scholarly journals Extension of lifespan of graphite in fuel blocks of high-temperature gas-cooled reactors as the resource for ensuring design values of nuclear fuel burn-up

2019 ◽  
Vol 2019 (3) ◽  
pp. 40-52
Author(s):  
Olga Igorevna Bulakh ◽  
Oleg Konstantinovich Kostylev ◽  
Vladimir Nikolaevich Nesterov ◽  
Eldar Koshalievich Cherdizov
Keyword(s):  
High Temperature ◽  
Nuclear Fuel ◽  
Fuel Burn ◽  
Design Values ◽  
High Temperature Gas

scholarly journals Design of the Online Gross γ Monitoring Instrument at the Exit of the Helium Purification System in HTR-PM

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Mengqi Lou ◽  
Liguo Zhang ◽  
Feng Xie ◽  
Jianzhu Cao ◽  
Jiejuan Tong ◽  
...  
Keyword(s):  
High Temperature ◽  
Detection Efficiency ◽  
Primary Circuit ◽  
Source Terms ◽  
Primary Loop ◽  
Monitoring Instrument ◽  
Purification System ◽  
Design Values ◽  
Under Construction ◽  
High Temperature Gas

After the successful construction and operation experience of the 10 MW high-temperature gas-cooled reactor (HTR-10), a high-temperature gas-cooled pebble-bed modular (HTR-PM) demonstration plant is under construction in Shidao Bay, Rongcheng City, Shandong province, China. An online gross γ monitoring instrument has been designed and placed at the exit of the helium purification system (HPS) of HTR-PM and is used to detect the activity concentration in the primary circuit after purification. The source terms in the primary loop of HTR-PM and the helium purification process were described. The detailed configuration of the gross γ monitoring instrument was presented in detail. The Monte Carlo method was used to simulate the detection efficiency of the monitoring system. Since the actual source terms in the primary loop of HTR-PM may be different than the current design values, a sensitivity analysis of the detection efficiency was implemented based on different relative proportions of the nuclides. The accuracy and resolution of the NaI(Tl) detector were discussed as well.

scholarly journals Development of Analytical Procedures for Chemical Characterization of Substrates for the Production of TRISO Coated Particles as Nuclear Fuel in High Temperature Gas-Cooled Reactors

2020 ◽  
Vol 12 (17) ◽  
pp. 7221
Author(s):  
Ewelina Chajduk ◽  
Paweł Kalbarczyk ◽  
Jakub Dudek ◽  
Marta Pyszynska ◽  
Anna Bojanowska-Czajka ◽  
...  
Keyword(s):  
High Temperature ◽  
Nuclear Fuel ◽  
Inductively Coupled Plasma ◽  
Chemical Characterization ◽  
Quantitative Chemical Analysis ◽  
Coated Particles ◽  
Icp Ms ◽  
Analytical Procedures ◽  
High Temperature Gas

High temperature gas-cooled reactors have recently gained importance as a source of electricity and process heat. Nuclear fuel used in these reactors consists of TRISO (TRiple coated ISOtropic) coated particles, where spherical grains of UO2 or UC2 or UCO kernel are covered with four successive layers consisting of pyrolytic carbon and silicon carbide. Of great importance is the chemical purity of reagents and substances used for the production of TRISO coated fuel particles. Analytical techniques ensuring the determination of elements at trace levels are inductively coupled plasma mass spectrometry (ICP-MS) and neutron activation analysis (NAA). They were applied in this work for the chemical characterization of substrates used for TRISO fuel production. Two analytical procedures were developed: the first, where materials are analyzed using ICP-MS, and the second with the aid of NAA. Successive stages of these procedures are described with details. Results of quantitative chemical analysis of examined substances are reported as well as detection limits for the investigated elements. Moreover, the expanded uncertainties estimated for the determined elements while employing the devised analytical procedures are presented.

Influence of the Graphite’s Lifespan on the Design Value of Fuel Burnup in High Temperature Gas-Cooled Reactors

2015 ◽  
Vol 1084 ◽  
pp. 313-316
Author(s):  
Denis F. Baybakov ◽  
Aleksey V. Golovatsky ◽  
Artem G. Naymushin ◽  
Vladimir N. Nesterov ◽  
Savva N. Savanyuk ◽  
...  
Keyword(s):  
High Temperature ◽  
Nuclear Fuel ◽  
Reactor Core ◽  
Fuel Burnup ◽  
Axial Distribution ◽  
Design Value ◽  
Helium Coolant ◽  
High Temperature Gas

This paper describes a method of determining the correlation of the exhausted graphite fuel blocks’ lifespan in high temperature gas-cooled reactors with the fuel burnup. The axial distribution of the local values of the exhausted lifespan of graphite fuel blocks was obtained. It is shown that for ensuring the compliance of the design value of the fuel burnup with graphite fuel blocks operability, it is necessary to reduce the average mixed temperature of the helium coolant leaving the reactor core and as well as reduce the time between nuclear fuel recharges.

scholarly journals Extension of lifespan of graphite in fuel blocks of high-temperature gas-cooled reactors as the resource for ensuring design values of nuclear fuel burn-up

2019 ◽  
Vol 5 (4) ◽  
pp. 289-295 ◽  
Author(s):  
Olga I. Bulakh ◽  
Oleg K. Kostylev ◽  
Vladimir N. Nesterov ◽  
Eldar K. Cherdizov
Keyword(s):  
High Temperature ◽  
Nuclear Fuel ◽  
Alternative Energy ◽  
Fuel Cycle ◽  
Reactor Core ◽  
Calculated Data ◽  
Fuel Burnup ◽  
The Core ◽  
High Temperature Reactors ◽  
High Temperature Gas

High-temperature gas-cooled reactor (HTGR) is one of promising candidates for new generation of nuclear power reactors. This type of nuclear reactor is characterized with the following principal features: highly efficient generation of electricity (thermal efficiency of about 50%); the use of high-temperature heat in different production processes; reactor core self-protection properties; practical exclusion of reactor core meltdown in case of accidents; the possibility of implementation of various nuclear fuel cycle options; reduced radiation and thermal effects on the environment, forecasted acceptability of financial performance with respect to cost of electricity as compared with alternative energy sources. The range of output coolant temperatures in high-temperature reactors within the limits of 750–950 °C predetermines the use of graphite as the structural material of the reactor core and helium as the inert coolant. Application of graphite ensures higher heat capacity of the reactor core and its practical non-meltability. Residence time of reactor graphite depends on the critical value of fluence of damaging neutrons (neutrons with energies above 180 keV). In its turn, the value of critical neutron fluence is determined by the irradiation temperature and flux density of accompanying gamma-radiation. The values of critical fluence for graphite decrease within high-temperature region of 800–1000 °C to 1·1022 – 2·1021 cm–2, respectively. The compactness of the core results in the increase of the fracture of damaging neutrons in the total flux. These circumstances predetermine relatively low values of lifespan of graphite structures in high-temperature reactors. Design features and operational parameters of GT-MHR high-temperature gas-cooled reactor are described in the present paper. Results of neutronics calculations allowing determining the values of damaging neutron flux, nuclear fuel burnup and expired lifespan of graphite of fuel blocks were obtained. The mismatch between positions of the maxima in the dependences of fuel burnup and exhausted lifespan of graphite in fuel blocks along the core height is demonstrated. The map and methodology for re-shuffling fuel blocks of the GT-MHR reactor core were developed as the result of analysis of the calculated data for ensuring the matching between the design value of the fuel burnup and expected total graphite lifespan.

Energy in the 1980s - Natural sources of nuclear fuel

1974 ◽  
Vol 276 (1261) ◽  
pp. 495-505 ◽  
Keyword(s):  
High Temperature ◽  
Nuclear Fuel ◽  
World Wide ◽  
Low Cost ◽  
Good Time ◽  
Natural Sources ◽  
Refining Plant ◽  
Ore Bodies ◽  
Price Range ◽  
High Temperature Gas

Reserves, resources, potential resources (or potential) are defined and related to price categories and it is deduced that sufficient uranium is available from reserves (866 000 tonnes U) at a price of less than $20/kg U 3 O g to meet estimated demands to the end of the 1970s. However, this will mean rehabilitating mines that have shut down and commissioning new or regenerating old refining plant. There is a risk of a shortage of uranium by the mid 1980s if safeguards are not taken in time to ensure that uranium can be made available from reserves and estimated additional resources (916000 t U) in the < $20/kg U 3 O g price category presently indicated as being in the ground. Resources in the price range $20-30/kg U 3 O g are over 10 6 t U and in the $30-60/kg U 3 O g are of the same order or more. It is considered that prospecting on a world-wide basis should be increased appreciably and maintained at a reasonable level. Also, that new search techniques should be developed and applied mainly to the discovery of hidden ore-bodies. If this is done in good time, there is no reason to predict any absolute shortage of relatively low-cost uranium this century. Thorium has a potential in high-temperature gas-cooled reactors. Currently known resources are of the order of 10 6 t ThO 2*

An Environmental Wet Cell For High Voltage Electron Microscopy

1973 ◽  
Vol 31 ◽  
pp. 18-19
Author(s):  
N.J. Tighe ◽  
H.M. Flower ◽  
P.R. Swann
Keyword(s):  
Electron Microscopy ◽  
High Temperature ◽  
Image Quality ◽  
Inelastic Scattering ◽  
High Voltage ◽  
High Voltage Electron Microscopy ◽  
Voltage Electron ◽  
Environmental Cell ◽  
Water Saturated ◽  
High Temperature Gas

A differentially pumped environmental cell has been developed for use in the AEI EM7 million volt microscope. In the initial version the column of gas traversed by the beam was 5.5mm. This permited inclusion of a tilting hot stage in the cell for investigating high temperature gas-specimen reactions. In order to examine specimens in the wet state it was found that a pressure of approximately 400 torr of water saturated helium was needed around the specimen to prevent dehydration. Inelastic scattering by the water resulted in a sharp loss of image quality. Therefore a modified cell with an ‘airgap’ of only 1.5mm has been constructed. The shorter electron path through the gas permits examination of specimens at the necessary pressure of moist helium; the specimen can still be tilted about the side entry rod axis by ±7°C to obtain stereopairs.

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