检索结果-南通市图书馆

Prototype of an Echo-PIV Method for Use in Underwater Nuclear decommissioning Inspections

Journal of Flow Control, Measurement & Visualization 2019年第1期7卷 28-43页

作者： Takuya Kawachi Robert Malkin Hideharu Takahashi Hiroshige Kikura Tokyo Institute of Technology Tokyo Japan University of Bristol Bristol United Kingdom

The ongoing decommissioning of the Fukushima Daiichi (1F) nuclear power plant requires the inspection of the inside of containment vessels that have been submerged in water. These inspections must locate leaks and map the distribution of fuel debris in water with very low visibility. This paper reports the design and testing of an echo-PIV system that uses a single divergent signal wave and delay-and-sum processing to efficiently map the interior and fluid flow within a submerged vessel. The diverging wave and delay-and-sum processing improve upon the performance of conventional ultrasound PIV methods specifically to meet the demands of containment vessel inspections. The imaging method uses an ultrasonic linear sensor array that emits a diverging wave that covers a wide angle with a single transmission. The delay-and-sum algorithm combines echo signals recorded by each element of the sensor array. We optimized the design of an echo-PIV system in laboratory-scale tests, and then tested the prototype with a mockup of a containment vessel in a water tank. The small-scale prototype successfully located a mock leak and mapped the surface of a piece of mock debris. This prototype can be scaled up readily for inspections at the Fukushima Daiichi plant.

关键词： Echo-PIV Diverging Beam Transmission Delay-and-Sum Algorithm Vector Flow Mapping Surface Mapping 1F decommissioning

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Simulation Study on Final Status Survey of decommissioning Site

Simulation Study on Final Status Survey of Decommissioning S...

引用

The Second Asian and Oceanic Congress for Radiation Protection

作者： Gu Jiande Zhang Taiming(Institute of Nuclear Physics and Chemistry CAEP Sichuan Mianyang 621900)

This paper described a simulation study for final status survey of decommissioning site of nuclear facilities.For simplified,w e supposed that nuclide contaminated in site soil is not present in background,and radioactive nuclide concentration in soil complied with the uniform distribution in interval[o,l].Thus,we express a value of nuclide concentration as random number which belongs to uniform distribution and perform random sampling.Hereafter we used two analysis methods（parameter estimate method and non parameter statistical test（Sign Test）method）conducted a simulation to sampling process for final status survey.The simulated findings indicate that there should be a principal flow diagram of sampling process and a decision rule terminating sampling cycle.These procedures also can be appropriate for any monitoring.

关键词： decommissioning final status survey simulation.

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Study on a New Calibration Methods of in-situ HPGe γ Spectrometers used for Non-destructive Analyzing Radioactivity in Nuclear Facilities decommissioning

Study on a New Calibration Methods of in-situ HPGe γ Spectr...

引用

The Second Asian and Oceanic Congress for Radiation Protection

作者： Xiao Xuefe Song Lijun Wang Yulai Wen Fuping Ban Yin Xia Yihua Li Ruixiang Liao Haitao Li Hang Tu Xinming China Institute of Atomic Energy P.O.Box 275(24)Beijing China 102413

Non-Destructive Analysis（NDA）is one of the important techniques to determine radio-nuclides and radio-activities in radiological characterization survey of nuclear facilities decommissioning.The development of in situ gamma spectrometers,which is one kind of NDA device,over the last decade has transformed this technique once confined to laboratories into a standard technique particularly suitable for building surfaces and soil measurements,and then contamination object measurements.A number of in-situ HPGe spectrometers are available,some of which have been specifically designed for clearance measurements of buildings and sites,survey of radio-contamination term,using a collimator（thus restricting the area to be measured in order to allow quantitative measurements in Bq/cm2 or Bq/kg）.These types of detectors require extensive calibration techniques.A new calibration technique of in-situ HPGeγspectrometers used for non-destructive analyzing radioactivity in nuclear facilities decommissioning,is presented in this paper.At first,the “equivalent” geometrical sizes of the in-situ HPGe γ detector could be characterized by comparison of the detection efficiency MC modeled and experimented using a series of γ radio-sources（Energy = 121keV ～ 1.408MeV）,and adjusting the geometrical sizes of the in-situ HPGe γ detector.Second,the calibration factors of the in-situ HPGeγspectrometer,with which 50mm lead shield and a collimator installed,are obtained by computation using MC modeling code——MCNP.After then,a series of assay for some stainless steel pipes and tanks in some nuclear facilities/laboratories of CIAE are taken on site with the in-situ HPGeγspectrometer.At the same time,some examples are taken and analyzed in laboratories.The activity values obtained by in-situ HPGeγspectrometers on site are good agreement with that obtained by analyzing laboratories.The relative bias/variation between the values of activity measured by in-situ HPGeγspectrometers on site and that analyzed in laboratory is less than ±45.0%.

关键词： calibration MCNP in-situ HPGeγspectrometer characterization decommissioning

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Analysis of molten metal spreading and solidification behaviors utilizing moving particle full-implicit method

引用

Frontiers in Energy 2021年第4期15卷 959-973页

作者： Ryo YOKOYAMA Masahiro KONDO Shunichi SUZUKI Koji OKAMOTO Department of Nuclear Engineering and Management The University of Tokyo7-3-1 HongoBunkyo-kuTokyo 113-8656Japan Research Center for Computational Design of Advanced Functional materials(CD-FMat) Department of Materials and ChemistryNational Institute of Advanced Industrial Science and Technology(AIST)Central 21-1-1UmezonoTsukubaIbaraki 305-8568Japan Institute of Engineering Innovation School of EngineeringThe University of Tokyo7-3-1 HongoBunkyo-kuTokyo 113-8656Japan Nuclear Professional School The University of Tokyo2-22 ShirakataTokai-muraIbaraki 319-1188Japan

To retrieve the fuel debris in Fukushima Daiichi Nuclear Power Plants(1F),it is essential to infer the fuel debris distribution.In particular,the molten metal spreading behavior is one of the vital phenomena in nuclear severe accidents because it determines the initial condition for further accident scenarios such as molten core concrete interaction(MCCI).In this study,the fundamental molten metal spreading experiments were performed with different outlet diameters and sample amounts to investigate the effect of the outlet for spreading-solidification behavior.In the numerical analysis,the moving particle full-implicit method(MPFI),which is one of the particle methods,was applied to simulate the spreading experiments.In the MPFI framework,the melting-solidification model including heat transfer,radiation heat loss,phase change,and solid fraction-dependent viscosity was developed and implemented.In addition,the difference in the spreading and solidification behavior due to the outlet diameters was reproduced in the calculation.The simulation results reveal the detailed solidification procedure during the molten metal spreading.It is found that the viscosity change and the solid fraction change during the spreading are key factors for the free surface condition and solidified materials.Overall,it is suggested that the MPFI method has the potential to simulate the actual nuclear melt-down phenomena in the future.

关键词： molten metal spreading solidification particle method severe accident fuel debris decommissioning

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nondestructive high-sensitivity measurement method for activation estimation in accelerator room concrete

引用

辐射防护 2020年第6期40卷 677-682页

作者： Hiroshi Matsumura Go Yoshida Akihiro Toyoda Kazuyoshi Masumoto Hajime Nakamura Taichi Miura Koichi Nishikawa Kotaro Bessho Kimikazu Sasa Tetsuaki Moriguchi Fumiyoshi Nobuhara Yoko Nagashima High Energy Accelerator Research Organization(KEK) Oho 1-1Tsukuba Ibaraki 305-0801Japan University of Tsukuba 1-1-1 TennodaiTsukubaIbaraki 305-8577Japan Tokyo Nuclear Services Co. Ltd.1-3-5.TaitoTaito-kuTokyo 110-0016Japan

This study established a method for easily and quickly estimating the specific activity produced in the concrete walls and floors of accelerator rooms during long-term operation of accelerator,for advanced zoning of activated/nonactivated areas in planning the decommissioning of an accelerator.We propose a new,highly sensitive method for nondestructively estimating the specific activity in concrete that can be applied to activation zoning.In this method,instead of direct determination of the specific activities of important long-half-life radionuclides for decommissioning,such as 152 Eu and 60 Co,we determine the specific activities of short-half-life radionuclides,24 Na and 56 Mn,in situ to obtain neutron flux.The obtained neutron flux and accelerator operation history yield the specific activities of 152 Eu and 60 Co for the advance zoning of activated/non-activated concrete.This method is a powerful long-term prediction tool for concrete activation.

关键词： accelerator activation concrete specific activity decommissioning

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Evaluation of activated area in the electrostatic accelerator facilities

引用

辐射防护 2021年第2期41卷 145-150页

作者： K.Masumoto H.Matsumura T.Miura G.Yoshida A.Toyoda H.Nakamura K.Bessho T.Nakabayashi F.Nobuhara K.Sasa T.Moriguchi H.Tsuchida S.Matsuyama M.Matsuda A.Taniike High Energy Accelerator Research Organization TsukubaIbarakiJapan Japan Environmental Research Co. Ltd.ShinjukuTokyoJapan Tokyo Nuclear Service Co. Ltd.CountryTaitoTokyoJapan Univ.of Tsukuba TsukubaIbarakiJapan Kyoto Univ. UjiKyotoJapan Tohoku Univ. SendaiMiyagiJapan Japan Atomic Energy Agency TokaiNakaIbarakiJapan Kobe Univ. KobeHyogoJapan

In order to clear the activated area in electrostatic accelerator facilities,four accelerator facilities were selected and typical neutron emission experiments were performed.Neutron flux during operation and induced activity caused by charged particles on the accelerator and its surrounding area after irradiation were measured.Also the monitored neutron flux and calculated value by Monte Carlo calculation using PHITS code were compared.It was confirmed that the results between calculated data and measured data showed the good agreement with each other.Finally,it was concluded that we have to take care the activation of beam line and target.But,it is not necessary to treat accelerator tank,surrounding materials,and building concrete as radioactive materials in case of decommissioning.

关键词： Electrostatic accelerators Neutron measurement Activated area decommissioning

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

媒体词语误译举隅

引用

中国翻译 2001年第3期22卷 67-68页

作者：周学艺北京大学北京100091

现在把Bosnia译为'波斯尼亚',Bosnian译为'波斯尼亚(地区)的'较多,如:a.1991年,实际上就是他(鲍威尔)建议在科威特得到'解放'后美国迅速从伊拉克撤军,而他也曾经强烈批评美国对波斯尼亚和索马里的军事卷入.①

关键词：媒体词语英语翻译文化内涵 Bosnia decommissioning

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Clearance System for Radioactive Waste from Nuclear Facilities

Clearance System for Radioactive Waste from Nuclear Faciliti...

引用

The Second Asian and Oceanic Congress for Radiation Protection

作者： Toshiso KOSAKO The University of Tokyo Graduate School of Engineering Nuclear Professional School Shirakata-shirane 2-22 Tokai-mura Nakagun Ibaraki Japan 319-1188

A clearance concept is defined as a trivial level radioactivity containing waste from nuclear facilities. It is a kind of “exemption” concept, but applied to an exit phase of the use of radioactivity. In this paper, the original historical flow of discussions in IAEA （International Atomic Energy Agency） is reviewed. It was finalized as a document of safety guide, IAEA-RS-G.1.7 （Application of the Concepts of Exclusion, Exemption Clearance） by using 10μSv/y for each model of clearance situation. It is recommended to use internationally for the uniform guideline application of international trade. But for the application of clearance concept to the real site, the systematic approach is needed. Through the Japanese governmental specialist committee for the clearance system construction, the important key issues are discussed;the technical requirements for an operator, the governmental verifying system of clearance level checking, the positioning of reuse/recycling of these clearance materials and the social acceptance of clearance system are discussed. In this paper, these procedures are presented. And some real site examples are presented based on the power reactor decommissioning experience.

关键词： clearance radioactive waste nuclear facilities decommissioning international guideline verification system

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：