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Ogawa, Shinta; Hayafune, Hiroki; Tozawa, Katsuhiro; Ichimiya, Masakazu; Hayashi, Hideyuki; Mukaibo, Ryuichi
PNC TN9430 96-007, 354 Pages, 1996/07
It is required enhanced core safety characteristics, recycle cost reduction, mitigation of risk to the environment and nuclear non proliferation for the fast reactor at the commercial use age of actinide recycle. The ductless fuel assembly, which has no wrapper tube, is promising for these requirements. In this study, the thermal hydraulic and mechanical characteristics of the ductless fuel core are evaluated for 600MWe MOX core with high burnup and long operating cycle length, and conceptual structure of the ductless fuel assembly core was established. The results of the study are summarized as follows; (1)Structural of Ductless Fuel Assembly. Conceptual design of components of the ductless fuel assembly, e.g. grid spacer, tie rod, upper shielding, lower nozzle and mechanical hold down spring, were performed and conceptual structure was established. Detail study of fuel pin bundle stiffness are required in the following design study. (2)Thermo-hydraulic Characteristics of Ductless Core and Ductless Fuel Assembly. The bypass flow rate strongly depends on the gap between core region and core barrel. For this bypass flow, it is found that thermal hydraulic feasibility is expected when the gaps between core region and core barrel are decreased(
1mm). Since the core flow distribution is uniform, a coolant temperature distribution depend on the power distribution into core region. For fuel assembly, if the gaps between fuel assemblies are enlarged, the maximum sodium temperature increases (20
C/mm), therefore a proper gap design are needed. (3)Mechanical Characteristics of Ductless Core. The seismic safety of ductless core, in which a mechanical hold down are used, is assured. To decrease the impact force at spacer grid, however, some considerations on the grid design is necessary to avoid buckling. (4)Thermohydraulic Safety Characteristics. The maximum sodium temperatures are roughly evaluation under the condition of natural circulation and coolant ...
Naganuma, Masayuki; Kasai, Shigeo; Hayashi, Hideyuki; Mukaibou, Ryuichi
PNC TN9430 96-006, 157 Pages, 1996/07
As the goal requested to FBR in the future practical time, there is the improvement of economy and safety, moreover, the decrease of risk to environment by burning the long-lived nuclides and the rise of nuclear non proliferation by preventing accumulation of Pu by dealing flexibly with supply and demand of Pu will be requested. To attain these goals, it is requested that the core has the capability to receive flexibly Actinide (Minor Actinide and Pu). In other words, the concept of the core (Recycle Core) that corresponds to recycle technology (Advanced Recycle Technology), receives various fuels (including MA, low decontaminated, high Pu enriched and so on) and can permit change of nuclear property and safety characteristic by receiving such fuels is demanded. In 1995' work, to examine the concept ofthis new core, authors conducted design studies about the following contents, and evaluated characteristics of these cores. (1)Design study about MOX ductless fueled core. In adopting the ductless fuel concept, the nuclear property is improved by the increase of volume ratio of fuel, and amount of the solid waste is decreased by the deletion of wrapper tube. Thus, the economic feature is improved and the risk to environment is decreased. In such reason, we designed MOX ductless fueled core (power : 600MWe, the cycle length : 18 months, Average burnup : 150000MWd/t) as the reference core of Recycle Reactor, and estimated some performances of this core. (1)In the ductless fueled core, the volume ratio of fuel became 13% larger than the duct fueled core, and that effect made breeding ratio increase 0.08 and burnup reactivity improve about 40%. (2)By adding 3% of MA (with 20% RE of MA), Pu enrichment and breeding ratio hardly change and burnup reactivity was improved about 30%. But Doppler coefficient and Na void reactivity became about 20% worse, and this reactor got severer in respect of safety. (3)ATWS analysis was conducted to the reference core, and ...
Akatsu, Minoru; Tozawa, Katsuhiro; Watanabe, Ichiro; Ichimiya, Masakazu; Hayashi, Hideyuki; Mukaibo, Ryuichi
PNC TN9430 96-005, 237 Pages, 1996/07
In 1995, a design study on the mixed-oxide fuel core of the large breeder reactor was done to realize actinide (including minor actinide) 600MWe recycle reactor plant aiming at minimization of the radioactive waste products at the view point of not only to lighten the burden of the environment but also to utilize efficiently the resources, Study was carried out and R&D items were clarified as to the following items, as plant system design. (1)influences to the plant system from decay heat increase. (2)reactor structure concept due to adoption ductless fuel assembly concept. The study results are as follows. The coolant flow pass concept to core assemblies and the core support concept were studied by taking account of ductless core system and the large floating force on core assemblies due to ductless core system, the features of the concepts were clarified and the mechanical hold down (MHD) mechanism concept was adopted against the floating force. The characteristics of the connection between the upper internal structure and the core assemblies were studied for the large eccentricity of the two structures due to installation error, thermal expansion difference, inclination of core assemblies, etc. The connection that were led by MHD was guessed to be done with no large problem by special connection procedure. The reactor auxiliary cooling system capacity of 16MW a loop is sufficient to remove core decay heat to maintain the integrity of the coolant boundary structure. The heat removal characteristics under natural convection circulation coolant flow is confirmed to be superior than ducted core plant because of the lower pressure drop property of the ductless core plant. The cask car type fuel handling system was selected as referenceex-vessel fuel handling system. Because the cask car type system was able to simplify the fuel handling system by the in-line configuration of fuel handling facilities. The decay heat of ductless spent fuel assembly in sodium pot ...
Kasai, Shigeo; Tozawa, Katsuhiro; Akatsu, Minoru; Ogawa, Shinta; Watanabe, Ichiro; Hayafune, Hiroki; Naganuma, Masayuki; Ichimiya, Masakazu; Hayashi, Hideyuki; Mukaibou, Ryuichi
PNC TN9430 96-004, 152 Pages, 1996/07
Authors are studying the Actinide Recycle Fast Breeder Reactor (named ARFBR in this paper), which contribute to the reduction of burdens to environments and to enhance the capability to prevent the nuclear proliferation as the entire nuclear recycle system (named Advanced Fuel Recycling FBR system (AFRFS) in this paper), and also investigating the ARTR for developing the ARFBR. The investigation of the ARTR consists of the design study of the ARTR and R&Ds of key technology existing in ARTR concept. The conceptual design study of the ARTR is planed to be conducted for 2 years from 1995 to 1996 as first stage. 1995's design study have been performed with drawing over all plant concept with supposing various tests in reactor and usage of reactor. Followings are distinctive feature of 1995's design study. (1)Maximum reactor power is 400MWt with about 1.6m diameter irradiation (burning) cores, which are designed to be operated up to 150GWd/t as average burn up. Maximum core diameter is about 2.5m for low power nuclear physics tests which are designed to be able to estimate characteristics of large scale core by using the test results. (2)Mixed oxide (MOX) and Mixed nitride (MN) core is designed respectively to be able to be used for static nuclear physics test, for nuclear and thermal transient test, and for full power irradiation or burning test. Each core is designed to terminate ATWS events passively, with using GEM for MOX core and with using spectral adjustment for MN core. (3)Fuel assembly is employed ductless type which is a promising candidate for the ARFBR. Sizing of a fuel assembly is determined in basis on MOX fuel design because MOX fuel pin length covers MN fuel pin which accommodates lesser FP gases because of its lower temperature. Fuel assembly is managed to be held by hydraulic force in case of freeing mechanical stopper by requirement of testability. (4)Reactor assembly is designed based on so called Head Access Loop Type Reactor. Main changes ...
; ; ; ;
PNC TN9410 94-173, 34 Pages, 1994/05
PNC made design studies on loop type FBR plants:a 600 MWe class in '91, and a 1300 MWe class in '93 both with the "head access" primary piping system. This paper focuses on the features of the smaller plant at first and afterwards on the extension to the larger one. The contents of the paper consist of R/V wall protection mechanism, primary piping circuit, secondary piping circuit, plant layout and then, discusses the extension of the applicability of the wall protection mechanism, primary piping and equipment to the larger plant. Through these studies PNC reached the conclusion that the "head access" concept is applicable to all cases of FBRs from the demonstration to commercial phase.
Enerugi Foramu, 38(448), p.80 - 81, 1990/00
*; Aratono, Yasuyuki
Nihon Genshiryoku Gakkai-Shi, 31(7), p.802 - 804, 1989/07
no abstracts in English
*; *; *; Inoue, Teruji*; *; *; *
PNC TN941 82-117, 950 Pages, 1982/05
The reactor power of the Experimental Fast Reactor Joyo was raised to 50 MW in July, 1978 and then to 75 MW in July, 1979. This report discribes the temperature distributions of the rotating plugs of Joyo measured from April, 1978 through December, 1981. The following results were obtained. (1)The overall temperature distributions of the large rotating plug the samll rotating plug, and the upper-core-structure have a tendency to become higher in this order and become steady state within about a week. (2)The temperature distributions of the rotating plugs have no tendency to change periodically within either a few days or longer period, and unusual temperature distributions due to imbalanced sodium vapor deposition have not been detected.
*
PNC TN960 80-11, 391 Pages, 1980/12
The author was assigned to the FFTF project under an agreement between the Department of Energy of the U.S. and the Power Reactor and Nuclear Fuel Development Corporation of Japan. This report introduces the refueling system of the FFTF and covers the work done by the author as an assignee at the FFTF organization. Also included are reports on visits to Argonne National Laboratory (East and West), Westinghouse Advanced Reactors Division, Los Alamos Scientific Liboratory and Atomics International.
*; *
Nihon Genshiryoku Gakkai-Shi, 5(7), p.601 - 608, 1963/00
no abstracts in English
Naito, Keiji; *; *
Nihon Genshiryoku Gakkai-Shi, 4(11), p.754 - 758, 1962/00
no abstracts in English
; Naito, Keiji; *
Nihon Genshiryoku Gakkai-Shi, 4(2), p.111 - 117, 1962/00
no abstracts in English
Nakajima, Ichiro; Sasao, Nobuyuki; Yamana, Hajime; Kashihara, Hidechiyo;
Bunri, Sakugen Joho Kokan Kaigi, ,
None
Sangyo To Kankyo, 14(6), 56 Pages,
