Environmental and economic assessments of magnetic and inertial fusion energy reactors

Liquids may be used between the magnetic confined fusion plasma and the first wall of the plasma chamber to reduce the material damage through displacements per atom (dpa) and helium gas production. This could extend the lifetime of the first wall in a magnetic fusion energy (MFE) reactor to a plant lifetime of ~30 yr.Neutronic calculations are carried out in S16P3 approximation for a typical HYLIFE-II blanket geometry, an inertial fusion energy (IFE) reactor design. This provides a comparison of the damage data between compressed and uncompressed targets, for IFE and MFE applications, respectively, by using Flibe (Li2BeF4), natural lithium, and Li17Pb83 eutectic as both coolant and wall protection. In the consideration of mainline design criteria, including sufficient tritium breeding ratio (TBR = 1.1), material protection (dpa < 100 and He < 500 parts per million by atom in 30 yr of operation), and shallow burial index, coolant zone thickness values are found to be 60 cm for Flibe, 171 cm for natural lithium, and 158 cm for Li17Pb83 with Type 304 stainless steel (SS-304) as structural material.Material damage investigations are extended to structural materials made of SiC and graphite for the same blanket to obtain waste material suitable for shallow burial after decommissioning of the power plant.The dpa values and helium production rates in graphite are comparable to those in SS-304. However, they are higher in SiC than in SS-304 and graphite.The average neutron heating density in the external 1.6-mm-thick SS-304 shell of the investigated blanket beyond the SiO2 insulation foam decreases rapidly with increasing thickness of the Flibe coolant. With DR = 60 and 80 cm, it becomes only 594 and 95 μW/cm3, respectively. The design limit for heat generation density in superconducting coils for magnetic fusion is 80 μW/cm3. A very important result of this work is that a blanket with liquid-curtain protection would not require extra shielding for superconducting coils around the fusion plasma chamber. This could result in an important simplification of the design.

An economical and environment-friendly fusion reactor system is needed for the realization of attractive power plants. Comparative system studies have been done for magnetic fusion energy (MFE) reactors, and been extended to include inertial fusion energy (IFE) reactors by Physics Engineering Cost (PEC) system code. In this study, we have evaluated both tokamak reactor (TR) and IFE reactor (IR). We clarify new scaling formulas for cost of electricity (COE) and CO2 emission rate with respect to key design parameters. By the scaling formulas, it is clarified that the plant availability and operation year dependences are especially dominant for COE. On the other hand, the parameter dependences of CO2 emission rate is rather weak than that of COE. This is because CO2 emission percentage from manufacturing the fusion island is lower than COE percentage from that. Furthermore, the parameters dependences for IR are rather weak than those for TR. Because the CO2 emission rate from manufacturing the laser system to be exchanged is very large in comparison with CO2 emission rate from TR blanket exchanges.

Structural materials for laser-based inertial fusion energy (IFE) reactor concepts are expected to operate under pulsed irradiation conditions, with cycles consisting of microsecond-long neutron bursts followed by inter-pulse periods of up to one second in duration. During each laser shot, irradiation damage is introduced at dose rates that are up to six orders of magnitude higher than those in their magnetic fusion energy (MFE) counterparts. Under certain conditions, the inter-pulse periods may last an amount of time sufficient to anneal much of the damage introduced during each shot. This phenomenon is highly temperature dependent, with pulsed heating directly linked to the pulsed damage, large surface temperature spikes may also occur. As such, this intermittent mode of operation has the potential to lead to fundamental differences in how irradiation damage accumulates in structural reactor materials. However, damage to structural materials under IFE conditions has received comparatively much less attention than in MFE, as pulsed conditions add yet an extra dimension to the already extremely challenging problem of microstructural evolution under fusion neutron irradiation in structural materials. In this work we use the stochastic cluster dynamics (SCD) method to simulate the evolution with time of defect cluster concentrations under IFE conditions. We consider the Laser Inertial Fusion Energy (LIFE) reactor concept as the representative IFE design for our study, for which detailed spectral information is available, including gas transmutant production. We simulate several pulse frequencies and three different temperatures, and compare the results with continuous irradiation cases under identical average dose rates. The simulations are run in Fe-9Cr system as a model alloy for reduced-activation ferritic/martensitic (RAFM) steels, which are the leading structural material candidates for first-wall structures in MFE and IFE devices. We find that, in practically all scenarios, pulsed irradiation restricts the formation of helium-vacancy clusters relative to the levels seen under equivalent steady irradiation conditions. As well, although self-interstitial atom clusters do accumulate under pulsed operation, their number densities remain up to an order of magnitude lower than in continuous irradiation conditions. Based on the SCD results, we provide a temperature-pulse rate map to identify regions where pulsed irradiation may lead to larger defect accumulation than under continuous irradiation.

Accidental release characteristics of activated materials in inertial and magnetic fusion reactors

Controlled fusion energy is one of the long term, non-fossil energy sources available to mankind. It has the potential of significant advantages over fission nuclear power in that the consequences of severe accidents are predicted to be less and the radioactive waste burden is calculated to be smaller. Fusion can be an important ingredient in the future world energy mix and can be part of an ‘insurance policy’ energy strategy to develop new sources as a hedge against environmental, supply or political difficulties connected with the use of fossil fuel and present-day nuclear power. Progress in fusion reactor technology and design is described for both magnetic and inertial fusion energy systems. The projected economic prospects show that fusion will be capital intensive, and the historical trend is towards greater mass utilization efficiency and more competitive costs. Recent studies emphasizing safety and environmental advantages show that the competitive potential of fusion can be further enhanced by specific choices of materials and design. The safety and environmental prospects of fusion appear to exceed substantially those of advanced fission and coal. For example, the level of radioactivity in a low activation fusion reactor at 1 year and at 100 years after shutdown is calculated to be about one-millionth of the radioactivity in a fission reactor of the same power. Likewise, the maximum plausible dose predicted at the site boundary in the case of a low activation fusion reactor is estimated to be between 100 and 500 times smaller than that estimated for a fission power plant. Clearly, a significant and directed technology effort is necessary to achieve these advantages. Typical parameters have been established for magnetic fusion energy reactors, and a tokamak at moderately high magnetic field (about 7 T on axis) in the first regime of MHD stability (β ≤ 3.5 I/aB) is closest to present experimental achievement. Further improvements of the economic and technological performance of the tokamak are possible through the following achievements: higher magnetic fields to lower the required plasma current and reactor size; higher values of the plasma beta, including reaching the second stable MHD regime, to lower the requirements on field and plasma current; and more efficient techniques to drive the plasma current. In addition, alternative, non-tokamak magnetic fusion approaches may offer substantive economic and operational benefits, although at present these concepts must be projected from a less developed physics base. For inertial fusion energy, reactor studies are at an earlier stage, but the essential requirements are a high efficiency (≥ 10%) repetitively pulsed pellet driver capable of delivering up to 10 MJ of energy on target, targets capable of an energy gain (ratio of energy produced to energy on target) of about 100, reactor chambers capable of absorbing the energy released per shot at conditions consistent with power generation, and effective means of isolating the target chamber and driver system.

Potential use of molten salts bearing plutonium fluorides in a magnetic fusion energy reactor

Results from systematic modeling of neutron damage in inertial fusion energy reactors

The flow of residual metal vapor in an inertial fusion energy (IFE) reactor chamber causes (a) forced convection heat transport to the target, (b) drag force to the target, and (c) deviation of the orbit of the target. To solve these difficulties, a flying metal pipe concept for target transport in an IFE reactor is proposed.The metal pipe is composed of material identical to the liquid metal used in the IFE reactor. The metal pipe (typically 0.5-cm radius and 2-m length) is injected from the top of the IFE reactor chamber. Subsequently, the IFE target is injected, and it goes into the metal pipe, goes out from the other side of the pipe, and arrives at the center of the IFE reactor chamber to be shot by energy beams. The target in the pipe is protected against radiation, forced convection heat from residual gas, and the wind in the IFE reactor chamber. In the case that the flying metal pipe is used in the reactor, heat transport to the target and deviation of the orbit of the target decrease. After microexplosion of the IFE target, the metal pipe arrives at the bottom of the reactor chamber and melts in the liquid-metal pool.

As for electric power generation on land, the wind energy conversion system is widely used because of its environmental problems. For the marine environment, some methods to reduce air pollution such as CO2, NOx, and SOx from diesel engines of ships have been discussed recently.In this paper, a study on the application of the wind energy conversion for the electric power generation system of a large ship was carried out.At first, the paper considered and proposed the design procedure of the introduction of the wind energy conversion system to ships. Secondly, a case study was carried out on the wind energy generation system to a coal cargo ship using the proposed design. Finally, in order to evaluate the application of the wind energy conversion system, the fuel consumption and NOx and SOx emission were compared with those of the conventional electric power generation system consisting of diesel engine generator. The electric power generation system could reduce the fuel consumption and NOx and SOx emission from the ship. The application of the wind energy conversion system to the electric power generating system of ship is worth discussing to solve the marine environmental problems.

Emissions of greenhouse gases (GHGs) from animal feeding operations to the atmosphere are of environmental importance and concerns because of their impact on global warming. Gaseous concentrations and emission rates (ERs) of animal facilities can be affected by the animal production stages, animal species, dietary nutrition, housing types, manure handling schemes, and environmental conditions. This article reports ERs of methane (CH4), nitrous oxide (N2O), and carbon dioxide (CO2) for a typical, naturally ventilated 24-crate swine farrowing barn located in suburban Beijing, China, that was monitored over one-year period. The measurements were made at bi-monthly intervals (i.e., six measurement episodes total), with each measurement episode covering three consecutive days. Gaseous concentrations were monitored at bi-hourly intervals throughout each 3-day measurement episode. The ventilation rate of the barn was estimated using the CO2 mass balance method. The GHG concentrations and ERs of the farrowing barn showed diurnal and seasonal variations. Specifically, the concentrations (monthly mean ±SD, mg m-3) ranged from 2.3 (±0.3) to 9.3 (±2) for CH4, from 0.6 (±0.02) to 1.2 (±0.16) for N2O, and from 1,370 (±163) to 11,100 (±950) for CO2, with the higher levels occurring in January and the lower levels in July. The specific ER ranged from 95.2 to 261.8 mg h-1 pig-1 for CH4, from 6.4 to 12.9 mg h-1 pig-1 for N2O, and from 122.9 to 127.3 g h-1 pig-1 for CO2. On the basis of per animal unit (1 AU = 500 kg live body mass), the average daily ERs of the farrowing barn were 9.6 ±3.6 g AU-1 d-1 for CH4, 0.54 ±0.15 g AU-1 d-1 for N2O, and 7.5±0.1 kg AU-1 d-1 for CO2. Results of the GHG ERs from this study differ markedly from the limited literature data collected primarily under European production systems and conditions. Results of the current study provide some baseline data on GHG ERs for swine farrowing operations, thus contributing to development or improvement of GHG emission inventory under the Chinese livestock production conditions.

Greenhouse gas (GHG) emissions are an important factor in the evaluation of green industrial growth, when low GHG emissions along with high industrial growth are expected. In this paper, the improvement of sustainable development of industry in China (2007–2015) was investigated via analysis of the relationships between the GHG emissions and energy consumption in comparison to European countries. A hierarchical cluster analysis (HCA) was conducted to distinguish industrial growth with GHG emission and energy consumption structures. The results of this research indicated that green industrial growth in Europe had a negative annual rate of GHG emissions. This contributed to the ratio of renewable energy consumption increasing to a maximum of 33% and an average of 16%. In comparison, the GHG emissions in China increased at a rate of 50% to 77% in the main industrial provinces since 2007 with their rapid industrial growth. The rate of GHG emissions decreased after 2012, which was 7% or less than the rate of emissions in the industrial provinces. Contrary to in Europe, the decreasing rate of GHG emissions in China was attributed to the improvement of fossil energy efficiency, as renewable energy consumption was less than 10% in most industrial provinces. Our data analysis identified that the two different energy consumption strategies improved green industrial growth in Europe and China, respectively. Our data analysis identified the two different energy consumption strategies employed by Europe and China, each of which promoted green industrial growth in the corresponding areas. We concluded that China achieved green industrial growth through an increase in energy efficiency through technology updates to decrease GHG emissions, which we call the “China Model.” The “Europe Model” proved to be quite different, having the core characteristic of increasing renewable energy use.

The plasma–material interaction and high heat flux properties of beryllium are reviewed to determine its suitability as a plasma‐facing component in magnetic fusion energy reactors. Consideration is given to beryllium’s outgassing, erosion, and hydrogen retention characteristics. Its responses to normal and off‐normal high heat fluxes are compared to graphite in both the as‐received and the neutron‐irradiated states. Beryllium’s performance in present‐day devices is assessed, and its expected behavior in future reactors is summarized. It is concluded that beryllium is potentially a better plasma‐facing material than graphite and that more development and testing is warranted.

APPLICATIONS OF SOLID STATE TRACK RECORDERS IN UNITED STATES NUCLEAR REACTOR ENERGY PROGRAMS

Studies of turbulent liquid sheets for protecting IFE reactor chamber first walls

This paper studies the effect on the rate of growth of carbon dioxide emission in seaports’ atmosphere of replacing a part of the fossil fuel electrical power generation by clean renewable electrical energies, through two different scheduling strategies. The increased rate of harmful greenhouse gas emissions due to conventional electrical power generation severely affects the whole global atmosphere. Carbon dioxide and other greenhouse gases emissions are responsible for a significant share of global warming. Developing countries participate in this environmental distortion to a great percentage. Two different suggested strategies for renewable electrical energy scheduling are discussed in this paper, to attain a sustainable green port by the utilization of two mutual sequential clean renewable energies, which are biomass and photovoltaic (PV) energy. The first strategy, which is called the eco-availability mode, is a simple method. It is based on operating the renewable electrical energy sources during the available time of operation, taking into consideration the simple and basic technical issues only, without considering the sophisticated technical and economical models. The available operation time is determined by the environmental condition. This strategy is addressed to result on the maximum available Biomass and PV energy generation based on the least environmental and technical conditions (panel efficiency, minimum average daily sunshine hours per month, minimum average solar insolation per month). The second strategy, which is called the Intelligent Scheduling (IS) mode, relies on an intelligent Reconfigured Whale Optimization Technique (RWOT) based-model. In this strategy, some additional technical and economical issues are considered. The studied renewable electrical energy generation system is considered in two scenarios, which are with and without storage units. The objective (cost) function of the scheduling optimization problem, for both scenarios, are developed. Also, the boundary conditions and problem constraints are concluded. The RWOT algorithm is an updated Whale Optimization Algorithm (WOA). It is developed to accelerate the rate of reaching the optimal solution for the IS problem. The two strategies simulation and implementation are illustrated and applied to the seaport of Damietta, which is an Egyptian port, located 10 km to the west of the Nile River (Damietta Branch). The scheduling of PV and biomass energy generation during the different year months is examined for both strategies. The impact of renewable electrical energies generation scheduling on carbon dioxide emission and consequently global warming is discussed. The saving in carbon dioxide emission is calculated and the efficient results of the suggested models are clarified. The carbon dioxide emission is reduced to around its fifth value, during renewable energy operation. This work focuses on decreasing the rate of growth of carbon dioxide emission coming from fossil fuel electrical power generation in Egypt, targeting, sustainable green seaports, through three main contributions in clean renewable electrical energies scheduling,. The contributions are; 1-presenting the eco-availability mode for minimum gifted biomass and PV energy generation, 2-developing and progressing the IRWOT scheduling strategy for both scenarios (with and without storage unit), 3-defining the scheduling optimization problem boundary conditions and constraints.