Welcome New Bright-lite User!

Bright-lite is a collection of modules for the Cyclus Fuel Cycle Simulator that allow for medium fidelity reactor modeling. There are currently three modules in the Bright-lite suite.

• Bright-lite Reactor Facility
• Bright-lite Fuel Fabrication Facility
• Bright-lite Reprocessing Facility

Bright-lite Reactor Facility: A reactor modeling software that uses burnup, criticality, and transmutations matrix curves to determine input and output isotopic compositions. The reactor can also operate with user-defined fuel compositions, called the "forward" mode.

Bright-lite Fuel Fabrication Facility: A module that communicates directly with the Bright-lite Reactor Facility that allows for the reactor facility to access blending functions that will determine the isotopic composition of fuel that the reactor will be using in order to match a specific constraint.

Bright-lite Reprocessing Facility: A module that seperates user-defined isotopes out of a material that is sent to it. This currently requires an external text file to indicate which isotopes should be seperated with what efficiency into which streams. The structure of this text file can be seen here.

Bright-lite works in conjuction with the Cyclus Fuel Cycle Simulator.

Bright-lite is currently only being actively supported for Ubuntu.

Installation

To use Bright-lite first you need to install it. Currently Bright-lite has the following dependencies.

• Cyclus Fuel Cycle Simulator

The following dependencies will be required in the future

• Eigen

To install Bright-lite please follow these instructions.

1. Clone the Bright-lite repository from github.

   git clone repository url

2. Change directory into the Bright-lite directory using the following command.

   cd Bright-lite

3. Use the following command inside the Bright-lite directory.

   python install.py

This will add the Bright-lite module to the cyclus environment, and allow you to use Bright-lite in Cyclus simulations.

Using Bright-lite

Bright-lite reactor requires at least 6 inputs from the users to operate fully. While there are several other inputs associated with the module, all of these other inputs come with a default value.

The six required inputs are

• in_commods: This field is a one or more that indicates the possible sources of fuel for the reactor. The values in this field should be commodities that exist inside of the simulation. In order to use Bright-lite in forward mode, set the first source to the steady-state (non-startup) fuel supplier. For forward mode the startup fuels can be set with additional sources.
• out_commod: This field should be filled out with the cyclus commodity that will connect the reactor facility to the facility that will be directly handling the waste.
• libraries: This is a one or more field that indicates the Bright-lite library database the reactor will be using. Note: Adding additionally library databases to this list will enable the library interpolation capabilities in Bright-lite but also requires that the user input parameters and values to be interpolated upon. The interpolation feature is intended for advanced users.
• target_burnup: This field indicates the target burnup for the reactor. If this is set to 0, the reactor will operate in forward mode. If this value is not set to zero the Bright-lite reactor must be connected to a Bright-lite fuel fabrication facility.
• core_mass: This field indicates the total mass of fuel inside of the core. This mass does not include structural components, it is only the mass of fuel to be burned.
• generated_power: This indicates the total thermal generating power of the core. The electrical generated_power will be this value times the effiency of the reactor (a input set to default at 33% but is user adjustable).

Operational Modes

Bright-lite has two operational modes. The mode is indicated using inputs to the Bright-lite reactor module. Forward mode is chosen by setting the reactor target_burnup mode to be equal to 0. Blending mode requires the target_burnup field to be a non negative value. Additionally, blending mode requires the Bright-lite ReactorFacility to be connected to a Bright-lite FuelfabFacility.

Forward Mode

In forward mode Bright-lite accepts a fuel composition and burns it. It does this by advancing the fluence of each batch in the core until the target is met (such as k = 1).

Currently forward mode works only with criticality and burnup targets.

Blending Mode

As stated above using the blending function in Bright-lite requires connecting a Bright-lite ReactorFacility to a Bright-lite FuelfabFacility. The in_commods field of the Bright-lite reactor should include all of the fuel fabrication facilities that the reactor can be connected to.

Currently there are two blending modes available in Bright-lite. These modes are described by a target-constraint pairing. The two available pairs currently are:

1. Burnup - Criticality: The blender will create a fuel that meets a target burnup when criticality is equal to the given constraint. This set of constraints only requires a non negative number to be entered into the target_burnup field.

2) Burnup - Conversion Ratio: The blender will create a fuel that meets a target burnup when conversion ratio is equal to the given constraint. This is achieved by setting the CR_target input field of the reactor to be equal to a number greater than 0 (note that there is no upper bound limit in the code for this this but physically it should not exceed 2). Additionally the target_burnup field must be a non negative value for this to work.

Running Example Cases

There are several example cases provided with Bright-lite. The single reactor example cases are:

• LWR, 3 batch, 33 MWd/kg burnup, 3.1 % U-235 fuel (forward mode)
• LWR, 4 batch, 42 MWd/kg burnup, 3.6 % U-235 fuel (forward mode)
• LWR, 4 batch, 51 MWd/kg burnup, 4.3 % U-235 fuel (forward mode)
• LWR, 4 batch, 45 MWd/kg target burnup (blending mode)
• MOX, 5 batch, 50 MWd/kg burnup (forward mode)
• MOX, 5 batch, 50 MWd/kg target burnup (blending mode)
• Fast reactor, 6 batch, 180 MWd/kg burnup (forward mode)

The files can be found in the Bright-lite/examples/ folder. Run the following command to run the 42 MWd/kg burnup example case.

cyclus Bright-lite/examples/LWR42forward.xml

Library Interpolation

The libraries used in Bright-lite are often associated with several parameters. For example an LWR reactor library might have parameters for burnup, and enrichment. If as a user, you require a different value for these parameters there are two possible methods for obtaining it First, a new library can be generated externally from Bright-lite using tools available (XSGEN for example). It is also possible to create a dynamic library that matches your desired parameters using Bright-lite's built in library interpolation tool.

This tool is used using two key components in the Bright-lite input schema.

libraries - To enable library interpolation here simple add more than one library to the field. This is done simply by adding another val to the input field. That is...:

<val>extLWR</val>

represents a reactor library using just the extLWR library. However by adding another library:

<val>extLWR</val>
<val>lowLWR</val>

Bright-lite will make a new library based on the interpolation pairs and the values inside of these two libraries.

interpolation_pairs Once two or more libraries have been selected at least one interpolation pair will need to be added. An interpolation pair is a <"Parameter", Value> pair. The parameter represents a common parameter shared by the libraries, and the value is the target value for the new dynamic library in that parameter.

For example, there may be two LWR libraries that fit into an LWR library suite.

• Reactor 1

• Burnup: 50 MWd/kgIHM
• Enrichment: 5% U235

• Reactor 2

• Burnup: 30 MWd/kgIHM
• Enrichment: 3.3% U235

If a new library with the following parameters is desired

• Dynamic Reactor

• Burnup: 40 MWd/kgIHM
• Enrichment: 4% U235

The following xml should be added to the reactor archetype.

<libraries>
 <val>Reactor 1</val>
 <val>Reactor 2</val>
</libraries>
<interpolation_pairs>
 <key>BURNUP</key>
 <val>40</val>
 <key>ENRICHMENT</key>
 <val>4</val>
</interpolation_pairs>

Available Libraries

Recommended Libraries

• lowLWR - A standard PWR library.

• Enrichment: 2.2 %U235
• Burnup: 20 MWd/kgIHM
• PNL: 0.903
• Batches: 3

• standLWR

• Enrichment: 3.3 %U235
• Burnup: 33 MWd/kgIHM
• PNL:0.911
• Batches: 3

• extLWR

• Enrichment: 5% U235
• Burnup: 50 MWd/kgIHM
• PNL: 0.883
• Batches: 3

• BWRMOX

• Burnup:
• PNL:
• Batches:

• PWRMOX

• Burnup:
• PNL:
• Batches:

• DUPIC

• Burnup:
• PNL:
• Batches:

• FR25

• Burnup:
• Conversion Ratio: 0.25
• PNL:
• Batches:

• FR25MOX

• Burnup:
• Conversion Ratio: 0.25:
• PNL:
• Batches:

• FR50

• Burnup:
• Conversion Ratio: 0.5:
• PNL:
• Batches:

• MOXMA

• Burnup:
• PNL:
• Batches:

Additional Libraries

• E5_50

• Enrichment
• Burnup
• PNL
• Batches

• E5_60

• Enrichment
• Burnup
• PNL
• Batches

• E7_100

• Enrichment
• Burnup
• PNL
• Batches

• E9_100

• Enrichment
• Burnup
• PNL
• Batches

Format of Reprocessing Plant Text File

BEGIN
isotope1n fraction1n
isotope2n fraction2n
...
isotopeN fractionN
END
BEGIN
isotope1k fraction1k
isotope2k fraction2k
...
isotopeK fractionK
END

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