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[en] On the path to deployment of any reactor, modeling tool verification and validation is a key step. Fluoride-Salt-Cooled High Temperature Reactors (FHR) pose challenges to neutronics modeling and simulation tools due to several design features of the reactor type. This paper presents a categorized list of phenomena that pose challenges to FHR modeling using current neutronics tools. These phenomena are presented in four categories: Fundamental Cross Section Data, Material Composition, Computational Methodology, and General Depletion. A short path forward for these phenomena is also presented. In addition, a discussion of the resulting gaps in current codes is presented.
Journal
[en] Preliminary results of the dynamic analysis of a two-fluid molten-salt breeder reactor (MSBR) system are presented. Based on an earlier work on the preliminary dynamic model of the concept, the model presented here is nonlinear and has been revised to accurately reflect the design exemplified in ORNL-4528. A brief overview of the model followed by results from simulations performed to validate the model is presented. Simulations illustrate stable behavior of the reactor dynamics and temperature feedback effects to reactivity excursions. Stable and smooth changes at various nodal temperatures are also observed. Control strategies for molten-salt reactor operation are discussed, followed by an illustration of the open-loop load-following capability of the molten-salt breeder reactor system. It is observed that the molten-salt breeder reactor system exhibits “self-regulating” behavior, minimizing the need for external controller action for load-following maneuvers
Journal
Nuclear Engineering and Technology; ISSN 1738-5733; 
; v. 49(5); p. 887-895
; v. 49(5); p. 887-895
[en] The Molten Salt Fast Reactor (MSFR) with its liquid circulating fuel and its fast neutron spectrum calls for a new safety approach including technological neutral methodologies and analysis tools adapted to early design phases. In the frame of the Horizon2020 program SAMOFAR (Safety Assessment of the Molten Salt Fast Reactor) a safety approach suitable for Molten Salt Reactors is being developed and applied to the MSFR. After a description of the MSFR reference design, this paper focuses on the identification of the Postulated Initiating Events (PIEs), which is a core part of the global assessment methodology. To fulfil this task, the Functional Failure Mode and Effect Analysis (FFMEA) and the Master Logic Diagram (MLD) are selected and employed separately in order to be as exhaustive as possible in the identification of the initiating events of the system. Finally, an extract of the list of PIEs, selected as the most representative events resulting from the implementation of both methods, is presented to illustrate the methodology and some of the outcomes of the methods are compared in order to highlight symbioses and differences between the MLD and the FFMEA
Journal
Nuclear Engineering and Technology; ISSN 1738-5733; ; v. 51(4); p. 1024-1031
; v. 51(4); p. 1024-1031
[en] Creation fast critical molten salt reactor for burning-out minor actinides and separate long-living fission products in the closed nuclear fuel cycle is the most perspective and actual direction. The reactor on melts salts - molten salt homogeneous reactor with the circulating fuel, working as burner and transmuter long-living radioactive nuclides in closed nuclear fuel cycle, can serve as an effective ecological cordon from contamination of the nature long-living radiotoxic nuclides. High-flux fast critical molten-salt nuclear reactors in structure of the closed nuclear fuel cycle of the future nuclear power can effectively burning-out / transmute dangerous long-living radioactive nuclides, make radioisotopes, partially utilize plutonium and produce thermal and electric energy. Such reactor allows solving the problems constraining development of large-scale nuclear power, including fueling, minimization of radioactive waste and non-proliferation. Burning minor actinides in molten salt reactor is capable to facilitate work solid fuel power reactors in system NP with the closed nuclear fuel cycle and to reduce transient losses at processing and fabrications fuel pins. At substantiation MSR-transmuter/burner as solvents fuel nuclides for molten-salt reactors various salts were examined, for example: LiF - BeF2; NaF - LiF - BeF2; NaF-LiF ; NaF-ZrF4 ; LiF-NaF -KF; NaCl. RRC 'Kurchatov institute' together with other employees have developed the basic design reactor installations with molten salt reactor - burner long-living nuclides for fluoride fuel composition with the limited solubility minor actinides (MAF3 < 2 mol %) and have estimated its basic characteristics. On the basis of these data employees RRC KI and VNIPIET carry out conceptual binding reactor installations with molten salt reactor - burner to the project of a factory on processing 500 tons spent fuel of reactors of type WWER-1000 in a year. During a settlement-experimental research in RRC KI it is shown, that fluoride fuel composition with high solubility minor actinides (MAF3 > 10 mol %) allows to develop in some times more effective molten salt reactor with fast neutron spectrum - burner/ transmuter of the long-living radioactive waste. In high-flux fast reactors on melts salts within a year it is possible to burn ∼300 kg minor actinides per 1 GW thermal power of reactor. The technical and economic estimation given power-technological complex shows on economic efficiency of use such burner/transmuter. After separation from spent fuel power reactors minor actinides go on burning out in molten salt reactor. The offered concept power-technological complex with high-flux fast reactor on melts salts, intended for burning out and transmutation long-living radiotoxic nuclides, at practical realization will allow minimizing quantity of the long-living radioactive waste in system of a nuclear power. Accommodation of such reactors at the enterprises of a fuel cycle will provide with their energy and will facilitate the decision of a problem of radioactive waste management with the minimal losses. Small share MSR (5-7) % from full electric power in structure of the future nuclear power provides practically full burning of all minor actinide (Authors)
Source
Vidovszky, Istvan (Kiadja az MTA KFKI Atomenergia Kutatointezet, H-1525 Budapest 114, P.O.Box 49 (Hungary)); VUJE, Inc., 918 64 Trnava (Slovakia); KFKI Atomic Energy Research Institute, Reactor Analysis Laboratory, H-1525 Budapest 114, POB 49 (Hungary); Russian Research Center 'Kurchatov Institute', 1, Kurchatov sq., 123182 Moscow (Russian Federation); State Scientific and Technical Centre on Nuclear and Radiation Safety, 35-37 Radgospna street, 03142 Kyiv-142 (Ukraine); Paks NPP Ltd., 7031 Paks (Hungary); Nuclear Research Institute Rez plc, CZ-250 68 Husinec-Rez, cp.130 (Czech Republic); Skoda JS a.s., Orlik 266, 31606 Plzen (Czech Republic); Fortum Nuclear Services Ltd., Rajatorpantie 8, Vantaa, POB 10-FIN-00048 FORTUM (Finland); Kozloduy NPP plc, Kozloduy 3321 (Bulgaria); FSUE OKB 'GIDROPRESS', 142103 Moscow region, 21 Ordzhonikidze street, Podolsk (Russian Federation); 492 p; ISBN 963-372-636-5; ; Nov 2007; p. 775-788; 17. Atomic Energy Research Symposium on WWER Physics and Reactor Safety; Yalta, Crimea (Ukraine); 23-29 Sep 2007; Also available from VUJE, Inc., Okruzna 5, 918 64 Trnava (SK); 5 refs.; 7 figs.; 9 tabs.
; Nov 2007; p. 775-788; 17. Atomic Energy Research Symposium on WWER Physics and Reactor Safety; Yalta, Crimea (Ukraine); 23-29 Sep 2007; Also available from VUJE, Inc., Okruzna 5, 918 64 Trnava (SK); 5 refs.; 7 figs.; 9 tabs.
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