burnupLassmannFBR

Description

The LassmannFBR burnup class in OFFBEAT is inspired by the work of Lassmann et al., "The radial distribution of plutonium in high burnup UO2 fuels" Journal of Nuclear Materials.

The class extends the functionality of the standard Lassmann burnup class to fast spectrum applications. In addition to the standard burnup class, this extension allows for:

• Solving for depletion of an extended number of nuclides (He4, U234, U235, U236, U237, U238, Np237, Np238, Np239, Pu238, Pu239, Pu240, Pu241, Pu242, Pu243, Am241, Am242, Am242m, Am243, Am244, Cm242, Cm243, Cm244 and Cm245);

• Accounting for He production through the mechanisms of alpha-decay, ternary fission and (n/alpha) reaction of O-16;

• Reading cross section data from lookup tables located in constant/XSdata;

The constant/XSdata dictionary allows the user to provide parametrized cross sectionf to be used for nuclide depletion. The type of parametrization depends on the reactorType selected by the user:

• If LWR is selected, fission and capture cross section are parametrized with respect the U-235 enrichment in UO2;

• If FBR is selected, fission and capture cross section are parametrized with respect the Pu wt% concentration in MOX;

Warning

The models requires the user to specify the reactorType keyword in the globalOptions dictionary of coinstant/solverDict. Currently, only LWR and FBR reactor types are supported.

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Options

Parameters in materials (for all fuel-type materials):

enrichment	For UO2 fuels, the enrichment of fissile material in fraction (i.e. 0.025 for a 2.5% enrichment).
isotopes	For MOX fuels, the isotopic composition of the fuel
densityFraction	The fraction of theoretical density of the fuel (e.g. 0.95).

Finally, the LassmannFBR burnup model requires the use of a neutronicsSolver (for instance, the diffusion solver) that calculates the neutron flux distribution in the fuel.

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Usage

Here is an example of the solverDict to be used for activating the LassmannFBR burnup model

globalOptions
{
    pinDirection            (0 0 1);
    reactorType             "FBR";
}

burnup LassmannFBR;
neutronicsSolver diffusion;

// ... 

materials
{
    fuel
    {
        material UPuO2;

        oxygenMetalRatio            1.97;

        isotopes
        {
            U
            {
                ratioOverMetal 0.80;
                weightFractions
                (
                    235 0.007
                    238 0.993
                );
            }
            Pu
            {
                ratioOverMetal 0.20;
                weightFractions 
                ( 
                    238 2.332e-2 
                    239 56.873e-2 
                    240 26.997e-2 
                    241 6.105e-2 
                    242 7.693e-2 
                );
            }
        }

    }

        // ... Rest of `fuel` dictionary
    }

    //.. Rest of materials

}