Investigation of hydrogen production potential of the LASER inertial confinement fusion fission energy (LIFE) engine

The main purpose of this paper is to research of the time-dependent hydrogen production possibility of the Laser Inertial Confinement Fusion Fission Energy (LIFE) engine using steam methane reforming (SMR), sulfur–iodine (S–I) thermochemical water splitting and high temperature electrolysis (HTE) cycles. The fuel zone of the LIFE engine contains 90 vol% Flibe coolant and 10 vol% TRISO coated minor actinides. Firstly, to examine the time-dependent hydrogen generation potential of this reactor, the time-dependent neutronic performance of the reactor has been performed with using the MCNP neutron transport code. As a result of neutronic calculations, tritium production (TBR), energy multiplication factor (M) and fuel burnup (BU) values have been computed. Secondly, the total power required for SMR, S–I and HTE cycle process have been calculated by using the time dependent energy multiplication factor obtained from the neutronic results. Depending on this total power, the change of hydrogen production with operation time in the LIFE engine has been investigated. As a result of the calculations, it has been found that the LIFE engine has a good both neutronic performance and hydrogen production by SMR, S–I and HTE cycle process.     

Evaluation and comparison of hydrogen production potential of the LIFE fusion reactor by using copper–chlorine (Cu–Cl), cobalt–chlorine (Co–Cl) and sulfur–iodine (S–I) cycles

In this paper, the hydrogen production and neutronic analysis of the Laser Inertial Confinement Fusion-Fission Engine (LIFE) fusion reactor have been analyzed. The potential of hydrogen production from unit integrated of the reactor with three different hydrogen production methods which has copper-chlorine (Cu–Cl) cycle, cobalt-chlorine (Co–Cl) cycle and sulfur-iodine (S–I) cycle have been investigated. Neutronic performance analysis for various parameters was calculated statically by using Monte Carlo N-Particle Nuclear Code and determined optimum reactor operation conditions. The hydrogen production potential for all conditions was investigated as statically. And also, the production potential with determining optimum conditions was performed over operation plant. Tristructural isotropic (TRISO) coated thorium carbide (ThC) was used as fuel of LIFE fusion reactor. Natural lithium and FLiNaBe (LiF + NaF + BeF₂) were used first and second coolant, respectively. In the statistical analysis, effects of ThC fuel ratio, 1st and 2nd coolant zone thicknesses were examined. As a consequence of the neutronic analysis, tritium breeding values and energy multiplication values (M) was attained and according to M values, hydrogen production amount, required thermal power and thermal power ratios were acquired. Among the used hydrogen production methods, Cu–Cl cycle produced the highest hydrogen amount, while the Co–Cl cycle has the lowest H₂ amount. At the end of the reactor operation time for determining optimum conditions, the produced hydrogen amounts are 9.00, 4.80 and 7.36 kg/s for Cu–Cl, Co–Cl and S–I cycles, respectively.     

Neutronic analysis of denaturing plutonium in a thorium fusion breeder and power flattening

The purpose of this study is to denature nuclear weapon grade quality plutonium in a thorium fusion breeder. Ten fuel rods containing the mixture of ThO₂ and PuO₂ are placed in a radial direction in the fissile zone where ThO₂ is mixed with variable amounts of PuO₂ to obtain a quasi-constant nuclear heat production density. The plutonium composition volume fractions in the fuel rods are gradually increased from 0.1% to 1% by 0.1% increments. The fissile fuel zone is cooled with four various coolants with a volume fraction ratio of 1 (V_coolant/V_fuel = 1). These coolants are helium gas, flibe “Li₂BeF₄”, natural lithium and eutectic lithium “Li₁₇Pb₈₃”. Nuclear weapon grade quality ²³⁹Pu in the fuel composition is denatured due to the accumulation of the ²⁴⁰Pu isotope in the fissile zone after 18 months of plant operations. Under a first wall fusion neutron current load of 2.222 × 10¹⁴ (14.1 MeV n/cm² s), which corresponds to 5 MW/m², by a plant factor of 100%, at the end of the plant operation, the fissile fuel enrichment quality between 6.0% and 10% is obtained depending on the coolant types. During the plant operation, the tritium breeding ratio (TBR) should be at least 1.05. In the selected blanket, only the flibe coolant is already self sustaining at start up. The TBR increases steadily due to the higher neutron multiplication rate during the plant operation period. The highest TBR is obtained for the eutectic lithium coolant 1.4035, followed by the flibe coolant 1.3095, helium gas coolant 1.2172 and natural lithium coolant 1.0553 at the end of the operation period of 48 months. The energy multiplication factor M changed between 2.1731 and 6.6241 depending on coolant type during the operation period. The peak to average fission power density ratio Γ in the blanket decreases by ∼15%, which allows a more uniform power generation in the fissile zone. The isotopic percentage of ²⁴⁰Pu reaches higher than 5% in all coolant types. This is very important for international safety.     

Hydrogen production via steam-methane reforming in a SOMBRERO fusion breeder with ceramic fuel particles

In the present study, hydrogen production potential of SOlid Moving BREeder ReactOr (SOMBRERO) fusion reactor and heat recovery of this system is investigated. The original SOMBRERO fusion reactor has a 1000 MWe KrF laser-driven IFE power plant. This reactors fusion power is 2677 MW and total thermal power is 2891 MW. The blanket is divided into three breeding zone and these breeding zones have different C, Li₂O and ceramic fuel particles. One-dimensional neutronic calculations of SOMBRERO fusion reactor have been performed by using XSDRNPM/SCALE4.4a neutron transport code. Steam Methane Reforming (SMR) method is used for large-scale hydrogen production and heat recovery of waste heat is analyzed. The numerical results show that the considered SOMBRERO fusion reactor has a good neutronic performance as well as the high hydrogen production potential with heat recovery of SMR process.     

Large‐scale energy production with thorium in a typical heavy‐water reactor using high‐grade plutonium as driver fuel

Thorium can be introduced into the energy vector in combination with high‐grade plutonium (HG‐Pu). Excellent neutron economy of heavy‐water moderator allows use of mixed ThO₂/HG‐PuO₂ fuel in heavy‐water reactors with high efficiency, leading to the exploitation of large world thorium reserves and extending the availability of the nuclear energy by two orders of magnitude. In the present work, the criticality calculations have been performed with the code MCNPX 3‐D geometrical modeling of a typical heavy‐water reactor, where the structure of all fuel rods and bundles is represented individually. In the course of time calculations, nuclear transformation and radioactive decay of all actinide elements as well as fission products are considered. Five different fuel compositions have been selected for investigations: (1) 97% thoria (ThO₂) + 3% PuO₂; (2) 96% ThO₂ + 4% PuO₂; (3) 95% ThO₂ + 5% PuO₂; (4) 94% ThO₂ + 6% PuO₂; and (5) 92% ThO₂ + 8% PuO₂. The behavior of the criticality k_∞ and the burn‐up values of the reactor have been pursued by full power operation at 640 MW_el (2180 MW_th) for approximately 7 years. Time calculations have been conducted with MCNPX and CINDER codes under consideration of all nuclear transformation and radioactive decay processes on the actinide isotopes and fission fragments. As the reactor allows fuel recharging at on‐power operation mode, the reactor criticality has been followed down to k_eff,end = ~1.05. The corresponding burn‐up values and operation periods for the investigated modes are (1) 18 GWd/MT and 780 days; (2) 27 GWd/MT and 1200 days; (3) 35 GWd/MT and 1560 days; (4) 44 GWd/MT and 1940 days; and (5) 60 GWd/MT and 2640 days. Among the investigated four modes, 94% ThO₂ + 6% PuO₂ seems a reasonable choice under consideration of the high price of the HG‐Pu as driver fuel. The mixed fuel has the potential of an extensive exploitation of thorium resources. Reactor will run with the same fuel charge for approximately 5 years and allow a fuel burn‐up approximately 44 GWd/MT, comparable with conventional light‐water reactors (LWRs). Plutonium component of the mixed fuel will become nonprolific after few months of plant operation through the accumulation of even isotopes. Addition of few percent natural uranium to the initial mixed fuel charge will keep the ²³³U component below 22% and hence at nonprolific level over the entire plant operation period. Replacement of 4% ThO₂ with 4% nat‐UO₂ will practically not change main technical parameters of the reactor.     

Hydrogen production via water splitting process in a molten-salt fusion breeder

This study presents the hydrogen production and fissile breeding potentials of Force-Free Helical Reactor (FFHR) fueled with the molten-salt mixtures. The sulfur–iodine (S–I) thermochemical water-splitting and high-temperature electrolysis cycles, which are the most promising water-splitting cycles, are selected to produce large-scale and pure hydrogen. The XSDRNPM/SCALE4.4a neutron transport code is used for the neutronic calculations. The analyses have been performed individually for four different molten-salt mixtures, (pure FLiBe, mixture of FLiBe and ThF₄, mixture of FLiBe and UF₄, and mixture of FLiBe, ThF₄ and ²³³UF₄). The numerical results bring out that the considered molten-salt fusion breeder reactor has a high neutronic performance and can produce a considerable amount of the hydrogen production (up to 40 kg/s), as well as the fissile fuel (up to 2.5 tons/yr).     

Toluene addition to turbulent H2/natural gas flames in bluff-body burners

A key challenge in the transition towards using hydrogen as an alternative carbon-free fuel is the reduced thermal radiation due to the absence of soot. A novel solution to this may be doping with highly sooting bio-oils. This study investigates the efficacy of toluene as a prevapourised dopant in turbulent pure hydrogen and blended hydrogen/natural gas flames as a means of improving soot loading and radiant heat transfer. All flames are stabilised on bluff-body burners to emulate the recirculation component of many industrial combustors. Total heat flux and illuminance increase non-linearly with toluene concentration for fuel blends and bluff-body diameters. By reducing the bluff-body diameter from 64 mm to 50 mm, a 20/80 (vol%) H₂/natural gas mixture produces a more radiative flame than a 10/90H₂/natural gas mixture in the smaller bluff-body. Opposed-flow flame simulations of soot precursors indicate that as strain rate increases, although overall soot precursor concentration decreases, a 20 vol% hydrogen mixture will produce more soot than a 10 vol% mixture. This suggests the addition of hydrogen up to 20 vol% may be beneficial for soot production in high strain environments.     

Air gasification of high-ash sewage sludge for hydrogen production: Experimental,sensitivity and predictive analysis

In this work, air gasification of sewage sludge was conducted in a lab-scale bubbling fluidized bed gasifier. Further, the gasification process was modeled using artificial neural networks for the product gas composition with varying temperatures and equivalence ratios. Neural network-based prediction will help to predict the hydrogen production from product gas composition at various temperatures and equivalence ratios. The gasification efficiency and lower heating values were also established as a function of temperatures and equivalence ratios. The maximum H₂ and CO was recorded as 16.26 vol% and 33.55 vol%. Intraileally at ER 0.2 gas composition H₂, CO, and CH₄ show high concentrations of 20.56 vol%, 45.91 vol%, and 13.32 vol%, respectively. At the same time, CO₂ was lower as 20.20 vol% at ER 0.2. Therefore, optimum values are suggested for maximum H₂ and CO yield and lower concentration of CO₂ at ER 0.25 and temperature of 850 °C. A predictive model based on an Artificial Neural network is also developed to predict the hydrogen production from product gas composition at various temperatures and equivalence ratios. The network has been trained with different topologies to find the optimal structure for temperature and equivalence ratio. The obtained results showed that the regression coefficients for training, validation, and testing are 0.99999, 0.99998, and 0.99992, respectively, which clearly identifies the training efficiency of the trained model.     

Optimal design of a sleeve-type steam methane reforming reactor for hydrogen production from natural gas

The three-dimensional computational fluid dynamics (CFD) model was used in a sleeve-type steam methane reforming (SMR) reactor for H₂ production of 2.5 Nm³/h from natural gas. The feed and combustion gases acted as a counter-current heat exchange owing to a narrow sleeve equipped between the combustor and catalyst-bed. The CFD results were validated against the experimental data of the SMR reactor with a sleeve gap size of 3 mm. The effect of the sleeve gap size and the flame shape on process performances such as H₂ production rate, thermal efficiency, and uniformity of catalyst-bed temperature was investigated using the CFD model. The sleeve gap size influenced the gas velocity inside the sleeve gap and the convective heat transfer. The SMR reactor with a sleeve gap size of 7 mm showed the highest H₂ production rate and thermal efficiency when comparing six sleeve gap sizes ranging from 2 to 10 mm. A new flame shape for the SMR reactor with the sleeve gap size of 7 mm was proposed to improve the process performances.     

A strategy of mid-temperature natural gas based chemical looping reforming for hydrogen production

Steam methane reforming (SMR) needs the reaction heat at a temperature above 800 °C provided by the combustion of natural gas and suffers from adverse environmental impact and the hydrogen separated from other chemicals needs extra energy penalty. In order to avoid the expensive cost and high power consumption caused by capturing CO₂ after combustion in SMR, natural gas Chemical Looping Reforming (CLR) is proposed, where the chemical looping combustion of metal oxides replaced the direct combustion of NG to convert natural gas to hydrogen and carbon dioxide. Although CO₂ can be separated with less energy penalty when combustion, CLR still require higher temperature heat for the hydrogen production and cause the poor sintering of oxygen carriers (OC). Here, we report a high-rate hydrogen production and low-energy penalty of strategy by natural gas chemical-looping process with both metallic oxide reduction and metal oxidation coupled with steam. Fe₃O₄ is employed as an oxygen carrier. Different from the common chemical looping reforming, the double side reactions of both the reduction and oxidization enable to provide the hydrogen in the range of 500–600 °C under the atmospheric pressure. Furthermore, the CO₂ is absorbed and captured with reduction reaction simultaneously.Through the thermodynamic analysis and irreversibility analysis of hydrogen production by natural gas via chemical looping reforming at atmospheric pressure, we provide a possibility of hydrogen production from methane at moderate temperature. The reported results in this paper should be viewed as optimistic due to several idealized assumptions: Considering that the chemical looping reaction is carried out at the equilibrium temperature of 500 °C, and complete CO₂ capture can be achieved. It is assumed that the unreacted methane and hydrogen are completely separated by physical adsorption. This paper may have the potential of saving the natural gas consumption required to produce 1 m³ H₂ and reducing the cost of hydrogen production.     

A numerical study on the active reaction thickness of nickel catalyst layers used in a low-pressure steam methane reforming process

With the advancement of fuel cell technologies and growing interest in the hydrogen economy, the small-scale, distributed production of hydrogen has recently been receiving considerable research attention. The steam methane reforming (SMR) process, an established industrial process for large-scale hydrogen production, can also be successfully deployed for small-scale, low-pressure hydrogen production systems, including compact reformers, microchannel reformers, plate reformers, and monolithic reformers. In this study, the active reaction thickness of nickel catalyst layers was numerically determined by solving one-dimensional reaction/diffusion problems with finite volume method. The small-scale SMR conditions were considered, such as the reforming pressure of 1–3 bar, reforming temperature of 600–800 °C, and steam-to-carbon ratio of 2–4. The results showed the active thickness for the steam reforming and reverse methanation reactions hardly exceeded 0.15 mm for 600 °C, 0.07 mm for 700 °C, and 0.05 mm for 800 °C, at the reforming pressure of 1 bar. Besides, the effects of the volume-specific nickel surface area and diffusion properties were also investigated.     

Viscosity and thermal conductivity of dispersions of sub-micron TiO2 particles in water prepared by stirred bead milling and ultrasonication

Experiments were carried out on the preparation of dispersions of sub-micron TiO₂ particles in water by stirred bead milling, for potential use as coolants. The prepared dispersions were characterized through the measurement of particle size distribution, zeta potential, viscosity and thermal conductivity. The effects of particle concentration (0.27–1.39 vol%), ultrasonication time (0–7 h) on viscosity and thermal conductivity have been studied. The effect of temperature (29–55 °C) on viscosity has also been investigated. The results indicate that the ultrasonication can be utilized to tailor the transport properties of the sub-micron dispersions produced by stirred bead milling. The entire particle size distribution data has been utilized to develop correlations for prediction of relative viscosity and thermal conductivity ratio of these dispersions. These dispersions possess higher thermal conductivity than water and can also be utilized as coolants.     

Economic competitiveness of compact steam methane reforming technology for on-site hydrogen supply: A Foshan case study

On-site hydrogen production through steam-methane reforming (SMR) from city gas or natural gas is believed to be a cost-effective way for hydrogen-based infrastructure due to high cost of hydrogen transportation. In recent years, there have been a lot of on-site hydrogen fueling stations under design or construction in China. This study introduces current developments and technology prospects of skid-mounted SMR hydrogen generator. Also, technical solutions and economic analysis are discussed based on China's first on-site hydrogen fueling station project in Foshan. The cost of hydrogen product from skid-mounted SMR hydrogen generator is about 23 CNY/kg with 3.24 CNY/Nm³ natural gas. If hydrogen price is 60 CNY/kg, IRR of on-site hydrogen fueling station project reaches to 10.8%. While natural gas price fall to 2.3 CNY/Nm³, the hydrogen cost can be reduced to 18 CNY/kg, and IRR can be raised to 13.1%. The conclusion is that skid-mounted SMR technology has matured and is developing towards more compact and intelligent design, and will be a promising way for hydrogen fueling infrastructures in near future.     

Application of laser fusion to the radiolytic production of hydrogen

A preliminary conceptual design of a plant to produce hydrogen by laser-fusion-induced steam radiolysis has been developed. It consists of a suppressed ablation lithium wetted wall cavity surrounded by pure and borated steam regions in which fusion neutrons deposit a substantial fraction of their energy, causing nuclear heating in the steam and structural materials, as well as radiolysis of water molecules. Coupled photon-neutron transport calculations have been performed to determine the energy deposited in the different regions of the reactor, and subsequently the amount of hydrogen and nuclear heating generated for various sets of reactor dimensions. The results of these calculations have been used to perform an economic analysis based on scaled costs of the corresponding component systems of proposed laser fusion power plants and hydrogen-generating or handling facilities. The production costs of hydrogen and electric power produced by the laser fusion hydrogen/electric plant considered have been estimated. It has been found that within the uncertainty of these estimates, and for laser fusion output parameters reasonably expected for a first-generation reactor, the computed hydrogen and electric power production costs are not competitive with current prices of natural gas and oil, and electrical power generated by alternate means. However, with an extension of the expected range of output values to significantly higher pellet gains, hydrogen production could become economically attractive.     

Kinetics of non-premixed hydrogen–oxygen catalytic recombination reaction at ambient temperature

This study proposes the use of the hydrogen–oxygen catalytic recombination reaction to safely eliminate the leaked hydrogen in a confined environment. Experiments on the hydrogen–oxygen reaction catalyzed by using Pt/C as a catalyst are conducted at ambient temperature in a small cylindrical vessel. The macroscopic kinetic process of the hydrogen–oxygen recombination reaction is investigated, and the effects of the reaction parameters, such as the initial hydrogen volume fraction and catalyst layer position, on the reaction temperature and hydrogen conversion are examined. The reaction temperature and temperature rise rate are shown to reach the maximum values when the initial hydrogen fraction is 70 vol%. When the initial hydrogen fraction is ≤ 67 vol%, the hydrogen conversion reaches 100%. After the initial hydrogen fraction is > 67 vol%, the hydrogen conversion decreases significantly, and the hydrogen conversion is only 53% for the initial hydrogen fraction is up to 80 vol%. Moreover, the position of the catalyst layer has a significant effect on the reaction rate and heat distribution inside the vessel. When the catalyst layer is near the bottom of the reaction vessel, the reaction rate is accelerated and the released heat accumulates at the bottom of the vessel. The influence law of the aforementioned factors can provide a technical reference for applications of the hydrogen–oxygen catalytic reaction.     

Catalytic activity and underlying atomic rearrangement in monolayer CoOOH towards HER and OER

For efficient hydrogen and oxygen production, design and synthesis of cost-effective, stable and active materials are inevitable. In this work, the catalytic activity of 2D CoOOH towards hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) has been investigated using first principles calculations based on density functional theory. The adatom induced structural rearrangement have been investigated from structural parameters as well as charge redistribution in 2D CoOOH. The preferred site for hydrogen and oxygen adsorption were found to be the top site of oxygen atom of 2D CoOOH. The catalytic activity of HER and OER towards 2D CoOOH was studied by calculating the Gibbs free energy. Our study revealed that the 2D CoOOH serve better as a catalyst for HER than OER with adsorption energy of −0.45 and −3.68 eV respectively suggesting its efficient use for hydrogen production. We further investigated the changes in electronic properties of 2D CoOOH on adsorption of hydrogen and oxygen atom.     

A modified steam-methane-reformation reaction for hydrogen production

Hydrogen is mostly produced by the Steam Methane Reforming (SMR) reaction which adds many tonnes of carbon emissions to the environment for each tonne of hydrogen. A modified scheme for carbon-emission free production of hydrogen, which involves sodium hydroxide, methane and steam, has been explored here. The modification of the SMR reaction isCH₄ + 2NaOH + H₂O = Na₂CO₃ + 4H₂The modified reaction has several advantages: it does not require catalysis, the temperature of reaction is considerably reduced and the products are industrially important. By this process, we can produce hydrogen without any carbon dioxide emission as shown in this theoretical and experimental study. The reaction has been studied in the temperature range of 873-1073 K in an open configuration for 30 min and at various methane and constant water vapor flow. It is determined that at a methane flow rate of 25 ml/min the reaction is 98% complete at 873 K.     

Low carbon hydrogen production in Canada via natural gas pyrolysis

Large scale, low cost, and low carbon intensity hydrogen production is needed to reduce emissions in the energy and transportation sectors. We present a techno-economic analysis and life cycle assessment of natural gas pyrolysis technologies for hydrogen production, with carbon black (CB) as a co-product. Four designs were considered based on the source of heat to the pyrolysis system, the combustion medium, and use of carbon capture (CC) technology. The oxygen-fired-CB design with CC is the most attractive from financial and environmental perspectives, superior to a conventional steam methane reformer (SMR) process with CC. The estimated pre-tax minimum hydrogen selling prices for the pyrolysis technologies range between $1.08/kg and $2.43/kg when natural gas (NG) costs $3.76/GJ. Key advantages include near-zero onsite GHG emissions of the oxygen-fired-CB design with CC and up to 41% lower GHG emissions compared to the SMR + CC process. The results indicate that natural gas pyrolysis may be a feasible pathway for hydrogen production.     

Improved design of metal-organic frameworks for efficient hydrogen storage at ambient temperature: A multiscale theoretical investigation

A multiscale theoretical technique is used to examine the combination of different approaches for hydrogen storage enhancement in metal-organic frameworks at room temperature and high pressure by implementation lithium atoms in linkers. Accurate MP2 calculations are performed to obtain the hydrogen binding sites and parameters for the following grand canonical Monte Carlo (GCMC) simulations. GCMC calculations are employed to obtain the hydrogen uptake at different thermodynamic conditions. The results obtained demonstrate that the combination of different approaches can improve the hydrogen uptake significantly. The hydrogen content reaches 6.6 wt% at 300 K and 100 bar satisfying DOE storage targets (5.5 wt%).