Source of thermonuclear neutrons «Jupiter NS»
The project on a plasma source of neutrons for technological tests of thermonuclear reactor materials is considered. The basis of the project is the multislit electromagnetic trap with axial symmetric magnetic field geometry. The results of electromagnetic trap «Jupiter 2» calculations were used as...
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| Date: | 2003 |
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2003
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| Cite this: | Source of thermonuclear neutrons «Jupiter NS» / O.A. Lavrent’ev // Вопросы атомной науки и техники. — 2003. — № 1. — С. 30-32. — Бібліогр.: 5 назв. — англ. |
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| citation_txt | Source of thermonuclear neutrons «Jupiter NS» / O.A. Lavrent’ev // Вопросы атомной науки и техники. — 2003. — № 1. — С. 30-32. — Бібліогр.: 5 назв. — англ. |
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| description | The project on a plasma source of neutrons for technological tests of thermonuclear reactor materials is considered. The basis of the project is the multislit electromagnetic trap with axial symmetric magnetic field geometry. The results of electromagnetic trap «Jupiter 2» calculations were used as initial data. It is predicted that the source will be able to produce 8*10¹⁸ n/s with the flux density 10¹⁴ n/cm²s onto the surface of samples under irradiation with tritium expenditure of 4*10⁻⁵g/s
Розглянуто проект плазмового джерела нейтронів для технологічних випробувань матеріалів термоядерного реактору. В основу проекту покладена електромагнітна пастка з осесиметричною геометрією магнітного поля. В якості вихідних даних використовувались результати розрахунків електромагнітної пастки ”Юпітер 2”. При затратах 4*10⁻⁵ г/с тритію джерело спроможне виробляти 8*10¹⁸ н/с з флюенсом 10¹⁴ н/см²с на поверхні опромінюваних зразків.
Рассмотрен проект плазменного источника нейтронов для технологических испытаний материалов термоядерного реактора. В основу проекта положена многощелевая электромагнитная ловушка с осесимметричной геометрией магнитного поля. В качестве исходных данных использовались результаты расчетов электромагнитной ловушки “Юпитер 2”. При расходе 4*10⁻⁵ г/с трития источник способен производить 8*10¹⁸ н/с с флюэнсом 10¹⁴ н/см²с на поверхности облучаемых образцов.
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SOURCE OF THERMONUCLEAR NEUTRONS «JUPITER NS»
O.A.Lavrent’ev
Institute of Plasma Physics, National Scientific Center «Kharkiv Institute
of Physics and Technology», 61108, Kharkiv, Ukraine
The project on a plasma source of neutrons for technological tests of thermonuclear reactor materials is considered. The
basis of the project is the multislit electromagnetic trap with axial symmetric magnetic field geometry. The results of
electromagnetic trap «Jupiter 2» calculations were used as initial data. It is predicted that the source will be able to
produce 8*1018 n/s with the flux density 1014 n/cm2s onto the surface of samples under irradiation with tritium
expenditure of 4*10-5g/s.
PACS: 52.55.-s
INTRODUCTION
The most important criterion of efficiency of a plasma
source of the thermonuclear neutrons is a tritium
expenditure refereed to a quantity of neutrons being
produced. For two-component source, where neutrons are
created as a result of injection of high energetic tritium
beams into a deuterium plasma target, this expenditure is
determined by energy of injected tritium ions and
parameters of a target plasma. For example, in the neutron
source GDT-NS [1] an injection of beam of tritium atoms
with 94 keV energy and equivalent current 69.1A into a
target plasma with parameters ne =2*1014 D+/cm3, Te =
1.1keV and Ti = 0.3keV, the neutron yield will be 1018 n/s
with the tritium injection rate 2*10-3g/s. Of this value only
5*10-6g/s will be spent for the production of neutrons and
all other quantity of injected tritium will leave the trap
through axial holes together with deuterium plasma flow.
Thus the efficiency of tritium use in GDT-NS is not more
than 0.25% of the full-injected flow. The tritium
extraction from deuterium-tritium plasma for repeated use
is a problem which does not yield on the complexity and
cost to its production in a nuclear reactor. The increase of
energy of injected tritium atoms up to 300keV and the
electron target temperature up to 10keV would allow to
increase efficiency of tritium use up to 2.5% and to lower
the tritium expenditure in the GDT-NS on the order in
magnitude. But at the temperature 10keV the plasma
target becomes to be an intensive source of neutrons
itself, i. e. the problem of decreasing the tritium
expenditure is reduced to achievement of thermonuclear
plasma parameters in the installations of comparatively
small sizes under Q<<1. The multislit electromagnetic
trap can be used as one of such installations [2].
DESCRIPTION OF INSTALLATION
Installation «Jupiter NS» represents multislit
electromagnetic trap with axial-symmetric magnetic field
geometry. The scheme of installation is presented in fig. 1.
Magnetic system consists of three groups of co-axial coils
located on an axis of a cylinder. The coils of the first group
form a central part of the installation. They have alternated
polarity of current switching on and create the layer of space-
periodic magnetic field along the cylindrical surface of a
central part. The coils of second group join the central part at
both sides. These coils are intended to conjugate the space-
periodic field of the central part with a field of axial
magnetic mirrors. The coils of magnetic mirrors form a third
group.
Fig.1. «Jupiter - NS» scheme: 1 - magnetic field coils,
2 - support frame, 3 - helium pumps, 4 - vacuum
chamber,
5 - magnetic slits
They are located in pairs at the ends of magnetic system.
All coils are placed in a vacuum-tight casing and fixed on
the common support frame. The coils and the support
frame are placed inside a vacuum volume, which is
pumped out by helium condensation pumps. The sizes of
magnetic system: an internal diameter 2R = 1.34m, the
length between axial holes L = 4m. The value of magnetic
field in the ring magnetic slits BA = 5T and in the axial
holes BA0 = 10T. Magnetic field configuration is
characterized by deep magnetic well with an
unmagnetized plasma volume Vp =2m3.
Ring magnetic slits and axial holes are closed by
electrostatic mirrors, i.e., by electrodes with a high
negative potential applied to them. The electrostatic
system, fig. 2, is assembled on a rigid supporting skeleton
and is inserted, as a whole, between coils. Special devices
allow adjusting a plane of every ring slit with the plane of
symmetry of a magnetic field while assembling. Anode
diaphragms and external ring electrodes are under potential
close to the ground potential and medium electrodes - under
a high negative potential. It allows to distribute a high-
voltage loading on several vacuum intervals between
30 Problems of Atomic Science and Technology. 2003. № 1. Series: Plasma Physics (9). P. 30-32
electrodes and thus to make easier the conditions of
achievement of the high negative potentials.
Fig. 2. The system of electrostatic close of magnetic slits:
1 - magnetic field coils, 2 - vacuum-tight casing of coils,
3 - support frame, 4 - high voltage electrodes, 5 -
insulators, 6 - anode diaphragms, 7 - radiating cover
PARAMETERS OF NEUTRON SOURCE
Magnetic field of 5T allows to have a plasma with
parameters: ne = 2*1014cm-3, Te,i = 20keV in the
electromagnetic trap. Ousting a weak magnetic field from
the central part, plasma is confined by a boundary
magnetic surface with B0 = [8πn(Te+Ti)]1/2 = 1.8T. The
longitudinal plasma confinement in magnetic slits is
executed by electrical fields. Potential Φk, enclosed to
electrodes of electrostatic system, fig. 3, creates a
potential barrier Φe for electrons, and a negative
volumetric plasma charge creates a potential well with
depth Φp and a potential barrier Φi for ions. The flow of
electrons, circulating through magnetic slits, causes
depression of potential ∆Φ, lowering height of potential
barriers.
To make the electrostatic confinement of plasma
effective the condition ∆Φ<<Φp should be satisfied. Using
theoretical calculations [3] we can find the flow of
electrons F=1.5*1024s-1, circulating through the magnetic
slit. This flow creates a volumetric electron density nA =
2.18*1012cm-3 and the potential depression ∆Φ = 19.7kV
in an anode slit of 2a = 0.2cm in width. Values of
potential barriers Φe and Φi are determined by the balance
of the charged particle flows arriving into the trap and
leaving it.
Electrons arrive into the trap in consequence of
injection through axial holes and neutral gas ionization,
and leave the trap in consequence of diffusion across a
magnetic field (in the coordinate space) and diffusion
along magnetic field lines (in the velocity space). We
shall evaluate the diffusion flow in the coordinate space
using results of theoretical calculations [4]:
Fig. 3. The scheme of electrostatic closing of magnetic
slits: Φk - potential, enclosed to electrodes of
electrostatic system, Φe - potential barrier for electrons,
Φp - potential well depth, Φi - potential barrier for ions,
∆Φ -depression of potential
Ie⊥ = DeiR2ne0(6Fc+Fk) = 6.23*1020/s (=99.7A) (1)
The electron diffusion flow in the velocity space is [5]:
Ie = ne0Vp/[(πγe)1/2τsl exp(γe)] (2)
where τsl is a lifetime of electrons in the trap at absence of
a electrostatic confinement, when γe= Φe/Te.
Ions arrive into the trap in consequence of neutral gas
ionization and leave it in consequence of diffusion in the
velocity space and due to thermonuclear reactions. The
diffusion flow of ions is determined by the rate of
maxwellization of particles as a result of Coulomb
collisions:
Ii = 4(2π)1/2e4λne0
2Vp/mi
1/2Ti
3/2exp(γi) (3)
where γi = Φi/Ti. The flow of particles - the products of
thermonuclear reactions is:
If = 0.5σf vi ni
2
Vp = 1.68*1019 /s (=2.69A) (4)
From the condition of a charge balance
Ie⊥ + Ie =Ii +Ik + If (5)
we find the values of potential barriers Φe and Φi. For the
potential Φk = 300kV and electron injection current eIk =
15A, these values are: Φe = 185.4kV, Φi = 94.9kV.
Accordingly, Ie = 31A, Ii = 113.1A.
In the electromagnetic trap the principle of energy
recuperation can be realized. Leaving the trap through
potential barrier, charged particles loose only overbarrier
additive portion of energy without return. It is determined
by a ratio of particle maxwellization rate to the rate of
their escaping from the trap through magnetic slits. For
ions the time of maxwellization τm exceeds the time τsl of
particle escape from the trap through the slits, thus the
31
overbarrier additive is small. For electrons, on the
contrary, τsl>>τm and electrons have enough time to
acquire the Maxwellian distribution before escaping from
the trap. The overbarrier additive for electron is close to
the maximum value 2Te. The electrons, diffusing across a
magnetic field are spreading their kinetic energy,
acquiring in electrical field, when collide with ions.
They transfer energy of the order of Te to the anode
diaphragms. The rates of energy losses through diffusion
channels are: Pe⊥=1.99MW, Pe=1.07MW, Pi=1.24 MW.
The bremsstrahlung radiation loss in hydrogen plasma Pr
= 0.191MW. The whole energy losses from plasma are: P
Σ = 4.5MW. This energy losses have to be compensated
by electron injection Pk = IekΦk = 4.5MW. The energy
lifetime can be estimated as: τe = 0.57s.
The equicomponent mixture of deuterium and tritium
of a value 2.6*10-3g/s must be injected into a plasma for
maintaining the neutron flux 8*1018n/s. The tritium
expenditure for neutron production is 4*10-5g/s. The spent
gas mixture arrives into a vacuum chamber, where
deuterium and tritium are collected by a special cryogenic
pump-accumulator, for repeated use in the neutron source.
An opportunity to provide the complex technological tests
of materials in conditions close to conditions of a real
thermonuclear reactor should be related to merits of
neutron source of a given type.
REFERENCES
1.A.A. Ivanov, I.A. Kotelnikov, E.P. Kruglyakov,
V.I. Volosov, V.V. Mirnov, D.D. Ryutov,
Yu.A.Tsidulko, Yu.N. Yudin, A.M. Astarcovich,
V.G.Krasnoperov. A plasma -type neutron source for
fusion material irradiation // Proc. of the 17th Symp
Fusion Technology. Rome 14 - 18.09.1992/ Pergamon
Press. Oxford, 1992, p. 1394 - 1398.
2.T.J. Dolan. Magnetic electrostatic plasma confinement
// Plasma Physics and Controlled
Fusion.(36),1994,p.1539-1593.
3.A.S. Kaye. Adiabatic cusp losses/ CLM, 1969 p. 193.
4.S.V. Germanova , O.A. Lavrent’ev, V.I. Petrenko.
Crossfield transport of electrons in a multicusp
electromagnetic trap// Voprosy atomnoj nayki i
techniki. Termojadernyj sintez. N2,1991,p. 74 (in
Russian).
5.E.E. Jushmanov. Injection of charged particles into
magneto - electrostatic trap.// Fizika Plasmy. N4,1978,
p.23 (in Russian).
ДЖЕРЕЛО ТЕРМОЯДЕРНИХ НЕЙТРОНІВ «JUPITER NS»
О. О. Лаврентьєв
Розглянуто проект плазмового джерела нейтронів для технологічних випробувань матеріалів термоядерного
реактору. В основу проекту покладена електромагнітна пастка з осесиметричною геометрією магнітного поля.
В якості вихідних даних використовувались результати розрахунків електромагнітної пастки ”Юпітер 2”. При
затратах 4⋅10-5 г/с тритію джерело спроможне виробляти 8⋅1018 н/с з флюенсом 1014 н/с на поверхні
опромінюваних зразків.
ИСТОЧНИК ТЕРМОЯДЕРНЫХ НЕЙТРОНОВ «JUPITER NS»
О. А. Лаврентьев
Рассмотрен проект плазменного источника нейтронов для технологических испытаний материалов
термоядерного реактора. В основу проекта положена многощелевая электромагнитная ловушка с
осесимметричной геометрией магнитного поля. В качестве исходных данных использовались результаты
расчетов электромагнитной ловушки “Юпитер 2”. При расходе 4⋅10-5 г/с трития источник способен производить
8⋅ 1018 н/с с флюэнсом 1014 н/см2с на поверхности облучаемых образцов.
32
INTRODUCTION
DESCRIPTION OF INSTALLATION
PARAMETERS OF NEUTRON SOURCE
REFERENCEs
О. О. Лаврентьєв
О. А. Лаврентьев
|
| id | nasplib_isofts_kiev_ua-123456789-110337 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 1562-6016 |
| language | English |
| last_indexed | 2025-12-07T15:48:13Z |
| publishDate | 2003 |
| publisher | Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| record_format | dspace |
| spelling | Lavrent’ev, O.A. 2017-01-03T14:04:44Z 2017-01-03T14:04:44Z 2003 Source of thermonuclear neutrons «Jupiter NS» / O.A. Lavrent’ev // Вопросы атомной науки и техники. — 2003. — № 1. — С. 30-32. — Бібліогр.: 5 назв. — англ. 1562-6016 PACS: 52.55.-s https://nasplib.isofts.kiev.ua/handle/123456789/110337 The project on a plasma source of neutrons for technological tests of thermonuclear reactor materials is considered. The basis of the project is the multislit electromagnetic trap with axial symmetric magnetic field geometry. The results of electromagnetic trap «Jupiter 2» calculations were used as initial data. It is predicted that the source will be able to produce 8*10¹⁸ n/s with the flux density 10¹⁴ n/cm²s onto the surface of samples under irradiation with tritium expenditure of 4*10⁻⁵g/s Розглянуто проект плазмового джерела нейтронів для технологічних випробувань матеріалів термоядерного реактору. В основу проекту покладена електромагнітна пастка з осесиметричною геометрією магнітного поля. В якості вихідних даних використовувались результати розрахунків електромагнітної пастки ”Юпітер 2”. При затратах 4*10⁻⁵ г/с тритію джерело спроможне виробляти 8*10¹⁸ н/с з флюенсом 10¹⁴ н/см²с на поверхні опромінюваних зразків. Рассмотрен проект плазменного источника нейтронов для технологических испытаний материалов термоядерного реактора. В основу проекта положена многощелевая электромагнитная ловушка с осесимметричной геометрией магнитного поля. В качестве исходных данных использовались результаты расчетов электромагнитной ловушки “Юпитер 2”. При расходе 4*10⁻⁵ г/с трития источник способен производить 8*10¹⁸ н/с с флюэнсом 10¹⁴ н/см²с на поверхности облучаемых образцов. en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Вопросы атомной науки и техники Magnetic confinement Source of thermonuclear neutrons «Jupiter NS» Джерело термоядерних нейтронів «Jupiter NS» Источник термоядерных нейтронов «Jupiter NS» Article published earlier |
| spellingShingle | Source of thermonuclear neutrons «Jupiter NS» Lavrent’ev, O.A. Magnetic confinement |
| title | Source of thermonuclear neutrons «Jupiter NS» |
| title_alt | Джерело термоядерних нейтронів «Jupiter NS» Источник термоядерных нейтронов «Jupiter NS» |
| title_full | Source of thermonuclear neutrons «Jupiter NS» |
| title_fullStr | Source of thermonuclear neutrons «Jupiter NS» |
| title_full_unstemmed | Source of thermonuclear neutrons «Jupiter NS» |
| title_short | Source of thermonuclear neutrons «Jupiter NS» |
| title_sort | source of thermonuclear neutrons «jupiter ns» |
| topic | Magnetic confinement |
| topic_facet | Magnetic confinement |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/110337 |
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