Excess Plutonium Safe Storage
The Computational and Experimental Investigations of Problems of Excess Plutonium Safe Storage
Tech Area / Field
- ENV-MRA/Modelling and Risk Assessment/Environment
- ENV-RWT/Radioactive Waste Treatment/Environment
- ENV-WPC/Water Pollution and Control/Environment
3 Approved without Funding
Keldysh Institute of Applied Mathematics, Russia, Moscow
- MIFI, Russia, Moscow\nVNIITF, Russia, Chelyabinsk reg., Snezhinsk
- Texas A&M University, USA, TX, College Station
Project summaryTo remove excess of plutonium from military employment, it is necessary to resolve today many complicated problems. Large groups of scientists are working now all over the world with these urgent challenges. Independently of resolving problem of a future utilization of plutonium (processing, using as a fuel, long-term storage etc.), there do exist a number of problems which in any case are of cardinal importance.
The proposed Project is directed to solution of some of the most actual problems mentioned above.
Necessity of long-term storage of excess plutonium requires solving the problem of safety during all stages of storage. In this connection, the great attention must be paid to risk analysis, - an estimation and management of risk of storage and transportation of plutonium. Increasing of terrorist action threat makes problem of plutonium safe storage more essential. The analysis, estimation and management of risk are connected with use of the uncertain information, therefore methods of the analysis and control of incidents on the basis of fuzzy-probabilistic models will be developed.
Necessity of long-term storage of excess plutonium requires solving the problem of constructing reliable and safe methods for its storage. Solution of this problem is connected, first of all, with constructing reliable containers for storage of plutonium. Off-normal loads on the container may result from accidental processes taking place both inside and outside. For studying of these processes in the framework of the Project it is expected to develop physical and mathematical models as well as the corresponding numerical methods and computer codes for modeling the basic neutron-physical and thermal-hydrodynamic phenomena inside the container. This problem will be considered including the equations of elasticity for the container vessel also.
For investigation of container behavior at off-normal external loads there will be developed and validated approximate computational methods and codes based on comprehensive employment of available experimental data. The primary goal of this direction of investigations is to determine load values which at accidental impacts may lead to unsealing of AT400R-container employed for transportation and storage of Fissile Materials (FM).
The Project is supposed to simulate destruction of the containers and storage facility caused by uncontrollable energy release. Dynamics of the destruction of one container inside the storage facility will be analyzed in detail for a specified range of released energy, depending on the different accident scenarios. The analysis is supposed to include the effect of the structural elements of the destroyed container on the neighboring containers. Interaction of these elements with the storage facility structures will be examined as well as the process of destruction of the storage facility itself. For this purpose, the existing 2D codes SINARA and MECH will be modified. New equations of state and characteristics of the container and storage facility materials will be developed and the existing ones will be updated and improved with due account of dynamic loads. A physically-based mathematical model will be developed to simulate the processes of brittle media motion within the specified energy release range. The modified codes will be verified against the experimental data. Due to significant time difference between the destruction of the container and spray of the fragments, simulations will use both codes with data exchange between the codes for a more detailed description of the different phases of the destruction processes. The obtained data on the state of the storage facility structures can be used as initial data for analyzing dispersion of radioactive materials beyond the storage facility.
Special attention is required by operations on ecological situation estimation in case of emergency situations during transportation and storing plutonium, which lead to the damage of stuff containers. Also in the Project the failures are considered that involve the most serious consequences, being accompanied by disintegration of plutonium containing materials and transfer of aerosol over distances about several tens of kilometers. We suggest, using the KIAM programs for describing three-dimensional multiphase filtration, computing fluid flows that contain radioactive impurities and take place in fractured porous media in the presence of macroscopic fractures. The features of proposed research are, first, opportunity of multiphase problems investigation, i.e. taking into account, in particular, gaseous component in the radioactive impurities. Second, the programs allow calculating the fluid and radioactive impurities distribution both in block structures and in fractures. This allows solving the multi-scale in time problems because current in fractures is formed in essentially less time than characteristic times it happens in blocks. Knowing the fluid distribution in medium it's possible then to solve questions of radioactive contamination of the soil and the atmosphere. The main purpose of this section is to obtain estimates concerning the environment pollution with plutonium plus the possible inhalation doses. Within the framework of the Project it is planned the development of methods and programs for calculating atmospheric transport of plutonium aerosols produced in an accident.
The extremely high toxicity of plutonium has caused to enter extremely high normative requirements for its contents in the environment and, mainly, in the air. It requires creation highly precise instruments and methods for monitoring objects of the environment on transportation ways and around plutonium storage sites.
Within the framework of the Project it is supposed to develop a technique of definition of plutonium contents in the environmental samples of different width. It is supposed to study a capability of measurement of the plutonium contents by method of registration fission fragment leaking the samples, and also by crystal diffraction method applied to characteristic radiation of a plutonium.
The work also supposes developing, for plutonium created as a result of an accidental release, mathematical models of migration in sweet-water systems, generating the prognosis of a self-cleaning of aqueous systems and working out the guidelines on acceleration of processes of cleaning up.
All three participating in the Project organizations played a leading role in designing nuclear weapons in the former Soviet Union. KIAM RAS has always performed these investigations in close contacts with two leading nuclear centers of the State - RFNC-VNIITF and RFNC-VNIIEF. MEPhI always provided the main quantity of highly skilled specialists for the above mentioned nuclear centers.
In the present work it is expected to employ the experience accumulated during developing weapons. First of all, it is related to physical and mathematical models, numerical methods and extensive experimental data on different processes related to the problem of plutonium treatment. In the framework of this Project it is proposed to join forces of 40 highly skilled scientists and engineers:
- 13 persons from KIAM,
- 15 persons from RFNC-VNIITF,
- 12 persons from MEPhI.
The most part of these persons have the direct relation to designing weapons of mass destruction and vehicles for their transportation. The Project allows to reorient these high level scientists to the solution of civil problems and, first of all, to the provision of the safe transition from a highly militarized society to a peaceful civil community.
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