Experiments on Neutron Transport through Concrete Member and the Potential for the Use in Material Investigation

Abstract

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.

Importance of Atomic Composition and Moisture Content of Cement based Composites in Neutron Radiation Shielding

“…This solution eliminates the influence of granulometry on the results for both mechanical properties and radiation protection. For comparison, the results for a sample of standard cement mortar CEM I according to EN 196-1 and PCC mortar from Piotrowski and Skubalski [8] are presented. The compressive strength of concrete was evaluated and concrete from C20/25 to C40/50 was obtained.…”

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

“…The synergy effect was also taken into account. As in the experiment the neutron source was a Pu-Be and in final MCNP calculations for linear attenuation coefficient estimation the same source and the real geometry of experiment [11] were taken as a input data. The energy histogram used in MCNP simulations was taken from Harvey [13] as presented in Fig.…”

“…The details of experimental test setup was described in studies of Piotrowski et al [11]. The comparison was made on the base of linear attenuation coefficient [14,15] …”

“…It was found also by that PCC with 20% epoxy can effectively reduce overall deterioration of concrete especially those exposed to sea water [10]. Regarding shielding properties in a research on cement based mortars it has been demonstrated a significant benefit on neutron shielding properties of epoxy polymer addition as the PCC repair mortars exhibited superior properties in terms of both thermal neutron absorption and fast neutrons attenuation [11].…”

Photon Shielding Features of Quarry Tuff

“…Another designed material, known as NGSconcrete, polymers and standard cements mortars have been studied in their shielding features [18,19]. In these studies, the half value layer and the ten value layer were evaluated.…”