May 9, 2007 - Electrons and Deuterons for Driving Subcritical Assemblies ... Comparative analysis of these two options is presented and discussed.
Comparative Analysis of Neutron Sources Produced by Low-Energy Electrons and Deuterons for Driving Subcritical Assemblies
D. Naberezhnev, Y. Gohar, H. Belch, J. Duo Argonne National Laboratory, Department of Energy, USA
Igor Bolshinsky Idaho National Laboratory, Department of Energy, USA
Fifth International Workshop on the Utilization and Reliability of High Power Proton Accelerators Mol, Belgium May 6-9, 2007
Comparative Analysis of Neutron Sources Produced by Low-Energy Electrons and Deuterons for Driving Subcritical Assemblies Introduction A conceptual design of an accelerator driven subcritical assembly has been developed using the existing accelerators at Kharkov Institute of Physics and Technology (KIPT) in Ukraine. Two different external neutron source options were examined for driving the subcritical assembly. Electrons with energies below 200 MeV and deuterons with energies below 100 MeV were considered. Comparative analysis of these two options is presented and discussed.
Ukraine Accelerator Driven Subcritical Assembly Facility Mission Produce medical isotopes and provide neutron source for performing neutron therapy procedures. Provide capabilities for carrying basic and applied research utilizing the radial neutron beam ports around the subcritical assembly. Support the Ukraine nuclear power industry by providing the capabilities to perform reactor physics experiments and to train young specialists.
Facility Conceptual Design Overview
Vertical Cross Section Through the Facility
View Inside the Subcritical Assembly Showing Overall Arrangement
Comparative Analysis of Neutron Sources Produced by Low-Energy Electrons and Deuterons for Driving Subcritical Assemblies Study Objective: Maximize the neutron production from the available beam power and define the optimal beam parameters.
Study Parameters: Neutron source strength Neutron spatial and energy distributions Energy deposition in the target material Beam radius relative to the target radius Target geometrical configurations Thermal hydraulics results Thermal stress results Target Fabrication
Neutron Yields from Electron Interactions
W 0.10
Neutrons per second
Neutrons per electron
0.15
U
0.05
0.00 50
100 150 Electron energy, MeV
200
Neutron yield per electron from uranium and tungsten targets as a function of the electron energy
5.0 10
14
4.0 10
14
W U 3.0 10
14
2.0 10
14
1.0 10
14
50
100
150
200
Electron energy, MeV
Neutron source strength from tungsten and uranium targets as a function of the electron energy for 100 kW beam power
Neutron Spectrum from Electron Interactions 0.25
0.24 100 MeV 200 MeV
0.2
0.16
Neutron Fraction
Neutron Fraction
0.2
0.12
100 MeV 200 MeV
0.15
0.1
0.08
0.05
0.04
0
0
0.01
0.1
1
10
100
0.01
0.1
Energy, MeV
Neutron spectrum from tungsten target material for different electron beam energies
1
10
100
Energy, MeV
Neutron spectrum from uranium target material for different electron beam energies
Neutron Yields from Deuteron Interactions 0.4
2.5 10
15
2 10
15
1.5 10
15
1 10
15
5 10
14
0.35
Neutron intensity, n/s
Neutrons per deuteron
0.3
0.25
0.2
0.15
0.1
0.05
0
0 0
20
40 60 80 Deuteron energy, MeV
100
120
Neutron yields from deuteron interactions with beryllium as a function of the deuteron energy
0
20
40
60
80
100
120
Deuteron energy, MeV
Neutron source intensity from deuteron interactions with beryllium as a function of the deuteron beam energy normalized for 100 KW beam power
Neutron Spectra Generated from Deuteron-Beryllium Interactions for Different Deuteron Energies 0.2
Neutron fraction
0.15 20 MeV 50 MeV 100 MeV 0.1
0.05
0 0.01
0.1
1 Neutron energy, MeV
10
100
Spatial Energy Deposition in the Tungsten Target Material 120
2000
100
80
50 MeV 100 MeV 150 MeV 200 MeV
Heating rate, W/cm
3
50 MeV 100 MeV 150 MeV 200 MeV
60
3
MeV/cm per electron
1500
1000
40 500
20
0
0
0
2
4
6
8
10
0
2
4
6
8
10
Target Length, cm Target length, cm
Spatial energy deposition per electron in the tungsten target material for different electron energies
Spatial energy deposition in the tungsten target material normalized to 2 KW/cm2 on the beam window for different electron energies
Spatial Energy Deposition in the Uranium Target Material 120
2500
100
3
Heating rate, W/cm
80
60
3
MeV/cm per electron
1875 50 MeV 100 MeV 150 MeV 200 MeV
40
50 MeV 100 MeV 150 MeV 200 MeV
1250
625 20
0 0
2
4
6
8
10
Target length, cm
Spatial energy deposition per electron in uranium target material for different electron energies
0 0
2
4
6
8
10
Target length, cm
Spatial energy deposition in uranium target material normalized to 2 KW/cm2 on the beam window for different electron energies
0.0706
0.1430
0.0705
0.1425
0.0704
0.1420 Neutron per electron
Neutron per electron
Neutron Yields as a Function of the Target Length
0.0703 0.0702 0.0701
0.1415 0.1410 0.1405
0.0700
0.1400
0.0699
0.1395 0.1390
0.0698 5
6
7
8
9
10
Target Length, cm
Number of neutrons per electron from pure tungsten material as a function of the target length for the 200 MeV electron energy
5
6
7
8
9
10
Target Length, cm
Number of neutrons per electron from pure uranium material as a function of the target length for the 200 MeV electron energy
Spatial Energy Deposition in the Beryllium Target Material 300
3 10
4
250
2.5 10
4
2 10
4
1.5 10
4
100
1 10
4
50
5000
heating rate, W/cm
3
200
150
3
MeV/cm per deuteron
20 MeV 50 MeV 100 MeV
20 MeV 50 MeV 100 MeV
0
0 0
0.5
1
1.5
2
2.5
3
3.5
Target length, cm
Spatial energy deposition per deuteron in pure beryllium target material for different deuteron energies
0
0.5
1
1.5
2
2.5
3
3.5
Target length, cm
Spatial energy deposition in pure beryllium target material for different deuteron energies normalized to 2 KW/cm2 on the beam window
Neutron Yields as a Function of the Target Length 0.018 0.4
0.016 0.35
0.3 Neutrons per deuteron
Neutrons per deuteron
0.014
0.012
0.01
0.008
0.25
0.2
0.15
0.006
0.1
0.004 0
2
4
6 8 Target length, cm
10
12
Neutron yield as a function of pure beryllium target length from 23 MeV deuteron
0.05 0
2
4
6 8 Target length, cm
10
12
Neutron yield as a function of pure beryllium target length from 100 MeV deuteron
Comparison of different options for producing neutron source
Exploded Assembly View of the Updated Uranium Target Design
Spatial Energy Deposition Distribution in the Uranium Target Disks
W/cm3
Temperature Distribution in the Uranium Target Disks
Temperature, °C
Third Disk Midplane Temperature Distribution (The Highest Disk Temperature)
Temperature, °C
Third Disk Thermal Stress (The Disk with Highest Thermal Stress)
Conclusions The Comparative analysis of neutron sources produced by lowenergy electrons and deuterons show that: An electron accelerator with electron energy in the range of 150 to 200
MeV is preferred for producing neutron source. The uranium target material produces the highest neutron yield per
electron. The uranium target with 100 KW electron beam produces 3.3x1014 n/s. The thermal hydraulics analyses of the uranium target operating with the
100 KW electron requirements.
beam
power
satisfy
the
engineering
design
The peak thermal stresses (secondary stress) is less than the yield
strength of the uranium target material.
