Development of an Auto-cutting and Sampling Apparatus for Solution Sample

During the separation of short-lived nuclides from fission products, the irradiated sample which is come out by pneumatic tube system will be chemical separated on the base of need. But the first thing is which the sample must be taken out from sample box…     

Progress in Key Technologies of Beijing Neutron–rich Isotope Separation On–line Facility

正1Overview Beijing Neutron-rich Isotope Separation Online Facility(BISOL)is an unstable nuclei beam facility based on China Advanced Research Reactor(CARR).BISOL relies on the use of a U target near the reactor core,in which unstable nuclei are produced by neutron induced fission.The fission products produced in targets are extracted from     

Ub-library of Atomic Masses and Nuclear Ground States Deformations (CENPL.AMD)

The atomic mass is one of basic data of a nuclear. There are the atomic masses in all nuclear reaction model formulas and motion equations. For any reaction calculations atomic masses are basic data for getting binding energies or Q-values. In some applications, it is important also to have atomic masses even for exotic nuclei quite far from the valley of stability. In addition, nuclear ground state deformations and abundance values are also requisite in the nuclear data calculations. For this purpose, A data file on atomic masses and nuclear ground states deformations (AMD) were constructed, which     

Numerical analysis on element creation by nuclear transmutation of fission products

A burnup calculation was performed to analyze the Apr`es ORIENT process, which aims to create highlyvaluable elements from fission products separated from spent nuclear fuels. The basic idea is to use nuclear transmutation induced by a neutron capture reaction followed by a β-decay, thus changing the atomic number Z of a target element in fission products by 1 unit. LWR(PWR) and FBR(MONJU) were considered as the transmutation devices. High rates of creation were obtained in some cases of platinum group metals(44Ru by FBR,46 Pd by LWR) and rare earth(64Gd by LWR,66 Dy by FBR). Therefore, systems based on LWR and FBR have their own advantages depending on target elements. Furthermore, it was found that creation rates of even Z(= Z + 1) elements from odd Z ones were higher than the opposite cases. This creation rate of an element was interpreted in terms of "average 1-group neutron capture cross section of the corresponding target element σc Z defined in this work. General trends of the creation rate of an even(odd) Z element from the corresponding odd(even) Z one were found to be proportional to the 0.78th(0.63th) power of σc Z, however with noticeable dispersion. The difference in the powers in the above analysis was explained by the difference in the number of stable isotopes caused by the even-odd effect of Z.     

Correction to Measurement of Fission Rates of ^235U and ^238u

For the enrichment of fissile nuclide in detecting foils is not so high, the counts of a certain gamma energy （1 596 keV） measured after irradiation would come from the same fission product of the each nuclide （^235U and ^238U）. Consequently the measured value of distribution of fission rate is not precise due to the blending of the nuclide.     

Research of ~(103)Pd Seed Source Preparation

Having very good nuclide properties, 103Pd is an important radioisotope for the use of cancer local treatment (brachytherapy).Using the high puried 103Pd solution, by the way of electroplating, the 103Pd is deposited on the surface of metal bar, then the metal bar coated with 103Pd is sealed in titanium tube. For a seed, the dimensions are φ0.8 mm× 4.5 mm and the typical activity of individual 103Pd seed varies from 18.5-37 MBq. 103Pd seeds by batches can be offered at present and the product is checked out by SDA. Clinical trials have finished in Beijing and Guangzhou,     

Study on SO2 Removal Efficiency by Nanosecond Rising Edge Pulse DBD Under Different Environmental Conditions

In this paper, an experimental study on SO2 removal by nanosecond rising edge pulse dielectric barrier discharge （DBD） plasma, generated by multi-needle-to-plane electrodes, is carried out. The mechanism of the effect of various factors, such as gap size between dielectric barrier and discharge needles, environmental humidity, and inlet speed of gas flow upon the removal efficiency of air purification is analyzed. The studies show that SOs removal efficiency improves with the increase in the gap size between dielectric barrier and discharge needles in the case of a fixed space between two electrodes, and also improves with the increase in the environmental humidity. For a mixed gas with a fixed concentration, there is an optimal inlet speed of gas flow, which leads to the best removal efficiency.     

BAR-MOM Code and Its Application

BAR-MOM code for calculating the height of the fission barrier Bf ,the energy of the ground state is presented; the compound nucleus stability by limit with respect to fission, i.e., the angular momentum (the spin value) Lmax at which the fission barrier disappears, the three principal axis moments of inertia at saddle point for a certain nucleus with atomic number Z, atomic mass number and angular momentum L in units of h for 19相似文献   

High Density Plasma Heating by EC-Waves Injected from the High-Field Side for Mode Conversion to Electron Bernstein Waves in LHD

To realize an excitation of electron Bernstein waves (EBW) via mode conversion from X-mode waves injected from the high magnetic field side (HFS), new inner-vessel mirrors were installed close to a helical coil in the large helical device (LHD). 77 GHz electron cyclotron (EC) wave beams injected from an existing EC-wave injection system toward the new mirror are reflected on the mirror so that the beams are injected to plasmas from HFS. Evident increases in the electron temperature at the plasma core region and the plasma stored energy were observed by the HFS beam injection to the plasmas with the line-average electron density of 7.5×10 19 m 3 , which is slightly higher than the plasma cut-off density of 77 GHz EC-waves, 7.35×10 19 m 3 . The heating efficiency evaluated from the changes in the time derivative of the plasma stored energy reached ～70%. Although so far it is not clear which is the main cause of the heating effect, the mode-converted EBW or the X-mode wave itself injected from the HFS, an effective heating of high-density plasma over the plasma cut-off of EC-wave was successfully demonstrated.     

Structural integrity evaluation of irradiated LEU targets for the production of molybdenum-99 using thermo-mechanical behavior simulation coupled with pressure of fission gas release calculation

Irradiated low-enriched uranium as target plates is used to produce, via neutron radiation and from the molybdenum-99 fission product, technetium-99m, which is a radio-element widely used for diagnosis in the field of nuclear medicine. The behavior of this type of target must be known to prevent eventual failures during radiation. The present study aims to assess,via prediction, the thermal–mechanical behavior, physical integrity, and geometric stability of targets under neutron radiation in a n...     

Separation of ^107pd by Chromatographic Method With DMG Resin

^107pd is a long lived fission product, which is a pure β-emitter with a maximal energy of 33 keV and a fission yield of 0.14%. Present work researches and develops a free-carrier radiochemical separation procedure of ^107pd from mixed fission products in order to meet the requirement of the measurements of nuclear data especially the measurement of its half-life.     

Construction of Covariance Matrix for Absolute Fission Yield Data Measurement

Introduction With the development of reactor physics and computer, now, the covariance data become more and more important in the nuclear engineering applications. For evaluators and experimenters, the information are all given completely only in the case that the covariance matrix is given;because the error, as traditional, is only the diagonal elements of the covariance matrix, describes the accuracy of the data and nothing about the correlation of the data is given. There is the same situation in fission yield data, which are widely used in the radio decay heat calculation, burn-up credit study, radio intensity estimation of fission product and etc.     

Characteristics of Electrode-Water-Electrode Discharge and its Application to Water Treatment

Atmospheric air discharge above the surface of water is an effective method for water treatment.The leakage current and Joule heating of water are reduced by the air gap,which raises the energy efficiency of the water treatment.However,the application of this kind of discharge is limited by a pair of conflicting factors：the chemical efficiency grows as the discharge gap distance decreases,while the spark breakdown voltage decreases as the gap distance decreases.To raise the spark breakdown voltage and the chemical efficiency of atmospheric pressure water surface discharge,both the high-voltage electrode and the ground electrode are suspended above the water surface to form an electrode-water-electrode discharge system.For this system,there are two potential discharge directions：from one electrode to another directly,and from the electrodes to the water surface.The first step in utilizing the electrode-water-electrode discharge is to find out the discharge direction transition criterion.In this paper,the discharge direction transition criterions of spark discharge and streamer discharge are presented.By comparing the discharge characteristics and the chemical efficiencies,the discharge propagating from the electrodes to the water surface is proved to be more suitable for water treatment than that propagating directly between the electrodes.     

Fragment Angular Anisotropies and Inertia Parameters

An analysis of selected fission fragment angular distributions of various target is made using exact theoretical expressions. Theoretical anisotropies obtained from the transition state model are compared with their corresponding values deduced from the statistical scission model. The nuclear moment of inertia extracted from the model calculations are compared with their estimated values from a microscopic theory, which includes the nuclear pairing interactiont. Single particle levels of Nilsson et al. are utilized. It is found that the value of the statistical parameter, is very sensitive to the energy gap parameter, Δ. The reduction of energy gap results in an increase in the moment of inertia. The effect of pairing interaction on the inertia parameters are illustrated and discussed.     

β-decay Study of T_z=-3/2Proton-rich Nucleus ~(29)S

<正>The exotic decay of nuclei far from the stability has recently become a hot topic of nuclear structure research.The nuclide ~(29)S is not well investigated in the A=4n+1,T_z=-3/2series of strong+β-delayed proton precursors.The decay schemes of these nuclei are characterized by     

Study of Relationship Between Neutron Energy and Fission Yields of ~(95)Zr, ~(140)Ba and ~(147)Nd From ~(235)U

This work measures fission yields of 235U induced by neutrons with energy of thermal, 3.0, 5.0, 5.5, 8.0 and 14.8 MeV. The main purpose is to study the relationship between neutron energy and fission fields of 95Zr,140Ba and 147Nd from 235U by measuring the radioactivity of foil with direct gamma spectrometry. The fission yields induced by fast neutrons are get by fast-thermal-ratio method which based on yields from thermal neutrons, yields by thermal neutron are come from absolute measurement. Since fast-thermal-ratio method eliminates uncertainties of gamma intensity, gamma     

Verification of neutron-induced fission product yields evaluated by a tensor decompsition model in transport-burnup simulations

Neutron-induced fission is an important research object in basic science.Moreover,its product yield data are an indispensable nuclear data basis in nuclear engineering and technology.The fission yield tensor decomposition (FYTD) model has been developed and used to evaluate the independent fission product yield.In general,fission yield data are verified by the direct comparison of experimental and evaluated data.However,such direct comparison cannot reflect the impact of the evaluated data on ap...     

The Distribution of Tc in Purex

Tc is an important fission product (fission yield of 99Tc is 6.13%) and has complex chemical behavior. It distributes in many flows of Purex. The influence of Tc can be ignored in military plutonium production reactor because the burning up of it is very low and the production of Tc is little. The burning up of PWR is much deeper and the production of Tc is much higher than the former so the tendency and controlling of Tc in Purex causes popular consideration. The main reason for that is the peculiar chemical property of Tc. Tc co-extracts with Zr, U and Pu in 1A cell and effect the separation of U or Pu in 1B cell by consuming large amount of reductants and     

Experimental study of sheath potential coefficient in the J-TEXT tokamak

Sheath potential coefficient α is a key parameter, which is used to estimate plasma potential(V_p)for edge plasma physics study. Recently, a series of experiments has been carried out under hydrogen plasmas in the J-TEXT tokamak with swept probe, which is employed for current–voltage(I–V) characteristic measurement. Electron temperature is evaluated from I–V curve by three-parameter fitting method, and the electron energy probability function shows that electron distribution is Maxwellian both outside and inside of last closed flux surface(LCFS). Plasma potential is obtained by crossing point between I–V exponential fitting curve and electron saturation current extrapolating line, which is in good agreement with first derivative probe technique. The α coefficient profile in the vicinity of the LCFS is obtained, which is in the range of 2.1–3, and decreases from outside to inside of LCFS.     

Study on Rapid Radiochemical Separation Method for (144)~La

正(144)~La is a short-lived fission product nuclide with a high yield and a half-life of 40.8(4)s.And,it is an important fission monitor in nuclear fission.However,its relative decay data,such as half-life,are uncertain and lack independent yield experimental data,which cannot meet the requirements of the accuracy of nuclear parameters