In this manuscript an improved sorbent based on modified exfoliated carbon nanoplatelets, applied in the removal of ammonium from aqueous samples, is presented. This sorbent showed better efficiency in comparison with the previous one obtained in our group for ammonium removal, the values of the maximum sorption capacity being improved from 10 to 12.04 mg/g. In terms of kinetics and sorption characteristic parameters, their values were also improved. Based on these results, a sorption mechanism was proposed, taking into account ion-exchange and chemisorption processes at the surface of the oxidized exfoliated carbon nanoplatelets. Future applications for simultaneous removal of other positive charged contaminants from natural waters might be possible.

Starting with 2010 and until 2020, the VVR-S nuclear research reactor from Magurele, Romania, is in the decommissioning process. The reactor aluminum assembly contains the internal vessel which represent the main component of the reactor. In order to identify the optimum technological methods of dismantling and cutting, the initial radiological characterization of the reactor vessel was conducted. Modern methods like plasma jet, diamond wire cutting, shredding with a Brokk 160 demolition robot were used in this process. Safety aspects for optimizing radiation protection of operating personnel were analyzed and innovative solutions were identified. The lessons learned from the reactor vessels dismantling were presented.

The aims of this study were to determine the radon concentration in natural mineral and tap water and to estimate the resulting ingestion doses received by adults. Physical-chemical characteristics of water samples have also been investigated. In the last years have been an increase of water consumption of both, natural mineral and tap, many sources and producers being available on the market. Thus, the physical-chemical and radiologic parameters of water must be in compliance with the Drinking Water Directive (DWD). Thus, the study presents an assessment of the radioactivity due to 222Rn and 3H in several mineral natural water samples from the north region of Romania, but also in several tap water samples. The methods used were based on gamma spectrometry, gross alpha-beta measurements and beta spectroscopy, but also ICP-MS for chemical parameters. The results of this work showed that the geology and rock types clearly influence the water radon concentration. The radon concentration is lower in the water that passes through sedimentary rocks than that passing through granitic rocks. An important aspect of this work is to provide reliable information regarding radon and tritium concentrations. Radon concentration varied between 0.15±0.05 Bq/L and 11.35±2.97 Bq/L in the natural mineral water samples and between 0.17±0.05 Bq/L and 8.51±2.34 Bq/L in the tap water samples. An estimation of annual effective radiation dose based on the sample results was also made. Calculated values for ingestion dose due to regular consumption of water does not induce a health risk because of the intake of various radionuclides contained in the water. The maximum values being of 47.38 µSv/y. The determined values for the collected samples are below recommended reference levels, but more important aspect is that this study emphasise environmental sustainability in the investigated area.

The VVR-S nuclear research reactor owned by Horia Hubulei National Institute of Physics and Nuclear Engineering, has functioned between 1957 and 1997 at a nominal thermal power of 2 MW, using less-enriched nuclear fuel (10%), type EK-10, and highly enriched fuel (36%), type S-36. The reactor control was carried out by means of nine rods placed in the central part of the core. Four rods were used for the manual control of power, one for automatic control, three rods for reactor safety (emergency rods) and one for the fine control of power. One of the high hazard operations was the dismantling of the activated-contaminated control rods. Because of a higher radiological risk, simulation was performed to determine the expected maximum dose. The maximum gamma dose rate obtained using simulated results was 3.5 Sv/h, for the highly activated rod. In the real measurement, when the work was performed, the maximum gamma dose rate was 3 Sv/h.90 Sr+ 90 Y are expected to be present in the control rods radioactivity.