CSAS6: Control Module for Enhanced Criticality Safety Analysis with KENO-VI

L. M. Petrie, K. B. Bekar, D. F. Hollenbach,1 S. Goluoglu1

The Criticality Safety Analysis Sequence with KENO-VI (CSAS6) provides reliable and efficient means of performing keff calculations for systems that are routinely encountered in engineering practice. In the multigroup calculation mode, CSAS6 uses XSProc to process the cross sections for temperature corrections and problem-dependent resonance self-shielding and calculates the keff of three-dimensional (3-D) system models. If the continuous energy calculation mode is selected no resonance processing is needed and the continuous energy cross sections are used directly in KENO-VI, with temperature corrections provided as the cross sections are loaded. The geometric modeling capabilities available in KENO-VI coupled with the automated cross-section processing within the control sequences allow complex, 3-D systems to be easily analyzed.

1Formerly with Oak Ridge National Laboratory

ACKNOWLEDGMENTS

The CSAS6 Criticality Safety Analysis Sequence is based on the CSAS control module, and the KENO‑VI functional module, described in their respective chapters. G. E. Whitesides is acknowledged for his contributions through early versions of KENO. Appreciation is expressed to C. V. Parks and S. M. Bowman for their guidance in developing CSAS6.

Introduction

Criticality Safety Analysis Sequence with KENO-VI (CSAS6) provides reliable and efficient means of performing keff calculations for systems that are routinely encountered in engineering practice, especially in the calculation of keff of three-dimensional (3-D) system models. CSAS6 implements XSProc to process material input and provide a temperature and resonance-corrected cross-section library based on the physical characteristics of the problem being analyzed. If a continuous energy cross-section library is specified, no resonance processing is needed and the continuous energy cross sections are used directly in KENO-VI, with temperature corrections provided as the cross sections are loaded.

Sequence Capabilities

CSAS6 is designed to prepare a resonance-corrected cross-section library for subsequent use in KENO‑VI. In order to minimize human error, the SCALE data handling is automated as much as possible. CSAS6 and many other SCALE sequences apply a standardized procedure to provide appropriate number densities and cross sections for the calculation. XSProc is responsible for reading the standard composition data and other engineering-type specifications, including volume fraction or percent theoretical density, temperature, and isotopic distribution as well as the unit cell data. XSProc then generates number densities and related information, prepares geometry data for resonance self-shielding and flux-weighting cell calculations, if needed, and (if needed) provides problem-dependent multigroup cross-section processing. CSAS6 invokes a KENO-VI Data Processor to read and check the KENO-VI data. When the data checking has been completed, the control sequence executes XSProc to prepare a resonance-corrected microscopic cross-section library in the AMPX working library format if a multigroup library has been selected.

For each unit cell specified as being cell-weighted, XSProc performs the necessary calculations and produces a cell-weighted microscopic cross-section library. KENO-VI may be executed to calculate the keff or neutron multiplication factor using the cross-section library that was prepared by the control sequence.

Multigroup CSAS6 limitations

The CSAS6 control module was developed to use simple input data and prepare problem-dependent cross sections for use in calculating the effective neutron multiplication factor of a 3-D system using KENO-VI and possibly XSDRNPM. An attempt was made to make the system as general as possible within the constraints of the standardized methods chosen to be used in SCALE. Standardized methods of data input were adopted to allow easy data entry and for quality assurance purposes. Some of the limitations of the CSAS6 sequence are a result of using preprocessed multigroup cross sections. Inherent limitations in CSAS6 are as follows:

1. Two-dimensional (2-D) effects such as fuel rods in assemblies where some positions are filled with control rod guide tubes, burnable poison rods and/or fuel rods of different enrichments. The cross sections are processed as if the rods are in an infinite lattice of rods. If the user inputs a Dancoff factor for the cell (such as one computed by MCDancoff), XSProc can produce an infinite lattice cell, which reproduces that Dancoff. This can mitigate some two dimensional lattice effects.

It is strongly recommended that the user perform CSAS6 calculations of benchmark experiments similar to the problem of interest to demonstrate the validity of the cross-section data and processing for that type of problem.

Continuous energy CSAS6 limitations

When continuous energy KENO calculations are desired, none of the resonance processing modules are applicable or needed. Moreover, the MG limitations noted in the previous section are eliminated. The continuous energy cross sections are directly used in KENO. An existing multigroup input file can easily be converted to a continuous energy input file by simply specifying the continuous energy library. In this case, all cell data is ignored. However, the following limitations exist:

  1. If CELLMIX is defined in the cell data, the problem will not run in the continuous energy mode. CELLMIX implies new mixture cross sections are generated using XSDRNPM-calculated cell fluxes and therefore is not applicable in the continuous energy mode.

  2. Only VACUUM, MIRROR, PERIODIC, and WHITE boundary conditions are allowed. Other albedos, e.g., WATER, CARBON, POLY, etc. are for multigroup only.

  3. Problems with DOUBLEHET cell data are not allowed as they inherently utilize CELLMIX feature.

Input Data Guide

The input data for CSAS6 are composed of two broad categories of data. The first is XSProc, including Standard Composition Specification Data and Unit Cell Geometry Specification. This first category specifies the cross-section library and defines the composition of each mixture and optionally the unit cell geometry that may be used to process the cross sections. The second category of data, the KENO-VI input data, is used to specify the geometric and boundary conditions that represent the physical 3-D configuration of the problem. Both data blocks are necessary for CSAS6.

All data are entered in free form, allowing alphanumeric data, floating-point data, and integer data to be entered in an unstructured manner. Up to 252 columns of data entry per line are allowed. Data can usually start or end in any column with a few exceptions. As an example, the word END beginning in column 1 and followed by two blank spaces or a new line will end the problem and any data following will be ignored. Each data entry must be followed by one or more blanks to terminate the data entry. For numeric data, either a comma or a blank can be used to terminate each data entry. Integers may be entered for floating values. For example, 10 will be interpreted as 10.0. Imbedded blanks are not allowed within a data entry unless an E precedes a single blank as in an unsigned exponent in a floating-point number. For example, 1.0E 4 would be correctly interpreted as 1.0 × 104.

The word “END” is a special data item. An “END” may have a name or label associated with it. The name or label associated with an “END” is separated from the “END” by a single blank and is a maximum of 12 characters long. At least two blanks or a new line MUST follow every labeled and unlabeled “END.” It is the user’s responsibility to ensure compliance with this restriction. Failure to observe this restriction can result in the use of incorrect or incomplete data without the benefit of warning or error messages.

Multiple entries of the same data value can be achieved by specifying the number of times the data value is to be entered, followed by either R, *, or $, followed by the data value to be repeated. Imbedded blanks are not allowed between the number of repeats and the repeat flag. For example, 5R12, 5*12, 5$12, or 5R 12, etc., will enter five successive 12s in the input data. Multiple zeros can be specified as nZ where n is the number of zeroes to be entered.

The purpose of this section is to define the input data in discrete subsections relating to a particular type of data. Tables of the input data are included in each subsection, and the entries are described in more detail in the appropriate sections.

Resonance-corrected cross sections are generated using the appropriate boundary conditions for the unit cell description (i.e., void for the outer surface of a single unit, white for the outer surface of an infinite array of cylinders, spheres, or planes). As many unit cells as needed may be specified in a problem. A unit cell is cell‑weighted by using the keyword CELLMIX= followed by a unique user specified mixture number in the unit cell data.

To check the input data without actually processing the cross sections, the words “PARM=CHECK” or “PARM=CHK” should be entered, as shown below.

=CSAS6 PARM=CHK

or

#CSAS6 PARM=CHK

This will cause the input data for CSAS6 to be checked and appropriate error messages to be printed. If plots are specified in the data, they will be printed. This feature allows the user to debug and verify the input data while using a minimum amount of computer time.

XSProc data

The XSProc reads the standard composition specification data and the unit cell geometry specifications. It then produces the mixing table and unit cell information necessary for processing the cross sections if needed. The XSProc section of this manual provides a detailed description of the input data and processing options.

KENO-VI data

Table 62 contains the outline for the KENO-VI input. The KENO-VI input is divided into 13 data blocks. A brief outline of commonly used data blocks is shown in Table 62. Note that parameter data must precede all other KENO data blocks. Information on all KENO-VI input is provided in the KENO chapter of this document and will not be repeated here.

Table 62 Outline of KENO data

Type of data

Starting flag

Comments

Termination flag

Parameters*

READ PARAMETER

Enter desired parameter data

END PARAMETER

Geometry

READ GEOMETRY

Enter desired geometry data

END GEOMETRY

Array data

READ ARRAY

Enter desired array data

END ARRAY

Boundary conditions

READ BOUNDS

Enter desired boundary conditions

END BOUNDS

Energy group boundaries

READ ENERGY

Enter desired neutron energy group boundaries

END ENERGY

Start data or initial source

READ START

Enter desired start data

END START

Plot data

READ PLOT

Enter desired plot data

END PLOT

Grid geometry data

READ GRID

Enter desired mesh data

END GRID

Reaction

READ REACTION

Enter desire reaction tallies (CE mode only)

END REACTION

KENO-VI data terminus

END DATA

Enter to signal the end of all
KENO-VI data

*Must precede all other data blocks in this table.

Sample Problems

This section contains sample problems to demonstrate some of the options available in CSAS6. A brief problem description and the associated input data for multigroup mode of calculation are included for each problem. The same sample problems may be executed in the continuous energy mode by changing the library name to an continuous-energy library. See Appendix A (SECTIONREFERENCE) for additional examples.

Sample Problem 1: Aluminum 30 Degree Pipe Angle Intersection

The purpose of this problem is to calculate the k-effective of a system composed of intersecting aluminum pipes, in the shape of a Y, filled with a 5% enriched UO2F2 solution. The UO2F2 solution at 299°K contains 907.0 gm/l of uranium, no excess acid, and has a specific gravity of 2.0289 gm/cm3. The assembly is composed of a 212.1 cm long vertical pipe and a second pipe that intersects the vertical pipe 76.7 cm from the outside bottom at an angle of 29.26 degrees with the upper vertical pipe. Both pipes have 13.95 cm inner diameters and 14.11 cm outer diameters. The vertical pipe is open on the top and 1.3 cm thick on the bottom. The Y-leg pipe, in the YZ-plane, is 126.04 cm in length with the sealed end 0.64 cm thick. The assembly is filled with solution to a height 129.5 cm above the outside bottom of the vertical pipe. From the point where the pipes intersect the assembly is surrounded by water 37.0 cm in the ±X directions, 100 cm in the +Y direction, –37 cm in the –Y direction, to the top of the assembly in the +Z direction, and –99.6 cm in the –Z direction.

_images/fig11.png

Fig. 91 Critical assembly of UO2F2 solution in a 30°-Y aluminum pipe.

=csas6
sample problem 1  Y-30, 5%uo2f2, 907.0g/l, 128.2, soln. ht.
v7-238
read comp
  solution
    mix=1
    rho[uo2f2]=907.0 92235 5.0 92238 95.0
    density=?
    temperature=299.0
  end solution
  al        2 1.0 end
  h2o       3 1.0 end
end comp
read parameters
  flx=yes fdn=yes far=yes pgm=yes plt=yes
end parameters
read start
  nst=6 tfx=0.0 tfy=0.0 tfz=0.0 lnu=1000
end start
read geometry
  global
  unit 1
    com='30 deg y'
    cylinder 10  13.95  135.4 -75.4
    cylinder 20  14.11  135.4 -76.7
    cylinder 30  13.95  125.4   0.0   rotate a2=-29.26
    cylinder 40  14.11  126.04  0.0   rotate a2=-29.26
    cuboid   50  2p37.0 100. -37.0 52.8 -75.4
    cuboid   60  2p37.0 100. -37.0 135.4 -99.6
    media  1  1 10  50
    media  2  1 20 -10 -30
    media  1  1 30  50 -10
    media  2  1 40 -30 -20
    media  0  1 10 -50
    media  0  1 30 -50 -10
    media  3  1 60 -20 -40 -10
    boundary  60
end geometry
read volume
    type=random  batches=1000
end volume
read plot
  scr=yes  lpi=10
  ttl='y-z slice at x=0.0  through centerline of both pipes'
  xul=0.0  yul=-39.0  zul=137.0
  xlr=0.0  ylr=105.0  zlr=-105.0
  vax=1    wdn=-1
  nax=400  end plt0
  ttl='x-y slice at z=26.0  slightly above point of separation'
  xul=-40.0 yul=105.0  zul=26.0
  xlr=+40.0 ylr=-40.0  zlr=26.0
  uax=1     vdn=-1
  nax=400 end plt1
  ttl='x-y slice at z=75.0  well above point of separation'
  xul=-40.0 yul=105.0  zul=75.0
  xlr=+40.0 ylr=-40.0  zlr=75.0
  uax=1     vdn=-1
  nax=400 end plt2
end plot
end data
end

Sample Problem 2: Plexiglas Cross

The purpose of this problem is to calculate the k-effective of a system composed of intersecting Plexiglas pipes, in the shape of a cross, filled with a 5% enriched UO2F2 solution. The room temperature UO2F2 solution contains 896.1 gm/l of uranium, no excess acid, and has a specific gravity of 2.015 gm/cm3. The pipes have a 13.335 cm inner diameter and 16.19 cm outer diameter. The vertical pipe is open on the top and 3.17 cm thick on the bottom. The horizontal pipe ends are 3.17 thick. The vertical pipe is 210.19 cm in length and filled with solution to a height of 117.2 cm. The two horizontal legs, positioned in the XZ‑plane, intersect the vertical pipe 91.44 cm from the outside bottom at an 89 degree angle with the upper section of the pipe. Each horizontal is 91.44 cm in length and filled with the above specified UO2F2 solution. A water reflector surrounding the solution filled pipes extends out from the point where the pipes intersect 111.76 cm in the ±X directions, 20.64 cm in the ±Y directions, 29.03 cm in the +Z direction, and –118.428 cm in the –Z direction.

_images/fig2.png

Fig. 92 Critical assembly of UO2F2 solution in a Plexiglas cross.

=csas6
sample problem 2  89-cross, 5% uo2f2 soln, plexiglass pipes, h2o refl.
v7-238
read comp
  solution
    mix=1
    rho[uo2f2]=896.1 92235 5.0 92238 95.0
    density=?
    temperature=298.0
  end solution
  plexiglass 3 1.0 end
  h2o        2 1.0 end
end comp
read param
  plt=yes
end param
read geom
  global unit 1
    cylinder  10  13.335 28.93 -88.27
    cylinder  20  13.335 121.92 -88.27
    cylinder  30  16.19 121.92 -91.44
    cylinder  40  13.335 88.27 0.0 rotate a1=90. a2=89.
    cylinder  50  16.19  91.44 0.0 rotate a1=90. a2=89.
    cylinder  60  13.335 88.27 0.0 rotate a1=-90. a2=89.
    cylinder  70  16.19  91.44 0.0 rotate a1=-90. a2=89.
    cuboid    80  2p111.74 2p20.64 29.03 -118.428
    cuboid    90  2p111.74 2p40.64 121.92 -118.428
    media 1 1 10
    media 0 1 20 -10
    media 3 1 30 -10 -20 -50 -70
    media 1 1 40 -10 -20
    media 3 1 50 -40 -10 -20
    media 1 1 60 -10 -20
    media 3 1 70 -60 -10 -20 -50
    media 2 1 80 -10 -20 -30 -40 -50 -60 -70
    media 0 1 90 -20 -30 -80
    boundary  90
end geom
read volume
   type=trace
end volume
read start
  nst=6  tfx=0. tfy=0. tfz=0. lnu=1000
end start
read plot
  scr=yes  lpi=10
  ttl=' x-z slice at y=0.0 '
  xul=-113. yul=0. zul=  48.
  xlr= 113. ylr=0. zlr=-120.
  uax=1.0   wdn=-1.0
  nax=400  end plt0
  ttl=' y-z slce at x=0.0 '
  xul=0.    yul=-42. zul= 122.
  xlr=0.    ylr= 42. zlr=-120.
  vax=1.0   wdn=-1.0
  nax=400  end plt1
  ttl=' x-y slice at z=0.0 '
  xul=-113.0 yul= 42. zul=0.
  xlr= 113.0 ylr=-42. zlr=0.
  uax=1.0    vdn=-1.0
  nax=400  end plt2
end plot
end data
end

Sample Problem 3: Sphere

This problem models an assembly consisting of a 93.2% enriched bare uranium sphere, 8.741 cm in radius, having a density of 18.76 gm/cm3. Problem 3 models the assembly as a single bare sphere. The second problem models the assembly as a hemisphere with mirror reflection on the flat surface. The next three problems model the sphere using chords. This set of four problems is designed to illustrate the use of multiple chords in a problem.

=csas6
sample problem 3  bare 93.2% enriched uranium sphere
v7-238
read comp
  uranium  1 den=18.76 1 293 92235 93.2 92238 5.6 92234 1.0 92236 0.2 end
end comp
read geometry
  global unit 1
    sphere 10  8.741
    cuboid   20  6p8.741
    media  1 1 10      vol=2797.5121
    media  0 1 20 -10  vol=2545.3424
    boundary 20
end geometry
end data
end

Sample Problem 4: Sphere Models Using Chords and Mirror Albedos

This problem models an assembly consisting of a 93.2% enriched bare uranium sphere, 8.741 cm in radius, having a density of 18.76 gm/cm3. The problem models the assembly as a hemisphere with mirror reflection on the flat surface.

=csas6
sample problem 4  bare 93.2% U sphere, hemisphere w/ mirror albedo
v7-238
read comp
  uranium  1 den=18.76 1 293 92235 93.2 92238 5.6 92234 1.0 92236 0.2 end
end comp
read geometry
  global unit 1
    sphere 10  8.741  chord +x=0.0
    cuboid   20  8.741 0.0  8.741 -8.741 8.741 -8.741
    media  1 1 10      vol=2797.5121
    media  0 1 20 -10  vol=2545.3424
    boundary 20
end geometry
read bounds
  -xb=mirror
end bounds
end data
end

Sample Problem 5: Sphere Models Using Chords and Mirror Albedos

This problem models an assembly consisting of a 93.2% enriched bare uranium sphere, 8.741 cm in radius, having a density of 18.76 gm/cm3. The problem models the assembly as a quarter sphere with mirror reflection on the two flat surfaces.

=csas6
sample problem 5  bare 93.2% U sphere, quarter sphere w/ mirror albedo
v7-238
read comp
  uranium  1 den=18.76 1 293 92235 93.2 92238 5.6 92234 1.0 92236 0.2 end
end comp
read geometry
  global unit 1
    sphere 10  8.741  chord +x=0.0  chord  +y=0.0
    cuboid   20  8.741 0.0 8.741 0.0 8.741 -8.741
    media  1 1 10      vol=2797.5121
    media  0 1 20 -10  vol=2545.3424
    boundary 20
end geometry
read bounds
  -xy=mirror
end bounds
end data
end

Sample Problem 6: Sphere Models Using Chords and Mirror Albedos (Eighth Sphere)

This problem models an assembly consisting of a 93.2% enriched bare uranium sphere, 8.741 cm in radius, having a density of 18.76 gm/cm3. The problem models the assembly as an eighth sphere with mirror reflection on the three flat surfaces.

=csas6
sample problem 6  bare 93.2% U sphere, eighth sphere w/ mirror albedo
v7-238
read comp
  uranium  1 den=18.76 1 293 92235 93.2 92238 5.6 92234 1.0 92236 0.2 end
end comp
read geometry
  global unit 1
    sphere 10  8.741  chord +x=0.0  chord  +y=0.0  chord +z=0.0
    cuboid   20  8.741 0.0 8.741 0.0 8.741 0.0
    media  1 1 10      vol=2797.5121
    media  0 1 20 -10  vol=2545.3424
    boundary 20
end geometry
read bounds
  -fc=mirror
end bounds
end data
end

Sample Problem 7: Grotesque without the Diaphragm

The purpose of this problem is to calculate the keff of a system composed of eight enriched uranium units placed on a diaphragm, with an irregularly shaped centerpiece positioned in the center hole of the diaphragm [Mih99] The assembly and centerpiece are shown in Fig. 93, which is Fig. 4 from Ref. 1. The eight units consist of an approximate parallelepiped with an irregular top, a parallelepiped, and six cylinders of various sizes. The centerpiece, which penetrates the hole in the diaphragm, consists of a cylinder topped by a parallelepiped topped by a hemisphere. The diaphragm is not modeled in this example.

_images/fig3.png

Fig. 93 Grotesque experimental setup.

=csas6
sample problem 7  keno-vi grotesque w/o diaphragm, ornl/csd/tm-220
v7-238
read comp
  uranium   1 den=18.76 1 293 92235 93.2 92238 5.6 92234 1.0 92236 0.2 end
  uranium   2 den=18.76 1 293 92235 93.2 92238 5.6 92234 1.0 92236 0.2 end
  uranium   3 den=18.76 1 293 92235 93.2 92238 5.6 92234 1.0 92236 0.2 end
  uranium   4 den=18.76 1 293 92235 93.2 92238 5.6 92234 1.0 92236 0.2 end
  uranium   5 den=18.76 1 293 92235 93.2 92238 5.6 92234 1.0 92236 0.2 end
  uranium   6 den=18.76 1 293 92235 93.2 92238 5.6 92234 1.0 92236 0.2 end
  uranium   7 den=18.76 1 293 92235 93.2 92238 5.6 92234 1.0 92236 0.2 end
  uranium   8 den=18.76 1 293 92235 93.2 92238 5.6 92234 1.0 92236 0.2 end
  uranium   9 den=18.76 1 293 92235 93.2 92238 5.6 92234 1.0 92236 0.2 end
  uranium  10 den=18.76 1 293 92235 93.2 92238 5.6 92234 1.0 92236 0.2 end
  uranium  11 den=18.76 1 293 92235 93.2 92238 5.6 92234 1.0 92236 0.2 end
  uranium  12 den=18.76 1 293 92235 93.2 92238 5.6 92234 1.0 92236 0.2 end
  uranium  13 den=18.76 1 293 92235 93.2 92238 5.6 92234 1.0 92236 0.2 end
  uranium  14 den=18.76 1 293 92235 93.2 92238 5.6 92234 1.0 92236 0.2 end
end comp
read param
  pgm=yes plt=yes
end param
read geom
  global unit 1
'*** one through three is item 1 in drawing 84-10649 ornl/csd/tm-220 ***
'one    top piece of item 1
  cuboid 10  2p6.3515 1.2685 -3.8115 13.377 13.058 origin y=-17.464 z=0.15 rotate a2=-1.35
'two    middle piece of item 1
  cuboid 20  2p6.3515 6.3515 -3.8115 13.058 11.155 origin y=-17.464 z=0.15 rotate a2=-1.35
'three  bottom piece of item 1
  cuboid 30  4p6.3515 11.155 0. origin y=-17.464 z=0.15 rotate a2=-1.35
'*** four is item 2 in drawing 84-10649 ornl/csd/tm-220 ***
  cylinder 40 4.555 12.918 0.        origin x=-12.176 y=-9.343 z=0.111 rotate a1=-52.5 a2=-1.400
'*** five is item 3 in drawing 84-10649 ornl/csd/tm-220 ***
  cylinder 50 5.761 13.475 0.        origin x=-16.333 y=1.681 z=0.174 rotate a1=83.5 a2=+1.173
'*** six is item 4 in drawing 84-10649 ornl/csd/tm-220 ***
  cylinder 60 4.5525 12.969 0.    origin x=-9.539 y=11.168 z=0.156 rotate a1=40.5 a2=+1.970
'*** seven and eight are item 5 in drawing 84-10649 ornl/csd/tm-220 ***
'seven
  cuboid  70  2p3.81 8.13 -4.573 8.91 0. origin y=15.698 z=0.290 rotate a2=+2.58
'eight
  cylinder 80 4.573 13.229 8.91   origin y=15.698 z=0.290 rotate a2=+2.58
'*** nine is item 6 in drawing 84-10649 ornl/csd/tm-220 ***
  cylinder 90 4.5545 12.974 0.    origin x=9.854 y=10.964 z=0.134 rotate a1=-42.0 a2=+1.680
'*** ten is item 7 in drawing 84-10649 ornl/csd/tm-220 ***
  cylinder 100 5.7495 13.475 0.    origin x=16.388 y=1.434 z=0.140 rotate a1=-86.0 a2=+1.400
'*** eleven is item 8 in drawing 84-10649 ornl/csd/tm-220 ***
  cylinder 110 4.5565 12.954 0.    origin x=12.029 y=-9.398 z=0.087 rotate a1=38.0 a2=-1.100
'*12 through 14 is the centerpiece in drawing 84-10649 ornl/csd/tm-220
'twelve
  cylinder 120 5.757 2.690 0.      origin x=-0.593 y=-0.593 z=-1.753
'thirteen
  cuboid 130 4p6.35 5.718 0.       origin z=0.937
'fourteen
  sphere    140 6.082 chord +z=0.   origin x=-0.268 y=0.268 z=6.655
'*** fifteen is the system boundary ***
'fifteen
  cuboid   150 4p25.0 15.0 -2.0
  media  1 1 +10       vol=20.58546556
  media  2 1 +20 -10   vol=245.678420867
  media  3 1 +30 -20   vol=1800.040061395
  media  4 1 +40       vol=842.019046637
  media  5 1 +50       vol=1404.99376489
  media  6 1 +60       vol=844.415646269
  media  7 1 +70       vol=862.4600226
  media  8 1 +80 -70   vol=283.749744681
  media  9 1 +90       vol=845.483582679
  media 10 1 +100      vol=1399.390119093
  media 11 1 +110      vol=844.921798001
  media 12 1 +120 -130 vol=280.088070346
  media 13 1 +130      vol=922.25622
  media 14 1 +140 -130 vol=471.191948666
  media 0 1 150 -10 -20 -30 -40 -50 -60 -70 -80 -90 -100
            -110 -120 -130 -140  vol=31432.726088316
  boundary 150
end geom
read plot
  scr=yes  lpi=10
           clr= 1 255   0   0
                2   0   0 205
                3   0 229 238
                4   0 238   0
                5 205 205   0
                6 255 121 121
                7 145  44 238
                8 150 150 150
                9 240 200 220
               10   0 191 255
               11 224 255 255
               12   0 128  64
               13 255 202 149
               14 255   0 128
            end color
  ttl='grotesque x-y slice at z=0.5'
  xul=-25.5 yul= 25.5 zul=0.5
  xlr= 25.5 ylr=-25.5 zlr=.5
  uax=1     vdn=-1  nax=800 end
  ttl='grotesque x-y slice at z=2.0'
  xul=-25.5 yul= 25.5 zul=2
  xlr= 25.5 ylr=-25.5 zlr=2 end
  ttl='grotesque x-y slice at z=9.5'
  xul=-25.5 yul= 25.5 zul=9.5
  xlr= 25.5 ylr=-25.5 zlr=9.5 end
  ttl='grotesque y-z slice at x=-0.593'
  xul=-.593 yul=-25.5 zul=15.5
  xlr=-.593 ylr= 25.5 zlr=-3.5
  uax=0     vax=1
  vdn=0     wdn=-1 nax=800  end
  ttl='grotesque x-z slice at y=0.0'
  xul=-25.5 yul=0.0  zul=15.5
  xlr= 25.5 ylr=0.0  zlr=-3.5
  uax=1     vax=0    wax=0
  udn=0     vdn=0    wdn=-1 nax=800  end
  ttl='grotesque x-z slice at y=12.125'
  xul=-25.5 yul=12.125  zul=15.5
  xlr= 25.5 ylr=12.125  zlr=-3.5
  uax=1     vax=0       wax=0
  udn=0     vdn=0       wdn=-1 nax=800  end
  ttl='grotesque x-z slice at y=-12.000'
  xul=-25.5 yul=-12.000  zul=15.5
  xlr= 25.5 ylr=-12.000  zlr=-3.5
  uax=1     vax=0        wax=0
  udn=0     vdn=0        wdn=-1 nax=800  end
end plot
end data
end

Sample Problem 8 Infinite Array of MOX and UO2 Assemblies

The purpose of this problem is to calculate the keff of a system composed of an infinite array of MOX assemblies interspersed between UO2 assemblies. Both assembly types contain 331 pins in a hexagonal lattice with a pin pitch of 1.275 cm and an assembly pitch of 23.60 cm as shown in Fig. 94. The moderator is borated water at 306°C having a density of 0.71533 gm/cc and composed of 99.94 wt % H2O and 0.06 wt % natural boron. Each fuel rod is 355 cm in length, has a radius of 0.3860 cm, 0.722-cm-thick Zr cladding with no gap, and is at a temperature of 754°C.

The UO2 fuel consists of 4.4 wt % 235U and 95.6 wt % 238U at a density of 8.7922 gm/cc. The UO2 fuel also contains 9.4581E–9 atoms/b-cm of 135Xe and 7.3667E–8 atoms/b-cm of 149Sm.

The MOX fuel consists of 96.38 wt % UO2 and 3.62 wt % PuO2 at a density of 8.8182 gm/cc. The UO2 fuel is composed of 2.0 wt % 235U and 98.0 wt % 238U. The PuO2 fuel is composed of 93.0 wt % 239Pu, 6.0 wt % 240Pu- and 1.0 wt % 241Pu. The MOX fuel also contains 9.4581E–9 atoms/b-cm of 135Xe and 7.3667E–8 atoms/b-cm of 149Sm.

These two assemblies are placed so they represent an infinite array in the X and Y dimensions as shown in Fig. 95. There is 20 cm of water above and below fuel assemblies. This problem uses CENTRM/PMC as the resolved resonance processor cross section. Since an infinite array cannot be explicitly modeled, a section of the array is modeled and the X and Y sides have mirror reflection.

=csas6        parm=(centrm)
sample problem 8 - VVER inf. array - MOX & UO2 Assemblies
v7-238
read comp
'  UO2 Fuel
    uo2     1 den=8.7922 1.0 1027 92235 4.4  92238 95.6 end
    xe-135  1 0 9.4581E-09 1027 end
    sm-149  1 0 7.3667E-08 1027 end
'  MOX Fuel
    uo2     2 den=8.8182 0.9638 1027  92235  2.0 92238 98.0 end
    puo2    2 den=8.8182 0.0362 1027  94239 93.0 94240  6.0 94241  1.0 end
    xe-135  2 0 9.4581E-09 1027 end
    sm-149  2 0 7.3667E-08 1027 end
'  Cladding for UO2 fuel
    zr      3 den=6.4073 1.0  579  end
'  Moderator for UO2 fuel
    h2o     4 den=0.71533 0.9994 579 end
    boron   4 den=0.71533 0.0006 579 end
'  Cladding for MOX fuel
    zr      5 den=6.4073 1.0  579  end
'  Moderator for MOX fuel
    h2o     6 den=0.71533 0.9994 579 end
    boron   6 den=0.71533 0.0006 579 end
'  Moderator for vacant units
    h2o     7 den=0.71533 0.9994 579 end
    boron   7 den=0.71533 0.0006 579 end
end comp
read celldata
  latticecell triangpitch pitch=1.2750 4 fueld=0.7720 1 cladd=0.9164 3 end
  latticecell triangpitch pitch=1.2750 6 fueld=0.7720 2 cladd=0.9164 5 end
'  more data  dab=500  end more
end celldata
read param
  gen=203  npg=1000
end param
read bounds
  all=mirror zfc=void
end bounds
read geom
  unit   1
   com='UO2 Fuel Rod'
   cylinder 10 0.3860 355.0 0.0
   cylinder 20 0.4582 355.0 0.0
   hexprism 30 0.6375 355.0 0.0
   media 1 1 10
   media 3 1 20 -10
   media 4 1 30 -20
   boundary 30
  unit  2
   com='Vacant(water filled) hex'
   hexprism 10 0.6375 355.0 0.0
   media 7 1 10
   boundary 10
  unit  3
   com='Vacant(water filled) hex'
   hexprism 10 0.6375 355.0 0.0
   media 7 1 10
   boundary 10
  unit   4
   com='MOX Fuel Rod'
   cylinder 10 0.3860 355.0 0.0
   cylinder 20 0.4582 355.0 0.0
   hexprism 30 0.6375 355.0 0.0
   media 2 1 10
   media 5 1 20 -10
   media 6 1 30 -20
   boundary 30
  global unit 5
   rhexprism 10 11.800 355.0 0.0
   rhexprism 20 11.800 355.0 0.0 origin y=23.6
   rhexprism 30 11.800 355.0 0.0 origin x=20.4382 y=11.8
   rhexprism 40 11.800 355.0 0.0 origin x=20.4382 y=35.4
   cuboid   50 20.4382 0.0 35.4 0.0 375.0 -20.0
   array 1  10 -20 -30 -40 place 12 12 1  0.0       0.0  0.0
   array 2  20 -10 -30 -40 place 12 12 1  0.0      23.6  0.0
   array 2  30 -10 -20 -40 place 12 12 1  20.4382  11.8  0.0
   array 1  40 -10 -20 -30 place 12 12 1  20.4382  35.4  0.0
   media 4 1 50 -10 -20 -30 -40
   boundary 50
end geom
read array
  ara=1 typ=shexagonal nux=23 nuy=23 nuz=1
    fill
   3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3
    3 3 3 3 3 3 4 4 4 4 4 4 4 4 4 4 4 3 3 3 3 3 3
   3 3 3 3 3 3 4 4 4 4 4 4 4 4 4 4 4 4 3 3 3 3 3
    3 3 3 3 3 4 4 4 4 4 4 4 4 4 4 4 4 4 3 3 3 3 3
   3 3 3 3 3 4 4 4 4 4 4 4 4 4 4 4 4 4 4 3 3 3 3
    3 3 3 3 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 3 3 3 3
   3 3 3 3 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 3 3 3
    3 3 3 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 3 3 3
   3 3 3 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 3 3
    3 3 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 3 3
   3 3 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 3
    3 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 3
   3 3 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 3
    3 3 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 3 3
   3 3 3 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 3 3
    3 3 3 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 3 3 3
   3 3 3 3 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 3 3 3
    3 3 3 3 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 3 3 3 3
   3 3 3 3 3 4 4 4 4 4 4 4 4 4 4 4 4 4 4 3 3 3 3
    3 3 3 3 3 4 4 4 4 4 4 4 4 4 4 4 4 4 3 3 3 3 3
   3 3 3 3 3 3 4 4 4 4 4 4 4 4 4 4 4 4 3 3 3 3 3
    3 3 3 3 3 3 4 4 4 4 4 4 4 4 4 4 4 3 3 3 3 3 3
   3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3
    end fill
  ara=2 typ=shexagonal nux=23 nuy=23 nuz=1
    fill
   2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2
    2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2
   2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2
    2 2 2 2 2 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2
   2 2 2 2 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2
    2 2 2 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2
   2 2 2 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2
    2 2 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2
   2 2 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2
    2 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2
   2 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2
    2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2
   2 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2
    2 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2
   2 2 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2
    2 2 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2
   2 2 2 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2
    2 2 2 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2
   2 2 2 2 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2
    2 2 2 2 2 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2
   2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2
    2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2
   2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2
    end fill
end array
read plot
  lpi=10 scr=yes
  ttl='VVER assembly x-y x-section'
  xul=-0.1  yul=35.5  zul=10
  xlr=20.6  ylr=-0.1  zlr=10
  uax=1     vdn=-1.0
  nax=640   pic=mat   end plt1
end plot
read volume
    type=random  batches=1000
end volume
end data
end
_images/fig4.png

Fig. 94 MOX or UO2 hexagonal assembly.

_images/fig5.png

Fig. 95 Infinite array of MOX assemblies interspersed between UO2 assemblies.

Warning and Error Messages

CSAS6 contains two types of warning and error messages. The first type of message is from XSProc is common to many of the SCALE analytical sequences. The second type of message is from the CSAS6 subroutines and is identified by CS- followed by a number. These messages are listed in numerical order below. For additional information concerning a message, simply look up the number in this section.

Warning messages appear when a possible error is encountered. It is the responsibility of the user to verify whether the data are correct when a warning message is encountered. The functional modules activated by CSAS6 and related sequences will be executed even though a warning message has been generated.

When an error is recognized, an error message is written and an error flag is set so the functional modules will not be activated. The code stops immediately if the error is too severe to allow continuation of input. However, it will continue to read and check the data if it is able. When the data reading is completed, execution is terminated if an error flag was set when the data were being processed. If the error flag has not been set, execution continues. When error messages are printed, the user should focus on the first error message, because subsequent messages may have been caused by the error that generated the first message.

The following messages originate in the part of CSAS6 that reads, checks, and prepares data for KENO‑VI. The same set of error messages are also used for CSAS5 that reads, checks, and prepares data for KENO V.a and MODIFY. CSAS6 is not capable of performing searches at this time. An error message referring to a SEARCH routine, from a CSAS6 problem, indicates a code error.

CS-16 ***WARNING*** READ FLAG NOT FOUND. ASSUME KENO V PARAMETER DATA FOLLOWS.

This message from subroutine CPARAM indicates that the word READ is not the first word of KENO-VI data following the Material Information Processor input data. If parameter data is to be entered, the code expects the words READ PARAMETERS to precede the parameter input data. If the word READ is not the first word, the code assumes the data are parameter input data.

CS-21 A UNIT NUMBER WAS ENTERED FOR THE CROSS-SECTION LIBRARY. (LIB= IN PARAMETER DATA.) THE DEFAULT VALUE SHOULD BE USED IN ORDER TO UTILIZE THE CROSS SECTIONS GENERATED BY CSAS. MAKE CERTAIN THE CORRECT CROSS-SECTION LIBRARY IS BEING USED.

This message is from subroutine CPARAM. It indicates that a value has been entered for the cross-section library in the KENO-VI parameter data. The cross-section library created by the analytical sequence should be used. MAKE CERTAIN THAT THE CORRECT CROSS SECTIONS ARE BEING USED.

CS-55 *** ERRORS WERE ENCOUNTERED IN PROCESSING THE CSAS-KENO6 DATA. EXECUTION IS IMPOSSIBLE. ***

This message from subroutine SASSY is printed if errors were found in the KENO-VI input data for CSAS. If a search is being made, data reading will continue until all the data have been entered or a fatal error terminates the data reading. When the data reading and checking have been completed, the problem will terminate without executing. Check the printout to locate the errors responsible for this message.

CS-62 *** ERROR *** MIXTURE ______ IN THE GEOMETRY WAS NOT CREATED IN THE STANDARD COMPOSITIONS SPECIFICATION DATA.

This message from subroutine MIXCHK indicates that a mixture specified in the KENO-VI geometry was not created in the standard composition data.

CS-68 *** ERROR *** AN INPUT DATA ERROR HAS BEEN ENCOUNTERED IN THE DATA ENTERED FOR THIS PROBLEM.

This message from the main program, CSAS6, is printed if the subroutine library routine LRDERR returns a value of “TRUE,” indicating that a reading error has been encountered in the “KENO PARAMETER” data. The appropriate data type is printed in the message. Locate the unnumbered message stating “*** ERROR IN INPUT. CARD IMAGE PRINTED ON NEXT LINE ***.” Correct the data and resubmit the problem.

CS-69 ***ERROR*** MIXTURE ______ IS AN INAPPROPRIATE MIXTURE NUMBER FOR USE IN THE KENO GEOMETRY DATA BECAUSE IT IS A COMPONENT OF THE CELL-WEIGHTED MIXTURE CREATED BY XSDRNPM.

This message from subroutine CMXCHK indicates that a mixture that is a component of a cell-weighted mixture has been used in the KENO-VI geometry data.

CS-82 *** AN ERROR WAS ENCOUNTERED IN ONE OF THE FUNCTIONAL MODULES.

This message from CSAS6 indicates that an error was encountered during execution of one of the functional modules such as CRAWDAD, BONAMI, CENTRM, PMC, XSDRNPM, or KENO-VI. Check the printout to locate and correct the error.

CS-99 THIS PROBLEM WILL NOT BE RUN BECAUSE PARM=CHECK WAS ENTERED IN THE ANALYTICAL SEQUENCE SPECIFICATION.

This message from subroutine CSAS indicates that the problem data were read and checked and no errors were found. To execute the problem, remove the PARM=CHECK or PARM=CHK from the analytical sequence indicator data entry.

CS-100 THIS PROBLEM WILL NOT BE RUN BECAUSE ERRORS WERE ENCOUNTERED IN THE INPUT DATA.

This message from subroutine CSAS is self-explanatory. Examine the printout to locate the error or errors in the input data. Correct them and resubmit the problem.

Mih99

J. T. Mihalczo. Brief summary of unreflected and unmoderated cylindrical critical experiments with oralloy at Oak Ridge. Technical Report, Oak Ridge National Lab., Oak Ridge, TN (US), 1999.