scholarly journals Measurement of the spatial-energy distribution of neutrons in the irradiation channel of the critical facility

2022 ◽  
Vol 2155 (1) ◽  
pp. 012021
Author(s):  
M T Aitkulov ◽  
D S Dyussambayev ◽  
N K Romanova ◽  
Sh H Gizatulin ◽  
A A Shaimerdenov ◽  
...  
Keyword(s):  
Energy Distribution ◽  
Neutron Flux ◽  
Nuclear Physics ◽  
Critical Assembly ◽  
State Enterprise ◽  
Fast Neutrons ◽  
Thermal Neutrons ◽  
Irradiation Channel ◽  
Axial Distribution ◽  
The Core

Abstract One of the basic installations of the Republican State Enterprise “Institute of Nuclear Physics” of the Ministry of Energy of the Republic of Kazakhstan is a critical assembly, which is a zero-power reactor. Desalinated water and beryllium serve as moderators and neutrons reflectors. The energy spectrum of neutrons in the core is thermal. The main purpose and area of application is the modeling and study of the neutronic characteristics of the cores of water-moderated research reactors of various types. The paper presents the results of experimental measurements of the spatial-energy distribution of neutrons in the dry, central channel of the critical assembly. Measurements of the neutron flux were carried out using activation foils for three energy groups of neutrons: thermal, epithermal, and fast. The measured thermal neutrons flux in the irradiation channel is ~ 3·108 cm‒2s‒1, and fast neutrons flux (with energies above 0.7 MeV) is ~ 8·108 cm‒2s‒1. The fraction of thermal neutrons in the integral flux was 0.23%, and the fraction of fast neutrons was 0.62%. In the axial distribution of thermal and fast neutrons, the maximum value of the neutron flux is 50 mm below the midplane of the core.

Nuclear Instrumentation Systems in Prototype Fast Breeder Reactor

2004 ◽  
Author(s):  
P. M. Vijayakumaran ◽  
C. P. Nagaraj ◽  
C. Paramasivan Pillai ◽  
R. Ramakrishnan ◽  
M. Sivaramakrishna
Keyword(s):  
Neutron Flux ◽  
Early Warning System ◽  
Warning System ◽  
Radiation Monitoring ◽  
Fast Breeder Reactor ◽  
Delayed Neutrons ◽  
The Core ◽  
Flux Monitoring ◽  
Nuclear Instrumentation ◽  
Fission Chambers

The nuclear instrumentation systems of the Prototype Fast Breeder Reactor (PFBR) primarily comprise of global Neutron Flux Monitoring, Failed Fuel Detection & Location, Radiation Monitoring and Post-Accident Monitoring. High temperature fission chambers are provided at in-vessel locations for monitoring neutron flux. Failed fuel detection and location is by monitoring the cover gas for fission gases and primary sodium for delayed neutrons. Signals of the core monitoring detectors are used to initiate SCRAM to protect the reactor from various postulated initiating events. Radiation levels in all potentially radioactive areas are monitored to act as an early warning system to keep the release of radioactivity to the environment and exposure to personnel well below the permissible limits. Fission Chambers and Gamma Ionisation Chambers are located in the reactor vault concrete for monitoring the neutron flux and gamma radiation levels during and after an accident.

Calculation studies of coated particles performance in sodium-cooled fast reactor

Kerntechnik ◽  
2021 ◽  
Vol 86 (1) ◽  
pp. 45-49
Author(s):  
N. V. Maslov ◽  
E. I. Grishanin ◽  
P. N. Alekseev
Keyword(s):  
Fast Reactor ◽  
Reactor Core ◽  
Heat Removal ◽  
Design Solution ◽  
Fast Neutrons ◽  
Steel Shell ◽  
Primary Circuit ◽  
Coated Particles ◽  
The Core ◽  
Fuel Assemblies

Abstract This paper presents results of calculation studies of the viability of coated particles in the conditions of the reactor core on fast neutrons with sodium cooling, justifying the development of the concept of the reactor BN with microspherical fuel. Traditional rod fuel assemblies with pellet MOX fuel in the core of a fast sodium reactor are directly replaced by fuel assemblies with micro-spherical mixed (U,Pu)C-fuel. Due to the fact that the micro-spherical (U, Pu)C fuel has a developed heat removal surface and that the design solution for the fuel assembly with coated particles is horizontal cooling of the microspherical fuel, the core has additional possibilities of increasing inherent (passive) safety and improve the competitiveness of BN type of reactors. It is obvious from obtained results that the microspherical (U, Pu)C fuel is limited with the maximal burn-up depth of ∼11% of heavy atoms in conditions of the sodium-cooled fast reactor core at the conservative approach; it gives the possibility of reaching stated thermal-hydraulic and neutron-physical characteristics. Such a tolerant fuel makes it less likely that fission products will enter the primary circuit in case of accidents with loss of coolant and the introduction of positive reactivity, since the coating of microspherical fuel withstands higher temperatures than the steel shell of traditional rod-type fuel elements.

scholarly journals High sensitive depleted MOSFET-based neutron dosimetry

2019 ◽  
Vol 18 ◽  
pp. 145
Author(s):  
M. Fragopoulou ◽  
V. Konstantakos ◽  
M. Zamani ◽  
S. Siskos ◽  
T. Laopoulos ◽  
...  
Keyword(s):  
Lithium Fluoride ◽  
Field Effect ◽  
Field Effect Transistor ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Fast Neutrons ◽  
Thermal Neutrons ◽  
Neutron Dosimetry ◽  
Effect Transistor ◽  
The One

A new dosemeter based on a depleted Metal-Oxide-Semiconductor field effect transistor, sensitive to both neutrons and gamma radiation was manufactured at LAAS-CNRS Laboratory, Toulouse France. In order to be used for neutron dosimetry a thin film of lithium fluoride was deposited on the surface of the gate of the device. The characteristics of the dosemeter such as its response to neutron dose were investigated. The response in thermal neutrons was found to be high. In fast neutrons the response was lower than that of thermal neutrons but higher than the one presented in literature.

Determination of the Core Power of a Critical Assembly by Different Methods

Atomic Energy ◽  
2019 ◽  
Vol 125 (4) ◽  
pp. 213-218
Author(s):  
M. A. Sosnin ◽  
A. V. Belin ◽  
A. G. Vasyatkin ◽  
A. A. Molodtsov ◽  
M. A. Kamnev
Keyword(s):  
Critical Assembly ◽  
The Core

scholarly journals Far-Field Plume Characterization of a 100-W Class Hall Thruster

Aerospace ◽  
2020 ◽  
Vol 7 (5) ◽  
pp. 58
Author(s):  
Thibault Hallouin ◽  
Stéphane Mazouffre
Keyword(s):  
Energy Distribution ◽  
Current Density ◽  
Low Voltage ◽  
Ion Current ◽  
Hall Thruster ◽  
Far Field ◽  
Ion Energy ◽  
Ion Energy Distribution ◽  
The Core ◽  
Ion Current Density

The 100 W-class ISCT100-v2 Hall Thruster (HT) has been characterized in terms of far-field plume properties. By means of a Faraday Cup and a Retarding Potential Analyzer, both the ion current density and the ion energy distribution function have been measured over a 180 ∘ circular arc for different operating points. Measurements are compared to far-field plume characterizations performed with higher power Hall thrusters. The ion current density profiles remain unchanged whatever the HT input power, although an asymptotic limit is observed in the core of the plume at high discharge voltages and anode mass flow rates. In like manner, the ion energy distribution functions reveal that most of the beam energy is concentrated in the core of the plume [ − 40 ∘ ; 40 ∘ ] . Moreover, the fraction of low energy ion populations increases at large angles, owing to charge exchange and elastic collisions. Distinct plume regions are identified; they remain similar to the one described for high-power HTs. An efficiency analysis is also performed in terms of current utilization, mass utilization, and voltage utilization. The anode efficiency appears to be essentially affected by a low voltage utilization, the latter originating from the large surface-to-volume ratio inherent to low-power HTs. Experimental results also show that the background pressure clearly affects the plume structure and content.

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