Example Material.from_library() usage¶

Usage - finding available materials¶

Each of the materials available is stored in an internal dictionary that can be accessed using the AvailableMaterials() command.

import neutronics_material_maker as nmm
all_materials = nmm.AvailableMaterials()
print(all_materials.keys())

Usage - making materials from libraries¶

Here is an example that accesses a material from the internal collection called eurofer which has about 60 isotopes and a density of 7.78g/cm3.

import neutronics_material_maker as nmm

my_mat = nmm.Material.from_library(name='eurofer')

Once the object has been initiated the OpenMC or Serpent material card can be accessed.

my_mat.openmc_material
my_mat.serpent_material

To access MCNP material it is necessary to also provide an id.

my_mat = nmm.Material.from_library(name='eurofer', material_id=1)
my_mat.mcnp_material

To access the Fispact material it is necessary to also provide a volume.

my_mat = nmm.Material.from_library(name='eurofer', volume_in_cm3=10)
my_mat.fispact_material

To access the Shift material it is necessary to also provide a temperature and a material id

my_mat = nmm.Material.from_library(name='eurofer', temperature=293, material_id=1)
my_mat.shift_material

Usage - customising materials from libraries¶

Usage - hot pressurised Material()¶

For several materials within the collection the temperature and the pressure impacts the density of the material. The neutronics_material_maker adjusts the density to take temperature (in C or K) and the pressure into account when appropriate. Densities are calculated either by a material specific formula (for example FLiBe which has an temperature dependent equation for calculating the density https://github.com/fusion-energy/neutronics_material_maker/blob/a166ccebdb4949c987df75a404eaf8f63853e2c4/neutronics_material_maker/data/multiplier_and_breeder_materials.json#L32) or using CoolProps (for example coolants such as H2O).

import neutronics_material_maker as nmm

my_mat1 = nmm.Material.from_library('H2O', temperature=300, pressure=15e6)

my_mat1.openmc_material

Temperature must be provided in Kelvin.

import neutronics_material_maker as nmm

my_mat1 = nmm.Material.from_library('H2O', temperature=573.15, pressure=15e6)

my_mat1.openmc_material

The temperature is automatically sent to the openmc_material and serpent_material cards. However if this causes difficulties for you (perhaps due to not having cross sections at that temperature) this automatic propagate of temperature information can be disabled by setting the temperature_to_neutronics_code to False.

Usage - enriched Material()¶

For several materials within the collection the density is adjusted when the material is enriched. For breeder blankets in fusion it is common to enrich the lithium 6 content.

Lithium ceramics used in fusion breeder blankets often contain enriched lithium-6 content. This slight change in density is accounted for by the neutronics_material_maker.

import neutronics_material_maker as nmm

my_mat2 = nmm.Material.from_library('Li4SiO4', enrichment=60)

my_mat2.openmc_material

The default enrichment target for ‘Li4SiO4’ is Li6 but this can be changed if required.

import neutronics_material_maker as nmm

my_mat2 = nmm.Material.from_library('Li4SiO4', enrichment_target='Li7', enrichment=40)

my_mat2.openmc_material

Usage - adding extra lines to a material card¶

If you require additional lines at the end of the MCNP, Serpent, Fispact or Shift materia card then the additional_end_lines argument can be used. This will add specific line(s) to the end of a material card. Multiple lines can be added by creating a list with multiple entries.

In this example and additional line can be added to allow the S(α,β) treatment of water to be correctly modeled in MCNP. But this could also be used to add comments to the material card or other text at the end of the material card string.

import neutronics_material_maker as nmm

my_mat2 = nmm.Material.from_library(
    name='H2O',
    material_id=24,
    temperature=573.15,
    pressure=15e6,
    additional_end_lines={'mcnp': ['mt24 lwtr.01']}
)

print(my_mat2.mcnp_material)

The above code will return a MCNP material card string with the additional line ‘mt24 lwtr.01’ at the end. Note that spaces should also be set by the user.

c     H2O density 7.25553605e-01 g/cm3
M24   001001  6.66562840e-01
        001002  1.03826667e-04
        008016  3.32540200e-01
        008017  1.26333333e-04
        008018  6.66800000e-04
mt24 lwtr.01

It is also possible to specify this additional line in a JSON file and then read in the file and export the material. The additional end lines can also support different outputs for different codes and multiple lines being appended to the material card as demonstrated in this video on the feature.

Usage - importing your own library from a file¶

A correctly formated JSON file that contains materials defined in the same format as the exisiting materials can be added to the material library.

Assuming you have a JSON file saved as mat_lib.json with the following contents then this can be added to the material library in the the following manner.

{
    "my_secret_material": {
        "density": 1.0,
        "percent_type":"ao",
        "density_unit": "g/cm3",
        "elements": {
            "H": 0.2,
            "C": 0.8
        },
    }
}

This example file only contains one material but it could contain a list of several materials.

You can import this file into the package using AddMaterialFromFile().

import neutronics_material_maker as nmm
nmm.AddMaterialFromFile('mat_lib.json')
my_new_material = nmm.Material.from_library(name='my_secret_material')

Another option is to use AddMaterialFromDir() to import a directory of JSON files.

Usage - exporting a material to a JSON file¶

Materials can also be exported to a JSON file as demonstrated below. This JSON file can then be read back in if required using the AddMaterialFromDir or AddMaterialFromFile utility functions.

import neutronics_material_maker as nmm

my_mat1 = nmm.Material.from_library(name='eurofer', material_id=1)
my_mat2 = nmm.Material.from_library(name='Li4SiO4', material_id=1)

nmm.SaveMaterialsToFile(
    filename='my_materials.json',
    materials=[my_mat1, my_mat2],
    format='json',
)

The format can be changed to ‘mcnp’, ‘serpent’, ‘shift’ or ‘fispact’ to output a list of nmm.Materials in those formats.