low times and high at other times. l l To determine the amount of boron credit required for the j l measurement uncertainty on burnup, the highest burnup requirement from the fuel storage curves for each region is determined. The highest burnup requirement is then reduced by 4%. SIMULATE-3 is l then run to iterate on the boron concentration until the kerr with 4% reduced burnup is equal to the kerr with the highest burnup l (i.e. not reduced) and no boron. l For IFBA

credit, the uncertainties associated with this j

reactivity equivalencing method are as follows: IFBA Credit Uncertainties Manufacturing uncertainty Talculational uncertainty l

r Page 16 of 41 The manufacturing uncertainty applied is a 5% decrease in the B o i loading on the IFBA rods. To determine the amount of boron credit needed for the manufacturing uncertainty on IFBA rods, the highest number of IFBA rods required for storage is determined. CASMO-3 is then run to calculate the keer with B o loading reduced i by 5%. The boron concentration is iterated on until the kerr with the reduced Bo loading is equal to the keer with the normal i . loading and no boron. t The calculational uncertainty applied is a 10% decrease in the number of IFBA rods. To determine the amount of boron credit needed for the calculational uncertainty on IFBA rods, the highest number of IFBA rods required for storage is determined. j In this

case, the IFBA requirements for 4.75 w/o fuel are l

interpolated from the previous IFBA results to determine a l specific number of IFBA rods required, instead of one of the I discrete number of IFBA rod configurations available. This specific number of IFBA rods is ~ reduced by 10% and then rounded down to the nearest number of IFBA rods available. CASMO-3 is I then run to calculate the kerr with this number of IFBA rods. The l boron concentration is iterated on until the keer with the reduced ( number of IFBA rods is equal to the no boron 95/95 maximum design kerr. Note that the IFBA credit uncertainties are only calculated for restricted storage in Region lA since IFBA credit is not used for any other storage limits. The boron credit requirements are summarized in Table 11. I. 3.3 New Fuel Storage Vault Analysis (' The new fuel vaults at the McGuire Nuclear Station are designed exclusively for temporary storage of fresh unirradiated fuel. The ANSI /ANS-57.3 Design Standard simply requires that korg be 1 maintained at less than _ or equal to 0.95 under fully flooded condstions and less than or equal to 0.98 assuming optimum l -moderation. Analysis used to determine kort in these storage i racks must therefore assume maximum allowable fuel enrichments. ~ Criticality control relies strictly on the wide spacing between individual storage locations and a specified upper limit for as-tuilt fuel enrichment. The absence of other factors such as soluble boron, fixed poisons, burnup effects and fission products-makes for a relatively straightforward analysis. The normally dry condition of the fuel vaults ' introduces the possibility of water intrusion. Consequently, full density water flooding was conservatively modeled as a normal condition in this analysis. Other less.likely events which could create low density moderator l

p I Page 17 of 41 conditions (i.e. foaming, misting, etc.) dictated analysis of optimum moderator conditions as an accident condition. Vault criticality analysis is therefore performed as a function of both i enrichment and moderator density. KENO-Va was used to calculate the kert for 4.75 %U-235 nominal enrichment for vault storage. The analysis assumed a 100% cell loading pattern and consequently, no loading pattern restrictions are needed or applicable in the new fuel storage vault. The following assumptions are used in the new fuel storage vault l criticality analysis, l.All fuel designs used, or planned for use, at McGuire were analyzed. This included Westinghouse Standard (STD), l Optimized (OFA) and Performance Plus (PF+) and Framatome Mark BW (MkBW) fuel designs.

2. All calculations are 3-D.

The upper and lower fuel assembly nozzlns are ignored.

3. All fuel is fresh unirradiated.

4. No credit is taken for the spacer grid material.

The calculated wor c-case kort for a fuel assembly with the maximum nominal enrichment of 4.75 %U-235 is: New Fuel Storage Vault Maximum keer = 0.9759 This value was for the Westinghouse Performance Plus fuel design which was the most reactive of all fuel types analyzed. This value also includes geometrical and material uncertainties and biases at a 95 percent probability and a 95 percent confidence level as required to demonstrate criticality safety. The uncertainties considered include: Embedded concrete tolerances Fuel Cage tolerances l As specified in ANSI /ANS 57.3, the maximum korf value in a LWR new l fuel storage vailt shall be less than or equal to 0.98 under l optimum moderate,: conditions and less than or equal to 0.95 under l fully flooded conditions. The analytical result shown above J >ndicates that this criteria has been met. l i L

l l Page 18 of 41 4.0 ACCIDENT CONDITIONS ~ As part of the criticality analysis for the McGuire spent fuel l pools, abnormal and accident conditions are considered to verify that acceptable criticality margin is maintained for all conditions. Most accident conditions will not result in an increase in k.cc of the rack.

However, accidents can be l

postulated which would increase the reactivity of the spent fuel l pool. These accidents must be analyzed to verify acceptable l criticality safety margin exists. Since boron is used to l compensate for reactivity increases as a result of postulated accidents, acceptable criticality safety margin exists if the total boron requirements are less than the normal concentration in the storage pool water. The ~most-severe accident in terms of criticality would be the misloading of an assembly; in particular, misloading the highest reactive assembly allowed in the pool in place of the lowest reactive assembly. This acciant would be the substitution of a l fresh 4.75 w/o assembly with a required filler assembly. Since the SIMULATE-3 models for the McGuire storage racks consist l of a 2x2 array reflected with periodic boundary conditions, the substitution _of a fresh 4.75 w/o assembly for a required filler assembly will be extremely conservative since this accident condition will be infinitely reflected. A more realistic j representation of this accident would be to model a larger array, l ar.d misloading a single assembly near the center of this array. However, since substantial criticality margin exists, the overly conservative 2x2 array will be sufficient. l-Other accidents which could have an_ impact on reactivity in the i spent fuel pool are those that affect the water temperature of the spent' fuel pool. Accidents could be postulated which would either increase or decrease the temperature of the spent fuel pool. Therefore, to bound the range of temperatures of the spent fuel pool

water, the accident analysis considers water temperatures of 32 and 212 F.

j l i The above accident conditions are analyzed and the boron L concentration is iterated upon until the calculated kort is less ( than the. soluble boron credit 95/95 maximum design k.cc. This l boron concentration, combined with the boron concentration for boron credit 95/95 k.ee from Section 32 represents the total credit for boron that is_ required for accident conditions. This total boron requirement-must be less than the normal spent fuel pool boron _ concentration. Note that by combining the boron required for accidents with the l

e-1 Page 19 of 41 boron required to maintain 'keer < 0.95 (i.e. the boron credit i 95/95 maximum design kerr), the accident conditions are imposed on top of the dilution, accident for the total boron requirements. However,_ accident conditions are not assumed with no boron l conditions. This is consistent with previous criticality analysis methodology where the double contingency principle is l applied for accidents. The double contingency principle allows l credit for soluble boron under other abnormal or accident conditions, since only a single accident need be-considered at one time and to not assume the presence of some boron would be a second unlikely event. The difference with the boron credit methodology is

that, for added assurance that sufficient criticality safety margin exists, the dilution of the pool with perfect mixing to 937 ppm is assumed to be a credible event.

The additional boron credit ~ requirements for accident conditions are summarized in Table 11. 1 l I x

r Page 20 of 41 5.0 BORON CREDIT

SUMMARY

This analysis ttkes partial credit for soluble boron in the spent fuel pool for both normal and accident conditions. Boron credit is used to compensate for uncertainties related to reactivity equivalencing and accident conditions. The total boron credit requirements for each region are shown in Table 11. The total boron credit requirements for the entire McGuire spent fuel pool are then the highest values from all regions as follows: Boron Credit Boron Required Available Normal 440 937* Conditions Accident 1170 2 6'f52 Conditions I

• - From dilution analysis 2 - current limit specified in the Core Operating Limits Report l

j

r Page 21 of 41 6.0 REGION INTERFACE RESTRICTIONS Fuel will be stored in four regions of the spent fuel pool according to three different loading configurations. The boundary conditions between these configurations is analyzed to assure that the storage configurations at the boundary do not cause an increase in the nominal kert above the design criteria limit on kerr for the individual regions. This analysis is performed to determine if there is a need for new administrative restrictions at the boundaries. The results of this analysis yield the following region interface restrictions. Region Interface Restrictions Region 1A Unrestricted No restrictions Storage Region 1A Restricted The boundary between Region 1A Restricted Storage Storage and any other region shall be a row of restricted and filler assemblies. That is, the row of all restricted assemblies may be adjacent to a wall, but may not be adjacent to another storage configuration. Region IB Unrestricted No restrictions Storage Region 1B Restricted No restrictions Storage i Region 1B Checkerboard No restrictions Storage Region 2A Unrestricted No restrictions Storage Region 2A Restricted No restrictions Storage Region 2A Checkerboard No restrictions Storage Region 2B Unrestrictea No restrictions Storage Region 2B Restricted The boundary between Region 2B Restricted Storage Storage and any other region shall be a row of only filler assemblies. That is, Region 2B Restricted Storage fuel may be j adjacent to a wall, but may not be adjacent to another storage configuration. Region 2B Checkerboard The boundary between Region 2B i Storage Checkerboard Storage and any other region shall be a row of only filler assemblies. That is, Region 2B Checkerboard Storage fuel may be adjacent to a wall, but may not be adjacent to any other storage configuration. l

E ?.- Page 22 of 41 l 7.O

SUMMARY

OF RESULTS The results of the criticality analysis for the McGuire spent l fuel storage racks indicate that the acceptance criteria for i [ criticality le met; that is kerr < 0.95 including uncertainties. The two region rack design is subdivided within in each region for cells with credit for Boraflex and cells without credit for Boraflex. This analysis' takes credit for soluble boron, partial l credit for Boraflex in Regions lA and 2A, no credit for Boraflex l in Regions 1B and'2B, credit for burnup and credit for IFBA rods. I Each of the' four regions has two storage configurations, . Unrestricted'and Restricted storage. Three regions (Regions 'lB, 2A and 2B) have an additional Checkerboard configuration that allows the most reactive fuel to'be stored. The spent fuel storage limits are summarized in Tables 6 through 10 and Figures 3 through 9. The total boron credit requirements for these configurations in all regions are 440 ppm for normal conditions and 1170 ppm for . accident conditions. Also,- the acceptability of storing the new Westinghouse Performance Plus - fuel design in the new fuel storage vaults is verified. l Page 23 of 41 8.O REFERENCES 8.1 " Westinghouse Spent-Fuel Rack Criticality Analysis Methodology," WCAP-14416-NP-A, Westinghouse Commercial Nuclear Fuel Division, Revision 1, November, 1996. 8.2 " Issuance of Amendments - McGuire Nuclear Station, Units 1 and 2," Amendment Nos. 159 and 141 to Facility Operating Licenses NPF-9 and NPF-17, U.S. Nuclear Regulatory Commission, November 6, 1995. 8.3 Baldwin,

Hoovler, Eng, and Welfare,

" Critical Experiments Supporting Close Proximity Water Storage of Power Reactor Fuel", B&W-1484-7, 7/79. 8.4 Beirman, S.R.,

C3ayton, E.D.,

" Criticality Experiments with Subcritical Clusters of 2.35 and 4.31 wt% 235U Enriched UO2 Rods in Water at a Water to Fuel Volume Ratio of 1.6" PNL-3314, July 1980. 1 8.5 Beirman, S.R. et al, " Critical Separ. tion Between Subcritical Clusters of 2.35 wt% 235U Enriched UO2 Rods in Water with Fixed Neutron Poisons" PNL-2438, October 1977. 8.6 Beirman, S.R., " Criticality Experiments to Provide Benchmark Data on Neutron Flux Traps" PNL-6205, June 1988. l Page 24 of 41 Table 1 CASMO-3/ TABLES-3/ SIMULATE-3 Benchmarking Results Core Soluble Moderator Separation Poison k.f r calc k,r e meas Bias Boron Temp Spacing Sheet (cm) (%B) 2 1037' 18.5 0 n/a 1.00271 1.0001 -0.00261 3 764 18 1.636 n/a 1.00319 1.0000 -0.00319 9 0 17.5 6.544 n/a .99908 1.0030 0.00392 10 143 24.5 4.908 n/a .99795 1.0001 0.00215 11 514 26 1.636 SS 1.00493 1.0000 -0.00493 13 15 20 1.636 1.614 1.00914

1. 0000

-0.00914 14 92 18 1.636 1.257 1.00451 1.0001 -G.00441 15 395 18 1.636 0.401 .99608 0.9988 0.00272 17 487 17.5 1.636 0.242 .99889 1.0000 0.00111 19 634 17.5 1.636 0.1 1.00003 1.0002 0.00017 avg 1.00165 st.dev 0.00412 kg,cale cale avg k,,, 1.00023 avg bias -0.00142 meas CASMO-3/ TABLES-3/ SIMULATE-3 Methodology Bias = -0.00142 CASMO-3/ TABLES-3/ SIMULATE-3 Methodology Uncertainty 0.01199 = l l Page 25 of 41 Table 2 KENO-Va Benchmarking Results 1 Exp. Calculated Exp. Calculated Report Number kort std dev Report Number k.cr std dev ~ PNL-3314 043 0.99991 0.00* 3 PNL-3314 085 0.98979 0.00354 PNL-3314 045 0.9984 0.00.35 PNL-3314 094 0.99568 0.00383 PNL-3314 046 0.9999 0.0033 PNL-3314 095 0.99914 0.004 PNL-3314 047 1.00532 0.00346 PNL-3314 096 0.99908 0.00349 PNL-3314 048 1.00083 0.00326 PNL-3314 097 0.99731 0.00342 PNL-3314 04c 0.99727 0.00317 PNL-3314 098 0.99494 0.00353 PNL-3314 051 1.00114 0.00392 PNL-3314 100 0.99621 0.00378 PNL-3314 053 0.99105 0.0035 PNL-3314 101 0.99799 0.00391 PNL-3314 055 0.99502 0.00409 PNL-3314 105 0.99911 0.00339 PNL-3314 056 0.99249 0.0038 PNL-3314 106 0.99323 0.00353 PNL-3314 057 0.99603 0.00317 PNL-3314 107 0.99812 0.00302 PNL-3314 058 0.99613 0.00321 PNL-3314 131 0.99708 0.00379 PNL-3314 059 0.99233 0.00377 PNL-3314 996 1.0115 0.00304 PNL-3314 060 0.99657 0.00362 PNL-3314 997 1.00775 0.00305 PNL-3314 061 0.99331 0.00371 PNL-2438 005 0.9923 0.00348 PNL-3314 062 0.9954 0.00418 PNL-2438 014 0.99212 0.00321 PNL-3314 064 0.98736 0.00351 PNL-2438 015 0.99207 0.00301 PNL-3314 065 0.99728 0.00392 PNL-2438 021 0.99119 0.00302 ^ PNL-3314 066-0.9942 0.00374 PNL-2438 026 0.99218 0.00314 PNL-3314 067 0.99153 0.00374 PNL-2438 027 0.99396 0.00312 PNL-3314 068 0.99169 0.00333 PNL-2438 028 0.99092 0.00322 ' PNL-3 314 069 0.99684 0.00396 PNL-2438 029 0.99366 0.00319 PNL-3314 06d 1.00645 0.004 PNL-2438 034 S.99596 0.00323 PNL-3314 070 0.98921 0.00?69 PNL-2438 035 0.98911 0.00317 j PiTL-3314 071 0.99405 0.00342 PNL-6205 214 0.99117 0.00353 PNL-3314 072 0.98865 0.00356 PNL-6205 223 0.99726 0.0038 PNL-3314 073 0.98891 0.00343 PNL-6205 224 0.99329 0.00388 PNL-3314 083 0.99043 0.00341 PNL-6205 229 1.00119 0.00355 PNL-3314 084 0.99366 0.00364 PNL-6205 230 1.00031 0.00406 Average kore = 0.99559 l KENO-Va Methodology Bias = 0.00441 l l KENO-Va Methodology Uncertainty 0.00739 = l L_ Page 26 of 41 Table 3 l CASNO-3 / SIMULATE-3 / KENO Va Comparisons Fuel Fuel CASMO Simulate KENO Rack Region Enrichment Type k,rr kor t k,t r MNS Region 1A 4.0 mbw .97661 .976666 .96827 (25% of original Boraflex) MMS Region 1B 4.0 mbw 1.18568 1.185535 1.17930 (No Boraflex) MNS Region 2A 1.4 mbw .93033 .930428 .92877 (50% of original Boraflex) MNS Region 2B 1.4 mbw 1.06701 1.06701 1.06233 j (No Boraflex) 1

i Page 27 of 41 Table 4 No Boron Biases and Uncertainties for Fresh Fuel J Region Region Region Region Bias or Uncertainty 1A 1B 2A 2B Methodology Bias' -0.00142 -0.00142 -0.00142 -0.00142 Boraflex Width Shrinkage Bias 0.005405 0 0.00202 0 Self-Shielding Bias 0.002141 0 0.000712 0 95/95 Methodology Uncertainty 0.01199 0.01199 0.01199 0.01199 Boraflex Axial Shrinkage 0.002595 0 0.00010 0 Uncertainty Mechanical Uncertainty 0.015923 0.018729 0.007877 0.010993 Combined Bias and Uncertainty 0.027647 0.022238 0.017178 0.016267 No Boron 95/95 Maximum Design 0.972353 0.977762 0.982822 0.983733 k.er Combined Bias and Uncertainty: Ak = Ak.m + Ak,o,s + n,ss iom, + #e.,su.c + C.,.i + W.<su.c u w sei n 4 u

• Negative bias conservatively ignored l

l

I Page 28 of 41 ( Table 5 l Boron Credit Biases and Uncertainties for Fresh Fuel l l . Bias or Uncertainty Region Region Region Region 1A 1B 2A 2B l Methodology Bias' -0.00142 -0.00142 -0.00142 -0.00142 l Boraflex Width Shrinkage Bias 0.005405 0 0.00202 0 Self-Shielding Bias 0.002141 0 0.000712 0 95/95 Methodology Uncertainty 0.01199 0.01199 0.01199 0.01199 Boraflex Axial Shrinkage 0.002595 0 0.00010 0 Uncertainty Mechanical Uncertainty 0.015912 0.019684 0.008545 0.010922 Combined Bias and Uncertainty 0.027638 0.023049 0.017556 0.-016266 No Boron 95/95 Maximum Design 0.922362 0.926951 0.932444 0.933734 k.rr Combined Bias and Uncertainty: Ak = Ak ,,33,,, + M w,a,, + M,,,sn io,,, + MPucinunc + MAxial + MechUne u s

• Negative bias conservatively ignored

) 1 f 1

( Page 29 of 41 Table 6 Summary of Maximum Fresh Fuel Enrichment Limits (w/o U-235) Type of Storage Region Region Region Region 1A 1B 2A 2B Unrestricted 3.78 1.78 1.61 1.11 Restricted 4.75 2.20 2.12 1.22 Filler 1.76 1.45 1.20 1.08 Checkerboard N/A 4.75 4.75 4.75 l l l

i Page 30 of 41 ( Table 7 Minimum Qualifying Burnup<versus Initial Enrichment l For Unrestricted Storage Region IA Region IB Region 2A Region 2B j initial Minimum Initial Minimum Initial Minimum Initial Minimum Enrichment Burnup Enrichment Burnup Enrichment Burnup Enrichment Burnup (w/o U-235)) (GWD/MTU) (w/o U-235)) (GWD/MTU) (w/o U-235)) (GWD/MTU) (w/o U-235)) (GWD/MTU) 3.78 0.00 1.78 0.00 1.61 0.00 1.11 0.00 4.00 1.58 2.00 3.96 2.00 7.79 2.00 21.58 4.50 4.92 2.50 11.35 2.50 15.14 2.50 29.00 4.75 6.66 3.00 17.61 3.00 21.45 3.00 35.69 3.50 23.35 3.50 27.42 3.50 41.97 4.00 28.86 4.00 33.00 4.00 47.90 4.50 34.10 4.50 38.32 4.50 53.57 4.75 36.67 4.75 40.91 4.75 56.33 l Table 8 Minimum Qualifying Burnup versus Initial Enrichment For Restricted Storage Region I A Region IB Region 2A Region 2B Initial Minimum Initial Minimum Initial Minimum Initial Minimum Enrichment Burnup Enrichment Bumup Enrichment Bumup Enrichment Burnup (w/o U-235)) (GWD/MTU) (w/o U-235)) (GWD/MTU) (w/o U-235H (GWD/MTU) (w/o U-235)) (GWD/MTU) 4.75 0.00 2.20 0.00 2.12 0.00 1.22 0.00 2.50 3.91 2.50 5.10 2.00 17.55 3.00 9.65 3.00 10.88 2.50 24.73 3.50 15.08 3.50 16.19 3.00 31.31 4.00 19.87 4.00 21.07 3.50 37.40 4.50 24.68 4.50 25.81 4.00 43.15 l 4.75 27.01 4.75 28.11 4.50 48.65 4.75 51.33 Table 9 Minirc.um Qualifying Burnup versus Initial Enrichment For Filler Assemblies l I Region IA Region IB Region 2A Region 2B Initial Minimum Initial Minimum Initial Minimum Initial Minimum Enrichment Burnup Enrichment Burnup Enrichment Burnup Enrichment Burnup (w/o U-235)) (GWD/MTU) (w/o U-235)) (GWD/MTlh (w/o U-235)) (GWD/MTU) (w/o U-235H (GWD/MTU) 1.76 0.00 1.16 0.00 1.20 0.00 1.08 0.00 2.00 5.12 2.00 12.68 2.00 19.80 2.00 23.I4 2.50 13.57 2.50 20.17 2.50 27.64 2.50 30.59 3.00 19.80 3.00 27.03 3.00 34.56 3.00 37.42 3.50 25.85 3.50 33.35 3.50 41.08 3.50 43.74 4.00 31.50 4.00 39.33 4.00 47.25 4.00 49.72 4.50 36.93 4.50 45.07 4.50 $3.15 4.50 55.49 j 4.75 39.54 4.75 47.89 4.75 56.01 4.75 58.33 I i

E i l Page 31 of 41 I Table 10 Summary of IFBA Credit Requirements Number of Maximum Fresh Fuel IFBA Rods Enrichment l For Unrestricted Storage 0 3.78 i 16 4.22 32 4.56 48 4.89 1 I 1 I 1 i l i l l l l

61 4 tnf 0 0 0 0 0 0 eo B 0 8 6 0 00 600 7 2 0 m 2 6 1 1 7 1 3 1 h2 c3 at e r tg le 0 0 0 0 0 0 Aa iA 0 3 l 4 2 00 30 0 7 0 P F2 4 2 1 2 1 7 4 1 / 1 w d e tc i B 0 0 0 0 0 r 00 0 t e1 62 00 7 0 7 4 1 s 6 2 1 3 1 2 6 R 0 0 0 0 0 0 A 0 3 0 00 00 0 7 4 4 1 1 1 s 3 1 3 1 4 7 tne me 0 r 8 0 00 0 0 0 4 6 2000 600 7 8 i 2 1 1 1 1 7 1 3 u 1 q eR 0 t 0 0 0 0 A 00 0 4 1i d 2 99 00 30 7 1 3 2 1 1d e 2 7 1 4 1 t e er ic r t lC s b e r an n 0 0 0 0 0 To UB 6 00 7 0 7 5 2 00 0 r 1 54 2 1 3 1 2 6 oB f o A 0 0 0 0 0 0000 3 2227 00 0 1 7 4 4 y 1 1 3 1 4 7 r a m m u s s t S t d p n n u e e d p a r d i e e mc lo u k t ic c a a c c am w A A t c un n e 5 b u u h y n o h 0 eal lan y w i t 9 d n c c i / w s r a d me s d d s cumc a g a e e r ns r uaAA o o r r f e inu ib m le iu iu e g EBB tsn f g q q cb MIFF I mae n e e k r nr r r r r r r is R R o e oooo sooo ioddd o d it t f f f f nf f f r i d f ladddd d f v eee e e e ieeee r r r r it d r r r r r r uiiii diii e C C iu quuuu nuuu r 5 q Eqqqq oqqq i n n u e eeee ceee r yr r r r r r r q o o 9 r r t t e o o 0 n innnn nnnn r v oooo eooo B B 5ro it r r r r d r r r n c f o a oooo iooa o l l a a f c r t t eB eBBBB cBBB o o o -k R A B T T

i Page 33 of 41 Figure 1 McGuire Fuel Pool Layout with Region 1 Detail REGION 1 REGION 2 . g; iin i. .i!!

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ii. !!,J L ?!it!!?! k' h t 12 X 16 I," di.$- e4-. r E E' j .. J ;;;! :/ i b 1 L. Page 35 of 41 Figure 3 3 out of 4 Restricted Storace Pat;;srn for Region 1A .r - m JI N.0;;f .ga.: 'l:: !(- }. .. u. w-: r T. - 'k' i. o\\. ,. o;, Q, ' s, - i l 51 y: ) 9N e/ t. e e c2 1 Restricted !O Filler Fuel $N Fuel Fuel Storage Cell Page 36 of 41 Figure 4 l 2 out of 4 Restricted Storage Pattern for Regions 1B and 2A [l 'p)[5;$5I) 3:;;

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