最新刊期
卷 41 ， 期 4 ， 2018
- 摘要：BackgroundThe solid polymer tritium electrolysis enrichment method is the mainstream to concentrate low-level tritium water. Its performance depends on whether it can obtain high tritium recovery. As the volume concentration factor is constant, the tritium separation coefficient determines the value of tritium recovery. PurposeThis paper aims to enhance the tritium recovery of solid polymer electrolysis tritium enrichment system and improve the performance of tritium enrichment system. MethodsThe separation coefficient was adopted as an index to optimize the solid polymer tritium enrichment system on cathode and anode materials, electrolytic current and electrolysis temperature. ResultsWith the initial volume ≥ 400 mL, the current of electrolytic water electrolysis device at 15 A, the temperature at 5℃, electrolysis residual volume ≤ 25 mL, we have been obtained the optimized tritium separation coefficient of 6.5, the tritium concentration system recovery factor ≥ 65%. ConclusionThe performance of solid polymer electrolysis tritium enrichment system almost achieves international level.关键词：Solid polymer electrolysis tritium enrichment;Tritium recovery factor;Separation coefficient;Electrocatalysts;Membrane electrode assembly
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发布时间：2021-05-19 - 摘要：BackgroundThe GEANT4 application for tomographic emission (GATE) Monte Carlo simulation platform based on GEANT4 toolkit has come into widespread use for simulating positron emission computed tomography (PET), single photon emission computed tomography (SPET) imaging systems and is potentially useful for a board range of simulations, including those where the absorbed dose is the principal observable. PurposeThis paper aims to analyze the application in calculating the dose conversion coefficient of human voxel phantom, and provides a new solution for calculating the dose of voxel phantom in photon radiation field. MethodsThe voxel data of human voxel phantom KTMAN-2 was reversed to CT by self-compiled MATLAB program, and CT was converted into GATE voxel model file by VV software. To obtain photon dose conversion coefficients, GATE and MCNPX were used to simulate the photon transport for 23 monoenergetic photon beams from 0.01 MeV to 10 MeV under six standard irradiation geometries in human voxel phantom, and the results of GATE and MCNPX were compared and they were also compared with the recommended values in the ICRP 74 and ICRP 116 publication. ResultsGood agreement was found for both GATE and MCNPX, the difference of organs within 3% except small organs (pituitary, tonsils, thyroid, etc.); the calculated values were reasonable in comparison with the values from ICRP 74 and ICRP 116, but under some irradiation conditions, differences are observed in calculated values of KTMAN-2 compared with ICRP 74 and ICRP 116. ConclusionGATE provides a new method for dose calculation based on voxel model. The dose conversion coefficient calculated in this paper would be of great significance for analyzing the difference in photon dose conversion coefficients between Asian male and ICRP male reference phantom.关键词：Human voxel phantom;Dose conversion coefficient;GATE;KTMAN-2
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发布时间：2021-05-19
NUCLEAR PHYSICS, INTERDISCIPLINARY RESEARCH
- 摘要：BackgroundThe fissile nuclides in the molten salt reactor (MSR) will produce a large number of fission products under normal operation conditions, which would fill the entire primary loop system. The decay of the fission products would generate heat all the time, even though the fission power stopped. The accurate analysis of the decay heat has great significance on the safety analysis of the primary loop pipe and equipment. PurposeThis study aims to establish a numerical model for analyzing the decay heat of the primary loop. MethodsThe numerical flow model of the decay heat was established for 2 MW MSR (Thorium Molten Salt Reactor-Liquid Fuel 1, TMSR-LF1) designed by Shanghai Institute of Applied Physics (SINAP), Chinese Academy of Sciences, and then solved by using Mathematica 7.0. The simulation results of the static burning of TMSR-LF1 of SINAP and molten salt reactor experiment (MSRE) of Oak Ridge National Laboratory, were compared with that of ORIGENS program, the deviations are within the range of ±4% and ±2.76% respectively. The decay heat distribution in primary pipe and equipments of the primary loop system under normal operating conditions of TMSR-LF1 was quantitatively analyzed to find the distribution rule of decay heat under different flow rates. ResultsThe deviations of decay heat for TMSR-LF1 and MSRE, calculated by Mathematica and ORIGENS, are within the range of ±4% and ±2.76% respectively, under normal operating conditions. The decay heat accumulated rapidly in each region about 20 s after start-up of the reactor in full power and flow rate, and then began to rise slowly and tend to be an equilibrium value. After equilibrium, decay heat of core active area account for 46.7% of the total decay heat, and the upper plenum, the hot leg#1, the main pump, the hot leg#2, the heat exchanger, the cold leg and the lower plenum area accounted for 31.8%, 1.21%, 14.6%, 0.89%, 2.21%, 1.67% and 0.94% respectively. ConclusionThe established analytical method and conclusions can provide important reference for thermal hydraulic safety analysis, residual removal system design, reactor power regulation and safety control.关键词：Molten salt reactor;Primary loop system;Decay heat;Flow model
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发布时间：2021-05-19 - 摘要：BackgroundMolten corium-concrete interaction (MCCI) would cause the containment to lose its protection function and result in considerable radioactive fission products release into atmosphere. PurposeThis study aims to assess the potential failure risk of containment during MCCI process by investigating and analysis the effect of concrete type on the MCCI phenomenon. MethodsThe integrated containment and cavity models for large power passive reactor were built with MELCOR 2.1 code, a fully integrated, engineering-level computer code for severe accidents. The interactions of molten corium with typical basaltic concrete and limestone-sand concrete were investigated, respectively. The potential failure risk of containment due to the MCCI phenomenon was evaluated. ResultsThe analysis results show that the ablation rates of those two typical kinds of concrete are apparent different during MCCI process, and the basaltic concrete has higher ablation rate on the side of the cavity than the limestone-sand concrete whilst the letter has more non-condensible gas production. ConclusionThe failure time of containment basement far exceeds 24 h after MCCI starts, independent of the concrete type. All the calculation values of the containment pressure are below the pressure load level "C", which satisfies the goal in protection the fission products boundary for 24 h.关键词：MELCOR 2.1;Containment;MCCI;Non-condensible gas;Severe accident
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发布时间：2021-05-19 - 摘要：BackgroundThe property of temperature-and corrosion-resistance of high temperature optical fiber depends on the coating layer on the surface. PurposeThis study aims to find an optical fiber withstanding high temperature fluoride salt corrosion. MethodsGold-plated optical fiber was selected for experimental test in the fluoride salt of the molten state at temperatures of 600℃ and 650℃. The samples were taken out after 24 h steeped in the high temperature molten salt, and then observed under the scanning electron microscope (SEM). ResultsThe SEM images of gold plating layer of the optical fiber show that the surface of the fiber remained intact, and there is no obvious sign of corrosion. ConclusionIt can be applied to the molten salt reactor for the short-time temperature measurement.关键词：High temperature fiber;Optical fiber temperature measurement;Molten salt
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发布时间：2021-05-19 - 摘要：BackgroundIn reactor core, recoil protons produced by fission neutrons may interact with coolant of the primary circuit and produce radioactive nuclides through reactions 16O(p, α)13N, 18O(p, n)18F and 11B(p, n)11C. Positrons emitted by the radioactive nuclides, 13N, 18F and 11C, etc., can be detected by coincidence measurement, hence the leakage of the reactor coolant inferred. However, calculation of the source terms of the nuclear reactor core are mainly based on solving the point burn-up equation or simulation of the reactivity based on Monte Carlo method, lacking the capability to simulate (p, α) and (p, n) reactions for protons at 0~20 MeV. PurposeThis study aims to simulate the production of source terms generated by protons for the reactors of Qinshan's second nuclear plant. MethodsFull reactor core of the reactor was modeled in GEANT4. Source sampling description based on general particle source (GPS) was achieved in consideration of radial and axial power distributions of the reactor core. G4-NONU was developed using C++ for neutron transportation to realize the function of NONU card in MCNP (Monte Carlo N Particle Transport Code) by modifying the fission model in GEANT4. Energy spectrum of recoil protons in water of the primary circuit was calculated, so were the reactivities of 16O(p, α)13N, 18O(p, n) 18F and 11B(p, n)11C. Eventually, concentrations and activities of 13N, 18F and 11C of the primary circuit were computed. Results and ConclusionMethods for description of source terms for pressurized water reactor in GEANT4 were established and nuclear reactor problems involving charged particles can be simulated by self developed G4-NONU, which is an enrichment of the simulations tool for nuclear reactor.关键词：GEANT4 simulation;Pressurized water reactor;Charged particles;Source terms of the primary circuit
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发布时间：2021-05-19 - 摘要：BackgroundTo narrow the gap between international thermonuclear experimental reactor (ITER) and a demonstration reactor (DEMO), a Tokamak device, Chinese fusion engineering test reactor (CFETR) was proposed and is being designed. While the design and discussion of blanket for CFETR is still ongoing. PurposeThis study aims to present a new conceptual design of a helium cooled solid breeder blanket and to get the results of thermal-hydraulic analysis of the blanket for normal operating conditions. MethodsThe flow characteristic was obtained by theoretical calculation of engineering fluid mechanics and the thermal analysis result was given by fluid-solid coupled finite element analysis using the computational fluid dynamics (CFD) software CFX. ResultsMass flow rate, mean velocity and pressure drops of coolant in various channels of the blanket were given by the theoretical calculation. Temperature field of the whole blanket module and peak temperature of different functional materials were given by the FEA. ConclusionThe parameters of coolant are in acceptable range. Rules about temperature limits of different functional materials are followed in normal operating conditions.关键词：CFETR;Solid breeder blanket;Structural design;Thermal-hydraulic
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发布时间：2021-05-19
NUCLEAR ENERGY SCIENCE AND ENGINEERING
- 摘要：Low pressure distillation technology can be used to separate components of spent fuel due to their different volatility. This paper introduced the development of molten salt distillation technology briefly. First, the fluoride salts from molten salt experiment reactor (MSRE) were recovered and reused in Oak Ridge National Laboratory (ORNL) of USA. In the last decades, the distillation technology was used to purify the cathode products after the electrochemical treatment of spent fuel from pressure water reactor (PWR) or fast reactor in USA, Japan, Korea, France and so on. Then the challenges of distillation technology in both the salt recovery and cathode products purity were illustrated and development strategies were suggested. It is further pointed out that distillation separation combined with chemistry reaction may cope with the grave challenges of spent fuel pyroprocessing for thorium molten salt reactor (TMSR).关键词：Spent fuel;Pyroprocessing;Molten salt;Low pressure distillation
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发布时间：2021-05-19
REVIEW ARTICLE
- 摘要：BackgroundThe reaction of D-D may generate radiation in the experiment of experimental advanced superconducting Tokamak (EAST), and the total power can reach several tens of megawatts. PurposeThis paper aims to assess the ionizing radiation effects of surrounding environment and staff. MethodsApplying the optically stimulated luminescence and solid nuclear track, we did the cumulative monitoring of neutron and gamma radiation dose in experimental sites surrounding Tokamak device hall, i.e., personnel entrance access, inside and outside of the screen door, peripheral diagnosis room and the main control room. Thirteen monitoring points were arranged for continuous measurement throughout years, taking a period of 90 d for dose tablets replacement and reading. ResultsFrom 2010 to 2017, there were 165 staffs on key positions in EAST, and a radiation dose database of the experimental sites and staff was established using the Access software. The effective dose of monitoring points outside the installation hall and the workers were less than 0.5 mSv after deducting natural background radiation. ConclusionThis paper provides a preliminary reference for the management system and specification of radiation protection for Tokamak fusion devices.关键词：Tokamak;Neutron and gamma cumulative dose;The dose of experimental sites and staff
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发布时间：2021-05-19 - 摘要：BackgroundSpot scanning is adopted as the operating mode for the beam delivery system of the Shanghai Proton Therapy Facility. PurposeTo meet the needs of dose rate and dose accuracy, a precise spot scanning position control system was developed. MethodsQuadratic polynomial and smoothed thin-plate splines fitting has been adopted in mapping the relationship between the target scanning magnet strength and spot position at ISO center, and the relationship between the target scanning magnet strength and the spot position at ion chamber. During the treatment process, the target magnetic field is calculated according to the target spot position at ISO center given by the treatment planning system. A feed forward magnet strength control strategy is used in controlling the scanning magnetic to reach the target magnetic field. The position of the following spot is corrected through comparing the target spot position and the spot position readout from the ion chamber. ResultsBeam test showed that the maximum position error in X and Y direction was 0.8 mm and 0.6 mm respectively, and both of the root-mean-square were 0.2 mm. ConclusionAccurate spot scanning has been achieved by the spot scanning position control system.关键词：Proton therapy;Spot scanning;Scanning position control;System design
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发布时间：2021-05-19
LOW ENERGY ACCELERATOR, RAY AND APPLICATIONS
- 摘要：BackgroundThe gamma ray monitor (GRM) is one of the four payloads of the space variable objects monitor (SVOM) scheduled to be launched in 2021. PurposeThis study aims to design data management module of GRM for data interaction with SVOM. MethodsThe SpaceWire bus architecture based on the AT7910 chip is adopted to complete data transmission at the data transfer rate of 100 Mbit·s-1. Channel identification is achieved by the construction of group adaptive routing (GAR) to determine the status of the hot and cold spare device, and select the data transmission channel to complete the information transmission between GRM and SVOM. Results & ConclusionThe test results show that GRM data management module can utilize the SpaceWire bus to realize the data exchange with the satellite platform.关键词：Gamma ray monitor;Data management;SpaceWire bus
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发布时间：2021-05-19 - 摘要：BackgroundPositron emission tomography (PET) is a highly sensitive and quantitative molecular imaging modality. PET detector usually consists of a high efficient scintillator array and a position sensitive photodetector or a photodetector array. The spatial resolution of a PET detector is mainly determined by the crystal size of the scintillator array and the quality of the flood histogram of the detector. PurposeThis paper aims to study the effects of the thickness of the light guide used between the scintillator array and photodetector in the flood histogram and energy spectra of the detector by the lutetium-yttrium oxyorthosilicate (LYSO) scintillator array and silicon photomultiplier (SiPM) array most commonly used in current small animal PET scanners. MethodsThe scintillator array is 12×12 with a crystal size of 0.89 mm×0.89 mm×10 mm. A Hamamatsu 4×4 SiPM array with a 3mm×3 mm pixel size and 0.2 mm gap between pixels is used. The light guide is made of plexiglass with thickness of 0.5 mm, 1.0 mm, 1.5 mm, 2.0 mm and 2.5 mm. ResultsThe results show that the uniformity of the flood histogram and the capability of resolving the edge crystals improves as the thickness of the light guide increases. The spot size of each individual crystal in the flood histogram increases and the dynamic range of the flood histogram decreases as the thickness of the light guide increases. The light guide has almost no effect on the average photopeak amplitude and energy resolution of the crystal energy spectra. Overall light guide of 1.5 mm provides the best detector performance. ConclusionThe results of this work provide guidance for developing small animal PET detector using LYSO array with a crystal cross section of about 1 mm×1 mm and SiPM array with a pixel size of 3 mm×3 mm.关键词：PET detector;Spatial resolution;Light guide;Flood histogram;Energy spectrum
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发布时间：2021-05-19 - 摘要：BackgroundTime-of-flight measurement is a basic method to identify charged particles in high-energy physics experiments. PurposeThis paper aims to realize time measurement resolution of flight time detectors in high-energy physics experiments within 50ps. MethodsBased on the 0.13μm complementary metal oxide semiconductor (CMOS) process, we designed a single-cycle time to digital convertor (TDC) as a fine counting module in time interpolation and built a closed-loop test system. ResultsThrough analysis of measured data, we designed the comparison test under the same conditions, and found the source of TDC scale heterogeneity, and proposed the corresponding calibration method. ConclusionThe resolution of TDC after calibration is up to 57ps and the accuracy is better than 40 ps.关键词：Application-specific integrated circuit;TDC;Closed-loop test system;Comparison test
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发布时间：2021-05-19
NUCLEAR ELECTRONICS AND INSTRUMENTATION
- 摘要：BackgroundThere is no commercial soft X-ray cryogenic radiometer available for 4B7B experiment station on Beijing synchrotron radiation facility (BSRF). PurposeThis study aims to design and implement a soft X-ray cryogenic radiometer to measure the X-ray power from 30nW to 1 μW for BSRF. MethodIntensive experiments were performed to find the key points to reduce the uncertainties of X-ray power measurement. The temperature stabilities of the heat sink, the absorber and the control of thermal radiation background fluctuation are principal factors influencing the accuracy whilst the temperature stability of the heat sink is the precondition of the absorber temperature stability. The heating power on the absorber is determined by the X-ray power and adjusted by the temperature control system. And for low X-ray power measurement, the uncertainties can be affected by the fluctuation of thermal radiation background. Result & ConclusionThrough optimizing the temperature control system of the heat sink and the absorber, and improving the design technics of the heat link, the standard deviation of the heat sink can be kept under 10 μK, and the absorber is kept under 15 μK. The fluctuation of thermal radiation background can be stabilized less than 0.06 nW by improving the thermal environment and design special light pipes. The result of 30 nW X-ray power measurement shows that total uncertainties are less than 1% (k=1).关键词：Cryogenic radiometer;Temperature control;Thermal radiation background;Uncertainties
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发布时间：2021-05-19
SYNCHROTRON RADIATION TECHNOLOGY AND APPLICATIONS
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