Estimates of SO2, NOx, and Solid Particles Emissions into the Atmosphere as a Result of Burning of Natural Gas and Coal by Heating and Electric Power Plants

The specific atmospheric emissions of SO₂, NO _x , and solid particles along the complete technological chains of motion of natural gas and Kuznetskii and Kansko-Achinskii coal from gas and coal deposits to burning by heating and power plants are calculated. The atmospheric emissions fractions for SO₂, NO _x , and solid particles directly from heating and power plants are 94–99%. The atmospheric emissions of SO₂, NO _x , and solid particles in the complete fuel cycles for production of electricity in Russia and Germany are compared.     

Layout of an internally heated gas generator for the steam gasification of coal

Industrial-scale steam gasification of coal using heat from high temperature reactors requires research and development on allothermal gas generators. Bergbau-Forschung GmbH, Essen, does theoretical and experimental work in this field. The experiments deal with reaction kinetics, heat transfer and material tests. Their significance for the layout of a full-scale gas generator is shown. Including material specifications, the feasibility of a gasifier, characterized by a fluid bed volume of 318 m³ and a heat transferring area of 4000 m², results. The data, now available, are used to determine the gasification throughput from the heat balance, i.e. the equality of heat consumed and heat transferred. Throughputs of about 50 t/hr of coal are possible for a single gas generator, the helium outlet temperature of the HTR being 950°C. Bergbau-Forschung has commissioned a medium-scale pilot plant (200 kg/hr).     

Methane from synthesis gas and operation of high-temperature methanation

The methanation process is an important unit in generating substitute natural gas (SNG) from coal and in providing heat in the Long-Distance Nuclear Energy Transport (NFE) system. Procedures for methanizing synthesis gases containing CO, CO₂ and H₂ have been developed and tested at the Kernforschungsanlage Jülich GmbH (KFA - Federal Republic of Germany) since 1976. This is being carried out together with the partner in the NFE Project, Rheinische Braunkohlenwerke AG, Cologne (FRG).It has been demonstrated in several thousand operating hours at the KFA since 1979 that the procedures and components developed, as well as the catalysts employed satisfy the demands made by high-temperature methanation in the three-stage methanation plants ADAM I and ADAM II with a SNG gas production of 200 or 3300 m³ (STP)h⁻¹ and a useful heat capacity of 300 kJ/s or 5.8 MJ/s.In 1981 a single-stage pilot plant was put into operation at the KFA in which one reactor with cooled stepped reaction tubes and catalytic fixed beds was utilized. The test operation of 1100 hours shows that at a high gas load on the reaction tubes, thermodynamic equilibrium with a high methane content in the product gas can be achieved with simultaneous steam production at 100 bar.     

Development of water leak detection method in fusion reactors using water-soluble gas

A water leak detection method using krypton (Kr) as a water-soluble tracer has been proposed for fusion reactors with fully circulating the in-vessel cooling water. This method was targeted for applying to the International Thermonuclear Experimental Reactor (ITER), and the 10⁻³ Pa m³/s order of water leak valves were fabricated and connected to the water loop circuit. The water leaks were effused into the vacuum vessel evacuated by a cryopump and the water dissolved Kr was detected by a quadrupole mass spectrometer (QMS). When two leak valves with 1 m distance were attached to the test pipe with 30 °C heating, two distinct, the mass to charge number ratio (m/e) of 84 peak current rises caused by the water leak were successfully detected with the time interval of 39 s. On the other hand, the water accession length as a function of the traveling time was calculated by considering a natural convection flow caused by the 30 °C heating, where the traveling time was 44.6 s for the 1 m length. This means that the observed positional accuracy is 12.6%, based on the calculation. To enhance the positional accuracy, the detailed flow simulation is indispensable. This method can be applied to the ITER condition.     

Optimization of the radiation shielding mass for the magnet coils of the VISTA spacecraft

An attempt has been made for the optimisation of the radiation shielding of a spacecraft design concept with inertial fusion energy propulsion for manned or heavy cargo deep space missions beyond earth orbit. Rocket propulsion is provided by fusion power deposited in the inertial confined fuel pellet debris, and with the help of a magnetic nozzle. The allowable nuclear heating in the super conducting magnet coils (up to 5 mW/cm³) is the crucial criterion for the dimensioning of the radiation shielding structure of the spacecraft. The optimized design reduced the shield mass from 600 tons to 93 and 88 tons with natural and enriched lithium, respectively. The space craft mass was 6000 tons. Total peak nuclear power density in the coils is calculated to be 5.0 mW/cm³ for a fusion power of 17,500 MW. Peak neutron heating density is 2.6 mW/cm³ and peak γ-ray heating density is 2.9 mW/cm³ (all on different points). However, volume averaged heat generation in the coils is much lower, namely 0.30, 0.73 and 1.03 mW/cm³ for neutron, γ-ray and total nuclear heating, respectively.     

Economic, Environmental, and Job Impacts of Increased Efficiency in Existing Coal-Fired Power Plants

Analyses of the CO₂ mitigation potential of increasing the efficiency of existing U.S. coal-fired power plants have indicated that significant CO₂ emissions could be avoided if the efficiency of existing plants could be improved. This paper expands the analysis and estimates the potential economic and employment impacts of engaging in an U.S.-wide efficiency improvement program. Specifically, this study: (1) Discusses the factors affecting the operating efficiency of coal-fired power plants; (2) Identifies feasible efficiency improvements to existing coal-fired power plants; (3) Estimates the costs of coal power plant efficiency improvements; (4) Estimates the costs of a widespread coal power plant efficiency improvement (CPPEI) program; (5) Assesses the potential impacts of the CPPEI program, including the annual jobs created by the CPPEI program, the permanent operations and maintenance (O&M) jobs created by the CPPEI program, and the potential occupational impacts; (6) Evaluates the advantages and disadvantages of two CPPEI program options; and (7) Discusses the broader economic and employment implications of the program.     

哈尔滨燃煤电厂周围土壤放射性水平的分析

煤炭燃烧过程中,放射性核素会不同程度的在飞灰和炉渣中富集,进而随着飞灰和炉渣进入土壤环境中,对土壤造成不同程度的放射性污染。本文以哈尔滨群力燃煤电厂和呼兰燃煤电厂为研究对象,在距电厂1 km范围内布设采样点,每个采样点土壤分3层采样,即A层深度:0～10 cm,B层深度:10～20 cm,C层深度:20～30 cm。利用高纯锗γ谱仪测量土样中的天然放射性核素,分析了燃煤电厂周围土壤样品中²³⁸U、²³²Th、²²⁶Ra、⁴⁰K的含量,并与黑龙江省土壤天然放射性核素测量结果进行了比较。结果表明,在群力电厂和呼兰电厂1 km范围内周围土壤中,除了天然放射性核素²³⁸U以外,其他3种核素含量都未超出全省含量最大值,其中核素²³²Th的含量甚至低于全省大部分地区;燃煤电厂的长期运行给土壤环境带来了一定的放射性影响,土壤本底的放射性核素含量发生了一些变化,这种变化在呼兰电厂周围的土壤中表现得更为明显,但是并未超出国家规定的标准,污染程度在可接受的范围内。     

Behavior of Radioactive Iodine Isotopes in the Multiple Forced Circulation Loop in an RBMK Reactor

The flow of iodine, including ¹³¹I, into the coolant water in a nuclear power plant with an RBMK-1000 reactor under normal operating conditions and during transient regimes is analyzed. It is shown that under normal operating conditions the specific activity of ¹³¹I in the coolant is correlated with the iron concentration. During shutdown, its content increases by factors of 30–200. The emission of ¹³¹I into the coolant can be decreased by factors of 10–15 and the degree of unsealing of fuel elements can be decreased if before shutdown the reactor is held for 2–5 days at 50% of the nominal power level. Recommendations are made for decreasing ¹³¹I emissions into the atmosphere. The adoption of these recommendations at the Leningrad nuclear power plant has reduced the ¹³¹I emissions into the atomsphere by a factor of 17. __________ Translated from Atomnaya Energiya, Vol. 99, No. 2, pp. 103–108, August 2005.     

Current and Future Problems of the Fuel Supply for Nuclear Power

The structure of the nuclear fuel cycle, consisting of the technological stages of uranium production, refining, enrichment, fabrication of nuclear fuel, and reprocessing of the spent fuel for reuse of the fissioning materials, is examined. Supplying fuel includes supplying fuel for Russian nuclear power plants, propulsion and research reactors, export of fuel for nuclear power plants and research reactors constructed according to Russian designs, export of low-enriched uranium and fuel for nuclear power plants constructed according to foreign designs. The explored deposits of natural uranium, the estimated stores of uranium in reserve deposits, and warehoused stores will provide nuclear power with uranium up to 2030 and in more distant future with the planned rates of development. The transition of nuclear power plants to a new fuel run will save up to 20% of the natural uranium. The volume of reprocessing of spent fuel and reuse of ²³⁵U makes it possible to satisfy up to 30% of the demand for resources required for Russian nuclear power plants. The most efficient measure of the resource safety of Russian nuclear power is implementation of an interconnected strategy at each stage of the nuclear fuel cycle.     

High pressure corium melt quenching tests in FARO

First-of-a-kind experimental data on the quenching of large masses of corium melt of realistic composition when poured into pressurised water at reactor scale depths are presented and discussed. The tests involved 18 and 44 kg of a molten mixture 80 w% UO₂-20 w% ZrO₂, which were delivered by gravity through a nozzle of diameter 0.1 m to 1 m depth nearly saturated water at 5.0 MPa. The objective was to gain early information on the melt/water quench process previous to tests that will involve larger masses of melt (1.50 kg of mixtures UO₂---ZrO₂---Zr). Particularly, pressures and temperatures were measured both in the gas phase and in the water. The results show that significant quenching occurred during the melt fall stage with 30% to 42% of the melt energy transferred to the water. About two-thirds of the melt broke up into particles of mean size of the order of 4.0 mm. The remaining one-third collected still molten in the debris catcher but did not produce any damage to the bottom plate. The maximum downward heat flux was 0.8 MW m². The maximum vessel overpressurisation, i.e. 1.8 MPa, was recorded with 44 kg of melt poured into 255 kg of water and a gas phase volume of 0.875 m³. No steam explosions occurred.     

用公众健康危害指标对我国燃煤电厂气载释放物的环境危害评价

本文在详细调查我国燃煤电厂除尘器类型及除尘效率等基本状况的基础上，利用公众健康危害评价方法评价了我国燃煤电厂载释放的非放化学污染物和放射性物质所致的公众健康危害。计算结果表明我国燃煤电厂载释放物的危害主要是由其非放化学污染物产生的。     

Results from the operation of a semi-technical test plant for brown coal hydrogasification

The Rheinische Braunkohlenwerke AG has built and has been operating a semi-technical pilot plant for hydrogasification of coal in fluidized bed. The objective is to develop a coal gasification process with hydrogen for producing directly substitute natural gas. Between 1976 and 1982, the semi-technical pilot plant was operated for about 27000 h under test conditions, more than 12000 h of which were under gasification conditions. During this time, approximately 1800 metric tons of dry coal were gasified. The longest coherent operational phase under gasification conditions was 748 h in which 86.4 metric tons of dry lignite were gasified. Carbon gasification rates up to 82% and methane contents in the dry raw gas (free of N₂) up to 48 vol% were obtained. A detailed evaluation of the test results provided extensive information on the influence of operational parameters on the efficiency dates of the gasifier. Moreover, several components were tested for which no operational experience had previously been gained; these were newly developed devices, e.g. the inclined tube for feeding coal into the fluidized bed. Within the framework of scale-up to large-scale coal gasification plants, a pilot plant having a capacity of about 10 metric tons of dry brown coal per hour was commissioned in late 1982. On May 30, 1983, coal was for the first time fed into the plant. The present test planning provides for tests with brown coal till the end of 1985. This could be followed by the use of other coals, such as hard coal.     

Roles of nuclear energy in Japan''s future energy systems

The roles of nuclear energy in Japan's future energy systems were analyzed from the viewpoint of securing stable energy supply and reducing carbon dioxide (CO₂) emissions. The MARKAL model, developed in the Energy Technology Systems Analysis Programme (ETSAP) of the IEA, was used for establishing several energy scenarios with different assumptions on the availability of nuclear energy, natural gas, and a CO₂ disposal option. Nuclear energy was assumed to apply for synthetic fuel production as well as for conventional electric power generation. By comparing the CO₂ emission and system costs between these energy scenarios, following results were obtained. Without nuclear energy, the CO₂ emissions will hardly be reduced because of substantial increases in coal utilization. CO₂ disposal will be effective in reducing the emissions, however at much higher costs than the case with nuclear energy. The expansion of natural gas imports, if alone, will not reduce the emissions at enough low levels.     

中国燃煤发电排放的放射性环境影响评价研究

选取不同装机容量等级的典型燃煤机组作为研究对象,按照不同地理区域划分滨海北方、滨海南方、内陆北方、内陆南方等4个评价区,采用一批新的调查数据和参数,评价当前我国燃煤发电排放的放射性环境影响。结果表明:(1)全国燃煤电厂放射性排放所致80 km范围公众的归一化集体剂量平均值为2.2人·Sv/GWa。(2)小火电机组所致剂量约为6.0人·Sv/GWa,主流燃煤机组约为1.8人·Sv/GWa,小火电机组是主流燃煤机组的约3倍。(3)剂量贡献最大的核素是²¹⁰Po,其次是²¹⁰Pb。食入和吸入内照射是主要照射途径。(4)不同燃煤电厂周围的人口密度差别很大,使得集体剂量相差可达1个数量级。基本结论:与天然辐射源所致公众照射剂量相比,燃煤发电的辐射环境影响仍然很小;煤电的辐射环境影响是核电的34倍。淘汰小火电机组、实施超低排放改造,我国燃煤发电所致公众归一化集体剂量仍有进一步降低的空间。目前电厂除尘技术难以高效去除和有效控制²¹⁰Po排放,有必要进一步研究。     

Design and experience of HEU and LEU fuel for WWR-M reactors

Thin-walled WWR-M5 fuel elements were designed and manufactured and have been used successfully for 16 years; they contain twice as much uranium-235 as the WWR-M2 and WWR-M3 fuel elements. The fuel elements have been optimized with regard to their neutron physics and thermal-hydraulic parameters and fuel consumption has been minimized. The mean specific power in the core of the WWR-M reactor was raised to 230 kW l⁻¹, the measured maximum volume thermal specific power was 900±100 kW l⁻¹ and the surface specific power was 136±15 W cm⁻². The WWR-M5 fuel elements enable the power of the WWR-M pooltype reactor to be raised to 30 MW while simultaneously increasing the number of cells in the core available for experimentation by a factor of approximately two and reducing fuel element consumption. Reactor tests of WWR-M fuel elements with reduced fuel enrichment (36 and 21%) were carried out for a meat uranium density up to 2–3 g cm⁻³. Conversion of WWR-SM-type reactors to these fuel elements did not lead to a loss in reactivity and enabled their power to be increased to 20–30 MW.     

低功率条件下低高度差开式自然循环流动模式研究

开式自然循环系统广泛应用于能源和化工领域。在一些特殊条件下，低高度差自然循环系统应运而生，但目前研究并不充分。本文采用蒸汽加热方式，对这类的低高度差开式自然循环系统在低功率水平下的流动模式进行了实验研究，并对其流动模式以及存在物理现象进行了详细的分析。研究发现，在不同功率水平下，因受不凝性气体和过冷沸腾的影响，该自然循环系统主要存在4种流动模式。最后，对不同流动模式转变点的加热段进出口温度进行分析，结果表明加热段出口温度可作为系统流动模式的判定依据。      

The costs of generating electricity and the competitiveness of nuclear power

This paper provides an analysis on the costs of generating electricity from nuclear and fossil sources (coal and natural gas) based on the most recent technical data available in literature. The aim is to discuss the competitiveness of nuclear power in a liberalized market context by considering the impact on the generating costs of the main factors affecting the viability of the nuclear option. Particular attention will be devoted to study the variability of the generating costs regarding the level of risk perceived by investors through a sensitivity analysis of the generating costs with respect to the cost of capital and the debt fraction of initial investment. The impact of environment policies is also considered by including a “tax” on carbon emissions. The analysis reveals that nuclear power could have ample potentiality also in a competitive market, particularly if the level of risk perceived by the investors keeps standing low. For low values of the cost of capital, nuclear power seems to be the most viable solution. Uncertainty about environmental policies and unpredictability of carbon emissions costs might offer further margins of competitiveness.     

Global transportation scenarios in the multi-regional EFDA-TIMES energy model

The aim of this study is to assess the potential impact of the transportation sector on the role of fusion power in the energy system of the 21st century. Key indicators in this context are global passenger and freight transportation activities, consumption levels of fuels used for transportation purposes, the electricity generation mix and greenhouse gas emissions. These quantities are calculated by means of the global multi-regional EFDA-TIMES energy system model. For the present study a new transportation module has been linked to the EFDA-TIMES framework in order to arrive at a consistent projection of future transportation demands. Results are discussed implying various global energy scenarios including assumed crossovers of road transportation activities towards hydrogen or electricity infrastructures and atmospheric CO₂ concentration stabilization levels at 550 ppm and 450 ppm. Our results show that the penetration of fusion power plants is only slightly sensitive to transportation fuel choices but depends strongly on assumed climate policies. In the most stringent case considered here the contribution of electricity produced by fusion power plants can become as large as about 50% at the end of the 21st century. This statement, however, is still of preliminary nature as the EFDA-TIMES project has not yet reached a final status.     

Production cross-sections of residual radionuclides from proton-induced reactions on Ag up to 40 MeV

We measured the cross-sections of the ^{104g,105,106m}Ag and ^104,107Cd radionuclides produced by proton-induced reactions on natural silver by using a stacked-foil activation technique in the energy range from a threshold energy to 40 MeV at a MC50 cyclotron. The results showed generally good agreement with available data as well as the theoretical data. The integral yields for thick targets were also deduced using the measured cross-sections and the stopping power of ^natAg over the energy range from a threshold energy to 40 MeV, taking into account that the total energy is absorbed in the targets. The production cross-sections for the ^104gAg and the ¹⁰⁴Cd radionuclides from natural silver were measured for the first time.