Ahmet Erdal Osmanlioglu

Utilization of coal fly ash in solidification of liquid radioactive waste from research reactor

In this study, the potential utilization of fly ash was investigated as an additive in solidification process of radioactive waste sludge from research reactor. Coal formations include various percentages of natural radioactive elements; therefore, coal fly ash includes various levels of radioactivity. For this reason, fly ashes have to be evaluated for potential environmental implications in case of further usage in any construction material. But for use in solidification of radioactive sludge, the radiological effects of fly ash are in the range of radioactive waste management limits. The results show that fly ash has a strong fixing capacity for radioactive isotopes. Specimens with addition of 5–15% fly ash to concrete was observed to be sufficient to achieve the target compressive strength of 20 MPa required for near-surface disposal. An optimum mixture comprising 15% fly ash, 35% cement, and 50% radioactive waste sludge could provide the solidification required for long-term storage and disposal. The codisposal of radioactive fly ash with radioactive sludge by solidification decreases the usage of cement in solidification process. By this method, radioactive fly ash can become a valuable additive instead of industrial waste. This study supports the utilization of fly ash in industry and the solidification of radioactive waste in the nuclear industry.

Removal of radioactive contaminants by polymeric microspheres

ABSTRACT Radionuclide removal from radioactive liquid waste by adsorption on polymeric microspheres is the latest application of polymers in waste management. Polymeric microspheres have significant immobilization capacity for ionic substances. A laboratory study was carried out by using poly(N-isopropylacrylamide) for encapsulation of radionuclide in the liquid radioactive waste. There are numbers of advantages to use an encapsulation technology in radioactive waste management. Results show that polymerization step of radionuclide increases integrity of solidified waste form. Test results showed that adding the appropriate polymer into the liquid waste at an appropriate pH and temperature level, radionuclide was encapsulated into polymer. This technology may provide barriers between hazardous radioactive ions and the environment. By this method, solidification techniques became easier and safer in nuclear waste management. By using polymer microspheres as dust form, contamination risks were decreased in the nuclear industry and radioactive waste operations.

Management of spent sealed radioactive sources in Turkey.

Spent radioactive sources (SRS) have been generated from industrial applications, research, and medicine in Turkey. In this study, management of SRS (60Co, 137Cs) at Cekmece Waste Processing and Storage Facility (CWPSF) is described. Eleven 137Cs sources (total 851 GBq) and four 60Co sources (total 27.75 GBq) that had been used as levels and density gauges were conditioned. Reinforced metal drums (200 L in volume) and cement matrix were used for conditioning of these sources. In this way, greater confinement was achieved for long-term storage. Maximum dose rates at the surface of the conditioned waste package were determined. In addition to information about conditioning stages of the sources, various calculations that have been done for shielding are presented. Surface dose rates of the waste packages were 1.60 mSv h−1 for 137Cs and 1.63 mSv h−1 for 60Co. Measurements of the final waste packages were presented to fulfill the requirements (<2 mSv h−1) of transportation according to regulations for the safe transport of radioactive material.

Immobilization of radioactive borate liquid waste using natural diatomite

AbstractIn this article, influence of diatomite as a natural adsorbent in immobilization of radioactive borate liquid waste in the cement-diatomite matrix was investigated. Cylindrical concrete mixtures were prepared with different amounts of diatomite additives at three different w/c values. Mechanical strength tests were carried out to determine the uniaxial compressive strength of the samples. A new dynamic column type leaching tests were applied to the solidified waste forms, and leach rates of 137Cs and 60Co were determined according to different diatomite additives. The experimental results indicated that the increasing of the diatomite additive amounts resulted high isolation performance of the solidified waste form. However, the results revealed that mechanical strength decreases with increasing borate diatomite amount. Results show that 9% amount of natural diatomite is effective as an admixture of the cementation process for achieving long-term stability of solidified borate waste. Optimum stren...

Migration test column for decontamination of radioactive liquids by using natural tuff

AbstractThis study aims to evaluate the feasibility of using natural tuff found in the middle Anatolian region of Turkey for the removal of radioactivity from liquid radioactive wastes. Block samples that were collected from four different tuff deposits were first crushed to obtain particles with various sizes. The samples were then treated with low-level liquid radioactive waste in laboratory conditions. The effect of particle size on the adsorption performance of the tuff samples was studied for four types of radionuclides (241Am, 134Cs, 137Cs, and 60Co). The removal rates of radioactivity by the tuff samples having five different aggregate sizes (diameters of 4, 2.8, 2, 1, and 0.7 mm) were determined by the decrease in radioactivity concentration of the passed liquid discharge. In addition, the specific retention, saturation, and adsorption rates of the samples were also investigated. For most of the radionuclides, up to 50% saturation level and 70% specific retention were observed while the optimum re...

Characterization of Radiological Hazardous Effects of Metal Scraps in Turkey

AbstractThe main objective of this paper is to determine the radiological hazard level of various commercial scrap piles in Turkey. Samples were taken from metal scrap yards near the city of Istanbul, Turkey. In this study, radioactivity measurements were carried out on these samples. The activities of Ra226, Th232, K40, and Pb210 were determined in the laboratory by gamma-ray spectrometry. The highest Ra226, Th232, K40, and Pb210 activities were found to be 8,735, 465, 524, and 1,264  Bq  kg-1, respectively, in residues of technologically enhanced, naturally occurring radioactive material (TENORM) scraps. Radiation doses due to gamma exposure and radon emanation from residues were determined. Site-specific test results were determined to be less than the exemption limits for external radiation. According to these results, external radiation doses were less than 300  μSv/year for workers. The main factors due to radon inhalation were based on measured effective radium content, mass, and areal exhalation r...

Indoor Radon Measurement in Van

In this study, indoor radon concentrations obtained from the radon surveys conducted in the Van. Radon monitoring was performed by applying a passive, time‐integrating measuring technique. For this purpose, CR‐39 nuclear track detectors were installed in dwellings for 2 months. After the monitoring period, detectors were collected. In order to make the alpha tracks visible, chemical etching was applied to the exposed detectors. Nuclear track numbers and the corresponding indoor radon concentrations were determined. Annual effective dose equivalents and the risk probabilities caused by indoor radon inhalation were calculated, and the found results compared with the indoor radon concentrations’ data measured in different provinces of Turkey.