Atomic scale simulations on LWR and Gen-IV fuel

Fundamental understanding of the behaviour of nuclear fuel has been of great importance. Enhancing this knowledge not only by means of experimental observations, but also via multi-scale modelling is of current interest. The overall goal of this thesis is to understand the impact of atomic interactions on the nuclear fuel material properties. Two major topics are tackled in this thesis. The first topic deals with non-stoichiometry in uranium dioxide (UO2) to be addressed by empirical potential (EP) studies. The second fundamental question to be answered is the effect of the atomic fraction of americium (Am), neptunium (Np) containing uranium (U) and plutonium (Pu) mixed oxide (MOX) on the material properties.UO2 has been the reference fuel for the current fleet of nuclear reactors (Gen-II and Gen-III); it is also considered today by the Gen-IV International Forum for the first cores of the future generation of nuclear reactors on the roadmap towards minor actinide (MA) based fuel technology. The physical properties of UO2 highly depend on material stoichiometry. In particular, oxidation towards hyper stoichiometric UO2 – UO2+x – might be encountered at various stages of the nuclear fuel cycle if oxidative conditions are met; the impact of physical property changes upon stoichiometry should therefore be properly assessed to ensure safe and reliable operations. These physical properties are intimately linked to the arrangement of atomic defects in the crystalline structure. The first paper evaluates the evolution of defect concentration with environment parameters – oxygen partial pressure and temperature by means of a point defect model, with reaction energies being derived from EP based atomic scale simulations. Ultimately, results from the point defect model are discussed, and compared to experimental measurements of stoichiometry dependence on oxygen partial pressure and temperature. Such investigations will allow for future discussions about the solubility of different fission products and dopants in the UO2 matrix at EP level.While the first paper answers the central question regarding the dominating defects in non-stoichiometry in UO2, the focus of the second paper was on the EP prediction of the material properties, notably the lattice parameter of Am, Np containing U and Pu MOX as a function of atomic fractions.The configurational space of a complex U1-y-y’-y’’PuyAmy’Npy’’O2 system, was assessed via Metropolis-Monte Carlo techniques. From the predicted configuration, the relaxed lattice parameter of Am, Np bearing MOX fuel was investigated and compared with available literature data. As a result, a linear behaviour of the lattice parameter as a function of Am, Np content was observed, as expected for an ideal solid solution. These results will allow to support and increase current knowledge on Gen-IV fuel properties, such as melting temperature, for which preliminary results are presented in this thesis, and possibly thermal conductivity in the future.Doctorat en Sciences de l'ingénieur et technologieinfo:eu-repo/semantics/nonPublishe

Investigation of Some Heavy Metals Accumulation in Muscle of Pike Perch (Stizostedion lucioperca, Linnaeus 1758) from Lake Beysehir, Turkey

WOS: 000338975300010This study was carried out in order to determine seasonally some heavy concentrations in pike perch (Stizostedion lucioperca) that is fished in Lake Beysehir, which is the third biggest lake of Turkey, consumed and exported. For this purpose, pikeperch seasonally obtained from fishermen in the region in 2011-2012. Heavy metal analyzes of pikeperch were carried out by using inductively coupled plasma optical emission spectrometry (ICP-OES). At the end of the study, minimum and maximum heavy metal concentrations in muscle of pike perch were detected as 0.008-0.047 mg kg(-1) for Cd, 0.033-0.226 mg kg(-1) for Co, 0.024-0.368 mg kg(-1) for Pb, 0.14-0.222 mg kg(-1) for Ni, 0.14-0.301 mg kg(-1) for Cr, 0.326-0.552 mg kg(-1) for Cu, 2.784-4.72 mg kg(-1) for Fe, 5.449-8.859 mg kg(-1) for Al, 15.85-26.497 mg kg(-1) for Zn, 0.215-0.311 mg kg(-1) for Mn. the obtained results were compared in terms of national limit values and international consumed and standart values

Investigations on mineral content in warty crab Eriphia verrucosa (Forskal, 1775) from the Rize Coast of Black Sea, Turkey

WOS: 000419096300011This study investigated the seasonal variations in mineral content of edible parts of male and female warty crab Eriphia verrucosa (Forskal, 1775) distributed along Rize Coast of Black Sea and compared the same with the limit values of mineral content for human consumption set by various national and international standards. the contents of Al, B, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni and P estimated during the present study did not exceed the limit values as per the national and international standards. However, Pb (0.25-0.70 mg kg(-1)), Se (0.29-0.75 mg kg(-1)) and Zn (43.86-72.59 mg kg(-1)) contents were found to be above the limit values. in terms of daily consumption values, it was found that, Al (1.86-3.35 mg kg(-1)), B (2.17-3.65 mg kg(-1)), Fe (2.80-6.44 mg kg(-1)) and Mo (0.01-0.02 mg kg(-1)) contents were within the limits as per all standards; while Ca, Cd, Cr, K, Mg, Mn, Na and P contents were above the limits prescribed by certain standards and Cu, Pb, Se and Zn contents were above the limits as per all the standards Most mineral contents of female crabs were higher than those of the males. Additionally, mineral content of the crabs was observed to increase during summer compared to other seasons

SEASONAL VARIATION OF FATTY ACID AND AMINO ACID COMPOSITIONS IN THE MUSCLE TISSUE OF ZANDER (SANDER LUCIOPERCA LINNAEUS, 1758) AND THE EVALUATION OF IMPORTANT INDEXES RELATED TO HUMAN HEALTH

WOS: 000401639300007In this study, the seasonal fatty acid and amino acid amounts in the muscles of the zander from Beysehir Lake, Turkey, and their important indices for human health were evaluated. It was found that aspartic acid, glutamic acid and lysine levels in zander were dominant among the amino acids. the ratio of essential amino acids (EAA) to non-essential amino acids (NEAA) was between 0.69 and 0.78. in all seasons, the polyunsaturated fatty acid (PUFA, 89.85-109.11 mg/100g) amount in zanders was higher than saturated fatty acids (SFA, 55.08-81.89 mg/100g) and monounsaturated fatty acids (MUFA, 29.16-78.89 mg/100g). It was determined that EPA, DHA and omega-3 rates were high. the fatty acid quality indices (AI, TI, FLQ, w6/w3, h/H) were found at proper levels for human health. Summing up the results, it was found that seasons influenced both the compositions of amino acids and fatty acids of zander

Lattice parameter of Am, Np bearing MOX fuel: An empirical potential study

An empirical potential study was performed for the americium (Am), neptunium (Np) containing uranium (U) and Plutonium (Pu) mixed oxides (MOX). The configurational space of a complex U1-y-y′-y″ PuyAmy′ Npy″O2 system was predicted by the rigid lattice Monte Carlo method. Based on the computing time and efficiency performance, the method was found to rapidly converge towards the optimal configuration. From that configuration, the relaxed lattice parameter of Am, Np bearing MOX fuel was investigated and compared with available literature data. As a result, a linear behaviour of the lattice parameter as a function of Am, Np content was observed.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Effects of different processing techniques on the carpet shell (Ruditapes decussatus Linnaeus, 1758)

KORAL, SERKAN/0000-0001-7424-2481WOS: 000364798700004In this study, the effects of different processing techniques on the food quality of carpet shells (Ruditapes decussatus, Linnaeus, 1758) were Investigated. Carpet shells were smoked, smoked-marinated, and marinated, and stored for 7 months at 2 +/- 1 degrees C. During the 210-day storage period, total volatile basic nitrogen, trimethylamine nitrogen, thiobarbituric acid, total mesophilic and psychrophilic aerobic bacteria counts, yeast-mold counts, and lactic acid bacteria counts for each group did not exceed acceptable limits, and coliform bacteria, E. coli, Staphylococcus aureus, Salmonella spp., or Listena spp. were not detected. However, sensory scores for texture, appearance, odor, and flavor decreased gradually over time. Based on the results of our sensory, chemical, and microbiological analysis, smoked, smoked-marinated, and marinated carpet shells can be safely consumed within 120, 150, and 180 days, respectively.Scientific Research Fund of Recep Tayyip Erdogan University (RTEUBAP)Recep Tayyip Erdogan University [2012.103.03.1]This study was supported by the Scientific Research Fund of Recep Tayyip Erdogan University (RTEUBAP) with project number 2012.103.03.1. We would like to thank their financial and technical support

THE EFFECT OF DEPURATION ON BACTERIAS, MINERAL MATTERS, FATTY ACIDS AND AMINO ACIDS IN CARPET SHELL (RUDITAPES DECUSSATUS LINNAEUS, 1758) AND THE EVALUATION OF QUALITY INDEXES IN TERMS OF HUMAN HEALTH

KORAL, SERKAN/0000-0001-7424-2481WOS: 000392555800067In this study, we have evaluated the effect of depuration on the bacterias, the mineral matters, the fatty acids and the amino acids in the carpet shells and the quality indexes in terms of human health. the carpet shells that underwent the depuration process for a total of 72 hours in a closed loop system were analyzed every 12 hours. There was a significant decrease in the total number of bacteria depending on the duration of depuration. E. coli, Salmonella spp., Staphylococcus aureus, Listeria monocyto genes,Vibrio parahaemolyticus and Vibrio cholera could not be determined in the carpet shells during depuration. 48-hour processing time was determined to be significant for a decline in Co, Fe, Al, Cu, and Mn levels due to depuration in the carpet shells. Zn, Cu, Ni and Cr levels were found to remain in the national and international limit values during the study. Al and Mn levels were envisaged to be appropriate for all the thresholds specified in terms of human health. the values of total essential amino acids (Sigma EAA) and non-essential amino acids (Sigma NEAA) at the end of depuration process were higher than their initial values and the EAA/NEAA ratio was determined between 0.82-1.09. It was found in the carpet shells during depuration that polyunsaturated fatty acids (PUFA) were between 57.64-58.88%, saturated fatty acids (SFA) were between 23.72-25.46% and monounsaturated fatty acids (MUFA) were between 8.51-9.75%. EPA, DHA and omega-3 levels which play an important role in human nutrition were found to be high. Moreover, the quality indexes of the fatty acid (AI, TI, FLQ, w6/w3, h/H) were determined to be at appropriate values for human health

The Effect of Depuration on Metals, Bacteria, and Nutrition inVenus verrucosafrom the Aegean Sea: Benefit and Risk for Consumer Health of Warty Venus

karsli, baris/0000-0002-3944-6988; caglak, emre/0000-0002-7376-1359; KORAL, SERKAN/0000-0001-7424-2481WOS: 000544470000009In this study, the effect of the depuration period on proximate composition, metals, fatty acids, and bacteria in the edible tissue of warty venus (Venus verrucosa) collected from Izmir Bay in the Aegean Sea was investigated. in addition, benefit and risk for human health associated with the consumption of warty venus were determined by atherogenic index (AI), thrombogenic index (TI), polyene index (PI), fish lipid quality (FLQ), target hazard quotient (THQ), and hazard index (HI). the depuration process did not show a significant (P> .05) effect on proximate composition, except for ash. the depuration process was successful in reducing bacteria growth and the concentrations of all metals, except for copper. Total aerobic mesophilic bacteria count of 1.94 log CFU/g in the fresh samples was uncountable at 24 h of depuration. the concentrations of cadmium, lead, copper, iron, and zinc were below the limit values allowed for safe consumption. the analyzed metals were safe for human consumption based on provisional tolerable weekly intake (PTWI), THQ, and HI. Significant variations were also observed in the fatty acid values depending on the depuration periods (P< .05). the n3/n6 and polyunsaturated/saturated fatty acid ratios were greater than those recommended by the FAO/WHO. Moreover, the AI and TI of samples were under established limits

Effects of the Depuration Process on Microbiological Quality and Nutritional Composition of Mediterranean Mussel (Mytilus galloprovincialis Lamarck, 1819)

KORAL, SERKAN/0000-0001-7424-2481WOS: 000406555500010In this study, the effects of the depuration period on Mediterranean mussel (Mytilus galloprovincialis L., 1819), collected from Bandirma Harbor Area by the Sea of Marmara, were investigated. Distinctive changes were found to exist in the percentage of moisture, protein, fat, and ash content. the process of depuration was determined to have an effect on the number of total aerobic mesophilic/psychrophilic bacteria. Salmonella spp., Listeria monocytogenes, Vibrio parahaemolyticus, Vibrio cholera, Escherichia coli, and Staphylococcus aureus could not be identified during the study. the substances of aluminum, iron, zinc, copper, manganese, nickel, cadmium, chromium, lead, and potassium were determined to decrease in the Mediterranean mussel from the baseline to the end of the depuration. It was found that the process of depuration has a positive effect on alanine, phenylalanine, lysine, tyrosine, valine, leucine, and isoleucine; a negative effect on aspartic acid, glutamic acid, threonine, proline, and arginine and no effect on methionine, histidine, glycine, and serine. the total saturated fatty acids, total monounsaturated fatty acids, and total polyunsaturated fatty acids at the end of depuration were found to be 29.29%, 12.51%, and 45.57%, respectively, and the change in the amount of polyunsaturated fatty acids was found to be significant (p < 0.05).Recep Tayyip Erdogan University Scientific Research Projects Coordination UnitRecep Tayyip Erdogan University [2011.103.03.2]This study was supported by Recep Tayyip Erdogan University Scientific Research Projects Coordination Unit (2011.103.03.2)

Effect of Modified Atmosphere Packaging on Quality and Shelf Life of Salted Bonito (Sarda sarda)

WOS: 000308131600004In this study, the fresh meat of bonito (Sarda sarda) was used to make lakerda, which is a type of salted fish (Turkish traditional product). The lakerda was packaged in plastic film (A), vacuumed (VP), placed in modified atmosphere packaging (MAP; M1 = 80%/20% CO2/N-2, M2 = 65%/35% CO2/N-2, M3 = 30%/60%/10% CO2/N-2/O-2), and stored at 2 +/- 1 degrees C. Microbiological, chemical, sensory, and color analyses were conducted to determine the changes in quality. Total viable bacteria counts did not exceed the limit of consumption (7 log cfu/g) for all groups on Day 31. Total volatile basic nitrogen (TVB-N) and trimethylamine-nitrogen (TMA-N) values of M1, M2, and M3 remained lower than the proposed acceptability limits of 35 and 12 mg N/100 g, respectively, up to 31 days of storage. However, VP lakerda samples exceeded TVB-N limits after 31 days of storage, whereas A lakerda samples exceeded after 8 days of storage. In our study, sensory analysis determined the shelf life of modified atmosphere packaged lakerda. When Group A is compared with the other groups, MAP and VP lengthened the shelf life of lakerda by 23 days