Experimental Investigation of Nanotubes Utilization as a Nuclear Fuel Matrix Additive

Author(s):  
Jan Varmuza ◽  
Karel Katovsky ◽  
Jiri Skalicka ◽  
Stepan Foral ◽  
Jitka Matejkova

Great operational challenges are placed on nuclear power plants. These challenges are usually reflected in the expansion of fuel cycle length, long-time operation or power uprates. The one way is to optimize the equipment or replace it with equipment with higher efficiency. The second way is to optimize the fuel and its cladding. In this area it is possible to work mainly on the development of new materials which have better nuclear or mechanical properties. Nuclear power industry is a conservative one. It is necessary to have a detailed knowledge of materials properties of used equipment. Knowledge of the materials behavior is particularly required in the environment where the materials are exposed to neutron flux. This article focuses on new promising materials that can be used in a nuclear fuel, a nuclear reactor or its closest vicinity. Carbon nano materials can be included among these types of materials. Composite materials have generally improved mechanical and thermal properties with addition of nanoparticles. However the additives itself have an impact on the behavior of the neutron field. This article describes an experiment that examined the behavior of neutrons in carbon nano fibers, carbon nano tubes and nano wires of aluminum oxide. The main goal of the experiment was to determine how neutron scattering is affected, when the sample is exposed to neutron beam. The article presents results, including additional testing of nano materials. Additional tests were carried out to verify the purity and parameters of the investigated samples.

2018 ◽  
Vol 4 (2) ◽  
pp. 119-125
Author(s):  
Vadim Naumov ◽  
Sergey Gusak ◽  
Andrey Naumov

The purpose of the present study is the investigation of mass composition of long-lived radionuclides accumulated in the fuel cycle of small nuclear power plants (SNPP) as well as long-lived radioactivity of spent fuel of such reactors. Analysis was performed of the published data on the projects of SNPP with pressurized water-cooled reactors (LWR) and reactors cooled with Pb-Bi eutectics (SVBR). Information was obtained on the parameters of fuel cycle, design and materials of reactor cores, thermodynamic characteristics of coolants of the primary cooling circuit for reactor facilities of different types. Mathematical models of fuel cycles of the cores of reactors of ABV, KLT-40S, RITM-200M, UNITERM, SVBR-10 and SVBR-100 types were developed. The KRATER software was applied for mathematical modeling of the fuel cycles where spatial-energy distribution of neutron flux density is determined within multi-group diffusion approximation and heterogeneity of reactor cores is taken into account using albedo method within the reactor cell model. Calculation studies of kinetics of burnup of isotopes in the initial fuel load (235U, 238U) and accumulation of long-lived fission products (85Kr, 90Sr, 137Cs, 151Sm) and actinoids (238,239,240,241,242Pu, 236U, 237Np, 241Am, 244Cm) in the cores of the examined SNPP reactor facilities were performed. The obtained information allowed estimating radiation characteristics of irradiated nuclear fuel and implementing comparison of long-lived radioactivity of spent reactor fuel of the SNPPs under study and of their prototypes (nuclear propulsion reactors). The comparison performed allowed formulating the conclusion on the possibility in principle (from the viewpoint of radiation safety) of application of SNF handling technology used in prototype reactors in the transportation and technological process layouts of handling SNF of SNPP reactors.


Author(s):  
Marco Ciotti ◽  
Jorge L. Manzano ◽  
Vladimir Kuznetsov ◽  
Galina Fesenko ◽  
Luisa Ferroni ◽  
...  

Financial aspects, environmental concerns and non-favorable public opinion are strongly conditioning the deployment of new Nuclear Energy Systems across Europe. Nevertheless, new possibilities are emerging to render competitive electricity from Nuclear Power Plants (NPPs) owing to two factors: the first one, which is the fast growth of High Voltage lines interconnecting the European countries’ national electrical grids, this process being triggered by huge increase of the installed intermittent renewable electricity sources (Wind and PV); and the second one, determined by the carbon-free constraints imposed on the base load electricity generation. The countries that due to public opinion pressure can’t build new NPPs on their territory may find it profitable to produce base load nuclear electricity abroad, even at long distances, in order to comply with the European dispositions on the limitation of the CO2 emissions. In this study the benefits from operating at multinational level with the deployment of a fleet of PWRs and subsequently, at a proper time, the one of Lead Fast Reactors (LFRs) are analyzed. The analysis performed involves Italy (a country with a current moratorium on nuclear power on spite that its biggest utility operates NPPs abroad), and the countries from South East and Central East Europe potentially looking for introduction or expansion of their nuclear power programmes. According to the predicted evolution of their Gross Domestic Product (GDP) a forecast of the electricity consumption evolution for the present century is derived with the assumption that a certain fraction of it will be covered by nuclear electricity. In this context, evaluated are material balances for the front and the back end of nuclear fuel cycle associated with the installed nuclear capacity. A key element of the analysis is the particular type of LFR assumed in the scenario, characterized by having a fuel cycle where only fission products and the reprocessing losses are sent for disposition and natural or depleted uranium is added to fuel in each reprocessing cycle. Such LFR could be referred to as “adiabatic reactor”. Owing to introduction of such reactors a substantive reduction in uranium consumption and final disposal requirements can be achieved. Finally, the impacts of the LFR and the economy of scale in nuclear fuel cycle on the Levelized Cost of Electricity (LCOE) are being evaluated, for scaling up from a national to a multinational dimension, illustrating the benefits potentially achievable through cooperation among countries.


Author(s):  
Akbar Abbasi

Nuclear power plants to generates electric energy used nuclear fuel such as Uranium Oxide (UOX). A typical VVER−1000 reactor uses about 20–25 tons of spent fuel per year. The fuel transmutation of UOX fuel was evaluated by VISTA computer code. In this estimation the front end and back end components of fuel cycle was calculated. The front end of the cycle parameter are FF requirements, enrichment value requirements, depleted uranium amount, conversion requirements and natural uranium requirements. The back-end component is Spent Fuel (SF), Actinide Inventory (AI) and Fission Product (FP) radioisotopes.


2017 ◽  
Vol 2017 ◽  
pp. 1-17
Author(s):  
Muhammad Minhaj Khan ◽  
Jae Min Lee ◽  
Jae Hak Cheong ◽  
Joo Ho Whang

With a view to providing supportive information for the decision-making on the direction of the future nuclear energy systems in Korea (i.e., direct disposal or recycling of spent nuclear fuel) to be made around 2020, quantitative studies on the spent nuclear fuel (SNF) including transuranic elements (TRUs) and a series of economic analyses were conducted. At first, the total isotopic inventory of TRUs in the SNF to be generated from all thirty-six units of nuclear power plants in operation or under planning is estimated based on the Korean government’s official plan for nuclear power development. Secondly, the optimized deployment strategies are proposed considering the minimum number of sodium cooled-fast reactors (SFRs) needed to transmute all TRUs. Finally, direct disposal and Pyro-SFR closed nuclear energy systems were compared using equilibrium economic model and considering reduction of TRUs and electricity generation as benefits. Probabilistic economic analysis shows that the assumed total generation cost for direct disposal and Pyro-SFR closed nuclear energy systems resides within the range of 13.60~33.94 mills/kWh and 11.40~25.91 mills/kWh, respectively. Dominant cost elements and the range of SFR overnight cost which guarantees the economic feasibility of the Pyro-SFR closed nuclear energy system over the direct disposal option were also identified through sensitivity analysis and break-even cost estimation.


Author(s):  
Je´roˆme Galtier

For 45 years TN International has been involved in the radioactive materials transportation field. Since the beginning the spent nuclear fuel transportation has been its core business. During all these years TN International, now part of AREVA, has been able to anticipate and fulfill the needs for new transport or storage casks designed to fit the nuclear industry evolutions. A whole fleet of casks able to transport all the materials of the nuclear fuel cycle has been developed. In this presentation we will focus on the casks used to transport the fresh and used MOX fuel. To transport the fresh MOX BWR and PWR fuel, TN International has developed two designs of casks: the MX 6 and the MX 8. These casks are and have been used to transport MOX fuel for French, German, Swiss and in a near future Japanese nuclear power plants. A complete set of baskets have been developed to optimize the loading in terms of integrated dose and also of course capacity. MOX used fuel has now its dedicated cask: the TN112 which certificate of approval has been obtained in July 2008. This cask is able to transport 12 MOX spent fuel elements with a short cooling time. The first loading of the cask has been performed in September 2008 in the EDF nuclear power plant of Saint-Laurent-des-Eaux. By its continuous involvement in the nuclear transportation field, TN International has been able to face the many challenges linked to the radioactive materials transportation especially talking of MOX fuel. TN International will also have to face the increasing demand linked to the nuclear renaissance.


2020 ◽  
Vol 225 ◽  
pp. 03002
Author(s):  
O.V. Maslov ◽  
V.A. Mokritskiy ◽  
A.V. Sokolov

The task of determining the initial enrichment of nuclear fuel (NF) at nuclear power plants in real time is relevant for both economic indicators of operation of the power unit and for all components of nuclear safety (nuclear safety, security and safeguards). The technology used by nuclear fuel cycle companies is not suitable for use at nuclear power plants. It is proposed to use a measuring system based on CdZnTe semiconductor detectors designed to control the burn-up depth of nuclear fuel for estimating the initial enrichment of fresh nuclear fuel in fuel assemblies (FA). The initial enrichment is estimated with help of the gamma radiation of uranium isotopes of fresh nuclear fuel. A distinctive feature of the system that has been developed is the use of passive tomography technology to take into account the self-absorption of radiation in the FA. The promise of the proposed method for estimating initial enrichment is confirmed by experimental measurements and simulation results. It is shown that the system developed makes it possible to determine the enrichment of nuclear fuel, taking into account its profiling by the volume of FA. Also, the results of measurements confirmed the possibility of using the proposed technical solutions for CdZnTe detectors to create portable monitoring systems for special nuclear material in the field. The solution of this task is of great importance for national security.


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