Text

Nuclear Design Analysis Rept for Facility Spent Fuel Storage Racks
	ML19319D199
Person / Time
Site:	Crystal River
Issue date:	03/08/1978
From:	Buck P, Hussin J, Van Kessel T; NUCLEAR ENERGY SERVICES, INC.
To:	;
Shared Package
ML19319D195	List: ML19319D194; ML19319D199; ML19319D200;
References
	5127, NES-81A0521, NES-81A521, NUDOCS 8003130792
	Download: ML19319D199 (37)
	v • d • e

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NES 81A0521 U^

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NUCLEAR DESIGN ANALYSIS REPORT FOR THE CRYSTAL RIVER UNIT 3 SPENT FUEL STORAGE RACKS Prepared Under NES Project 5127 NUCLEAR ENERGY SERVICES, INC.

Danbury, Connecticut 06810 A

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TABLE OF CONTENTS Page 1.

SUMMARY

1-1

'2.

INTRODUCTION 2-1 3-1

3., DESCRIPTION OF SPENT FUEL STORAGE RACKS 4.

CRITICALITY DESIGN CRITERION AND CALCULATIONAL ASSUMPTIONS 4-1 4.1 Criticality Design Criterion.

4-1 4.2 Calculational Assumptions 4-1

~~

s.

CRITICALITY CONFIGURATIONS 5-1 5.1 Normal Configurations 5-1 5.1.1 Reference Configuration.

5-1 5.1.2 Eccentric Configurations 5-1 5.1.3 Fuel Assembly Tolerances 5-2 5.1.4 Fuel Design Variation.

5-2 5.1.5 Fuel Rack Cell Pitch Variation 5-2 5.1.6 Fuel Rack Cell Wall Thickness Variation.

5-2 5.1.7 Low Boron Content in Poison Sheets 5-2 5.1.8

" Worst Case" Normal Configuration 5-2 5.2 Abnormal Configurations 5-3 5.2.1 Fuel Handling Incident 5-3 5.2.2 Pool Temperature Variation 5-3 5.2.3 Fuel Drop Incident 5-3 5.2.4 Seismic Event.

5-3 5.2.5

" Worst Case" Abnormal coni _guration.

5-4

- 6.

CRITICALITY CALCULATION METHODS 6-1 6.1 Method of Analysis 6-1 6.2 Benchmark Calculation for Diffusion 6-1 Theory.

6.3. Code Descriptions 6-2 6.3.1 The HAliMER Code 6-2 6.a.2 The EXTERMINATOR Code.

6-2 6.3.3 the KENO Code.

6-2 D

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Page 7.

RESULTS OF CRITICALITY CALCULATIONS 7-1 7.1 Cross sections from RAMMER 7-1 7.2 Two Dimensional Diffusion Theory Calculations - EXTERMINATOR.

7-2 7.3 K,ff Values for Normal Calculations 7-2 7.3.1 Reference Configuration.

7-2 7.3.2 Eccentric Configurations 7-2 7.3.3 Fuel Design Variation.

7-2 7.3.4 Fuel Rack Cell Pitch Variations.

7-2 7.3.5 Boron Concentration variation.

7-3 7.3.6

" Worst Case" Normal Configuration.

7-3 7.4 Keff Values for Abnormal Configurations 7-3 7.4.1 Fuel Pool Temperature Variation.

7-3 7.4.2

" Worst Case" Abnormal Configuration.

7-3 Monte Car'o Calculation for l

'7.5 Reference Configuration 7-4 7.6 Effects of Calculational Uncertainty.

7-4 8.

REFERENCES 8-1 e

,m 9

iii

O 4

LIST OF TABLES Page i

7.1 Parameters of 15 x 15 nahrvv-k & WilcDXFuel Assemblies 7-5 7-6 7.2 HAMMER Input Data.

7-7 7.3. Four Group IUuctER Cross Sections for Fuel Regions.

7.4 EXTERMINATOR Input, Reference Configuration.

7-9 7.5 Parameters and Results of EXTERMINATOR 7-13 Calculations LIST OF FIGURES P_ age _

3-2 3.1 Crystal River-PWR 6 x 6 Fuel Storage Rack.

5.1 Fuel Assembly Eccentrically Positioned 5-5 Within Storage Cell.

5-6 5.2 Eccentrically Positioned Storage Cell.

6-3 6.1 Typical Fuel Storage Location.

7.1 HAMMER Model for Fuel Rod and Guide Tubes with Associated Water Regions 7-14 7.2 RAMMER Model for Poison Wall 7-15 7-16 7.3 AKeff Vs. Enrichment 7-17 7v4--AKef f-Vs.-Water Temperature 7-18

' 7.5 AKeff Vs. Water Density.

7.6 AKeff Vs. Pitch...

7-19 7.7 AKeff Vs. 310 Concentration.

7-20 Vs. Stainless Steel Wall Thickness 7-21 7.8 AKeff h

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1.

SUMMARY

A detailed nuclear analysis has been performed for the NES design for spent fuel storage racks for Crystal River Unit 3.

The racks, which use B C poison sheets for criticality control, have been 4

shown oy this analysis to meet the criticality criterion of< 0.95 for 3.3 w/o lhb::ock & Wilcox 15 x 15 fuel assemblies for all anticipated normal and abnormal configurations.

Certain conservative assump-tions about the fuel assemblies and racks have been used in the calculations.

The normal configurations considered in the nuclear analysis include the reference configuration (an array of square boxes spaced 10.5 inches on centers with centrally positioned fuel), the eccentric positioning of fuel within the storage boxes

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and the variations permitted in fabrication of the principal fuel rack dimensions and in poison concentration.

The abnormal config-uraficns included box displacement, spent fuel pool temperature variations and fuel handling incidents.

The principal calculational method used for the criticality analysis was diffusion theory.

Cross sections were determined through use of the HAMMER code and keff was determined by EXTERMINATOR, a multi-group, two-dimensional diffusion theory code.

Calculations have been performed with the KENO Monte Carlo code to establish a Monte Carlo /

diffusion theory bias.

The keff value calculated by diffusion theory for the reference configuration is 0.8819 and when combined with the Monte Carlo /dif-fusion theory bias becomes 0.9074.

Combining the variations in keff due to the other normal configurations yields a resulting keff of 0.9168.

The keff value for the " worst case" abnormal configuration is 0.9313, only slightly greater than the " worst case" normal config-uration.

If a value of +0.01 is assumed for the calculational uncer-tainty and combined statistically with the normal variations, the resulting keff for the " worst case" abnormal configuration is 0.9356.

This value meets the criticality design criterion and is substantially below 1.0.

Therefore, it has been concluded that the Crystal River Unit 3 high density storage racks when loaded with the specified fuel are safe from a criticality standpoint.

l 1-1

2.

INTRODUCTION The NES final design for high density fuel storage racks for Crystal River Unit 3 consists of a 6 x 6 square array of storage boxes B C sheets 0.075" thick are placed between spaced 10. 5" on centers.

4 two 0.060" stainless steel sheets to comprise the box wall.

Pgison content within the B C plates will be a minimum of 0.012 gm/cm 4

B 0, which results in an atom density of 0.00379 1

(areal density) atoms /b-cm B10, A detailed nuclear design has been performed to assure that the NES high density storage racks, when loaded with fresh fuel of the highest enrichment available at Crystal River Unit 3, will have a keff substantially below 1.0 for all anticipated normal and abnormal configurations of fuel assemblies and racks.

Certain conservative assumptions have been made in the analysis.

These assumptions and the criticality design criterion are described in Section 4.

The reference configuration forms the basis for criticality calcu-lations.

This reference configuration consists of a 6 x 6 square array of boxes, each of nominal dimensions, at 68* F, containing fresh fuel centrally located, and with minimum amounts of poison and steel in the walls.

The fuel assemblies are assumed to be 15 x 15 mhrmk & Wilcoxassemblies.with.3.3 w/o average enrichment.

Variations of all important parameters sere separately studied in order to determine the effect on keff of all normal and abnormal deviations from the normal condition.

Included among the variations studied are:

changes in the spacing between the boxes, differences in the amount of boron within the box wall, changes in temperature, change of fuel enrichment, and changes in positioning of fuel assemblies and boxes.

These variations and their effects on kegg are described in' detail in Section 5.

The principal calculational method used for the criticality analysis

. was diffusion theory.

Cross sections were determined through use of the HAMMER code and kef f was determined by EXTERMINATOR, a multigroup, two-dimensional dif fusion theory code.

Verification calculations have been performed with KENO, a Monte Carlo code.-

A detailed des-cription of the calculational method and the computer codes is presented in Section 6.

A benchmark calculation using diffusion theory is also discussed in Section 6.

The results of the criticality analysis are presented in Section 7.

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3.

DESCRIPTION OF SPENT FUEL STORAGE RACKS Each storage rack contains 36 storage locations spaced 10.5" on centers.

(See Figure 3.1)

Each location consists of a box of 8.937" I.D.

and 171.625" tall whose wall is a composite material consisting of a 0.075" poison plate sandwiched between two 0.060" (mi-nimum) 304 stainless steel sheets.

The poison plate consists of B C (boron carbide) within a binding material.

The B10 areal 4

density within the plate is 0.012 gm/cm2 minimum.

Each plate is 6.687" wide.

The walls of the box are held at the edges by 1 1/4" x 1/8" stainless steel angles.

Between boxes is a 0.586" water gap.

Spacer grids and clips are provided to maintain center to center spacing at 10.5".

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CRITICALITY DESIGN CRITERTON AND CALCULATIONAL ASSUMP2 IONS 4.1 Criticality Design Criterion A satisfactory value of k,gf for a spent fuel pool involves con-siderations of safety, licensability, and storage capacity requ.f.re-mints.

These factors demand a kog, substantially below 1.0 for safety and licensability but high enough to achieve the required storage capacity.

The published position of NRC on fuel storage criticality is presented in Section 9.1. 2 of the NRC Standard Review Plan (Reference

1) which states the following:

" Criticality information (including the associated assumptions and input parameters) in the SAR must show that the center spacing between assemblies results in a suberitical array.than about 0.95 for this condition i,ff of less Ak s acceptable."

Furthermore NRC,' in evaluating the design, will " check the degree of suberiticality provided, along with the analysis and the assumptions".

On the basis of. this information, the following criticality design criterion has been established for the Crystal River Unit 3 high density fuel storage racks:

"The multiplicatinn constant (kefg) shall be less than 0.95 for all normal and abnormal configurations as confirmed by Monte Carlo calculation."

4.2 Calculational Assumotions The following conservative assumptions have been used in the criti-cality calculations performed to verify the adequacy of the rack design with respect to the criticality design criterion:

1.

The pool water has no soluble poison.

2.

The fuel is fresh and of the highest enrichment of any fuel available.

3.

The reference configuration contains an infinite array of storage locations.

This is obviously conservative because the array is, of course, finite.

4-1

5.

CRITICALITY CONFIGURATIONS To assure that the keff of the Crystal River Unit 3 racks is suitably below 0.95 for all conditions, several normal and abnormal criti-cality configurations were studied in addi'. ion to the reference configuration.

Normal configurations are considered to be those which can result from allowed tolerances in spacing or thickness of rack components, tolerances in fuel ~ assembly manufacture, tolerances in poison content, and from the positioning of fuel assemblies within storage locations.

Abnormal conditions are those conditions resulting from accident or nalfunctions such as a fuel assembly, drop onto the rack, a seismic event, an increase in fuel pool temperature due to loss of cooling, etc.

This section describes the normal and abnormal configurations considered in this analysis.

5.1 Normal Configurations 5.1.1 Reference Configuration The reference configuration consists of an infinite array of storage cells spaced 10.5" on centers. (See Figure 3.1)

In each storage cell is a 15 x 15 Ihbasck & Wilcoxfuel assembly with an average enrich-ment of 3.3 w/o centrally located within the storage cell.

Each storage cell is represented by a box of 8.937"2 I.D.

and wall thick-ness of.195".

Poison content is 0.012 gm/cm (areal density)

B10 in 6.687" wide by 0.075" thick B C plates.

The poison plates 4

are between two 0.060" 304 stainless steel plates.

The temperature of the fuel pool is 68' F for the reference config-uration.

5.1.2 Eccentric Configurations Eccentric positioning of fuel within the storage cell is represented by a worst case configuration in which 4 adjacent assemblies are brought as close as possible to each other within their storage cells. (See Figure 5.1)

Eccentric positioning of a storage cell in the event of a mounting clip failure is repre'sented by the displacement of adjacent rows of cans the maximum amount allowable by the physical structure of the rack, this amount being approximately 0. 25".

(See Figure 5.2) 5-1 l

+*

A 5.1.3 Fuel Assembly Tolerances.

- The important fuel assembly parameter determining k,ff is the ratio of the amount of U235 to that of water.

The amount of U235 per assembly is controlled to within a few tenths of a percent by weighing pellet stacks as the fuel is built and by using a known enrichment.

The fuel assembly parameter which determines the volume of water in an assembly is the clad O.D.

This parameter is closely controlled to typically.within 10.4 percent.

The effects of these two fuel assembly tolerances on keff have been determined to be.

negligible on the basis-of simple k = cell calculations.

Conseq'uently, fuel assembly tolerances were not considered further in this analysis.

5.1.4 Fuel Design Variation Calculations have been performed to determine the sensitivity of k

to changes in fuel enrichment ranging from 3.1 w/o to 3.5 ff w o.

5.1.5 Fuel Rack Cell Pitch variation Calculations were performed to determine the sensitivity of k,f, ions.

to changes in the center to center spacing between storage locat The pitch was varied from 10.25 to 10.75 inches.

5.1.6 Fuel Rack Cell Will Thickness Variation Determination of keff sensitivity to variation in stainless steel thickness was performed by adding and subtracting 0.010" to each of the two sheets which compose the wall, resulting in an overall thickness variation from 0.175" to 0. 215 ".

5.1. 7 Low Boron Content in Poison Plates Variation of poison concentration was egmined over a range of i 10% corresponding to a variation of B atom density within the plates from 0.00341 atoms /b-cm to 0.00416 atoms /b-cm.

5.1.8

" Worst Case" Normal Configuration The " worst case" configuration combines the adverse effects of eccentric fuel positioning, low boron content, and fuel rack manufacturing tol-erances.

t 5-2

5.2 Abnormal Configurations 5.2.1 Fuel Handling Incidents Two fuel handling incidents were considered.

The first involves eccentric placement of assemblies within the peripherally located failed fuel storage cans.

Structure will be provided to ensure that only the correct (centered) and deliberate placement is pos-s'ble.

The second incident involves placement of a fuel assembly i

al'ng the side of the rack.

Structure will be provided to prevent o

the accidental placement of fuel closer than 6" from the side of the rack.

Calculations have been performed to determine the change in keff with an assembly 6" from the rack.

5.2.2 Pool Temperature Variation Calculations were performed to determine the sensitivity of keff for the reference configuration to variations in the spent fuel pool temperature.

The pool temperature was varied from 39' F, where water density is a maximur.

to 260' F, the approximate boiling point of water near the botte, of the fuel rack.

5.2.3 Fuel Drop Incident If a fuel assembly should be dropped on the spent fuel storage rack, it would most probably strike the top'of a stored fuel assembly since these assemblies project several inches above the tops of the cans.

The damage would probably be confined to the uppermost part of the assembly (above the active fuel region) and consequently the effect on keff would be nil.

Even if the fuel assembly were axially compressed, no increase in keff would be expected; a unit cell calculation based on an axial compression of 2 feet yielded a 0.06 decrease in km of the fuel cell.

It has been concluded, therefore, that this incident i

would reduce keff and need not be considered further in this analysis.'

i 5.2.4 Seismic Incident SeismAc analyses have determined that during an SSE the pitch be-tween two adjacent fuel assemblies could narrow locally by as much as. 021 inches, due to oscillations about nodal points determined by the structural members locating the cells within the racks.

How-ever, at the same time, the local pitch at other locations is greater by the same amount, with the net effect that although the pitch may vary locally, the average pitch is unaffected.

t 3-3

5.2.5

" Worst Case" Abnormal Configuration abnormal configuration considers the effect of the The " worst case" most adverse abnormal condition in combination with the " worst case"

- normal configuration.

The results for the " worst case" abnormal configuration are presented in Section 7.4.

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ILLUSTRATION 07 ECCENTRICALLY LOCATED FUEL CONFIGURATION USED IN EXTERMINATOR CALCULATIONS FOR THE CRYSTAL RIVER UNIT 3 SFENT FUEL STORAGE RACES i

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ILLUSTRATION OF ECCENTRICALLY FOSITIONED STORAGE CELL CONFIGURATION USED IN EXTERMINATOR CALCULATIONS FOR CRYSTAL RIVER UNIT 3 SFENT FUEL STORAGE RACKS I

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6.

CRITACILITY CALCULATION METHODS 6.1 Method of Analysis For each of the normal and abnormal configurations discussed in the keff was determined from a two dimensional diffusion Section 5, theory calculation of an infinite array of fuel storage racks.

An infinite array is used because such an array can be represented by a small repeating portion with suitable reflecting boundary Figure 6.1 shows a representation of a complete stor-conditions.

age location with the boundary conditions necessary to represent an infinite array.

Use of an infinite array results in a conservative value of k gg for e

a_ rack in which the array is obviously finite.

The effect on kegg of buckling in the vertical direction was cal-culated from a knowledge of average fuel properties and of the compo-sition of the reflector regions above and below the active regions of the fuel assemblies.

The diffusion theory calculations have been performed using the 2-D diffusion theory code EXTERMINATOR with cross section input determined by the HAMMER code.

Normally for criticality calculations dealing diffusion theory gives very satisfactory results since with reactors, the codes and cross sections have been normalized to fit experimental data over many years.

For calculating the effect of lumped poisons such as the B C sheets, 4

blackness theory was used for determination of cross sections.

Backup calculations for diffusion theory were performed using the 3-D multigroup Monte Carlo criticality code, KENO.

6.2 Benchmark Calculation for Diffusion Theory Both HAMMER and EXTERMINATOR are used by NES as versions available at Combustion Engineering at Windsor Locks, Connecticut.

The combina-tion has been benchmarked against a cold critical experiment per-formed at the Lacrosse Boiling Water Reactor with excellent results dif fered from the experi-l (see Reference 2).

The calculated keff mental value by only 0.0017.

1

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O A-1

6.3 Code' Descriptions 6.3.1 The HAMMER Code HAMMER (see Reference 3) is a multigroup integral transport theory code which is used to calculate lattice cell cross sections for diffusion theory codes.

This code has been extensively benchmarked against D 0 and light water moderated La ttices with good results.

2 6.3.2 The EXTERMINATOR Code is a 2 D multigroup diffusion theory EXTERMINATOR (see Reference 4)

- code used with input from HAMMER to calculate k,ff values.

6.3.3 The KENO Code KENO is a 3-D multigroup Monte Carlo criticality code used to deter-mine keff (see Reference 5).

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6-3

I 7.

RESULTS OF CRITICALITY CALCULATIONS Four group cross sections were determined by means of the HAMMER code for the criticality configurations to be evaluated.

These cross sections were then used in the two dimensional diffusion theory code EXTERMINATOR to determine kegg.

The effects of normal and abnormal variations were evaluated where necessary by performing separate EXTERMINATOR problems for each 1

criticality configuration.

A check upon the diffusion theory method was made by per' forming an entirely-separate calculation of the reference configuration using

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KENO.

KENO contains its own library of 16-group Hansen-Roach X-sections which were used in the reference case Monte Carlo cal-culation.

7.1 Cross Sections from HAMMER The RAMMER input for fuel regions was based on the description of the 15 x 15 mWk & Wi.lcox fuel assembly presented in Reference 6.

The properties of the fuel assembly pertinent to the nuclear cal-culations are summarized in Table 7.1.

Figure 6.1 presents the model of the 15 x 15' assembly used in the calculations.

The basic region considered in a HAMMER problem is a fuel ro'd including pellets, clad, and the associated water in the area surrounding the rod.

The total area is a square with the dimension of one rod pitch.

(See Figure 7.1).

The HAMMER model of the poison wall is shown in Figure 7.2.

The resulting homogeneous wall X-sections were used in conjunction with the Group 3 & 4 blackness theory cross sections to accurately rep-resent the poison wall.

The wall configuration can be seen in Figure 6.1.

~ A HAMMER problem was written to represent each vari.ition in fuel cell characteristics:

enrichment, temperature and 'roid content.

Mac2ascopic cross sections for stainless steel, boron, water and zircsnium were determined from microscopic cross sections derived fron the RAMMER calculations.

The fuel was assumed to occupy the total volume inside the clad including the gap; the correct amount of fuel was determined ~from the fuel loading information.

The input dimensions and atom densities used for the various fuel cell cal-culations are listed in Table 7.2.

The resulting four group cross sections for fuel regions are summarized in Table 7.3.

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7-1

7.2 Two Dimensional Diffusion Theorv Calculations - EXTERMINATOR The geometry layout and material labels used for the reference con-

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figuration are shown in Table 7.4.

The cross sections for each fuel enrichment, for water, and for the poison wall were chosen from the appropriate four group cross sections determined by HAMMER.

The cross sections-for the boron were determined from blackness theory.

The cross section input and mesh spacings used for the referenced EXTERMINATOR configurations are listed in Table 7.4.

Table 7.5 presents the resulting Akef,f value for each calculation.

7.3 Keff Values for Normal Configurations

'7.3.1 Reference Configuration The k gg for the reference configuration described in Section 5.1.1 e

was determs.ned to be 0.8819 by means of HAMMER / EXTERMINATOR.

7.3.2 Eccentric Configurations The Akeff for the first eccentric configuration described in Section 5.1.2 (four assemblies displaced diagonally towards each other the maximum amount. allowed by clearances) was determined to be -0.0029.

The Akeff due to displaced cans along rows is +0.0055 in the worst Case.

7.3.3 Fuel Design Variation Fuel enrichment was varied from 3.1 w/o to 3.5 w/o and Ak,, =

+0.0121 @3.5 w/o with the base case being 3.3 w/o.

3.3 wfo^is the highest enrichment to be used in the rack, therefore no allowance need be made for fuel enrichment variation.

7.3.4 Fuel Rack Cell Pitch Variations

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The average cell pitch was varied from the reference spacing plus and minus 0.25" and resulted in Akeff = +0.0304 @l0.25" average cell pitch and Akeff-= -0.0264 010.75" average cell pitch.

The nominal cell pitch is 10.5"; it is estimated that this dimension will be maintained within +1/16" with a resulting change in keff of +0.0076.

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7-2

7.3.5-Boron Concentration Variation The boron concentration was varied plus and minus 10% resulting 10 in corresponding Ak's of

. 0 010 and +0. 0014.

Since the minimum 3 content allowed by mgnufacture is equal to the base case areal 0/cm2, no allowances will be taken for its density of 0.012 gmB variation.

7.3.6

" Worst Case" Normal Configuration The keff for the " worst case" normal configuration can be determined from the kef f for the reference case and the variations determined above.

Reference Case keff:

0.8819 Eccentric Positioning Fuel:

negative Cell Pitch Decrease:

+0.0076 Displaced Box:

+0.0055

0. 8819 t '!0. 00762 + 0.00552 Therefore keff

=

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0.0094.

=

The resulting keff for the " worse case" normal configuration is 0.E913.

7.4 Keff Values for Abnormal Configuration The abnormal configurations described in Section 5.2 include. fuel handling incidents, variation in fuel pool temperature, a fuel assembly drop onto the rack and a seismic event.

7.4.1 Fuel Pool Temperature Variation The variation of kegg with fuel pool temperature is shown in Figure 7.4.

For temperatures above 68* F Akeff is negative.

At (maximum H O density) Akeff = +0.0112.

. 39* F 2

7.4.2

" Worst Case" Abnormal Configuration Lowering fuel pool temperature to 39* F results in a Ak of +0.0112.

Dropped fuel 6.0" from the rack will result in a Ak of +0 0032 which when added together gives a Ak of 40.0145.

Other abnormal con-figurations are negligible.

The final kegg value taking account of abnormal configurations is:

keff = 0.9058.

7-3 l

7.5 Monte Carlo Calculation for Reference Configuration A Monte Carlo calculation was performed using KENO to establish the bias between Monte Carlo and diffusion theory in order to compensate for the inaccuracies of diffusion theory.

The reference c~nfiguration o

kegg using KENO resulted in a value of 0.9074 and corresponding Ak of +0.0255.

The k gg for the worst case normal configuration with bias is e

0.9168.

The resulting k gg for the worst case abnormal con-k,fg = ion is keff = 0.9313.

e figurat 7.6 Effects of Calculational Uncertaintv The k gg values presented in the previous sections do not include e

the effect of calculational uncertainties.

In order to accurately assess the uncertainty of a specified calculational system, it is necessary to compare many calculational results with the corresponding criticality experiments.

Consequently, NES has investigated the open literature to determine what uncertainty values are assigned to criticality computations after comparisons with many experiments have been made.

The uncertainties, depending upon the specific com-bination of codes used to determine the cross sections and the multiplication constant, range from less than 0.00'l to less than 0.015 at the 95 percent confidence level'.

For the purposes-of assessing the impact of calculstional un-certainty, NES has assumed a value of 0.01.

When this uncertainty is combined st-*i ?*.ically with the kegg values associated with 0.9356 for the " worst case" abnormal configuration.,gg value becomes the normal configu;ations, the upper limit of the k Even if it is assumed that the calculation uncertainty is 0.02, the resulting keff for the " worst case" abnormal configuration is still less than the criticality design criterion value (0.95).

Therefore it can be concluded that the Crystal River Unit 3 high density storage racks when loaded with the specified fuel are safe from a criticality viewpoint.

l I

l 7-:

~

TABLE 7.1 j

COMPONENT DIMENSIONS FOR 15 x 15 BABCOCK & WILCOX FUEL ITEM MATERIAL DIMENSIONS (INCHES)

Ave 528 kg (1)

Mass UO2/Assy UO2 Max 536.94 kg Fuel rod:

(a) Fuel UO2 sintered 0.370 diameter

~_

pellets (92.5%

theoretical density) = when 9.6368 gm/cc f

smeared to clad 1

ID (b) Fuel Clad Zircaloy-4 0.430.OD x 0.377 ID x 153-1/8 long (c) Fuel rod 0.568 pitch (d) Active fuel 144 length 0.366 diameter (e) Ceramic spacer Zr02 (f) Minimum fuel to 0.0045 clad gap (BOL)

(2)

Fuel assembly:

(a) Fuel assembly 8.587 square dimension (b) Overall Length 165-5/8 (c) Control rod Zircaloy-4 0.530 OD x guide tube 0.016 wall (d) Instrumentation Zircaloy-4 0.493 OD x tube 0.441 ID (e). End Fittings Stainless Steel (castings)

(f) Spacer grid Inconel-718 0.020 thick exteriors strips 0.016 thick interiors (g) -Spacer Sleeve Zircaloy-4 0.554 OD x 0.502 ID 7-5

~

TABLE 7.2 FUEL-HAMMER INPUT DATA fuel

Clad atoms /b-cm atoms /b-cm Moderator ** atoms /b-cm Enrichment,

Temp, Pure W'ater 238 okygen Zirconium Hydrogen Oxygen 235 U

w/o

F Density, gm/cc U

3.3 68*

.998 7.183-4 2.078-2 4.3 00-2 4.29-2 6.6348-2 3.3174-2 3.3 39' 1.000 7 183-4 2.078-2 4.300-2 4.29-2 6.6466-2 3 3233-2 33 90*

.995 7 183-4 2.078-2 4.300-2 4.29-2 6.6137-2 3.3068-2 3.3 212*

958 7.183-4 2.078-2 4.300-2 4.29-2 6.3699-2 3.1849-2 3.3 260*

938 7.183-4 2.078-2 4.300-2 4.29-2 6.2345-2 3.1172-2

{

3.3 220'

.907 7 183-4 2.078-2 4.300-2 4.29-2 6.0309-2' 3.0154-2 3.1 68*

.998 6.748-4 2.082-2 4.300-2 4.29-2 6.6348-2 3 3174-2 3.5 68*

.998 7.618-4 2.074-2 4.300-2 4.29-2 6.6348-2 3.3174-2

Fuel.'ellet 0.D. =.377" Clad 0.D.

=.430" Pitch

=.568" note that pell'et and gap are smeared

- In addition, the moderator has:

Nickel 2.418-4, Chrome 9.671-5, iron 8.953-5 atoms /b-cm

TABLE 7.3 FOUR GROUP HAMMER X-SECTIONS FOR FUEL REGIONS Grouc #

D Zr Ea vZf 3.3 w/o, 68' F, 0.998 gm/cc 1

1.94258 7.87730-2 4.28100-3 8.61700-3 2

1.00866-7.96070-2 2.60000-3 1.03200-3 3

7.15394-1 7.01250-2 2.43180-2 1.42200-2 4

2.73752-1 0.

1.11507-1 1.86895-1 3.3 w/o, 212' F,

.958 gm/cc 1

1.98237-7.65070-2 4.26300-3 8.59000-3 2

1.02964 7.64640-2 2.59900-3 1.03100-3 3

7.35263-1 6.69780-2 2.42360-2 1.42010-2 4

2.91370-1 0.

1.02900-1 1.72738-1 3.3 w/o,.260* F,

.955 gm/cc 1

2.00338 7.53466.2 4.25400-3 8.57500-3 2

1.04073 7.48570-2 2.59800-3 1.03100-3 3

7.45856-1 6.53710-2 2.41920-2 1.41910-2 4

2.98596-1 0.

1.00907-1 1.69583-1 3.3 w/o, 220' F, 5% voids,.907 gm/cc 1

2.03584 7.36000-2 4.24000-3 8.55300-3 2

1.05787 7.24410-2 2.59800-3 1.03100-3 3

7~.62364-1 6.29570-2 2.41240-2 1.41760-2 4

3.05980-1 0.

1.01507-1 1.71026-1 3.1 w/o, 68* F, 0.998 gm/cc

'1 1.94272 7.87770-2 4.26900-3 8.58400-3 2

1.00869 7.96170-2 2.57200-3 9.70000-4 3

7.15402-1 7.03420-2 2.38500-2 1.34170-2 4

2.73485-1 0.

1.07690-1 1.7850-1 3.5 w/o, 68* F,.0.998 gm/cc 1

1.94244 7.87690-2 4.29400-3 8.65000-3 2

-1.00864 7.95970-2 2.62700-3 1.09400-3 3

7.15384-1 6.99110-2 2.47820-2 1.501 0-2 4

2.73969-1 0.'

l.15226-1 1.95047-1 e

6 7-7

l TABLE 7.3 (con ' t)

Group #'

D Ir Ia Ivf 3.3 w/o, 39' F, 1-000 gm/cc 1

1.94086 7.88730-2 4.28200-3 8.61800-3 2

1.00776

-7.97460-2 2.60000-3 1.03200-3

~

3 7.14539-1 7.02650-2 2.43210-2 1.42200-2 4

2.73304-1 0.

1.11560-1 1.86958-1 3.3 w/o, 90* F, 0.995 gm/cc 1

1.94570 7.85920-2 4.28000-3 8.61500-3 2

' l.01031 7.93560-2 2.60000-3 1.03200-3 3

7.16943-1 6.98730-2 2.43120-2 1.42180-2 4

2.75562-1 0.

1.10279-1 l.84850-1 9

e 7-8

j iABLE 7.4

' CRYSTAL RIVER BASE CASE REFERENCE CASE EXTERMINATOR INPUT OPTION CARD I I I I I I 0 -0 2.1 0 0 0 0 0 0 0 0 -0 0 0 0 -0 I -0 SPECIFICATIONS-19 ROWS.

19 COLS 4 9RPS 6 COMPS

-0 NUCS L, T,R,8 BHD I I I I FPI 5.0000E-04 NORM FAC.

1.000000E+00.

THIS CASE HAS X-Y GEONETRY, AND IS AN ElGENVALUE CALC.

FISSION-SOURCE CHl(K) 7532

.2466

.0002 0.0000 i

MESH SPECIFICATIONS I

DELTA i

1.443 7

399 8

1.044 9

1.443 to

.148 11 533 12'

.095 14 533 15 317 19 J

DELTA i

1.443 7

399 8

1.044 9

1.443 10

.148 11 533 12

.095 14 533 15 317 19 DlHENSION SPECIFICATIONS I

I DIST l

2 721 3

2.164 4

3.606 5

5.049 6

6.491 7

7 934 8

8.333 9

9.376 10 10.819

^

11 10 968

12. 11 502 13 11.597 14 11.692 15 12.225 16 12.542 17 12.859 18 13.175 19 13.492 3

a 1 DIST 2

721 3

2.164 4

3.606 5

5.049 6

6.491 7

7 934 8

8.333 9

9.376 10 10.819 11 10 968 12 11 502 13 11.597 14 11.692 15 12.225 16 12.542 17 12.859 18 13.175 19 13.492

i TABLE 7.4. (continu::d)

CRYSTAL RIVER BASE CASE REACTOR MATERIAL PICTURE I

2 3

4 5

'6 7

8 9

10 11 12 13 14' 15 16 17.

18 19 I

.2 1

1 I

l' I

i 1

l' 3

4

'S 5

4 3

3 3

3 2

I l'

1 1

1 I

.I I

I 3

4 5

5 4

3 3

3-3 3

1-1 2

1 1

2 1

1 1

3 4

5 5

4 3

3 3

3-4 1

1 1

I I

3 4

5 5

4 3

'3 3-3 5

1 1

I I

2 1

1 1

1 3

4 5

5 4

3 3

6 1

1 2

I I

3 4

5 5

4 3

3' 3

3 7

1 1

1 3

4 5

5 4

3 3

3 3-8 I

I I

I i

1 1

3 4

6 6

6 3

3 3

3 w

9 O-1 I

.I I

1 1

I I

I 3

4 6

6 6

3 3

0 10 3

3 3

3 4

6 6

6 3

3 3

3 11 4

4 4

6 6

3 3

3 12 5

5 5

6 6

3 3

3 13 5

5 5

5 6

6 6

6 3

3 3

14 4

4 4

6 6

6 3

3 3

3 15 3

3 3

3 16 3

3 3

3 17 3

3 3

3 18 3

3 3

3 3'

3 3

3 LEGEND Fuel 2 - Guide Tubes

'3 - Water 4 - gr less Steel 5 5 - Poison 6 - Stainless Steel

a N

~

N N

m O

O O

O e

a e

e e

e W

W W

W O'

m O

O O

O 4

m m

m to O

N 2

2 O

~

r3 m

o c0 m

. O.

. m.

2

. ~.

. m.

. M.

OONO OO~O OO~O OO@O OONO OO~O a

e e

I e

~

N N

m N

O O

e e

I e

8 i

W W

O O

O m

t%

CO t%

2 a

O O

N

.=

m m

~

m a

co N

N n

~

. m.

4

. Cn.

. m.

. M.

ONOO OOOO O~CO O CO O O O 'O C O C400 s

e e

e a

e Tv N

N

=

N N

N

3 O

O O

O c

s e

e e

e t

}

W W

==

O O

N m' w

Cn m

m m

N C

O N

O 4

m M

CR u

N CO f%

CD CD m

w C0 m.

O.

CO.

4 COO NOOO t% Q O 3 MOOO 4

NOOO (noOO

~

e 8

8 I

I 4

r%

W J

CD<

W

~OOOO OOOO OCOO OCOO OOOO COOO I

a.

M c

OW i

m K~NM4

=Nm4

=Nm2

=NMM

~Nm2

~Nmg

=

M c

E

~

W W

H CL

-E u

o~

N m

c ~.

m m

W O

_11

6

+

W O~CCOO OOOO COOO OOOO COOO COCO m

mmmm mmmm mmmm mmmm mmmm mmmm OOOO COOO 0000 0000 0000 0000 e a e a e a e a a e a a a e a e a a a e a e e s WWWW WWWW WWWW WWWW WWWW WWWW OOOO COOO OOOO OOOO OOOO OOOO COOO OOOO OOOO COOO OOOO OOOO N 0000 0000 0000 0000 0000 0000 Emmmm mmmm mmmm mmmm mmmm mmmm N. N. N. N.

N. N. N. N.

N.N N. N.

N. N. N. N.

N N.N. N.

W u

g 3O000 0000 0000 0000 000C COCO O e a e s e e e a e s : s e a : a a e e e a e e s

/

m' e

MMN-COOO e e e a WWWW NCoom n

t COOm A NNND U3

-mNQ

@ C. c. w.

c

~

u C===

OOOO C000 COCO OCCC C000 C

O u

w mmN~

ammN cMmN cmmN dN=O ccm~

a.

0000 0000 0000 0000 0000 0000 N

s e e

e e a s e a e e a e a e s e e +

e e e s WWWW WWWW WWWW WWWW WWWW WWWW W

COON Coom OOOO C000 0000 0000 a

acomo C00@

000@

0004 OONm Coom m

-O-m Com@

OOQm O-cN 0-NN OOmm 4

Come modm mO~@

MkmN DNmm MM@@

N. @. M. ~.

N. O. N. N.

m m. O. N.

m. 4. N. m.

4. %. C. =.

O. m. D. N.

4 N N.=

mm==

Mm==

mm mm m=@@

Nmm=

NNN N~~

~~~

NNN NNN Nmm C00 000 000 000 000 000 s e e e e e a e e a e e a e e e e a WWW WWW WWW WWW WWW WWW b

OOO O@ m C00 000 000 000 WmNm mm@

MNm MJM MMM NOC NON ONC M-4 mme WMC m==

N4~

-cMmn NMm MNO

@ND mcm W m. C.

m. m. m.

044

%. m. m D. m. m.

A. m. m.

Y N

CO-~

CO--

00--

OO-N 00==

w OOOO OOOO OOOO OOOO OOOO OOOO 2

++ 4 :

+ + e a

++ 4 e

+ +e s

++ e s

++ e a O

WWWW WWWW WWWW WWWW WWWW WWWW M

N ONN-0000 mNmo mWOO C000 O m @ @m m c

mm-M m@ m@

@mNm

@mO-

@mNm H

N@mN Nm2~

NmON N@MM N@NM m@mm u

Momm

@N@ c

@@mW M-m-M-#N mcmm MO-N Coom

-OQ'*

=NOR

NQN

@ O m. N 6

~~hN N~@=

m^-m~

N_~ m N

_N_= 4__N. _ _ _ _. _ _ ~ _ mm

~

W.

A M

A Z M=Nm2

=NR4

~Nm2

=NM4

~NR4

=Nm2 O O OA A Z Z O

O=

N m

a m

W W

l l

l 7-12

TABLE 7.5 PAF.AMETERS AND RESULTS OF EXTERMlHATOR CALCULATIONS IO H O DENSITY BOX WALL 80X 00,-

AVERAGE B

DENSITY, 2

FUEL ENRICHMENT,W/0 P ITCH, IN, ATOMS /B-CH TEMP,0F gm/cc THICKNESS,1N INCHES AKEFF Keff =

Reference Case 3.3 10.5 0.00379 68 0.998

.195 9.328 0.8819 Maximum Water Density 3.3 10.5 0.00379 39 1.000

.195 9 328

+0.0115 900F 3.3 10 5 0.00379 90 0 995

.195 9 328

-0.00:

212"F 33 10.5 0.00379 212 0.958

.195 9 328

-0.0156' 260of 3.3 10.5 0.00379 260 0 955

.195 9 328

-0.0209 220"F 5% voids 33 10.5 0.00379 220 0 90

.195 9 328

-0.0276, High Enrichment 3.5 10.5 0.00379 68 0.998

.195 9 328

+0.0121 Low Enrichment 31 10.5 0.00379 68 0 998

.195 9.328

-0.0133 High B10 Concentration 33 10.5 0.00417 68 0.998

.195 9 328

-0.0010' Low Bl0 Concentration 3.3 10.5 0.00341 68 0.958

.195 9.328

+0.0014

~

y 8

Thick Wall 33 10.5 0.00379 68 0.998

.215 9.348

-0.0008 U

Thin Wall 33 10.5 0.00379 68 0 998

.175 9.308

+0.0009 Dropped Fuel 6" From Rack 33 10.5 0.00379 68 0.998

.195 9 328

+0.0032 Eccentric Fuel 3.3 10.5 0.00379 68 0 998

.195 9 328

.0029 Eccentric Can 33 10.5 0.00379 68 0.998

.195 9 328

+0.0055-Pitch Variation +.25" 3.3 10.75 0.00379 68 0.998

.195 9 328

.0264 Pi tch Variation

.25" 33 10.25 0.00379 68 0 998

.195 9 328

+.030V i

a I

\\

4 Fuel O.D. = 0.377"~

d Zirconium Clad O.D. = 0.430" I.D. = 0.377" j

/-

Water Moderator Region O.D. = 0.568" Outer Water Region Square O.D. = 0.568" s

.N

?

^

Guide Tube Interior

/

Water Region O.D. = 0.498" W

/

Zirconium Guide Tube O.D. = 0.530" I.D. = 0.498" i

ILLUSTRATION OF HAMMER MODELS USED TO DETERMINE FUEL AND GUIDE TUBE CROSS SECTIONS FOR 15 x 15, 3.3 w/o BABCOCK & WILCOX FUEL FIGURE 7.1 auctsan ettasy sr= vers ac 7-14

1 i

l Reflected B C Poison Wall

.812 gm/cm2 1

B0 Boundary 304 Stainless Steel HO 2

l 1

1

/

' l..

i i

Off) cl l l

L$

!.l 1

l I

0.375" l

l.060" l

l:

I y

I l.150" e

r POISON WALL MODEL USED IN PJuMMER CALCULATIONS TO DETERMINE HOMEGENEOUS X-SECTIONS FIGURE 7.2 l

=vettaa tstacv stavers e.e.

7-15

AK VS. FUEL ENRICEIENT FOR EFF CRYSTAL RIVER UNIT 3 SFENT FUEL STORAGE RACK 0.02 O.01 0.00

^ EFF

-0.01

-0.02 l

6 I

I I

I i

i l

i 3.1-3.3 3.5 EITRICBMT,w/o FIG. 7.3 e

AK VS. TEMPERATURE FOR gyp CRYSTAL RIVER UNIT.3 SPENT FUEL STORAGE RACK 0,01 o

0.00 Ab?F 0.01

-0.02 N

-0.03 l

6 l

1 1

I l1 I

I i

50 100 150 200 250 TE'GERa.TU9E 07 FIG. 7.4 a

e

AK VS. WATER DENSITY FOR ggy CRYSTAL RITER UNIT 3 SPEUT FUEL STORAGE RACF.

0.01 0.00

~

A AK EFF

-0.01

-0.02

-0.03 I

I I

I i

6 I

l l

0.900 0.950 1.000 WATER DEUSITY,gm/cc FIG. 7.5 e

h jg_...,;..........

7-18

AZ VS. PITCH V ARIATION FOR

+

g77 CRYSTAL. RIVER UNIT 3 SPENT FUEL STORAGE RACK 1

0.04 a

0.02 ObFF 0.00

-0.02

-0.04 l

I i

i i

I i

n

-0.25 0.00

+0.25 PITCH VARIATION, INCHES

' FIG. 7.6 e

i ~

l

NuCLEam ENtpCT SEmytCES.fMC.

7-19 i

?

10 AK VS. 3 CONCENTRATION FOR gyp CRYSTAL RIVER UNIT'3 SPENT FUEL STORAGE RACK 0.002 w

0.001

EEFF 0.000

-0.001 l

I I

i i

l I

i I

(

-10%

0

+10%

FEPCENT VARIATION ON BASE CASE B CONCENTRATION OF 0.00379 ATOMS /3ARIT-CM FIG. 7.7 e

I

AKEFF.VS. STAINLESS STEEL WALL THICKNESS FOR CRYSTAL RIVER UNIT 3 S?ENT FUEL STO, RAGE RACK M

0.0008 O.0004 A K 'FF E

0.0000

-0.0004

~

-0.0008 l

i I

I I

i

-0.020 0

+0.020 VARIATION OF STAINLESS STEEL THICKNESS IN POISON WALL,'INOHES FIG 7.8

- m.,

A 7-21

8.

REFERENCES 1.

USNRC Standard Review Plan, Spent Fuel Storage, Section 9.1.2 (February, 1975).

2.

NES.BlA0260 " Criticality Analysis of the Atcor Vandenburgh Cask" R.J. Waader, February, 1975.

3.

DP-1064, the HAMMER System, J.E.

Sutch and H.C. Honeck, January, 1967.

4.

ORNL-4078, EXTERMINATOR-2, T.B.

Fowler et al, April, 1967.

~~

5.

L.M.

Petrie, N,F.

Cross, " KENO IV - An Improved Monte Carlo Criticality Program", ORNL-4938, November, 1975.

s e

n weh,~,,-

en

-e_

9 e

-4 8-1

.

ML19319D199

Text

SUMMARY

SUMMARY

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