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NGS-Concrete - New Generation Shielding Concrete against Ionizing Radiation - the Potential Evaluation and Preliminary Investigation

100%
Piotrowski T., Tefelski D., Sokołowska J., Jaworska B.
Acta Physica Polonica A
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2015
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vol. 128
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issue 2B
B-9-B-13
EN
Concrete is a common material used as a shielding against ionizing radiation due to the relatively low cost and the ability to meet the structural function. State of the art in concrete shielding is that while in case of gamma radiation an increase in density by a change of aggregate is usually efficient enough, protection against neutrons is more complex. It is due to the differences in interactions of neutrons with the matter, depending on their kinetic energy and reaction cross-sections with the component atoms of the cement paste and the aggregate. Last progress in concrete evolution due to use of polymer additives (e.g. superplasticizers) together with reactive additions (e.g. silica fume) allows for a new look at the concrete design for radiation shielding purposes. One of the main advantages of concrete is its composite-type and there is a potential for the optimization of its constituents as well as mixture proportions. The paper presents the preliminary results of the project NGS-Concrete - new-generation shielding concrete against ionizing radiation. The aim of the project is to design the composition of concrete against ionizing radiation, achieved by the use of experiment based multi-criteria optimization of materials supported by the Monte Carlo simulations. The purpose of presented studies was to evaluate neutron shielding properties of ordinary and heavy-weight magnetite concrete modified with epoxy resin and gadolinium oxide. At first the shielding efficiency against neutrons from LWR neutron flux source and Pu-Be was simulated in MCNP code. At the end the comparison of MCNP simulated results and real experiment was presented. It was proved that both methods of modification can improve neutron shielding properties concrete but gadolinium oxide is an efficient additive only for low energy neutron attenuation.
2
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Experiments on Neutron Transport through Concrete Member and the Potential for the Use in Material Investigation

100%
Piotrowski T., Tefelski D., Skubalski J., Żak A.
Acta Physica Polonica A
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2015
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vol. 128
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issue 2B
B-14-B-18
EN
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.
3
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Project of the Underwater System for Chemical Threat Detection

80%
Silarski M., Hunik D., Moskal P., Smolis M., Tadeja S.
Acta Physica Polonica A
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2015
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vol. 127
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issue 5
1543-1547
EN
In this article we describe a novel method for the detection of explosives and other hazardous substances in the marine environment using neutron activation. Unlike the other considered methods based on this technique we propose to use guides for neutron and gamma quanta which speeds up and simplifies identification. Moreover, it may provide a determination of the density distribution of a dangerous substance. First preliminary results of Monte Carlo simulations dedicated for design of a device exploiting this method are also presented.
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