Modeling of radiation and thermal-hydraulic characteristics of the converter-target under irradiation with electrons in order to optimize isotope ⁹⁹mTc production
The method of the modeling of radiation and thermal-hydraulic characteristics of the system for ⁹⁹mTc isotope production was developed, using the Monte Carlo method for computation of radiation fields and computational fluid dynamics for modeling of thermal-hydraulic characteristics. The three-dimen...
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| Published in: | Вопросы атомной науки и техники |
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| Date: | 2013 |
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| Format: | Article |
| Language: | English |
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2013
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| Online Access: | https://nasplib.isofts.kiev.ua/handle/123456789/112092 |
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| Journal Title: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Cite this: | Modeling of radiation and thermal-hydraulic characteristics of the converter-target under irradiation with electrons in order to optimize isotope ⁹⁹mTc production / Ye.V. Rudychev, S.I. Prokhorets, D.V. Fedorchenko, M.A. Khazhmuradov // Вопросы атомной науки и техники. — 2013. — № 6. — С. 214-219. — Бібліогр.: 6 назв. — англ. |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine| _version_ | 1860256339564953600 |
|---|---|
| author | Rudychev, Ye.V. Prokhorets, S.I. Fedorchenko, D.V. Khazhmuradov, M.A. |
| author_facet | Rudychev, Ye.V. Prokhorets, S.I. Fedorchenko, D.V. Khazhmuradov, M.A. |
| citation_txt | Modeling of radiation and thermal-hydraulic characteristics of the converter-target under irradiation with electrons in order to optimize isotope ⁹⁹mTc production / Ye.V. Rudychev, S.I. Prokhorets, D.V. Fedorchenko, M.A. Khazhmuradov // Вопросы атомной науки и техники. — 2013. — № 6. — С. 214-219. — Бібліогр.: 6 назв. — англ. |
| collection | DSpace DC |
| container_title | Вопросы атомной науки и техники |
| description | The method of the modeling of radiation and thermal-hydraulic characteristics of the system for ⁹⁹mTc isotope production was developed, using the Monte Carlo method for computation of radiation fields and computational fluid dynamics for modeling of thermal-hydraulic characteristics. The three-dimensional solid models of this system were developed, where system geometry was fully described and necessary initial conditions was taking into account. We considered the isotope ⁹⁹Mo production due to the (γ, n) and (n, γ) reactions and analyzed the efficiency of these reactions. To improve the efficiency of the isotope ⁹⁹Mo production and to reduce the energy deposition in the target material it is proposed to use the composite converter made of Pb + Al, Pb + Cu, Pb + Be, for which the optimal parameters were defined. Application of this method makes it possible to optimize the performance of the system for ⁹⁹mTc isotope production.
Розроблено методику розрахунків моделювання радіаційних та термогідравлічних характеристик системи отримання ізотопу ⁹⁹mTc, яка використовує метод Монте-Карло для радіаційних полів системи і метод обчислювальної гідродинаміки для термогідравлічних характеристик системи. Створено тривимірні твердотільні моделі системи, які повністю описують геометрію системи та враховують необхідні початкові умови. Розглянуто напрацювання ізотопу ⁹⁹Mo за рахунок (γ, n)- і (n, γ)-реакцій та проведено аналіз їх ефективності. Для підвищення ефективності напрацювання ізотопу ⁹⁹Mo та зменшення енерговиділення в матеріалі мішені запропоновано використовувати композитний конвертер типу Pb+Al, Pb+Cu, Pb+Be, для якого визначено оптимальні параметри. Застосування методики дає можливість оптимізувати експлуатаційні характеристики системи отримання ізотопу ⁹⁹mTc.
Разработана методика расчетов моделирования радиационных и термогидравлических характеристик системы получения изотопа ⁹⁹mTc, использующая метод Монте-Карло для радиационных полей системы и метод вычислительной гидродинамики для термогидравлических характеристик системы. Созданы трехмерные твердотельные модели системы, полностью описывающие геометрию системы и учитывающие необходимые начальные условия. Рассмотрена наработка изотопа ⁹⁹Mo за счет (γ, n)- и (n, γ)-реакций и проведен анализ их эффективности. Для повышения эффективности наработки изотопа ⁹⁹Mo и уменьшения энерговыделения в материале мишени предложено использовать композитный конвертер типа Pb+Al, Pb+Cu, Pb+Be, для которого определены оптимальные параметры. Применение методики дает возможность оптимизировать эксплуатационные характеристики системы получения изотопа ⁹⁹mTc.
|
| first_indexed | 2025-12-07T18:49:50Z |
| format | Article |
| fulltext |
ISSN 1562-6016. ВАНТ. 2013. №6(88) 214
MODELING OF RADIATION AND THERMAL-HYDRAULIC
CHARACTERISTICS OF THE CONVERTER-TARGET UNDER
IRRADIATION WITH ELECTRONS IN ORDER TO OPTIMIZE
ISOTOPE 99mTc PRODUCTION
Ye.V. Rudychev, S.I. Prokhorets, D.V. Fedorchenko, M.A. Khazhmuradov
National Science Center "Kharkov Institute of Physics and Technology", Kharkov, Ukraine
E-mail: khazhm@kipt.kharkov.ua
The method of the modeling of radiation and thermal-hydraulic characteristics of the system for 99mTc isotope
production was developed, using the Monte Carlo method for computation of radiation fields and computational
fluid dynamics for modeling of thermal-hydraulic characteristics. The three-dimensional solid models of this system
were developed, where system geometry was fully described and necessary initial conditions was taking into ac-
count. We considered the isotope 99Mo production due to the (γ, n) and (n, γ) reactions and analyzed the efficiency
of these reactions. To improve the efficiency of the isotope 99Mo production and to reduce the energy deposition in
the target material it is proposed to use the composite converter made of Pb + Al, Pb + Cu, Pb + Be, for which the
optimal parameters were defined. Application of this method makes it possible to optimize the performance of the
system for 99mTc isotope production.
PACS: 24.10Lx, 29.25Rm, 61.80.Ed, 87.53Wz, 87.58Ji
INTRODUCTION
Now the clinical diagnosis of human diseases by in-
troducing to his body the radioisotopes as the indicators
is being developed. These substances are called radio-
pharmaceuticals (RFP). The main objective while the
production of radiopharmaceuticals is obtaining the
necessary isotopes, for example, 99mTc − it radiophar-
maceuticals are used for the diagnosis of diseases of
nearly all the human major organs and are used in
80…85% of diagnostic procedures with labeled atoms.
In the U.S. the number of treatments with drugs on the
basis of 99mTc reaches 12 million per year. The annual
world market for 99mTc is estimated at 3.7 billion dol-
lars. High needs in 99mTc come from its relatively short
half-life − 6.02 h and low gamma-radiation energy −
0.1405 MeV. These factors provide low exposure dose
(0.5…5% of the allowable level) and at the same high
penetration capability for radiometric measurements.
Therefore, obtaining 99Mo isotope, which transforms
through its beta-decay (T1/2 = 2.748 days) to the isotope
99mTc, plays an important role in nuclear medicine. [1]
The traditional method of producing 99Mo in nuclear
reactors is technically and environmentally difficult.
The alternative methods of producing 99Mo at the
charged particle accelerators was proposed at KIPT, and
researches on obtaining 99Mo nuclide from the reactions
100Mo(γ, n)99Mo (bremsstrahlung), 98Mo (n, γ)99Mo
(Photonuclear neutrons from bremsstrahlung) were done
using a linear high-current electron accelerator. The
experimental facility was developed on the basis of the
acceleration stand LU-20 (20 MeV, 10 kW), and 99Mo
was produced by irradiation for 10 hours of molyb-
denum target of natural isotopic composition [2].
To obtain high-energy photons at the electron accel-
erator it is necessary to use converters from materials
that have a high conversion rate of electrons in the pho-
tona (tantalum, lead). The intensity of the obtained pho-
tons depends on electron beam energy, and at the same
power the system with greater energy will be more ef-
fective. So, it is more preferable to use stand based on
the accelerator KUT-30 with electron energy
27…40 MeV [3]
To maximize the amount of the 99Mo isotope it is
necessary to ensure optimum converter and target pa-
rameters with taking into account the radiation proper-
ties of the used materials used and the requirements of
the cooling system. The optimization of such a system is
considered in this work.
1. CALCULATION METHOD
Such optimization tasks are the multi-objective op-
timization problems with taking into account the various
physical processes. To carry out appropriate calcula-
tions we developed principles and three-dimensional
models using Monte Carlo methods to calculate the ra-
diation fields, nuclear reactions, and the released energy
in the materials of the system, as well as the methods of
computational fluid dynamics (Computational fluid dy-
namics - CFD) calculations of the cooling conditions
and system thermal-hydraulic parameters [4].
Bremsstrahlung converter is a lead cylinder in the
copper shell with water cooling. The target for produc-
tion of the 99Mo isotope is set of large and small disks
from natural molybdenum sandwiched between copper
plates for efficient air cooling (Fig. 1).
99Mo isotope produced due to the fact that the prima-
ry electron beam generates bremsstrahlung photons in
the lead converter, and if the converter thickness is not
sufficient to absorb electrons − and then also in the mo-
lybdenum. Photon with energies greater than the thresh-
old value of the converter material participate in various
reactions, such 208Pb(γ, n)207Pb, and in the target area − in
the reaction 100Mo(γ, n)99Mo with probabilities which are
proportional to the reaction cross sections. As a result,
both the converter and the target generates photonuclear
neutrons that may also take part in the production of the
desired isotope by reaction 98Mo(n, γ)99Mo.
Calculation of neutron and gamma radiation fields
was carried out by Monte Carlo method using MCNPX
software, with taking into account all the possible nu-
clear reactions that may result in the 99Mo isotope pro-
duction. However, the main contribution to the isotope
production for the considered electron energy comes
from the reactions 100Mo(γ, n)99Mo and 98Mo(n, γ)99Mo.
mailto:khazhm@kipt.kharkov.ua
ISSN 1562-6016. ВАНТ. 2013. №6(88) 215
The irradiation of electrons with 34.7 MeV energy
(beam diameter 10 mm, the current 250 μA) was simu-
lated. The simulation of RZ symmetry RZ is shown at
Fig. 2.
To estimate the efficiency of channels and optimiza-
tion of system for 99Mo isotope production it is neces-
sary to estimate the neutron and gamma leakage from
the system, for this purposes cylindrical surface 1, 2 and
plane 3 was introduced in this model (see Fig. 2,b).
Some simulation results for the neutron fluxes are
shown below. The integrated neutron flux outside the
assembly was 6.54⋅1012 n/s.
Fig. 1. Solid model of the facility for 99Mo production:
а) general view; b) cross-cut
Fig. 2. Simulation scheme for 99Mo production using
the Monte-Carlo method а) general view; б) scheme
with additional cylinder surfaces 1, 2 and plane 3
Fig. 3. Cross-section of 98Mo(n, γ) 99Mo reaction
The neutron flux crossing the surface 1 is equal to
1.646⋅1011n/cm2/s. The neutron flux crossing the surface 2
is 1.258⋅1011n/cm2/s. The neutron flux crossing the surface
3 – 1.264⋅1011n/cm2/s. The neutron yield for a given elec-
tron energy and converter + target geometry is 8.3⋅10-3 n/e-.
The neutron flux in the target is 2.5⋅10-4 n/e-/cm2. In
addition, the cross-section of 98Mo(n, γ)99Mo reaction
has resonances (Fig. 3), therefore, 99Mo is effectively
produced from irradiation with neutrons in the energy
range 10 eV…1 keV. However, since the spectrum cor-
responds to the photo-nuclear neutron spectrum, the
effective cross section of the reaction is less than 1 Barn
(Figs. 3, 4). Hence, the efficiency of the reaction
100Mo(γ, n)99Mo will not high. This assumption is fully
agreed with the simulation results.
In the simulation of this system the following ratio
of 99Mo production was found: 99.66 % as a result of
the 100Mo(γ, n)99Mo reaction and 0.34 % from the
98Mo(n, γ)99Mo reaction.
Fig. 4. Neutron spectrum in the target
2. EFFICIENCY OF THE 98Mo(n, γ)99Mo
CHANNEL
The maximum intensity of the photonuclear neutron
flux is restricted with primary electron energy. The neu-
tron spatial distribution in the RZ symmetry is shown at
Fig. 5. The system can be optimized by adding a moder-
ator and reflector to increase the neutron flux density
and providing in the target area the resonance energy in
the range 1 eV…1 keV.
Fig. 5. Spatial distribution of the neutron fluxes in the
converter-target system
The system can be modified by adding polyethylene
moderator and graphite reflector with thickness 10 cm
or more.
The modeling results showed that it is possible to in-
crease the reaction contribution up to 1%. However,
even if we moderate all leakage photonuclear neutrons
to resonance energies and redirect them back to the tar-
get, the efficiency of 98Mo(n, γ)99Mo reaction will be
less than 50% compared to 100Mo(γ, n)99Mo reaction.
Taking into account the significant neutron loss due
moderating and scattering, the maximum contribution
will not exceed 1…2%.
b а
a b
ISSN 1562-6016. ВАНТ. 2013. №6(88) 216
Taking into account the cooling efficiency reducing
when moderator and reflector are used we can conclude
that for the given primary electron energy costs for in-
creasing the reaction 98Mo(n, γ)99Mo efficiency exceeds
benefit from light increasing the 99Mo isotope produc-
ing.
Therefore, the optimization of the system based on
the 98Mo(n, γ)99Mo channel performance is not feasible.
3. EFFICIENCY OF THE 100Mo(γ, n) 99Mo
CHANNEL
Bremsstrahlung converter is the lead disc of 7 mm
thickness and 26 mm diameter.
Molybdenum target is the assembly of 91 disks of
0.2 mm thickness and 10 mm and 26 mm diameters and
which is sandwiched between copper disks of 2 mm
thick and 30 mm diameter. The energy electron beam
energy is 34.7 MeV, the beam current is 250 μA.
The modeling results showed that:
• energy release in the converter is 4,124.75 Watts.
The water cooling is used to ensure the operation;
• energy release in the molybdenum assembly is 725
watts. Here air cooling is possible.
4. STUDYING OF THE ASSEMBLY
PARAMETERS CONCERNING
THE 99Mo PRODUCING
The efficiency of 99Mo producing is defined by the
gamma flux energy distribution, as 100Mo(γ, n)99Mo
reaction has photon threshold at 8.29 MeV. The photon
distribution in the target for energies above 8 MeV is
shown at Fig. 6.
Fig. 6. Photon flux distribution in the target (91 disk)
From the analysis of the obtained distribution it can
be seen that the flux in the last molybdenum disk is
more than 35 % in the first. Therefore, to increase the
efficiency of isotope producing it is possible to increase
the target volume by increasing the number of disks, or
placing the second target after the primary one for pre-
liminary isotope production. Calculations showed that
after increasing the number of disks from 91 to 127 the
efficiency of 99Mo producing is increased by 18 %. The
photon distribution for 127 discs is shown in Fig. 7.
Fig. 7. Photon distribution in the target (127 disks)
5. STUDYING OF THE CONVERTER
PARAMETERS CONCERNING THE 99Mo
PRODUCING
In our case, 100Mo(γ, n)99Mo is the main channel of
99Mo producing and hence we must ensure the maxi-
mum high-energy photon flux in the target.
Earlier, the modeling results showed that the most
effective thickness of the converter is 4 mm, in which
high-energy photons from converter bremsstrahlung
interact with the assembly (for 7 mm thickness they are
absorbed in the converter) and transmitted electrons
generate additional bremsstrahlung directly to the mo-
lybdenum. For converter of 4 mm thickness efficiency
of 99Mo isotope producing is increased by 24%. Howev-
er, the use of converter with such thickness is difficult
because of problems of target air-cooling. Energy, re-
leased on the target, was 1.687 watts, of which 901.5
watts was due to the electrons.
To reduce the energy released it was proposed to
put an absorber of electrons after the target and to use
the material with atomic number small enough to pre-
vent excessive absorption of high-energy photons.
We modeled converters of different configurations,
such as Pb + Al, Pb + Cu, Pb + Be. As there are re-
strictions due to assembly air cooling optimal converter
is 4 mm Pb + 5 mm Cu.
In this case, the efficiency of 99Mo isotope produc-
ing is 10% higher than for 7 mm converter and energy
released in the target was ≈771 W, that corresponds to
the value of the released energy for 7 mm converter.
6. MODELING OF THE COOLING
CONDITIONS AND STUDYING
THE TEMPERATURE GRADIENTS
OF THE SYSTEM
An important problem in the design of this class is
the choice of optimal cooling conditions and related
thermo-mechanical parameters that provide secure
mode and a long life of the designed system.
The study of temperature gradients during irradia-
tion and cooling is an important task, since the presence
of significant temperature gradients can lead to thermo-
mechanical stress and performance degradation of the
target, right up to the destruction of the structure. Dur-
ISSN 1562-6016. ВАНТ. 2013. №6(88) 217
ing irradiation temperature gradients occur not only
because of the unevenness in the energy release, but
also due to uneven cooling of the target, caused by the
geometrical characteristics of cooling system.
Modeling of radiation using Monte Carlo method
provides information about the energy released in irra-
diated object of research and using the data for thermal-
hydraulic parameters of the system.
To calculate the thermal-hydraulic parameters and
cooling conditions the three-dimensional solid model of
the optimized system was developed. The heat source is
modeled on the basis of data on the energy release ob-
tained by the Monte Carlo simulation (Fig. 8).
Calculation was done for molybdenum assembly
consisting from 91 disks as the most energy-intensive
event.
Fig. 8. Solid model of the optimized converter for
calculation the target thermal-hydraulic parameters
and cooling conditions
The thermohydraulic parameters and cooling condi-
tions system can be calculated by solving the thermody-
namics and hydrodynamics adjoint problem. In the
three-dimensional geometry of the most accurate solu-
tion can be obtained by using computational fluid dy-
namics (CFD) method and the finite volume method.
The modeling was done using the SolidWorks Flow
Simulation software package [5, 6].
SolidWorks − a versatile tool for analysis in hydrau-
lic gas dynamics and heat transfer. SolidWorks Flow
Simulation is hydraulic gas dynamics analysis module
in the SolidWorks.
The input parameters can be: velocity, pressure,
mass and volume flow of liquid or gas. Heat sources
may be volume and surface. In our case we consider
anisotropic volume sources.
In the software package SolidWorks Flow Simulation
motion and heat transfer of the flow medium is modeled
by the Navier-Stokes equations, which give the laws of
conservation of mass, momentum and energy in the non-
stationary problems. In addition, the equation of state of
environment components, and the empirical dependences
of the viscosity and thermal conductivity of these compo-
nents on the temperature are used. Non-Newtonian fluids
are set as the dependence of the viscosity on the rate of
shear deformation and temperature; compressible fluids
are given as density dependence on the pressure. These
equations simulate turbulent, laminar and transitional
flows. The transition between laminar and turbulent flow
is determined by the critical value of the Reynolds num-
ber. For simulation of turbulent flows, the Navier-Stokes
equation are averaged by Reynolds, i.e. we use the aver-
age for small time interval the turbulence influence on
the flow parameters (pressure, speed, temperature),
which take into account for by applying appropriate
time derivatives. As a result, the equations have addi-
tional terms of the Reynolds stress and to close this sys-
tem of equations SolidWorks Flow Simulation uses the
transport equation of turbulent kinetic energy and its
dissipation within a -ε turbulence model.
The system of equations of conservation of mass,
momentum and energy of non-stationary spatial flow
looks like the approach of Euler in the Cartesian coordi-
nate system (xi, i = 1, 2, 3), rotated with angular veloci-
ty Ω about an axis passing through its beginning:
( ) ;0=
∂
∂
+
∂
∂
k
k
u
xt
ρρ
( ) ( ) ;i
i
kki
k
i S
x
Puuu
xt
u
=
∂
∂
+−
∂
∂
+
∂
∂ τρρ
( )( ) ( )( ) Hkkiikkk
k
QuSuquPE
xt
E
+=−++
∂
∂
+
∂
∂ τρρ ,
where t – time; u – velocity of the flow medium; ρ –
density of the flow medium; P – pressure of the flow
medium; Si – external mass forces, acting on the mass
unit of the flow medium (Sporous bodies – effect of re-
sistance of the porous body, Sgravitation – effect of gravita-
tion, Srotation – effect of coordinate system, rotation, i.e.
Si = Sporous bodies + Sgravitation + Srotation); E – full energy of
mass unit; QH – heat from the heat source per unit vol-
ume of the flowing medium; τ – tensor of viscous shear
stress; qi – diffusive heat flux. Lower indices indicate
summation over the three coordinate directions.
As used differential and integral equations have no
analytical solutions, they are reduced to a discrete form
and solved on a computational grid (can be digitized in
space or in time).
When digitizing in space:
• estimated area is covered by the computational
grid, the edges of cells of which are parallel to the coor-
dinate planes;
• values of the independent variables are calculated
at the centers of the cells (finite volume method);
• computational grid cells have the shape of the box;
• the area in which this net is constructed has a par-
allelepiped shape;
• on the border with the solid body, the procedures
of local cell-division are used.
When digitizing in time:
• For each cell of the computational grid the maxi-
mum allowable time step is determined;
• step depends on the physical values and the sam-
pling step in space in the cell.
Three separate classes of finite volume mesh are
used for solving problems of heat transfer.
1. Creating the computation area and generation of
the grid in the flow area for calculating the diffusion
flow in liquid or gas
,
x
Tc
P
q
k
p
c
t
r
l
k ∂
∂
+−=
σ
µµ
where Pr – Prandtl number; cp – specific heat at con-
stant pressure; μl – coefficient of dynamic viscosity, μt
– coefficient of turbulent viscosity.
ISSN 1562-6016. ВАНТ. 2013. №6(88) 218
2. Creating the computation area and generation of
the grid in the solid body area for calculating the heat
transfer
,Q
x
T
xt
pe
H
ii
+
∂
∂
∂
∂
=
∂
∂ λ
where e = cT (c – specific heat; T – temperature); λ –
thermal conductivity; QH – heat from the heat source
per unit volume.
3. Creating the computation area and generation of
the grid in the bound of flow area solid area. Convective
heat transfer between the solid surface and the fluid is
modeled in the modeling of the boundary layer fluid
flow.
An important advantage of used system is the possi-
bility to generate a computational grid directly on the
SolidWorks model, the creation of the computational
area and mesh generation in the solid and the flow re-
gion.
After generation of the computational area and com-
puting grid it is necessary to determine the volume heat
sources. To take into account the anisotropy of the heat
distribution in the converter lead and copper discs were
uniformly divided into regions in RZ symmetry with
dimensions 10×10 for lead and copper disc respectively.
For each of the 200 areas, using the results of radiation
calculations by Monte Carlo method, it was defined the
appropriate heat source, volume-averaged in the corre-
sponding area. The simulation results are shown below.
Water flow and temperature distribution in the
bremsstrahlung converter and cross-section at the plane
of maximum temperature of the lead disk are shown at
Figs. 9 and 10, respectively.
Fig. 9. Water flow paths with the temperature
distribution in the converter cooling system
Analysis of the temperature distribution for the tar-
get shows that, while air cooling (flow rate 15 m/s) dur-
ing irradiation the target is substantially heated and the
maximum temperature in the first disks reaches values
of more than 700 °C. Therefore, in the model calcula-
tions we take into account additional heat loss by radia-
tion surfaces. The temperature distribution in the cross-
cut corresponding to the maximum temperature in the
assembly of molybdenum disks is shown in Fig. 11 (red
and blue points in the figure correspond to the maxi-
mum and minimum temperatures).
Fig. 10. Temperature distribution in the converter.
Cross-cut in the region of temperature maximum
Fig. 11. Temperature distribution in the converter.
Cross-cut in the region of temperature maximum
in the molybdenum disks
The temperature gradient between the hottest and
coldest molybdenum discs is 300 °C. The temperature
gradient in the bremsstrahlung converter reaches about
200 °C (maximum temperature of the lead disc corre-
sponds to turbulence zone in the cooling system liquid).
When operating similar systems it is necessary to take
into account the temperature gradients, so the relevance
of this calculation method is not in doubt.
CONCLUSIONS
To simulate radiation and thermal-hydraulic charac-
teristics of the system for 99mTc isotope production spe-
cial procedure was developed, using the Monte Carlo
method and computational fluid dynamics for modeling
of thermal-hydraulic characteristics. To simulate and
optimize the converter – target system three-
dimensional solid models of the system were developed,
which completely describe the geometry of the system
and take into account all the necessary initial conditions.
The simulation of the system was done in order to
improve the efficiency of obtaining the 99mTc isotope.
It is shown that for specified electron energy it is not
appropriate to use additional reflectors and moderators
to increase the 98Mo(n, γ)99Mo reaction efficiency.
Analysis of the obtained data showed that to in-
crease the efficiency of 99mTc producing it is necessary:
ISSN 1562-6016. ВАНТ. 2013. №6(88) 219
• to replacement the 7 mm lead converter with com-
bined converter ( 4 mm lead + 5 mm copper);
• to increase the target thickness by increasing the
number of molybdenum plates.
To ensure the system operation it is necessary to
provide the water cooling of the converter with water
volume flow of 2 l/s and the air cooling of the target
with air flow of 15 m/s.
The modeling results show the presence of high
temperature gradients, which can cause large thermo-
mechanical stresses.
The method developed by us have to be used to min-
imize the potential risks of system functioning, with
taking into account the technical parameter of the
equipment used in the cooling system to change the
values of water volumetric flow and air flow rate as well
as the modification of the geometrical parameters of the
system to minimize temperature gradients in the process
of the complex operation.
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Article received 09.10.2013
МОДЕЛИРОВАНИЕ РАДИАЦИОННЫХ И ТЕРМОГИДРАВЛИЧЕСКИХ ХАРАКТЕРИСТИК
СИСТЕМЫ КОНВЕРТЕР-МИШЕНЬ ПРИ ОБЛУЧЕНИИ ЕЕ ЭЛЕКТРОНАМИ
ДЛЯ ОПТИМИЗАЦИИ НАРАБОТКИ ИЗОТОПА 99mTc
Е.В. Рудычев, С.И. Прохорец, Д.В. Федорченко, М.А. Хажмурадов
Разработана методика расчетов моделирования радиационных и термогидравлических характеристик си-
стемы получения изотопа 99mTc, использующая метод Монте-Карло для радиационных полей системы и ме-
тод вычислительной гидродинамики для термогидравлических характеристик системы. Созданы трехмер-
ные твердотельные модели системы, полностью описывающие геометрию системы и учитывающие необхо-
димые начальные условия. Рассмотрена наработка изотопа 99Mo за счет (γ, n)- и (n, γ)-реакций и проведен
анализ их эффективности. Для повышения эффективности наработки изотопа 99Mo и уменьшения энерговы-
деления в материале мишени предложено использовать композитный конвертер типа Pb+Al, Pb+Cu, Pb+Be,
для которого определены оптимальные параметры. Применение методики дает возможность оптимизиро-
вать эксплуатационные характеристики системы получения изотопа 99mTc.
МОДЕЛЮВАННЯ РАДІАЦІЙНИХ ТА ТЕРМОГІДРАВЛІЧНИХ ХАРАКТЕРИСТИК СИСТЕМИ
КОНВЕРТЕР-МІШЕНЬ ПРИ ОПРОМІНЕННІ ЇЇ ЕЛЕКТРОНАМИ ДЛЯ ОПТИМІЗАЦІЇ
НАПРАЦЮВАННЯ ІЗОТОПУ 99mTc
Є.В. Рудичев, С.І. Прохорець, Д.В. Федорченко, М.А. Хажмурадов
Розроблено методику розрахунків моделювання радіаційних та термогідравлічних характеристик систе-
ми отримання ізотопу 99mTc, яка використовує метод Монте-Карло для радіаційних полів системи і метод
обчислювальної гідродинаміки для термогідравлічних характеристик системи. Створено тривимірні твердо-
тільні моделі системи, які повністю описують геометрію системи та враховують необхідні початкові умови.
Розглянуто напрацювання ізотопу 99Mo за рахунок (γ, n)- і (n, γ)-реакцій та проведено аналіз їх ефективності.
Для підвищення ефективності напрацювання ізотопу 99Mo та зменшення енерговиділення в матеріалі мішені
запропоновано використовувати композитний конвертер типу Pb+Al, Pb+Cu, Pb+Be, для якого визначено
оптимальні параметри. Застосування методики дає можливість оптимізувати експлуатаційні характеристики
системи отримання ізотопу 99mTc.
http://www.solidworks.com/sw/products/simulation/flow-simulation.htm
http://www.solidworks.com/sw/products/simulation/flow-simulation.htm
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| id | nasplib_isofts_kiev_ua-123456789-112092 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 1562-6016 |
| language | English |
| last_indexed | 2025-12-07T18:49:50Z |
| publishDate | 2013 |
| publisher | Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| record_format | dspace |
| spelling | Rudychev, Ye.V. Prokhorets, S.I. Fedorchenko, D.V. Khazhmuradov, M.A. 2017-01-17T15:34:31Z 2017-01-17T15:34:31Z 2013 Modeling of radiation and thermal-hydraulic characteristics of the converter-target under irradiation with electrons in order to optimize isotope ⁹⁹mTc production / Ye.V. Rudychev, S.I. Prokhorets, D.V. Fedorchenko, M.A. Khazhmuradov // Вопросы атомной науки и техники. — 2013. — № 6. — С. 214-219. — Бібліогр.: 6 назв. — англ. 1562-6016 PACS: 24.10Lx, 29.25Rm, 61.80.Ed, 87.53Wz, 87.58Ji https://nasplib.isofts.kiev.ua/handle/123456789/112092 The method of the modeling of radiation and thermal-hydraulic characteristics of the system for ⁹⁹mTc isotope production was developed, using the Monte Carlo method for computation of radiation fields and computational fluid dynamics for modeling of thermal-hydraulic characteristics. The three-dimensional solid models of this system were developed, where system geometry was fully described and necessary initial conditions was taking into account. We considered the isotope ⁹⁹Mo production due to the (γ, n) and (n, γ) reactions and analyzed the efficiency of these reactions. To improve the efficiency of the isotope ⁹⁹Mo production and to reduce the energy deposition in the target material it is proposed to use the composite converter made of Pb + Al, Pb + Cu, Pb + Be, for which the optimal parameters were defined. Application of this method makes it possible to optimize the performance of the system for ⁹⁹mTc isotope production. Розроблено методику розрахунків моделювання радіаційних та термогідравлічних характеристик системи отримання ізотопу ⁹⁹mTc, яка використовує метод Монте-Карло для радіаційних полів системи і метод обчислювальної гідродинаміки для термогідравлічних характеристик системи. Створено тривимірні твердотільні моделі системи, які повністю описують геометрію системи та враховують необхідні початкові умови. Розглянуто напрацювання ізотопу ⁹⁹Mo за рахунок (γ, n)- і (n, γ)-реакцій та проведено аналіз їх ефективності. Для підвищення ефективності напрацювання ізотопу ⁹⁹Mo та зменшення енерговиділення в матеріалі мішені запропоновано використовувати композитний конвертер типу Pb+Al, Pb+Cu, Pb+Be, для якого визначено оптимальні параметри. Застосування методики дає можливість оптимізувати експлуатаційні характеристики системи отримання ізотопу ⁹⁹mTc. Разработана методика расчетов моделирования радиационных и термогидравлических характеристик системы получения изотопа ⁹⁹mTc, использующая метод Монте-Карло для радиационных полей системы и метод вычислительной гидродинамики для термогидравлических характеристик системы. Созданы трехмерные твердотельные модели системы, полностью описывающие геометрию системы и учитывающие необходимые начальные условия. Рассмотрена наработка изотопа ⁹⁹Mo за счет (γ, n)- и (n, γ)-реакций и проведен анализ их эффективности. Для повышения эффективности наработки изотопа ⁹⁹Mo и уменьшения энерговыделения в материале мишени предложено использовать композитный конвертер типа Pb+Al, Pb+Cu, Pb+Be, для которого определены оптимальные параметры. Применение методики дает возможность оптимизировать эксплуатационные характеристики системы получения изотопа ⁹⁹mTc. en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Вопросы атомной науки и техники Применение ускоренных пучков. Детекторы и детектирование ядерных излучений Modeling of radiation and thermal-hydraulic characteristics of the converter-target under irradiation with electrons in order to optimize isotope ⁹⁹mTc production Моделювання радіаційних та термогідравлічних характеристик системи конвертер-мішень при опроміненні її електронами для оптимізації напрацювання ізотопу ⁹⁹mTc Моделирование радиационных и термогидравлических характеристик системы конвертер-мишень при облучении ее электронами для оптимизации наработки изотопа⁹⁹mTc Article published earlier |
| spellingShingle | Modeling of radiation and thermal-hydraulic characteristics of the converter-target under irradiation with electrons in order to optimize isotope ⁹⁹mTc production Rudychev, Ye.V. Prokhorets, S.I. Fedorchenko, D.V. Khazhmuradov, M.A. Применение ускоренных пучков. Детекторы и детектирование ядерных излучений |
| title | Modeling of radiation and thermal-hydraulic characteristics of the converter-target under irradiation with electrons in order to optimize isotope ⁹⁹mTc production |
| title_alt | Моделювання радіаційних та термогідравлічних характеристик системи конвертер-мішень при опроміненні її електронами для оптимізації напрацювання ізотопу ⁹⁹mTc Моделирование радиационных и термогидравлических характеристик системы конвертер-мишень при облучении ее электронами для оптимизации наработки изотопа⁹⁹mTc |
| title_full | Modeling of radiation and thermal-hydraulic characteristics of the converter-target under irradiation with electrons in order to optimize isotope ⁹⁹mTc production |
| title_fullStr | Modeling of radiation and thermal-hydraulic characteristics of the converter-target under irradiation with electrons in order to optimize isotope ⁹⁹mTc production |
| title_full_unstemmed | Modeling of radiation and thermal-hydraulic characteristics of the converter-target under irradiation with electrons in order to optimize isotope ⁹⁹mTc production |
| title_short | Modeling of radiation and thermal-hydraulic characteristics of the converter-target under irradiation with electrons in order to optimize isotope ⁹⁹mTc production |
| title_sort | modeling of radiation and thermal-hydraulic characteristics of the converter-target under irradiation with electrons in order to optimize isotope ⁹⁹mtc production |
| topic | Применение ускоренных пучков. Детекторы и детектирование ядерных излучений |
| topic_facet | Применение ускоренных пучков. Детекторы и детектирование ядерных излучений |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/112092 |
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