Hybrid Reactor Research Articles

Synthesis of La0.8Zn0.2MnO3 nanocatalysts for decomposition of VOCs in a DBD plasma reactor; Influence of sol-gel parameters

In this study, La0.8Zn0.2MnO3 nanocatalysts were synthesized using sol-gel method at different citric acid to metal nitrate (C/N) ratios and different calcination temperatures. The synthesized catalysts were used for oxidation of benzene, toluene, and xylene (BTX) in a catalytic-plasma hybrid reactor at different input voltages of 5, 7.5, 10, 12.5, and 15 kV. The synthesized catalysts were analyzed by XRD, FESEM, EDX, FTIR, BET, and TEM. XRD analysis confirmed the effect of calcination temperature on crystalline degree of LnMnO3 phase in perovskite La0.8Zn0.2MnO3 catalyst. TEM analysis also confirmed production of particles in nanometer range. Moreover, FTIR and BET analyses indicated that C/N ratio has a direct effect on the amount of metal oxide functional groups and surface area of the resultant catalyst, respectively. The reactor tests showed that the use of C/N= 0.5 and calcination temperature of 700°C in catalyst preparation resulted in the best performance in BTX oxidation. Increasing the voltage up to 15 kV had a good effect on the oxidation ability of the catalyst as well. In these conditions, the highest oxidation percentages of benzene, toluene and xylene were equal to 90.00, 89.86, and 88.64 %, respectively.

Neutronics Analysis of the Stellarator-Type Fusion–Fission Hybrid Reactor Using Mesh Simplification

The stellarator plasma device has been widely studied as one of the candidate solutions paralleling the ITER project, and its coupling with a fission blanket can bring benefits promoting the development of fusion technology with stable energy production simultaneously. However, the neutronics optimization design for the stellarator-type Fusion-Fission Hybrid Reactor (FFHR) is extremely complex since the helical structure with a large amount of spline curved surfaces cannot be exactly described in most of the Monte Carlo simulation processes, and the preliminary design stage has also been a time-consuming and error-prone task with the requirements frequently changing. In this context, the mesh-oriented optimized method has been considered for the parametric modeling analysis in order to get the ideal structure without redundant topologic information, and the corresponding conversion process from computer-aided design (CAD) to Monte Carlo simulation has been fulfilled by the CAD-PSFO code. Moreover, the liquid type of thorium-uranium fuels has been selected as the solutes dissolve in the molten salt blanket with its multilayer structure, where the burnup feature and neutronics properties have been analyzed and explained with the help of the OMCB code. The stellarator-type FFHR has been designed as a compact multifunctional device that can incinerate plutonium and transmute the minor actinide isotopes with tritium self-sufficiency and the high-energy multiplication factor.

Design and Performance Test of Ozone-Plasma Hybrid Reactor for Phenol Waste

The research on phenolic compound degradation using chemical oxidation methods in a plasma reactor was performed with an Ozone-Plasma Hybrid Reactor (RHOP). This device operates by combining ozonation reactions in the liquid plasma within the reaction room. Furthermore, Ozone gas as a reagent is produced by the standard ozonator type Resun RSO-9805 made in Hong Kong and fed into this device, where the liquid phase is mixed within the injector. This way, the two-phase mixture reacts more intensively in RHOP. Also, this combination is designed to intensify hydroxyl radicals while the liquid phase is in an alkaline condition constantly exposed to plasma. The results demonstrated a continuous circulation for 2 hours at the initial concentration of 50 ppm for p-chlorophenol with a volume of 2 liters. This further obtained an 83.98% removal rate and 42.19% COD value decrease.

Optimization of Hydraulic Retention Time and Organic Loading Rate in Anaerobic Digestion of Squeezed Pineapple Liquid Wastes for Biogas Production

Pineapple wastes are produced in huge amount during the industrial canning process of pineapple; in Thailand over 400,000 tons per annum of canned pineapple exported leaving behind the waste. Besides the pulps and peels as solid wastes, the squeezed pineapple liquid wastes (SPLW) extracted from solid wastes can also be used for anaerobic digestion. In the present study, the anaerobic digestion of liquid squeezed from industrial pineapple peels was carried out using a lab-scale hybrid reactor. The reactor was operated for over 170 days with the hydraulic retention time (HRT) of 20 days decreasing down to 5 days and simultaneous control of organic loading rate (OLR). Under controlled conditions in the hybrid reactor, pH was maintained at 6.5–7.6 by adding alkaline for anaerobic microbial activity. Results showed that the chemical oxygen demand (COD) removal efficiency was at ≥ 90% for all conditions. The biogas production (mL/day) increased thoroughly from longer HRT to shorter HRT, as same as methane production with the maximum values (HRT 5 days, OLR 5 g/COD/ day with recirculation) of 55,130 and 30,322 mL/day, respectively. Moreover, the highest yields of biogas and methane were also investigated under similar conditions with the values of 0.504 and 0.277 L/gCOD, respectively. Interestingly, this optimization of both HRT and OLR of lab-scale anaerobic digestion process could be further practically applied to pilot or industrial scale in canned pineapple factories for biogas production.

Performance evaluation of an anaerobic hybrid reactor treating petrochemical effluent

Organic loading rate (OLR), Hydraulic Retention Time (HRT) and up flow velocity are important parameters significantly affecting microbial ecology and characteristics of anaerobic reactors. In this study, Performance of an anaerobic hybrid reactor (UASB/Filter) at mesophilic condition was evaluated in a 15.4 L reactor receiving petrochemical wastewater. The temperature of influent was adjusted by an inline heat exchanger at around 35 ˚C. The reactor was seeded with flocculent sludge from a UASB plant treating dairy wastewater. The sludge was acclimatized to petrochemical wastewater in twostage operation. After 39 weeks, a COD reduction of 70.3% was obtained at OLR=2.0 kg m-3 d-1 and HRT=18 h. Under steady state conditions, experiments were conducted at OLRs of between 0.5 and 24 kg TCOD m-3 d-1 , hydraulic retention times (HRT) of 4-48 h and up flow velocities 0.021-0.25 m h-1. Removal efficiencies in the range of 42-86% were achieved at feed TCOD concentrations of 1000- 4000 mg L-1 . The biogas production data used for determination of biogas production kinetics. The values of Gmax and GB estimated as 11.173 LL-1d -1 and 85.83 g L-1d -1 , respectively.

Combined Iron-Loaded Zeolites and Ozone-Based Process for the Purification of Drinking Water in a Novel Hybrid Reactor: Removal of Faecal Coliforms and Arsenic

This study was carried out to provide a novel solution to treat drinking water at household levels, specifically removing arsenic (As) and faecal coliforms (microbes). In the current investigation, a synergistic iron-loaded zeolites and ozonation process (O3/Fe-ZA) was used for the first time in a modified batch reactor to remove coliform bacteria and arsenic in tap water. Moreover, the study utilizes the human health risk assessment model to confirm the health risk due to As intake in drinking water. The risk assessment study revealed a health risk threat among the residents suffering from the adverse effects of As through its intake in drinking water. Furthermore, the results also suggested that the O3/Fe-ZA process significantly removes faecal coliforms and As, when compared with single ozonation processes. Additionally, the ozone dose 0.2 mg/min and Fe-ZA dose of 10 g (in the O3/Fe-ZA process) gives the maximum removal efficiency of 100% within 15 min for faecal coliform removal. In 30 min, the removal efficiency of 88.4% was achieved at the ozone dose of 0.5 mg/min and 93% removal efficiency was achieved using 10 g Fe-ZA for the removal of As in the O3/Fe-ZA process. Hence, it was concluded that the O3/Fe-ZA process may be regarded as an effective method for removing faecal coliforms and As from drinking water compared to the single ozonation processes.

Silicon Carbide Ceramic as Fast Neutron Detector of Fission and Fusion Reactions in Fusion–Fission Hybrid Reactors

Silicon Carbide Ceramic as Fast Neutron Detector of Fission and Fusion Reactions in Fusion–Fission Hybrid Reactors

A life cycle assessment of energy recovery using briquette from wastewater grown microalgae biomass

Microalgae biomass (MB) is a promising source of renewable energy, especially when the cultivation is associated with wastewater treatment. However, microalgae wastewater technologies still have much to improve. Additionally, microalgae biomass valorization routes need to be optimized to be a sustainable and feasible source of green bioenergy. Thus, this paper aimed to evaluate the environmental impacts of the production of briquettes from MB, cultivated during domestic wastewater treatment. Also, it was evaluated how much the drying of the MB affected the life cycle and the environment. Improvements in the life cycle to mitigate the environmental impacts of this energy route were proposed. Cradle-to-gate modeling was applied to obtain a life cycle assessment (LCA) from cultivation to the valorization of MB, through its transformation into a solid biofuel. With LCA, it was possible to identify which technical aspect of the process needs to be optimized so that environmental sustainability can be achieved. Two scenarios were compared, one with the microalgae growth in a high-rate algal pond (HRAP) (scenario 1) and the other in a hybrid reactor, formed by a HRAP and a biofilm reactor (BR) (scenario 2). LCA highlighted the electric power mix, representing, on average, 60% of the total environmental impacts in both scenarios. The valorization of MB in briquettes needs to consume less energy to offset its yield. The environment suffered pressure in freshwater eutrophication, due to the release of 3.1E-05 and 3.9E-05 kg of phosphorus equivalent; in fossil resources scarcity, with the extraction of 1.4E-02 and 4.5E-02 kg of oil equivalent; and in climate change, by the emission of 1.0E-01 and 1.9E-01 kg of carbon dioxide (CO2) equivalent, in scenarios 1 and 2, respectively. Scenario 1 was highly damaging to terrestrial ecotoxicity, with the release of 3.5E-01 kg of 1,4 Dichlorobenzene, coming from the CO2 used in MB growth. This category was the one that most negatively pressured the environment, differing from scenario 2, in which this input was not required. This was the only impact category in which scenario 2 had a better environmental performance when compared to scenario 1. Cotton, required in scenario 2, represented up to 87% of emissions in some of the evaluated categories. Despite the impacts that occurred in the two modeled scenarios, the environmental gains due to the use of wastewater for microalgae growth, replacing the synthetic cultivation medium, stood out. In the sensitivity analysis, two alternative scenarios were proposed: (i) electricity consumption for drying has been reduced, due to the natural decrease of MB humidity, and (ii) MB briquettes were considered a substitute for coal briquettes. Results indicated that pressures on climate change and fossil resource scarcity were eliminated in both scenarios and this also occurred for freshwater eutrophication in scenario 2. This paper contributes to the improvement and development of converting MB routes into more sustainable products, causing less pressure on the environment. Also, the study contributes to filling a gap in the literature, discussing methods and technologies to be improved, and consequently making microalgae biotechnology environmentally feasible and a potential renewable energy alternative.

Simultaneous nitrification/denitrification and desulfurization of wastewater polluted with ammonium, COD and sulfide: effectiveness of a new up-flow vertical hybrid reactor.

Industrial wastewater discharges pose an environmental risk. Here, the effectiveness of an up-flow vertical hybrid system, operating with synthetic and industrial wastewater was investigated, as a new approach to perform nitrification/denitrification and desulfurization within a single reactor. The hybrid reactor is divided in two reaction zones, the oxic and anoxic. The removal of chemical oxygen demand (COD), ammonium, and sulfide was investigated, highlighting changes in microbial diversity. The reactor was evaluated at hydraulic residence time (HRT) of 1.6days, and its performance throughout 180days is presented in four stages. In stages I-II, high COD and ammonium removal was obtained with synthetic wastewater. In stage-III, sulfide-rich synthetic wastewater did not alter the system, attaining COD, ammonium, and sulfide removal efficiencies of 81, 99.5, and 99.7%, respectively. In the last stage, a mixture of effluents was fed into the reactor at loading rates of 277mg COD/L-d, 46.5mg NH4 +-N /L-d, and 15mg HS--S /L-d. Sulfide and ammonium removals were 100% and 99.9%, respectively. However, low COD removal was observed, being of 51%, and the system removed 97% in terms of BOD5. The structure and microbial diversity also changed. Sulfide feeding, induced the proliferation of sulfur oxidizers like Thiomiscropira and Thiobacillus. Industrial wastewater enhanced the abundance of Pseudomonas (15.53%) and favored the proliferation of new bacteria of the genus Truepera (2.98%) and Alicyclipilus (7.56%). This is the first study reporting simultaneous nitrification/denitrification and desulfurization to remove ammonium, COD and sulfide from complex industrial wastewater using an up-flow vertical hybrid reactor.

Sulfate reducing ammonium oxidation (SULFAMMOX) process under anaerobic conditions

Sulfate (SO42−) can be an electron acceptor for ammonium nitrogen (NH4+) oxidation under anaerobic conditions. The process is known as sulfammox and can be a viable alternative to conventional, nitrite (NO2−) dependent, anammox. Two bacterial species, including Bacillus Benzoevorans and Brocadia Anammoxoglobus Sulfate, can perform that process. With sulfammox, an economically inefficient pre-nitration step (due to aeration) is not required. There are more than 10 different systems in which sulfammox has been studied, including suspended growth, biofilm, granular and hybrid reactors. A combination of anammox and sulfur related processes (sulfammox and autotrophic denitrification) would especially be appropriate for specific industrial wastewater with high content of nitrogen compounds and SO42−. The results of recent studies suggest that very high removal efficiencies could simultaneously be achieved with respect to both NH4+ (92%–99%) and SO42− (53%–60%).

PHENOL WASTE TREATMENT USING OZONE-PLASMA HYBRID REACTOR

Phenol is one of the most dangerous ingredients in industrial wastewater, which has acute toxicity and is difficult to degrade in the environment. Therefore, Ozone-Plasma Hybrid Reactor (RHOP) is an effective phenol waste treatment used to test the performance of the treatment of synthetic phenolic compounds. Its working principle is based on the combination of ozonation reaction in the liquid plasma field of the reactor. Ozone as a reagent is produced by the ozonator, which is fed into the RHOP by mixing it with the liquid phase feed in the injector to enable the intensive the reaction of the two-phase mixture react. Furthermore, the two-phase mixture intensifies hydroxyl radicals when the liquid phase is in alkaline condition and continuously exposed in plasma. The results obtained from the performance test carried out on several wastes with high concentrations, showed that the system needed improvement. The improvements were made by changing the reactor system to Dielectric Barrier Discharge (DBD) plasma with wire cylinder configuration, to degrade synthetic waste containing phenolic compounds through active species formed in the reactor. This process has a high oxidation potential and decomposes various organic pollutants in waste. Furthermore, the ozonation technique was applied to the DBD reactor with the aim of increasing the amount of ozone and OH• radicals, therefore maximizing the phenol degradation process.

Treatment of slaughterhouse wastewater by upflow anaerobic hybrid reactor at pilot scale

Treatment of slaughterhouse wastewater by upflow anaerobic hybrid reactor at pilot scale

Bifurcation Analysis of an Impulsive System Describing Partial Nitritation and Anammox in a Hybrid Reactor.

Low-energy nitrogen removal under mainstream conditions is a technology that has received significant attention in recent years as the water industry drives toward long-term sustainability goals. Simultaneous partial nitritation-Anammox (PN/A) is one process that can provide substantial energy reduction and lower sludge yields. Mathematical modeling of the PN/A process offers engineers insights into the operating conditions necessary to maximize its potential. Laureni et al. (Laureni et al. Water Res. 2019, 14) have recently published a simplified mechanistic model of the process operated as a sequencing batch reactor that investigated the effect of three key operating parameters on performance (Anammox biofilm activity, dissolved oxygen concentration and fraction of solids wasted). The analysis of the model was limited, however, to simulation with relatively few discrete parameter sets. Here, we demonstrate through the use of bifurcation theory applied to an impulsive dynamical system that the parameter space can be partitioned into regions in which the system converges to different fixed points that represent different outcomes: either the washout of nitrite-oxidizing bacteria or their survival. Mapping process performance data onto these spaces allows engineers to target suitable operating regimes for specific objectives. Here, for example, we note that the nitrogen removal efficiency is maximized close to the curve that separates the regions in parameter space where nitrite-oxidizing bacteria washout from the region in which they survive. Further, control of solids washout and Anammox biofilm activity can also reduce oxygen requirements while maintaining an appropriate hydraulic retention time. The approach taken is significant given the possibility for using such a methodology for models of increasing complexity. This will enable engineers to probe the entire parameter space of systems of higher dimension and realism in a consistent manner.

Взаимодействие изотопов водорода с ферритно-мартенситной сталью ЭК-181 (Русфер). Обзор полученных результатов

Ferritic-martensitic steel with rapid decay of activity EK-181 (Rusfer-EK-181, Fe – 12 Cr – 2 W – V – Ta – B) was developed in Russia (A.A. Bochvar Institute) as a structural material for use in the active zones of fast neutron reactors, as well as in thermonuclear and hybrid reactors. The team of authors has been studying various aspects of hydrogen interaction with Rusfer steel for a number of years, primarily retention, diffusion, and the effect of various damages on capture. The paper summarizes the results of the research performed by the authors.

Criticality Search of an Accelerator Driven System Using the ANET Code

One of the most important safety parameters taken into consideration during the design and actual operation of a nuclear reactor is its control rods adjustment to reach criticality. Concerning the conventional nuclear systems, the specification of their rods’ position through the utilization of neutronics codes, deterministic or stochastic, is considered nowadays trivial. However, innovative nuclear reactor concepts such as the Accelerator Driven Systems require sophisticated simulation capabilities of the stochastic neutronics codes since they combine high energy physics, for the spallation-produced neutrons, with classical nuclear technology. ANET (Advanced Neutronics with Evolution and Thermal hydraulic feedback) is an under development stochastic neutronics code, able to cover the broad neutron energy spectrum involved in ADS systems and therefore capable of simulating conventional and hybrid nuclear reactors and calculating important reactor parameters. In this work, ANETS’s reliability to calculate the effective multiplication factor for three core configurations containing control rods of the Kyoto University Critical Assembly, an operating ADS, is examined. The ANET results successfully compare with results produced by well-established stochastic codes such as MCNP6.1.

Enhancement of Biogas Production from Co-Digestion of Industrial Solid Pineapple Wastes by Two-Stage Anaerobic Digestion Systems

This study aimed to investigate the biogas and methane production, as well as the COD removal efficiency by AD from pineapple solid wastes (PSW) as co-digestion feedstock. The two-stage of anaerobic digestion system was configured as continuously stirred tank reactor (CSTR) installed with anaerobic hybrid reactor (AHR) in order to enhance the efficiency and stability in biogas production. The PSW were firstly characterized for chemical composition. Then, the total solids (TS) were controlled as 4% of TS in influent loadings and four different HRTs were determined to investigate the subsequent effects, such as pH, total volatile acids and alkaline (TVA/Alk) ratio, biogas and methane production, and COD removal efficiency. The results demonstrated that the overall pH condition in CSTR was more acidic than AHR system and simultaneously performed in less stability of AD process by presence of massive TVA/Alk ratio. Furthermore, the maximum biogas production and COD removal efficiency were also observed in AHR system at 2,702 mL and 80.53% under HRT7 and HRT15, respectively. Interestingly, more than thousand millilitres of biogas production were dramatically increased from CSTR system under parallel operation. Thus, the separated acidogenic and methanogenic stage in two-stage system obviously improved the potential of AD process. However, the methane yields in AHR system remained stable in the range of 0.16-0.19m3/kgCOD removed, excepted at the lowest HRT condition (HRT5) by increasing OLRs. Thus, the optimal conditions for biogas production and COD removal could be varied, which depending on the types of feedstocks and operational reactors.

Ozonation-assisted electro-membrane hybrid reactor for oily wastewater treatment: A methodological approach and synergy effects

Abstract Wastewater produced from oil and gas industries contains high levels of organic and inorganic pollutants in the form of emulsions sized below 10 μm. The beneficial reuse of oily wastewater requires advanced treatment methods to remove these emulsions and promote cleaner production. This work has attempted to investigate the hybridization of electrocoagulation (EC) process, ceramic microfiltration membrane, and ozonation as a one-pot solution for the treatment of oily wastewater. The variables in this study included hydraulic retention time (HRT), aeration, current density (CD), mode of power supply, and initial pH of the sample. Aerated electro-membrane reactor contributed to a maximum COD reduction of 18.0% as opposed to 53.1% for the ozonated reactor. The effectiveness of the novel hybrid reactor could be attributed to the enhancement of electrocoagulation process by the ozone, which facilitated size-exclusion by the submerged membrane. Scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDS) were performed to characterize the generated foam, electrodes, and sludge. The present findings indicate that the ozonation-assisted electro-membrane hybrid method has the potential to be employed for the treatment of oily wastewater.

Thermophilic Anaerobic Digestion of Second Cheese Whey: Microbial Community Response to H2 Addition in a Partially Immobilized Anaerobic Hybrid Reactor

In this study, we investigated thermophilic (55 °C) anaerobic digestion (AD) performance and microbial community structure, before and after hydrogen addition, in a novel hybrid gas-stirred tank reactor (GSTR) implemented with a partial immobilization of the microbial community and fed with second cheese whey (SCW). The results showed that H2 addition led to a 25% increase in the methane production rate and to a decrease of 13% in the CH4 concentration as compared with the control. The recovery of methane content (56%) was reached by decreasing the H2 flow rate. The microbial community investigations were performed on effluent (EF) and on interstitial matrix (IM) inside the immobilized area. Before H2 addition, the Anaerobaculaceae (42%) and Lachnospiraceae (27%) families dominated among bacteria in the effluent, and the Thermodesulfobiaceae (32%) and Lachnospiraceae (30%) families dominated in the interstitial matrix. After H2 addition, microbial abundance showed an increase in the bacteria and archaea communities in the interstitial matrix. The Thermodesulfobiaceae family (29%)remained dominant in the interstitial matrix, suggesting its crucial role in the immobilized community and the SHA-31 family was enriched in both the effluent (36%) and the interstitial matrix (15%). The predominance of archaea Methanothermobacter thermoautrophicus indicated that CH4 was produced almost exclusively by the hydrogenotrophic pathway.

Metagenomic and bioanalytical insights into quorum sensing of methanogens in anaerobic digestion systems with or without the addition of conductive filter

Understanding microbial interactions in the methanogenesis system through quorum sensing (QS) is very important for system optimization. Known QS genes were collected and classified into seven groups based on the signal molecules, which were used for constructing a hierarchical quorum sensing database (QSDB). QSDB containing 39,981 QS genes of seven QS groups was constructed and QS genes were analyzed with QSDB. Methanogen genomes were aligned with QSDB and acyl-homoserine lactones (AHLs) system was predicted as the most probable QS system. This database was further applied to analyze QS in methanogens from two upflow anaerobic sludge blanket-anaerobic filter hybrid reactors with conductive filter (CFB) and nonconductive filter (SEP), and a control without filter (CON). The maximum COD degradation rates in CFB (722.2 ± 10.1 mg/L·h) was elevated by 42.9% compared to CON (505.4 ± 5.98 mg/L·h). Metagenomic sequencing revealed Methanosaeta, Methanobacterium, and Methanosarcina were dominant, and the abundances was 4.3 times higher in the sludge of CFB compared to CON. The overall abundance of QS genes was CFB > SEP > CON, and AHLs were the most abundant group of QS genes. The filI/filR system, a luxI/luxR homolog, was firstly detected in methanogens, showing a high abundance in the CFB (0.085%) compared to in the CON (0.058%). The concentration of AHL molecules in CFB biofilms (0.04%) was about four times that in the CON (0.01%). Syntrophobacter and Smithella were the two major syntrophic bacteria of methanogens, and their abundances were positively correlated with methanogens. In addition, Syntrophobacter and Smithella harbored QS RpfB (component of the diffusible signal factor system) and PDE (component of cyclic di-GMP system). This study provides useful guidance for deeply understanding of QS in anaerobic digestion systems.

Monte carlo analysis of various geometrical blankets in a fusion-fission hybrid reactor

• A dense plasma focus device design as a fusion neutron source. • Investigate the neutron diffusion equation in the cylindrical layer, the spherical layer and the frustum cone layer geometries. • Investigate the lowest probability of a neutron returning from the second blanket to the first blanket in the cylindrical layer, the spherical layer and the frustum cone layer geometries. • Investigate the neutron parameters in the One-Blanket Reactor and Two-Blanket Reactorand the ultimate energy of the hybrid reactor by MCNPX code. • To check the safety of staff and reactor facilities, the dose rate of neutrons and photons in the concrete shield is calculated by MCNPX code. Fusion - fission hybrid reactor consists of two main parts. The first part is the Dense Plasma Focus (DPF) where the fusion process is performed and the second part is the blankets which surround the DPF and the fission process is done in the blankets. The most of the fusion neutrons, near the fusion source, are directed upward, so the blanket over the DPF is designed in forms cylindrical, spherical and frustum cone of volumes 183,347 cm 3 , 136,378 cm 3 and 58,223.2 cm 3 respectively at the same effective multiplication factor. Then the thermal neutron diffusion equation, buckling and neutron parameters are studied. After selecting the first blanket, the second blanket is designed in forms cylindrical, spherical and frustum cone of volumes 4.500 × 10 6 cm 3 , 3.689 × 10 6 cm 3 and 6.441 × 10 5 cm 3 respectively. So the frustum cone is chosen for the first and second blanket. The neutron return probability in the frustum cone from the second blanket to the first blanket is low, so the first blanket's effective multiplication factor does not change and the reactor's total effective multiplication factor is stable. Also, MCNPX code has been used to checkout and select neutron multiplier and reflector cells for the most neutron yield.