Reduction Of Radioactive Waste Research Articles

An enhanced CRADIS decision model for optimizing radioactive waste reduction through transmutations based on Disc Spherical Fuzzy information

Radioactive waste reduction through transmutation techniques is significant for mitigating environmental risks and ensuring long-term safety. It offers a sustainable approach to minimizing the volume of radioactive waste, contributing to both environmental preservation and enhanced nuclear energy sustainability. This paper introduces an extension of aggregation operations to hybrid operators in Disc Spherical Fuzzy Sets (D-SFSs), including D-SFS algebraic hybrid weighted averaging and D-SFS hybrid geometric aggregation operators. These novel operators are tailored for D-SFSs and are supported by rigorous proofs, enhancing their theoretical robustness. Additionally, a Maximum Deviation Method (MDM) is developed in conjunction with a proposed distance measure to assess attribute weights in Multiple Attribute Decision-Making (MADM) problems with Disc Spherical Fuzzy (D-SF) information. The study proposes a new MADM method in the D-SF environment, leveraging the D-SF distance measure and the Compromise Ranking of Alternatives from Distance to Ideal Solution (CRADIS) method. Notably, the paper focuses on extending D-SFs to the CRADIS method, particularly when weight information is entirely unknown. A comprehensive case study on optimizing radioactive waste volume reduction through transmutation technologies is provided. A comparative analysis with existing decision-making methods validates the improved MADM method’s validity and practicality.

Self-cleaning and regenerable nano zero-valent iron modified PCN-224 heterojunction for photo-enhanced radioactive waste reduction.

The expansion of large-scale nuclear power causes a substantial volume of radioactive wastewater containing uranium to be released into the environment. Because of uranium's toxicity and bioaccumulation, it is critical to develop the efficient and sustainable materials for selective removal of uranium (VI). Herein, a regenerable anti-biofouling nano zero-valent iron doped porphyrinic zirconium metal-organic framework (NZVI@PCN-224) heterojunction system was successfully fabricated. Due to the Schottky-junction effect at the NZVI/MOF interface, the NZVI nanomaterial immobilized on PCN-224 could improve interfacial electron transfer and separation efficiency, and enhance entire reduction of highly soluble U(VI) to less soluble U(IV), involving photocatalytic reduction and chemical reduction. Meanwhile, the photocatalytic effect also prompts the NZVI@PCN-224 to produce more biotoxic reactive oxygen species (ROS), resulting in high anti-microbial and anti-algae activities. Under dark conditions, NZVI@PCN-224 with a large specific surface area could provide sufficient oxo atoms as the uranium binding sites and show the highest uranium-adsorbing capability of 57.94mg/g at pH 4.0. After eight adsorption-desorption cycles, NZVI@PCN-224 still retained a high uranium adsorption capacity of 47.98mg/g and elimination efficiency (91.72%). This sorption/reduction/anti-biofouling synergistic strategy of combining chelation, chemical reduction and photocatalytic performance inspires new insights for highly efficient treatment of liquid radioactive waste.

Study on the Reduction of Radioactive Wastes on the Wire Using Blasting Gun Process

Study on the Reduction of Radioactive Wastes on the Wire Using Blasting Gun Process

Manufacturing the Equipment for Reduction of Radioactive Wastes on the Wire Using Blasting Gun Process

Manufacturing the Equipment for Reduction of Radioactive Wastes on the Wire Using Blasting Gun Process

Concept of a small fast breeder reactor system capable of transmuting MA and LLFP

The issues of nuclear power systems are the effective use of uranium resources and the reduction of radioactive wastes. Important radioactive wastes are minor actinides (MA : 237Np, 241Am, 243Am, etc.) and long-lived fission products (LLFP : 129I, 99Tc, 79Se, etc.). The purpose of this study was to construct a system that simultaneously achieves the breeding of fissile materials and the transmutation of MA and LLFP using small fast reactors. Transmutation was achieved by loading the innovative Duplex type MA-containing fuel in the core region and the LLFP-containing moderator in the first layer of the radial blanket. Breeding of the entire small fast reactor system was achieved by combining two small fast reactors: one for transmutation and the other for breeding. As a result, it was clarified that in this small fast reactor system, a breeding ratio of approximately 1.03 was obtained, and support ratios (SRs) of 2 or more were achieved for MAs and LLFPs.

Self-Cleaning and Regenerable Nano Zero-Valent Iron Modified Pcn-224 Heterojunction for Photo-Enhanced Radioactive Waste Reduction

Self-Cleaning and Regenerable Nano Zero-Valent Iron Modified Pcn-224 Heterojunction for Photo-Enhanced Radioactive Waste Reduction

Concept of a fast breeder reactor to transmute MAs and LLFPs

The long-term issues of nuclear power systems are the effective use of uranium resources and the reduction of radioactive waste. Important radioactive wastes are minor actinides (MAs: 237Np, 241Am, 243Am, etc.) and long-lived fission products (LLFPs: 129I, 99Tc, 79Se, etc.). The purpose of this study was to show a concept that can simultaneously achieve the breeding of fissile materials and the transmutation of MAs and LLFPs in one fast reactor. Transmutation was carried out by loading innovative Duplex-type MA fuel in the core region and LLFP-containing moderator in the first layer of the radial blanket. Breeding was achieved in the core and axial blanket. As a result, it was clarified that in this fast breeder reactor, a breeding ratio of approximately 1.1 was obtained, and MAs and LLFPs achieved a support ratio of 1 or more. The transmutation rate was 10.3%/y for 237Np, 14.1%/y for 241Am, 9.9%/y for 243Am, 1.6%/y for 129I, 0.75%/y for 99Tc, and 4%/y for 79Se. By simultaneously breeding fissile materials and transmuting MAs and LLFPs in one fast reactor, it will be possible to solve the long-term issues of the nuclear power reactor system, such as securing nuclear fuel resources and reducing radioactive waste.

Use of plasma reactor to viabilise the volumetric reduction of radioactive wastes

Nuclear reactors, hospitals, industries and research institutes generate considerable amounts of radioactive waste every day. To dispose this waste in a safe and cost-effective manner, it must be treated by immobilising the radionuclides and, for better stocking capacity, it must be volumetrically reduced as much as possible. To this end, plasma technology, among other promising technologies for radioactive waste treatment, exposes radioactive waste to temperatures above 1400 °C, thereby substantially reducing its volume. In the planning and managing of radioactive waste, the challenges related to plasma technology are presented as a motivation factor for the possible implantation of plasma reactors in nuclear plants and research centres, thereby improving radioactive waste management. In this study, a thermal plasma treatment process was established, and a plasma reactor was used for compactable waste processing. After 30 min of thermal plasma treatment, the volume reduction factor reached 1:99. The results demonstrate the viability of using a thermal plasma process for the volumetric reduction of radioactive waste in a safe and cost-effective manner.

Understanding of electrochemical behaviors of niobium in molten LiCl–KCl eutectic for pyrochemical decontamination process

In this study, the electrochemical behaviors of niobium were examined with 1.0 wt% of NbCl5 in the molten LiCl–KCl at 450 °C via different electrochemical techniques. A chronoamperometry was performed to prepare solutions containing the selected oxidation state of the Nb ion, and the color of the solution was compared to the literature data. Cyclic voltammetries were performed with a combination of different scan ranges and scan rates using an electrochemical cell prepared by LiCl–KCl–NbCl5 salt mixture and an inert tungsten electrode. Five oxidation and four reduction peaks were found, and possible redox reactions attributing to each peak were identified based on the rate of change of the current density as a function of the scan rate. It was found that Nb(V) can be deposited as a metallic Nb via Nb(IV), Nb(III), and Nb(II), and the deposition of the metallic Nb is perturbed by the formation of insoluble nonstoichiometric Nb chloride compounds on the electrode surface. Three irreversible oxidation peaks were caused by the oxidation of metallic Nb and insoluble Nb chlorides, which competed with each other, but the dissolution of metallic Nb became dominant as the scan rate increased. X-ray diffraction analysis was performed to examine the possibility of a chemical reduction of Nb(V) to Nb(IV), but no evidence was found, which indicated the initial concentration of Nb(V) was preserved in all the experiments. It was also found that the different pyrochemical processes would desirable to separate Nb for the purpose of salt purification as well as volume reduction of radioactive waste, depending on the electrochemical behaviors for other elements that can be simultaneously dissolved with Nb.

Data-Driven Periodic Adjustment of Seed Ordering Strategies Permits Reduction of Radioactive Waste and Cost in LDR Prostate Brachytherapy

Intraoperative LDR prostate brachytherapy requires the availability of a sufficient number of radioactive seeds of appropriate activity to deliver the prescription dose to a given target volume. This number can be estimated with a volume study, but that is inconvenient for patients who travel for the procedure and a strain on clinical resources. Instead, we order seeds based on a diagnostic MRI that often is taken months before the procedure. To make up for the volume estimate uncertainty, an excess of seeds is ordered, resulting in radioactive waste and higher cost. In this work, we describe a knowledge-based system for seed ordering that ensures having enough seeds for all cases, without the use of a volume study while minimizing waste seeds.

Polymeric coatings for surface decontamination and ecofriendly volume reduction of radioactive waste after use

A magnet-sensitive and strippable polymeric coating that consists of a magnetic adsorbent with 137Cs adsorption properties using a polyacrylamide (PAAm)/alginate(Alg)-based hydrogel with highly elastic properties was developed for surface decontamination. The aqueous polymeric solution of PAAm and Alg containing adsorbent could be easily applied to 137Cs-contaminated surfaces via the brush method. The simple addition of calcium ions on the surface induced the formation of an adsorbent/PAAm-Alg hydrogel film that could easily peel away from decontaminated surfaces due to its high elasticity. This polymeric coating displayed a good removal efficiency of 96.53% and a decontamination factor (DF) of 28.85 for 137Cs-contaminated surfaces due to the presence of the adsorbent, which had a large distribution coefficient for Cs (3.34 × 104 mL/g), and the large amount of Cs chelating groups in the Alg and PAAm, such as carboxyl and amine groups. The generated volume of the radioactive wastes after surface decontamination was simply reduced due to the magnetic separation of the adsorbent from the used polymeric coating. Furthermore, this new ecofriendly volume reduction method for radioactive waste demonstrated the reusability of PAAm and Alg for further surface decontamination because almost all of the 137Cs (99.838%) captured in the used polymeric coating was removed by magnetic separation of the adsorbent. Therefore, the adsorbent/PAAm-Alg-based polymeric coating system has excellent potential as a new cost-effective surface decontaminant.

Present Situation of Fukushima and Possibility of Decontamination Technology by Superconducting Magnetic Separation System

SUMMARYA large amount of radionuclides were spread by the accident of Fukushima Daiichi nuclear power plant in 2011. The situation of surrounding area of nuclear power plant is momentarily changing. In order to consider for decontamination or volume reduction of radioactive wastes, it is necessary taking into account not only the technical needs but also feelings of inhabitants, reduction of environmental load, reduction of the radiation exposure on workers, and efficiency and cost of decontamination work. In this paper, the application possibility of superconducting magnetic separation system for decontamination and volume reduction was discussed compared with other technologies from above multidirectional viewpoint.

Innovative Nuclear Power Plant Building Arrangement in Consideration of Decommissioning

Abstract A new concept termed the Innovative Nuclear Power Plant Building Arrangement (INBA) strategy is a new nuclear power plant building arrangement method which encompasses upfront consideration of more efficient decommissioning. Although existing decommissioning strategies such as immediate dismantling and differed dismantling has the advantage of either early site restoration or radioactive decommissioning waste reduction, the INBA strategy has the advantages of both strategies. In this research paper, the concept and the implementation method of the INBA strategy will be described. Two primary benefits will be further described: (1) early site restoration; and (2) radioactive waste reduction. Several other potential benefits will also be identified. For the estimation of economic benefit, the INBA strategy, with two primary benefits, will be compared with the immediate dismantling strategy. The effect of a short life cycle nuclear power plant in combination with the INBA strategy will be reviewed. Finally, some of the major impediments to the realization of this strategy will be discussed.

Reduction of Radioactive Waste from Remediation of Uranium-Contaminated Soil

Great amounts of solid radioactive waste (second waste) and waste solution are generated from the remediation of uranium-contaminated soil. To reduce these, we investigated washing with a less acidic solution and recycling the waste solution after removal of the dominant elements and uranium. Increasing the pH of the washing solution from 0.5 to 1.5 would be beneficial in terms of economics. A high content of calcium in the waste solution was precipitated by adding sulfuric acid. The second waste can be significantly reduced by using sorption and desorption techniques on ampholyte resin S-950 prior to the precipitation of uranium at pH 3.0.

Purification of LiCl–KCl eutectic waste salt containing rare earth chlorides delivered from the pyrochemical process of used nuclear fuel using a reactive distillation process

In the pyrochemical process of used nuclear fuel, the purification of waste salts containing radioactive nuclides can greatly contribute to a radioactive waste reduction. For this reason, the purification of LiCl–KCl eutectic salt containing rare earth chlorides was performed using a series of the phosphorylation process and the distillation process. LiCl–KCl eutectic salt recovered from the purification had a very low concentration (<1 ppm) for the rare earth chlorides. The recycling feasibility of the recovered salt was verified through a uranium electro-deposition test using LiCl–KCl eutectic salt as the electrolyte. Based on these results, one body type of reactive distillation equipment with two top covers was designed.

Reduction of Radioactive Waste Through the Reuse and Recycle Policy of the Sealed Radioactive Sources Management

In the past few years, the utilization of sealed source for medical, industrial and research purposes has shown an accelerating increase. This situation will lead to increases in the amount of sealed radioactive. During its use, a sealed radioactive waste will eventually become either a spent sealed source or disused sealed radioactive source (DSRS), due to certain factors. The reduction of the amount of radioactive waste can be executed through the application of reuse and recycle of sealed source. The reuse and recycle policy for spent and disused sealed sources are not already specified yet. The reuse of spent sealed sources can be applied only for the sources which had been used in the medical field for radiotherapy, namely the reuse of a teletherapy Co-60 source in a calibration facility. The recycle of a spent sealed source can be performed for radioactive sources with relatively high activities and long half-lives; however, the recycling activity may only be performed by the manufacturer. To avoid legal conflicts, in the amendment to the Government Regulation No.27 Year 2002 on Management of Radioactive Waste, there will be a recommendation for a new scheme in the management of radioactive waste to facilitate the application of the principles of reduce, reuse, and recycle. Received: Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 20November 2010 ; Revised: Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 11 June 2012 ; Accepted: 30 August 2012

Application of Sulfide Process to Fuel Debris Treatment

In nuclear reactor accident at Fukushima NPP, the reactor core was damaged by the severe conditions such as very high temperature and sea water injection, forming a huge amount of nuclear fuel waste so called debris fuel. Since UO2 fuel pellets are packed in the zircaloy cladding and the fuel assemblies were charged in the reactor core, the fuel debris consists of many types of the mixture of nuclear fuel and structural materials. Some of them are the mixture of metal and oxide, or mixtures after melting. Sulfurization method is one of the promising techniques for the separation and recovery of rare metals. Especially, the dry process has an advantage for the reduction of radioactive waste in nuclear engineering field. In this paper, sulfuization behavior of uranium oxides, zirconium oxide and metal as fuel and structural materials was studied by using carbon disulfide for the sulfurization treatment of fuel debris components. No reaction was observed for Uranium oxides in the presence of CS2 at T<773K, while metal components, such as zirconium metal shows sulfurization at lower temperature. After the selective sulfurization treatment, separation of sulfurized materials from oxides or metals was examined by acid leaching method. Application of mechanochemical treatment was considered for the size reduction and effective sullfurization. When the mixture of simulated fuel debris was mechanochemically treated, the interaction of zirconium with UO2 seems to occur forming the UO2-ZrO2 solid solution.

ADVANCED SFR DESIGN CONCEPTS AND R&amp;D ACTIVITIES

In order to meet the increasing demand for electricity, Korea has to rely on nuclear energy due to its poor natural resources. In order for nuclear energy to be expanded in its utilization, issues with uranium supply and waste management issues have to be addressed. Fast reactor system is one of the most promising options for electricity generation with its efficient utilization of uranium resources and reduction of radioactive waste, thus contributing to sustainable development. The Korea Atomic Energy Research Institute (KAERI) has been performing R&Ds on Sodium-cooled Fast Reactors (SFRs) under the national nuclear R&D program. Based on the experiences gained from the development of KALIMER conceptual designs of a pool-type U-TRU-10%Zr metal fuel loaded reactor, KAERI is currently developing Advanced SFR design concepts that can better meet the Generation IV technology goals. This also includes developing, Advanced SFR technologies necessary for its commercialization and basic key technologies, aiming at the conceptual design of an Advanced SFR by 2011. KAERI is making R&D efforts to develop advanced design concepts including a passive decay heat removal system and a supercritical <TEX>$CO_2$</TEX> Brayton cycle energy conversion system, as well as developing design methodologies, computational tools, and sodium technology. The long-term Advanced SFR development plan will be carried out toward the construction of an Advanced SFR demonstration plant by 2028.

Synthesis and Characterization of Imprinted Polymers for Radioactive Waste Reduction

A cobalt(II) imprinted polymer, that could lead to significant reduction in radioactive waste volume generated during decontamination of nuclear reactors, was synthesized using [N-(4-vinylbenzyl) imino]diacetic acid as the functional monomer through two different methods. The imprinted polymer was found to selectively trap cobalt(II) ions even when present in ppb levels from strong complexing medium against excess ferrous ions. It showed no uptake of ferrous ions under the conditions tested. Cobalt sorption and desorption were found to be rapid. The cobalt selectivity of the polymer was also demonstrated with radioactive cobaltous ions wherein it showed 55% reduction in cobalt activity from a complexing solution containing 2 μCi of radioactive cobalt along with excess ferrous ions. The selectivity of the polymer was compared to that of a commercial resin containing similar functional ligand.

Measurement and analysis of induced activities in concrete irradiated using high-energy neutrons at KENS neutron spallation source facility

Precise estimation of induced activities in concrete shields for high-energy accelerator facilities is one of the most important issues that need to be solved, not only for the reduction of exposure for workers, but also for the reduction of radioactive wastes. Irradiation experiments have been performed by using the 500 MeV Neutron Spallation Source Facility in KEK. The large concrete assembly was placed in the direction of 0 degrees to the beamline. Two kinds of samples were placed at several positions in the assembly. The irradiation period was about 1 week and induced activities in the samples were measured until approximately 1.5 y after irradiation. From the comparison between the experiment and the available Monte Carlo calculation code system, good agreement was obtained for 24Na, 47Sc, 47Ca and 54Mn within a factor 2; however, large discrepancies were observed for some other nuclides.