CALCULATION PROGRAM FOR THE PROCESSING OF LOW-CONCENTRATED TRITIUM AND DEUTERIUM WASTE THROUGH THE CECE ISOTOPIC SEPARATION PROCESS

Within the research conducted at our Institute of Cryogenic and Isotopic Technologies (ICSI), is developed a project entitled "Innovative CECE process solution to promote a new technology for decontamination of liquid waste, tritium low concentrated and deuterium recovery”. The main objective of the project carried out within our team is to promote an innovative solution of CECE isotopic separation process (Combined Electrolysis and Catalytic Exchange), part of a new technology for decontamination of liquid waste, poorly concentrated in tritium, generated by nuclear reactors, ensuring increased recovery of the isotope deuterium and tritium. This paper presents the current stage of an innovative CECE isotopic separation process solution, and also the mathematical model developed for the simulation of hydrogen isotope separation processes through the CECE process and a theoretical analysis based on numerical data resulting from the simulation of two CECE plant operating mode.

REVIEW OF THE CURRENT INITIATIVES FOR CARBON DIOXIDE UTILIZATION TECHNOLOGIES IN EUROPE AND THE PROSPECTS FOR ROMANIA – PART I

Carbon Capture, Utilization, and Storage (CCUS) technologies comprise a set of proposed technological solutions (i.e. methods, measures, implementations, and policies) that seek to trap carbon dioxide – the main form of carbon carrier molecule responsible for the greenhouse effect, originating from human economic activities, and destabilizing the planetary climate – before its release into the atmosphere. The aim and function of CCUS manifest as either preventive measures that lock carbon dioxide permanently underground or in other suitable media (Carbon Capture and Storage, CCS), or as redirecting processes that feed it back to augmented industrial cycles for manufacturing products with positive financial impacts (Carbon Dioxide Utilization, CDU). Following recent initiatives at the European level and in view of the larger picture unfolding at the global theater, this digest review aims to deliver the main points, considerations, and dynamics that drive and formulate modern CCUS initiatives, focusing more on the recently surfaced CDU front. We will explore proposed pathways for materializing CDU by looking carefully on unfolding examples from such global and European arenas. We will then scrutinize plausible scenarios for transposing CDU to Romania to ask – and hopefully answer – the right questions as to how such scenarios can materialize.

AN ALTERNATIVE FOR VALORIZATION OF WASTES AS ENERGY SOURCE

The efficient use of renewable energy resources is one of the most important elements of energy sustainability at the European Union level. The growing demand for energy will continue to support the use of other materials as resources of energy than conventional ones, coal, crude oil and natural gas. This paper investigates the feasibility of valorizing wastes with energetic potential in a multi-component alternative solid fuel. Biomass - vegetable waste (BW), meat and bone meal (MBM) and slag/bottom ash from lignite combustion, in combination with a low-rank, lignite, was used to prepare tri-component mixtures (MBM+Lignite +Slag and MBM+BW+Lignite) indifferent variable proportions, and further characterized to assess their potential for use as energy source. The thermal behavior of the mixtures was assessed by thermogravimetric analysis; the resulting ashes were characterized by scanning electron microscopy.Also, the environmental impact as emissions level after their combustion was considered. In terms of an effective way of removing wastes (e.g. slag/bottom ash and MBM), the most promising proposed solid mixture was the combination MBM(50%): Lignite(25%): Slag (25%), with a high energetic value, > 2700 kcal/kg, a volatile matter content > 35 %wt, and the ash in half amount compared to its initial mass. Thestudy’s findings illustrate the possibility of turning solid waste to raw material by converting them into energy, and promote the development of long-term waste management and recovery solutions.

INFLUENCE OF WATER EXTRACTION METHODS FROM ENVIRONMENTAL SAMPLES ON MEASURED TRITIUM LEVEL

In order to validate the laboratory routine procedure of tritium activity concentration determination in tissue free water of environmental samples, parallel measurements were performed in water extracted from wild vegetation by two methods: azeotropic distillation and lyophilization (recommended by a French standard method). The sample humidity was established using the drying procedure to constant mass of the sample, and isotopic effect that may occur during lyophilization procedure was investigated by deuterium ratio determination in sample and extracted water. Traces of toluene in extracted water by azeotropic distillation made deuterium ration determination useless.

TEMPORAL EVOLUTION OF GREENHOUSE GAS EMISSIONS IN EUROPEAN UNION (EU-28): A PERSPECTIVE ON ROMANIA

The European mitigation strategy for combatting climate change requires up-to-date knowledge about the environmental effects of greenhouse gas (GHG) emissions at the national scale. As a strong response to the consequences of climate change, the European Union has imposed on the member states an obligation to achieve the goals set out in the climate and energy package, which were aimed at reducing emissions. Therefore, underlying the trends of GHG emissions is essential when establishing climate change mitigation measures. This study identify the structure and dynamics of the GHG emissions of the six sectors of the European economies, over 27 years, and reveal the significance, direction, rate, and drivers of the observed trends using the method of modifying the absolute mean. The results indicate a decrease in the GHG emissions in the EU-28 by an average of 1% annually, which can be explained by a mixt factors, such as resize of the industry, improved energy efficiency, the growing share of renewables and less use of carbon fuels. Moreover, through the environmental policies adopted in the last decade, was observed that the GHG emissions level in 2017 had declined by approximately 25% in comparison with the reference (1990) and by approximately 17% by 2005. From the 28 EU countries (EU-28), Romania produced 4.2% of the total EU-28 GHG emissions in 1999, which decreased to 2.7% in 2005 and reaching 2.3% in 2017. Romania contributed to 14% of the average annual decrease in emissions. This evidence highlights the additional support for further reduction beyond that required for climate change mitigation.

TRITIUM DETERMINATION FROM WINE SAMPLES USING LIQUID SCINTILLATION COUNTING

Tritium measurement from aqueous fraction of the wines of known vineyard can be a useful tool in reconstruction of the tritium activity in different areas and makes possible to date the time of the harvest of the grapes. The goal of this study was to develop a suitable method for purification of the aqueous phase from the wine samples, obtained from different type of wines, in order to determine tritium activity concentration using liquid scintillation counting. In this work the influence of the purification method applied to the aqueous samples resulted from wine distillation was assessed by deuterium and tritium measurements, content of organic carbon, pH and conductivity. The most reliable purification method used for wine aqueous fractions, according with the results obtained for pH, and total organic carbon content is chemical treatment followed by lyophilization.

THE CONTRIBUTION OF ROMANIA TO CLIMATE CHANGE – THE EFFECTS OF ACCOUNTING THE GHG EMISSIONS FROM LAND USE, LAND-USE CHANGE AND FORESTRY (LULUCF)

This study aimed to analyze Romanian (RO) involvement in the LULUCF sector by considering the Intergovernmental Panel on Climate Change (IPCC) good practice guidance (GPG). Trends were assessed using the Mann-Kendall (MK) test for trend estimation to determine the total greenhouse gas (GHG) (GHGCO₂-eq.) emissions/ removals. The results emphasized the increasing average annual levels of emissions/removals in both the EU-28 and RO when the subperiods from 1990-2005 and 2005-2017 were analyzed. Kendall’s analysis of GHG removal showed a positive trend in Romanian GHG removals, and no trend was observed for the EU-28. In comparison, the emissions indicated an increasing trend for RO and a decreasing trend for the EU-28. The GHGCO₂-eq. generated by the LULUCF sector decreased to an average annual rate of 0.5% per year in the EU-28. In Romania, these emissions increased by approximately 0.2% per year on average. Between 1990 and 2017, the CO2 total absorption increased to 0.9% per year. The methane absorption also increased by 11.7% per year, and no significant increasing trend was observed for methane. The dynamics of GHGCO₂-eq. emissions/removals in RO and LULUCF sectors showed that settlement had decreased in wetlands, and settlement of other land areas had increased. Assessing GHG gas emissions is essential for allowing each sector to promote specific strategies, policies and action plans. This will improve the national-level monitoring of the LULUCF sector and make this information more accessible to decision makers by raising awareness of the Romanian position within the EU-28

PRELIMINARY DEVELOPMENT OF A CONCEPTUAL MODEL OF MATRIX HEAT EXCHANGER

While the basic principles of thermodynamics have remained the same, the necessity for heat exchangers to have good effectiveness in a small volume is constantly growing. Heat exchangers type Matrix Heat Exchanger (MHE), which can meet these requirements, does not have an optimal design variant for its use. These heat exchangers have been approached for 60 years, by many researchers, currently offering only an overview of the process. The mechanism of heat transfer in a matrix heat exchanger is complex, having three different thermal convection paths as well as thermal conduction through two different surfaces. This paper presents the simulations performed in ANSYS Workbench, combining all these heat transfer modes, for developing an optimal model of a perforated plate matrix heat exchanger, used for the pre-cooling of a hydrogen isotopes stream mixture, for purification purposes, as well as, for preparing the inlet temperature in cryogenic distillation columns of hydrogen isotopes.