Through diffusion study on Olkiluoto veined gneiss and pegmatitic granite from a structural perspective

MRS Advances ◽  
2016 ◽  
Vol 1 (61) ◽  
pp. 4041-4046 ◽  
Author(s):  
Mikko Voutilainen ◽  
Jussi Ikonen ◽  
Juuso Sammaljärvi ◽  
Jukka Kuva ◽  
Antero Lindberg ◽  
...  
Keyword(s):  
Pore Structure ◽  
Power Plants ◽  
Spent Nuclear Fuel ◽  
Knudsen Diffusion ◽  
Effective Diffusion ◽  
Crystalline Bedrock ◽  
Through Diffusion ◽  
The Difference ◽  
Micrometer Scale ◽  
Pegmatitic Granite

ABSTRACTSpent nuclear fuel from Finnish power plants is planned to be deposited deep in the crystalline bedrock in Olkiluoto, Finland. The bedrock needs to be well characterized to assess the risks inherent to the long term safety of the site. In the bedrock the possibly released radionuclides are mainly transported by water conducting fractures and their transport is retarded by diffusion and sorption. In porous materials these properties are typically linked to microscopic pore structure (pore size distribution, tortuosity and constrictivity) and chemical nature of the minerals and groundwater.In this work transport properties of veined gneiss (VGN) and pegmatitic granite (PGR) samples from Olkiluoto were studied using various through diffusion experiments and the C-14-PMMA autoradiography. Through diffusion experiments were performed on rock cores using HTO and 36Cl in water phase and He in gas phase as tracers. The effective diffusion coefficients (De) determined for the VGN were found to be dependent on the tracer molecule (De(HTO) < De(He) < De(Cl)) whereas for the PGR such a dependence was not found. The porosity distributions determined by the C-14-PMMA autoradiography revealed the difference in the pore structure between the samples. The porosity of VGN consists mostly of grain boundary pores and pores between biotite lamellae. Due to a high content of nanometer scale pores anion exclusion affected the results of 36Cl and Knudsen diffusion the ones of He for VGN. Furthermore, in the PGR micrometer scale intra- and intergranular fissures form a connected network for diffusive transport and thus all tracers diffuse at the same rate.

Investigation of mineralogy, porosity and pore structure of Olkiluoto bedrock

2014 ◽  
Vol 1665 ◽  
pp. 31-37 ◽  
Author(s):  
Juuso Sammaljärvi ◽  
Antero Lindberg ◽  
Jussi Ikonen ◽  
Mikko Voutilainen ◽  
Marja Siitari-Kauppi ◽  
...  
Keyword(s):  
Pore Structure ◽  
Nuclear Power ◽  
Power Plants ◽  
Spent Nuclear Fuel ◽  
Mean Value ◽  
High Porosity ◽  
Rock Matrix ◽  
Crystalline Bedrock ◽  
Rock Heterogeneity ◽  
Polarized Microscopy

ABSTRACTSpent nuclear fuel from TVO's (Teollisuuden Voima Oy) and Fortum's nuclear power plants will be deposited deep in the crystalline bedrock in Olkiluoto, Western Finland. The bedrock needs to be well characterized to assess the risks inherent to the waste disposal at the site. If radionuclides (RN) are transported, it happens via water conducting fractures. Retardation may occur either by diffusion into stagnant pore water or by immobilization on mineral surfaces of the rock matrix.RN’s retardation from flowing water is linked to parameters defining porosity and microscopic rock pore structure, such as pore size distribution, connectivity, tortuosity and constrictivity, and by the mineralogy and chemical nature of the minerals and charge of the pore surfaces.In this work, centimeter scale rock cores from Olkiluoto were investigated. The work is part of the in situ project REPRO (Experiments to investigate Rock Matrix Retention Properties) where the diffusion and sorption of RN are studied experimentally. Porosity and pore structures were characterized with the PMMA autoradiography method and polarized microscopy, which was used also to ascertain the mineralogy of the samples.The results show that the rock from the REPRO site has low porosity with a mean value of 0.5% and a range of 0.1-1.5%. Rock heterogeneity explains the variation of porosity values. Correlation between the porosity and the mineralogy was found. Areas of high porosity correspond to areas of altered minerals, such as cordierite, biotite and plagioclase, which cover spatially between 10 and 20% of the rock volume

Laboratory scale advection-matrix diffusion experiment in Olkiluoto veined gneiss using H-3 and Cl-36 as tracers

MRS Advances ◽  
2017 ◽  
Vol 2 (12) ◽  
pp. 655-660 ◽  
Author(s):  
Mikko Voutilainen ◽  
Pekka Kekäläinen ◽  
Jukka Kuva ◽  
Marja Siitari-Kauppi ◽  
Maarit Yli-Kaila ◽  
...  
Keyword(s):  
Power Plants ◽  
Spent Nuclear Fuel ◽  
Effective Diffusion ◽  
Core Sample ◽  
Matrix Diffusion ◽  
Diffusion Experiment ◽  
In Situ Experiment ◽  
Crystalline Bedrock ◽  
In Situ Conditions

ABSTRACTSpent nuclear fuel from Finnish power plants is planned to be deposited deep in the crystalline bedrock. The bedrock needs to be well characterized to properly assess the risks inherent to the long term safety of the site. In the bedrock the possibly released radionuclides are assumed to be mainly transported by water conducting fractures and their transport is retarded by matrix diffusion and sorption. In this work transport properties of an 80 centimeters long veined gneiss drill core sample from Olkiluoto was studied using an advection-matrix diffusion experiment, which was developed to demonstrate the effect of rock matrix for transport of radionuclides in an advective fracture. The experiment was performed using H-3 and Cl-36 as tracers, and effective diffusion coefficients (De) of (1.7 ± 0.7) × 10-13 m2/s and (1.4 ± 1.0) × 10-14 m2/s and porosities of 1.1 ± 0.3 % and 0.23 ± 0.10 % were determined, respectively. A lower porosity and De for Cl-36 than for H-3 indicates an effect of anion exclusion and the results were found to be in agreement with previous laboratory experiments. However, the comparison to results from a similar in-situ experiment showed that the transport of H-3 and Cl-36 is retarded more in laboratory than in in-situ conditions by matrix diffusion.

Chloride diffusion in pore water in Olkiluoto veined gneiss and pegmatitic granite from a structural perspective

MRS Advances ◽  
2016 ◽  
Vol 1 (61) ◽  
pp. 4047-4052 ◽  
Author(s):  
J. Sammaljärvi ◽  
J. Ikonen ◽  
M. Voutilainen ◽  
P. Kekäläinen ◽  
A. Lindberg ◽  
...  
Keyword(s):  
Elemental Composition ◽  
Pore Water ◽  
Diffusion Coefficients ◽  
Spent Nuclear Fuel ◽  
Chloride Concentration ◽  
Experimental Results ◽  
Chloride Diffusion ◽  
Crystalline Bedrock ◽  
The Matrix ◽  
Pegmatitic Granite

ABSTRACTSpent nuclear fuel from Finnish power plants is planned to be deposited deep in the crystalline bedrock in Olkiluoto, Finland. The bedrock and more specifically the elemental composition of ground water, which is composed of the fracture water and the matrix pore water, needs to be well characterized to assess the risks inherent to the long term safety of the site. To this end, it is valuable to investigate elemental composition of the matrix pore water since it tends to conserve hydrogeological signals for longer time spans compared to open fracture waters.In this study, the chloride concentration of matrix pore water in veined gneiss (VGN) and pegmatitic granite (PGR) samples were investigated. Chloride was out-diffused from the naturally saturated rock cores into deionized water. Chloride pore diffusion coefficients were derived by modelling the chloride breakthrough curves obtained from the out-diffusion experiments. Two component modelling gave best fit to the experimental results. There two diffusion coefficients were (9±2)×10-11 m2/s and (0.5±0.1)×10-11 m2/s for PGR and (2.5±0.5)×10-11 m2/s and (0.4±0.1)×10-11 m2/s for VGN. Porosity distribution and total porosities of the rock samples were studied with the C-14-PMMA autoradiography. Porosity for PGR was found to be 0.6 % with large mineral transecting fissures, and porosity for VGN was found to be 0.7 % with highly porous mineral clusters connected to each other via grain boundaries and intragranular pores. The findings here show that heterogeneity has to be taken into account in modelling to find better agreement with the experimental results. C-14-PMMA autoradiography results indicate dual-component behavior for diffusion in PGR and VGN which were used in the modelling.

The concepts and features of the models of venture investment of energy-oriented startups

2019 ◽  
pp. 74-78
Author(s):  
Oleh Pankiv
Keyword(s):  
Power Plants ◽  
Public Procurement ◽  
Financial Resources ◽  
Managerial Decisions ◽  
Potential Formation ◽  
The Difference ◽  
Alternative Sources ◽  
Methodological Principles ◽  
Profile Characteristics ◽  
Start Ups

The theoretical and methodological principles of promising managerial decisions concerning the efficiency of attracting financial resources, as well as creation of fundamentally new sources of funding for the development of energy-oriented start-ups are considered. The role and place of the sectors of innovative energy saving and alternative sources of power supply in a complex system of energy independence of the country are determined. The way and the main directions of research and development of the ways to solve the aforementioned problem are outlined. As part of the search for optimization solutions, it is suggested to use the principles of the existing statistical and mathematical apparatus, marketing achievements and achievements in network development that take place in gaming business. An analogue comparison of the principal models was carried out, during which the existing types of energy-oriented start-ups were determined and presented. A separate direction in the economic search is proposed, and its profile characteristics are outlined. The type of model is typical for Ukrainian conditions. The author proposed a method of comparing strategies for attracting financial resources into a gaming business in the core of the research. To solve the investigated problem, it is proposed to apply the property of the law of the emergence. The analysis is based on a concrete example of the functioning of the tender procedure, namely the organization of public procurement. The purpose of the article is to consider and analyze the author's proposal to focus on such an important phenomenon as the constant creation of the difference between the expected price and the final contractual price. The model of the solution is based on the systematic combination of this phenomenon and the administrative stimulation of implementation of exclusively energy-innovation projects. The combination of these two points is the basis of an optimization policy for the potential formation and maintenance of a state program to search and stimulate the sources of funding for power plants.

The diffusion of 75Se(IV) in Beishan granite – temperature, oxygen condition and ionic strength effects

2018 ◽  
Vol 107 (1) ◽  
pp. 39-54
Author(s):  
Chunli Wang ◽  
Xiaoyu Yang ◽  
Jiangang He ◽  
Fangxin Wei ◽  
Zhong Zheng ◽  
...  
Keyword(s):  
Ionic Strength ◽  
Effective Diffusion ◽  
Aerobic Condition ◽  
Double Layers ◽  
Solution Viscosity ◽  
Formation Factor ◽  
Experimental Conditions ◽  
Beishan Granite ◽  
Oxygen Condition ◽  
The Difference

Abstract To explore the diffusion behavior of 75Se(IV) in Beishan granite (BsG), the influences of temperature, oxygen condition and ionic strength were investigated using the through-diffusion experimental method. The effective diffusion coefficient De of 75Se(IV) in BsG varied from 4.21×10−14 m2/s to 3.19×10−13 m2/s in our experimental conditions, increased with increasing temperature. The formation factor Ff of BsG was calculated to be nearly constant in the range of temperatures investigated, suggesting that the inner structure of BsG had no significant change in the temperature range of 20–55°C. Meanwhile, the De values of 75Se(IV) in BsG under anaerobic condition was significantly larger than that under aerobic condition, which may be attributed to the difference in the sorption characteristics and species distribution of Se and pH values. Moreover, the diffusion of 75Se(IV) was promoted with ionic strength increased from 0.01 M to 0.1 M, and then decreased at 0.5 M, mainly due to the combined effects of reduced double layers with increased ionic strength and increase of the solution viscosity at higher ionic strength.

scholarly journals Temperature conditions in the RBMK spent fuel pool in the event of disturbances in its cooling mode

2021 ◽  
Vol 7 (1) ◽  
pp. 9-13
Author(s):  
David A. Hakobyan ◽  
Victor I. Slobodchuk
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Spent Nuclear Fuel ◽  
Maximum Temperature ◽  
Spent Fuel ◽  
Cooling Mode ◽  
Temperature Conditions ◽  
Fuel Assemblies ◽  
Spent Fuel Pool

The problems of reprocessing and long-term storage of spent nuclear fuel (SNF) at nuclear power plants with RBMK reactors have not been fully resolved so far. For this reason, nuclear power plants are forced to search for new options for the disposal of spent fuel, which can provide at least temporary SNF storage. One of the possible solutions to this problem is to switch to compacted SNF storage in reactor spent fuel pools (SFPs). As the number of spent fuel assemblies (SFAs) in SFPs increases, a greater amount of heat is released. In addition, no less important is the fact that a place for emergency FA discharging should be provided in SFPs. The paper presents the results of a numerical simulation of the temperature conditions in SFPs both for compacted SNF storage and for emergency FA discharging. Several types of disturbances in normal SFP cooling mode are considered, including partial loss of cooling water and exposure of SFAs. The simulation was performed using the ANSYS CFX software tool. Estimates were made of the time for heating water to the boiling point, as well as the time for heating the cladding of the fuel elements to a temperature of 650 °С. The most critical conditions are observed in the emergency FA discharging compartment. The results obtained make it possible to estimate the time that the personnel have to restore normal cooling mode of the spent fuel pool until the maximum temperature for water and spent fuel assemblies is reached.

scholarly journals Analisis stabilitas tegangan pengisian baterai terhadap putaran kincir angin pada pembangkit listrik tenaga angin

JURNAL ELTEK ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 57
Author(s):  
Mira Esculenta Martawati
Keyword(s):  
Wind Power ◽  
Output Power ◽  
Pitch Angle ◽  
Alternative Energy ◽  
Power Plants ◽  
P Value ◽  
Wind Power Plants ◽  
The Difference ◽  
Market Needs ◽  
Turbine Speed

Pembangkit energi alternatif Saat ini semakin meningkat dikarenakan  berkaitan dengan semakin banyaknya kebutuhan pasar akan energi. Ada beberapa pembangkit energi alternatif yang sudah mulai dibangun antara lain pembangkit listrik tenaga angin. Pada umumnya pembangkit listrik tenaga angin didirikan di daerah pesisir pantai atau di daerah yang  miliki yang menghasilkan banyak angin. Dalam membangun pembangkit listrik tenaga angin dibutuhkan banyak perhitungan yang matang supaya didapatkan desain  yang sesederhana mungkin dengan biaya yang seminim mungkin akan tetapi dapat menghasilkan daya yang maksimal, sehingga dapat mengurangi pemborosan energi dan dapat memanfaatkan tenaga angin yang tersedia pada alam sekitarnya semaksimal mungkin dan dapat dimanfaatkan oleh masyarakat sekitar. Pembuatan simulasi turbin angin dapat dilakukan dengan menggunakan simulasi simulink pada matlab. Hasil dari simulasi dan analisa data adalah terdapat perbedaan  pengaruh antara variasi pitch angle dan kecepatan turbin terhadap daya keluaran dan nilai tegangan , karena nilai  p-value < 0,05 dan membuktikan bahwa H0 dinyatakan ditolak. Hasil dari penelitian ini menunjukkan bahwa semakin besar pitch angle maka kecepatan turbin terhadap daya keluaran dan tegangan yang dihasilkan juga akan semakin besar   Alternative energy generation is increasing as it relates to the growing number of energy market needs. There are several alternative energy plants that have begun to be built, such as wind power plants. In general, wind power plants are established in coastal areas or in areas that have produced a lot of wind. In building wind power plants needed a lot of mature calculations so that the design is as simple as possible with a minimal cost possible but can produce maximum power, so as to reduce energy waste and can utilize the wind power available in the surrounding nature as much as possible and can be utilized by the surrounding community. The manufacture of simulation of wind turbine can be done using simulink simulation in MATLAB. The result of the simulation and data analysis is the difference in influence between the variation of pitch angle and the speed of the turbine to the output power and the voltage value, due to the P-value value of < 0.05 and proving that the H0 declared rejected. The result of this study shows that the greater the pitch angle then the turbine speed to the output power and the resulting voltage will also be greater

scholarly journals Seismic safety evaluation during site selection for the nuclear power plants in Bangladesh

2018 ◽  
Vol 4 (4) ◽  
pp. 251-256 ◽  
Author(s):  
Sergey Shcheklein ◽  
Ismail Hossain ◽  
Mohammad Akbar ◽  
Vladimir Velkin
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Spent Nuclear Fuel ◽  
Heat Removal ◽  
Good Time ◽  
Diagnostics System ◽  
Seismic Impacts

Bangladesh lies in a tectonically active zone. Earlier geological studies show that Bangladesh and its adjoining areas are exposed to a threat of severe earthquakes. Earthquakes may have disastrous consequences for a densely populated country. This dictates the need for a detailed analysis of the situation prior to the construction of nuclear power plant as required by the IAEA standards. This study reveals the correlation between seismic acceleration and potential damage. Procedures are presented for investigating the seismic hazard within the future NPP construction area. It has been shown that the obtained values of the earthquake’s peak ground acceleration are at the level below the design basis earthquake (DBE) level and will not lead to nuclear power plant malfunctions. For the most severe among the recorded and closely located earthquake centers (Madhupur) the intensity of seismic impacts on the nuclear power plant site does not exceed eight points on the MSK-64 scale. The existing predictions as to the possibility of a super-earthquake with magnitude in excess of nine points on the Richter scale to take place on the territory of the country indicate the necessity to develop an additional efficient seismic diagnostics system and to switch nuclear power plants in good time to passive heat removal mode as stipulated by the WWER 3+ design. A conclusion is made that accounting for the predicted seismic impacts in excess of the historically recorded levels should be achieved by the establishment of an additional efficient seismic diagnostics system and by timely switching the nuclear power plants to passive heat removal mode with reliable isolation of the reactor core and spent nuclear fuel pools.

Differences in petrophysical and mechanical properties between low- and middle-rank coal subjected to liquid nitrogen cooling in coalbed methane mining

2021 ◽  
pp. 1-10
Author(s):  
Menglin Du ◽  
Feng Gao ◽  
Chengzheng Cai ◽  
Shanjie Su ◽  
Zekai Wang
Keyword(s):  
Mechanical Properties ◽  
Pore Structure ◽  
Liquid Nitrogen ◽  
Coalbed Methane ◽  
Bituminous Coal ◽  
Thermal Damage ◽  
Physical And Mechanical Properties ◽  
Damage Degree ◽  
Lignite Coal ◽  
The Difference

Abstract Exploring the damage differences between different coal rank coal reservoirs subjected to liquid nitrogen (LN2) cooling is of great significance to the rational development and efficient utilization of coalbed methane. For this purpose, the mechanical properties, acoustic emission (AE) characteristics and energy evolution law of lignite and bituminous coal subjected to LN2 cooling were investigated based on the Brazilian splitting tests. Then, pore structure changes were analyzed to reveal the difference in the microscopic damage between lignite and bituminous coal after LN2 cooling. The results showed that compared with bituminous coal, the pore structure of lignite coal changed more obviously, which was manifested as follows: significant increases in porosity, pore diameters, and pore area; a larger transformation from micropores and transition pores to mesopores and macropores. After LN2 cooling, the thermal damage inside lignite and bituminous coal was 0.412 and 0.069, respectively. The thermal damage reduced the cohesive force between mineral particles, leading to the deterioration of the macroscopic physical and mechanical properties. Simultaneously, denser AE ringing counts and larger accumulated ringing counts were observed after LN2 cooling. Moreover, the random distribution of thermal damage enhanced the randomness of the macrocrack propagation direction, resulting in an increase in the crack path tortuosity. With more initial defects inside coal, a more obvious thermal damage degree and wider damage distribution will be induced by LN2 cooling, leading to more complicated crack formation paths and a higher fragmentation degree, such as that of lignite coal.

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