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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 397 records · Page 22
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

Description of alpha decay and cluster radioactivity in the dinuclear system model

A unified description of cluster radioactivity and α-decay of cold nuclei in the dinuclear system model is proposed. Quantum dynamical fluctuations along the charge (mass) asymmetry coordinate determine the spectroscopic factor, and tunneling along the relative distance coordinate determines the penetrability of the barrier of the nucleus–nucleus interaction potential. A new method for calculating the spectroscopic factor is proposed. The hindrance factors for the orbital angular momentum transfer are studied. A potential reason for the half-life to deviate from the Geiger–Nuttall law in α-decays of neutron-deficient nuclei {sup 194,} {sup 196}Rn is found. The fine structure of α-decays of U and Th isotopes is predicted and characterized. The model is used to describe α-decays from the rotational band of even–even nuclei. The known half-lives in the regions of “lead” and “tin” radioactivities are reproduced well, and the most probable cluster yields are predicted. The cluster decay of excited nuclei is discussed. The relation of cluster radioactivity to spontaneous fission and highly deformed nuclear states is analyzed.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2012

APPLICATION FO FLOW FORMING FOR USE IN RADIOACTIVE MATERIAL PACKAGING DESIGNS

This paper reports on the development and testing performed to demonstrate the use of flow forming as an alternate method of manufacturing containment vessels for use in radioactive material shipping packaging designs. Additionally, ASME Boiler and Pressure Vessel Code, Section III, Subsection NB compliance along with the benefits compared to typical welding of containment vessels will be discussed. SRNL has completed fabrication development and the testing on flow formed containment vessels to demonstrate the use of flow forming as an alternate method of manufacturing a welded 6-inch diameter containment vessel currently used in the 9975 and 9977 radioactive material shipping packaging. Material testing and nondestructive evaluation of the flow formed parts demonstrate compliance to the minimum material requirements specified in applicable parts of ASME Boiler and Pressure Vessel Code, Section II. Destructive burst testing shows comparable results to that of a welded design. The benefits of flow forming as compared to typical welding of containment vessels are significant: dimensional control is improved due to no weld distortion; less final machining; weld fit-up issues associated with pipes and pipe caps are eliminated; post-weld non-destructive testing (i.e., radiography and die penetrant tests) is not necessary; and less fabrication steps are required. Results presented in this paper indicate some of the benefits in adapting flow forming to design of future radioactive material shipping packages containment vessels.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2013

Implementation of Information Management System for Radiation Safety of Personnel at the Russian Northwest Center for Radioactive Waste Management 'SevRAO' - 13131

The report is an overview of the information-analytical system designed to assure radiation safety of workers. The system was implemented in the Northwest Radioactive Waste Management Center 'SevRAO' (which is a branch of the Federal State Unitary Enterprise 'Radioactive Waste Management Enterprise RosRAO'). The center is located in the Northwest Russia. In respect to 'SevRAO', the Federal Medical-Biological Agency is the regulatory body, which deals with issues of radiation control. The main document to regulate radiation control is 'Reference levels of radiation factors in radioactive wastes management center'. This document contains about 250 parameters. We have developed a software tool to simplify control of these parameters. The software includes: input interface, the database, dose calculating module and analytical block. Input interface is used to enter radiation environment data. Dose calculating module calculates the dose on the route. Analytical block optimizes and analyzes radiation situation maps. Much attention is paid to the GUI and graphical representation of results. The operator can enter the route at the industrial site or watch the fluctuations of the dose rate field on the map. Most of the results are presented in a visual form. Here we present some analytical tasks, such as comparison of the dose rate in some point with control levels at this point, to be solved for the purpose of radiation safety control. The program helps to identify points making the largest contribution to the collective dose of the personnel. The tool can automatically calculate the route with the lowest dose, compare and choose the best route. The program uses several options to visualize the radiation environment at the industrial site. This system will be useful for radiation monitoring services during the operation, planning of works and development of scenarios. The paper presents some applications of this system on real data over three years - from March 2009 to February 2012. (authors)

61 RADIATION PROTECTION AND DOSIMETRY↗
DOE OSTI2016

Synthesis of Bismuth Functionalized Grapheme Oxide for Radioactive Iodine Gas Removal - 16114

Released radioactive iodine from nuclear reactors and nuclear severe accidents, such as those experienced at Chernobyl and Fukushima, is one of the most hazardous materials and can affect human health. Uptake of radioactive iodine from gaseous and aqueous waste, consisting of mainly organic forms such as methyl iodide and elemental iodine after reacting with organic matter in scrubber process, is a recent concern during nuclear power plant operation. In general, Triethylenediamine (TEDA) or KI-impregnated activated carbons, silver-loaded silica aerogels, and silver-loaded zeolite are used to remove radioactive iodine compounds. However, previous research has shown TEDA and KI-impregnated activated carbons to have some limitations for use in responding to severe accidents or in pressurized-water reactors, because they are easily burned up and the iodine removal efficiency of silver-loaded sorbents is greatly decreased at high temperatures. To improve the capability of synthesized sorbent material used in iodine gas removal, highly efficient sorbents for methyl and elemental iodine removal were prepared through the functionalization of graphene oxide (GO) with bismuth. GO was synthesized from natural graphite powder (99.95%) by the modified Hummers method, and then mixed with Bi(NO{sub 3}){sub 3}.5H{sub 2}O. After developing a sorbent for the removal of iodine, the synthesized sorbent was characterized using x-ray diffraction, a scanning electron microscope/energy dispersive spectrometer, and thermogravimetric analysis/differential scanning calorimetry, and the surface area of sorbents was determined using the BET-N{sub 2} adsorption method. Methyl iodine batch experiments were conducted for 7 days and elemental iodine gas adsorption experiments were conducted at high temperature (190 deg. C) using a carrier gas (air). The final concentration of iodine in batch and off-gas scrubber solutions (0.1 M NaOH) was analyzed using inductively coupled plasma mass spectrometry. The breakthrough curve and decontamination factor values were also investigated using bismuth-functionalized GO and the results were compared with Ag-zeolite, Sn-apatite, and activated carbon. (authors)

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2017

Chemical Decontamination Performance of Radioactive Metal Surface Using HyBRID Process

The metal oxides formed on the surface of the primary coolant system of a NPP (Nuclear Power Plant) contain radioactive components, and thus the oxides are generally need to be removed by means of chemical decontamination to reduce the exposure of workers during the decommissioning of a NPP. The commercial application of chemical decontamination technology has expanded significantly in recent years at NPPs. From initial applications to components and small subsystems, to the current examination of full system decontamination, the entire technology has become sophisticated. Dilute chemical decontamination solutions have been developed because too aggressive solution is deemed to cause the undesirable corrosion damage to the base metal as well as generate a large volume of decontamination waste. KAERI (Korea Atomic Energy Research Institute) has been developing a new multi-step chemical decontamination process for the primary coolant system of a NPP. This process does not contain any organic chemicals in decontamination solution. The HyBRID (Hydrazine Based Reductive metal Ion Decontamination) process which contains hydrazine as a strong reductant and cupric ion as a catalyst has been developed to be applied as a reductive decontamination step. Instead of usual NP (Nitric acid Permanganate) process, slightly altered SP (Sulfuric acid Permanganate) process is used as a pre-oxidative decontamination step in conjunction with HyBRID process. The preliminary results have proven the effectiveness of this process for the system decontamination. The present study is concerned with the verification of chemical decontamination efficiency for radioactively contaminated surfaces. Therefore, the decontamination performance of radioactive specimen taken from the commercial NPPs using HyBRID coupled with SP process was investigated.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2018

Reactive transport modelling of a cement backfill for radioactive waste disposal

Cementitious materials are included in many geological disposal facilities for radioactive wastes, including the UK candidate backfill material Nirex Reference Vault Backfill (NRVB). As part of an ongoing programme of work to assess NRVB performance, 1-D reactive-transport models have been constructed to simulate reaction with different illustrative groundwater compositions. Variant cases were also produced to explore the effect of model assumptions on the predicted behaviour of the backfill. Depending on groundwater composition, cement alteration pathways included: carbonation; external sulphate attack; chloride attack; the formation of magnesium-rich solids; and the precipitation of secondary aluminosilicate minerals. In general, the models suggest that the pore space in backfill associated with radioactive waste disposal systems is likely to become clogged (to some degree) over time close to backfill-rock interfaces resulting in a reduction in capacity for solute transport. However, the models do not include all relevant process couplings which is potentially, an area for further work.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2013

Development of integrated radioactive waste packaging and conditioning solutions in the UK

In order to offer a more cost effective, safer and efficient Intermediate Level Waste (ILW) management service, EnergySolutions EU Ltd. and Gesellschaft fur Nuklear-Service mbH (GNS) have been engaged in the development of integrated radioactive waste retrieval, packaging and conditioning solutions in the UK. Recognising the challenges surrounding regulatory endorsement and on-site implementation in particular, this has resulted in an alternative approach to meeting customer, safety regulator and disposability requirements. By working closely with waste producers and the organisation(s) responsible for endorsing radioactive waste management operations in the UK, our proposed solutions are now being implemented. By combining GNS' off-the-shelf, proven Ductile Cast Iron Containers (DCICs) and water removal technologies, with EnergySolutions EU Ltd.'s experience and expertise in waste retrieval, safety case development and disposability submissions, a fully integrated service offering has been developed. This has involved significant effort to overcome technical challenges such as onsite equipment deployment, active commissioning, conditioning success criteria and disposability acceptance. Our experience in developing such integrated solutions has highlighted the importance of working in collaboration with all parties to achieve a successful and viable outcome. Ultimately, the goal is to ensure reliable, safe and effective delivery of waste management solutions. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2013

Incineration of European non-nuclear radioactive waste in the USA

Incineration of dry low level radioactive waste from nuclear stations is a well established process achieving high volume reduction factors to minimise disposal costs and to stabilise residues for disposal. Incineration has also been applied successfully in many European Union member countries to wastes arising from use of radionuclides in medicine, nonnuclear research and industry. However, some nations have preferred to accumulate wastes over many years in decay stores to reduce the radioactive burden at point of processing. After decay and sorting the waste, they then require a safe, industrial scale and affordable processing solution for the large volumes accumulated. This paper reports the regulatory, logistical and technical issues encountered in a programme delivered for Eckert and Ziegler Nuclitec to incinerate safely 100 te of waste collected originally from German research, hospital and industrial centres, applying for the first time a 'burn and return' process model for European waste in the US. The EnergySolutions incinerators at Bear Creek, Oak Ridge, Tennessee, USA routinely incinerate waste arising from the non-nuclear user community. To address the requirement from Germany, EnergySolutions had to run a dedicated campaign to reduce cross-contamination with non-German radionuclides to the practical minimum. The waste itself had to be sampled in a carefully controlled programme to ensure the exacting standards of Bear Creek's license and US emissions laws were maintained. Innovation was required in packaging of the waste to minimise transportation costs, including sea freight. The incineration was inspected on behalf of the German regulator (the BfS) to ensure suitability for return to Germany and disposal. This first 'burn and return' programme has safely completed the incineration phase in February and the arising ash will be returned to Germany presently. The paper reports the main findings and lessons learned on this first of its kind project. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2011

Post-Closure Evaluation of the Area 3 and Area 5 Radioactive Waste Management Sites at the Nevada National Security Site in Support of the Site-Wide Environmental Impact Statement

The post-closure performance of the Area 3 Radioactive Waste Management Site (RWMS) and Area 5 RWMS are evaluated for the Site-Wide Environmental Impact Statement using current performance assessment and composite analysis methods and models. Two alternatives with different future waste volumes and inventories are evaluated. The No Action Alternative evaluates the inventory disposed through fiscal year (FY) 2010 plus an additional 4.5E5 cubic meters (m3) (1.59E7 cubic feet [ft3]) of waste disposed at the Area 5 RWMS. The Expanded Operations Alternative evaluates the FY 2010 inventory plus an additional 1.42E6 m3 (5.03E7 ft3) of waste disposed at the Area 5 RWMS and 4.93E4 m3 (1.74E6 ft3) disposed at the Area 3 RWMS. Both the No Action and Expanded Operations Alternatives have a reasonable expectation of meeting all performance objectives of U.S. Department of Energy Order DOE O 435.1, “Radioactive Waste Management.” No significant difference between the two alternatives was found because the waste concentrations are similar. The performance assessment model assesses radiological risk for residents at the RWMS boundary where risk is more closely related to waste concentration than total waste inventory. Results for the composite analysis also indicate that the dose constraint and dose limit can be met for both alternatives.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2011

Iraq liquid radioactive waste tanks maintenance and monitoring program plan.

The purpose of this report is to develop a project management plan for maintaining and monitoring liquid radioactive waste tanks at Iraq's Al-Tuwaitha Nuclear Research Center. Based on information from several sources, the Al-Tuwaitha site has approximately 30 waste tanks that contain varying amounts of liquid or sludge radioactive waste. All of the tanks have been non-operational for over 20 years and most have limited characterization. The program plan embodied in this document provides guidance on conducting radiological surveys, posting radiation control areas and controlling access, performing tank hazard assessments to remove debris and gain access, and conducting routine tank inspections. This program plan provides general advice on how to sample and characterize tank contents, and how to prioritize tanks for soil sampling and borehole monitoring.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2017

Special Analysis for the Disposal of the INL Waste Associated with the Unirradiated Light Water Breeder Reactor (LWBR) Waste Stream at the Area 5 Radioactive Waste Management Site

This special analysis (SA) evaluates whether the Idaho National Laboratory (INL) Waste Associated with the Unirradiated Light Water Breeder Reactor (LWBR) waste stream (INEL167203QR1, Revision 0) is suitable for shallow land burial (SLB) at the Area 5 Radioactive Waste Management Site (RWMS) on the Nevada National Security Site (NNSS). Disposal of the INL Waste Associated with the Unirradiated LWBR waste meets all U.S. Department of Energy (DOE) Manual DOE M 435.1-1, “Radioactive Waste Management Manual,” Chapter IV, Section P performance objectives (DOE 1999). The INL Waste Associated with the Unirradiated LWBR waste stream is recommended for acceptance with the condition that the total uranium-233 ( 23 3U) inventory be limited to 2.7E13 Bq (7.2E2 Ci).

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2017

Analysis of a Radioactive Release in a Nuclear Waste Disposal Facility

The Waste Isolation Pilot Plant (WIPP) is a 655-meter deep mine near Carlsbad, New Mexico, used to dispose the nation’s defense transuranic waste. Limited airborne radioactivity was released from a container of radioactive waste in WIPP on 14 February, 2014. As designed, a mine ventilation filtration system prevented the large scale release of contamination from the underground. However, isolation dampers leaked, which allowed the release of low levels of contaminants after the event until they were sealed. None of the exposed individuals received any recordable dose. While surface contamination was limited, contamination in the ventilation system and portions of the underground was substantial. High efficiency particulate air (HEPA) filters in the operating ventilation system ensure continued containment during recovery and resumption of disposal operations. However, ventilation flow is restricted since the incident, with all exhaust air directed through the filters. Decontamination and natural fixation by the hygroscopic nature of the salt host rock has reduced the likelihood of further contamination spread. Contamination control and ventilation system operability are crucial for resumption of operations. This article provides an operational assessment and evaluation of these two key areas.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2017

Special Analysis for the Disposal of U.S. Department of Energy High Activity Cesium Sources Waste Stream at the Area 5 Radioactive Waste Management Site, Nevada National Security Site, Nye County, Nevada

This special analysis (SA) evaluates whether the Lawrence Livermore National Laboratory (LLNL) U.S. Department of Energy (DOE) High Activity Cesium (Cs) Sources waste stream (BCLADOEOSRPCS, Revision 0) is suitable for shallow land burial (SLB) at the Area 5 Radioactive Waste Management Site (RWMS) on the Nevada National Security Site (NNSS). Disposal of the LLNL DOE High Activity Cs Sources waste meets all U.S. Department of Energy (DOE) Manual DOE M 435.1-1, “Radioactive Waste Management Manual,” Chapter IV, Section P performance objectives (DOE 1999). The LLNL DOE High Activity Cs Sources waste stream is recommended for acceptance with the conditions that 1) the total waste stream cesium-137 ( 137 Cs) activity be limited to 1.7E16 becquerel (Bq) and 2) the waste be disposed greater than 4.4 meters (m) (14 feet [ft], 5 inches [in.]) below existing grade.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2011

MANAGING UNCERTAINTIES ASSOCIATED WITH RADIOACTIVE WASTE DISPOSAL: TASK GROUP 4 OF THE IAEA PRISM PROJECT

It is widely recognized that the results of safety assessment calculations provide an important contribution to the safety arguments for a disposal facility, but cannot in themselves adequately demonstrate the safety of the disposal system. The safety assessment and a broader range of arguments and activities need to be considered holistically to justify radioactive waste disposal at any particular site. Many programs are therefore moving towards the production of what has become known as a Safety Case, which includes all of the different activities that are conducted to demonstrate the safety of a disposal concept. Recognizing the growing interest in the concept of a Safety Case, the International Atomic Energy Agency (IAEA) is undertaking an intercomparison and harmonization project called PRISM (Practical Illustration and use of the Safety Case Concept in the Management of Near-surface Disposal). The PRISM project is organized into four Task Groups that address key aspects of the Safety Case concept: Task Group 1 - Understanding the Safety Case; Task Group 2 - Disposal facility design; Task Group 3 - Managing waste acceptance; and Task Group 4 - Managing uncertainty. This paper addresses the work of Task Group 4, which is investigating approaches for managing the uncertainties associated with near-surface disposal of radioactive waste and their consideration in the context of the Safety Case. Emphasis is placed on identifying a wide variety of approaches that can and have been used to manage different types of uncertainties, especially non-quantitative approaches that have not received as much attention in previous IAEA projects. This paper includes discussions of the current results of work on the task on managing uncertainty, including: the different circumstances being considered, the sources/types of uncertainties being addressed and some initial proposals for approaches that can be used to manage different types of uncertainties.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2013

Management of Low-Level Radioactive Waste from Research, Hospitals and Nuclear Medical Centers in Egypt - 13469

The application of radioisotopes and radiation sources in medical diagnosis and therapy is an important issue. Physicians can use radioisotopes to diagnose and treat diseases. Methods of treatment, conditioning and management of low level radioactive wastes from the use of radiation sources and radioisotopes in hospitals and nuclear medicine application, are described. Solid Radioactive waste with low-level activity after accumulation, minimization, segregation and measurement, are burned or compressed in a compactor according to the international standards. Conditioned drums are transported to the interim storage site at the Egyptian Atomic Energy Authority (EAEA) represented in Hot Labs and Waste Management Center (HLWMC) for storage and monitoring. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2013

Safety-Related Activities of the IAEA for Radioactive Waste, Decommissioning and Remediation - 13473

To fulfil its mandate and serve the needs of its Member States, the IAEA is engaged in a wide range of safety-related activities pertaining to radioactive waste management, decommissioning and remediation. One of the statutory obligations of the IAEA is to establish safety standards and to provide for the application of these standards. The present paper describes recent developments in regard to the IAEA's waste safety standards, and some of the ways the IAEA makes provision for their application. The safety standards and supporting safety demonstration projects seek to establish international consensus on methodologies and approaches for dealing with particular subject areas, for example, safety assessment for radioactive waste disposal. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2013

Radioactive Waste Management at the New Conversion Facility of 'TVEL'{sup R} Fuel Company - 13474

The project on the new conversion facility construction is being implemented by Joint Stock Company (JSC) 'Siberian Group of Chemical Enterprises' (SGChE) within TVEL{sup R} Fuel Company. The objective is to construct the up-to-date facility ensuring the industrial and environmental safety with the reduced impact on the community and environment in compliance with the Russian new regulatory framework on radioactive waste (RW) management. The history of the SGChE development, as well as the concepts and approaches to RW management implemented by now are shown. The SGChE future image is outlined, together with its objectives and concept on RW management in compliance with the new act 'On radioactive waste management' adopted in Russia in 2011. Possible areas of cooperation with international companies are discussed in the field of RW management with the purpose of deploying the best Russian and world practices on RW management at the new conversion facility. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2013

Verification of the Accountability Method as a Means to Classify Radioactive Wastes Processed Using THOR Fluidized Bed Steam Reforming at the Studsvik Processing Facility in Erwin, Tennessee, USA - 13087

Studsviks' Processing Facility Erwin (SPFE) has been treating Low-Level Radioactive Waste using its patented THOR process for over 13 years. Studsvik has been mixing and processing wastes of the same waste classification but different chemical and isotopic characteristics for the full extent of this period as a general matter of operations. Studsvik utilizes the accountability method to track the movement of radionuclides from acceptance of waste, through processing, and finally in the classification of waste for disposal. Recently the NRC has proposed to revise the 1995 Branch Technical Position on Concentration Averaging and Encapsulation (1995 BTP on CA) with additional clarification (draft BTP on CA). The draft BTP on CA has paved the way for large scale blending of higher activity and lower activity waste to produce a single waste for the purpose of classification. With the onset of blending in the waste treatment industry, there is concern from the public and state regulators as to the robustness of the accountability method and the ability of processors to prevent the inclusion of hot spots in waste. To address these concerns and verify the accountability method as applied by the SPFE, as well as the SPFE's ability to control waste package classification, testing of actual waste packages was performed. Testing consisted of a comprehensive dose rate survey of a container of processed waste. Separately, the waste package was modeled chemically and radiologically. Comparing the observed and theoretical data demonstrated that actual dose rates were lower than, but consistent with, modeled dose rates. Moreover, the distribution of radioactivity confirms that the SPFE can produce a radiologically homogeneous waste form. The results of the study demonstrate: 1) the accountability method as applied by the SPFE is valid and produces expected results; 2) the SPFE can produce a radiologically homogeneous waste; and 3) the SPFE can effectively control the waste package classification. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗