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Immobilization of High-Level Wastes

#3760


Immobilization of High-Level Wastes in Resistant Mineral-Like Materials in the Self-Propagating High Temperature Synthesis (SHS) Mode

Tech Area / Field

  • ENV-RWT/Radioactive Waste Treatment/Environment

Status
3 Approved without Funding

Registration date
02.05.2007

Leading Institute
FEI (IPPE), Russia, Kaluga reg., Obninsk

Collaborators

  • Universita degli Studi di Milano / Dipartamento di Fisica, Italy, Milan\nNexia Solutions Ltd, UK, Preston\nUniversity of Thessaloniki / Department of Chemistry, Greece, Thessaloniki\nAREVA / AREVA TA, France, Gif-sur-Yvette Cedex\nOak Ridge National Laboratory, USA, TN, Oak Ridge\nEmergencies Science and Technology Division Environment Canada, Canada, ON, Ottawa\nRoosevelt University, USA, IL, Chicago\nState University of New York at Stony Brook / Department of Chemistry, USA, NY, Stony Brook\nForschungszentrum Jülich GmbH, Germany, Jülich\nUniversity of Naples Federico II / Dipartamento di Ingegneria dei Materiali e Della Produzione, Italy, Naples\nTexas A&M University / College of Engineering, USA, TX, College Station\nUniversity of Florida / Department of Geological Sciences, USA, FL, Gainesville\nNuclear Safety Solutions Limited, Canada, ON, Toronto\nRamboll Storvik, Norway, Skoyen\nUniversity of Sheffield / Department of Engineering Materials / Immobilisation Science Laboratory, UK, Shiffield

Project summary

The urgency is dictated by unprocessed high-level waste generated in significant amounts at atomic power plants, nuclear centers and marine nuclear power plants. The waste must be conditioned (decontaminated) by immobilization of radionuclides within materials capable of their long-term positive confinement.

The proposed out-of-furnace high temperature energy-saving process based on self-propagating high temperature synthesis (SHS) will make it possible to speed up decontamination of HLLW accumulated.

The objective – development of energy-saving and environmentally sound technology of high level liquid waste conditioning by means of sorption extraction of radionuclides and their immobilization in stable mineral-like matrix materials under the self-propagating high temperature synthesis (SHS) mode.

State of the art in the field.

Russia and foreign states are making major R&D efforts related to conditioning HLW, including incorporation of radionuclides into mineral-like matrices of high resistance to radiation and natural media. Though much attention is being given to the R&D (conferences, reports, financing (grants), etc.), economical and ecological parameters of the technologies developed are far from perfect. The central problems are complicated techniques of HLLW high temperature conditioning and high power consumption.

Сonventional technique. Only vitrification as a high-level waste conditioning method has been presently placed in commercial operation (France, USA, Great Britain, Belgium, Japan, Russia). The main troubles of the technique are a sophisticated power-intensive equipment as well as thermal and radiation instability of a target product, with a resultant devitrification and cracking of the matrix and hence a lower fixation of radionuclides.

The essence of the technology as proposed

The technology of SMM production in the SHS mode as proposed in the Project is characterized by more efficient technical and economic as well as environmental performances. The out-of-furnace technology is based on the use of solid-phase spontaneous exothermal processes, which require no external power.

A key feature of the method of liquid HLW conditioning as proposed in the Project consists in a complex solution of the problem, which involves successive solution of two main related tasks:

  • Sorption-crystallization extraction of radionuclides from liquid HLW by special sorbents containing the elements, which are stabilizing components of future SMM at the same time;
  • Formation of radionuclide doped SMM suitable for disposal under the SHS mode.

Thus, after having solved the first task the sorbent containing radionuclides is introduced into the SHS-charge and then it participates in high-temperature synthesis of end product (SMM), which immobilizes radionuclides.

The proposed SHS immobilization technology is relatively simple and waste-free. It needs a few operation stages and no external heating source. These advantages enable for a high standard of mechanization and automation to be realized.

Competence of the Project participants.

The experts take part in the Project implementation, which have at least 10-20 years of experience in:

  • radioactive waste (RW) management;
  • development of technologies of RW and HLW isolation from the environment;
  • synthesis, investigation of geochemical properties and structure of analog materials of natural minerals;
  • thermodynamic, kinetic and radiochemical investigations of solid phase processes;
  • development of sorption methods of purifying liquid mediums.

Expected Results and Their Application. As a result of the work under this Project, the following will be executed:
  • development of a new method and technology of HLW radionuclide isolation from the biosphere;
  • determination of main process parameters of waste conditioning;
  • production of demonstration SMM specimens based on real solutions containing HLW radionuclides.

The proposed energy-saving and environmental technology of HLW conditioning can be used in domestic and foreign nuclear centers of SNF processing in designing appropriate industrial equipment of new alternative methods of HLW disposal using matrix materials of the second generation Matrix materials of first generation are glasses used industrially now..

Meeting ISTC Goals and Objectives

This project is in a complete agreement with the fulfillment of ISTC principal targets and tasks:

  • it offers the possibility for scientists and experts of Russian Federation whose activity was related to weapons and especially those who have knowledge and experience in the field of mass distraction weapons and missile delivery systems to use their abilities for the peaceful activity;
  • it supports fundamental and applied investigations and technology development in peaceful purposes especially in the field of environment protection, energy generation and safety assurance in nuclear power;
  • it helps to solve national and international technical problems (besides those indicated above);
  • it supports the conversion to market economy, which meets social needs.

Scope of work. The development of a new method of radionuclide immobilization and HLW conditioning technology, which results in producing demonstration actual-size specimens containing HLW radionuclides, requires the implementation of the following scope of work:
  • Chemical- technological parameters and equipment for recovery of radionuclides from fractionated HLLW to produce sorption-crystallized concentrates (SCC) by hyperstoichiometric sorption on porous oxides.
  • Special high temperature thermophysical experimentation and calculation.
  • Mineralogical, physical, chemical and structural properties of stable natural and synthetic oxide inorganic minerals to prove the choice of optimum matrix materials for SHS immobilization.
  • Chemical- technological parameters and equipment for SHS immobilization of HLLW within a stable matrix.
  • A technology for compacting SHS- products suitable for environmentally safe disposal.
  • The phase composition and structure of a target SHS-product examined by X-ray diffraction, X-ray fluorescence and electron scanning microscopy.
  • HLW fixation soundness within a matrix on the strength of radionuclides leaching tests of SHS-products.
  • Technical documentation for a radiochemical work bay fitted with a demonstration equipment for SHS conditioning of HLLW.

Role of Foreign Collaborators/Partners
  • participation in the development of project proposal and work plan;
  • information exchange in the course of the project implementation;
  • mutual review of technical reports;
  • joint seminars, workshops, meetings, consultations;
  • verification of results using independent methods and /or equipment;
  • joint or parallel investigations.


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