MATERIALS / PROPERTIES & DEFINITIONS
Materials¶
Material properties and OpenMC definitions for the GFMR reference specification.
FUNaK fuel¶
Fuel salt. Reference 1.
| Property | Specification |
|---|---|
| Composition | 26.4 UF4 – 24.7 KF – 48.9 NaF mol% |
| Reference enrichment | 2.12% (OpenMC uranium enrichment parameter) |
| Density | ρ = 4.808 − 0.00113 T g/cm3, T in °C |
| Viscosity | η = 736.58 exp(−0.006 T) mPa s, T in °C |
| Heat capacity | Cp = 900 J kg−1 K−1 |
| Thermal conductivity | Awaiting specification |
OpenMC definition
Listing 1 · FUNaK fuel
fuel = openmc.Material(name='fuel')
fuel.add_element('Na', 0.1751432664756447, 'ao')
fuel.add_element('K', 0.08846704871060172, 'ao')
fuel.add_element('F', 0.6418338108882521, 'ao')
fuel.add_element('U', 0.094555874, 'ao', enrichment=enrichment)
density_fuel = 4.808 - 0.00113 * (temperature_fuel_C)
fuel.set_density('g/cm3', density_fuel)
fuel.temperature = temperature_fuel_K
Graphite¶
Moderator / reflector. References 2, 3.
| Property | Specification |
|---|---|
| Composition | Carbon 99.9999 atom%; boron 0.0001 atom% (1 atomic ppm) |
| Density | 1.7 g/cm3 |
| Specific heat capacity | Awaiting specification |
| Thermal conductivity | K = 25 W m−1 K−1 (constant in the current specification) |
| Thermal conductivity versus dpa | Awaiting specification of K(T, dpa), graphite grade, and irradiation conditions |
Here, dpa means displacements per atom. The constant conductivity above does not define an irradiation-dependent correlation.
OpenMC definition
Listing 2 · Graphite moderator
moderator = openmc.Material(name='graphite')
moderator.add_element('C', 0.999999)
moderator.add_element('B', 0.000001)
moderator.set_density('g/cm3', 1.7)
moderator.add_s_alpha_beta('c_Graphite')
moderator.temperature = t_graphite_K
Hafnium¶
Absorber. Reference 4.
| Property | Specification |
|---|---|
| Composition | Pure hafnium, natural isotopic composition |
| Density | 13.3 g/cm3 |
| Specific heat capacity | Awaiting specification |
| Thermal conductivity | Awaiting specification |
OpenMC definition
Listing 3 · Hafnium absorber
absorber = openmc.Material(name='control_rod')
absorber.add_element('Hf', 1.0, 'ao')
absorber.set_density('g/cm3', 13.3)
absorber.temperature = temperature_fuel_K
Hastelloy N¶
Guide tube. Reference 5.
| Property | Specification |
|---|---|
| Composition | Ni 71%, Cr 7%, Mo 16%, Fe 4%, Si 1%, Mn 0.8%, V 0.2% by mass |
| Density | 8.86 g/cm3 |
| Specific heat capacity | Awaiting specification |
| Thermal conductivity | Awaiting specification |
OpenMC definition
Listing 4 · Hastelloy N guide tube
guide_tube_material.add_element('Ni', 71, percent_type='wo')
guide_tube_material.add_element('Cr', 7, percent_type='wo')
guide_tube_material.add_element('Mo', 16, percent_type='wo')
guide_tube_material.add_element('Fe', 4, percent_type='wo')
guide_tube_material.add_element('Si', 1, percent_type='wo')
guide_tube_material.add_element('Mn', 0.8, percent_type='wo')
guide_tube_material.add_element('V', 0.2, percent_type='wo')
guide_tube_material.set_density('g/cm3', 8.86)
guide_tube_material.temperature = temperature_fuel_K
Helium¶
Gap. Reference 6.
| Property | Specification |
|---|---|
| Composition | Pure helium, natural isotopic composition |
| Density | 0.0001785 g/cm3 (fixed in the OpenMC definition) |
| Specific heat capacity | Awaiting specification |
| Thermal conductivity | Awaiting specification |
OpenMC definition
Listing 5 · Helium gap
helium = openmc.Material(name='helium')
helium.add_element('He', 1.0)
helium.set_density('g/cm3', 0.0001785)
helium.temperature = temperature_fuel_K
Entries marked “Awaiting specification” are not yet defined in the GFMR model. Temperature-dependent properties and the graphite irradiation correlation will be added when those model inputs are available.