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- ArticleYalnız künye2021Experimental investigation of thermal energy storage efficiency using fin application with phase change material (pcm) under solar radiation
Acir, Adem; Canli, Mehmet Emin; Ata, Ismail; Uzun, Sinem; Tanürün, Himmet Erdi
In this paper, the energy storage behavior of the thermal energy storage unit (TESU) using phase change material (PCM) and copper fi ns under artifi cial solar radiation was analyzed experimentally. The experimental tests of the TESU were performed at three diff erent fi n numbers (n = 3, 5, and 7) and fi n thickness (t = 1, 1.5, and 2 mm) under variable solar radiations (q = 800, 900, and 1000 W/m2). The stored thermal energy of each TESU was calculated and compared with solar energy coming from a solar lamp. The highest thermal energy storage effi ciency was computed as 95.08% in Type-VIII (n = 7, t = 1 mm) TESU below 1000 W/m2 solar fl ux. The thermal energy storage effi ciency enhancement ratio (TESEER) was defi ned to understand the eff ects of n and t of the thermal energy storage effi ciency of TESUs. The highest TESEER was calculated as 1.68 in Type-VIII (n = 7, t = 1 mm) TESU below 1000 W/m2 solar radiation. In conclusion, the TESEER values were decreased with increasing fi n thickness, whereas its values were usually increased with the increase number of fi ns.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2021Evaluation of the al/, cu/, si/, ag/water nanofluid effects on heat transfer characteristics in vver-1200 loaded with plutonium-thorium-based fuel
Genc, Yasin; Uzun, Sinem; Acir, Adem
This study is aimed at investigation of the potential effects of various nanoparticles used in certain properties and ratios in the coolant of VVER-1200 power plant on thermal hydraulic performance. Criticality and thermal hydraulic analysis have been performed by using MCNP and COBRA-IV/PC code, respectively. The fuel ratio has been selected as 90% ThO2 + 10% reactor grade (RG)-PuO2. Al, Cu, Si, and Ag nanoparticles in proportions of 0.01% and 0.1% by volume have been mixed with reactor coolant water. The effects of adding nanoparticles into the coolant at two different ratios on the reactor criticality, departure from nucleate boiling ratio (DNBR), and thermal hydraulic performance have been investigated. It is observed that by adding nanoparticles into the coolant, the temperature rise along the hottest channel is higher compared to the case when only water is used as the coolant, whereas the criticality and DNBR have shown a decreasing trend. It can be concluded that combination of fuel made up of 90% ThO2 + 10% RG-PuO2 and nanofluid containing 0.1% volumetric ratio of Si nanoparticle could be used in VVER-1200 nuclear power plant and this combination could contribute to augmentation of thermal efficiency of the plant.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2021THERMAL ANALYSIS OF THE VVER-1000 REACTOR WITH THORIUM FUEL AND COOLANT CONTAINING Al2O3, CuO, AND TiO2 NANOPARTICLES
Acır, Adem; Uzun, Sinem; Genç, Yasin; Asal, Şulenur
The use of nanofluids has recently gained importance in studies carried out on increasing reactor efficiency with attention paid on safety factors in nuclear technology. Nanofluids used in reactor cooling water at certain properties and ratios generally use enriched UO2 as fuel. Through the discovery of thorium reserves and its use in nuclear technology, thorium has also become a candidate for being used as a fuel material in reactors. In this study, using ThO2 fuel and Al2O3, CuO, and TiO2 nanoparticles of the coolant in different ratios, the neutronic and thermal properties of the reactor, especially the criticality and temperature of coolant and DNBR as three leading parameters, were investigated. For the analyses, 5%, 10%, 15%, and 20% ThO2 was added to the reactor core containing 3.7% enriched UO2 fuel, and the analyses were performed adding 0.01%, 0.05%, and 0.1% volume of nanoparticles to the coolant water. Neutronic calculations were carried out with the help of MCNP code and COBRA-IV PC code was used for thermal analysis. The obtained results showed that by adding nanoparticles to coolant and using thorium as an additive to fuel the rise of coolant temperature can be augmented by 4.67 K compared to traditional combination of UO2 fuel and water while reactor remained within safety limits.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2020Investigation of Criticality and Relative Power Density Distribution in VVER-1000 Nuclear Power Reactor
Genç, Yasin; Uzun, Sinem; Acir, Adem
One of the most important elements of the design and safe operation of nuclear power reactors is the examination of the criticality and relative power density distribution. In this study, the neutronic performance analysis of the VVER-1000 containing the critical and relative power density distribution was calculated with the help of the MCNP neutronic code. Neutronic calculations were performed for four different fuel types. As a result of the calculations for each fuel assembly, criticality and relative power density distributions were obtained in the reactor core. The results obtained in this study were compared with the literature and it was seen that the critical and relative power density distribution values were similar.
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