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SCALE v6.1.3

This release of SCALE is unsupported. Please click here for the current production release.

 

SCALE 6.1.3 Updates

The SCALE 6.1.3 update is available for SCALE 6.1 to provide enhanced performance in the areas detailed below.  This comprehensive update includes enhancements previously released as SCALE 6.1.1 and SCALE 6.1.2.  In addition to the functionality improvements provided in 6.1.1 and 6.1.2, the SCALE 6.1.3 update provides compatibility with additional Linux operating systems, but provides no additional updates in functionality. This update is recommended for all users of SCALE 6.1 and 6.1.1 and for Linux users of 6.1.2.

Segmentation Fault on Some Linux Kernels

SCALE 6.1, 6.1.1, and 6.1.2 were created and tested on RHEL4 Linux to provide backwards compatibility with older Linux operating systems.  Users of newer Linux kernels have reported problems executing SCALE, with all modules stopping on a segmentation fault. Although ORNL only has a few variants of Linux for testing, the error is believed to occur on Ubuntu 11, 12, 13; Fedora 16, 17, 18; RHEL6; and CentOS 6.4.

The issue is caused by changes in how Linux handles system calls that report environment information used to populate the SCALE QA table.

SCALE 6.1.3 provides revised methods to access this information and the compiled binary executable files for 64-bit Linux systems are compatible with many more operating systems.  No further enhancements to SCALE are provided with this update, so previously computed results will not vary beyond normal statistical deviations observed when updating compilers and/or operating systems.

Mac and Windows users are not affected by this update, so the Mac, Windows and 32-bit Linux executable files in SCALE 6.1.3 are the same as those distributed with SCALE 6.1.2.

 

SCALE 6.1.3 Known Issues

The identified issues in SCALE 6.1.3 are presented below, along with suggested user approaches to overcome existing limitations.

KENO V.a Requires Cuboidal Outermost Region to Enable the Use of Albedo Boundary Conditions

In all versions of SCALE, the Monte Carlo code KENO V.a only implements the use of non-vacuum albedo boundary conditions (e.g., mirror, periodic, white) when the outermost geometry region of the model is a cuboidal region. This limitation is noted in the user documentation in the section on Albedo data, where it is stated that “Albedo boundary conditions are applied only to the outermost region of a problem. In KENO V.a this geometry region must be a rectangular parallelepiped.”

It was recently discovered that—beginning with the release of SCALE 6.1 in 2011—KENO V.a will accept non-compliant input that specifies albedo boundary conditions for non-cuboidal outer shapes and will then attempt to complete the calculation. For example, a user can specify a cylinder as the outermost region and add a mirror boundary condition on the top or bottom to effectively double the volume of the system considered. A user could also add a mirror boundary condition to both the top and the bottom of the cylinder to simulate a bounding case of an infinite system. While these scenarios are accepted and perform as expected in KENO-VI, KENO V.a requires the addition of a cuboidal region (typically an empty void region) to enable the use of these albedo boundary conditions.

For calculations using KENO V.a in SCALE 6.1–6.2.2 with non-compliant input in which albedo boundary conditions are applied but without the required cuboidal outermost region, the calculation will proceed without warning, and an underestimation of k-eff often results. The magnitude of underestimation in k-eff can vary widely, depending on the system modeled and the desired boundary conditions, but it can exceed several percent in k-eff.

It is strongly recommended that users who rely on albedo boundary conditions in KENO V.a review their input models to ensure that the outermost region is a cube or cuboid, per the documentation requirement. Note that input models that were generated and applied with SCALE 6 and earlier versions that included the check for the cuboidal outer boundary will continue to produce the expected results with SCALE 6.1–6.2.2.

In testing the extent of this issue by placing mirror boundary conditions on non-cuboidal outer shapes, it was found that cylinders oriented along the x-, y-, or z-axis most often produce non-conservative results without warning. The calculation will terminate prior to completion for cases in which a sphere is the outermost shape. The calculation will terminate with an error message for cases in which a hemicylinder or hemisphere is the outermost shape. The calculation performs as expected for cases in which a cube or cuboid is the outermost shape.

This issue applies to all SCALE 6.1–6.2.2 sequences that implement KENO V.a, including CSAS5, TSUNAMI-3D-K5, T5-DEPL, and STARBUCS. No other SCALE sequences are impacted by this issue. The error condition for the attempted use of albedo boundary conditions on non-cuboidal outer shapes in KENO V.a will be restored in the pending release of SCALE 6.2.3, thus preventing users from inadvertently entering non-compliant input.

ORIGEN Input Concentrations for Stream Blending Calculation

An error was reported in the stream blending option of ORIGEN in SCALE 6.1. Other previous versions are not affected. As documented in the user manual, the NGO parameter indicates the type of subcase that follows the current calculation so that appropriate data are retained. When the blended compositions from previous subcases are requested as the starting concentrations in the current subcase (KBLEND = -1), the value of NGO in the preceding subcase should request the blended concentrations using NGO = -1. However, this option results in some streams being omitted from the starting concentrations in the blended case. The use NGO = 1 in the prior subcase, instead of NGO = -1, avoids this issue and the concentrations from all blended streams are retained. However, this use of NGO is inconsistent with the user manual.

It is important that users verify that the blended stream compositions by printing the concentrations of the streams before and after blending. The blending example case shown in Section F7.6.5 of the SCALE Manual has been modified to function correctly. The use of NGO = -1 in this example results in the fuel compositions being omitted from the glass matrix composition. The revised input should be as follows:

=origen
1$$ 2 1t
pwr nuclear data library
2** 2r 1.0
3$$ 33 a4 44 a16 2 a33 18 e 2t
35$$ 0 4t
56$$ 10 10 a13 5 4 3 0 2 1 e 57** a3 1-14 e 5t
pwr - 3.2% enriched u
40 kg U
58** 10r1.2 60** 8i110 1100
61** f 1e-6
66$$ a5 2 a9 2 e
73$$ 922340 922350 922360 922380 80000
74** 11.48 1280. 0.44 38708. 5382.3
75$$ 4r2 4
6t
'
' decay the irradiation fuel composition and apply removal fractions
56$$ 0 10 a6 -1 a10 -10 a15 0 a17 4 a20 10 e 5t
60** 3 5 10 30 60 90 120 160 270 365
65$$ a4 1 a25 1 a46 1 e
61** f1-3
' Keep Se, Dy (99.8%); Rb, Sr, Te, Cs, Ba (77.8%); and U, Np, Pu, Am, Cm (1%)
79** f0 a34 0.998 a37 0.778 a38 0.778 a52 0.778 a55 0.778 a56 0.778
a66 0.998 a92 0.01 a93 0.01 a94 0.01 a95 0.01 a96 0.01 e
6t
'
' define glass matrix compositions
56$$ 0 1 a6 1 a10 0 a13 15 a15 2 a17 4 a20 1 <--- previously was a6 -1
57** 0 a3 1e-05 e t
100 kg glass
60** 1 61** f0.001
65$$ a4 1 1 a25 1 a46 1 e
' Li, B, O, F, Na, Mg, Al, Si, Cl, Ca, Mn, Fe, Ni, Zr, Pb
73$$ 30000 50000 80000 90000 11000 12000 13000 140000 170000
200000 250000 260000 280000 400000 820000
74** 2180 2110 46400 61 7650 490 2180 25400 49 1080
1830 8610 700 880 49
75$$ 15r 4
6t
'
54$$ a11 2 e
56$$ a2 1 a6 1 a10 0 a15 3 a17 2 a20 -1 e
57** 1 a3 1e-05 e t
final blended case
100 kg U
60** 2
61** f0.001
65$$ a4 1 a25 1 a46 1 e
' use default 18-group gamma energy structure
81$$ 2 0 26 1 e
82$$ 2 e
' 44 neutron energy group structure
84**
2.0000000e+07 8.1873000e+06 6.4340000e+06 4.8000000e+06
3.0000000e+06 2.4790000e+06 2.3540000e+06 1.8500000e+06 1.4000000e+06
9.0000000e+05 4.0000000e+05 1.0000000e+05 2.5000000e+04 1.7000000e+04
3.0000000e+03 5.5000000e+02 1.0000000e+02 3.0000000e+01 1.0000000e+01
8.1000000e+00 6.0000000e+00 4.7500000e+00 3.0000000e+00 1.7700000e+00
1.0000000e+00 6.2500000e-01 4.0000000e-01 3.7500000e-01 3.5000000e-01
3.2500000e-01 2.7500000e-01 2.5000000e-01 2.2500000e-01 2.0000000e-01
1.5000000e-01 1.0000000e-01 7.0000000e-02 5.0000000e-02 4.0000000e-02
3.0000000e-02 2.5300000e-02 1.0000000e-02 7.5000000e-03 3.0000000e-03
1.0000000e-05 e
6t
56$$ f0 t
end

Date Identified: 05/20/2014; Date Resolved: 08/13/2014

Problems with SCALE 6.1 Installer with Java 7

The IZPack installer distributed with SCALE 6.1 was created using Java 6. With Java 7 now being deployed by many IT departments to address issues with Java 6, the behavior of the SCALE 6.1 installer has changed.

The instructions provided in the Scale6.1_Readme file states:

To begin installation of SCALE 6.1 for Windows, double-click the scale-6.1-setup.jar file on the DVD. Linux and Mac systems will not allow the first installation disk to eject if the install program is running from the DVD. For Linux or Mac, copy the scale-6.1-setup.jar to your local disk and double-click the local version or issue the following command java –jar scale-6.1-setup.jar in the location where the installer .jar file was copied.

Revised instructions for use with Java 7 are:

To begin installation of Scale 6.1 for Windows, Linux, and Mac systems copy the scale-6.1-setup.jar to your local disk and issue the following command from the Command Prompt (DOS Window) or Terminal:

java –jar scale-6.1-setup.jar -direct in the location where the installer .jar file was copied. The -direct option resolves issues associated with Java 7 but is not available when double-clicking the .jar file for installation.

Date Identified: 05/08/2013; Date Resolved: 09/13/2013

NEWT Mesh Generator Issue for Hexagonal Geometries

An issue in NEWT’s automatic mesh generation routines was recently identified for hexagonal-array geometries. In certain instances, NEWT will place an incorrect material in a computational cell of the problem. The issue can be identified by inspecting the “newtmatl.ps” file that is generated when the NEWT parameter option “drawit=yes” is enabled. When viewing this file, some computational cells may appear as a different color compared to adjacent cells, as shown in the figure below.

 

Illustration of the NEWT mesh generator issue for hexagonal geometries (top) and the same model constructed using holes (bottom).

In order to circumvent this issue, it is recommended that users construct hexagonal geometries by placing fuel pins using holes rather than an array. Using holes should eliminate the issue and provide a computational speedup due to a reduction in computational cells versus using an array.

Date Identified: 09/13/2013