Running a cOMPoSe application module from the terminal

As is evident from the amount of information in the input file, running a cOMPoSe application is an involved process, with numerous steps and sub-processes. The basic signature is,

$ oscar5 MY_REACTOR.compose.my_module <cut or mode> [options [mode [options] ...]

where cut is any cut tag specified in the module and mode is any of the top level application modes listed in the following table:

Mode	Description
archive	Compress all input and output into a single archive file.
clean	Clears all input and output from the working directory (use with caution!)
visualization	Show a three dimensional representation of the model and the overlay homogenization mesh.
generator	Launches generator calculations for all the cuts.
update	Updates generator results for all the cuts.
library	Runs library mode for specified cuts.
equivalence	Runs equivalence mode for specified cuts.
deploy	Collects all homogenized mixtures in a single library, and exports the nodal configuration.
test	Runs defined 3D test cases.

All available modes can be viewed on the command line by passing the –help flag:

$ oscar5 MY_REACTOR.compose.my_module --help

Apart from the final deploy and test phases, most of the application interaction will be on a specific cut, which is covered next.

Homogenizing a two dimensional cut

For each cut, the application will:

1. Homogenize each channel (or node) in the radial mesh using the specified transport code,

2. Generate nodal parameters from the transport code output, and

3. Perform tests to check the performance of these parameters.

This is accomplished by a number of application sub modes, summarized in the following table:

Mode	Description
generator	Perform homogenization by running the transport code.
library	Create nodal parameters for all nodes (channels).
equivalence	Check if equivalence to the reference transport solution is preserved.
reconf	Check to what extend equivalence is broken when certain nodes are replaced with mixtures from different environments.

Generator mode

This mode controls homogenization of the current two dimensional cut. It is a standard rapyds application, and supports the full interface described here. The following lists the typical usage sequence for standard and axial reflector cuts.

First, start the homogenization procedure by launching (for example) on the remote host configured in host.cfg using 20 threads:

$ oscar5 MY_REACTOR.compose.my_module MY-CUT generator --config-file host.cfg execute --threads 20

You can monitor the (remote) running application by passing the –status flag to the execution mode:

$ oscar5 MY_REACTOR.compose.my_module MY-CUT generator --config-file host.cfg execute --status

Results can be viewed at any time using post mode:

$ oscar5 MY_REACTOR.compose.my_module MY-CUT generator --config-file host.cfg post --show

The –show flag will open a result viewer, which summarizes convergence errors in the homogenization application. The displayed error map shows a grid of the same size as the overlay homogenization_grid. Values in the nodes indicate the level of balance achieved in this node. These values should be close to one. Nodes are colored according to the maximum cross section relative error in that node.

Each segment in the mesh has two nested circles. The inner most circle denotes the relative error on boundary flux estimation, while the outer circle depicts errors on boundary current estimation. The outer circle is divided in two fragments, depicting in and outgoing current respectively.

The drop down list in the top right corner of the viewer allows one to switch between spectrum weighted and group specific errors. In the latter case, the balance number indicates within group balance, while in the former case, the number indicates total balance.

Note

You can run the post processor and view errors as soon as the target code has produced some output, that is, you do not need to wait for the run to finish. For long calculations running on a remote host, this is a useful mechanism to monitor convergence.

Burnup and state dependent homogenization

Since lattice cuts, have a lot more generator mode options, the command line interaction is covered in a separate section.

Library mode

Triggers the creation of HED files, POLX input and also runs POLX for each channel in the homogenization_grid. This mode accepts the following flags:

--correctbalance

Perform group wise balance correction for all nodes. This is an experimental feature, which ensures that balance is achieved in all energy groups. It is mostly applicable when Monte Carlo codes, which does not solve a local balance equation in each node, are used. In this case, the system will re-sample all parameters, from their current uncertainty distribution, with the constraint that balance is achieved in all nodes and energy groups.

Warning

The flag will perform constraint sampling of all the nodal parameters, which is a very large system for full core problems, requiring ample computer memory and time.

--errormap

Show a map of segments where the calculation of equivalence parameters failed. This usually occurs on boundaries were the equivalent nodal diffusion solution produced negative fluxes. Equivalence parameters on these boundaries are switched of.

--force

Force re-generation of all library files. If this flag is not specified, only out of date library files will be re-generated.

Typical usage:

$ oscar5 MY_REACTOR.compose.my_module MY-CUT library --errormap

Equivalence mode

Packs the homogenized mixtures of a specified two dimensional cut into an equivalent two dimensional MGRAC model. It also run MGRAC and compares results with the generator output. Since it will also run library mode if library files are not found, it accepts all the library mode flags.

--errormap

In this mode, the flag displays a basic interactive window with maps of errors relative to the generator results. The drop down box in the upper right corner can be used to switch between power and group flux errors.

Typical usage:

$ oscar5 MY_REACTOR.compose.my_module MY-CUT equivalence --errormap

Equivalence errors are usually caused by the following:

1. Lack of group wise balance in the generator results. This can be remedied by running the generator longer, or passing the --correctbalance flag.

2. Failure to produce equivalence parameters in library mode. This is the by far the biggest contributor to equivalence errors, and is not straight forward to remedy, as it usually indicates regions were diffusion theory fails. If errors occur in thin nodes, switching to a flat leakage model might help.

Attention

You can not run an equivalence calculation for axial reflector cuts.

Reconfiguration mode

Similar to equivalence mode, except that certain positions have reconfigured mixtures from other environments. Usage on the command line is as follows

$ oscar5 MY_REACTOR.compose.my_module <cut> reconf <case> [options]

where, <cut> should be replaced with the desired cut name, and <case> any one of the re-configured cases defined in the input module. The available options are:

--errormap

In this mode, the flag displays a basic interactive window with maps of errors relative to the generator results. The drop down box in the upper right corner can be used to switch between power and group flux errors.

Top level visualization

The top level visualization will show the entire model, and the nodalization mesh. It accepts the following command line arguments:

--cuts <list>

Comma separated list of cut names to include in the visualization. Defaults to ‘all’, so that all cut meshes will be displayed.

Recursive generator mode

Recursively launch all generator calculations for all the cuts defined in the script. This mode has the following signature:

$ oscar5 MY_REACTOR.compose.my_module generator [options]

where options are any standard application arguments or execution mode arguments.

Attention

This mode will currently not work with any burnup dependent lattice cuts defined in the input module.

Recursive update mode

Recursively updates all generator results for the cuts defined in the script. This mode has the following signature:

$ oscar5 MY_REACTOR.compose.my_module update [options]

where options are any standard application arguments or post mode arguments. This mode is particularly useful when a number of calculations were launched on a remote server.

Recursive library mode

Recursively run library mode for all specified cuts. Accepts the following arguments:

--cuts <list>

Comma separated list of cut names. Defaults to ‘all’.

--force

Flag indicating if existing libraries should be overwritten. If omitted, only non-existing or out of date libraries will be regenerated.

Recursive equivalence mode

Recursively run equivalence mode for all specified cuts. Accepts the following arguments:

--cuts <list>

Comma separated list of cut names. Defaults to ‘all’.

Deployment mode

Combine all the homogenized mixtures into a single library by running LYNX, and saves the nodal configuration to your model package.

This mode does not currently have any additional flags.

Test mode

Under construction!