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认识ITER-1:从各国的聚变研究实验装置说起

已有 3562 次阅读 2014-9-10 14:46 |个人分类:关注的问题|系统分类:科研笔记

关注:

1) 工作中经常涉及ITER,但对其中部件构成及各部件运作过程,却不甚了解。

2)   真空室部件包含哪些部分,各部分由哪些材料构成?

3) 在等离子体环境下,真空室各部分材料会出现什么变化? 溅射粉尘的产额是多少

4) 氚在真空室各部分材料中的沉积方式、驻留机制、回收方式

5)W、不锈钢等......

6) 氚滞留量评估

 

 

    需摈弃各自为政、各单位自身利益至上的观念,应站在国家层面,联合国内各优势单位,发挥大力协同精神,共同深入推进此项研究,争创世界一流水平。

 

 

 

 

 

 

      首先这要看你的等离子体是属于什么类型的等离子体?

      依据等离子体中的重粒子温度,可以把等离子体分为两大类,热等离子体和冷等离子体。

  热等离子体中,重粒子温度为3×103 K-3×104 K,基本上达到了热力学平衡,所以具有统一的热力学温度,可以用热力学平衡状态的麦克斯韦速度分布、波尔兹曼粒子能态几率分布和沙哈方程等确定等离子体的状态和参数,例如电弧等离子体、高频等离子体即属于热等离子体由于热等离子体的高能量密度,目前主要将其用于材料合成、球化、致密以及保护性涂层的沉积。

 

   冷等离子体中重粒子温度只有室温左右,而电子温度可达上万度,所以远离热力学平衡状态,如辉光放电就属于冷等离子体。冷等离子体主要用于等离子体刻蚀、沉积以及等离子体表面修饰

   

摘自:

http://baike.baidu.com/view/1277.htm

   核聚变是解决未来能源的主要选择。高温等离子体研究以实现核聚变为目的。托卡马克类型核聚变研究是当今世界上主要聚变研究途径之一,也是本所主要学科方向。本所先后建成了HT-6B、HT-6M、HT-7和EAST等多套托卡马克核聚变实验装置及其研究系统,参与了国际热核聚变试验堆(ITER)计划与研究。计划未来在中国建造稳态燃烧托卡马克实验堆和中国磁约束聚变示范堆,进而实现纯聚变能源的商用化。
在建设托卡马克和开展等离子体物理实验研究过程中,本所发展了保障托卡马克运行的诊断、电源、微波、低温、超导、真空、数据采集处理、材料、安全与环保、电物理及精密仪器加工等一系列高新技术,开展了反应堆新概念设计和相关技术研究。在高功率电源、大型低温制冷、超导储能、高温超导、电物理装备研制等方面的技术已应用于国民经济,其中部分技术已实现产业化。

 

等离子温度:

  等离子体中电子温度 Te 多以电子伏特(eV)为单位,与温度T (以K为单位) 的关系是:将温度代入 kT,k为波尔兹曼常数,得到能量量纲,再除以1eV所代表的能量即 1.6X10^-19,即得到电子温度 Te
室温(300K)对应电子温度Te=0.026eV

电子伏特与K之间可以换算如下:
1eV=11600K

 

 

摘自百度百科:

http://baike.baidu.com/view/22214.htm?fr=aladdin

 

可行性较大的可控核聚变反应装置是托卡马克装置。
   托卡马克是一种利用磁约束来实现受控核聚变的环性容器。它的名字Tokamak 来源于环形(toroidal)、真空室(kamera)、磁(magnit)、线圈(kotushka)。
   最初是由位于苏联莫斯科的库尔恰托夫研究所的阿齐莫维齐等人在20世纪50年代发明的。
   托卡马克的中央是一个环形的真空室,外面缠绕着线圈。在通电的时候托卡马克的内部会产生巨大的螺旋型磁场,将其中的等离子体加热到很高的温度,以达到核聚变的目的
    我国也有两座核聚变实验装置。

    实现核聚变已有不少方法。最早的著名方法是"托卡马克"型磁场约束法。它是利用通过强大电流所产生的强大磁场,把等离子体约束在很小范围内以实现上述三个条件。虽然在实验室条件下已接近于成功,但要达到工业应用还差得远。要建立托卡马克型核聚变装置,需要几千亿美元。
     另一种实现核聚变的方法是惯性约束惯性约束核聚变是把几毫克的氘和氚的混合气体或固体,装入直径约几毫米的小球内。从外面均匀射入激光束或粒子束,球面因吸收能量而向外蒸发,受它的反作用,球面内层向内挤压(反作用力是一种惯性力,靠它使气体约束,所以称为惯性约束),就像喷气飞机气体往后喷而推动飞机前飞一样,小球内气体受挤压而压力升高,并伴随着温度的急剧升高。当温度达到所需要的点火温度(大概需要几十亿度)时,小球内气体便发生爆炸,并产生大量热能。这种爆炸过程时间很短,只有几个皮秒(1皮等于1万亿分之一)。如每秒钟发生三四次这样的爆炸并且连续不断地进行下去,所释放出的能量就相当于百万千瓦级的发电站。
原理上虽然就这么简单,但是现有的激光束或粒子束所能达到的功率,离需要的还差几十倍、甚至几百倍,加上其他种种技术上的问题,使惯性约束核聚变仍是可望而不可即的。
尽管实现受控热核聚变仍有漫长艰难的路程需要我们征服,但其美好前景的巨大诱惑力,正吸引着各国科学家在奋力攀登。

   

   中国新一代热核聚变装置EAST 2010年9月28日首次成功完成了放电实验,获得电流200千安、时间接近3秒的高温等离子体放电。[2] 

   负责这一项目的中国科学院等离子体所所长李建刚研究员说,此次实验实现了装置内部1亿度高温,等离子体建立、圆截面放电等各阶段的物理实验,达到了预期效果。
   EAST装置是中国耗时8年、耗资2亿元人民币自主设计、自主建造而成的。
   美、法等国在20世纪80年代中期发起了耗资46亿欧元的国际热核实验反应堆(ITER)计划,旨在建立世界上第一个受控热核聚变实验反应堆,为人类输送巨大的清洁能量。这一过程与太阳产生能量的过程类似,因此受控热核聚变实验装置也被俗称为“人造太阳”。[3] 
   中国于2003年加入ITER计划。位于安徽合肥的中科院等离子体所是这个国际科技合作计划的国内主要承担单位,其研究建设的EAST装置稳定放电能力为创记录的1000秒,超过世界上所有正在建设的同类装置。
 
    EAST大科学工程总经理万元熙教授说,与ITER相比,EAST在规模上小很多,但两者都是超导非圆截面托卡马克,即两者的等离子体位形及主要的工程技术基础是相似的,而EAST至少比ITER早投入实验运行10至15年。

 

 

 

 

 

 

维基百科:
 
 

  如果要进行核聚变反应,首先就必须提高物质的温度,使原子核和电子分开,处于这种状态的物质称为“等离子体”﹝plasma﹞。     顾名思义,核力是一种非常强大的力量,而其力量所及的范围仅止于10^(-10)~10^(-13 )米左右,当质子和中子互相接近至此范围时,核力就会发挥作用,因而发生核聚变反应。

    但由于原子核带正电,彼此间会互相排斥,所以很难使其彼此互相接近。若要克服其相斥的力量,就必须适当地控制等离子体的温度密度封闭时间﹝维持时间﹞,此三项条件缺一不可。由于提高物质的温度可以使原子核剧烈转动,因此温度升高,密度变大,封闭的时间越长,彼此接近的机会越大。

    由于等离子体很快就会飞散开来,所以必须先将其封闭。用来使等离子体封闭的方法有许多种,太阳内部是利用巨大引力使等离子体封闭,而在地球上则必须采取别的方法,磁场的利用便是其中一种。当等离子体带电时,电荷被卷在磁力线上,因此只要制造出磁场,就能够将等离子体封闭,使它们悬浮在真空

附:各国的聚变研究实验装置

摘自Wikipedia

Fusion experimental devices by confinement method

 

 

 

Tore Supra is a French tokamak that began operating after the discontinuation of TFR (Tokamak of Fontenay-aux-Roses) and of Petula (in Grenoble).

 

Its name comes from the words torus and superconductor, as Tore Supra was for a long time the only tokamak of this size with superconducting toroidal magnets, allowing the creation of a strong permanent toroidal magnetic field.

 

Tore Supra is situated at the nuclear research center of Cadarache, Bouches-du-Rhône in Provence, one of the sites of the Commissariat à l'Énergie Atomique. It started operation in 1988. It has a goal of creating long-duration plasma; it now holds the record of the longest plasma duration time for a tokamak (6 minutes 30 seconds and over 1000 MJ of energy injected and extracted in 2003), and it allows to test critical parts of equipment such as plasma facing wall components or superconducting magnets that will be used in its successor, ITER.

Device parameters[edit]
  • Major plasma radius: 2.25 m

  • Minor plasma radius: 0.70 m

  • Toroidal magnetic field on the center of the plasma core: 4.5 T

  • Plasma current: 1.7 MA

  • Longest plasma discharge (predicted): 1000 s

  • Auxiliary plasma heating (ion and electron cyclotron resonance heating and lower hybrid current drive): 20 MW

External links[edit]

 

 

Tokamak Fusion Test Reactor
From Wikipedia, the free encyclopedia
TFTR
TFTR in 1989
TypeTokamak
Operation date1982–1997
Major radius2.1–3.1 m
Minor Radius0.4–0.96 m
Magnetic field6.0 T (toroidal)
Heating51 MW
Plasma current3.0 MA

The Tokamak Fusion Test Reactor (TFTR) was an experimental tokamak built at Princeton Plasma Physics Laboratory (in Princeton, New Jersey) circa 1980.

  Following on from the PDX (Poloidal Diverter Experiment) and PLT (Princeton Large Torus) devices, it was hoped that TFTR would finally achieve fusion energy break-even.

Unfortunately, the TFTR never achieved this goal. However it did produce major advances in confinement time and energy density, which ultimately contributed to the knowledge base necessary to build ITER. TFTR operated from 1982 to 1997.

In 1986 it produced the first 'supershots' which produced many more fusion neutrons.[1]

In 1994 it produced a then world-record 10.7 megawatts of fusion power from a plasma composed of equal parts of deuterium and tritium (exceeded at JET in the UK, which generated 16MW for 22MW input in 1997, which is the current record).

It was followed by the NSTX spherical tokamak.

References[edit]
  1. Jump up ^Fusion. Robin Herman. 1990. ISBN 0-521-38373-0

See alJoint European Torus

JET, the Joint European Torus, is a magnetic confinementplasma physics experiment located in Oxfordshire, UK. It is currently the largest facility of its kind in operation. Its main purpose is to open the way to future nuclear fusion experimental tokamak reactors such as ITER and DEMO.

 

 

Construction[edit]

The JET facilities are situated on a former Navy airfield near Culham, Oxfordshire – RNAS Culham (HMS Hornbill), in the UK. The construction of the buildings which house the project was undertaken by Tarmac Construction,[1] starting in 1978 with the Torus Hall being completed in January 1982. Construction of the JET machine itself began immediately after the completion of the Torus Hall, with the first plasma experiments in 1983.

The components for the JET machine came from manufacturers all over Europe, with these components transported to the site.

Because of the extremely high power requirements for the tokamak, and the fact that power draw from the main grid is limited, two large flywheel generators were constructed to provide this necessary power. Each 775 ton flywheel can spin up to 225 rpm.[2] One generator provides power for the 32 toroidal field coils, the other for inner poloidal field coils. The outer field coils draw their power from the grid.

Timeline[edit]

(Source[3])

  • 1973 - Beginning of design work

  • 1977 - Culham site is chosen and the construction work begins

  • 25 June 1983 - Very first plasma achieved at JET

  • 9 April 1984 - JET officially opened by Her Majesty Queen Elizabeth II

  • 9 November 1991 - The world’s first controlled release of fusion energy

  • 1993 - JET converted to Divertor configuration

  • 1997 - JET produces 16 megawatts of fusion power (world record)

  • 1998 - Remote Handling first used for in-vessel work

  • 2000 - The collective use of JET and its scientific programme becomes managed through the European Fusion Development Agreement (EFDA)

  • 2006 - JET starts operation with ITER-like magnetic configurations

  • 2009-2011 Installation of the ITER-Like Wall

Operating history[edit]

In 1970 the Council of the European Community decided in favour of a robust fusion programme and provided the necessary legal framework for a European fusion device to be developed.[3] Three years later, the design work began for the JET machine. In 1977 the construction work began and at the end of the same year a former Fleet Air Arm airfield at Culham in the UK was selected as the site for the JET project. In 1978 the "JET Joint Undertaking" was established as a legal entity. Only five years later the construction was completed on time and on budget. On 25 June 1983 the very first JET plasma was achieved and on 9 April 1984 Her Majesty Queen Elizabeth II officially opened this European fusion experiment.

In the history of fusion research the year 1991 is particularly significant: on the 9th November a Preliminary Tritium Experiment achieved the world’s first controlled release of fusion power. Six years later, in 1997, another world record was achieved at JET: 16 mega watts of fusion power were produced from a total input power of 24 mega watts – a 65% ratio. This is equivalent to a release of 22 mega joules of energy. a total of 16 MW was measured for less than a second and 5 MW for 5 seconds.

A “Remote Handling” system is, in general, an essential tool for any subsequent fusion power plant and especially for the future experimental reactor, ITER. In 1998 JET’s engineers developed a remote handling system with which, for the first time, it was possible to exchange certain components using artificial hands only.

In 1999 the European Fusion Development Agreement (EFDA) was established with responsibility for the future collective use of JET. With the turn of the millennium the "Joint Undertaking" ended and the JET Facilities commenced operating under contract by CCFE (at that time UKAEA). From then, JET’s scientific programme was determined by EFDA. The sturdiness and flexibility of JET’s original design has made it possible for the device to evolve with the interests of the fusion community and meet the requirements of ITER. JET was converted to Divertor configuration in 1993 and started operation with ITER-like magnetic configurations in 2006. From October 2009 to May 2011 the ITER-Like Wall was installed.

JET was originally set up by Euratom with a discriminatory employment system that allowed non-British staff to be employed at more than twice the salaries of their British equivalents. The British staff eventually had this practice declared illegal, and substantial damages were paid at the end of 1999 to UKAEA staff (and later to some contractors). This was the immediate cause of the ending of Euratom's operation of the facility.

In December 1999, JET's international contract ended and the United Kingdom Atomic Energy Authority (UKAEA) then took over managing the safety and operation of the JET facilities on behalf of its European partners. From that time (2000), JET's experimental programme was then co-ordinated by the European Fusion Development Agreement (EFDA) Close Support Unit.

JET operated throughout 2003, with the year culminating in experiments using small amounts of tritium. For most of 2004, JET was shut down for a series of major upgrades, increasing its total available heating power to over 40 MW, enabling further studies relevant to the development of ITER to be undertaken. In late September 2006, the C16 experimental campaign was started, with the objective of studying ITER-like operation scenarios.

In October 2009, a 15-month shutdown period was started, and improvements were made to the tokamak, including replacing carbon components in the vacuum vessel with tungsten and beryllium ones, to bring JET's components more in line with those planned for ITER. Heating power was also increased by 50%, bringing the neutral beam power available to the plasma up to 34MW, and diagnostic and control capabilities were improved. In total, over 86,000 components were changed in the torus during the shutdown.

In mid-May 2011, the shutdown reached its end.[4] The first experimental campaign after the installation of the “ITER-Like Wall” started on 2 September 2011.[5]

Equipment capability[edit]

JET is equipped with remote handling facilities[6] to cope with the radioactivity produced by deuterium-tritium (D-T) fuel, which is the fuel proposed for the first generation of fusion power plants. Pending construction of ITER, JET remains the only large fusion reactor with facilities dedicated to handling the radioactivity released from D-T fusion. The power production record-breaking runs from JET and TFTR used 50–50 D-T fuel mixes.

During a full D-T experimental campaign in 1997 JET achieved a world record peak fusion power of 16 MW which equates to a measured gain Q, of approximately 0.7. Q is the ratio of fusion power produced to input heating power. In order to achieve break-even, a Q value greater than 1 is required. A self-sustaining burning plasma requires at least Q=5 (since the alpha particles carry one fifth the fusion energy) and a power plant requires at least Q=10.[7] As of 1998, a higher Q of 1.25 is claimed for the JT-60tokamak; however, this was not achieved under real D-T conditions but extrapolated from experiments performed with a pure deuterium (D-D) plasma. Similar extrapolations have not been made for JET, but it is likely that increases in Q over the 1997 measurements could now be achieved if permission to run another full D-T campaign was granted. Work has now begun on ITER to further develop fusion power.

Machine information[edit]
Internal view of the JET tokamak superimposed with an image of a plasma taken with a visible spectrum video camera.
  • Weight of the vacuum vessel: 100 tonnes

  • Weight of the toroidal field coils: 384 tonnes

  • Weight of the iron core: 2800 tonnes

  • Wall material: Entirely Beryllium save Tungsten 'exhaust'

  • Plasma major radius: 2.96 m

  • Plasma minor radius: 2.10 m (vertical), 1.25 m (horizontal)

  • Flat top pulse length: 20–60 s

  • Toroidal magnetic field (on plasma axis): 3.45 T

  • Plasma current: 3.2 MA (circular plasma), 4.8 MA (D-shape plasma)

  • Lifetime of the plasma: 5–30 s

  • Auxiliary heating:

     

     

  • Major diagnostics:

    • Visible/infrared video cameras

    • Numerous magnetic coils – provide magnetic field, current and energy measurements

    • Thomson scattering spectroscopy – provides electron temperature and electron density profiles of the plasma

    • Charge exchange spectroscopy – provides impurity ion temperature, density and rotation profiles

    • Interferometers – measure line integrated plasma density

    • Electron cyclotron emission antennas – fast, high resolution electron temperature profiles

    • Visible/UV/X-rayspectrometers – temperatures and densities

    • Neutron diagnostics:

      • Neutron counting: Number of neutrons leaving the plasma relates directly to the fusion power.

      • Neutron spectroscopy – Neutron energy relates to the ion velocity distribution and hence the fuel reactivity.

       

       

    • Bolometers – energy loss from the plasma

    • Various material probes – inserted into the plasma to take direct measurements of flow rates and temperatures

    • Soft X-ray cameras to examine MHD properties of plasmas

    • Time resolved neutron yield monitor

    • Hard X-ray monitors

    • Electron Cyclotron Emission Spatial Scanners

     

     

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