The thermal-hydraulic reactor model is combined with the point kinetic model to calculate the coolant flow rates, as well as the inlet and outlet temperatures of the reactor core. Thermal-hydraulic reactor models have been made with 1.5D fractional calculus. This model uses a lumped core model with forced convection for cooling the fuel rods. This solves the mass, energy, and momentum balance equations. All of the fuel rods are represented by an average fuel rod, and the model assumes thermal equilibrium. The fuel rod is then discretized into \(N\) axial segments to represent the axial power distribution in the core.
In this model, the reactivity feedback can be described by the following equation
$$\sum \rho_{fb}=\rho_{f(T)}+\rho_{m(T)}+\rho_{m(P)}+\rho_{C(T)}+\rho_{s(T)}$$
Where the reactivity feedback is a 4th-order polynomial function of temperature and pressure (or boron concentration for the temperature function)
| Term | Description |
| \(\rho_{f(T)}\) | uel temperature reactivity feedback due to thermal expansion and doppler broadening of the neutron cross-section |
| \(\rho_{m(T)}\) | moderator temperature reactivity. This accounts for the soluble Boron concentration |
| \(\rho_{m(P)}\) | moderator density reactivity feedback as a function of pressure |
| \(\rho_{C(T)}\) | cladding temperature reactivity feedback due to thermal expansion and doppler broadening |
| \(\rho_{s(T)}\) | temperature resistivity feedback of the barrel and support plate |
The thermal power of the reactor equals the fission power multiplied by the recoverable energy fraction \(f_{rec}\). This fraction can be between 0.85-0.9.
$$P_{rx}=f_{rec}P$$
Where \(P_{rx}\) is the thermal power of the reactor, and \(P\) is the fission power of the reactor.
Fuel Rod Thermal Model
Energy Balance Equations for the Thermal Hydraulic Reactor Model
Thermal Conductivity in Radial Fuel Rod Gap
Challenges of Nuclear Thermal Rockets – the thermodynamic gas and reactor dynamics must be coupled.
Asco Reactor Thermal Hydraulic Model
Nuclear Reactor Load Rejection Test – tests the TH in an entire reactor simulation
Implicit Integration Methods – gives an example of implicit reactor thermal model
[[TRIGA Mk 2 Thermal Hydraulic Model]]
[[Criticality Accident]] – radioactive material deposited on the reactor cooling system as a result of an accident may have an affect on the thermal hydraulics of the system
TRAP-MELT – thermohydraulic analysis code
[[VICTORIA]]
Submarine Reactor Thermal Model – model for thermal reactor
Sources
- [1] M. S. El-Genk, T. Schriener, A. Hahn, and R. Altamimi, “A Physics-based, Dynamic Model of a Pressurized Water Reactor Plant with Programmable Logic Controllers for Cybersecurity Applications”.
- Sort_47366
Backlinks
[[Discretization]]
[[Fractional Calculus]]
Lumped Parameter Model
Point Reactor Kinetics Model
Pressurized Water Reactors