RADIOLOGICAL HAZARD INDICES OF GRANITIC ROCKS USED FOR THE CONSTRUCTION OF BUILDINGS FROM NUBA MOUNTAINS SUDAN.

This study was conducted to assess the level of radioactivity and the radiation hazards associated with granite rocks used for construction of buildings. The measurement of radioactivity content of the rock samples was performed with gamma-spectrometry equipped with Nal (TI) detector. From the results obtained in this study the average activity concentrations of 226Ra, 232Th and 40K were 20.64, 30.50 and 295.19 Bq kg-1, respectively. The absorbed dose rate in air at 1 m above ground level, the annual effective dose and the gamma index were determined with the aim to assess the possible radiological impact on inhabitants of dwellings built using such rocks. The mean value of the absorbed dose rate, the annual effective dose and the gamma index (Iγ) was 36.36 nGy h-1, 40.79 µSv y-1 and 0.51 µSv y-1, respectively. Radium equivalent activities, and external and internal hazard indices, were also calculated. These data indicated that the area of study lies within areas recognized as normal background radiation and the granite rocks are safe to be used as building material and other structural purposes.

Main results of the 2012 joint Norwegian-Russian expedition to the dumping sites of the nuclear submarine K-27 and solid radioactive waste in Stepovogo Fjord, Novaya Zemlya.

This paper reports the main results of the 2012 joint Norwegian-Russian expedition to investigate the radioecological situation of the Stepovogo Fjord on the eastern coast of Novaya Zemlya, where the nuclear submarine K-27 and solid radioactive waste was dumped. Based on in situ gamma measurements and the analysis of seawater and sediment samples taken around the submarine, there was no indication of any leakage from the reactor units of K-27. With regard to the radioecological status of Stepovogo Fjord, activity concentrations of all radionuclides in seawater, sediment and biota in 2012 were in general lower than reported from the previous investigations in the 1990s. However in 2012, the activity concentrations of (137)Cs and, to a lesser extent, those of (90)Sr remained elevated in bottom water from the inner part of Stepovogo Fjord compared with surface water and the outer part of Stepovogo Fjord. Deviations from expected (238)Pu/(239,240)Pu activity ratios and (240)Pu/(239)Pu atom ratios in some sediment samples from the inner part of Stepovogo Fjord observed in this study and earlier studies may indicate the possibility of leakages from dumped waste from different nuclear sources. Although the current environmental levels of radionuclides in Stepovogo Fjord are not of immediate cause for concern, further monitoring of the situation is warranted.