Development and Verification of Dynamics Code for Molten Salt Reactors

2004 ◽  
Author(s):  
Jiri Krepel ◽  
Ulrich Grundmann ◽  
Ulrich Rohde
Keyword(s):  
Molten Salt ◽  
Liquid Fuel ◽  
Expansion Method ◽  
Primary Circuit ◽  
Fuel System ◽  
Delayed Neutrons ◽  
Flow Acceleration ◽  
Fuel Flow ◽  
Reactor Dynamics ◽  
Reactivity Increase

To perform transient analysis for Molten Salt Reactors (MSR), the reactor dynamics code DYN3D developed in FZR was modified for MSR applications. The MSR as a liquid fuel system can serve as a thorium breeder and also as an actinide burner. The specifics of the reactor dynamics of MSR consist in the fact, that there is direct influence of the fuel velocity to the reactivity, which is caused by the delayed neutrons precursors drift. This drift causes the spread of delayed neutrons distribution to the non-core parts of primary circuit. This leads to a reactivity loss due to the fuel flow acceleration or to the reactivity increase in the case of deceleration. For the first analyses, a 1D modified version DYN1D-MSR of the code has been developed. By means of the DYN1D-MSR, several transients typical for the liquid fuel system were analyzed. Transients due to the overcooling of fuel at the core inlet, due to the reactivity insertion, and the fuel pump trip have been considered. The results of all transient studies have shown that the dynamic behavior of MSR is stable when the coefficients of thermal feedback are negative. For studying space-dependent effects like e.g. local blockages of fuel channels, a 3D code version DYN3D-MSR will be developed. The nodal expansion method used in DYN3D for hexagonal fuel element geometry of VVER can be applied considering MSR design with hexagonal graphite channels.

A Novel Molten Salt Reactor Concept to Implement the Multi-Step Time-Scheduled Transmutation Strategy

2002 ◽  
Author(s):  
Gyula Csom ◽  
Sandor Feher ◽  
Mate Szieberth
Keyword(s):  
Molten Salt ◽  
Liquid Fuel ◽  
Primary Circuit ◽  
Chemical Processing ◽  
Molten Salt Reactor ◽  
The Core ◽  
Continuous Feed ◽  
Fuel Mixtures ◽  
Continuous Chemical ◽  
Optimal Implementation

Nowadays the molten salt reactor (MSR) concept seems to revive as one of the most promising systems for the realization of transmutation. In the molten salt reactors and subcritical systems the fuel and material to be transmuted circulate dissolved in some molten salt. The main advantage of this reactor type is the possibility of the continuous feed and reprocessing of the fuel. In the present paper a novel molten salt reactor concept is introduced and its transmutational capabilities are studied. The goal is the development of a transmutational technique along with a device implementing it, which yield higher transmutational efficiencies than that of the known procedures and thus results in radioactive waste whose load on the environment is reduced both in magnitude and time length. The procedure is the multi-step time-scheduled transmutation, in which transformation is done in several consecutive steps of different neutron flux and spectrum. In the new MSR concept, named “multi-region” MSR (MRMSR), the primary circuit is made up of a few separate loops, in which salt-fuel mixtures of different compositions are circulated. The loop sections constituting the core region are only neutronically and thermally coupled. This new concept makes possible the utilization of the spatial dependence of spectrum as well as the advantageous features of liquid fuel such as the possibility of continuous chemical processing etc. In order to compare a “conventional” MSR and a proposed MRMSR in terms of efficiency, preliminary calculational results are shown. Further calculations in order to find the optimal implementation of this new concept and to emphasize its other advantageous features are going on.

COUPLE, A Time-Dependent Coupled Neutronics and Thermal-Hydraulics Code, and its Application to MSFR

2014 ◽  
Author(s):  
Dalin Zhang ◽  
Zhi-Gang Zhai ◽  
Andrei Rineiski ◽  
Zhangpeng Guo ◽  
Chenglong Wang ◽  
...  
Keyword(s):  
Molten Salt ◽  
Liquid Fuel ◽  
Time Dependent ◽  
Molten Salt Reactor ◽  
Thermal Hydraulics ◽  
Delayed Neutron ◽  
Fuel Flow ◽  
Reactor Optimization ◽  
Fuel Characteristics ◽  
Significant Attention

Molten salt reactor (MSR) using liquid fuel is one of the Generation-IV candidate reactors. Its liquid fuel characteristics are fundamentally different from those of the conventional solid-fuel reactors, especially the much stronger neutronics and thermal hydraulics coupling is drawing significant attention. In this study, the fundamental thermal hydraulic model, neutronic model, and some auxiliary models were established for the liquid-fuel reactors, and a time-dependent coupled neutronics and thermal hydraulics code named COUPLE was developed to solve the mathematic models by the numerical method. After the code was verified, it was applied to the molten salt fast reactor (MSFR) to perform the steady state calculation. The distributions of the neutron fluxes, delayed neutron precursors, velocity, and temperature were obtained and presented. The results show that the liquid fuel flow affects the delayed neutron precursors significantly, while slightly influences the neutron fluxes. The flow in the MSFR core generates a vortex near the fertile tank, which leads to the maximal temperature about 1100 K at the centre of the vortex. The results can provide some useful information for the reactor optimization.

Adjoint‐based sensitivity analysis of circulating liquid fuel system for the multiphysics model of molten salt reactor

2020 ◽  
Vol 44 (5) ◽  
pp. 3934-3953
Author(s):  
Yeong Shin Jeong ◽  
Eric Cervi ◽  
Antonio Cammi ◽  
Hisashi Ninokata ◽  
In Cheol Bang
Keyword(s):  
Sensitivity Analysis ◽  
Molten Salt ◽  
Liquid Fuel ◽  
Molten Salt Reactor ◽  
Fuel System

Study on the Coupled Neutronic and Thermal-Hydraulic Characteristics of the New Concept Molten Salt Reactor

2009 ◽  
Author(s):  
Peng Wang ◽  
Suizheng Qiu
Keyword(s):  
Molten Salt ◽  
Flow Velocity ◽  
Design Theory ◽  
Primary Circuit ◽  
Molten Salt Reactor ◽  
Hydraulic Characteristics ◽  
Delayed Neutron ◽  
Delayed Neutrons ◽  
Flow Effect ◽  
Fuel Salt

The new concept Molten Salt Reactor is the only liquid-fuel reactor of the six Generation IV advanced nuclear energy systems. The liquid molten salt serves as the fuel and coolant simultaneously and causes one important feature: the delayed neutrons precursors are drifted by the fuel flow, which leads the spread of delayed neutrons distribution to non-core parts of the primary circuit, and it also can result in a reactivity variation depending on the flow condition of the fuel salt. Therefore, the neutronic and thermal-hydraulic characteristics of the Molten Salt Reactor is quite different from the conventional nuclear reactors using solid fissile materials, and no other reactor design theory and safety analysis methodologies can be used for reference. The neutronic model is derived based on the conservation of particle considering the flow effect of the fuel salt in the Molten Salt Reactor, while the thermal-hydraulic model uses the fundamental conservation laws: the mass, momentum and energy conservation equations. Then the neutronic and thermal-hydraulic calculations were coupled and the influences of inflow temperature and flow velocity on the reactor physical properties were obtained. The calculated results show that the flow effect on the distributions of thermal and fast neutron fluxes is very weak, as well as on the effective multiplication factor keff. While the flow effect on the distribution of delayed neutron precursors is much stronger. The inflow temperature influences the distribution of neutron flux and delayed neutron precursors slightly, and makes significant negative reactivity. Coupled calculation also reveals that the flow velocity of molten salt has little effect on the distribution of neutron fluxes in the steady state, but affects the delayed neutron precursors’ distribution significantly.

Signatures of plutonium diversion in Molten Salt Reactor dynamics

2021 ◽  
Vol 160 ◽  
pp. 108370
Author(s):  
Alexander M. Wheeler ◽  
Ondřej Chvála ◽  
Steven Skutnik
Keyword(s):  
Molten Salt ◽  
Molten Salt Reactor ◽  
Reactor Dynamics

Development of the Electric Fuel System for the More Electric Engine

2014 ◽  
Author(s):  
Noriko Morioka ◽  
Hitoshi Oyori ◽  
Yukinori Gonda ◽  
Kenji Takamiya ◽  
Yasuhiko Yamamoto
Keyword(s):  
Electric Motor ◽  
Aircraft Engine ◽  
Fuel System ◽  
Motor Speed ◽  
Pump System ◽  
Fuel Pump ◽  
Fuel Flow ◽  
Set Up ◽  
Electric Fuel Pump ◽  
Electric Engine

This paper describes the experimental rig test result of the electric motor-driven fuel pump system for the MEE (More Electric Engine). The MEE is an aircraft engine system concept, which replaces conventional mechanical/hydraulic driven components with electric motor-driven components. Various MEE approaches have been studied since the early 2000s and one of its key concepts is an electric motor-driven fuel pump [1–4]. The authors commenced a feasibility study of the electric motor-driven gear pump system for what was assumed to be a small-sized turbofan engine. The concept study and system design were conducted, whereupon technical issues for the electric fuel pump system, which both supplies and meters fuel via the motor speed control, were clarified [5, 6]. Since one of the key issues is fuel-metering accuracy, the electric fuel system, including a flow feedback closed-loop control, was designed to ensure accurate fuel-flow metering for aircraft engine applications. To verify the rig system, an experimental model of the electric fuel pump system is assumed for a small-sized turbofan engine. The hardware of the motor-driven fuel pump and flow measurement mechanism, including an FPV (Fuel-Pressurizing Valve) and orifice, were designed, manufactured and fabricated and a differential pressure sensor for flow feedback was selected. Other equipment was also prepared, including a motor controller, power source and measurement devices, and the entire rig set-up was constructed. A bench test using the rig test set-up was conducted to verify the fuel-metering accuracy, response and system stability. Data, including the static performance and frequency response, were obtained for the electric motor, motor-driven fuel pump and entire fuel system respectively. The rig test results indicate the feasibility of the system, which will provide an accurate engine fuel flow (Wf) measurement and frequency response required for actual engine operation, via an electric motor speed control and fuel-flow feedback system, as proposed in the MEE electric fuel system.

scholarly journals Experimental Investigation of the Liquid Fuel Evaporation in a Premix Duct for Lean Premixed and Prevaporized Combustion

1996 ◽  
Author(s):  
Michael Brandt ◽  
Kay O. Gugel ◽  
Christoph Hassa
Keyword(s):  
Experimental Investigation ◽  
Air Temperature ◽  
Flow Rate ◽  
Liquid Fuel ◽  
Operating Conditions ◽  
Dispersion Characteristics ◽  
Fuel Flow Rate ◽  
Fuel Flow ◽  
Lean Premixed ◽  
Fuel Evaporation

Liquid fuel evaporation was investigated in a premix duct, operating at conditions expected for lean premixed and prevaporized combustion. Results from a flat prefilming airblast atomizer are presented. Kerosine Jet A was used in all experiments. Air pressure, air temperature and liquid fuel flow rate were varied separately, their relative influences on atomization, evaporation and fuel dispersion are discussed. The results show, that at pressures up to 15 bars and temperatures up to 850 K, nearly complete evaporation of the fuel was achieved, without autoignition of the fuel. For the configuration tested, the fuel distributions of the liquid and evaporated fuel sbow very little differences in their dispersion characteristics and were not much affected by a variation of the operating conditions.

scholarly journals Molten Salt Reactors

2021 ◽  
Author(s):  
Thomas Dolan
Keyword(s):  
Molten Salt ◽  
Nuclear Power ◽  
Liquid Fuel ◽  
Fission Products ◽  
Processing Plant ◽  
Fast Reactors ◽  
Melting Temperatures ◽  
Load Following ◽  
Reactor Types ◽  
Reactor Accidents

<p><br></p> <div> <table> <tr> <td> <p>Molten Salt Reactors</p> </td> </tr> </table> </div> <br> <div> <table> <tr> <td> <p>© Thomas J. Dolan, Member, IEEE 2021</p> </td> </tr> </table> </div> <br> <p><i>Abstract</i>— Nuclear power is advancing slowly because of public concerns about nuclear accidents, radioactive waste, fuel supply, cost, and nuclear proliferation. The development of molten salt reactors could alleviate most of these concerns and prevent water-cooled reactor accidents like those at Three Mile Island, Chernobyl, and Fukushima. The purpose of this article is to provide information about the potential advantages and problems of molten salt reactors. The coolants could be either <i>fluorides</i> or <i>chlorides</i>, operated above their melting temperatures, to avoid solidification, and well below their boiling temperatures, to prevent evaporation losses. “Fast” reactors use energetic fission neutrons, while “thermal” reactors use graphite to slow the neutrons down to thermal energies. We describe four reactor types: solid fuel thermal, liquid fuel thermal, liquid fuel fast, and “stable salt” fast reactors (liquid fuel in tubes). We discuss load following, reactor design projects, and development problems. Liquid fuel reactors will require a chemical processing plant to adjust fissile fuel inventory, fission products, actinides, and corrosivity in a hot, highly-radioactive environment. </p>

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