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Monograph "Radiowaste Transmutation"

#3064


Monograph "Physics of Nuclear Reactor Long-lived Radiowastes Incineration (Neutron Induced Transmutation)"

Tech Area / Field

  • ENV-RWT/Radioactive Waste Treatment/Environment
  • FIR-FUC/Fuel Cycle/Fission Reactors
  • FIR-FUE/Reactor Fuels and Fuel Engineering/Fission Reactors

Status
3 Approved without Funding

Registration date
10.06.2004

Leading Institute
MIFI, Russia, Moscow

Collaborators

  • Lawrence Livermore National Laboratory, USA, CA, Livermore\nGeorgia Institute of Technology, USA, GA, Atlanta\nPacific Northwest National Laboratory, USA, WA, Richland\nBrookhaven National Laboratory, USA, NY, Upton

Project summary

Nuclear waste management is one of the key issues governing the future status of nuclear power technology. Technologically available approaches to nuclear waste management are mostly based on passive barriers that prevent the release of radiologically hazardous nuclides into the biosphere.

Along with that an alternative approach to the transmutation of radioactive nuclides into less hazardous or even stable isotopes have also being investigated. Last decade of the previous century the main focus of attention in transmutation studies was directed to seeking ways for efficient transmutation of Minor Actinides (MA) in fission reactors, operated in critical mode (conventional fission reactors) and in ADS-system (subcritical mode).

Essentially different approach was proposed and developed at MEPhI (Moscow Engineering Physics Institute - The State University). The milestone of this approach is that it envisages application of three technologies:


· Technology of nuclear power reactors;
· ADS transmutation technology;
· Fusion technology.

It is stressed that important role in attaining effective and fast transmutation should play Fusion Technology. Fusion potentialities might appear as a crucial element in the transmutation strategy as a whole. Since the main emphasis here is not on power but on neutron production, it seems advisable to study (dt) plasma with a reduced fraction of tritium. Necessary tritium breeding could be performed in the blanket periphery with neutrons inevitably escaping the high flux zone destined to transmutation of nuclear wastes. It should be stressed that in view of different nuclear properties of nuclides in waste, to transmute them within only one technology is obviously a complex task. So, ADS technology will be effective in transmutation of several nuclides of Fission Products and for burning Curium fraction of Minor Actinides. In order to play such a role high current accelerators and blanket modules need to be developed without fissionable nuclides ( or blanket modules with suppressed fission) to reduce associated power release. On the basis of the above, it is demonstrated that most hazardous nuclear wastes could be effectively eliminated both with near-term ADS technology and fusion technologies.

The authors of the present project have accumulated a considerable volume of published materials on transmutation, the systematization and summary of which is worthy of inclusion in the monograph. Intermediate, significant results obtained by authors of this approach have been reported at several prestigious international forums:

1. Workshop on Nuclear Transmutation of Long-Life Nuclear Power Radiowastes, Obninsk, Russia, 1991;


2. Specialists Meeting "Use of Fast Reactors for Actinide Transmutation", IAEA, Obninsk, Russia, 1992;
3. The Second International Seminar on Proton Accelerator-Based Transmutation of Long-Life Radioactive Wastes and Utilization of Weapons-Grade Plutonium, Moscow, Russia, 1994;
4. The International Conference on Accelerator-driven Transmutation Technologies and Applications, Las Vegas, USA, 1994;
5. GLOBAL’95, Versailles, France, 1995;
6. ICENES-1996, Obninsk, Russia, 1996;
7. The Second International Symposium "Global Environment and Nuclear Energy Systems - GENES-2", Tsuruga, Japan, 1996;
8. The Second International Conference on Accelerator-Driven Technology and Application, Kalmar, Sweden, 1996;
9. GLOBAL’97, Yokohama, Japan, 1997;
10. The Third International Symposium "Global Environment and Nuclear Energy Systems - GENES-3", Tokyo, Japan, 1999;
11. GLOBAL’99, Snow King Resort, Wyoming, USA, 1999;
12. The International Seminar on Advanced Nuclear Energy Systems Toward Zero Release of Radioactive Wastes, Susono, Japan, 2000.

The aim of the project:

· To summarize transmutation studies performed worldwide over the last 10-15 years;


· To formulate a set of criteria to estimate the efficiency of transmutation and, with these criteria, to analyze the potential of fission reactors, Accelerator-Driven Systems (ADS) and Fusion Neutron Source (FNS) in transmuting long-life nuclides from spent fuel of current nuclear power reactors;
· To analyze peculiarities and the condition of waste transmutation in its elemental form i.e without isotope separation prior to transmutation and in isotope separation option;
· To make a conceptual design of ADS and FNS blankets oriented exclusively to waste transmutation;
· To compete a draft monograph for publication.

It will be observed the main approaches in transmutation studies of last decade in the Europe and in the USA. Particularly influential transmutation studies include those performed in Europe (initiated and encouraged by Prof.Salvatores (Cadarash, France) and Noble Prize Winner Carlo Rubia (CERN, Switzerland), in the USA (Dr. C. Bowman, LANL research team), Japan (JAERI, research teams of several universities), аnd in Russia (Institute of Theoretical and Experimental Physics, Research and Development Institute of Power Engineering). It is worthy of note that the number of journal articles on waste transmutation has notably shrunk of late. The current situation in transmutation research was summarized at the International Seminar on Advanced Nuclear Energy Systems Toward Zero Release of Radioactive Wastes, Susono, Shizuoka, Japan, Nov 6-9, 2000. Some authorities and famous scientists, including Prof. Salvatores and G.Kessler (Carlsruhe, Germany) shared the opinion that it appeared difficult to achieve high transmutation efficiency for most wastes in fission reactors and near-subcritical ADS; only several nuclides could be transmuted in them: Np, Am, 129I and 99Tc.

Last several years the development of MEPhI approach has been conducted in close cooperation with the Tokyo Institute of Technology-TIT (Tokyo, Japan).

The following tasks have now been completed:

· elaboration of a general approach to transmutation of nuclear waste,


· formulation of a set of criteria to assess transmutation efficiency;
· conceptual design of waste transmuters based on computer simulation of neutronics in their vital components.

It is concluded that progress is required in developing the accelerator technique and plasma confinement characteristics to challenge the requirements of waste transmutation from the view point of excess neutron generation. Application of high flux blanket segments could improve the efficiency of waste transmutation in terms of transmutation rate. All this will result in a nuclear energy system structure, in which the fraction of power generation attributed to transmuters will be minimized. Needless to say that reprocessing technology should be included in the structure of this advanced nuclear energy system.

In the framework of the proposed project some additional studies are required on the transmutation potentialities of accelerator and fusion technologies. This is primarily concerned with the potentialities of waste transmutation without isotope separation of several fission products such as Selenium and Tin, and elaboration on conceptual ADS for transmutation of Curium fraction of Minor Actinides.

In the final monograph the main focus of attention will be directed to the characterization of transmutation environment achievable with the application of various nuclear technologies. The monograph will have the chapters:

Chapter I. Radiowastes: composition and hazard indexes


1.1. Fuel cycle and radiowastes at various stages from uranium ore excavation to fuel discharge from nuclear reactor;
1.2. Composition of spent fuel discharged from uranium-fuelled reactors
1.3. Particular features of spent fuel in (U-Pu)-,233U-Th)-and mixed fuel cycles
1.4. Characteristics of radiological hazards
Chapter II. Principle of radiological equivalency between excavated uranium and disposed waste
2.1. Basic principles of radioactivity migration
2.2. Differential and integral approaches. Migration coefficients
2.3. Long-term waste management strategy in a view of principle of radiological equivalency
2.4. Obstacles to completing the principle of radiological equivalency
2.5. EPA-standard to waste disposal
Chapter III. Peculiarities of neutron induced transmutation of long-life fission products
3.1. Irradiation of long-life fission products in neutron field
3.2. Transmutation of long-life products in a full-scale nuclear energy system
3.3. Time to approach equilibrium for nuclides in fast and thermal neutron fields
3.4. Transmutation cycle. Loss to waste through recycling
3.5. Neutron requirements for fission product transmutation
3.6. Peculiarities of isotope transmutation
3.7. General criteria for estimation of transmutation efficiency
Chapter IV. Excess neutron generation and concept of high flux transmutation blankets (critical and subcritical systems)
Chapter V. Neutronics of long-life fission product transmutation (99Tc, 129I, 135Cs, 107Pd, 126Sn, 79Se, 93Zr, 90Sr, 137Cs).
Chapter VI. Transmutation of Minor Actinides
6.1. Accumulation of Minor Actinides in UOX and MOX fueled reactors
6.2. Neutronics properties of MA, important from the view-point of their incineration
6.3. Potential of MA in improving the proliferation resistance of Plutonium
Chapter VII. Nuclear energy systems backed up by transmutation cycle
7.1. Conceptual approaches to Nuclear energy system with waste transmutation
7.2. Energy associated with waste transmutation
7.3. International nuclear islands to protect fuel and transmute wastes

The project will be completed with the text of the monograph prepared for publication.

Role of Foreign Collaborators. In the course of the proposed project information exchange with the Foreign Collaborators will be arranged for: joint development of a detailed plan for the monograph and joint discussion and interpretation of the results obtained in numerical studies and introduction of the most interesting results into the monograph.

The main idea of the proposed monograph might be formulated like follows: Based upon experience accumulated in transmutation R&D over the last decade in Russia, Japan, the USA and Europe, the transmutation potential of nuclear power technology is high, and it is prudent to start development of a nuclear fuel cycle backed by neutron induced transmutation of most hazardous nuclear waste without isotope separation prior to irradiation in transmuters.


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