.. _ch4nom:
Nomenclature
================================================================================
.. list-table::
:header-rows: 1
:align: center
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* - Symbol
- Description
- Units
* - :math:`A`
- Coefficient in EBR-II bowing reactivity.
- $
* - :math:`A_{\text{cr}}`
- Control rod driveline heat transfer area.
- m\ :sup:`2`
* - :math:`A_{\text{e}}`
- Nominal cross-sectional area of cladding.
- m\ :sup:`2`
* - :math:`A_{\text{f}}`
- Nominal cross-sectional area of fuel.
- m\ :sup:`2`
* - :math:`a`
- Above-core load pad elevation.
- m
* - :math:`a_{\text{cr}}`
- Coefficient in control rod driveline reactivity feedback.
- $/m
* - :math:`B`
- Coefficient in EBR-II bowing reactivity.
- $
* - :math:`b_{\text{cr}}`
- Coefficient in control rod driveline reactivity feedback.
- $/m\ :sup:`2`
* - :math:`C_{\text{cr}}`
- Control rod driveline specific heat.
- J/kg-K
* - :math:`C_{\text{i}}`
- Delayed neutron precursor group :math:`i` population.
-
* - :math:`C_{\text{rc}}`
- Coefficient in simple radial core expansion reactivity feedback.
- $/K
* - :math:`D`
- Hex can flat-to-flat dimension.
- m
* - :math:`D_{\text{z}}`
- Nominal axial node height in simple axial expansion reactivity feedback model.
- m
* - :math:`E`
- Modulus of elasticity.
- N/m\ :sup:`2`
* - :math:`F_{\text{cr}}`
- Temperature multiplier in EBR-II control rod bank expansion model.
-
* - :math:`F_{\text{LowBU}}`
- Fraction of fuel elements with burnup less than 2.9% in EBR-II.
-
* - :math:`f_{\text{e}}`
- Cladding mesh height expansion factor.
-
* - :math:`f_{\text{f}}`
- Fuel mesh height expansion factor.
-
* - :math:`f_{\text{i}}`
- Channel flag in simple radial expansion reactivity model.
-
* - :math:`H`
- Fuel height in EBR-II.
- m
* - :math:`h_{\text{cr}}`
- Coolant to control rod driveline heat transfer coefficient.
- W/m\ :sup:`2`-k
* - :math:`H_{\text{n}}`
- Normalized decay heat energy fraction for group :math:`n`.
-
* - :math:`I`
- Moment of inertia of beam cross-sectional area.
- m\ :sup:`4`
* - :math:`k`
- Reactor effective multiplication constant.
-
* - :math:`\delta k`
- Reactivity, or change in the effective reactor multiplication constant.
-
* - :math:`\delta k_{\text{cl}}`
- Cladding relocation reactivity.
-
* - :math:`\delta k_{\text{cr}}`
- Control rod drive expansion reactivity.
-
* - :math:`\delta k_{\text{cs}}`
- Control system reactivity.
-
* - :math:`\delta k_{\text{D}}`
- Fuel Doppler reactivity.
-
* - :math:`\delta k_{\text{d}}`
- Fuel and cladding axial expansion reactivity.
-
* - :math:`\delta k_{\text{fu}}`
- Fuel relocation reactivity.
-
* - :math:`\delta k_{\text{Na}}`
- Coolant density or voiding reactivity.
-
* - :math:`\delta k_{\text{p}}`
- User-programmed reactivity.
-
* - :math:`\delta k_{\text{re}}`
- Core radial expansion reactivity.
-
* - :math:`L`
- Elevation of top load pad.
- m
* - :math:`L_{\text{cr}}`
- Control rod driveline length.
- m
* - :math:`L_{\text{k}}`
- Reactor vessel wall length represented by compressible volume :math:`k` or element :math:`k`.
- m
* - :math:`M`
- Bending moment.
- N-m
* - :math:`M_{\text{cr}}`
- Control rod driveline mass.
- kg
* - :math:`M_{\text{GR}}`
- Applied moment at grid plate.
- N-m
* - :math:`M_{1}`
- Thermally induced bending moment in the core region.
- N-m
* - :math:`M_{2}`
- Thermally induced bending moment above the core region.
- N-m
* - :math:`m_{\text{ij}}`
- Fuel or cladding mass at node :math:`j` in channel :math:`i` in fuel and cladding relocation reactivity.
- kg
* - :math:`N`
- Fuel, sodium, or steel atom density in EBR-II reactivity model.
- atm/m\ :sup:`3`
* - :math:`N_{\text{c}}`
- Number of channels.
-
* - :math:`N_{\text{s}}`
- Number of subassemblies per channel.
-
* - :math:`P`
- Radial force at the above core load pad.
- N
* - :math:`P_{\text{t}}^{k}`
- Normalized power in interval :math:`k` of irradiation history for decay heat precursor initial condition.
-
* - :math:`Q`
- Space and time dependent nodal power.
- W
* - :math:`Q_{\text{t}}`
- Total recoverable energy per fission
- MeV
* - :math:`R_{\text{e}}`
- Cladding nodal reactivity worth in simple axial expansion reactivity model.
- kg\ :sup:`-1`
* - :math:`R_{\text{f}}`
- Fuel nodal reactivity worth in simple axial expansion reactivity model.
- kg\ :sup:`-1`
* - :math:`R_{\text{i}}`
- Radial fuel reactivity worth shape factor in EBR-II reactivity model.
-
* - :math:`R_{1}`
- Minimum core radius at above-core load pad in detailed radial expansion model.
- m
* - :math:`R_{2}`
- Minimum core radius at top load pad in detailed radial expansion model.
- m
* - :math:`R_{3}`
- Maximum core radius at restraint ring in detailed radial expansion.
- m
* - :math:`\overrightarrow{r}`
- Reactor spatial position vector.
-
* - :math:`S`
- Space-dependent steady-state nodal power.
- W
* - :math:`S_{\text{GR}}`
- Subassembly slope with respect to vertical at the grid plate.
- m/m
* - :math:`S_{\text{GRMAX}}`
- Maximum subassembly slope with respect to vertical at the grid plate.
- m/m
* - :math:`T`
- Temperature.
- K
* - :math:`\overline{T}`
- Average temperature.
- K
* - :math:`\Delta T`
- Hexcan flat-to-flat temperature difference.
- K
* - :math:`T_{\text{by}}`
- Bypass region temperature.
- K
* - :math:`T_{\text{ch}}`
- Reflector steel temperature.
- K
* - :math:`T_{\text{cr}}`
- Control rod driveline temperature.
- K
* - :math:`T_{\text{cv}1}`
- Inlet plenum coolant temperature.
- K
* - :math:`T_{\text{cv}2}`
- Outlet plenum coolant temperature.
- K
* - :math:`T_{\text{e}}`
- Cladding temperature.
- K
* - :math:`T_{\text{f}}`
- Fuel temperature.
- K
* - :math:`{\overline{T}}_{\text{f}}`
- Average fuel temperature.
- K
* - :math:`\Delta T_{f}`
- Fuel temperature change.
- K
* - :math:`\Delta{\overline{T}}_{\text{favg}}`
- Average fuel temperature change.
- K
* - :math:`{\overline{T}}_{\text{floc}}`
- Average fuel temperature for a channel.
- K
* - :math:`T_{\text{i}}`
- Plenum coolant temperature.
- K
* - :math:`T_{\text{in}}`
- Coolant inlet temperature.
- K
* - :math:`\Delta T_{\text{in}}`
- Coolant inlet temperature change.
- K
* - :math:`T_{\text{j}}`
- Reflector coolant temperature.
- K
* - :math:`{\overline{T}}_{\text{k}}`
- Average vessel wall temperature in :math:`k`-th compressible volume or element.
- K
* - :math:`{\overline{T}}_{\text{lr}}`
- Average coolant temperature in lower reflector.
- K
* - :math:`T_{\text{mm}}`
- Mixed mean coolant core outlet temperature.
- K
* - :math:`{\overline{T}}_{\text{Na}}`
- Average coolant temperature.
- K
* - :math:`{\overline{T}}_{\text{rr}}`
- Average radial reflector coolant temperature.
- K
* - :math:`T_{\text{SLP}}`
- Space and time dependent structure temperature.
- K
* - :math:`{\overline{T}}_{\text{SLP}}`
- Space-average, time dependent structure temperature.
- K
* - :math:`{\Delta\overline{T}}_{\text{SLP}}`
- Change in space-averaged structure temperature.
- K
* - :math:`\Delta T_{\text{ss}}`
- Cladding temperature change.
- K
* - :math:`{\overline{T}}_{\text{ss}}`
- Average cladding temperature.
- K
* - :math:`T_{\text{ui}}`
- Coolant temperature in the upper internal structure region.
- K
* - :math:`{\overline{T}}_{\text{ur}}`
- Average coolant temperature in the upper reflector.
- K
* - :math:`t`
- Time.
- s
* - :math:`\Delta t`
- Change in time.
- s
* - :math:`V_{\text{by}}`
- Bypass region volume.
- m\ :sup:`3`
* - :math:`V_{\text{c}}h`
- Channel steel volume.
- m\ :sup:`3`
* - :math:`V_{\text{cv}1}`
- Inlet plenum volume.
- m\ :sup:`3`
* - :math:`V_{\text{cv}2}`
- Outlet plenum volume.
- m\ :sup:`3`
* - :math:`V_{\text{f}}`
- Fuel volume.
- m\ :sup:`3`
* - :math:`V_{\text{GR}}`
- Radial reaction at the grid plate.
-
* - :math:`V_{\text{i}}`
- Plenum coolant volume.
- m\ :sup:`3`
* - :math:`V_{\text{i}}`
- Channel volume.
- m\ :sup:`3`
* - :math:`V_{\text{j}}`
- Reflector coolant volume.
- m\ :sup:`3`
* - :math:`V_{\text{k}}`
- Nodal volume at :math:`k` in channel.
- m\ :sup:`3`
* - :math:`V_{\text{Na}}`
- Sodium volume in fuel/cladding gap.
- m\ :sup:`3`
* - :math:`V_{\text{ss}}`
- Cladding volume.
- m\ :sup:`3`
* - :math:`V_{\text{ui}}`
- Coolant volume in upper internal structure.
- m\ :sup:`3`
* - :math:`w_{\text{c}}`
- Core outlet flow rate.
- kg/s
* - :math:`w_{\text{k}}`
- Core volume weighting for decay heat curve :math:`k`.
-
* - :math:`\text{XAC}`
- Distance from subassembly nozzle support to above core load pad.
- m
* - :math:`\text{XMC}`
- Distance from subassembly nozzle support to core midplane.
- m
* - :math:`x`
- Axial elevation in detailed radial core expansion model.
- m
* - :math:`x_{1}`
- Elevation of lower axial blanket/lower reflector interface.
- m
* - :math:`x_{\text{i}}`
- Fraction of total fission power from isotope :math:`i`.
-
* - :math:`Y`
- Fraction of full power temperature rise.
-
* - :math:`Y_{\text{e}}`
- Cladding Young's modulus.
-
* - :math:`Y_{\text{f}}`
- Fuel Young's modulus.
-
* - :math:`Y_{\text{ss}}`
- Cladding Young's modulus.
-
* - :math:`y`
- Radial displacement with respect to the core radius at the grid plate.
- m
* - :math:`Z_{\text{k}}`
- Axial fuel reactivity worth shape.
-
* - :math:`\Delta z_{\text{cr}}`
- Control rod driveline expansion.
- m
* - :math:`z_{0}`
- Unexpanded axial mesh elevation.
- m
* - :math:`\Delta z_{\text{n}}`
- Net control rod movement.
- m
* - :math:`z_{\text{ne}}`
- Expanded cladding mesh elevation.
- m
* - :math:`z_{\text{nf}}`
- Expanded fuel mesh elevation.
- m
* - :math:`\Delta z_{\text{v}}`
- Reactor vessel expansion.
- m
* - :math:`\alpha`
- Subassembly hex can thermal expansion coefficient.
- 1/K
* - :math:`\alpha_{\text{cr}}`
- Control rod driveline thermal expansion coefficients.
- 1/K
* - :math:`\alpha_{\text{D}}`
- Local fuel Doppler coefficient.
-
* - :math:`\alpha_{\text{e}}`
- Cladding thermal expansion coefficient.
- 1/K
* - :math:`\alpha_{\text{f}}`
- Fuel thermal expansion coefficient.
- 1/K
* - :math:`\alpha_{\text{jI}}`
- Average coolant void fraction in axial node :math:`j` of channel :math:`I`.
-
* - :math:`\alpha_{\text{k}}`
- Reactor vessel thermal expansion coefficient.
- 1/K
* - :math:`\alpha_{\text{Lf}}`
- Fuel thermal expansion coefficient.
- 1/K
* - :math:`\alpha_{\text{Lss}}`
- Cladding thermal expansion coefficient.
- 1/K
* - :math:`\alpha_{\text{VNa}}`
- Sodium volumetric thermal expansion coefficient.
- 1/K
* - :math:`\alpha_{\text{n}}`
- Contribution of group :math:`n` to immediate decay heat from a single fission event
- MeV
* - :math:`\beta`
- Total effective delayed-neutron fraction
-
* - :math:`\beta_{\text{n}}`
- Effective decay-heat power fraction for group :math:`n`.
-
* - :math:`\beta_{\text{i}}`
- Effective delayed-neutron precursor group :math:`i` fraction.
-
* - :math:`\delta_{\text{e}}`
- Cladding axial expansion.
- m
* - :math:`\delta_{\text{f}}`
- Fuel axial expansion.
- m
* - :math:`\epsilon_{\text{d}}`
- Sodium density multiplier.
-
* - :math:`\epsilon_{\text{e}}`
- Cladding fractional thermal expansion.
-
* - :math:`\epsilon_{\text{ex}}`
- Effective axial expansion multiplier.
-
* - :math:`\epsilon_{\text{f}}`
- Fuel fractional thermal expansion.
-
* - :math:`\zeta`
- EBR-II reactivity parameter.
- $
* - :math:`\zeta_{\text{bw}}`
- EBR-II bowing reactivity parameter.
- $
* - :math:`\zeta_{\text{c}}`
- EBR-II coolant reactivity parameter.
- $
* - :math:`\zeta_{\text{cr}}`
- EBR-II control rod driveline reactivity parameter.
- $
* - :math:`\zeta_{\text{fa}}`
- EBR-II axial fuel expansion reactivity parameter.
- $
* - :math:`\zeta_{\text{fr}}`
- EBR-II radial fuel expansion reactivity parameter.
- $
* - :math:`\zeta_{\text{lr}}`
- EBR-II lower reflector reactivity parameter.
- $
* - :math:`\zeta_{\text{rr}}`
- EBR-II radial reflector reactivity parameter.
- $
* - :math:`\zeta_{\text{ssa}}`
- EBR-II axial cladding expansion reactivity parameter.
- $
* - :math:`\zeta_{\text{ssr}}`
- EBR-II radial cladding expansion reactivity parameter.
- $
* - :math:`\zeta_{\text{ur}}`
- EBR-II upper reflector reactivity parameter.
- $
* - :math:`\Lambda`
- Prompt neutron lifetime.
- s
* - :math:`\lambda_{\text{n}}`
- Decay heat group effective decay constant for group :math:`n`.
- 1/s
* - :math:`\lambda_{\text{i}}`
- Delayed neutron precursor group :math:`i` decay constant.
- 1/s
* - :math:`\rho_{\text{c}}`
- Local coolant void reactivity worth.
- g\ :sup:`-1`
* - :math:`\Delta\rho_{\text{e}}`
- Cladding axial expansion reactivity.
-
* - :math:`\Delta\rho_{\text{f}}`
- Fuel axial expansion reactivity.
-
* - :math:`\rho_{\text{u}}`
- Sodium density in outlet plenum.
- kg/m\ :sup:`3`
* - :math:`\phi`
- Normalized fission power amplitude.
-
* - :math:`\phi_{1}`
- First order coefficient in normalized fission power amplitude expansion.
- s\ :sup:`-1`
* - :math:`\phi_{2}`
- Second order coefficient in normalized fission power amplitude expansion.
- s\ :sup:`-2`
* - :math:`\psi_{\text{f}}`
- Normalized fission power.
-
* - :math:`\psi_{\text{h}}`
- Normalized decay heat power.
-
* - :math:`\psi_{\text{t}}`
- Normalized total power.
-