Calculation of Bowing Reactivity of Core Assemblies in Liquid Metal Fast Reactors

2013 ◽  
Author(s):  
Xingkai Huo ◽  
Hong Yu ◽  
Pan Cao ◽  
Li Xu ◽  
Yun Hu ◽  
...  
Keyword(s):  
Liquid Metal ◽  
Large Temperature ◽  
Inherent Safety ◽  
Irradiation Creep ◽  
Fast Reactors ◽  
Small Magnitude ◽  
Analysis System ◽  
Safety Features ◽  
China Experimental Fast Reactor ◽  
Reactivity Change

In liquid-metal-cooled fast reactors, the temperature rise and its gradients over the core region, sometimes with an addition of the accumulated irradiation creep and swelling, result in a radial core expansion and the bowing of subassemblies, both of which lead to the radial displacements of fuel and reflector materials. In spite of the small magnitude of such displacements, the reactivity change due to radial core expansion and bowing of subassemblies during a transient, such as unprotected loss-of-flow (ULOF), is significant in magnitude and plays one of the most important roles among all inherent safety features; the focus is on the change of the power-to-flow ratio (P/F) from 1.0 to 2.0, during which a large temperature gradient is induced. A 3-D code, named PERMOV, is developed for the calculation of such reactivity feedback, at present as a part of the Neutronics Analysis System (NAS); NAS is a 3-D nodal code, independently developed by researchers in China Experimental Fast Reactor; and at the same time, the code PERMOV has a high portability, making it available to run with other mature core physics codes.

scholarly journals Improved FAST Device for Inherent Safety of Oxide-Fueled Sodium-Cooled Fast Reactors

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4610
Author(s):  
Ahmed Amin E. Abdelhameed ◽  
Chihyung Kim ◽  
Yonghee Kim
Keyword(s):  
Operating Temperature ◽  
Reactor Core ◽  
Coolant Temperature ◽  
Inherent Safety ◽  
Oxide Fuel ◽  
Fast Reactors ◽  
Power Oscillation ◽  
Negative Reactivity ◽  
Oscillation Problem ◽  
Reactivity Coefficient

The floating absorber for safety at transient (FAST) was proposed as a solution for the positive coolant temperature coefficient in sodium-cooled fast reactors (SFRs). It is designed to insert negative reactivity in the case of coolant temperature rise or coolant voiding in an inherently passive way. The use of the original FAST design showed effectiveness in protecting the reactor core during some anticipated transients without scram (ATWS) events. However, oscillation behaviors of power due to refloating of the absorber module in FAST were observed during other ATWS events. In this paper, we propose an improved FAST device (iFAST), in which a constraint is imposed on the sinking (insertion) limit of the absorber module in FAST. This provides a simple and effective solution to the power oscillation problem. Here, we focus on an oxide fuel-loaded SFR that is characterized by a more negative Doppler reactivity coefficient and higher operating temperature than the metallic-loaded SFR cores. The study is carried out for the 1000 MWth advanced burner reactor with an oxide fuel-loaded core during postulated ATWS events that are unprotected transient over power, unprotected loss of flow, and unprotected loss of the heat sink. It was found that the iFAST device has promising potentials for protecting the oxide SFR core during the various studied ATWS events.

Suitability of Eutectic Field’s Metal for Use in an Electromagnetohydrodynamically-Enhanced Experimental Two-Phase Flow Loop

2012 ◽  
Author(s):  
A. Lipchitz ◽  
Lilian Laurent ◽  
G. D. Harvel
Keyword(s):  
Liquid Metal ◽  
Two Phase Flow ◽  
Nuclear Reactors ◽  
Liquid Metals ◽  
Metal Flow ◽  
Phase Flow ◽  
Laboratory Setting ◽  
Flow Loop ◽  
Fast Reactors ◽  
Two Phase

Several Generation IV nuclear reactors, such as sodium fast reactors and lead-bismuth fast reactors, use liquid metal as a coolant. In order to better understand and improve the thermal hydraulics of liquid metal cooled GEN IV nuclear reactors liquid metal flow needs to be studied in experimental circulation loops. Experimental circulation loops are often located in a laboratory setting. However, studying liquid metal two phase flow in laboratory settings can be difficult due to the high temperatures and safety hazards involved with traditional liquid metals such as sodium and lead-bismuth. One solution is to use a low melt metal alloy that is as benign as reasonably achievable. Field’s metal is a eutectic alloy of 51% Indium, 32.5% Bismuth and 16.5% Tin by weight and has a melting point of 335K making it ideal for use in a laboratory setting. A study is undertaken to determine its suitability to use in a two-phase experimental flow loop enhanced by magnetohydrodynamic forces. The study investigated its reactivity with air and water, its ability to be influenced by magnetic fields, its ability to flow, and its ease of manufacture. The experiments melted reference samples of Field’s metal and observed its behaviour in a glass beaker, submerged in water and an inclined stainless steel pipe. Then Field’s metal was manufactured in the laboratory and compared to the sample using the same set of experiments and standards. To determine Field’s metal degree of magnetism permanent neodymium magnets were used. Their strength was determined using a Gaussmeter. All experiments were recorded using a COHU digital camera. Image analysis was then performed on the video to determine any movements initiated by the magnetic field forces. In conclusion, Field’s metal is more than suitable for use in experimental settings as it is non-reactive, non-toxic, simple to manufacture, easy to use, and responds to a magnetic force.

Thermal hydraulic challenges of Gas Cooled Fast Reactors with passive safety features

2009 ◽  
Vol 239 (5) ◽  
pp. 840-854 ◽  
Author(s):  
Michael A. Pope ◽  
Jeong Ik Lee ◽  
Pavel Hejzlar ◽  
Michael J. Driscoll
Keyword(s):  
Passive Safety ◽  
Fast Reactors ◽  
Safety Features

Status of District Heating Reactor and its Development Prospects in China

2018 ◽  
Author(s):  
Jing Zhao ◽  
Fei Xie ◽  
Zhihong Liu
Keyword(s):  
Low Temperature ◽  
Nuclear Reactor ◽  
District Heating ◽  
Heating System ◽  
Inherent Safety ◽  
Nuclear Heating Reactor ◽  
New Type ◽  
Nuclear Heating ◽  
Safety Features ◽  
Temperature Heating

Nuclear heating reactor is a new type of power plant that uses nuclear energy as heat source. Low temperature nuclear heating reactor should be the forerunner and main force for developing nuclear heating plant in China. Due to the lower water temperature required by the heating system, this dedicated, non-power generating nuclear reactor works at low temperatures and pressures with inherent safety features. The design, construction and operation of the nuclear heating reactors in various countries in the world were reviewed in this paper, and China’s new demonstration nuclear heating project and NHR-200 low-temperature heating reactor which would be used was discussed in the paper. We put forward the developing route and suggestion for the development of low-temperature heating reactor in China.

Eddy Current Flow Meter Performance in Liquid Metal Flows Inclined to the Sensor Axis

2021 ◽  
Author(s):  
Nico Krauter ◽  
Vladimir Galindo ◽  
Thomas Wondrak ◽  
Sven Eckert ◽  
Gunter Gerbeth
Keyword(s):  
Liquid Metal ◽  
Numerical Simulations ◽  
Eddy Current ◽  
Current Flow ◽  
Fast Reactors ◽  
Flow Meter ◽  
Flow Angle ◽  
Model Experiments ◽  
Inductive Sensor ◽  
Pipe Flows

Abstract The Eddy Current Flow Meter is a reliable and robust inductive sensor for the measurement of flowrates in liquid metal flows. This kind of sensor is usually being used in pipe flows where the flow is mostly parallel to the sensor axis. When this sensor is used as part of the safety instrumentation above the subassemblies in liquid metal cooled fast reactors, the flow angle may change rapidly according to the conditions within the reactor. In this paper we investigate the performance of the Eddy Current Flow Meter in flows inclined to the sensor axis by numerical simulations as well as model experiments. We demonstrate that the Eddy Current Flow Meter yields reliable results for flow angles up to 30° while the sensitivity of the sensor is significantly reduced for larger angles.

Sign in / Sign up

Export Citation Format

Share Document