8. Block Parameters¶
This document lists all of the Block Parameters that are provided by the ARMI Framework and included plugins.
Block Parameters from Framework¶ Name
Description
Units
orientation
Triple representing rotations counterclockwise around each spatial axis. For example, a hex assembly rotated by 1/6th has orientation (0,0,60.0)
degrees
pinLocation
Location of fuel pins
None
detailedNDens
High-fidelity number density vector with up to thousands of nuclides. Used in high-fi depletion runs where low-fi depletion may also be occurring. This param keeps the hi-fi and low-fi depletion values from interfering. See core.p.detailedNucKeys for keys.
atoms/bn-cm
burnupMWdPerKg
Burnup in MWd/kg of initial heavy metal
MWd/kg
fissileFraction
Ratio of fissile mass to heavy metal mass at block-level
None
molesHmBOL
Total number of atoms of heavy metal at BOL assuming a full assembly
mole
massHmBOL
Mass of heavy metal at BOL
grams
initialB10ComponentVol
cc’s of un-irradiated, cold B10 containing component (includes full volume if any B10)
cc
molesHmBOLByPin
Total number of atoms of heavy metal at BOL
mole
molesHmNow
Total number of atoms of heavy metal
mole
newDPA
Dose in DPA accrued during the current time step
dpa
percentBu
Percentage of the initial heavy metal atoms that have been fissioned
%FIMA
percentBuByPin
Percent burnup of the initial heavy metal atoms that have been fissioned for each pin
%FIMA
percentBuMax
Maximum percentage in a single pin of the initial heavy metal atoms that have been fissioned
%FIMA
percentBuMaxPinLocation
Peak burnup pin location
int
percentBuMin
Minimum percentage of the initial heavy metal atoms that have been fissioned
%FIMA
residence
Duration that a block has been in the core at full power.
EFP days
depletionMatrix
Full BurnMatrix objects containing transmutation and decay info about this block.
N/A
cycleAverageBurnMatrix
Integrated burn matrix mapping this block from its BOC to EOC number densities.
N/A
bu
?
buGroup
The burnup group letter of this block
N/A
buGroupNum
An integer representation of the burnup group, linked to buGroup.
N/A
buRate
Current rate of burnup accumulation. Useful for estimating times when burnup limits may be exceeded.
%FIMA/day
buRatePeak
Current rate of burnup accumulation at peak location
%FIMA/day spatial peak
detailedDpa
displacements per atom
dpa
detailedDpaPeak
displacements per atom with peaking factor
dpa
detailedDpaRate
Current time derivative of average detailed DPA
dpa/s
displacementX
Assembly displacement in the x direction
m
displacementY
Assembly displacement in the y direction
m
powerRx
?
W/cm$^3$
heliumInB4C
?
He/s/cm$^3$
timeToLimit
Time unit block violates its burnup limit.
days
zbottom
Axial position of the bottom of this block
cm
ztop
Axial position of the top of this block
cm
baseBu
?
?
basePBu
?
?
nHMAtBOL
Ndens of heavy metal at BOL
atoms/bn-cm.
z
Center axial dimension of this block
cm
axialExpTargetComponent
The name of the target component used for axial expansion and contraction of solid components.
topIndex
(‘the axial block index within its parent assembly (0 is bottom block). This index withregard to the mesh of the reference assembly so it does not increase by 1 for each block.It is used to keep the mesh of the assemblies uniform with axial expansion.See setBlockMesh, makeAxialSnapList’,)
eqRegion
Equilibrium shuffling region. Corresponds to how many full cycles fuel here has gone through.
eqCascade
Cascade number in repetitive equilibrium shuffling fuel management.
id
?
?
height
the block height
cm
xsType
The xs group letter of this block
N/A
xsTypeNum
An integer representation of the cross section type, linked to xsType.
N/A
type
string name of the input block
N/A
VoideddopplerWorth
Distributed Voided Doppler constant.
dk/kk’ K**(n-1)
dopplerWorth
Distributed Doppler constant.
dk/kk’ * K^(n-1)
fuelWorth
Reactivity worth of fuel material per unit mass
dk/kk’-kg
fuelWorthPT
Fuel reactivity
pcm/%/cm^3
structWorthPT
Structure reactivity
pcm/%/cm^3
radExpWorthPT
Radial swelling reactivity
pcm/%/cm^3
coolWorthPT
Coolant reactivity
pcm/%/cm^3
coolFlowingWorthPT
Flowing coolant reactivity
pcm/%/cm^3
axExpWorthPT
Axial swelling reactivity
pcm/%/cm^3
coolantWorth
Reactivity worth of coolant material per unit mass
dk/kk’-kg
cladWorth
Reactivity worth of clad material per unit mass
dk/kk’-kg
rxAxialCentsPerK
Axial temperature reactivity coefficient
cents/K
rxAxialCentsPerPow
Axial power reactivity coefficient
cents/K
rxCoolantCentsPerK
Coolant temperature reactivity coefficient
cents/K
rxCoolantCentsPerPow
Coolant power reactivity coefficient
cents/K
rxDopplerCentsPerK
Doppler temperature reactivity coefficient
cents/K
rxDopplerCentsPerPow
Doppler power reactivity coefficient
cents/K
rxFuelCentsPerK
Fuel temperature reactivity coefficient
cents/K
rxFuelCentsPerPow
Fuel power reactivity coefficient
cents/K
rxNetCentsPerK
Net temperature reactivity coefficient
cents/K
rxNetCentsPerPow
Net power reactivity coefficient
cents/K
rxNetPosNeg
Net temperature reactivity coefficient: positive or negative
cents/K
rxNetPosNegPow
Net power reactivity coefficient: positive or negative
cents/K
rxRadialCentsPerK
Radial temperature reactivity coefficient
cents/K
rxRadialCentsPerPow
Radial power reactivity coefficient
cents/K
rxStructCentsPerK
Structure temperature reactivity coefficient
cents/K
rxStructCentsPerPow
Structure power reactivity coefficient
cents/K
rxVoidedDopplerCentsPerK
Voided Doppler temperature reactivity coefficient
cents/K
rxVoidedDopplerCentsPerPow
Voided Doppler power reactivity coefficient
cents/K
rxFuelDensityCoeffPerMass
Fuel Density Coefficient
dk/kk’-kg
rxFuelDopplerConstant
Fuel Doppler Constant
dk/kk’ K**(n-1)
rxFuelVoidedDopplerConstant
Fuel Voided-Coolant Constant
dk/kk’ K**(n-1)
rxFuelTemperatureCoeffPerMass
Fuel Temperature Coefficient
dk/kk’-kg
rxFuelVoidedTemperatureCoeffPerMass
Fuel Voided-Coolant Temperature Coefficient
dk/kk’-kg
rxCladDensityCoeffPerMass
Clad Density Coefficient
dk/kk’-kg
rxCladDopplerConstant
Clad Doppler Constant
dk/kk’ K**(n-1)
rxCladTemperatureCoeffPerMass
Clad Temperature Coefficient
dk/kk’-kg
rxStructureDensityCoeffPerMass
Structure Density Coefficient
dk/kk’-kg
rxStructureDopplerConstant
Structure Doppler Constant
dk/kk’ K**(n-1)
rxStructureTemperatureCoeffPerMass
Structure Temperature Coefficient
dk/kk’-kg
rxCoolantDensityCoeffPerMass
Coolant Density Coefficient
dk/kk’-kg
rxCoolantTemperatureCoeffPerMass
Coolant Temperature Coefficient
dk/kk’-kg
rxFuelDensityCoeffPerTemp
Fuel Density Coefficient
dk/kk’-K
rxFuelDopplerCoeffPerTemp
Fuel Doppler Coefficient
dk/kk’-K
rxFuelVoidedDopplerCoeffPerTemp
Fuel Voided-Coolant Doppler Coefficient
dk/kk’-K
rxFuelTemperatureCoeffPerTemp
Fuel Temperature Coefficient
dk/kk’-K
rxFuelVoidedTemperatureCoeffPerTemp
Fuel Voided-Coolant Temperature Coefficient
dk/kk’-K
rxCladDensityCoeffPerTemp
Clad Density Coefficient
dk/kk’-K
rxCladDopplerCoeffPerTemp
Clad Doppler Coefficient
dk/kk’-K
rxCladTemperatureCoeffPerTemp
Clad Temperature Coefficient
dk/kk’-K
rxStructureDensityCoeffPerTemp
Structure Density Coefficient
dk/kk’-K
rxStructureDopplerCoeffPerTemp
Structure Doppler Coefficient
dk/kk’-K
rxStructureTemperatureCoeffPerTemp
Structure Temperature Coefficient
dk/kk’-K
rxCoolantDensityCoeffPerTemp
Coolant Density Coefficient
dk/kk’-K
rxCoolantTemperatureCoeffPerTemp
Coolant Temperature Coefficient
dk/kk’-K
assemNum
Index that refers, nominally, to the assemNum parameter of the containing Assembly object. This is stored on the Block to aid in visualizing shuffle patterns and the like, and should not be used within the code. These are not guaranteed to be consistent with the containing Assembly, so they should not be used as a reliable means to reconstruct the model.
None
avgFuelTemp
?
?
avgTempRef
?
?
axExtenNodeHeight
Axial extension node height
meter
blockBeta
Beta in each block
unitless
blockF
Adjoint-weighted fission source in each block
1/cm^5/s^2
breedRatio
Breeding ratio
None
fissileDestroyed
Fissile atoms destroyed in last depletion step (not net!)
atoms/bn-cm
fissileBefore
Fissile atoms at beginning of last depletion step (could be substep!)
atoms/bn-cm
fissileAfter
Fissile atoms at end of last depletion step (could be substep!)
atoms/bn-cm
buLimit
Burnup limit
%FIMA
cladACCI
The amount of cladding wastage due to absorber chemical clad interaction
µm
convRatio
Conversion ratio
None
coolRemFrac
Fractional sodium density change for each block
?
crWastage
Combines ACCI and clad corrosion for control blocks
µm
cyclicNErr
Relative error of the block number density
None
deltaTclad
Change in fuel temperature due to 1% rise in power.
1/cm^5/s^2
deltaTduct
Change in fuel temperature due to 1% rise in power.
1/cm^5/s^2
deltaTfuel
Change in fuel temperature due to 1% rise in power.
1/cm^5/s^2
heightBOL
As-fabricated height of this block (as input). Used in fuel performance. Should be constant.
cm
intrinsicSource
Intrinsic neutron source from spontaneous fissions before a decay period
?
intrinsicSourceDecayed
Intrinsic source from spontaneous fissions after a decay period
?
kgFis
Mass of fissile material in block
kg
kgHM
Mass of heavy metal in block
kg
mchan
SASSYS/DIF3D-K (external) channel index assignment
None
mreg
SASSYS/DIF3D-K radial region index assignment
None
nPins
Number of pins
None
newDPAPeak
The peak DPA accumulated in the last burn step
dpa
percentBuPeak
Peak percentage of the initial heavy metal atoms that have been fissioned
%FIMA
powerShapeDelta
Change in power shape when core temperature rises.
W
puFrac
Current Pu number density relative to HM at BOL
None
smearDensity
Smear density of fuel pins in this block. Defined as the ratio of fuel area to total space inside cladding.
?
Block Parameters from ThermalHydraulicsPlugin¶ Name
Description
Units
pressureLossCoeffs
Pressure loss coefficients from form losses outside of bundle region of assembly, e.g. losses through pin attachment hardware, expansion in inlet nozzle.
THhotChannelCladMidwallT
Midwall (average) clad temperature for the hot channel or hot pin.
°C
THhotChannelHeatTransferCoeff
Film heat transfer coefficient for hot channel in the assembly.
W/m^2/K
THhotChannelCladODT
Nominal clad outer diameter temperature of the hot pin
°C
THhotChannelCladIDT
Nominal clad inner diameter temperature of the hot pin
°C
THhotChannelFuelODT
Temperature of the fuel outer diameter
°C
THhotChannelFuelCenterlineT
Nominal hot channel fuel centerline temperature
°C
TH0SigmaCladODT
0-sigma clad outer diameter temperature of the hot pin
°C
TH2SigmaCladODT
2-sigma clad outer diameter temperature of the hot pin
°C
TH3SigmaCladODT
3-sigma clad outer diameter temperature of the hot pin
°C
TH0SigmaCladIDT
0-sigma clad inner diameter temperature of the hot pin
°C
TH2SigmaCladIDT
2-sigma clad inner diameter temperature of the hot pin
°C
TH3SigmaCladIDT
3-sigma clad inner diameter temperature of the hot pin
°C
THdilationPressure
Dilation pressure
Pa
THTfuelCL
Average temperature of the fuel centerline used for neutronic coupling
°C
THTfuelOD
Average temperature of the fuel outer diameter used for neutronic coupling
°C
THaverageCladODT
Block average of the outer clad temperature.
°C
THaverageCladIDT
Block average of the inner clad temperature
°C
THaverageCladTemp
The nominal average clad temperature in the block, which should be used for neutronic and TH feedback.
°C
THaverageGapTemp
The nominal average gap temperature in the block, which should be used for neutronic and TH feedback.
°C
THaverageDuctTemp
The nominal average duct temperature in the block, which should be used for neutronic and TH feedback.
°C
THcoolantAverageT
Flow-based average of the inlet and outlet coolant temperatures.
°C
THcoolantInletT
The nominal average bulk coolant inlet temperature into the block.
°C
THcoolantOutletT
Coolant temperature at the outlet of this block
°C
THcoolantStaticT
Volume-based average coolant temperature, recommended for neutronics
°C
THdeltaPTotal
Total pressure difference in a block
Pa
THhotChannelOutletT
Nominal hot channel outlet temperature
°C
THlocalDTout
Maximum delta-Ts for outlet temperatures of all assemblies
°C
THlocalDToutFuel
Maximum delta-Ts for outlet temperatures of fuel assemblies
°C
THmassFlowRate
Mass flow rate
kg/s
THorificeZone
A list of orificing zones corresponding to the assembly list
THcornTemp
Best estimate duct temperature [degC] for assembly corners
°C
THedgeTemp
Best estimate duct temperature for assembly edges
°C
THhotChannel
Hot channel (highest coolant dT) identifier
Block Parameters from NeutronicsPlugin¶ Name
Description
Units
axMesh
number of neutronics axial mesh points in this block
mgFlux
multigroup volume-integrated flux
n-cm/s
adjMgFlux
multigroup adjoint neutron flux
n-cm/s
lastMgFlux
multigroup volume-integrated flux used for averaging the latest and previous depletion step
n-cm/s
mgFluxGamma
multigroup gamma flux
g-cm/s
mgNeutronVelocity
multigroup neutron velocity
cm/s
extSrc
multigroup external source
g/cm^3/s
mgGammaSrc
multigroup gamma source
g/cm^3/s
gammaSrc
gamma source
g/cm^3/s
mgFluxSK
multigroup volume-integrated flux stored for multiple time steps in spatial kinetics (2-D array)
pinMgFluxes
The block-level pin multigroup fluxes. pinMgFluxes[g][i] represents the flux in group g for pin i. Flux units are the standard n/cm^2/s. The “ARMI pin ordering” is used, which is counter-clockwise from 3 o’clock.
n/s/cm$^2$
pinMgFluxesAdj
should be a blank 3-D array, but re-defined later (ng x nPins x nAxialSegments)
pinMgFluxesGamma
should be a blank 3-D array, but re-defined later (ng x nPins x nAxialSegments)
g/s/cm$^2$
axialPowerProfile
For each reconstructed axial location, a tuple (z,power density) where with axial origin at the bottom of assembly in which the blocks are located.
axialPowerProfileNeutron
axialPowerProfileGamma
betad
Delayed neutron beta
chi
Energy distribution of fission neutrons
chid
Energy distribution of delayed fission neutrons
linPow
Pin-averaged linear heat rate, which is calculated by evaluating the block power and dividing by the number of pins. If gamma transport is enabled, then this represents the combined neutron and gamma heating. If gamma transport is disabled then this represents the energy generation in the pin, where gammas are assumed to deposit their energy locally. Note that this value does not implicitly account for axial and radial peaking factors within the block. Use linPowByPin for obtaining the pin linear heat rate with peaking factors included.
W/m
linPowByPin
Pin linear linear heat rate, which is calculated through flux reconstruction and accounts for axial and radial peaking factors. This differs from the linPow parameter, which assumes no axial and radial peaking in the block as this information is unavailable without detailed flux reconstruction. The same application of neutron and gamma heating results applies.
W/cm
linPowByPinNeutron
Pin linear neutron heat rate. This is the neutron heating component of linPowByPin
W/cm
linPowByPinGamma
Pin linear gamma heat rate. This is the gamma heating component of linPowByPin
W/cm
reactionRates
List of reaction rates in specified by setting “reactionsToDB”
#/s
pointsEdgeFastFluxFr
Fraction of flux above 100keV at edges of the block
None
pointsEdgeDpa
displacements per atom at edges of the block
dpa
pointsEdgeDpaRate
Current time derivative of the displacement per atoms at edges of the block
dpa/s
cornerFastFlux
Neutron flux above 100keV at hexagon block corners
n/cm^2/s
pointsCornerFastFluxFr
Fraction of flux above 100keV at corners of the block
None
pointsCornerDpa
displacements per atom at corners of the block
dpa
pointsCornerDpaRate
Current time derivative of the displacement per atoms at corners of the block
dpa/s
rateBalance
Numerical balance between particle production and destruction (should be small)
1/cm^3/s
rateExtSrc
Rate of production of neutrons from an external source.
1/cm^3/s
rateFisAbs
Neutron abs. rate in fissile material
1/cm^3/s
rateFisSrc
Fission source rate. This is related to production rate in fissile by a factor of keff
1/cm^3/s
rateLeak
Rate that neutrons leak out of this block.
1/cm^3/s
rateParasAbs
Rate of parasitic absorption (absorption in non-fertile/fissionable material)
1/cm^3/s
rateProdNet
Net production rate of neutrons
1/cm^3/s
rateScatIn
Rate neutrons in-scatter in this block
1/cm^3/s
rateScatOut
Rate that neutrons out-scatter in this block (removal - absorption)
1/cm^3/s
capturePowerFrac
Fraction of the power produced through capture in a block.
None
fastFluence
Fast spectrum fluence
#/cm^2
fastFluencePeak
Fast spectrum fluence with a peaking factor
#/cm^2
fluence
Fluence
#/cm^2
flux
neutron flux
n/cm^2/s
fluxAdj
Adjoint flux
fluxAdjPeak
Adjoint flux
pdens
Average volumetric power density
W/cm$^3$
pdensDecay
Decay power density from decaying radionuclides
W/cm$^3$
arealPd
Power divided by XY area
MW/m^2
fertileBonus
The fertile bonus
None
fisDens
Fission density in a pin (scaled up from homogeneous)
fissions/cm^3/s
fisDensHom
Homogenized fissile density
1/cm^3/s
fluxGamma
Gamma scalar flux
g/cm^2/s
fluxPeak
Peak neutron flux calculated within the mesh
n/cm^2/s
kInf
Neutron production rate in this block/neutron absorption rate in this block. Not truly kinf but a reasonable approximation of reactivity.
None
medAbsE
Median neutron absorption energy
eV
medFisE
Median energy of neutron causing fission
eV
medFlxE
Median neutron flux energy
eV
pdensGamma
Average volumetric gamma power density
W/cm^3
pdensNeutron
Average volumetric neutron power density
W/cm^3
ppdens
Peak power density
W/cm^3
ppdensGamma
Peak gamma density
W/cm^3
rateAbs
Total absorption rate in this block (fisson + capture).
1/cm^3/s
rateCap
Parasitic capture rate in this block.
1/cm^3/s
rateProdN2n
Production rate of neutrons from n2n reactions.
1/cm^3/s
rateFis
Fission rate in this block.
1/cm^3/s
rateProdFis
Production rate of neutrons from fission reactions (nu * fission source / k-eff)
1/cm^3/s
powerGenerated
Generated power. Different than b.p.power only when gamma transport is activated.
W
power
Total power
W
powerDecay
Total decay power
W
powerGamma
Total gamma power
W
powerNeutron
Total neutron power
W
detailedDpaThisCycle
Displacement per atom accumulated during this cycle. This accumulates over a cycle and resets to zero at BOC.
dpa
detailedDpaPeakRate
Peak DPA rate based on detailedDpaPeak
DPA/s
dpaPeakFromFluence
DPA approximation based on a fluence conversion factor set in the dpaPerFluence setting
dpa
enrichmentBOL
Enrichment during fabrication
mass fraction
fastFlux
Neutron flux above 100keV
1/cm^2/s
fastFluxFr
Fraction of flux above 100keV
pdensGenerated
Volume-averaged generated power density. Different than b.p.pdens only when gamma transport is activated.
W/cm^3
Block Parameters from FuelPerformancePlugin¶ Name
Description
Units
fuelCladLocked
Boolean to indicate if the fuel is locked with the clad. This is used to determine the expansion constraints for the fuel during thermal and/or burn-up expansion of the fuel and cladding materials.
gasReleaseFraction
Fraction of generated fission gas that no longer exists in the block.
fraction
bondRemoved
Fraction of thermal bond between fuel and clad that has been pushed out.
fraction
cladWastage
Total cladding wastage from inner and outer surfaces.
µm
totalCladStrain
Total diametral clad strain.
%
axialGrowthPct
Axial growth percentage
%
fpPeakFuelTemp
Fuel performance calculated peak fuel temperature.
C
fpAveFuelTemp
Fuel performance calculated average fuel temperature.
C
gasPorosity
Fraction of fuel volume that is occupied by gas pores
liquidPorosity
Fraction of fuel volume that is occupied by liquid filled pores