Showing papers in "World Journal of Nuclear Science and Technology in 2021"
TL;DR: In this article, the distribution of radon and its decay inside the shower will be numerically investigated using AlphaGUARD, which is used as an input for CFD simulation.
Abstract: Human exposure to radon inside different parts of the house has become a great concern. In this study, the distribution of radon and its decay inside the shower will be numerically investigated. In fact, the radon concentration in water is measured through the use of AlphaGUARD. They are used as an input for CFD simulation. The numerical results proved that temperature and humidity have significant impacts on both radon content and distribution. Also, the equilibrium factor variations between radon and its progeny with the temperature and relative humidity were carefully looked at. The equivalent doses due to 218Po and 214Po were evaluated in different tissues of the respiratory tract of the members of the public from the inhalation of air inside the shower. The annual effective dose due to radon short lived decay from the inhalation of air inside the shower by the members of the public was also investigated.
2 citations
TL;DR: In this article, the main nuclear reactors concepts, identifying new technological or theoretical developments useful to nuclear field, and analysing how new recombination could affect feasibility of nuclear fusion are enumerated.
Abstract: New research developments suggest that nuclear reactors using fusion may enter the market sooner than imagined even for mobile applications, like merchant ship propulsion and remote power generation. This article aims at pointing such developments and how they could affect nuclear fusion. The method is enumerating the main nuclear reactors concepts, identifying new technological or theoretical developments useful to nuclear field, and analysing how new recombination could affect feasibility of nuclear fusion. New technologies or experimental results do not always work the way people imagine, being better or worse for intended effects or even bringing completely unforeseen effects. Results point the following designs could be successful, in descending order of potential: aneutronic nuclear reactions using lattice confinement, aneutronic nuclear reactions using inertial along magnetic confinement, hybrid fission-lattice confinement fusion, and fission reactions.
2 citations
TL;DR: In this paper, the results of the recent integral effect tests (IETs) with the LSTF were reviewed to experimentally identify thermal-hydraulic phenomena involved, regarding the PWR accident sequences in accordance with the new regulatory requirements for the Japanese light-water nuclear power plants.
Abstract: Many experiments have been conducted on accidents and transients of pressurized water reactor (PWR) employing the rig of safety assessment/large-scale test facility (ROSA/LSTF). Recent research activities concerned with the OECD/NEA international joint projects included experimental investigation via the ROSA and ROSA-2 Projects, and counterpart testing with thermal-hydraulic integral test facilities under collaboration of the PKL-2, PKL-3, ATLAS, and ATLAS-2 Projects. Major results of the related integral effect tests (IETs) with the LSTF were reviewed to experimentally identify thermal-hydraulic phenomena involved, regarding the PWR accident sequences in accordance with the new regulatory requirements for the Japanese light-water nuclear power plants. Future separate effect test using the LSTF is planned to simulate loss of emergency core cooling system (ECCS) recirculation functions in a large-break loss-of-coolant accident (LOCA). Key results of the recent IETs utilizing the LSTF and future plans were presented relevant to multiple steam generator tube rupture accident with recovery operation, small-break LOCA with accident management measure on core exit temperature reliability, and small-break LOCA with thermal stratification under cold water injection from ECCS into cold legs. Also, main outcomes of the LSTF IETs were indicated for wide spectrum LOCA with core uncovery and anticipated transient without scram following small-break LOCA under totally failed high-pressure injection system.
TL;DR: In this paper, the helium bubble coalescence in titanium with dislocations was simulated using molecular dynamics method and the results showed that when the second helium bubble nucleates near the slip plane, it grows toward the first helium bubble which lies at the dislocation core till they coalesce with each other.
Abstract: Dislocation and grain boundary have great influence on helium behavior in materials. In this paper, the helium bubble coalescence in titanium with dislocations was simulated using molecular dynamics method. The results show that, when the second helium bubble nucleates near the slip plane, it grows toward the first helium bubble which lies at the dislocation core till they coalesce with each other. However, it is not easy for the coalescence to occur if the two helium bubbles lie in different atomic layers in (001) plane. If the second helium bubble is nucleated on the side of the slip plane with full atomic layers, the second helium bubble growth could lead to the movement of the first helium bubble toward the other sides of the slip plane. The growth rate and direction of the second helium bubble are closely related to the pressure around it.
TL;DR: In this article, the use of a fast thorium-cycle ADS with liquid lead-bismuth eutectic coolant for the production of molybdenum-99/technetium-99m and lutetium177 was examined.
Abstract: Radiopharmaceuticals are used in nuclear medicine for diagnostic or therapeutic acts. The short decay half-lives of medical radioisotopes, especially those used for diagnostics, imply that they should be produced continuously and transported as quickly as possible to the medical units where they are used. Neutron-rich medical radioisotopes are generally produced in research reactors, like technetium-99m, lutetium-177, holmium-166 and iodine-131. On the other hand, proton-rich radioisotopes are produced via reactions with charged particles from accelerators like fluorine-18, gallium-67, iodine-123 and thallium-201. Beside this, innovative nuclear reactors are advocated as solutions to the issues of nuclear waste production and proliferation threats. Fast neutron, thorium-cycle and accelerator-driven subcritical (ADS) reactors are some of the most promising of them, proposed as safer fuel breeders and “waste burners”. This article examines the use of a fast thorium-cycle ADS with liquid lead-bismuth eutectic coolant for the production of molybdenum-99/technetium-99m and lutetium-177. Burnup simulation has been made with the Monte-Carlo (MC) code SERPENT. It is demonstrated that MC codes can advantageously be used to determine the optimal irradiation time for a given radioisotope in a realistic reactor core. It is also shown that fast thorium-cycle ADS is an economical option for the production of medical radioisotopes.
TL;DR: In this article, the annealing of damaged high purity germanium detectors has been investigated and the experiment results indicate that raising the temperature to 70°C for five days, the restoration efficiency can reach 90%.
Abstract: High purity germanium detectors have important applications in many fields. Detector’s performance deteriorated significantly due to radiation of neutron. The annealing of damaged HPGe detector is expounded in this monograph. The experiment results indicate that raising the temperature to 70°C for five days, the restoration efficiency can reach 90%.
TL;DR: By comparing the DRL of the work to theDRL values obtained in other countries, it can be said that efforts can be made to further protect patients from unnecessary doses.
Abstract: Objective: The aim of our work is to study radiological practices in C?te d’Ivoire regarding the examination of the frontal chest in order to optimize the dose received by patients. Materials and Methods: The work was carried out in 11 of the most frequented radiology centers and involved 330 patients. The equipment used in addition to those that can be found in an X-ray room is the DAP-meter. Using the DAP-meter, we measured the Dose in the air (Dair) then we calculated the Entrance Surface Dose (De). Results: We have by the statistical method of the 75th percentile determined the Diagnostic Reference Level (DRL): 0.28 ± 0.03 mGy and by the arithmetic average, the average of the entrance surface dose (Dem): 0.23 ± 0.03 mGy. Since the DRL is lower than the Dem, the dose is said to be optimized. However by comparing the DRL of our work to the DRL values obtained in other countries, we can say that efforts can be made to further protect patients from unnecessary doses. This involves increasing the voltage, decreasing the load, increasing the detector focal point distance, and increasing additional filtration.