α,β计数管

我们所制的α,β计数管是钟罩计数管,计数管的一端设有极薄的云母窗,β计数管的云母窗厚度为3—5毫克/厘米~2,α计数管的厚度在3毫克/厘米~2以下,α,β计数管云母窗如用玻璃凹泡代替就成为凹泡计数管。     

Prospects for using microelements in VVÉR reactors

The paper deals with prospects for using micropins in VVéR reactors in order to provide a radical improvement in station safety. The most efficient arrangement is direct micropin cooling by the water moderator in assemblies involving transverse flow around a micropin layer. That design provides neutron-physics and thermohydraulic characteristics similar to those of VVéR reactors containing rod elements. The micropins do not require any change in the reactor design, and pin assemblies containing them may be built to be identical with those in traditional VVéR reactors as regards dimensions, connecting units, and thermohydraulic and neutron-physics characteristics. The conditions occurring in major accidents show that such reactors containing micropins can provide radiation safety in any major accident, and it is particularly promising to use them to extend the working lives of first-generation power stations not fitted with pressurized vessels or sealed shells. Translated from Atomnaya énergiya, Vol. 86, No. 6, pp. 443–449, June, 1999.     

Cold-state physical characteristics of ÉGP-6 reactors after upgrading

Measurements and calculations important to safety are reported for éGP-6 reactors in the cold state. These data give the sufficient number of manual control rods to be fitted with upgraded RS-AZ drives, and it is shown that the reactor subcriticality can be determined. Measurements have been made on the temperature coefficients of reactivity, the reactivity change when the coolant is lost from the new cooling channels for the control rods, and the reactivity increment caused by using these new channels. Bilibinsk Nuclear Power Station. Translated from Atomnaya énergiya, Vol. 86, No. 2, pp. 94–99, February, 1999.     

低水平γ,β放射性测量仪

在低水平α、β放射性测量中,可以采用不同的探测器,如半导体探测器,闪烁计数器及流气式正比计数管等。 半导体探测器对带电粒子的测量,有较高的探测效率和较低的本底。由于我国目前生产的探测器有效面积较小,使仪器探测灵敏度受到限制,加之它的表面机械性能较差,污染后去污不方便,且容易损坏。 ZnS(Ag)闪烁计数器具有良好的鉴别α粒子和β、γ辐射的能力,本底较低,可用于α粒子的测量,但探测效率不高。     

用α,β谱仪测量人工α,β放射性气溶胶体积活度的试验 …

本文介绍了用αβ谱仪系统同时测量αβ谱，实现Ｒｎ／Ｔｈ子体补偿，确定超铀α核素气溶胶体积活度及人工放射性气溶胶总β体积活度的技术途径，利用ＲｓＡ，ＲａＣ′α峰的二段时间计数可确定空气中ＲａＡ，ＲａＢ，ＲａＣ的气溶胶体积活度，相应的，也能给出了ＲａＢ，ＲａＣ对总β计数的贡献，根据一般环境条件下的平衡比，用ＴｈＣ′的α计数修正Ｔｈ子体对αβ测量的影响，＾２３９Ｐｕ或／＾２４１Ａｍ人工核素的α计数，可通     

Cathodic polarization curves of the oxygen reduction reaction on various structural materials of boiling water reactors in high temperature–high purity water

Cathodic polarization curves of the O₂ reduction reaction were measured by using electrodes made from typical structural materials of boiling water reactors (BWRs) to evaluate the effects of kind of material on the electrochemical corrosion potential (ECP) calculation. To estimate ECPs at any region in the BWRs on the basis of the BWR environmental conditions, anodic and cathodic polarization curves should be obtained in advance under relevant conditions. The concentration of oxidants such as O₂ and H₂O₂ in coolant changes depending on the region in which they exist. As well, reduction reaction rates might differ depending on the kind of materials. In this work, the cathodic polarization curves of type 316L stainless steel (316L SS) and Alloy 182 were measured in high purity water at 553 K with different O₂ concentrations and compared with those of type 304 SS (304 SS). The results showed that the cathodic polarization curves differed depending on the kind of materials at the activation-controlled region. But, the difference in the ECP vs. O₂ concentration relationship was small when the ECPs were calculated by using both anodic and cathodic polarization curves measured on the objective material.     

Kinetic studies of the α-β phase transition in the Zr1%Nb cladding for nuclear reactors

The α-β phase transition of a zirconium alloy doped with 1 mol% of niobium (E110 alloy) is investigated using differential scanning calorimetry. The onset and endpoints of the transition are identified from the measured heat flow signal and from the integration of the observed peak the extent of the α-β phase change is calculated as a function of temperature. The experiment has been performed at different heating rates and a shift of the onset temperature with increasing heating rate was observed. From the dataset the equilibrium transition curve has been extrapolated and compared with other types of zirconium-based cladding materials.     

Radionuclide inventories in the discharged fuels of PHWR-220, BWR-160, VVER-1000 and the conceptual ATBR-600 reactors – A case study

Radionuclides content in the discharged fuel of the conceptual thorium breeder reactor ATBR-600 has been assessed and compared against other thermal power reactors considered in Indian nuclear power programme. The contribution of actinides and the fission products inventories in the discharged fuels are separately estimated and assessed. The ATBR-600 reactor is suggested for closed fuel cycle option. The relatively large presence of the unspent plutonium would in fact be recycled. Nonetheless, the data has been presented in the event of operating ATBR-600 like other present day power reactors in a once through fuel cycle mode.     

在β,γ混合輻射中用輻射仪分别測量β,γ射线的方法

在探矿、示踪原子的应用与輻射防护工作中,常有在β,γ混合輻射中分別测量丫射线剂量(或通量)与β粒子通量的必要。通常使用計数管作探測元件的β,γ輻射仪均有类似于图1的結构。指示仪表的讀数取决于計数管单位时間內所計的粒子数。不同的仪器有不同的     

Development of a thermal–hydraulic analysis code for research reactors with plate fuels

The thermal–hydraulic analysis code THAC-PRR has been developed with Visual Fortran 6.5 for the investigation of plate type fuel reactors. It is based on the fundamental conservation of mass, momentum and energy, and proper constitutive correlations for flow friction factor, heat transfer and thermophysical properties. Moreover, a simple and improved lumped-differential method has been adopted to analyze the conjugate heat transfer between the fuel plate and the coolant. The Reactivity Insertion Accident (RIA) and Loss Of Flow Accident (LOFA), which have been defined in the IAEA 10 MW MTR Benchmark program, were analyzed with this developed program for the code-to-code validation. Good agreement was achieved. Furthermore, the accidents due to the partial (95%) and total (100%) blockage of one channel in the IAEA 10 MW MTR were investigated with THAC-PRR. The results showed that if the blockage occurred in the average channel, there was no boiling occurred even the channel was totally obstructed. The reason was that the heat was transferred to the adjacent channels by conduction through the fuel plates which formed the obstructed channel. However, if the blockage occurred in the hot channel, boiling did occur. This indicated that it is very important to consider the interaction between the blocked channel and the adjacent channels in this type of transient.     

Measurement and analysis of noise spectra – an effective diagnostics method for nuclear reactors

The basic principles of measuring and analyzing nuclear-reactor noise are described. The results obtained for the IBR-2 reactor by the noise method are presented. It is shown that analysis of the noise spectra of the power and the main reactor parameters makes it possible to find deviations from normal reactor operation at the level 10^–6 ∆k/ k of the change in reactivity.     

Industrial processing of the spent fuel of npp operating with water-moderated VVÉR-440 reactors

Mayak Production Complex. Sverdlovsk Scientific-Research Institute of Chemical Machinery. Research-cum-production Complex VNIPIET. Ministry of Atomic Energy, Russian Federation. A. A. Bochvar All-Union Scientific-Research Institute of Inorganic Materials. Translated from Atomnaya Énergiya, Vol. 72, No. 5, pp. 432–436, May, 1992.     

BH1216型低本底α,β测量装置

一、概述 BH1216型低本底α,β测量装置是FH1914型低本低β测量装置的改进型,由于对主探测器、反符合探测器和电子学线路进行了改进,对于同一种样品进行一次测量可同时给出样品中的总α,总β活度,克服了FH1914型低本底β测量装置中α,β交叉的缺点。装置对~(90)Sr-~(90)Yβ源的2π效率≥40%时,本底最好可达0.04计数/cm~2·min;效率≥60%时,本底最好可达0.06计数/cm~2·min;效率≥70%时,本底最好可达0.08计数/cm~2·min。对于500mg的KCl的2π效率≥60%时,本底最好为0.06计数/cm~2·min。对于~(239)Pu α源的2π效     

XWYI型可携式α,β表面污染仪

放射性表面污染的测量,无论是对确定工作区的环境清洁度,还是对检验那些预防和控制污染的方法的有效性来说,都是十分重要的。由于射线的类型和能量以及污染表面的性质和几何形状的不同,往往希望测量表面污染的仪器能满足多功能,小型轻便和操作简易等要求。为此,我们参照英国的PCM5型α,β污染仪试制了XWY1型可携式α,β表面污     

β-NMR Study on ^29P （I^π=1/2＋, T1/2=4.14s）

A. Navin and some others have confirmed that there exists halo structure in ^26,27,28p isotopes. Chen Fence and some others got the same result with different theoretical models. At the same time, they plotted the total density distribution of protons and neutrons of ^25-31p changes with the radius. The figures showed that the proton density distribution of ^25-31p has long tail and the tail decreases as the mass number increases. The proton density distribution of ^29p obviously has long tail.     

γ-Ray spectra excited in inelastic scattering of fast neutrons on manganese,aluminum, iron,copper, tin,and antimony

The study of inelastic scattering of fast neutrons is an important problem of both theoretical and practical interest. From the theoretical point of view the importance of this work lies in the possibility of obtaining data concerning levels in stable nuclei. The practical value arises in connection with the important role played by inelastic scattering of neutrons in fast-neutron reactors as well as the fact that the extension of reactor theory to fast-neutron reactors requires data on the spectra of inelastically scattered neutrons [1, 2]. In this connection the necessity for developing a neutron spectrometer for fast neutrons and-spectroscopy for inelastic neutron scattering is obvious. In the last 5–7 years a great deal of work has been devoted to this problem.The present work reports on measurements of-ray spectra excited in inelastic scattering of 2.8 Mev neutrons by manganese, aluminum, iron, copper, tin and antimony. The measurements were carried out with a scintillation spectrometer consisting of an NaI(Tl) crystal, a FEU-1B photomultiplier and a 50-channel pulse-height analyzer with a magnetic-drum memory. The spectrometer resolution was 6.5–7% for-rays from Co⁶⁰.-Rays of the following energies (Mev) were found: in manganese 0.97, 1.41, 1.92, 2.3; in aluminum 0.84, 1.00, 1.80, 2.16; in iron 0.84, 1.25, 1.46, 1.70; in copper 0.63, 0.78. 0.96, 1.12, 1.38, 1.46, 1.72, 2.03; in tin 0.84, 1.16, 1.50, 1.80, 2.16; in antimony 1.04, 1.50, 1.84, 2.16.Abbreviated version of a paper appearing in the Ukrainian Journal of Physics.The authors wish to take this opportunity to thank L. M. Beliaev and G. F. Dorbrzkanskii of the Institute of Crystallography, Academy of Sciences, USSR for making the NaI(TI) crystal and for kndly allowing us to use it in carrying out the present work.