================================================================================ Nomenclature ================================================================================ .. list-table:: :header-rows: 1 :align: center :widths: 1,3,1 * - Symbols - Description - Units * - *Superscripts* - - * - l - Linear - * - n - Time step n - * - ' - Prime always indicates that a quantity refers to a unit of generalized smear volume - * - *Subscripts* - - * - ac - Acoustic - * - bk - Lower boundary of node K - * - ca - Cavity - * - cl - Cladding - * - fica - Free fission gas in molten pin cavity - * - fr - Friction - * - fsca - Dissolved fission gas in the molten pin cavity - * - fuca - Mobile fuel in the molten pin cavity - * - fufi - Fuel and fission gas - * - fvca - Fuel vapor in the molten pin cavity - * - i - Axial coolant channel index, specific enthalpy - * - if - Interface - * - K - Axial pin or cavity index - * - liq - Liquidus - * - me - Melting, melt-in - * - min - Minimum - * - max - Maximum - * - Na - Sodium - * - Nl - Liquid sodium - * - Nv - Sodium vapor - * - pin,pi - Pin - * - rl - Dissolved fission-gas release - * - S' - Sink or source per unit of generalized smear volume - * - sol - Solidus - * - un - Uncompressed - * - vg - Vapor and gas - * - vi - Viscous - * - z - Axial location z - * - *Greek* - - * - α - Void fraction - * - β - Delayed neutron fraction - * - γ - C\ :sub:`p`/C:sub:`v` - * - δ - Partial derivative - * - Δ - Derivative in finite differences - * - κ - Compressibility - 1/Pa * - Ï€ - Circumference of a circle divided by its diameter - * - Ï - Theoretical density - kg/m\ :sup:`3` * - Ï' - Generalized linear density - kg/m\ :sup:`3` * - σ - Surface tension - J/m\ :sup:`2` * - θ - Generalized volume fraction - * - *Regular* - - * - A - Cross section area - m\ :sup:`2` * - A' - Interaction or surface area per unit of generalized smear volume - 1/m * - AXMX - Input, reference cross section area; recommended input value is subassembly cross section area - m\ :sup:`2` * - BFR - Input, exponent of liquid friction coefficient - * - BFRV - Input, exponent of vapor friction coefficient - * - C - Specific heat - J(kg·K) * - CDFU - Input, fuel conductivity - J(m·s·K) * - CDNL - Input, liquid sodium conductivity - J(m·s·K) * - CDVG - Input, conductivity of sodium vapor - J(m·s·K) * - CFCOFV - Input, fuel vapor condensation coefficient - J(m\ :sup:`2`\ ·s·K) * - CIA3 - Input, constant in the Deissler heat-transfer-correlation - * - CIFRFU - Input part of the fuel friction calculation - * - CIREFU - Input, Reynolds number above which fully turbulent fuel flow is assumed for friction calculation - * - CIRTFS - Input, controls dissolved gas release - 1/s * - CMFU - Input, liquid fuel compressibility - 1/Pa * - CPFU - Input, fuel heat capacity - J/(kg·K) * - D - Diameter, hydraulic diameter - m * - e - Internal energy - J/kg * - EGBBLY - Input, internal fuel energy below which fuel freezing begins - J/kg * - EGFULQ - Input, internal fuel energy at the liquidus - J/kg * - EGFUSO - Input, internal fuel energy at the solidus - J/kg * - EPCH - Input, controls use of advanced pressure in in-pin calculation - * - F - Friction factor - * - FNFUAN - Input, controls when annular fuel flow in molten pin cavity is assumed - * - FNMECA - Fraction of node width of radial node on cavity boundaries which melts in per PINACLE time step - * - FNMELT - Input, controls location of cavity boundary - * - FNPOE - Relative power level - * - FUELMS - Initial fuel mass in radial fuel-pin node - kg * - FUMASS - Initial total fuel mass in an axial fuel node - kg * - FUMS - Current fuel mass in the radial fuel pin node on the cavity boundary - kg * - g - Gravity - m/s\ :sup:`2` * - GAMSS - Input, fraction of power going into direct heating of structure - * - GAMTNC - Input, fraction of power going into direct heating of coolant - * - GAMTNE - Input, fraction of power going in to direct heating of cladding - * - h - Heat-transfer coefficient - J/(m\ :sup:`2`\ ·s·K) * - H - Heat-transfer coefficient times heat-transfer area - J/(s·K) * - I - Axial node index in coolant channel - * - IDIFF - Offset between pin and channel grid. The first pin node is at the same elevation as channel node IDIFF + 1 - * - k - Conductivity - J(m·s·K) * - K - Axial index in the pin - * - KKMX - Uppermost node in the molten pin cavity - * - KZPIN - Coolant channel zone which contains the fuel pins - * - KK1 - Lowermost node in the molten pin cavity - * - L - Length - m * - NRPI - Number of pins per subassembly - * - NT - Number of radial fuel pin nodes - * - Nu - Nusselt number - * - P - Pressure - Pa * - PORFR - Porosity fraction - * - POW - Input, power in highest rated axial fuel pin node - W * - POWCOF - Exponent in the exponential function which gives the power history during a neutron's time step - * - Pr - Prandtl number - * - PSHAPE - Input, axial pin power shape - * - PSHAPR - Input, radial power shape in a pin - * - Q - Fission heat source - * - r - Radius - W/kg * - R - Gas constant or radius - J/(kg·K) * - RETFG2 - Total fission gas mass in the radial fuel pin node at the cavity boundary before it began melting into the cavity - kg * - Re - Reynold's number - * - RGAS - Input, gas constant for fission gas - J(kg·K) * - S - Mass sink or source - kg/s * - S' - Mass sink or source per unit of generalized smear volume - kg/(m·s) * - St - Stanton number - * - t - Time - S * - T - Temperature - K * - u - Velocity - m/s * - VIFG - Input, viscosity of fission gas - kg/(m·s) * - VIFULQ - Input, viscosity of liquid fuel - kg/(m·s) * - VOLUME - Volume - m\ :sup:`3` * - z - Axial coordinate - m