最新刊期
      卷 41 ， 期 2 ， 2018

        LOW ENERGY ACCELERATOR, RAY AND APPLICATIONS

      • Yue YANG,Hexi WU,Yujuan LIU,Yibao LIU,Fansong MENG,Siying ZHANG
        Vol. 41, Issue 2, Article number: 020201(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.020201
        摘要：BackgroundResponse spectrum of radiation sources can be extracted from airborne gamma-ray spectrum by the least square method, however, the analysis accuracy of artificial radioactivity information is affected by the accuracy of response spectrum of radiation sources. PurposeThis study aims to improve accuracy of response spectrum of radiation sources by extracting artificial radioactivity information from airborne gamma-ray spectrum. MethodsWe obtained the linear law between peak intensity of annihilation radiation from cosmic gamma-rays and count rate of cosmic gamma-rays in the last channels by experiments at different detection altitudes and the response spectrum of cosmic gamma-rays by Monte Carlo (MC) simulation. Meanwhile, the response spectrum of radon daughters could be replaced by the response spectrum of stratum radiated from only235U and 238U series, which was verified by experiments at eight detection altitudes. ResultsThe above conclusions were applied to inverse activities of two point sources at different detection altitudes and locate radiation hotspot of artificial radioactivity nuclide. ConclusionThese results show that the proposed approach can extract artificial radioactivity information better. And it provides a valid method to use airborne gamma-ray spectrometry in nuclear emergency.  
        关键词：Airborne gamma-ray spectrometry;Artificial radioactivity;Extract response spectrum   
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        发布时间：2021-05-19
      • Heyong HUO,Yong SUN,Bin TANG,Wei YIN,Bin LIU,Yang WU,Chao CAO,Sheng WANG,Hang LI
        Vol. 41, Issue 2, Article number: 020202(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.020202
        摘要：BackgroundCold neutron is generally yielded by cold neutron source (CNS) in large-size neutron source. The wavelength of cold neutron is similar to that of molecular or atomic structure of lots of materials, which could be adopted to study material macroscopical or macroscopic structure. PurposeThis paper aims to provide input data for neutron transportation in neutron guide and shielding calculation of China Mianyang Research Reactor (CMRR). MethodsCNS was modeled, and ortho-hydrogen and para-hydrogen Monte Carlo database was processed. We calculated the neutron flux in different depths inside the liquid hydrogen moderator, neutron angular distribution and cold neutron gain in the cold neutron (CN) channel's entrance, and got the neutron angular and spatial distributions at the intake of neutron guide. ResultsThe results showed that liquid hydrogen could enhance the cold neutron gain, and neutron beam collimation was promoted by CN horizontal channel. ConclusionThe calculation indicates CNS may significantly improve the performance of neutron beam.  
        关键词：CNS;Physical parameter;Simulated calculation;CMRR   
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        发布时间：2021-05-19

        NUCLEAR ELECTRONICS AND INSTRUMENTATION

      • Junhui YUE,Penghui LYU,Jianshe CAO,Yanfeng SUI,Shujun WEI,Qiang YE,Huizhou MA,Ying ZHAO,Yaoyao DU,Fang LIU
        Vol. 41, Issue 2, Article number: 020403(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.020403
        摘要：BackgroundInjector Ⅰ is a key component of accelerator driven sub-critical system (ADS), phase and energy of the beam need to be known by the operator. PurposeThis study aims to precisely get and control the beam phase and energy of ADS and develop a beam energy measurement system based on fast current transformer (FCT) signal. MethodsFCT detector, signal processing electronics and data acquisition system are designed and integrated to implement the measurement system. The beam energy is measured in terms of beam phase which is obtained by the in-phase and quadrature-phase sampling. The precise phase measurement of the high-frequency signal is realized by the down-conversion technique. ResultsPhase resolutions obtained in the laboratory and on-line operation were ±0.8° and ±2°, respectively. ConclusionThe system proposed in this study meets the design requirements of the linear accelerator.  
        关键词：ADS;High intensity proton linear accelerator;Beam energy;Fast current transformer;In-phase and quadrature-phase sampling   
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        发布时间：2021-05-19
      • Yichao MA,Na ZHU,Sen QIAN,Feng GAO,Jianrun HU,Guoqing ZHANG,Feipeng NING,Hongshe DANG
        Vol. 41, Issue 2, Article number: 020401(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.020401
        摘要：BackgroundLarge area photomultiplier tubes (PMTs) have been increasingly applied to high energy physics experiments, reliable results of PMTs' parameters may not be obtained without earth-magnetic (EM) shielding. PurposeThis study aims to build a test system for EM effect of PMT and obtain its properties in different magnetic field intensity. MethodsBased on the current PMT performance testing system, high-permeability material is used to qualitatively shield the magnetic field; and the EM shielded room entwined with solenoid coil is used to quantitatively shield the magnetic field. Based on the RS-232, universal serial bus (USB) and local area network (LAN) interface communication protocols, test software is developed in LabVIEW. Results & ConclusionThe high voltage supply, light source intensity, magnet strength can be remotely automatically adjusted. And anode signal of PMT is real-time sampled and stored. It is helpful for studying earth-magnetic effect of large-area photomultipliers with this system.  
        关键词：PMT;Magnetic field;Qualitative shielding;Quantitative shielding   
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        发布时间：2021-05-19
      • Geyang JIANG,Songqing TAN,Huan ZHAO,Guanghua CHEN
        Vol. 41, Issue 2, Article number: 020404(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.020404
        摘要：BackgroundShanghai proton therapy facility is the first therapy machine developed in China by Shanghai Institute of Applied Physics, Chinese Academy of Sciences, in which the injector produces different energy proton beams to satisfy requirements of therapy. And the orbit of different beams is constrained by the dynamic power supplies and magnets located on accelerator's main ring. PurposeThis study aims to design a new top-level control system based on traditional static power supply control technology to avoid eddy current's disturbance during magnetic field changing. MethodsPhysics and Industrial Control System) is employed to design the framework. By transferring of pre-defined current data with high speed and intelligent control technology, the problem of eddy current's disturbance is solved affirmatively. Results and ConclusionThis control system has been tested and verified by accelerator main ring's commissioning.  
        关键词：Proton therapy;Dynamic power supply;PCASpy;EPICS   
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        发布时间：2021-05-19
      • Wei CHEN,Jianhua GUO,Shen WANG
        Vol. 41, Issue 2, Article number: 020402(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.020402
        摘要：BackgroundThe large area solar gamma-ray spectrometer (LASGA) is a high-energy radiation detector that consists of anti-coincidence detectors and calorimeter. The calorimeter is composed of 5 orthogonal LaBr3 (lanthanum bromide) layers. Each layer includes fourteen 25 mm×25 mm×400 mm LaBr3 crystals. To achieve large dynamic range, each LaBr3 crystal matches with two independent readout elements with different gains. High gain readout uses a photomultiplier tube (PMT) while the low gain uses photodiode (PD). Since PD has no amplification capability for photoelectrons, the LASGA readout system requires a low-noise readout electronics system to achieve a high signal-to-noise ratio (SNR). PurposeThis study aims to design an electronics prototype system with high dynamic range and low noise properties. MethodsA 64-channel charge sensitive ASIC (VA140) produced by the IDEAS Inc. was used in front-end electronics board. And an Altera cyclone field-programmable gate array (FPGA) (EP3C25Q240C8) was employed to control the ASIC, analog to digital converter (ADC) and digital to analog converter (DAC) chips in data acquisition board. The digitalized detector signal was packaged in field-programmable gate array (FPGA) and sent to personal computer (PC) for processing. ResultsThe performance of the electronics prototype was tested, while the minimum ionizing particles (MIPs) response of LaBr3 with cosmic ray muon was carried out as well. The test results showed that the noise level of the electronics system (@0 pF) and the detection system (connected with PD) at room temperature was about 600 e- and 1800 e- respectively. And there was a good linearity in the range of 0-200 fC. The integral nonlinearity (INL) of 126 channels in the range of 0-180 fC was better than 3%. ConclusionSingle bromide lanthanum unit can measure the energy deposited linearly up to 250MeV. The dynamic range and SNR of the prototype system could fully meet the project's requirements.  
        关键词：LASGA;LaBr3;PD;Readout electronics;Low noise   
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        发布时间：2021-05-19

        NUCLEAR PHYSICS, INTERDISCIPLINARY RESEARCH

      • Jianbing LUO,Peng ZHANG,Te ZHU,Xingzhong CAO,Huaiqiang ZHANG,Shuoxue JIN,Runsheng YU,Baoyi WANG
        Vol. 41, Issue 2, Article number: 020501(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.020501
        摘要：BackgroundHydrogen damage has always been an important research topic in ferrous alloys, and hydrogen induced defects are important factors leading to mechanical deterioration. PurposeThis paper aims to study types of hydrogen induced defects in the hydrogen-charged Fe-1.0%Cu alloy. MethodsPositron annihilation lifetime spectroscopy and coincidence Doppler broadening spectrum were used. ResultsPositron annihilation long lifetime (τ2) of hydrogen-charged specimen annealed at 1073 K for 2 h and 723 K after being cold-rolled was 127.5ps and 124.1 ps, while that quenched before and after being hydrogen-charged was 171.5 ps and 241 ps. And the parameter S increased slightly for hydrogen-charged specimen after being annealed, while that quenched evidently increase due to the presence of vacancy which might interact with hydrogen, leading to the formation of vacancy clusters. The coincidence Doppler broadening (CDB) results show that in the low-momentum region, the ratio curves of the samples after being hydrogen-charged was higher than that before. ConclusionThe results suggest that the types of hydrogen induced defects are related to the state of the samples before being hydrogen-charged. And Cu precipitates have no direct effect on the formation of hydrogen induced defects.  
        关键词：Hydrogen induced defects;Positron annihilation spectroscopy;Vacancy clusters;Dislocations;Fe-1.0% Cu alloy   
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        发布时间：2021-05-19
      • Huawei YU,Yue ZHOU,Xianghong CHEN,Zhigang WANG
        Vol. 41, Issue 2, Article number: 020502(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.020502
        摘要：BackgroundIt has become an inevitable trend to use controlled source instead of isotope neutron source in neutron porosity logging for petroleum exploration, and the availability of measurement results is determined by formation sensitivity, which is required to be of a certain standard. PurposeThis study aims to improve the compatibility and measurement accuracy of the controlled source for neutron porosity logging. MethodsFirst of all, the response equation of formational porosity sensitivity is derviated according to the theoretical formula of neutron porosity logging's response, then the Schlumberger Nuclear Parameter (SNUPAR) program is applied to analysis of its adaptability and factors affecting the sensitivity of neutron porosity logging. ResultsComputaional results show that the deceleration length of neutron is the main role to the change of sensitivity, and the deceleration length is affected by source type and its energy, porosity, lithology, and density. And the neutron energy and rock density are the main factors that affect the sensitivity change. ConclusionThis study provides a theoretical basis for the further study of controlled source neutron porosity logging.  
        关键词：Neutron porosity logging;Controllable source;Formation sensitivity;Deceleration length   
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        发布时间：2021-05-19

        NUCLEAR ENERGY SCIENCE AND ENGINEERING

      • Han ZHANG,Tao ZHOU,Xiaorui TIAN,Lanyu ZHOU,Bangyang XIA
        Vol. 41, Issue 2, Article number: 020601(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.020601
        摘要：BackgroundCorrosive particulate matter in high-temperature and pressure fluid in the primary circuit will be injected into the secondary side with while the steam generator tube rupture accident (SGTR) occurs, which could accelerate corrosion of the secondary side. PurposeA model was built according to actual size of the steam generator heat transfer tube at Daya Bay nuclear power plant with the code of FLUENT adopted to simulate the injection process. MethodsThe standard k-ε model was used in continuous phase to predict the turbulence variation in the rectangular channel, and mixture model was selected as multiphase model to conduct phase transformation, and the discrete particle model (DPM) was used to track the trajectory of the particulate matter. ResultsThe high-temperature speed and concentration field in SGTR appeared near the rupture tube, which would become homogeneous above the tube. There was reflux over the rupture, inducing the particulate matter to flow with the fluid, which would impact the wall of the secondary side, especially that near the rupture tube. Particulate matter aggregation occurs above and back of rupture tube, which might cause deterioration of heat transfer. With the increase of altitude, the influence of the rupture began to diffuse. ConclusionIt is shown that when there is a steam generator tube rupture accident, the particles can cause abrasion on the wall surface and accelerate corrosion with the movement of flow field.  
        关键词：Particulate matter;Steam generator tube;Rupture;Injection   
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        发布时间：2021-05-19
      • Peilun SANG,Hua XIE,Wei SU,Lielin WANG,Wenwen WANG,Zhiqiang FENG
        Vol. 41, Issue 2, Article number: 020603(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.020603
        摘要：BackgroundThe thermal stability of geological cement waste forms containing high pyrolysis products such as Sr and Cs, is an important index for performance evaluation of the nuclear waste solidified body. PurposeThis paper aims to evaluate the thermal stability of geological cement waste forms. MethodsCement waste forms containing Sr, Cs and U were prepared. The changes of mass, volume, compressive strength and other parameters for cement waste forms were observed after heat treatment at different temperatures, and the phase and structure of the samples were analyzed by means of X-ray diffraction (XRD) and scanning electron microscope (SEM). ResultsThe experimental results showed that whenT ≤ 300 degree Celsius, the appearance of the three kinds of cement waste forms had no obvious change; volume shrinkage and the compressive strength loss rate were less than 3% and 25%, respectively. Only part of the hydration product dehydration caused a greater weight loss, corresponding to the decrease of the needle, reticular characteristic organization and the increase of porosity in microstructure. When T > 700 degree Celsius, the cement surfaces had many significant cracks and hydration products had complete phase change, but the structure had not yet collapsed; the microstructure became more dense and had ceramic structural features, which resulted in a compressive strength increasing inversely with temperature, exhibiting good thermal stability at high temperature. The formation of the newly wollastonite phase Ca 3Si3O9 was the main reason for the surface cracking of the geological cement waste forms. ConclusionCompared with ordinary Portland cement (OPC) and alkali activated cement (AAC) cement waste forms, the geological cement waste forms have better thermal stability.  
        关键词：Geological cement waste form;Cs;Sr;U;Thermal stability   
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        发布时间：2021-05-19
      • Nan QIAN,Guanghua WANG,Yu HUANG,Youshi ZENG,Guangliang BAO,Shengwei WU,Wei LIU
        Vol. 41, Issue 2, Article number: 020606(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.020606
        摘要：BackgroundThorCon reactor is a thermal reactor using molten salt (NaF-BeF2-ThF4-UF4) as fuel and coolant and graphite as moderator. Tritium would be produced by nuclear reaction of Be, F in NaF-BeF2-ThF4-UF4 and B graphite, which has strong penetration ability at high temperature, affecting the mechanical properties of the structure and reduce its life. And the tritium is easily changed into trialed water, which may enter the human body, causing internal radiation. PurposeThis paper aims to predict the production of tritium and its main reaction. MethodsThe tritium production reaction was divided into three types based on the number of intermediate products in the reaction channel, such as producing tritium by nuclear reactions with or without intermediate products and by ternary fission. Three corresponding equations were set up accordingly. ResultsThe results showed that the annual tritium production was about 5.444 g, and 88.5% of tritium came from Be. ConclusionIf the amount of Be can be reduced, the yield of tritium will be greatly reduced.  
        关键词：ThorCon reactor;Tritium production;NaF-BeF2-ThF4-UF4   
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        发布时间：2021-05-19
      • Bin ZHANG,Junxiao ZHENG,Xiaojing LI,Boyu BAO,Yixue CHEN
        Vol. 41, Issue 2, Article number: 020605(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.020605
        摘要：BackgroundThe precise calculation of reactor pressure vessel (RPV) fast neutron fluence can be used to evaluate the materials irradiation damage during the designed lifetime and support analyses for a potential plant life extension. The uncertainties of reactor materials and geometry, nuclear data, neutron source and transport solving process can affect the reliability of fast neutron fluence simulation results. PurposeThis paper aims to effectively evaluate the calculation results by thorough analysis of the uncertainties described above. MethodsThis paper analyzed the main origin of uncertainties in the RPV fast neutron fluence calculation and focus on the effect of the neutron source processing method, the Legendre expansion of the anisotropic scattering cross section and spatial discretization method of transport equation. Results and ConclusionModeling of fuel assemblies usually produces a deviation about 20%, the effect of fission nuclide and transport correction methods are about 10%. Through analyses we can understand the weak aspects of the calculation methods and improve the accuracy of calculation results.  
        关键词：Radiation shielding;Fast neutron fluence;Reactor pressure vessel;Discrete ordinates method   
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        发布时间：2021-05-19
      • Bing GUO,Yongbo WEI
        Vol. 41, Issue 2, Article number: 020602(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.020602
        摘要：BackgroundData archiver is an important part of the molten salt reactor control rod drive mechanism (CRDM) prototype control system. It is used to store real-time parameters, alarm and other information of equipment, etc., and accumulate data for further data-based prognostics and diagnostics. PurposeThis study aims to develop a CRDM data archiver based on PostgreSQL. MethodsA dual-machine hot standby technique was employed to improve the performance of database and store data reliably. The control rod position retrieval tool was implemented by using Java programming. ResultsA data archiver based on PostgreSQL was developed and applied to CRDM prototype. ConclusionThe data archiver designed based on PostgreSQL is proved to be an advanced, low cost and stable system.  
        关键词：PostgreSQL;Data Archiver;EPICS;Control rod drive mechanism   
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        发布时间：2021-05-19
      • Jun YAO,Xisi ZHANG,Wenjun HU,Xiang CHAI,Yanhua YANG
        Vol. 41, Issue 2, Article number: 020604(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.020604
        摘要：BackgroundLead-cooled fast reactor (LFR) is one of six candidates for Generation Ⅳ nuclear systems. Although lead-bismuth eutectic (LBE) has excellent neutron properties, thermal-hydraulic performance and inherent safety features, the structure and cladding materials could be eroded by LBE coolant. The erosion products could accumulate in fuel assembly and grow as a blockage influencing the heat transfer of cladding and coolant. PurposeThis study aims to investigate the block parameter effect on thermal-hydraulic performance of single fuel assembly in lead-bismuth subcritical reactor under various blockage accidents. MethodsBased on actual geometry and material properties, modeling of single fuel assembly was established. Five blockage accidents were numerically simulated by the commercial computational fluid dynamics (CFD) software STAR-CCM+ with different block parameters. ResultsTemperature variations along the axial direction of cladding inner face and subchannel center were obtained and compared. Axial velocity distributions around block were analyzed. Influence of block parameters for the coolant backflow and the property of flow fields were achieved. ConclusionThe maximum temperature rise unanimously occurs inside block. Different block parameters diversely influence flow and heat transfer.  
        关键词：LFR;Blockage accident;Block parameter;CFD   
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        发布时间：2021-05-19

        NUCLEAR CHEMISTRY, RADIOCHEMISTRY, RADIOPHARMACEUTICALS AND NUCLEAR MEDICINE

      • Feng WANG,Jianhua YANG,Qing XIE,Shizhen ZHAI,Zhi YANG
        Vol. 41, Issue 2, Article number: 020301(2018) DOI: 10.11889/j.0253-3219.2018.hjs.41.020301
        摘要：BackgroundPositron emission tomography/computed tomography (PET/CT) is a routine diagnostic method of particular importance for treatment evaluation and management in oncology. It is very important for PET/CT diagnosis to produce good quality and quantity positron nuclides using medical cyclotron. PurposeThe effect of irradiation conditions and bombardment parameters on positron nuclide 18F production was analyzed to acquire the optimized production conditions and optimum bombardment parameters. MethodsOrigin 9.0 software was used to analyze the change of 18F yield with different proton beam current and bombardment time. Monte Carlo method was applied to establish the target chamber model of proton irradiation, and the proton energy, thicknesses of Havar foils and the 18O water were analyzed to obtain the optimum conditions of beam current, bombardment time and the proton energy,etc. ResultsProton beam should thoroughly irradiate on target chamber center to make the best of beam current for triggering as much as nuclear reaction. When 20-MeV proton beam was used to produce 18F, the thicknesses of Havar foil and the target water were recommended to be 60 μm and 3 mm, respectively. Usually, the yield of 18F increases with the beam current. The longer the bombardment time was, the higher the yield of 18F. But with bombardment time increased, the trend of yield became slower. The bombardment time was suggested approximately 60 min. ConclusionIt is necessary to select the appropriate thicknesses of Havar foil and the 18O water for positron radionuclide 18F production (this paper shows that the thicknesses of Havar foil and the 18O water should be 60 μm and 3 mm when the proton energy is 20 MeV). The irradiation time was suggested approximate 60min to obtain high yield of 18F. Furthermore, irradiation should be started after the cyclotron run for a period of time for stabilization.  
        关键词：Cyclotron;Proton;18F;Production conditions;Monte Carlo method   
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