Questions concerning safety, nonproliferation, monitoring of nuclear materials, civilian responsibility for nuclear risks, physical protection, transport operations, and others are analyzed within the framework of the INPRO project in application to transportable nuclear energy facilities. Essentially, the operative nuclear law and the experience of world nuclear power make it possible to solve the problems of the legal basis for the life cycle of transportable nuclear power facilities. To attain a system with the optimal accessibility, effectiveness, and safety, the nuclear power facilities will have to be adapted to the new specific requirements and conditions, and the international legal basis will have to be made more precise. International Project INPRO.In his speech at the Millennium Summit at the United Nations on September 6, 2000, V. V. Putin, President of the Russian Federation, advanced an initiative for effective and safe use of atomic energy to secure stable development of mankind and proposed that the corresponding international project be implemented with the participation of the IAEA. At the end of 2000, the IAEA established the off-budget international project INPRO on innovative nuclear reactors and fuel cycles. The content of this project is the investigation of the conditions for securing effective and safe use of atomic energy for stable development of mankind. The project evoked a strong response, and today 30 countries including the leading nuclear states and developing countries who want to know about the services of nuclear power are participants in INPRO. The project acquired international authority and is highly valued in resolutions of the general conferences at IAEA. Russia plays an important role in INPRO.The first phase of the project was completed in 2007. The content and results of the studies at this stage became the development and approval of the INPRO methodology for evaluating the correspondence of innovative nuclear power systems and their fuel cycles to the conditions and requirements for accessibility, effectiveness, and safety. The methodology developed on the basis of international collaboration, approved in the course of analysis by national experts, and approved by the community of states -participants in INPRO -represented in IAEA reflects the experience gained in 50 years of development of world nuclear power and today is being converted into a standard IAEA tool for evaluating innovative nuclear power systems.The content of the second phase of the international project INPRO are self-financed joint investigations of the actual questions concerning the development of nuclear power which are formulated by its participants. These questions include the theme proposed by our country concerning the legal and legislative basis for transportable nuclear power facilities. Transportable nuclear power facilities are those built in a factory, delivered in blocks or assembled, mounted/set on prepared sites, and removed in the same manner from these sites. The prototypes are the ...
Experience in running atomic power plants with thermal reactors has established, by analyzing the reasons for fuelelement failures, that interaction between the fuel and the cladding under unsteady conditions can lead to a breakdown of the hermetic sealing of the fuel elements due to corrosion resulting from stresses when various fission products, particularly iodine, act on the cladding [1].Investigations of iodine corrosion of claddings made of Zr-1% Nb alloy in the last few years have established that corrosion cracking is governed by such factors as the iodine concentration, the stress, temperature, the state of the internal surface, the texture of the cladding and the neutron flux [2][3][4].To predict the behavior of fuel,element claddings under emergency conditions, tests of VVI~R-t000 reactor regular fuel-element claddings made of Zr-1% Nb alloy in the presence of iodine were carried out at elevated temperatures. It was established that iodine facilitates a reduction in the cracking deformation of the claddings and the time taken for the cladding to crack in the 500-750~ range. However, its effect only manifests itself after a certain critical concentration has been exceeded [5][6][7]. According to estimates in [7] at a uranium depletion rate of 36,000 MW.day/t, the iodine content in LWR fuel elements should amount to -2.2 mg/cm 3. This value is obtained on the assumption that it is uniformly distributed over the free volume and that its relative separation is equal to the mean for gaseous fission products. However, redistribution of the fission products together with an additional increase in the separation when the fuel elements split when there is a sudden change in the power and under emergency conditions with a loss of coolant can give rise to a very high local concentration of iodine in the fuel-element claddings. At the same time one must take into account the production of a certain amount due to radiolysis of cesium iodine. The formation of cesium uranates and molybdates must also be borne in mind; this sharply increases the partial pressure of iodine, thereby facilitating the corrosion cracking of the cladding. Moreover, numerous experiments have shown that iodine and cesium separate out independently from the fuel [8].In this paper we present the results of laboratory experiments carried out to establish the temperature dependence of the initial iodine concentration at which its effect on the deformation behavior of fuel-element claddings made of Zr-1% Nb alloy is detected in isothermal tests in the 500-750~ temperature range.Isothermal tests of tubular samples of Zr-1%Nb alloy were carried out at 500-750~ when they were loaded with a constant internal pressure of argon. The samples were 125 mm long, and had an external diameter of 9.15 mm and a wall thickness of 0.72 mm. They were sealed by contact welding, pumped out and supplied with a weighed amount of crystalline iodine. The pressure of the argon f'filing was calculated from the strength of the material of the cladding so as to produce a t...
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