Molybdenium Extraction from Reactor Fuel
Experimental Substantiation of Technology for Molybdanium-99 Extraction from Fuel Solution of Fluid-fuel Reactor and Design Development of the Medical Isotope Production Complex
Tech Area / Field
- FIR-ISO/Isotopes/Fission Reactors
3 Approved without Funding
FEI (IPPE), Russia, Kaluga reg., Obninsk
- State Special Project Institute, Russia, Moscow\nState Enterprise Krasnaya Zvezda, Russia, Moscow
Project summaryThe project is aimed at developing and experimental validation of the process of Mo-99 extraction from the fuel of a liquid fuel reactor and studying the design of a complex for Mo-99 production on the basis of liquid fuel reactors.
Nuclear medicine has become nowadays an important part of the health care systems in the industrially developed countries. One of key factors of its development is the reliable and permanent delivery of radioactive nuclides in use.
Being the most spread medical radioactive nuclide Mo-99 is basically manufactured now by solid HEU targets irradiation in thermal neutron reactors followed by deep purification of the extracted Mo-99. Mo-99 produces a daughter nuclide Tc-99m that is widely used in diagnostics of cancer, cardio-vascular and some other diseases. In the world the share of Tc-99m employment in diagnostic treatment of nuclear medicine is more than 80 per cent.
This process suffers from a number of disadvantages:
- Uranium is used ineffectively. It results in the need for regeneration of uranium, which has not been burned up, and utilization of a sizeable amount of radioactive waste. This technology gives 13 Ci of radioactive waste per up to 1 Ci of product Mo-99.
- Major part of the reactors for Mo-99 production have long been put in operation (several tens of years ago) and must be decommissioned in the nearest future (in 5 to 10 years).
It is our experts' opinion that a new and effective process of radioactive isotope production is the one based upon usage of a liquid fuel reactor and process equipment coupled with it for Mo-99 extraction from the liquid fuel solution. The proposed process enables to obviate the need for using outdated large power research reactors and to provide Mo-99 to be manufactured by 50 to 200 kW small reactors. Simultaneously, the amount of radioactive waste could be nearly 100 times less.
Liquid fuel reactors are characterized by a high degree of nuclear and radiological safety as it has been shown by the world operational experience of more than 20 reactors in Russia and the USA. Although the proposed technology is based on proven liquid fuel reactor technology, there are several aspects beyond the accumulated experience.
First, a liquid fuel reactor equipped with an outer loop for steady extraction of Mo-99 from the liquid fuel solution and its recycling to the core has never been in operation before.
Second, there is no experience of operation of a liquid fuel reactor under natural circulation at the power level of 100-200 kW (all existing reactors have been operated at 50 kW). In this case one has to study the conditions of reactor core cooling in the regime of natural circulation of the liquid fuel solution. Another important problem to be investigated is that of higher formation of radiolythic gases and their recombination.
In solving the problem of liquid fuel reactor usage for Mo-99 radioactive isotopes, the Project is to demonstrate the feasibility of the proposed process.
It should be mentioned that development of the process of Mo-99 production is to become an alternative field of professional effort for weapons scientists and engineers to be involved in the Project for nearly two years at least.
The Expected Results
The Project implementation will result in:
- development a process of Mo-99 extraction from the circulating fuel solution and its experimental validation, resolution of problems of releasing of a reactor loop for industrial production of Mo-99,
- a conceptual design of a 200 kW liquid fuel reactor,
- solving problems of reactor core cooling in the regime of natural circulation and radiolythic gases recombination,
- implementation of R&D of the whole production complex equipment, its characteristics and arrangement. It would enable to estimate the finance required for commercial realization of this technology.
The results of implementation of the Project will help define the principal fields of cooperation with interested firms to construct a complex for Mo-99 production in the territory of Russia on the basis of the proposed technology.