[en] Starting from the time-dependent three-dimensional two-group diffusion equations for a bare homogeneous critical reactor, it is shown that the fluctuations of the neutron population can be uniquely separated into a local and a global component with each component satisfying a second-order differential equation. It is shown that under certain limitations, the two-group treatment of the neutron noise and the subsequent derivation of the two components is equivalent to the one-group theory in which the slowing down of the fast neutrons is taken into account through an appropriately chosen slowing down kernel. The theory so developed, is applied in order to investigate the local component of the neutron noise induced by a randomly vibrating infinitely thin absorber in a two dimensional cylindrical reactor and the neutron noise due to axially propagating perturbations of the moderator density, in a multi-channel model of a three-dimensional slab reactor. (author)

[en] AHR (Aqueous Homogeneous Reactor) is belong into the homogeneous reactor group designed to use the fluid fuel with the aims not only for getting the chain reaction but also for radioisotope production. The use of fluid fuel gives the possibility to produce the radioisotope in on power condition, low reactor power, low temperature and pressure, and relatively small size of nuclear reactor. In the development of homogeneous reactor (HR) is also designed for electricity generation. Some issues related to material corrosion, fission product gas release, are still in questions. To support the oversight of this technology needs to be carefully reviewed in field of safety, security, and safeguards. (author)

[en] This paper describes the evolution of a series of point kinetics models used to simulate a conceptual Aqueous Homogeneous Reactor (AHR). This reactor is made up of a 180 l tank of low-enrichment uranyl nitrate solution with embedded cooling coils and a mechanism for the removal of radiolytic gases. Each iteration of the model included more physical processes allowing a wider range of scenarios to be studied with increasing physical accuracy. For instance, the second iteration included phenomena linked to boiling whereas the third included phenomena linked to the pressure inside the reactor vessel. Several general trends were observed in the results of the models. Firstly, power excursions were limited in scope in all physically credible scenarios due to the strong negative feedbacks associated with AHRs. Oscillations in power were common in response to a change in reactivity but were strongly damped and, in the absence of a driving oscillation, the power tended towards an equilibrium value which was not very much larger than the reactor's operating power in a matter of tens of minute. The simulated failure of the coolant flow or gas management system caused no power excursion

[en] The FAKTOR-3K fast-response program complex developed for calculation of homogeneous uranium aqueous reactor characteristics is described. The complex includes the block of initial data input, the KONST program for calculation of the blocked microscopic and macroscopic constants for different physical zones and the FAKTOR-3 program for solving two-dimensional equation of a reactor in the three-group diffusion approximation with obtained result printing. The blocked microconstant preparation procedure is based on the method automatically accounting for variations in the cross section shielding coefficients with reactor core composition change. Two-dimensional calculation is made by the method of h-factorization. The programs are written in the FORTRAN-4 language for the ES-1030 computer. On the base of the analysis of results of effective neutron multiplication factor calculations made for cylindrical assemblies with different fuel enrichment the conclusion is made that the FAKTOR-3K complex permits to predict critical parameters of fuel assemblies containing uranium solutions of high and low enrichment with error no more than +-2%

No abstract available

[en] Aqueous Homogeneous Reactor is a nuclear reactor with fuel solution and homogeneously mixed with a moderator and being developed as a means to produce medical isotopes. To perform its function of producing radioisotope, AHR will require radioisotope separation facility. In general, radioisotope separation facilities connected with AHR, will consist of several parts, such as extraction section, waste and gas management section, iodine separation section, purification section, delivery section and also the connecting sections. Results of the assessment shows that several safety related things needs to be considered for the radioisotopes separation facility of AHR. Exposure to high radiation from the fuel solution that will enter radioisotopes separation facilities will need a shielded room to hold or reduce exposure to workers. The use of materials particularly on the piping must be resistant to corrosion or against radiation. The potential leak or absorption gas saturation of iodine and other fission products also needs to be considered. It should also be noted related waste generated from this facility such as fuel solution, absorption materials, fission product gases, pipes or other process materials. (author)

[en] The decontamination and disposition of the KEWB facilities, Buildings 073, 643, 123, and 793, are complete. All of the facility equipment, including reactor enclosure, reactor vessel, fuel handling systems, controls, radioactive waste systems, exhaust systems, electrical services, and protective systems were removed from the site. Buildings 643, 123, and 793 were completely removed, including foundations. The floor and portions of the walls of Building 073 were covered over by final grading. Results of the radiological monitoring and the final survey are presented. 9 tables, 19 figures

No abstract available

[en] In 2013 a state-owned company has submitted to BAPETEN the plans to build a non-power reactors to produce radioisotope ⁹⁹Mo. The reactor which will be built is a liquid-fueled reactors/Aqueous homogeneous Reactor (AHR). AHR can use UO₂(NO₃)₂ or UO₂SO₄ as fuel and ⁹⁹Mo produced by separating it from the fuel solution. For regulating the design, construction, and operation of non-power reactors BAPETEN been issued regulations governing such matters using the IAEA safety Standards document as guidelines. Regulations issued generally consider solid fuel reactor. It is therefore necessary to study the applicability of the BAPETEN Chairman regulations to be used in regulating the construction of AHR. Initial assessment has shown that there is a need to set more specific safety provisions to regulate the activities of design, construction, and operation of the AHR considering the difference in the phenomena that occur therein. (author)

No abstract available