High Transmutation Rate Research Articles

The diagnostic accuracy of currently available laboratory tests compared to PCR test for COVID-19: a systematic review and meta-analysis

Coronavirus disease (COVID-19) is caused by SARS-COV-2 and represents the causative agent of a potentially fatal and pandemic viral disease that is of great global public health concern and high transmutation rate and mechanisms. A comprehensive systematic search was performed on PubMed, Scopus, Web of Science, and Google Scholar, to find articles published until March 30, 2020. All relevant articles that reported clinical characteristics and laboratory result information of hospitalized COVID-19 patients were included in the analysis. Based on our analysis, however, articles not used RT-PCR and CT as were excluded all of the randomized controlled trial (RCT) were homogeneous (I2=94.58% and p≤0.001) statistical tests showed no publication bias/small study effect. Accordingly, the result of meta-analysis illustrated that RT-PCR increased cases of laboratory confirmation by more than 99% (95% CI: -1.3.0; 4.74) than other laboratory tests. As a result, this finding, is recommended to pilot and scale-up well and accurate laboratory techniques is used in developing countries, and is essential to prevent and control the pandemic diseases with spread in the world. However, it is recommended to further investigate the adverse effects of Real-time reverse transcriptase polymerase chain reaction (RT-PCR) before fully implementing the confirmation.

Comparative Study on the Impact of endf/b-vii.1 Nuclear Library Uncertainty on the CERCER and CERMET Fueled Accelerator-Driven System Calculation Results Using Monte Carlo Method Codes

Abstract A new design of a small power accelerator-driven system (ADS) using inert matrix fuel—ceramic–ceramic matrix (CERCER) and ceramic-metallic matrix (CERMET) was proposed in our previous work for high transmutation rate, small reactivity loss due to burnup, and enhanced safety features. The fast neutron spectrum in the ADS showed a benefit for reducing minor actinides inventories in the fuel cycle. However, the reliability of the nuclear cross section data of evaluated libraries, especially at high energy, needs to be investigated and its impact on CERCER and CERMET fueled ADS calculation results needs to be assessed. In this study, the impact of endf/b-vii.1 nuclear library uncertainty on the CERCER and CERMET fueled ADS reactivity calculation are evaluated using the Monte Carlo method (scale6.2 and whisper-1.1). The sensitivity coefficients and uncertainty obtained by the two codes show a good agreement. The results reveal the uncertainty of the endf/b-vii.1 nuclear data caused significant uncertainty in the reactivity calculations (about 1000 pcm) and it is particularly higher in the CERMET fueled core due to a harder neutron spectrum. The paper identifies the major contributes—isotopes and related cross sections—to the core reactivity uncertainty by suggesting the enhancement of these nuclear data.

Neutronics study on small power ADS loaded with recycled inert matrix fuel for transuranic elements transmutation using Serpent code

A small power ADS design using thorium oxide and diluent matrix reprocessed fuel is proposed for a high transmutation rate, small reactivity swing, and strong safety features. Two fuel matrices (CERCER and CERMET) and different recycled fuel compositions recovered from UO2 spent fuels with 45 GWd/tU and 60 GWd/tU burnup were investigated to determine the suitable fuel for the ADS. It was found that the transmutation of each isotope depends on TRU initial loading amount. After examining the cores, the results show that CERCER fueled ADS has a negative coolant void reactivity (CVR) and a smaller radiotoxicity at discharge compared to that of CERMET core. It implies that CERCER fuel has enhanced safety features and more flavor in terms of radiotoxicity management. To increase fuel utilization and core operation efficiency, a simple assembly shuffling pattern for the CERCER fueled ADS is also proposed. Eigenvalue and burnup calculations were conducted using Serpent 2 with ENDF/B-VII.0 library in both kcode and external source modes, and it indicates that the results of transmutation analyses obtained by kcode only is reliable to discuss the transmutation potential of ADS. Burnup calculation with the fixed-source mode is essential to be used for more practical results of the transmutation by ADS.

Study on method to achieve high transmutation of LLFP using fast reactor

The purpose of this study is to clarify the method to achieve high transmutation rates of four long-lived fission products (79Se, 99Tc, 107Pd, and 129I) using a fast reactor. New LLFP target assemblies were invented in consideration of the suppression of thermal spikes in adjacent fuel assemblies by combining YD2 and YH2 moderators or using a thermal neutron filter material. It was clarified that the high transmutation rate of about 8%/year was achieved, if the new LLFP target assemblies of 4 nuclides were loaded in the blanket region of the sodium cooled, MOX fueled fast reactor. The feasibility of the LLFP transmutation target was clarified through experiments on material properties and fabrication of the LLFP target, YH2 and YD2 moderators.

Preliminary studies of a new accelerator-driven minor actinide burner in industrial scale

Pursuing high transmutation rate of minor actinide (MA), a preliminary conceptual design of a lead-bismuth (LBE) cooled accelerator-driven system (ADS) is proposed in this study. Parametric studies are performed to optimize the neutronics and thermal–hydraulics performances. The proton energy and axial position of the proton beam impact is investigated to obtain high neutron source efficiency and spallation neutron yield. The influences of MA/Pu mixing ratio and the ratio of pin pitch to diameter (P/D) are also optimized to control the burnup reactivity swing and the minimum coolant velocity for adequate cooling. To reduce the power peak, three kinds of power flattening techniques are adopted and compared. The results show that the inert matrix ratio zone loading method seems more versatile. Based on the analyses, an optimized three zone loading pattern is proposed for the 800MWth subcritical core. The total transmutation rate of MA is 328.8kg per effective full power year. Preliminary safety analyses based on the balance of power method (BOP) are performed and the results show that in the reactivity insertion and beam overpower transients, the core shows inherent safety, but the scram is necessary by cutting off the beam current to protect the core from possible damages caused by the loss of flow.

MYRRHA: A multipurpose nuclear research facility

MYRRHA (Multi-purpose hYbrid Research Reactor for High-tech Applications) is a multipurpose research facility currently being developed at SCK•CEN. MYRRHA is based on the ADS (Accelerator Driven System) concept where a proton accelerator, a spallation target and a subcritical reactor are coupled. MYRRHA will demonstrate the ADS full concept by coupling these three components at a reasonable power level to allow operation feedback.As a flexible irradiation facility, the MYRRHA research facility will be able to work in both critical as subcritical modes. In this way, MYRRHA will allow fuel developments for innovative reactor systems, material developments for GEN IV and fusion reactors, and radioisotope production for medical and industrial applications. MYRRHA will be cooled by lead-bismuth eutectic and will play an important role in the development of the Pb-alloys technology needed for the LFR (Lead Fast Reactor) GEN IV concept. MYRRHA will also contribute to the study of partitioning and transmutation of high-level waste. Transmutation of minor actinides (MA) can be completed in an efficient way in fast neutron spectrum facilities, so both critical reactors and subcritical ADS are potential candidates as dedicated transmutation systems. However critical reactors heavily loaded with fuel containing large amounts of MA pose reactivity control problems, and thus safety problems. A subcritical ADS operates in a flexible and safe manner, even with a core loading containing a high amount of MA leading to a high transmutation rate. In this paper, the most recent developments in the design of the MYRRHA facility are presented.

Determining the americium transmutation rate and fission rate by post-irradiation examination within the scope of the ECRIX-H experiment

The ECRIX-H experiment aims to assess the feasibility of transmuting americium micro-dispersed in an inert magnesia matrix under a locally moderated neutron flux in the Phénix reactor. A first set of examinations demonstrated that pellet behaviour was satisfactory with moderate swelling at the end of the irradiation. Additional post-irradiation examinations needed to be conducted to confirm the high transmutation rate so as to definitively conclude on the success of the ECRIX-H experiment. This article presents and discusses the results of these new examinations. They confirm the satisfactory behaviour of the MgO matrix not only during the basic irradiation but also during post-irradiation thermal transients. These examinations also provide additional information on the behaviour of fission products both in the americium-based particles and in the MgO matrix. These results particularly validate the transmutation rate predicted by the calculation codes using several different analytical techniques. The fission rate is also determined.

Swelling under irradiation of MgO pellets containing americium oxide: The ECRIX-H irradiation experiment

The ECRIX-H irradiation experiment studied the behaviour of pellets containing americium dispersed in MgO. The purpose of the irradiation was to demonstrate the capacity of magnesia to provide an efficient support matrix. After fabrication, the sintered pellets contained 16.65 wt.% of Am microdispersed in the inert matrix. The ECRIX-H pellets were irradiated under a locally moderated neutron flux in the Phénix sodium-cooled fast reactor (SFR) for 318 Effective Full Power Days (EFPD). Post-test calculations indicated that the fission and transmutation rates of americium at the maximum flux plane reached 33.9% and 92.6% respectively at the end of the irradiation phase. The results of the post-irradiation examinations – both non-destructive and destructive – are discussed in this paper. These results indicate a satisfactory behaviour of the MgO matrix. Particularly, a moderate swelling occurs in the pellets under irradiation even with significant quantities of helium generated and at high transmutation rate.

Promise and challenges of SiC f/SiC composites for fusion energy applications

Silicon carbide fiber/silicon carbide matrix composites have been specified in several recent fusion power plant design studies because of their high operating temperature (1000–1100 °C) and hence high energy conversion efficiencies. Radiation resistance of the β-phase of SiC, excellent high-temperature fracture, creep, corrosion and thermal shock resistance and safety advantages arising from low induced radioactivity and afterheat are all positive attributes favoring the selection of SiC f/SiC composites. With the promise of these materials comes a number of challenges such as their thermal conductivity, radiation stability, gaseous transmutation rates, hermetic behavior and joining technology. Recent advances have been made in understanding radiation damage in SiC at the fundamental level through MD simulations of displacement cascades. Radiation stability of composites made with the advanced fibers of Nicalon Type S and the UBE Tyranno SA, where no change in strength was observed up to 10 dpa at 800 °C, in the development of materials with improved thermal conductivity, modeling of thermal conductivity, joining techniques and models for life-prediction. High transmutation rates of C and Si to form H, He, Mg, and Al continue to be a concern.

High level radio-active wastes reduction through fast reactor

The objective of this work is to investigate the characteristics and performance of some dedicated reactor core concepts in terms of the minor actinides (MA) and I-129 transmutation for reducing high level radio-active wastes. Reducing high level radio-active wastes is defined in this paper as follows; The radio-toxicity of long lived radioactive nuclides is reduced by transmutation of MA and I-129 in core. The volume of container for high level radio-active wastes is reduced. I-129 is transmuted because it is easy to solve in underground water and needs additional barrier to confine. Sr-90 and Cs-137 are stored in the facility to decay naturally before disposal. In the reference core arrangement of this study, MA are transmuted in core and I-129 is transmuted around the active core. The following three items on MA transmutation are investigated: the arrangement of MA, Pu and U in core with the negative Doppler constant and high transmutation rate, the application for Pu and MA from Mixed Oxide (MOX) spent fuel from LWR, and the comparison of core type and fuel types. As for I-129 transmutation, the application of moderator to enhance I-129 transmutation rate, the comparison of core type and the scenario of transmutation through irradiation are discussed.

Transmutation of Minor Actinide in Well Thermalized Neutron Field and Application of Advanced Neutron Source(ANS).

Transmutation of Minor Actinide (MA) in a well thermalized neutron field was studied. Since MA nuclides have large effective cross sections in the well thermalized neutron field, the transmutation in the well thermalized neutron field has an advantage of high transmutation rate. However, the transmutation rate largely decreases by accumulation of 246Cm when MA is transmuted only in the well thermalized neutron field for a long period. An acceleration method of burn-up of 246Cm was studied. High transmutation rate can be obtained by providing a neutron field with high flux in the energy region between 1 and 100eV. Two stage transmutation using the well thermalized neutron field and this field can transmute MA rapidly. The applicability of the Advanced Neutron Source (ANS) to the transmutation of MA was examined for a typical MA with the composition in the high-level waste generated in the conventional PWR. If the ANS is applied without changing the fuel inventory, the amount of MA which corresponds to that...

Transmutation of Minor Actinide in Well Thermalized Neutron Field and Application of Advanced Neutron Source (ANS)

Transmutation of Minor Actinide (MA) in a well thermalized neutron field was studied. Since MA nuclides have large effective cross sections in the well thermalized neutron field, the transmutation in the well thermalized neutron field has an advantage of high transmutation rate. However, the transmutation rate largely decreases by accumulation of 246Cm when MA is transmuted only in the well thermalized neutron field for a long period. An acceleration method of burn-up of 246Cm was studied. High transmutation rate can be obtained by providing a neutron field with high flux in the energy region between 1 and 100eV. Two stage transmutation using the well thermalized neutron field and this field can transmute MA rapidly. The applicability of the Advanced Neutron Source (ANS) to the transmutation of MA was examined for a typical MA with the composition in the high-level waste generated in the conventional PWR. If the ANS is applied without changing the fuel inventory, the amount of MA which corresponds to that produced by a conventional 1,175 MWe PWR in one year can be transmuted by the ANS in one year. Furthermore, the amount of the residual can be reduced to about 1g (10−5 of the initial MA weight) by continuing the transmutation for 5 years owing to the two stage transmutation.

Transmutation of Mo, Re, W, Hf, and V in various irradiation test facilities and STARFIRE

With the exception of V and Cu alloys, the formation of solid transmutants has not been thought to play a large role in the response of metals to irradiation. For a number of refractory elements, however, it appears that very large levels of solid transmutation can occur both in fission and fusion spectra. The phase stability and other properties of alloys can be strong functions of the changing composition. The spectral sensitivity of transmutation also poses some difficulty in correlating data from various neutron spectra. Transmutation of Mo, Re, W, Hf and V have been calculated for the Fast Flux Test Facility (FFTF), the High Flux Isotope Reactor (HFIR), and the STARFIRE fusion reactor. Results show that Re and W undergo sizeable transmutation in these spectra, and may limit the use of these elements in fusion reactor materials. Vanadium and hafnium have high transmutation rates in HFIR and may require spectral tailoring.

Transmutation of90Sr by Inertial Confinement Fusion

Transmutation of 90Sr by inertial confinement fusion is discussed. A pellet composed of deuteriumtritium fuel surrounded by 90Sr is compressed by a laser or a particle beam. It is shown that a high transmutation rate and a small transmutation energy are obtained because of the highly compressed 90Sr, which has a large probability of a transmutation reaction. The number of cycles, including recovering and refabrication of the target, is also discussed.

A Neutronic Assessment of Strontium-90 Transmutation in Fusion Reactors

Transmutation of /sup 90/Sr using fusion neutrons has been suggested as a possible technique for disposing of this waste nuclide. For transmutation to be attractive, high transmutation rates relative to natural decay are required. Effective half-lives for /sup 90/Sr were computed for fusion reactor blankets constructed of various materials. To obtain satisfactory transmutation rates, fusion reactors with high first wall neutron currents and with highly moderating blankets were found to be necessary. An effective half-life for /sup 90/Sr of <5 y was extremely difficult to achieve with the fusion concepts and blankets studied. A waste management system was formulated to determine the reduction in the /sup 90/Sr inventory and the number of burners required for various fission usage scenarios. Efficient and fast chemical separations were needed to reap the benefits of a short effective half-life. For the fusion burners considered, it was found that the /sup 90/Sr inventory could not be reduced to less than one-fourth of the inventory without transmutation if fission usage continued at a constant rate. Such a reduction is not sufficient to justify the transmutation disposal of /sup 90/Sr.