The shielding of neutrons produced in applications with high energy radiation is of great importance in terms of the radiation safety of the working personnel and the ability to operate for a long time without losing the functions of the surrounding electronic devices. For this purpose, the doors and walls of the radiation zone must be armored.
Depending on the type of radiation generated, different materials are used for shielding. Lead is used for gamma radiation and hydrogen and boron containing materials are used for neutron radiation. Shielding products used in our country for protection against neutron radiation in areas such as health and energy applications are supplied from abroad. In this project, neutron shielding material will be produced by developing composite samples made of boron compounds and others. The project will be realized in partnership with KTÜ, METU and MODEDOOR. Within the scope of this project, new boron containing shielding material will be developed by MODEDOOR. The main objectives of the project are the design and production of boron and polyethylene containing shielding materials and the radiation permeability tests of these armor materials. Although there are many scientific studies conducted in our country with the aim of shielding the neutrons that emerge as secondary particles in some applications with radiation, the number of commercialized products at the level accepted by international companies is almost nonexistent.
In this project, it is aimed to develop and produce neutron shielding material that can absorb high and low energy neutrons from MODEDOOR company. The project will be realized in partnership with Karadeniz Technical University, Middle East Technical University and MODEDOOR. Unlike the boron-containing armoring shield produced by MODEDOOR for neutron radiation, the design, production and radiation absorption and mechanical testing of these armor materials are the main objectives of the project. The interactions of composite armor materials produced
with neutrons of different energies will be simulated using software such as Fluka and Geant4, and then these simulated materials will be experimentally produced, and tested under the wide energy range (0.1 eV-20 MeV) of the METU Scattering Beam Line (METU-SDH). Various rays, such as x-rays, gamma rays or neutron rays, are used in various applications, such as nuclear reactors, diagnostic medicine and safety engineering.
With the proposed project, innovative neutron shielding materials will be produced for MODEDOOR
company. This neutron shielding material will be layered with shielding properties for high and low energy
neutrons. Since boron derivatives will be used in the production of neutron shielding material, a new
usage area will be provided for boron products produced in our country. Software such as Fluka and
Geant4 will determine the material content (content, additive ratio, thickness etc.) by simulation
technique. Later, using simulation technique results, polyethylene composite material with boron and
…… additive layer will be produced in KTÜ by extrusion method. The neutron permeability of the armor
materials produced will be tested experimentally in METU-SDH with neutrons produced in a wide range
of energy and a suitable Am-Be source. In addition, XRD, SEM, thermal (DSC, TGA, MFI, Vicat / HDT test)
and mechanical (tensile, bending, hardness, impact) tests of composite materials will be carried out at
KTÜ.
1)Simulation calculations: At this stage, the parameters (thickness, ratio, additive, etc.) of the armor material to be produced using software such as Fluka and Geant 4 will be determined. Using simulation technique, experimental conditions will be modeled and animated in computer environment. As a result of simulation calculations, the boron, bismuth oxide ratios to be used in composite material and the thickness of each layer and the total material thickness will be determined. This phase of the project covers concept development and technical feasibility and design activities.
2) Production and mechanical tests of composite material: At this stage, a layer of neutron shielding composite material will be produced by adding boron and bismuth oxide (or different chemicals deemed appropriate as a result of simulation) into the matrix. In addition, the mechanical, structural, thermal and morphological properties of the materials produced will be determined. This part of the project includes laboratory studies and prototype production activities that take place in the transition from concept to design.
3)Experimental determination of neutron and gamma absorption rates of composite material: Neutron absorption rates of composite material manufactured will be tested with neutrons produced by METU-SDH and experiments will be repeated with Am-Be source. Mass absorption coefficients for gamma will be determined for Cs-137, Co-60 and Ba-133. This stage of the project includes the activities of design implementation and verification.
4)Comparison of the test and simulation results: The data obtained from the test results will be compared with the simulation results and if the materials compatible with the simulation results are not produced, the test conditions in the material production will be reviewed and optimized and the tests will be repeated. The R&D phase tha twill take place in this part of the project covers design verification studies and solution of design problems.
Neutron and gamma absorption measurements of the material to be produced will be tested using two different experimental setups.
a) Neutron absorption experiment using neutrons produced by METU-SDH:
The products produced will be experimented on and the shielding properties will be determined both by
simulation technique and experimentally. At this stage, the most important challenge faced by neutron
researchers is the supply of neutrons. METU-SDH is also a source of neutrons because of the neutrons
produced as a result of the interaction of protons with the material which enables neutron radiation
experimental studies. In this project, METU-SDH supplying different energy neutrons will be used as a
neutron source and will be used to determine the neutron shielding properties of the produced materials.
b) Absorption test using Am-Be source:
Neutron absorption analysis of 19 mm diameter samples prepared in accordance with the experimental
geometry will be carried out with the neutron measurement system with the Am-Be neutron source and
BF3 neutron detector in TAEK-SANAEM. Some features of the experimental setup to be used are given in
Table 1 (see APPENDICES).
c) Gamma Absorption Coefficient Measurement:
Ortec brand HPGe gamma spectrometer and point gamma sources (Cs-137, Ba-133, Co-60) in the
Research Laboratory of the Karadeniz Technical University Physics Department will be used in the
measurement of gamma absorption coefficients. Background counts will be made in absorption geometry
using point sources first. The samples will then be placed between the source and the detector, and
measurements will be repeated for each sample. The planned number of counts for each measurement
is 5000 s. By taking the background measurements from the measurements made, the calculation of the
gamma ray mass absorption coefficient will be made based on the calculation of the area for each energy
peak.
d) Comparison of experimental results and simulation results:
The method to be used in the development of neutron shielding materials is a comprehensive study of
using advanced software calculating with the Monte Carlo Method, simulations carried out in the
computer environment and finally, the material content and design optimized by simulations
experimental testing. The advantages of the project team are that they can use advanced software that
can simulate applications involving radiation in a computer environment and can perform experimental
studies by using the wide range of neutrons produced by sources such as METU-SDH. The shielding
properties will be determined both by simulation and experimental techniques.
– TAEK shielding calculations guides
– TAEK Guideline on Preparing Radiation Protection Program in Medical Radiology Applications (RSGDKLV-14)
– TAEK – Guideline on Radiation Protection Equipment (RSGD-KLV-020)
– TAEK -Guideline for Radiation Protection Program in Nuclear Medicine Applications (RSGD-KLV-030)
– TAEK – Radiation Protection Guideline for Consumer Products Containing Radioactive Material (RSGDKLV-029)
– ASTM D638 Standard Test Method for Tensile Properties of Plastics
– ASTM D790, Standard Test Methods for Flexural Properties of Unreinforced and Reinforced Plastics and
Electrical Insulating Materials
– ASTM D256 Standard Test Methods for Determining the Izod Pendulum Impact Resistance of Plastics
– ASTM D2240 Standard Test Method for Rubber Property – Durometer Hardness
– ASTM D1505 Standard Test Method for Density of Plastics by the Density-Gradient Technique
Simulation work:
-Abdulrahman ALBARODİ: He is a graduate of METU Chemical Engineering and Physics
Department and a graduate student at METU physics department. Shielding calculations with Geant-4
simulation program.
– Pelin Uslu: She is a graduate of METU Physics Department and METU-Materials Metallurgy
Department. Shielding calculations with Fluka simulation program.
Production of the prototype product:
– Ümit Alver: Production of composite materials, the design of which is decided by the simulation
results.
– Fatih Özkalaycı: Production of composite materials whose design was decided by the simulation
program. Prototype Product’s radiation tests:
– Selcen Uzun Duran: Project management and coordination, gamma absorption experiments of
the produced materials.
– Bilge Demirköz: The neutron absorption experiment of the produced materials is carried out
using METU-SDH. Comparing simulation results and experiment results.
– Scholarship Student: Setting up, developing and analyzing the neutron absorption test of the
produced materials using METU-SDH.
Mechanical testing of the prototype product:
– Ümit Alver: Mechanical testing of the composite materials produced.
– Fatih Özkalaycı: Mechanical testing of composite materials produced
