Environmental evaluation of natural radioactivity in soil near a lignite-burning power plant in Turkey

Natural radionuclides are released into the environment together with fly ash from the coal-burning power plant and cause an increase in the natural radioactivity in environmental samples. The study concerns to the evaluation the influence of Kangal lignite-burning power plant (LBPP) with a power of 457 MWe, which has been in operation since 1989, on natural radionuclide a concentration in surface soil samples around it. Activity concentrations of natural radionuclides (²²⁶Ra, ²³²Th, ⁴⁰K and ²²²Rn) in the soil samples, and emanation coefficient (EC) and mass (ER_M) and surface (ER_S) exhalation rate of radon were determined by using a gamma-ray spectrometer with an HPGe detector. The average values of ²²⁶Ra, ²³²Th, ⁴⁰K and ²²²Rn, EC, ER_M and ER_S were found as 37±5, 17±3, 222±30Bqkg^-1 and 9±1kBqm^-3, 12%, 12.1 µBq kg^-1 s^-1 and 7.1mBqm^-2 s^-1, respectively. Absorbed gamma dose rate in outdoor air and the corresponding effective dose rate from external exposure and excess lifetime cancer risk were estimated to evaluate radiological hazards for human population. The results revealed that the Kangal LBPP has caused a small increment in ²²⁶Ra concentration in the studied area. No influence was observed for ²³²Th and ⁴⁰K.

Investigation of cross sections of reactions used in neutron activation analysis

In this study, neutron incident reaction cross sections for some target nuclei such as 24Mg, 27Al, 28Si, 56Fe, and 63Cu used in neutron activation analysis have been investigated. The new calculations on the excitation functions of 24Mg(n, p)24Na, 27Al(n, p)27Mg, 27Al(n, α)24Na, 28Si(n, p)28Al, 56Fe(n, p)56Mn, and 63Cu(n, 2n)62Cu reactions have been carried out for incident neutron energies up to 20 MeV. In these calculations, the pre-equilibrium and equilibrium effects have been investigated. The pre-equilibrium calculations involve the new geometry dependent hybrid model and the full exciton model. Equilibrium effects are calculated according to the Weisskopf–Ewing model. In the present work, reaction cross-sections have been calculated by using empirical formulas developed for energies of 14–15 MeV. The calculated results are discussed and compared with the experimental data taken from the EXFOR database.

Investigation of the activity level and radiological impacts of naturally occurring radionuclides in blast furnace slag

The activity level and possible radiological impacts of naturally occurring radionuclides on the health of workers and members of the public, as a result of utilisation of blast furnace slag (BFS) samples as a substitute for aggregate in road construction were investigated by using a gamma-ray spectrometer and potential exposure scenarios given in Radiation Protection 122. The mean activity concentrations of the (226)Ra, (232)Th and (40)K in BFS samples were found to be 152.4, 54.9 and 183.1 Bq kg(-1), respectively. These values are compared with typical values measured in BFS samples from the European Union countries, which are 270, 70 and 240 Bq kg(-1) for (226)Ra, (232)Th and (40)K, respectively. The values of radium equivalent activity index calculated for BFS samples were within the recommended safety limits. The highest total annual effective doses evaluated as 0.9 and 0.4 mSv y(-1) for members of the public and workers, respectively, were lower than the annual limit of 1 mSv y(-1).