.. _sec-scale.intro: ============ Introduction ============ **W. A. Wieselquist** .. sectionauthor:: W. A. Wieselquist The SCALE code system includes verified and validated tools for criticality safety, reactor physics, radiation shielding, radioactive source characterization, and sensitivity and uncertainty analysis. SCALE is developed, maintained, tested, and managed by Oak Ridge National Laboratory (ORNL) and may be obtained through the Radiation Safety Information Computational Center (RSICC). This manual documents version 6.3 of the SCALE code system, with initial release of 6.3.0 in 2022. The previous 6.2 series had its last maintenance release, 6.2.4, in 2020. This section describes the key features in 6.3 relative to 6.2 and details on how to run SCALE. Maintenance releases of SCALE 6.3 (6.3.1, 6.3.2, etc.) will be made as needed to fix any issues discovered. Historically, there has been approximately one maintenance release per year. Note that once users have been granted a license from RSICC, any subsequent maintenance releases may be obtained free of charge directly from the SCALE team by sending an email to scalehelp@ornl.gov. The next major release of SCALE with additional features will be SCALE 7.0 in ~2025. The SCALE manual is included with installation; however, an online version is also available. The online version is new as of SCALE 6.3 and is in a convenient format for users, containing detailed lists of changes as well as any issues discovered in a particular version, starting with SCALE 6.3.0. Instructions on installing or building SCALE, testing the configuration with the sample problems are available in :numref:`sec-scale.install`. Organization ------------ SCALE's top-level applications have been historically called "sequences" because of their original design, which called specific modules in sequence to solve specific problems. With the development of SCALE 6.3, we have found it more useful to think of SCALE as a set of products. A product is potentially more than one sequence and attempts to logically group capabilities around a particular application area. This is useful both from the standpoint of helping a user identify which sequences they should use and from a development point of view, as domain experts are assigned to each product. See :numref:`tab-scale.app_areas` for the relationships between end user applications, SCALE products, and sequences. .. tabularcolumns:: | p{5cm} | p{2cm} | p{4cm} | .. table:: Relationship between end-user applications, SCALE products, and sequences :class: longtable :name: tab-scale.app_areas +-----------------------------+---------+-------------------+ | End user Application Area | Product | Example Sequences | +=============================+=========+===================+ | Reactor Physics | Polaris | ``polaris`` | | +---------+-------------------+ | | TRITON | ``t-depl`` | | | | | | | | ``t5-depl`` | | | | | | | | ``t5-depl`` | | | | | | | | ``t-depl-1d`` | | | | | +-----------------------------+---------+-------------------+ | Criticality Safety | CSAS | ``csas5`` | | | | | | | | ``csas6`` | | +---------+-------------------+ | | VADER | ``vader`` | +-----------------------------+---------+-------------------+ | Spent Fuel Inventory | ORIGAMI | ``origami`` | | +---------+-------------------+ | | ORIGEN | ``arp`` | | | | | | | | ``origen`` | +-----------------------------+---------+-------------------+ | Activation and Decay | ORIGEN | ``couple`` | | | | | | | | ``origen`` | +-----------------------------+---------+-------------------+ | Radiation Shielding | MAVRIC | ``mavric`` | +-----------------------------+---------+-------------------+ | Sensitivity and Uncertainty | TSUNAMI | ``tsunami-3d-k5`` | | | | | | | | ``tsunami-3d-k6`` | | | | | | | | ``tsunami-ip`` | | | | | | | | ``tsar`` | | | | | | | | ``tsurfer`` | | | | | | | | ``tsunami-1d`` | | | | | | | | ``tsunami-2d`` | | +---------+-------------------+ | | Sampler | ``sampler`` | +-----------------------------+---------+-------------------+ The reconceptualization of sequences as products also facilitates management and discussion of certain key SCALE components, such as nuclear data. :numref:`tab-scale.prods_guide` briefly describes each product and contains links to the relevant section(s) in the manual. .. tabularcolumns:: | p{2cm} | p{7cm} | p{5cm} | .. csv-table:: SCALE Products :class: longtable :name: tab-scale.prods_guide :file: Products.csv :delim: | :header-rows: 1 SCALE 6.3 Updates by Product ---------------------------- The new features relative to SCALE 6.2 are described below, organized in terms of products as shown in :numref:`tab-scale.prods_guide`. Fulcrum ~~~~~~~ The major new feature in Fulcrum is the 3D visualization of geometry, including results overlay capability. .. figure:: figs/fulcrum-3d-vis.png :align: center :width: 45% :name: fig-fulcrum.examples.3dvis.png Fulcrum visualization of geometry including new 3D. .. figure:: figs/fulcrum-fhr-flux.png :align: center :width: 27% :name: fig-fulcrum.examples.fhr_flux.png Fulcrum visualization of 3D reactor geometry with flux overlay. CSAS ~~~~ The key new CSAS feature in 6.3 is the ability to call Shift for neutron transport. The same CSAS user interface is available for both CSAS-KENO and CSAS-Shift, and the majority of KENO features are supported by Shift. See :numref:`sec-csas-shift` for details. - CSAS-KENO now allows specification of the upper thermal scattering cutoff energy. A value above the default 10 eV may be necessary for high-temperature graphite--moderated systems. See :numref:`sec-module.keno.ce_physics.tsl` for details. - CSAS now supports reusable energy and spatial grid definitions in the ``definitions`` block, especially useful for producing \*.3dmap files for visualization in Fulcrum. See :numref:`sec-csas.def` for details. - Shift can randomly place spheres within volumes, also useful for tristructural isotropic (TRISO) packing in pebbles. See :numref:`sec-module.shift.randomgeom` for details. VADER ~~~~~ VADER is the modernization of the trending analysis code USLStats previously externally distributed with SCALE. VADER uses the SON input format introduced in SCALE 6.2. See :numref:`sec-vader` for details. MAVRIC ~~~~~~ The key new MAVRIC feature in 6.3 is the ability to call Shift for neutron and gamma transport. Append ``-shift`` to the sequence name to use Shift as in the example below. .. code-block:: scale =mavric-shift Leakage spectrum of Cf-252 through a heavy water sphere v7.1-28n19g read composition d2o 1 0.99286 293.0 end h2o 1 0.00714 293.0 end polyethylene 2 0.882 293.0 end boron 2 0.118 293.0 end iron 3 1.0 293.0 end orconcrete 4 1.0 293.0 end end composition '------------------------------------------------------------------------------- ' Geometry Block '------------------------------------------------------------------------------- read geometry global unit 1 sphere 10 0.5 sphere 11 15.0 sphere 21 2.0 origin x=75.0 cuboid 41 650.0 -650 500 -500 2300 -200 cuboid 42 750.0 -750 600 -600 2400 -300 media 0 1 10 media 1 1 11 -10 media 0 1 21 vol=33.510322 media 0 1 41 -11 -21 media 4 1 42 -41 boundary 42 end geometry '------------------------------------------------------------------------------- ' Definitions Block '------------------------------------------------------------------------------- read definitions distribution 1 title="Cf-252 neutrons, Watt spectrum a=1.025 MeV and b=2.926/MeV" special="wattSpectrum" parameters 1.025 2.926 end end distribution end definitions '------------------------------------------------------------------------------- ' Sources Block ' Cf-252 neutrons, Watt fission spectrum model ' strength set so that total unattenuated flux at detector would be 1 ' strength = 4*pi*(75)^2 '------------------------------------------------------------------------------- read sources src 1 title="Cf-252 neutrons, Watt fission spectrum, using a=1.025 and b=2.926" neutrons strength=70685.834704 sphere 0.1 eDistributionID=1 end src end sources '------------------------------------------------------------------------------- ' Tallies Block '------------------------------------------------------------------------------- read tallies regionTally 3 title="example region tally" neutron unit=1 region=3 end regionTally end tallies '------------------------------------------------------------------------------- ' Parameters Block '------------------------------------------------------------------------------- read parameters randomSeed=8655745262010033 batches=10 neutrons noPhotons fissionMult=0 secondaryMult=0 ' speed things up for the sample problem perBatch=20000 end parameters end data end .. note:: Some features in MAVRIC using the default Monaco transport engine are not yet available in Shift. TRITON ~~~~~~ TRITON was updated with a host of new capabilities in SCALE 6.3. - TRITON can now call the new Shift Monte Carlo code instead of KENO. Shift was designed with parallelism and robustness as the highest priorities. With Shift enabled, few-group macroscopic cross sections on 3D hex and Cartesian meshes can be generated, similar to but more general than existing capabilities in TRITON-NEWT and Polaris. See :numref:`sec-triton.fgxs` for details. - Shift can randomly place spheres within volumes, which is available in both CSAS-Shift and TRITON-Shift. See :numref:`sec-module.shift.randomgeom` for details. - A new flow block has been added to the TRITON timetable, intended for simulating molten salt reactors. See :numref:`sec-triton.timetable.mat_flow` for details. Polaris ~~~~~~~ The main Polaris improvement for 6.3 is a noticeable decrease in runtime, by a factor of 3 to 5 for almost all use cases. This was enabled through numerous performance-related refactors of the geometry, transport, and self-shielding components. In addition, the following updates were made. - Additional accident-tolerant fuel compositions (see :numref:`sec-polaris.comps`) and new dopant properties (see :numref:`sec-polaris.property.dopant`). - Polaris can now generate ORIGEN library files (\*.f33) (see :numref:`sec-polaris.option.depl`). - Gamma detector modeling was added. - Output file was improved. See :numref:`sec-polaris.63_updates` for details on the updates. ORIGEN ~~~~~~ Extensive improvements to ORIGEN were made for SCALE 6.3, including the following. - Modernized library construction integrated into the ORIGEN sequence instead of external the COUPLE sequence (see :numref:`sec-origen.build_lib` for details). - Sensitivity analysis capability (see :numref:`sec-origen.sens` for details). - OBIWAN command line utility (see :numref:`sec-obiwan` for details). ORIGAMI ~~~~~~~ There were minimal changes to ORIGAMI for SCALE 6.3; however, the ORIGEN reactor library data has been refreshed and includes higher burnups and enrichments (see :numref:`sec-origen_rx` for details). XSProc ~~~~~~ The main changes to XSProc for SCALE 6.3 comprise adjustments to the default self-shielding parameters to reduce biases at high temperature and high burnup, as well as to improve the Bondarenko method accuracy for fuel models with multiple radial temperature zones. The input below demonstrates a lattice cell with multiple temperature rings using the fast Bondarenko-based self-shielding method (Bonami). .. code-block:: scale =csas6 parm=(bonami) mg-keno with bonami for nonuniform temperature v7.1-56 read comp uo2 1 den=10.97 1.0 1200.0 92235 5.0 92238 95.0 end uo2 2 den=10.97 1.0 1100.0 92235 5.0 92238 95.0 end uo2 3 den=10.97 1.0 1000.0 92235 5.0 92238 95.0 end uo2 4 den=10.97 1.0 900.0 92235 5.0 92238 95.0 end uo2 5 den=10.97 1.0 800.0 92235 5.0 92238 95.0 end uo2 6 den=10.97 1.0 700.0 92235 5.0 92238 95.0 end uo2 7 den=10.97 1.0 600.0 92235 5.0 92238 95.0 end helium 8 1.0 600.0 end zirc4 9 1.0 600.0 end h2o 10 den=0.661 1.0 600.0 end end comp read celldata latticecell squarepitch pitch=1.4427 10 fuelr=0.177473 1 fuelr=0.250985 2 fuelr=0.307393 3 fuelr=0.354946 4 fuelr=0.396842 5 fuelr=0.434719 6 fuelr=0.469550 7 gapr=0.479100 8 cladr=0.546400 9 end end celldata read param gen=200 nsk=100 npg=400000 sig=0.0001 far=yes end param read geometry global unit 1 cylinder 1 0.177473 1.0 -1.0 cylinder 2 0.250985 1.0 -1.0 cylinder 3 0.307393 1.0 -1.0 cylinder 4 0.354946 1.0 -1.0 cylinder 5 0.396842 1.0 -1.0 cylinder 6 0.434719 1.0 -1.0 cylinder 7 0.469550 1.0 -1.0 cylinder 8 0.479100 1.0 -1.0 cylinder 9 0.546400 1.0 -1.0 cuboid 10 6p0.72135 media 1 1 1 media 2 1 2 -1 media 3 1 3 -2 media 4 1 4 -3 media 5 1 5 -4 media 6 1 6 -5 media 7 1 7 -6 media 8 1 8 -7 media 9 1 9 -8 media 10 1 10 -9 boundary 10 end geometry read bounds all=mirror end bounds end data end DATA ~~~~ One of the main data updates for SCALE 6.3 is the inclusion of additional ENDF/B-VIII.0 data resources and the removal of ENDF/B-VII.0 data. New data resources include the following: - New ice and other compounds such as reactor-grade graphite present in ENDF/B-VIII.0. - Continuous-energy (CE) cross section data based on ENDF/B-VII.1 and ENDF/B-VIII.0. - New multigroup (MG) libraries for fast-spectrum and thermal-spectrum systems (reactivity and depletion results closer to higher fidelity CE results). See :numref:`sec-data` for details. Note that all 3D Monte Carlo codes in SCALE (TRITON, CSAS, MAVRIC) support both CE and MG methods. MG data and methods are faster but more approximate solutions. Sampler ~~~~~~~ Sampler includes considerable updates to help users understand the causes of uncertainty in their simulations. Updates include the following: - New sensitivity metrics for understanding nuclear data responsible for the majority of uncertainty (see :numref:`sec-sampler.r2` for details). - Ability to analyze uncertainty due to delayed neutron data using the new ``perturb_kinetics`` option. - A new analysis block which includes ability to calculate correlation coefficients between arbitrary outputs (see :numref:`sec-sampler.analysis` for details). TSUNAMI ~~~~~~~ For SCALE 6.3, the following enhancements were made to TSUNAMI. - New Shift-based iterated fission probability (IFP) method with better performance than previous KENO-based IFP and Clutch methods. - Improved performance of TSUNAMI-IP similarity and uncertainty calculations. - New general HDF5 format for the sensitivity coefficients (see :numref:`sec-tsunami.sdf.hdf5` for details). AMPX ~~~~ AMPX continues to be included in SCALE 6.3 and has been used exclusively to generate all libraries described in :numref:`sec-data`. The major enhancements were modernization related---to increase robustness of generated CE and MG libraries and to enable reading the new international GNDS data format. AMPX is now an open-source code system; the newest features are available by contacting the `AMPX team `_. Omnibus ~~~~~~~ Omnibus is the new frontend for the high-performance Shift Monte Carlo and Denovo deterministic transport codes that enables cutting-edge execution of Shift on GPU and Hybrid GPU/CPU platforms. As this capability evolves rapidly, please contact the authors of :cite:`pandya_shift_2016` for details on getting the latest version of this frontend and manual :cite:`johnson_omnibus_2020`. Removed Components in SCALE 6.3 ------------------------------- Three SCALE sequences have been removed in SCALE 6.3, - `SOURCERER``, - `STARBUCS``, and - `CSAS5S``. SOURCERER Alternatives ~~~~~~~~~~~~~~~~~~~~~~ `SOURCERER` was designed as a sequence that wraps a CSAS calculation with a starting source from a Denovo deterministic calculation. The hope was that this would accelerate convergence, however the utility for practical applications has been questionable. For SCALE 7.0, additional source convergence diagnostics are being developed and it is the intention that any techniques for starting sources would become part of the CSAS starting source specification, not their own sequence, and apply to both KENO and Shift. STARBUCS Alternatives ~~~~~~~~~~~~~~~~~~~~~~ `STARBUCS` is to a certain extent superseded by the UNF Standards system for generating spent fuel inventory and generating dry storage and transportation casks for criticality and shielding calculations. Although it is not a 1-to-1 replacement, as `STARBUCS` is designed specifically for burnup credit applications, the usership of `STARBUCS` appears to be quite low in recent years and there was little sponsor interest in funding the modernization. For SCALE 7.0, we are entertaining the idea that a burnup credit application could be built using functionality in Sampler and ORIGAMI and some of the key enhancements needed for this application would be useful in other areas as well. Those include the following. - Refocusing ORIGAMI on simply generating high-quality, annotated F71s. Annotated means that there is information about burnup, operating history, assembly type, and other data that can be used by downstream codes, e.g. ORIGAMI-generated axial zone-wise data can easily be translated to a 3D model - Develop tools to effectively translate that inventory to CSAS and MAVRIC models - Populating any SCALE mixture with data from an F71 - Generating composition blocks from an F71 - Add additional search capabilities to Sampler. CSAS5S Alternatives ~~~~~~~~~~~~~~~~~~~ The parametric study option in `Sampler` is the clear successor to `CSAS5S` search capability. With the parametric study, users are able to construct :math:`k_{eff}` curves as a function of any parameters in the model. SCALE 7.0 Sampler enhancements will enable surface reconstruction and some search capability which can be used in any sequence. Deprecated Components in SCALE 6.3 ---------------------------------- The following components are deprecated in SCALE 6.3 and are slated for removal in SCALE 7.0. - `COUPLE`: the FIDO-based ORIGEN library manipulator is currently superseded by the capabilities in the new ORIGEN `build_lib` block. Additional manipulation will be available using the `OBIWAN` command line utility. - `ARP`: the ORIGEN library interpolator will be removed in SCALE 7.0 in favor of inline interpolation methods used within ORIGEN and ORIGAMI. The following default changes will occur in SCALE 7.0. - `ORIGEN`'s CRAM solver will become the default instead of MATREX for `ORIGEN` and all other transport plus depletion sequences like `Polaris` and `TRITON`. - All `ORIGEN` libraries will be written in HDF5 format. Using SCALE ----------- SCALE sequences have been incrementally developed over several decades, with the primary goals of robustness, accuracy, and ease-of-use. One side effect of this evolution can be seen in our user interfaces: the text-based input that drives a calculation. There is no standard SCALE input. For example, TRITON, CSAS, and MAVRIC are similar in their style, which predates SCALE 6.2, when numerous new user interfaces were introduced. For example: - The Polaris sequence for lattice physics was modeled after the brevity and conciseness of CASMO and has a distinct syntax and output. - The ORIGEN code for general depletion and decay uses the SON syntax introduced in SCALE 6.2 as a significant upgrade from FIDO, but it keeps the same basic input structure and has a more general feel compared to Polaris. - The Sampler code for uncertainty propagation was created with a syntax originally intended to be the upgrade to the TRITON, CSAS, and MAVRIC style, but it was superseded by SON. - The shell sequence, which can perform a limited set of common file system operations across platforms. The SCALE input file is quite flexible in that it can contain numerous sequence inputs executed sequentially. For example, in the input below, we irradiate a milligram of iron in a beginning-of-life pressurized water reactor spectrum for one day and then decay for nine days. .. code-block:: scale =shell cp ${DATA}/arplibs/w17_e50.f33 f33 end =origen case{ lib{ file=f33 pos=1 } mat{ iso=[Fe=0.001] units=GRAMS } flux=[1e14 0] %neutrons/cm^2-s time=[ 1 10] %days } end The first `=shell` sequence copies a specific ORIGEN library from the SCALE data directory to the temporary working directory. ORIGEN can then find this file to load one-group cross sections for this test irradiation. Running SCALE from Fulcrum ~~~~~~~~~~~~~~~~~~~~~~~~~~ The most convenient way to run SCALE from a desktop is by launching Fulcrum. The Fulcrum executable is provided in the *bin* directory where SCALE was installed (e.g., :file:`C:\\SCALE-6.3.0\\bin\\Fulcrum.exe`). Fulcrum includes an online help document to assist users with its many features, and it includes links to the user manual and primers. Running SCALE from the Command Line ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Using the command line, SCALE can be executed using the *scalerte* command from the *bin* directory inside the SCALE installation (e.g., :file:`C:\\SCALE-6.3.0\\bin\\scalerte`). Your directory may differ based on the installation. Assuming the location of `scalerte` is known, a SCALE input can be run simply as :: scalerte -m my.inp with the `-m` option requesting SCALE to output status updates to the terminal. See :numref:`sec-scale.install` for details. User Guidance and Technical Assistance -------------------------------------- This SCALE manual serves as the primary reference for SCALE users. The fundamental theory and all code options are documented herein. Several SCALE primers are available to serve as step-by-step guides for new users performing common calculations using the GUIs. SCALE training courses are presented several weeks each year, during which users can interact directly with the software developers and expert users from ORNL. Additional technical information on SCALE can be found at http://scale.ornl.gov\ ---including training course schedules, a link to an online user forum, newsletters, benchmark reports, and downloads. Technical assistance is also provided via email at scalehelp@ornl.gov. Code Availability ----------------- The SCALE code system is packaged and distributed by the RSICC and is also distributed through the Organization for Economic Cooperation and Development (OECD) Nuclear Energy Agency (NEA) Data Bank in France and the Research Organization for Information Science and Technology (RIST) in Japan. History ------- The SCALE code system dates back to 1969, when ORNL began providing the transportation package certification staff at the US Atomic Energy Commission (AEC) with computational support in the use of the new KENO code. KENO was used to perform criticality safety assessments with the statistical Monte Carlo method. From 1969 to 1976, the AEC certification staff relied on ORNL personnel to assist them in the correct use of codes and data for criticality, shielding, and heat transfer analyses of transportation packages. However, the certification staff learned that occasional users had difficulty becoming proficient in performing the calculations often needed for an independent safety review. Thus, shortly after the certification staff was moved to the US Nuclear Regulatory Commission (NRC), the NRC proposed development of an easy-to-use analysis system that provided the technical capabilities of the individual modules with which they were familiar. With this proposal, the concept of SCALE as a comprehensive modeling and simulation suite for nuclear safety analysis and design was born. The NRC staff provided ORNL with some general development criteria for SCALE: (1) focus on applications related to nuclear fuel facilities and package designs, (2) use well-established computer codes and data libraries, (3) design an input format for the occasional or novice user, (4) prepare standard analysis sequences (control modules) to automate the use of multiple codes (functional modules) and data to perform a system analysis, and (5) provide complete documentation and public availability. With these criteria, the ORNL staff laid out the framework for the SCALE system and began development efforts. The initial version of SCALE (Version 0) was distributed in July 1980. Although the capabilities of the system continue to evolve, the philosophy established with the initial release still serves as the foundation of SCALE 6.3, more than 40 years later. In July 1980, the initial version of SCALE was made available to the Radiation Safety Information Computational Center (RSICC) at ORNL. This system was packaged and released by RSICC as CCC-288/SCALE 0. Subsequent additions and modifications resulted in the following releases: CCC-424/SCALE1 in 1981; CCC-450/SCALE 2 in 1983; CCC-466/SCALE 3 in 1985; CCC-545/SCALE 4.0 in 1990; SCALE 4.1 in 1992; SCALE 4.2 in 1994; SCALE 4.3 in 1995; SCALE 4.4 in 1998; SCALE 4.4a in 2000; CCC-725/SCALE 5 in 2004; CCC-732/SCALE 5.1 in 2006; CCC-750/SCALE 6.0 in 2009; CCC-785/SCALE 6.1 in 2011; CCC-834/SCALE 6.2 in 2016. Acknowledgements ---------------- Most team members are credited for their authorship of the sections in this manual that correspond to their work. A few individuals have been essential to the development and maintenance of SCALE but are not credited by authorship. These individuals include B. Taylor, J. Batson, M. Henley, S. Poarch, B. Bevard, L. Aloisi, D. Bowen, and R. Grove. We also acknowledge the support of Dr. A. Chambers and the DOE/NCSP and D. Algama, D. Barto, L. Kyriazidis, and H. Esmaili of the NRC. .. only:: html .. rubric:: References .. bibliography:: zSCALE.bib :cited: :labelprefix: Intro