Xenotransplantation is a promising strategy to alleviate the shortage of organs for human transplantation. In addition to the concerns about pig-to-human immunological compatibility, the risk of ...cross-species transmission of porcine endogenous retroviruses (PERVs) has impeded the clinical application of this approach. We previously demonstrated the feasibility of inactivating PERV activity in an immortalized pig cell line. We now confirm that PERVs infect human cells, and we observe the horizontal transfer of PERVs among human cells. Using CRISPR-Cas9, we inactivated all of the PERVs in a porcine primary cell line and generated PERV-inactivated pigs via somatic cell nuclear transfer. Our study highlights the value of PERV inactivation to prevent cross-species viral transmission and demonstrates the successful production of PERV-inactivated animals to address the safety concern in clinical xenotransplantation.
In order to compare the ENDF/B-VIII.0 and CENDL-3.2 Fe-56 nuclear data, twenty-nine iron sensitive models were selected from the International Criticality Safety Benchmarking Experiments Evaluation ...Project(ICSBEP), including twenty-one highly enriched uranium models and eight plutonium metal models.The benchmark models were modeled in MC program and
k
eff
were calculated with complete ENDF/B-VIII.0, and with hybrid ENDF/B-VIII.0 with CENDL-3.2 Fe-56 substituted, respectively. For most models, the benchmarking criticality calculation results show that with hybrid ENDF/B-VIII.0 there are 381 pcm or less reduction in
k
eff
, compared with complete ENDF/B-VIII.0. Besides, it shows improved agreement for plutonium metal models and a little worsened agreement for highly enriched uranium models with hybrid ENDF/B-VIII.0.
Different technologies produce hydrogen with varying cost and carbon footprints over the entire resource supply chain and manufacturing steps. This paper examines the relative costs of carbon ...mitigation from a life cycle perspective for 12 different hydrogen production techniques using fossil fuels, nuclear energy and renewable sources by technology substitution. Production costs and life cycle emissions are parameterized and re-estimated from currently available assessments to produce robust ranges to describe uncertainties for each technology. Hydrogen production routes are then compared using a combination of metrics, levelized cost of carbon mitigation and the proportional decarbonization benchmarked against steam methane reforming, to provide a clearer picture of the relative merits of various hydrogen production pathways, the limitations of technologies and the research challenges that need to be addressed for cost-effective decarbonization pathways. The results show that there is a trade-off between the cost of mitigation and the proportion of decarbonization achieved. The most cost-effective methods of decarbonization still utilize fossil feedstocks due to their low cost of extraction and processing, but only offer moderate decarbonisation levels due to previous underestimations of supply chain emissions contributions. Methane pyrolysis may be the most cost-effective short-term abatement solution, but its emissions reduction performance is heavily dependent on managing supply chain emissions whilst cost effectiveness is governed by the price of solid carbon. Renewable electrolytic routes offer significantly higher emissions reductions, but production routes are more complex than those that utilise naturally-occurring energy-dense fuels and hydrogen costs are high at modest renewable energy capacity factors. Nuclear routes are highly cost-effective mitigation options, but could suffer from regionally varied perceptions of safety and concerns regarding proliferation and the available data lacks depth and transparency. Better-performing fossil-based hydrogen production technologies with lower decarbonization fractions will be required to minimise the total cost of decarbonization but may not be commensurate with ambitious climate targets.
Gamma ray is an energetic ionising radiation that can damage living cells as it slows down and transfers its energy to surrounding cells. Lead and concrete have been used as radiation shielding ...materials. However, it shows that lead toxicity is an important environmental disease and its effects on the human body are devastating. Thus, there is an urgent need to find a sustainable radiation shielding material to safeguard the human and the environment from destructive impact of radiation. High atomic number and high-density materials such as tungsten and concrete are the best effective characteristics of radiation shielding materials. There are numerous experimental and theoretical works were performed on radiation shielding materials. This paper presents a review on the application of lead as radiation shielding material, current safety issues related to lead, current work on radiation shielding material and recent development of new lead-free shielding materials in nuclear medicine.
•Lead has been used as a radiation shielding material for radiation protection.•However, lead introduces insidious hazard to human health due to formation of dust particles that affect biochemical systems.•New lead-free materials can replace lead for radiation protection in nuclear medicine.•Recent development of new lead-free radiation shielding materials in nuclear medicine.
Abstract
Ensuring nuclear safety has become of great significance as nuclear power is playing an increasingly important role in supplying worldwide electricity. β-ray monitoring is a crucial method, ...but commercial organic scintillators for β-ray detection suffer from high temperature failure and irradiation damage. Here, we report a type of β-ray scintillator with good thermotolerance and irradiation hardness based on a two-dimensional halide perovskite. Comprehensive composition engineering and doping are carried out with the rationale elaborated. Consequently, effective β-ray scintillation is obtained, the scintillator shows satisfactory thermal quenching and high decomposition temperature, no functionality decay or hysteresis is observed after an accumulated radiation dose of 10 kGy (dose rate 0.67 kGy h
−1
). Besides, the two-dimensional halide perovskite β-ray scintillator also overcomes the notorious intrinsic water instability, and benefits from low-cost aqueous synthesis along with superior waterproofness, thus paving the way towards practical application.
Supercritical carbon dioxide (S-CO2) Brayton cycle has many advantages including high power conversion efficiency at mediate temperature, compact configuration, high system simplicity and low ...efficiency loss using dry cooling, which make it well suited to nuclear reactor applications. S-CO2 power cycle can be used as power conversion system for almost all the nuclear power systems including small modular reactor (SMR), Generation IV reactor and fusion reactor. It can also be used as a self-propellant and self-sustaining decay heat removal system to enhance the safety of existing commercial nuclear power plant. An update of research activities is needed to identify the unique research interests and challenges of S-CO2 power cycle based nuclear applications. This paper is a review of the research activities which have been carried out for S-CO2 power cycle based nuclear applications worldwide. The characteristics of S-CO2 power cycle are presented first to explain the distinctive features of this power cycle. Then the progresses in the experimental study of integrated S-CO2 Brayton cycle test loops are reviewed comprehensively to shed a light on its technical maturity in laboratory. Moreover, a review of various research areas concerning S-CO2 power cycle working as power conversion system or heat removal system for nuclear applications are carried out.
Based on these review works, the challenges and perspectives are discussed and highlighted in the paper. Conclusions can be achieved that S-CO2 Brayton cycle is a promising option to broaden nuclear energy’s application scope.
The number of studies on the capture of radioactive iodine compounds by porous sorbents has regained major importance in the last few years. In fact, nuclear energy is facing major issues related to ...operational safety and the treatment and safe disposal of generated radioactive waste. In particular during nuclear accidents, such as that in 2011 at Fukushima, gaseous radionuclides have been released in the off-gas stream. Among these, radionuclides that are highly volatile and harmful to health such as long-lived
I, short-lived
I and organic compounds such as methyl iodide (CH
I) have been released. Immediate and effective means of capturing and storing these radionuclides are needed. In the present review, we focus on porous sorbents for the capture and storage of radioactive iodine compounds. Concerns with, and limitations of, the existing sorbents with respect to operating conditions and their capacities for iodine capture are discussed and compared.
Our modern society requires environmentally friendly solutions for energy production. Energy can be released not only from the ssion of heavy nuclei but also from the fusion of light nuclei. Nuclear ...fusion is an important option for a clean and safe solution for our long-term energy needs. The extremely high temperatures required for the fusion reaction are routinely realized in several magnetic-fusion machines. Since the early 1990s, up to 16 MW of fusion power has been released in pulses of a few seconds, corresponding to a power multiplication close to break-even. Our understanding of the very complex behaviour of a magnetized plasma at temperatures between 150 and 200 million C surrounded by cold walls has also advanced substantially. This steady progress has resulted in the construction of ITER, a fusion device with a planned fusion power output of 500 MW in pulses of 400 s. ITER should provide answers to remaining important questions on the integration of physics and technology, through a full-size demonstration of a tenfold power multiplication, and on nuclear safety aspects. Here we review the basic physics underlying magnetic fusion: past achievements, present eorts and the prospects for future production of electrical energy. We also discuss questions related to the safety, waste management and decommissioning of a future fusion power plant.
Uranium is the main element for nuclear energy production and is one of the most hazardous radionuclides; its effective enrichment plays a key role in energy strategy and environmental safety. ...Oxime-functionalized nanostructures are the most promising candidates for uranium adsorption. However, current methods for their preparation mainly focus on multistep grafting and oximation processes, and the nanostructures usually show low efficiency. Here, we report a rapid one-step process to synthesize salicylaldoxime/polydopamine modified reduced graphene oxide (RGO-PDA/oxime) via the polymerization of dopamine (DA) and simultaneous deposition of oxime with an obviously decreased total synthesis time of 2 h. The obtained maximum uranium adsorption capacity of up to 1049 mg g −1 was 3–16 times larger than those of the reported single PDA or oxime modified nanostructures. The RGO-PDA/oxime followed the pseudo-second-order kinetics model and Langmuir isotherm equation with much higher adsorption selectivity and recyclability. The outstanding sorption performance is attributed to the electrostatic repulsion between GO and salicylaldoxime and the effective combination between PDA and oxime molecules. Finally, given the adhesion capability of DA to diverse surfaces, this rapid one-step method was used to prepare five other oxime/PDA modified materials, which also showed improved uranium adsorption efficiency. These findings provide a way to obtain oxime-functionalized nanostructures with promising uranium adsorption efficiency.
Titanium alloys play a vital role in optimizing the effectiveness and security of nuclear reactors, strengthening structural durability, and facilitating the effective handling of nuclear waste. The ...aim of this study is to investigate the gamma-ray, neutron, and transmission properties of four common titanium alloys through the examination of the deposited energy amount in the liquid sodium coolant material, in relation to the mechanical properties of these alloys. MCNP (version 6.3) is utilized for designing the titanium pipes. Next, the pipes were re-designed considering the elemental mass fractions and densities of the investigated titanium alloys. Grade 26 sample is reported with the highest values of mass attenuation coefficients and the lowest HVL values among those investigated alloys. Grade 26 is reported to have the lowest TF value, whereas Grade 12 demonstrated the highest TF value. The highest Effective Removal Cross Section (ΣR, 1/cm) value against fast neutrons is reported for Grade 26. The utilization of Grade 26 sample as pipe material resulted in the lowest deposited energy amount (MeV/g) and subsequent lowest contamination in the coolant material. Out of the alloys that were chosen for analysis, it has been determined that Grade 26 exhibits the highest level of strength. It can be concluded that the Grade 26 alloy exhibits desirable characteristics for applications in nuclear technologies that require superior gamma-ray and neutron absorption properties, as well as exceptional mechanical properties. Nevertheless, it is essential to emphasize the importance for ongoing studies to enhance the existing material properties of Grade 26, with the aim of achieving improved safety and efficacy in nuclear applications.
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