Experiments on Neutron Transport through Concrete Member and the Potential for the Use in Material Investigation
T. Piotrowskia, D.B. Tefelski b, J. Skubalski c and A. Żak d
aWarsaw University of Technology, Faculty of Civil Engineering, Warsaw, Poland
bWarsaw University of Technology, Faculty of Physics, Warsaw, Poland
cMedical University, Department of Synthesis and Technology of Drugs, Łódź, Poland
dUniversity of Łódź, Faculty of Physics and Applied Informatics, Łódź, Poland
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Concrete has been used as a shield against high-energy photons and neutrons since the beginning of use of nuclear reaction in energy, medicine and research. From that time the progress in concrete technology is huge - very good concrete used in 60's was about 30 MPa compressive strength, and now the recommendation of ETC-C is to use in EPR nuclear power plant the concrete at least class C45/55 for airplane resistant shell or class C40/50 for other structures. The Monte Carlo computer simulations indicate that an increase in density of the shielding member has a minor effect on the weakening of neutron transport and, therefore, the optimal composition of a shielding concrete against gamma radiation is different than the optimal composition of shielding concrete against neutron radiation. Neutron stopping is a two-step effect: slowing down of fast neutrons and absorption of thermal ones. Both result from the atomic composition of the barrier. The paper presents an analysis of neutrons transport through concrete cement mortar and polymer cement composites mortar based on specially designed experiments which allows for measuring fast neutron attenuation and thermal neutron capture separately. The aim of experiments was to find an influence of the cement type, polymer addition and moisture content on both aspects of neutron shielding properties of a composite. The experimental results were confirmed in MCNP simulations. There was found an influence of cement type on fast neutron attenuation due to differences in chemical composition. Next an important improvement of both fast neutron attenuation and thermal neutron capture due to polymer modification of concrete. The last was fond of clear linear relationship between fast neutron attenuation to the hydrogen content which shows the possibility of using this phenomenon in building material investigation like measurement of moisture content or polymer content in the polymer cement composites.

DOI: 10.12693/APhysPolA.128.B-14
PACS numbers: 28.20.Fc, 28.41.Qb