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Nomenclature
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* - Symbols
- Definition
- Units
* - :math:`A, A_{\text{h}}`
- Axial segment length
- m
* - :math:`B`
- Burnup
- atom %
* - :math:`D`
- Grain size
- m
* - :math:`C_{\text{r}}`
- Calibration constant for metal fuel bubble radius
-
* - :math:`E`
- Modulus of elasticity
- Pa
* - :math:`E_{\text{c}}`
- Energy of the cladding
- J/kg
* - :math:`E_{\text{f}}`
- Modulus of Elasticity of the fuel
- Pa
* - :math:`F_{\text{as}}`
- Fraction of volume change occurring axially
-
* - :math:`F_{\text{f}}`
- Failure fraction
-
* - :math:`f`
- Mole fraction
-
* - :math:`G_{\text{f}}`
- Fission gas retained in fuel cell
- kg
* - :math:`G_{\text{r}}`
- Fission gas released from fuel cell
- kg
* - :math:`G_{\text{t}}`
- Total fission gas produced in fuel cell
- kg
* - :math:`g`
- Thermal jump distance
- m
* - :math:`F`
- Force
- N
* - :math:`H`
- Hardness of cladding
- Pa
* - :math:`H_{\text{sp}}`
- Height of sodium in the plenum
- m
* - :math:`h`
- Heat-transfer coefficient
- W m\ :sup:`-2`\ K\ :sup:`-1`
* - :math:`K`
- Bulk modulus
- Pa
* - :math:`k`
- Thermal conductivity
- W m\ :sup:`-1`\ K\ :sup:`-1`
* - :math:`M`
- Molecular weight, g mole, or Mass
- kg
* - :math:`M_{\text{s,j}}`
- Mass of sodium in fuel-cladding gap in axial segment j
- kg
* - :math:`M_{\text{s1}}`
- Mass of sodium loaded into the fuel pin
- kg
* - :math:`M_{\text{sp}}`
- Mass of sodium in the plenum region
- kg
* - :math:`M_{\text{st}}`
- Total mass of sodium in the fuel-cladding gap
- kg
* - :math:`n`
- Number of moles
-
* - :math:`P`
- Pressure
- Pa
* - :math:`P_{\text{cav}}`
- Molten cavity pressure
- Pa
* - :math:`P_{\text{ext}}`
- Coolant channel pressure
- Pa
* - :math:`P_{\text{fci}}`
- Fuel-Cladding interface pressure
- Pa
* - :math:`p`
- Porosity fraction
-
* - :math:`R`
- Universal gas constant
- J K\ :sup:`-1`\ g-mole\ :sup:`-1`
* - :math:`R_{\text{B}}`
- Fission gas bubble radius
- m
* - :math:`R_{\text{c}}`
- Fuel creep rate
- s\ :sup:`-1`
* - :math:`R_{\text{f}}`
- Fission gas release fraction
-
* - :math:`r`
- Radius
- m
* - :math:`r_{\text{cav}}`
- Radius of central molten cavity
- m
* - :math:`r_{\text{ci}}`
- Inner radius of the cladding
- m
* - :math:`r_{\text{co}}`
- Outer cladding radius
- m
* - :math:`r_{\text{cl}}`
- Outer boundary of SAS4A inner cladding cell
- m
* - :math:`r_{\text{c2}}`
- Outer boundary of SAS4A central cladding cell
- m
* - :math:`r_{\text{fo}}`
- Outer fuel radius
- m
* - :math:`r_{\text{p}}`
- Inner cladding radius in the plenum
- m
* - :math:`r_{\text{ci}}`
- Volumetric swelling fraction
-
* - :math:`r_{\text{co}}`
- Temperature
- K
* - :math:`r_{\text{ci}}`
- Average temperature
- K
* - :math:`r_{\text{cz}}`
- Temperature of cladding center
- K
* - :math:`r_{\text{fo}}`
- Inner cladding temperature
- K
* - :math:`r_{\text{p}}`
- Outer cladding temperature
- K
* - :math:`s_{\text{f}}`
- Temperature of PLUTO2/LEVITATE inner cladding node
- K
* - :math:`T`
- Temperature
- K
* - :math:`T_{\text{a}}`
- Average temperature
- K
* - :math:`T_{\text{cc}}`
- Temperature of cladding center
- K
* - :math:`T_{\text{ci}}`
- Inner cladding temperature
- K
* - :math:`T_{\text{co}}`
- Outer cladding temperature
- K
* - :math:`T_{\text{cl}}`
- Temperature of PLUTO2/LEVITATE inner cladding node
- K
* - :math:`T_{\text{eut}}`
- Eutectic temperature
- °C
* - :math:`T_{\text{f}}`
- Time to failure
- s
* - :math:`t`
- Time
- s
* - :math:`U`
- Velocity
- m s\ :sup:`-1`
* - :math:`U_{\text{ts}}`
- Ultimate tensile strength
- Pa
* - :math:`u`
- Radial displacement
- m
* - :math:`V`
- Volume
- m\ :sup:`3`
* - :math:`V_{\text{c}}`
- Volume of a cell
- m\ :sup:`3`
* - :math:`V_{\text{f}}`
- Volume of fission gas in closed porosity
- m\ :sup:`3`
* - :math:`V_{\text{r}}`
- Volume of fission gas moved from closed to open porosity
- m\ :sup:`3`
* - :math:`\Delta V_{\text{a}}`
- Axial volume change
- m\ :sup:`3`
* - :math:`\Delta V_{\text{exc}}`
- Volume of excess radial fuel swelling
- m\ :sup:`3`
* - :math:`\Delta V_{\text{r}}`
- Radial volume change
- m\ :sup:`3`
* - :math:`V_{\text{th}}`
- Theoretical volume of material in a cell
- m\ :sup:`3`
* - :math:`v`
- Circumferential displacement
- m
* - :math:`W`
- Weighting factor
-
* - :math:`z_{\text{o}}`
- Radially constant axial strain
-
* - :math:`Z`
- Axial elevation
- m
* - :math:`\alpha`
- Thermal-expansion coefficient
- K\ :sup:`-1`
* - :math:`\gamma`
- Surface tension
- N m\ :sup:`-1`
* - :math:`\Delta t`
- Time-step length
- s
* - :math:`\delta`
- Mean surface roughness
- m
* - :math:`\varepsilon`
- Strain or emissivity
-
* - :math:`\eta`
- Outer radius of solid fuel annulus
- m
* - :math:`\rho`
- Inner radius of solid fuel annulus or density
- m kg m\ :sup:`-3`
* - :math:`\rho s,j`
- Density of sodium in fuel-cladding gap in axial segment j
- kg m\ :sup:`-3`
* - :math:`\rho sp`
- Density of sodium in the plenum
- kg m\ :sup:`-3`
* - :math:`v`
- Poisson's ratio
-
* - :math:`\phi`
- Neutron flux
- n m\ :sup:`-2`\ s\ :sup:`-1`
* - :math:`\sigma`
- Stress, Pa, or Stefan-Boltzmann constant
- J s\ :sup:`-1`\ m\ :sup:`-2`\ k\ :sup:`-4`
* - :math:`Y`
- Time constant, s\ :sup:`-1`, or incubation parameter
- n/m\ :sup:`2`
* - :math:`\Sigma`
- Negative fractional density change in the cladding
-
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* - Superscripts
-
-
* - :math:`f`
- Force component
-
* - :math:`th`
- Thermal component
-
* - :math:`p`
- Plenum
-
* - :math:`v`
- Central fuel void
-
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* - Subscripts
-
-
* - :math:`r`
- Radial or reference
-
* - :math:`\theta`
- Circumferential
-
* - :math:`z`
- Axial
-
* - :math:`f`
- Force or fuel
-
* - :math:`th`
- Thermal
-
* - :math:`\rho`
- Inner radius of the solid fuel annulus
-
* - :math:`\eta`
- Outer radius of the solid fuel annulus
-
* - :math:`g`
- Plenum gas or fuel-cladding gap
-
* - :math:`FC`
- Fuel-cladding interface
-
* - :math:`c`
- Cladding
-
* - :math:`m`
- Maximum
-
* - :math:`k`
- Iteration counter
-
* - :math:`i`
- Time step or radial node
-
* - :math:`j`
- Axial node
-
* - :math:`B`
- Bubble
-
* - :math:`fg`
- Fission gas
-
* - :math:`s`
- Swelling
-
* - :math:`v`
- Central fuel void
-
* - :math:`p`
- Plenum or pore
-
* - :math:`He`
- Helium
-
* - :math:`T`
- Total
-
* - :math:`R`
- Reference
-
* - :math:`cav`
- Molten cavity
-
* - :math:`mc`
- Melting of cladding
-