Impact of Resonance Treatment on Minor Actinide Incineration in a D–T Thorium Fusion Concept

Resonance treatments have an essential role to reliable neutronic calculations with different neutronic parameters. In this study presents the effect of resonance treatment and various tritium breeder materials on the incineration of the nitride fuels containing minor actinide mixed thoria in the Deuterium–Tritium fusion driven hybrid reactor as time dependent. Neutron transport calculations under resonance treatment and without resonance treatment are performed by using XSDRNPM/SCALE 5 codes. The impact of resonance treatments and various tritium breeder materials on tritium breeding, energy multiplication, total fission rate (∑_f), cumulative fissile fuel enrichment, fissile fuel breeding, average burn up values are comparatively investigated. It is observed that the neutronic results affect from both resonance treatment and the tritium breeder materials as time dependent.     

Effect of Fusion Neutron Source Numerical Models on Neutron Wall Loading in a D—D Tokamak Device

Effect of various spatial and energy distributions of fusion neutron source on the calculation of neutron wall loading of Tokamak D-D fusion device has been investigated by means of the 3-D Monte Carlo code MCNP.A realistic Monte Carlo source model was developed based on the accurate representation of the spatial distribution and energy spectrum of fusion neutrons to solve the complicated problem of tokamak fusion neutron source modelling.The results show that those simplified source models will introduce significant uncertainties.For accurate estimation of the key nuclear responses of the tokamak design and analyses,the use of the realistic source is recommended.In addition,the accumulation of tritium produced during D-D plasma operation should be carefully considered.     

Numerical Study on Effects of Fuel Mixture Fraction and Li-6 Enrichment on Neutronic Parameters of a Fusion–Fission Hybrid Reactor

This study presents the effects of mixture fractions of nuclear fuels (mixture of fissile–fertile fuels and mixture of two different fertile fuels) and ⁶Li enrichment on the neutronic parameters (the tritium breeding ratio, TBR, the fission rate, FR, the energy multiplication ratio, M, the fissile breeding rate, FBR, the neutron leakage out of blanket, L, and the peak-to-average fission power density ratio, Γ) of a deuterium–tritium (D–T) fusion neutron-driven hybrid blanket. Three different fertile fuels (²³²Th, ²³⁸U and ²⁴⁴Cm), and one fissile fuel (²³⁵U) were selected as the nuclear fuel. Two different coolants (pressurized helium and natural lithium) were used for the nuclear heat transfer out of the fuel zone (FZ). The Boltzmann transport equation was solved numerically for obtaining the neutronic parameters with the help of the neutron transport code XSDRNPM/SCALE4.4a. In addition, these calculations were performed by also using the MCNP4B code. The sub-limits of the mixture fractions and ⁶Li enrichment were determined for the tritium self-sufficiency. The considered hybrid reactor can be operated in a self-sufficiency mode in the cases with the fuel mixtures mixed with a fraction of equal to or greater than these sub-limits. Furthermore, the numerical results show that the fissile fuel breeding and fission potentials of the blankets with the helium coolant are higher than with the lithium coolant.     

Film Boiling in Presence of a Magnetic Field in Liquid Metals Within Framework of Taylor–Helmholtz Instabilities in Application to Fusion Reactor Project

From a consideration of a model for the development of magnetohydrodynamics perturbation at the interface during film boiling on a liquid metal in presence of a magnetic field, an analytical expression for the effect of a magnetic field was derived. The predictions within Taylor–Helmholtz model disagree with the available experimental measurements made on mercury, where for high magnetic field where a vapor layer is expected the frequency bubble departure frequency decreases contrary to the invariable theoretical value predicted.     

Nuclear Data Sheets for A = 251–259 (odd)

The evaluators present in this publication spectroscopic data and level schemes from radioactive decay and nuclear reaction studies for all known nuclei with mass numbers A = 251, 253, 255, 257, and 259.     

Determination of Thermomagnetic Current by Using Neutron Released from Deuterium–Tritium Fusion Reactions in Hybrid Reactors

It is proposed to use the neutrons released from a Deuterium–Tritium fusion reaction to drive thermomagnetic currents in a plasma corona surrounding the fusion plasma through the heating of the corona with nuclear reactions by the neutrons released in the fusion reaction because the fusion reaction cross sections are larger for slow neutrons, it is proposed to slow them down in a moderator separated from the hot plasma of the corona, giving the configuration a similarity to a heterogeneous nuclear fission reactor. While in a fission reactor the separation makes possible a growing neutron chain reaction, it here makes possible the autocatalytic amplification of the thermomagnetic currents by an increase of the fusion reaction rate through a rise of the plasma pressure by the magnetic pressure of the thermomagnetic currents. This is expected to substantially increase the product nτ over its Lawson value.     

Evaluation of Complete Neutron Nuclear Data for~(58,60,61,62,64,Nat)Ni

Introduction Ni is a very important structure material in nuclear fusion engineering. The natural nickel consists of five stable isotopes. The neutron nuclear data were evaluated for ~(58,60,61,62,64,Nat)Ni in the energy range 10~(-5) eV to 20 MeV. The data includes total, elastic, non-elastic, total inelastic, inelastic cross sections to 33     

Use of Refractory Coatings in Systems for Melt Containment in a Serious Accident at a Nuclear Power Plant with a VVÉR Reactor

A computational analysis is performed of the use of zirconium dioxide ceramic in melt containment systems with relatively thin heat-conducting structures. The results of an investigation of the physicochemical processes for the interaction of melt with zirconium dioxide ceramic are presented. It is shown that the use of zirconium dioxide ceramic together with a passive water source gives the required melt cooling parameters for 3 to 24 h depending on the cooling regime. 4 figures, 9 references.     

Reevaluation of Neutron Nuclear Data of ~(98,100)Mo in the energy region 0.1～20 MeV

IntroductionFortheelementmolybdenum,therearesevenstableisotopes:Mo(14.84%),Mo(9.25%),Mo929495(15.92%),96Mo(16.68%),97Mo(9.55%),98Mo(24.13%)and100Mo(9.63%),whichareimportantfissionproducts,alsoratherimportantstructurematerialnuclei.Thispaperonlyrefersto98Moand100Mo,theexistedevaluationfilesincludeENDF/B-6,JEF-2,JENDL-3.2andCENDL-3.However,theevaluationfilesinENDF/B-6(1980)onlyinclude(n,γ)data(MT=102infile3,8,9).ThepresentresultswereonlycomparedwithJEF-2,JENDL-3.2andCENDL-3an…     

The Sub-Library of Nuclear Level Density —The Data File of Nuclear Level Density Parameters (CENPL.LDP)

One of the basic statistical properties of the excited nuclear levels is the nuclear level density, which are a crucial ingredient in the nuclear reaction models and neutron transport calculations. For example, the level densities are needed in the calculations of the widths, cross sections, spectra etc. for various reaction channels, and the requirements of their accuracy and reliability are ever higher     

Ultra-Dense Hydrogen H(−1) as the Cause of Instabilities in Laser Compression-Based Nuclear Fusion

Ultra-dense hydrogen H(?1) is a quantum material and the first material which is superfluid and superconductive at room temperature. This has been shown in detail for the deuterium form D(?1). With its experimentally determined H–H bond distance of normally 2.3 ± 0.1 pm, it is up to a factor of 10⁵ denser than hydrogen ice composed of H₂ molecules. Its existence means that when hydrogen is compressed to high temperature and density, as in laser-induced nuclear inertial-confinement fusion (ICF), sudden localized spontaneous transitions to H(?1) will give spots in the material where pressure falls strongly. Such pressure drops give a non-homogeneous phase which will not ignite smoothly. The energy released by the rapid transition to H(?1) will further cause non-isotropic motion of the target material. We here propose that the instability problems which plague ICF can be circumvented by using ultra-dense hydrogen H(?1) directly as the fusion fuel.     

Tritium depth profiling in surface regions of solids by use of the T(d, α)n reaction

Tritium depth profiling with an incident deuteron beam by use of the T(d, α)n reaction was studied for the case where the energy spectrum of the emitted α-particles is used to evaluate the depth profile. Appropriate probing energies were considered to be from 100 keV to 1 MeV. The characteristics of this method were evaluated for a variety of experimental measurement conditions. The method was demonstrated for thin titanium layers containing tritium at probing energies of about 600 keV. The distribution of tritium obtained were almost uniform with depth, as expected, and the measured tritium content agreed well with that nominally stated.     

Effect of Rotational Transform on Thermal Transport in Stellarator–Heliotron Plasmas on LHD

Experimental evidence that indicates a positive effect of rotational transform on thermal transport has been shown for electron cyclotron heated plasmas on large helical device (LHD). Although this positive dependence was suggested by earlier scaling studies on energy confinement time, there was a concern that rotational transform is strongly correlated with another major non-dimensional parameter, that is, aspect ratio, in stellarator–heliotron systems. A careful experiment to exclude correlation between these two non-dimensional parameters was carried out on LHD by means of combining helical coil pitch control and limiter insertion. Plasmas with similar aspect ratio but different rotational transform have been compared in terms of global energy confinement time and local heat diffusivity. Energy confinement time increases with the rotational transform. Also the comparison of plasmas dimensionally similar in terms of normalized gyro-radius, collisionality, normalized pressure and aspect ratio has indicated that thermal transport improves with rotational transform. Since the plasmas studied here are dominated by turbulent transport rather than neoclassical transport, the identified feature, common to toroidal plasmas with tokamak, will stimulate the challenge to resolve the origin of the favorable effect of poloidal field and the compatibility with drift turbulence theory.     

Estimate of the Efficiency of Hydrogen–Metal Hydride (Intermetallic Compound) Systems in the Separation of the Three-Isotope Mixtures H–D–T

A method is developed for calculating apparatus for separating a three-isotope mixture H–D–T by the sorption method using hydrides of metals or intermetallic compounds. Relations are established between the partition coefficients and mass-transfer characteristics, determined for binary isotopic mixtures of hydrogen, and the parameters determining the isotopic equilibrium and the kinetics of mass transfer in the system gas–solid hydride phase with three isotopes. The efficiencies of various sorbents for deprotization of deuterium–tritium mixture are compared. 4 figures, 2 tables, 7 references.     

Effect of inorganic salts on Se(Ⅳ) and Re(Ⅶ) diffusions in bentonite

Diffusion behaviors of Se(IV) and Re(VII) in bentonite were investigated by a through-diffusion method in nitrate, sulfate, carbonate and silicate solutions. SEM-EDS analysis showed that Se(IV) was reduced to red precipitate Se(0) by sulfite. Se(IV) was sorbed on bentonite with distribution coefficient Kd of(2.6–5.3)×10-4m3/kg in sulfite, nitrate and sulfate solutions, whereas it was hardly sorbed in carbonate and silicate solutions. The effective diffusion coefficients were De =(0.81–7.0)×10-11m2/s for Se(IV) and De =(1.4–4.4)×10-11m2/s for Re(VII). The De value of Se(IV) exhibited a dependence on the inorganic salts in the order of sulfite ≈ nitrate ≈ sulfate silicate carbonate, whereas the salts had insignificant effect on Re(VII) diffusion. The results suggest that the discrepancy in diffusion mechanism may lead to the different impact of the salts on the diffusion of Se(IV) and Re(VII) in GMZ bentonite.     

Effect of Energy Conservation on In-medium NN→NΔ Cross Section in Isospin-asymmetric Nuclear Matter

正The in-medium NN→NΔ cross section is one of the key ingredients for theπ→N→Δloop in the simulations because it will directly influence the first Δ production which can decay into nucleon and pion or rescatter with nucleons.Most of the transport codes adopted the free space NN→     

Effect of steam quality on two-phase flow in a natural circulation loop

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