The formation of explosive gas mixtures due to the evolution of hydrogen from concrete structures for radiation protection of nuclear power buildings should be taken into account when designing and operating them. However, this requires methods for estimating and predicting the radiation evolution of hydrogen. This paper was done due to the lack of analytical methods for determining the gas evolution from concrete and their components under the influence of gamma radiation. In the work, based on the available experimental data, the model was selected, checked, and adjusted for an analytical description of the process of hydrogen evolution from concrete on aggregates that do not contain water under the influence of gamma radiation. When selecting the model, it was assumed that the evolution of hydrogen from concrete on aggregates that do not contain water under the effect of gamma radiation is mainly due to the radiation decomposition of evaporable water (free water and adsorbed water) from hardened cement paste (cement stone) and is determined by the amount of evaporable water in the material and the power of the absorbed dose of gamma radiation. It was taken into account that the amount of evaporable water during irradiation decreases with increasing time and temperature of irradiation. Verification of the possibility of using the selected model, its necessary adjustment and determination of the main parameters of this model was performed on the basis of available experimental data on the evolution of hydrogen from Portland cement stone under the influence of gamma radiation. We used experimental data on the release of hydrogen and water from cement stone containing and practically not containing evaporable water when irradiated with gamma rays with an average energy of 1.25 MeV at the absorbed dose rate of 0.87 kGy/h, 3.84 kGy/h and 7.05 kGy/h at temperatures of 25, 40 and 60 °C for up to 2 months. The dependence of the model parameters on the absorbed dose rate of gamma radiation and the irradiation temperature is shown. For cement stone dried at 120 °C to remove evaporable water, the amount of residual evaporable water (residual evaporable water or decomposed chemically bound water) was studied and determined.

We present experiments on the slow growth of a single crack in a fax paper sheet submitted to a constant force F . We find that statistically averaged crack growth curves can be described by only two parameters: the mean rupture time τ and a characteristic growth length ζ. We propose a model based on a thermally activated rupture process that takes into account the microstructure of cellulose fibers. The model is able to reproduce the shape of the growth curve, the dependence of ζ on F as well as the effect of temperature on the rupture time τ . We find that the length scale at which rupture occurs in this model is consistently close to the diameter of cellulose microfibrils.c EDP Sciences Article published by EDP Sciences and available at http://www.edpsciences.org/epl or http://dx.

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The results of measurements of the dose rate from γ radiation along the perimeter, at operating gates, and near the grounds of the Russian Science Center Kurchatov Institute are presented. The computed dose isolines for actual radionuclide emissions from the exhaust stacks of the Institute's objects are presented. The results show that the observed levels are identical to the analogous levels on average over Moscow. This shows that living next to Kurchatov Institute is no more dangerous than in any other region of Moscow.A large nuclear-type research object -the Russian Science Center Kurchatov Institute -has been operating within the Moscow city limits since 1943. The Institute is located in Moscow's northwest administrative district near the metro station Oktyabrskoe Pole. In addition to the main site (about 100 ha), the Institute possesses an auxiliary site (about 4 ha) between the Oktyabr stadium part (Zhivopisnaya St.) and the mouth of the Sobolevskii brook, which flows into the Moscow river. The object located on this site is called the Gazovyi Zavod.Research nuclear reactors with thermal power from several to tens of thousands of kW(t) operated at the Institute for many years. Some of them (F-1, OR, IR-8, and others) are still operating. Together with reactors, stands of nuclear critical assemblies, cyclotrons and other charged-particle accelerators, experimental laboratories, and facilities using sources ionizing radiation were built at the Institute.The operation of such facilities inevitably raises questions of protection from their direct radiation, gas-aerosol and liquid discharge emissions, and collection and removal of solid radioactive wastes. It is important to provide radiological protection to the staff working at the facilities as well as to people living in the surrounding region.Screens (concrete, metal, water jackets) were used as protection from direct radiation; high-level facilities were placed in deep, hermetic, foundation pits below ground level. Liquid radioactive wastes were directed through a special drainage system to a special water purification plant located near the mouth of Sobolevskii brook. The gas-aerosol emissions were decontaminated by multistep systems of rough-and fine-purification filters using Petryanov cloth (Fig. 1).Since the question of liquid wastes was solved, we shall dwell in greater detail on the removal of solid radioactive wastes, gas-aerosol emission, and the equivalent dose rate of γ radiation around the Institute.Prior to the beginning of the 1970s, radioactive wastes were collected in hermetic underground repositories on an organized temporary storage site. In 1974, the wastes started to be removed to a site of the Moscow Scientific and Industrial