; Tozawa, Katsuhiro; Kakehi, Isao
JNC TN9400 2001-094, 114 Pages, 2001/07
This report describes accomplishment of development of a cathode processor calculation code to simulate the mass and heat transfer phenomena with the distillation process and parameter survey using developed analytical model for cooling behavior of the pyrochemical process cell on personal computers. The pyrochemical process using molten salt electrorefining would introduce new technologies for new fuels of particle oxide, particle nitride and metallic fuels. Evaporation calculations using cathode processor calculation code with distillation process, which was developed in 2000, were evaluated. By selecting proper input data (time step, mesh size etc.), the results showed that the present code agreed well for the evaporation rate of cadmium., and the capability of the distillation process design and simulation with the code has been confirmed. Parameter surveys using developed analytical model were performed for the purpose of reflection of cooling system design of the pyrochemical process cell. 4 cases of cooling flow patterns were surveyed at the normal and low flow rate conditions. From the result of parameter surveys, It was shown that the cooling pattern with direct cooling for heating facilities in the lower cen and balk cooling for upper cell is desirable.
Kakehi, Isao; Yoshiuji, Takahiro*
JNC TN9400 2001-054, 144 Pages, 2001/03
This report describes accomplishment of simulations of maintenance methods for the pyrochemical process by using virtual engineering models. The pyrochemical process using molten salt electrorefining would introduce new technologies for new fuels of particle oxide, particle nitride and metallic fuels. This system is a batch treatment system of reprocessing and re-fabrication, which transports products of solid form from a process to next process. The maintenance of this process needs remote control, because the process equipments are arranged in a large hot cell. In this study, a simulation code system has been prepared, which provides virtual engineering environment to evaluate the maintenance methods, which we have planned for the pyrochemical process. The simulation study has been conducted to evaluate the required system functions of the maintenance, including methods procedure, handling system, equipments, and remote control. The simulation study has been conducted in the case of the maintenance of molten salt electrorefiner. As a result of simulation of the process maintenance, which we have designed, the realistic maintenance system for the pyrochemical process have been shown. The issues for the system development have been pointed out.
JNC TN9400 2000-054, 84 Pages, 2000/04
This report describes accomplishment of the study on the quality of vipac (vibro-packed) oxide fuel obtained by pyrochemical processing (molten salt electrolytic processing). This study is intended to contribute to the design study of the pyro-reprocessing-vipac fuel recycling system of oxide fuel. In this study, vibro-packing experiment has been conducted using granular U0 obtained by molten salt electrolytic processing (cold experiment). The oxide pyro process developed by Research lnstitute of Atomic Reactors (RIAR) is the method in which the sintered oxide is electrically deposited on the cathode at approximately 600C. 0xide granules for vipac fuel are obtained by crushing the oxide deposited on the cathode. This process is also developed as recycle process because it is capable of FP separation. Also in Japan, this process is studied as one of the new FBR fuel recycling systems. ln this study, we made an effort to clarify the mechanisms of vibro-packing of the electrically obtained granules, which influence on the effective parameters of vibro-packing density and fuel particles size distribution in the fuel cladding in case of non-sphere particles of the granules. As a result of the study, smear density of 75% and almost uniform distribution of U0 particles have been taken in the experiment, and much knowledge for the improvement of the vibro-packing quality has been found. And the possibility of the smear density over 80% and the uniform distribution of U0 particles has been suggested in this study.
Kakehi, Isao; Tozawa, Katsuhiro; ; ; *
JNC TN9400 2000-053, 99 Pages, 2000/04
This report describes accomplishment of simulations of Pyrochemical Process Operation by using virtual engineering models. The pyrochemical process using molten salt electrorefining would introduce new technologies for new fuels of particle oxide, particle nitride and metallic fuels. This system is a batch treatment system of reprocessing and re-fabrication, which transports products of solid form from a process to next process. As a result, this system needs automated transport system for process operations by robotics. ln this study, a simulation code system has been prepared, which provides virtual engineering environment to evaluate the pyrochemical process operation of a batch treatment system using handling robots. And the simulation study has been conducted to evaluate the required system functions, which are the function of handling robots, the interactions between robot and process equipment, and the time schedule of process, in the automated transport system by robotics. As a result of simulation of the process operation, which we have designed, the automated transport system by robotics of the pyrochemical process is realistic. And the issues for the system development have been pointed out.
Tozawa, Katsuhiro; ; Kakehi, Isao
JNC TN9400 2000-052, 110 Pages, 2000/04
This report describes accomplishment of development of a cathode processor calculation code to simulate the mass and heat transfer phenomena with the distillation process and development of an analytical model for cooling behavior of the pyrochemical process cell on personal computers. The pyrochemical process using molten salt electrorefining would introduce new technologies for new fuels of particle oxide, particle nitride and metallic fuels. The cathode processor calculation code with distillation process was developed. A code validation calculation has been conducted on the basis of the benchmark problem for natural convection in a square cavity. Results by using the present code agreed well for the velocity-temperature fields, the maximum velocity and its location with the benchmark solution published in a paper. The functions have been added to advance the reality in simulation and to increase the efficiency in utilization. The test run has been conducted using the code with the above modification for an axisymmetric enclosed vessel simulating a cathode processor, and the capability of the distillation process simulation with the code has been confirmed. An analytical model for cooling behavior of the pyrochemical process cell was developed. The analytical model was selected by comparing benchmark analysis with detailed analysis on engineering workstation. Flow and temperature distributions were confirmed by the result of steady state analysis. In the result of transient cooling analysis, an initial transient peak of temperature occurred at balanced heat condition in the steady-state analysis. Final gas temperature distribution was dependent on gas circulation flow in transient condition. Then there were different final gas temperature distributions on the basis of the result of steady-state analysis. This phenomenon has a potential for it's own metastable condition. Therefore it was necessary to design gas cooling flow pattern without ...
Kakehi, Isao; Nakabayashi, Hiroki
JNC TN9400 2000-051, 237 Pages, 2000/04
In this study, we have proposed the concept of safety systems (solutions of safety problems) in pyrochemical reprocessing systems (lt consists of pyrochemical reprocessing methods and the injection casting process for the metal fuel fabrication, or vibro-packing process for the oxide fuel fabrication.) which has different concept from the existing PUREX reprocessing method and pellet fuel fabrication process. And we performed its safety evaluations. FoIlowing the present Japanese safety regulations for reprocessing facilities, we pointed out functions, design requirements and equipments relating to its safety systems and picked up subjects. For the survey of safety evaluations, we first selected anticipated events and accident events, and second by evaluated 6the correspondence of the limitation of the public exposure to the accidents above, by using two parameters, the safety design parameter (the filter performance to confine radioactive matelials) and the leak inventory of radioactivities, and last by picked up its problems. ln addition to the above evaluations we performed basic criticality analyses for its systems to utilize these results for the design and evaluation of the criticality safety management system. Thus this study specified the concept of safety systems for pyrochemical reprocessing processes and then issues in order to establish safety design policies (matters which must consider for the safety design) and guides and to advance more definite safety design.
; Kakehi, Isao; Moro, Satoshi; Yonezawa, Shigeaki; ; Tozawa, Katsuhiro
Proceedings of International Conference on Future Nuclear Systems (GLOBAL'99), 0 Pages, 1999/00
; Kakehi, Isao; Moro, Satoshi; ; ; ;
JNC TN9400 98-003, 422 Pages, 1998/10
Advanced recycle system engineering group of OEC has being carried out a design study of the advanced nuclear fuel recycle system using molten salt (electro-metallurgical process). This system is aiming for improvements of fuel cycle economy and reduction of environmental burden (MA recycles, Mimmum of radioactive waste disposal), and also improvement of safety and nuclear non-proliferation. This report describes results of the design study that has been continued since December 1996. (1)A design concept of the advanced nuclear fuel recycle system, that is a module type recycle system of pyrochemical reprocessing and fuel re-fabrication was studied. The module system has advantage in balance of Pu recycle where modules are constructed in coincidence with the construction plan of nuclear power plants, and also has flexibility for technology progress. A demonstration system, minimum size of the above module, was studied. This system has capacity of 10 tHM/y and is able to demonstrate recycle technology of MOX fuel, metal fuel and nitride fuel. (2)Each process of the system, which are pyrochemical electrorefining system, cathode processor, de-cladding system, waste disposal system, etc., were studied. In this study, capacity of an electrorefiner was discussed, and vitrification experiment of molten salt using lead-boric acid glass was conducted. (3)A hot cell system and material handling system of the demonstration system was studied. A robot driven by linear motor was studied for the handling system, and an arrangement plan of the cell system was made. Criticality analysis in the cell system and investigation of material accountancy system of the recycle plant were also made. This design study will be continued in coincidence with design study of reactor and fuel, aiming to establish the concept of FBR recycle system.
; Moro, Satoshi; ; Kakehi, Isao; ;
PNC TN9410 98-033, 284 Pages, 1998/03
System engineering division of OEC has being carried out a design study of the advanced nuclear fuel recycle system using electro-metallurgical process, aiming for improvements in safety, reliability, economy and a1so in environmental burden and nuclear non-proliferation. But the public criticism against nuclear power is more severe recently, and the situation is changing as seeing in the conclusion of the round-table conference on FBR. The researcher's meetings, in which researchers in PNC and from other organizations attended, were held during December, 1997 and March, 1998 in order to discuss on the advanced nuclear fuel recycle system and technology for FBR to be aimed in the future, and how to execute its research & development, etc. The conclusions of this meeting are as follows: (1)The future advanced FBR fuel cycle system shall be the system which has high potential for maximum utilization of uranium resources, and also for revolutionary improvements of economy, safety, environmental burden, etc. so as to be accepted in the society. (2)Regarding to the process of the future fuel eycle system, electro-metallurgical process that is able to apply for reprocessing of different types of fuel (oxide, metal and nitride) and is flexible for technical progress is recommended. Research & development of this system and technology shall be carried out. (3)The mission of PNC (new organization) is to select the most appropriate advanced FBR fuel cycle system from the viewpoint of the long-term FBR age in the future, and to conduct development of its system. It is expected for the new organization to execute its research and development steadily in cooperation with other research institutes, etc. under the nation-wide assessment and agreement. According to the above conclusions, the system engineering division will enhance the design study of the advanced FBR fuel cycle system and establish the definite concept of the system in cooperation with concerned in and ...
Kakehi, Isao; ; ; ; Yonezawa, Shigeaki; Takahashi, Katsuro
Proceedings of International Conference on Future Nuclear Systems (GLOBAL'97), 0 Pages, 1997/10
Kakehi, Isao; ; ; ; ; Kajitani, Yukio;
PNC TN9410 97-015, 382 Pages, 1996/12
For the purpose of developing the future nuclear fuel recycle system, the design study of the advanced nuclear fuel recycle system is being conducted. This report describes intermediate accomplishments in the conceptual system study of the advanced nuclear fuel recycle system. Fundamental concepts of this system is the recycle system using molten salt which intend to break through the conventional concepts of purex and pellet fuel system. Contents of studies in this period are as follows, (1)feasibility study of the process by Cd-cathode for nitride fuel (2)application study for the molten salt of low melting point (AlCl+organic salt)(3)research for decladding (advantage of decladding by heat treatment)(4)behavior of FPs in electrorefinning (behavior of iodine and volatile FP chlorides, FPs behavior in chlorination) (5)criticaliy analysis in electrorefiner (6)drawing of off-gas flow diagram (7)drawing of process machinery concept (cathode processor, vibration packing) (8)evaluation for the amounts of the high level radioactive wastes (9)quality of the recycle fuels (FPs contamination of recycle fuel) (10)conceptual study of in-cell handling system (11)meaning of the advanced nuclear fuelrecycle system. The conceptual system study will be completed in describing concepts of the system and discussing issues for the developments.
Kakehi, Isao*; Tani, Saburo*; Fujii, Eiji*; Okano, Hideharu*; Endo, Kinji*; Kawada, Toshiyuki*; Ogata, Keizo*
PNC TN251 77-07, 72 Pages, 1977/02
Changes in the reactor power result in relative movements between the fuel rod bundle and grid spacers, due to thermal expansion of fuel rods. Contact load, which is caused by deformation of fuel rods or axial alignment of grid spacers, is set up on the contact surfaces. From this reason, changes in reactor power are the cause of galling between fuel rods and grid spacers. In this work, wear between fuel rods and grid spacers in sodium was evaluated quantitatively under simulated reactor conditions, and a mock-up test in sodium was carried out in order to evaluate designs of the fuel rod, grid spacers, and grid spacer mounting methods.