Optimized analysis of ionospheric amplitude modulated heating parameters for excitation of very/extremely low frequency radiations

It is now well known that amplitude modulated (AM) high frequency (HF) radio wave transmissions into the ionosphere can be used to generate very/extremely low frequency (VLF/ ELF) radio waves using the so-called ‘electrojet antenna’. Duty cycle and heating frequency are analyzed and discussed with the lower-ionosphere modulated heating model, so as to improve the radiation efficiency of VLF/ELF waves in AM ionospheric heating experiments. Based on numerical simulation, the ranges of parametric selectivity in optimal duty cycle and heating frequency ( fHF) are derived. The International Reference Ionosphere 2015 (IRI-2015) model and two-parameter model are used to predict background electron density profiles, and optimized ranges of duty cycle for different density profiles are analyzed and compared. The influences of wave polarizations on optimal duty cycle are also discussed. It is shown that intensity of the VLF/ELF equivalent radiation source (M) firstly rises and then falls with the increase of duty cycle. When using the IRI model, M peaks at a duty cycle of 50%, optimally ranging from 40% −70%. For the two-parameter model case, an optimal duty cycle is 40% and the optimized ranges vary from 30%−60%. Heating with an X-mode polarization is more efficient than with the O-mode case in VLF/ELF wave generation. Nevertheless, an optimal duty cycle is almost independent of HF wave polarizations. To obtain better VLF/ELF generation, optional fHF may be 0.8−0.9 times of foE for the O-mode heating and 0.75−0.85 times for the X-mode polarization case. Finally, the variations of these two parameters in different latitudes are discussed.     

振动流化床微波脱硝研究——减压振动流化床流体力学行为的研究

根据六水硝酸铀酰 (UNH)的脱硝动力学特性 ,将微波加热减压振动流化床用于UNH的脱硝过程 ,是一个很有价值的脱硝工艺。为此 ,首先进行了减压振动流化床流化特性的研究。以床层空隙率为主要评价参数 ,讨论了减压振动流化床的假流化机理和特性 ,着重研究了真空度、床高和振动频率等参数对流化过程的影响。建立了最小流化振动强度的经验关联式。     

低温堆中间回路循环泵隔振设计研究

低温堆作为船用核动力装置使用时,中间回路循环泵选用低转速变频泵。本文针对该泵开展隔振系统设计研究。通过理论分析研究了管道刚度对系统频率的影响,获得了保证泵机组正常运行的隔振系统参数范围。通过有限元数值分析,研究了隔振形式、隔振器参数等因素对泵机组隔振性能的影响。结合正常运行与隔振性能要求提出了低转速变频泵隔振系统的设计方法。结果表明,低温堆中间回路循环泵采用浮筏隔振系统时,通过合理选择隔振器刚度,可使隔振系统的固有频率不在泵机组工作频率范围内,同时具有良好的隔振性能。     

Power Compensation for ICRF Heating in EAST

The source system covering a working frequency range of 24 MHz to 70 MHz with a total maximum output power of 12 MW has already been fabricated for Ion Cyclotron Range of Frequency(ICRF) heating in EAST from 2012. There are two continuous wave(CW) antennas consisting of four launching elements each fed by a separate 1.5 MW transmitter. Due to the strong mutual coupling among the launching elements, the injection power for launching elements should be imbalance to keep the k||(parallel wave number) spectrum of the launcher symmetric for ICRF heating. Cross power induced by the mutual coupling will also induce many significant issues,such as an uncontrollable phase of currents in launching elements, high voltage standing wave ratio(VSWR), and impedance mismatching. It is necessary to develop a power compensation system for antennas to keep the power balance between the feed points. The power balance system consists of two significant parts: a decoupler and phase control. The decoupler helps to achieve ports isolation to make the differential phase controllable and compensate partly cross power. After that, the differential phase of 0 or π will keep the power balance of two feed points completely. The first power compensation system consisting of four decouplers was assembled and tested for the port B antenna at the working frequency of 35 MHz. With the application of the power compensation system, the power balance, phase feedback control, and voltage standing wave ratio(VSWR) had obviously been improved in the 2015 EAST campaign.     

BH1307型康普顿散射谱仪

主要介绍了康普顿散射谱仪的性能、工作原理、结构装置和实验方法。     

Interaction potentials for modeling of ion-surface scattering

Accurate potential data for system Ar⁺, С⁺, Cd⁺, Kr⁺, Ne⁺, Xe⁺, Zn⁺-Xe, Ar⁺-Ar and Ne⁺-Ne were obtained by analyzing the scattering cross-sections. These data extend the existing database of potentials obtained experimentally. To fit better the existing data, a new analytical form of the potential is proposed. The fitting errors analysis shows that the universal potential can be used only for the systems with nuclear charges Z > 18 and in the region where the distances of closest approach are less than R < 8 a_f (here a_f is the Firsov screening length (see below)). The model of individual potentials is suggested, which extends the region of potential application and minimizes the fitting errors.     

Influence of heating effect in Thomson scattering diagnosis of laser-produced plasmas in air

A state diagnosis of laser-produced plasma in air generated by a 1064 nm pulse laser was investigated by the Thomson scattering(TS) method. The evolutions of the electron temperature and electron density were obtained as a function of the time delay which ranged from300–3200 ns. The heating effect produced by the 532 nm probe beam with different energies on the air plasma at different interaction times was further studied using a time-resolved optical emission spectroscopy technique. The influence of the probe beam on the electron density was found to be negligible, whereas its influence on electron temperature is evident. In addition, the heating effect of the probe beam on the plasma strongly depends on the energy of the probe beam, and gradually weakens with increasing time delay. Our results are helpful for further understanding the TS method and its application in plasma diagnostics.     

EAST离子回旋波加热快速阻抗匹配系统的研究

离子回旋波加热是EAST装置最重要的辅助加热方法,在实验中获得了明显的加热效果。射频功率源与天线负载之间阻抗匹配才能保证最大的加热功率输出。在射频加热实验中,等离子体参数的改变将会引起天线负载阻抗的快速变化,为应对这一情况研制出了快速阻抗匹配系统。本文采用解析法和计算机仿真相结合的分析方式,研制了该阻抗匹配系统的铁氧体匹配支节,并对其性能进行了测试。测试结果表明,快速阻抗匹配系统的时间响应速度明显优于传统匹配方式的,可作为实时匹配的候选者。     

5MW核供热堆报警系统的改进

采用欧姆龙可编程控制器改进5MW核供热堆报警系统,克服了原报警系统元器件老化、工作不可靠、功能不够完善的缺陷,提高了报警系统的可靠性和报警功能,改善堆运行的安全性和可靠性。     

Moment-based probability tables for angular anisotropic scattering

This paper presents a strategy for taking into account anisotropy scattering into a Monte Carlo algorithm relying on the subgroup method and developed in the DRAGON lattice code. For the sake of consistency, we limited our Monte Carlo code to the same cross-section libraries available for deterministic methods. However Legendre moments for the transfer cross-sections cannot be directly used during the Monte Carlo random walk, due to the presence of non-positive parts into the distributions. The discrete angle method is proposed to deal with this limitation, following an approach initially introduced in the MORET multigroup Monte Carlo code. We selected a moment approach, originally employed to compute probability tables for resonant cross-sections, to derive consistent sums of Dirac distributions conserving Legendre moments of the angular distributions. A detailed analysis of the applicability of the moment approach is here mandatory. When the moment technique fails due to incoherent Legendre moments, the discrete angle technique is substituted by legacy semi-analytical methods. We illustrate the proposed method using critical benchmarks coming from the ICSBEP handbook by comparison toward S_N and other Monte Carlo results. The impact of the anisotropy scattering is also discussed on a PWR MOX assembly case.     

Optical design for divertor Thomson scattering system for JT-60SA

Optical design for divertor Thomson scattering system in JT-60SA has been conducted. The measurement system will use a Nd:YAG laser at 1064 nm, and scattered photons are collected by a collection optical system. The collection optics consists of primary mirror, secondary mirror, relay optics, and fiber collection optics. The laser transmission mirror and collection optics were designed to be installed in a slender lower port of JT-60SA. The assessment of the measurement errors in temperature was conducted for the designed collection optical system. Because of spatial limitation, the solid angle from the measurement points would be small especially for the measurement points in high field side, and consequently, the temperature errors in the high field side would be considerably large. The effects of several improvements on the error are discussed. Moreover, an assessment for the in-vessel laser transmission metallic mirrors is conducted for the present design.     

低温核供热的系统优化及投资临界值的确定

应用系统工程的理论和方法，将热源，热网，热用户做为一个整体，使其技术和经济指标最佳。为此提出了北有区域热水锅炉房的核共热系统优化数学模型，文中将所述模型归纳为一个有产量约束，多地点，多设备，不同原料，同一产品的工厂选址及其中设备的最优配置问题，在保证供热系统是优的前提下，建立了核供热站投资临界值的判断标准，给出了核供热电站投资临界值及所对应有机燃料价格临界值的定义和求解方法。     

Gaussian approximation for multiple scattering in infinite medium

Lewis theory of the Coulomb multiple scattering is considered in the Gauss approximation for small scattering angles. The model is similar to the Yang theory expressed in terms of the projectile particle true path length. A mixed algorithm of the Coulomb elastic scattering simulation based on condensed along step consideration of small angles and single post step scattering for the rest of angular spectrum is discussed for Monte-Carlo simulation of multiple scattering. The model is in satisfactory agreement with experimental data for electrons and protons.     

5MW THR主换热器设计

文中叙述了5MW THR 主换热器的设计特点,给出了主换热器壳侧的放热系数和总阻力系数。     

Nitrogen Gas Heating and Supply System for SST-1 Tokamak

Steady State Tokamak (SST-1) vacuum vessel baking as well as baking of the first wall components of SST-1 are essential to plasma physics experiments. Under a refurbishment spectrum of SST-1, the nitrogen gas heating and supply system has been fully refurbished. The SST-1 vacuum vessel consists of ultra-high vacuum (UHV) compatible eight modules and eight sectors. Rectangular baking channels are embedded on each of them. Similarly, the SST-1 plasma facing components (PFC) are comprised of modular graphite diverters and movable graphite based limiters. The nitrogen gas heating and supply system would bake the plasma facing components at 350 o C and the SST-1 vacuum vessel at 150 o C over an extended duration so as to remove water vapour and other absorbed gases. An efficient PLC based baking facility has been developed and implemented for monitoring and control purposes. This paper presents functional and operational aspects of a SST-1 nitrogen gas heating and supply system. Some of the experimental results obtained during the baking of SST-1 vacuum modules and sectors are also presented here.     

200MW核供热堆功率调节系统设计原理

简要介绍了２００ＭＷ核供热堆的堆型结构和运动方式，着重介绍了２００ＭＷ核供热堆功率调节系统设计原理和调节控制棒与调节二回路流量协调控制方案，并介绍了调节二回路流理所采用调频电源作为二回路水泵调速的执行机构。     

Predictive Calculation of Neutral Beam Heating Plasmas in EAST Tokamak by NUBEAM Code for Certain Parameter Ranges

A predictive calculation is carried out for neutral beam heating of fusion plasmas in EAST by using NUBEAM code under certain plasma conditions. Results calculated are analyzed for different plasma parameters. Relations between major plasma parameters, such as density and temperature, are obtained and key physical processes in the neutral beam heating, including beam power deposition, trapped fraction, heating efficiency, and power loss, are simulated. Other physical processes, such as current-drive, toroidal rotation and neutron emission, are also discussed.     

Optimization of optical filters for ITER edge Thomson scattering diagnostics

In the ITER edge Thomson scattering measurement system, polychromators with optical band-pass filters and avalanche photodiodes are planned to be used. In this paper, we optimized the transmission wavelength ranges of the optical filters by a numerical method. Since measurements in a high electron temperature range are required for the measurement system, the Thomson spectrum could overlap a strong line emission of D_α when the electron temperature is rather high. It is shown that a filter whose transmission wavelength range is shorter than D_α becomes important to decrease the measurement error in the high temperature range. Moreover, it is found that a filter whose transmission wavelength range is above 1064 nm (laser wavelength) is useful to improve the measurement accuracy, in particular, when the number of filters is more than six.     

Control and acquisition for MAST Thomson scattering diagnostics

The MAST (mega-amp spherical tokamak) Thomson scattering (TS) diagnostics have been radically upgraded and expanded. Eight 30 Hz 1.6 J Nd:YAG lasers have been combined to produce a sampling rate of 240 Hz. The scattered signals are acquired by two spectrometer systems: core and edge. The core system has been built anew: collection optics, polychromators, digitizers, and control computers. It allows measurement of electron temperature and density at 130 spatial points with ∼10 mm resolution across the plasma.The Nd:YAG scattered light signals are registered in 650 channels as polychromator outputs; each channel is registered on two ADCs: at 1 GHz rate in a short interval around each laser pulse and at 100 kHz for background data. The fast ADCs are combined in 26 data acquisition units. Each unit is assembled in a 6 U PXI chassis with embedded controller and six 4-channel 1 GHz ADC cards. Some chassis contain a 96-channel slow ADC card with Ethernet control.The Ruby TS has been rebuilt with a new spectrometer and CCD camera to provide higher spatial resolution - 512 points; the laser has been modified to add double pulse capability.A new control and acquisition system has been developed; it has modular design allowing flexibility and seamless expansion. The system supports event-triggered and real-time operation (will be added in a later stage).A smart trigger device has been developed for TS timing and synchronisation. It provides complex pulse sequences for laser firing with resynchronisation on a number of digital and analogue inputs including plasma events. This device also triggers TS acquisition.The system is integrated by a TS master process running on the dedicated computer; it is represented as a standard MAST data acquisition unit. The Ruby TS is also implemented as a standard MAST unit linked with the Nd:YAG TS by MAST system services.     

低温核供热堆海水淡化装置的建模与仿真

为了研究山东核能海水淡化高技术产业化示范工程的系统最优运行方案和控制策略,建立能正确、全面反映其特性的数学模型是重要的先决条件之一。本文通过对系统的热力性能分析,建立了可用于低温核供热堆的热压缩多效蒸馏与反渗透混合法海水淡化的数学模型,并计算了系统在不同工况下的运行结果。通过与反渗透设备厂商软件计算结果及工程技术方案设计参数比较,结果表明,该模型可正确反映海水淡化系统运行特性,满足进一步研究的需要。