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Technical Papers

Coupling of Neutronics and Thermal-Hydraulic Codes for Simulation of the MNSR Reactor

ORCID Icon, , &
Pages 1276-1289 | Received 05 Jan 2019, Accepted 21 May 2019, Published online: 17 Jun 2019


This study aims to evaluate a simplified one-dimensional thermal-hydraulic module (THM) established by the DRAGON5/DONJON5 codes that allow a multiphysics study of the Syrian Miniature Neutron Source Research (MNSR) reactor both in steady-state and transient conditions. The purpose of this paper is therefore to describe the THM, fully integrated and implanted in DONJON5 to allow coupling with neutronic modules existing in the same code and to perform steady-state thermal-hydraulic and safety analyses of the reactor. Then we compare the results given by the THM with the results obtained by the Program for the Analysis of REactor Transients (PARET)/Argonne National Laboratory (ANL) thermal-hydraulic code. In order to validate our PARET/ANL and the THM in DONJON5, the fuel center temperature as a function of core power was calculated and compared with the corresponding values of the PARET code. Moreover, we have calculated the departure from nucleate boiling ratio. The comparison of the results of this study showed a good correlation between the values obtained with the THM and the thermal-hydraulic PARET/ANL code.


A ==

cross-sectional area (m2)

Af ==

cross section of the fuel (m2)

Cf ==

circle of clad (m)

Cp ==

specific heat (J/kg·K)

De ==

equivalent hydraulic diameter (m)

do ==

fuel diameter (m)

f ==

friction factor

G ==

coolant mass flux (kg/s·m2)

g ==

gravitational acceleration (m/s2)

h ==

enthalpy (J/kg)

H ==

height of the inlet orifice (mm)

m˙ ==

mass flow rate (kg/s)

P ==

pressure (Pa)

Pw ==

wetted perimeter of the cross section (m)

q ==

heat source per unit volume

q′′′ ==

heat flux (W/m3)

qActual ′′ ==

actual heat flux (W/m2)

qCHF ′′ ==

critical heat flux (W/m2)

T ==

temperature (K)

Ti ==

inlet core coolant temperature (◦C)

u ==

velocity of the coolant (m/s)


α ==

vapor volume fraction (void fraction)

βeff ==

delayed neutron fraction

Δ ==



gradient operator

µ ==

dynamic viscosity (Pa·s)

ρ ==

average coolant density (kg/m3)

ρ′ ==

effective densities pertaining to the momentum equation

ρ″ ==

effective densities pertaining to the energy equation

ρl,ρv ==

saturated liquid and vapor densities, respectively

p/z ==

pressure gradient

τ ==

shear stress (N/m2)

ψ ==

pressure (MPa)

χ ==

vapor weight fraction (mass quality)


CHF ==

critical heat flux

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