RESEARCH REACTOR "RA" AT "VINČA" INSTITUTE OF NUCLEAR SCIENCES
by Milena MATAUŠEK

Abstract: During the visit of representatives of the VINČA Institute of Nuclear Sciences to the International Atomic Energy Agency (IAEA) they were requested to prepare a short overview of the situation with the research reactor RA. This paper, presenting chronologically main events of interest for the present status of the reactor and describing the main reactor features and systems, with emphasis on fuel handling and fuel inventory, will be used by IAEA to initiate a procedure of establishing an international safety advisory group to visit the VINČA Institute. Since in the present political situation only humanitarian international support and assistance can be expected, this paper particularly points out the safety aspects of the present and future reactor status.

Key words: research reactors, research reactor RA, re search reactor safety

SAFETY ANALYSIS OF THE PRESENT STATUS OF THE RESEARCH REACTOR "RA" AT "VINČA" INSTITUTE
by Valerije JOVIĆ , Larisa JOVIĆ, Djordjina MILOVANOVIĆ, Zoran ŽIVOTIĆ

Abstract: Safety analysis of the nuclear facility which has been out of work for a long time and whose future is not defined at the present moment, can not be connected to the usual, normatively regulated system analysis procedure in both operational and accidental regimes. Therefore, the safety analysis of the present status of the reactor RA is related to system and components analysis which, in present conditions maintain their nuclear functions operational. In the first place, it refers to components and equipment in which radioactive radiation generation still exists and to installations and equipment maintaining radiation level below permitted limit. In the context of the analysis the following areas are being covered: present status characteristics, accidental events while operating period from 1959. to 1984., nuclear fuels and radioactive waste inventory, basic characteristics and status of safety-related systems and equipment, radiation protection, potential accident analysis at present status of the reactor RA, potential accidental situations due to natural events (earthquakes, water flood) or man-induced events and security.

Key words: research reactor, reactor RA in VINČA, safety analysis

Note: Full text published in Serbian

ESTIMATED VALUE OF THE NUCLEAR RESEARCH REACTOR "RA" AT "VINČA" INSTITUTE
by Milan JOVANIĆ, Obrad ŠOTIĆ, Gordana TODOROVIĆ

Abstract: The RA nuclear research reactor in VINČA Institute is a significant scientific, technological and economic national resource. Its initial value has been diminished during many years of exploitation, but enlarged also through the modernization of reactor systems and construction of some new ones. Assuming that the basic installation has lost no more than 50% of its initial value, and taking into account adequate economic parameters, it has been estimated that the present value of the RA reactor exceeds 34.000.000 USD.

Key words: research nuclear reactor, reactor RA, economic analysis, reactor costs

Note: Full text published in Serbian

FINAL DISPOSAL OF LOW AND INTERMEDIATE LEVEL RADIOACTIVE WASTE MATERIALS
by Ilija PLEĆAŠ

Abstract: Basic principles of treatment, disposal of low and intermediate level radioactive waste generated in nuclear power plants and other sources, such as medicine and scientific institutions, are presented in this review article. Summary is given of final disposal of low and intermediate level radioactive waste materials worldwide, emphasizing the basic principles of disposal in natural geological formations, as well as in artificially made engineering shallow land concrete disposal system. Finally, waste literature survey in this field, relevant for this mater is presented.

Key words: storage, conditioning, final disposal, specific activity contamination, emitters, radioisotopes, leaching, matrix, radionuclides

Note: Full text published in Serbian

SOLUTION OF MODIFIED NEUTRON TRANSPORT EQUATION IN PLANE GEOMETRY
by Rodoljub SIMOVIĆ

Abstract: Neutron transport equation was formulated for universal anisotropic scattering function with integration over variable m carried out in segment [0,1] instead of segment [-1,1]. A modified system of DPN equations was derived and solved by applying flux expansion in double Legendre polynomials over variable m. As an example, case of neutron isotropic scattering was treated in detail and Green functions for infinite medium were computed. The application of the eighth order analytical approximation achieved the accuracy to the unit on the sixth significant digit in the whole range of parameter c, angle cosine m  and distances x up to ten optical lengths from the neutron source.

Key words: transport equation, anisotropic scattering, DPN method, infinite medium Green function, neutron