Self-disposal option for highly-radioactive waste reconsidered

2012 ◽  
Vol 1475 ◽  
Author(s):  
M. Ojovan ◽  
V. Kascheev ◽  
P. Poluektov

ABSTRACTSelf-disposal option for heat-generating radioactive waste (HLW, spent fuel, sealed radioactive sources) known also as rock melting concept was considered in the 70s as a viable but alternative disposal option by both DOE in the USA and Atomic Industry Ministry in the USSR. Self-disposal is currently reconsidered with a novel purpose – to penetrate into the very deep Earth’s layers beneath the Moho’s discontinuity and to explore Earth interior. Self-descending heat generating capsules can be used for disposal of dangerous radioactive wastes in extremely deep layers of the Earth preventing any release of radionuclides into the biosphere. Descending of capsules continues until enough heat is generated by radionuclides to provide partial melting of surrounding rock. Estimates show that extreme depths of several tens and up to hundred km can be reached by capsules which could never be achieved by other techniques.

Author(s):  
Michael I. Ojovan ◽  
Pavel P. Poluektov ◽  
Vladimir A. Kascheev

Self-descending heat generating capsules can be used for disposal of dangerous radioactive wastes in extremely deep layers of the Earth preventing any release of radionuclides into the biosphere. Self-disposal option for heat-generating radioactive waste such as spent fuel, high level reprocessing waste or spent sealed radioactive sources, known also as rock melting concept, was considered in the 70s as a viable alternative disposal option by both Department of Energy in the USA and Atomic Industry Ministry in the USSR. Self-disposal is currently reconsidered as a potential alternative route to existing options for solving the nuclear waste problem and is associated with the renaissance of nuclear industry. Self-disposal option utilises the heat generated by decaying radionuclides of radioactive waste inside a heavy and durable capsule to melt the rock on its way down. As the heat from radionuclides within the capsule partly melts the enclosing rock, the relatively low viscosity and density of the silicate melt allow the capsule to be displaced upwards past the heavier capsule as it sinks. Eventually the melt cools and solidifies (e.g. vitrifies or crystallizes), sealing the route along which the capsule passed. Descending or self-disposal continues until enough heat is generated by radionuclides to provide partial melting of surrounding rock. Estimates show that extreme depths of several tens and up to hundred km can be reached by capsules which could never be achieved by other techniques. Self-disposal does not require complex and expensive disposal facilities and provides a minimal footprint used only at operational stage. It has also an extremely high non-proliferation character and degree of safety. Utilisation of heat generated by relatively short-lived radionuclides diminishes the environmental uncertainties of self-disposal and increases the safety of this concept. Self-sinking heat-generating capsules could be launched from the bottom of the sea as well as from intermediate-depth or deep boreholes. Self-disposal can also be used with a novel purpose — to penetrate into the very deep Earth’s layers beneath the Moho’s discontinuity and to explore Earth interior.


Author(s):  
A. Abramenkovs ◽  
J. Malnacs

In May 1995, the Latvian government decided to shut down the Salaspils Research Reactor (SRR). The reactor is out of operation since July 1998. A conceptual study for the decommissioning of SRR has been carried out by Noell-KRC-Energie- und Umwelttechnik GmbH at 1998–1999. The Latvian government decided to start the direct dismantling to “green field” in October 26, 1999. The upgrade of decommissioning and dismantling plan was performed in 2003–2004 years, which change the main goal of decommissioning to the “brown field”. The paper deals with the SRR decommissioning experience during 1999–2010. The main decommissioning stages are discussed including spent fuel and radioactive wastes management. The legal aspects and procedures for decommissioning of SRR are described in the paper. It was found, that the involvement of stakeholders at the early stages significantly promotes the decommissioning of nuclear facility. Radioactive waste management’s main efforts were devoted to collecting and conditioning of “historical” radioactive wastes from different storages outside and inside of reactor hall. All radioactive materials (more than 96 tons) were conditioned in concrete containers for disposal in the radioactive wastes repository “Radons” at Baldone site. The dismantling of contaminated and activated components of SRR systems is discussed in paper. The cementation of dismantled radioactive wastes in concrete containers is discussed. Infrastructure of SRR, including personal protective and radiation measurement equipment, for decommissioning purposes was upgraded significantly. Additional attention was devoted to the free release measurement’s technique. The certified laboratory was installed for supporting of all decommissioning activities. All non-radioactive equipments and materials outside of reactor buildings were released for clearance and dismantled for reusing or conventional disposing. Weakly contaminated materials from reactor hall were collected, decontaminated and removed for clearance measurements.


Author(s):  
Anthony Shadrack ◽  
Chang-Lak Kim

The development of a lasting solution to radioactive waste management is a critical issue for future nuclear applications. When assessing radioactive waste disposal options factors such as volume of waste and sustainability of the plan must be considered. This paper describes basic plans for the disposal of Low- and intermediate-level radioactive wastes (LILW) expected to be generated from nuclear power plants for countries starting nuclear power program for the first time. The purpose of this paper was to develop a disposal option for Low- and intermediate level radioactive wastes for new comer countries planning to build at least two nuclear power units. A LILW disposal plan was developed by considering countries’ radioactive waste generation data from pressurized water nuclear reactors. An on-site storage facility of 1,000 m3 for LILW at NPPs sites for a period 10 years pending final disposal was recommended. It was concluded that storage and disposal processes are complementary with each other, therefore; both programs should be complemented for effective management and control of radioactive wastes. This study is important as an initial implementation of a national Low- and intermediate level wastes (LILW) disposal program for countries planning to build nuclear power plants for the first time.


1998 ◽  
Vol 47 (2) ◽  
pp. 409-425 ◽  
Author(s):  
Amelia de Kageneck ◽  
Cyril Pinel

The importance of the safe and environmentally sound management of radioactive wastes had been strongly reaffirmed by the United Nations Conference on Environment and Development, held in Rio de Janeiro in 1992. This question was dealt with in Chapter 22 on “safe and environmentally sound management of radioactive wastes” of Agenda 21, adopted at the time of the Conference, which specifically referred to the necessity for States to “support efforts within IAEA to develop and promulgate radioactive wastes safety standards or guidelines and codes of practice as an internationally accepted basis for the safe and environmentally sound management and disposal of radioactive waste”. This political statement was probably the first step in the process which has led to the adoption, in September 1997, of the Joint Convention on the Safety of Spent Fuel Management and on the Safety of Radioactive Waste Management (hereafter the “Joint Convention”). In 1994 the importance of elaborating safety standards for radioactive waste management appears again in the Convention on Nuclear Safety of 20 September 1994, the Preamble to which (paragraph ix) reads: “Affirming the need to begin promptly the development of an international convention on the safety of radioactive waste management as soon as the ongoing process to develop waste management safety fundamentals has resulted in broad international agreement.”


Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2630
Author(s):  
Luigi Cosentino ◽  
Quentin Ducasse ◽  
Martina Giuffrida ◽  
Sergio Lo Meo ◽  
Fabio Longhitano ◽  
...  

In the framework of the MICADO (Measurement and Instrumentation for Cleaning And Decommissioning Operations) European Union (EU) project, aimed at the full digitization of low- and intermediate-level radioactive waste management, a set of 32 solid state thermal neutron detectors named SiLiF has been built and characterized. MICADO encompasses a complete active and passive characterization of the radwaste drums with neutrons and gamma rays, followed by a longer-term monitoring phase. The SiLiF detectors are suitable for the monitoring of nuclear materials and can be used around radioactive waste drums possibly containing small quantities of actinides, as well as around spent fuel casks in interim storage or during transportation. Suitable polyethylene moderators can be exploited to better shape the detector response to the expected neutron spectrum, according to Monte Carlo simulations that were performed. These detectors were extensively tested with an AmBe neutron source, and the results show a quite uniform and reproducible behavior.


1981 ◽  
Vol 6 ◽  
Author(s):  
I-Ming Chou

Rock-salt deposits have been considered as a possible medium for the permanent storage of high-level radioactive wastes and spent fuel. Brine inclusions present in natural salt can migrate toward the waste if the temperature and the temperature gradients in the vicinity of the radioactive waste are large enough. This migration is due to the dissolution of salt at the hot side of the salt-brine interface, ion diffusion through the brine droplet, and the precipitation of salt at the cold side of the salt brine interface.


1981 ◽  
Vol 11 ◽  
Author(s):  
H. C. Burkholder

In response to draft radioactive waste disposal standards, R&D programs have been initiated in the United States which are aimed at developing and ultimately using radionuclide transport-delaying (e.g., long-lived waste containers) and radionuclide transport-controlling (e.g., very low release rate waste forms) engineered components as part of the isolation system. Before these programs proceed significantly, it seems prudent to evaluate the technical justification for development and use of sophisticated engineered components in radioactive waste isolation.


2019 ◽  
pp. 23-29
Author(s):  
M. Semerak ◽  
S. Lys ◽  
T. Kovalenko

The possibility of the plasma processing of low-level or intermediatelevel radioactive wastes in the reactor equipped with arc plasmatrons is shown. The reactor design for the plasma processing of the radioactive wastes that allows promoting the efficiency of the plasma processing of the radioactive wastes (RAW) by the increasing of the speed and the intensity of the plasma pyrolysis is proposed. The various methods for RAW preparation, dosage and supply into the plasmochemical reactor have been investigated. The waste which is supplied to the reactor can be in various aggregate states (solid, liquid or gaseous) depending on which different kinds of preparation, dosage, and supply of RAW materials to the plasmochemical reactor are used. The solid waste must be ground for increasing of the phase separation surface. The degree of grinding of the wastes depends on their further reprocessing. The reactor allows processing of the mixed-type radioactive waste, which includes both combustible and non-combustible components. The wastes can be packed or ground up. The selected technological regimes should provide temperature from 1500 °C in the melting chamber to 250 °C in the upper part in the pyrogas exit zone to prevent the flow-out of volatile compounds of a series of radionuclides and heavy metals from the furnace and to process the waste and merge slag melt without adding of fluxes. The fused slag is a basaltiform monolith, where the content of aluminum oxide reaches 28%; silicon oxide up to 56%; sodium oxide from 2.5 to 11 %. The resulting radioactive slag is extremely resistant to the chemical influence. The pyrogas produced in the shaft furnace will have a heating value of about 5 MJ/nm3. This allows, after initial heating by plasmatron, maintaining the required temperature in the combustion chamber due to the heat released during combustion of the pyrogas, when the plasma heating source is switched off, and burning the resin and soot effectively. It is proved that the plasma technology for RAW reprocessing allows a significant reduction in waste volumes and waste placement for long-term storage with the most efficient use of storage facilities.


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