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Patent
China General Nuclear Power Group and China Nuclear Power Technology Research Institute | Date: 2013-03-04

A new, improved grid spacer for a nuclear fuel assembly is provided, comprising several straps which intersect each other alternatively to form a plurality of grid cells and fuel rods reside in some of the grid cells; the grid spacer further comprises mixing elements set at the corner of the grid cells in which the fuel rods have resided; wherein the mixing element comprises a mixing vane stretching towards the direction of the fuel rod and a flow funnel set on the bended edge of the mixing vane continuously and extending towards adjacent grid cells; the mixing vane and the flow funnel set across two sides of two adjacent grid cells respectively, and the flow funnel introduces the coolant in the grid cell at its side to the mixing vane, then the mixing vane introduces the coolant to the grid cell at its own side.


Patent
China Nuclear Power Technology Research Institute and China General Nuclear Power Group | Date: 2013-09-25

The present invention relates to a bottom nozzle filtering device and a debris-preventive bottom nozzle that can be used for a light water reactor (LWR) nuclear fuel assembly. The bottom nozzle filtering device includes a plurality of successively spliced unit plates; a through flow channel is formed between the spliced adjacent unit plates; the flow channel includes a plurality of spaced straight-section flow inlets, and a plurality of spaced straight-section flow outlets, as well as a flow subchannel communicating with the straight-section flow inlets and the straight-section flow outlets; the outlet section of each straight-section flow inlet in the middle splits respectively into two flow subchannels, and the inlet section of each straight-section flow outlet in the middle communicates respectively with the two flow subchannels. The flow direction of the coolant is controlled by the straight-section flow inlet, the straight-section flow outlet, the flow subchannel, etc. to prevent unnecessary eddies forming, making the pressure loss effectively controlled; after a large size debris is stopped, the flow enters the flow subchannel to be filtered again, realizing staged filtering, thus improving the filtering effect.


Patent
China Nuclear Power Engineering Co., China General Nuclear Power Group and China Nuclear Power Technology Research Institute | Date: 2010-05-21

A method for joint configuration of nuclear power plant fuel includes the following steps: (S1) for at least one operating unit, based on an equilibrium cycle or transition cycle reactor core design, at least one new fuel element is added to at least one operating unit; (S2) after running a combustion cycle, and on basis of the new fuel elements in step (S1), more first spent fuel elements are obtained from the at least one operating unit than are obtained from the equilibrium cycle or transition cycle reactor core design, and said first spent fuel elements are kept in reserve; (S3) for at least one new starting unit, a scheduled number of new fuel elements, as well as the first spent fuel elements obtained for reserve in step (S2), are set in the first reactor cores of at least one new starting unit.


Patent
China Nuclear Power Technology Research Institute and China General Nuclear Power Group | Date: 2016-10-26

A bottom nozzle (100) includes a skirt (10), support blocks (20), transverse blades (30) and longitudinal blades (40). The skirt (10) is a hollow structure and a bottom thereof is provided with corner legs (11) which are protruded downwards, a cavity is defined in the hollow structure, the transverse blades (30) are configured in the cavity, the longitudinal blades (40) are configured in the cavity, the transverse blades (30) and longitudinal blades (40) are firmly connected with the skirt (10), projections of the transverse blades (30) and the longitudinal blades (40) in a level plane are intersectant to form interleaved grids, and the support blocks (20) run through and are fixed on the transverse blades (30) and the longitudinal blades (40). In such a way, the bottom nozzle (100) forms a three-dimensional gridded water passage, thereby improving the filter capacity and generating small water pressure drop.


Patent
China Nuclear Power Engineering Co., China Nuclear Power Technology Research Institute and China General Nuclear Power Group | Date: 2012-04-04

A method for joint configuration of nuclear power plant fuel includes the following steps: (S1) for at least one operating unit, based on an equilibrium cycle or transition cycle reactor core design, at least one new fuel element is added to at least one operating unit; (S2) after running a combustion cycle, and on basis of the new fuel elements in step (S1), more first spent fuel elements are obtained from the at least one operating unit than are obtained from the equilibrium cycle or transition cycle reactor core design, and said first spent fuel elements are kept in reserve; (S3) for at least one new starting unit, a scheduled number of new fuel elements, as well as the first spent fuel elements obtained for reserve in step (S2), are set in the first reactor cores of at least one new starting unit.


Wang S.,China Nuclear Power Technology Research Institute
Proceedings - 2011 2nd International Conference on Innovations in Bio-Inspired Computing and Applications, IBICA 2011 | Year: 2011

Traditional machine learning methods for intrusiondetection can only detect known attacks since these methodsclassify data based on what they have learned. New attacks areunknown and are difficult to detect because they have notlearned. In this paper, we present an improved k-meansclustering-based intrusion detection method, which trains onunlabeled data in order to detect new attacks. The result ofexperiments run on the KDD Cup 1999 data set shows theimprovement in detection rate and decrease in false positiverate and the ability to detect unknown intrusions. © 2011 IEEE.


Jin Y.,China Nuclear Power Technology Research Institute
Hedongli Gongcheng/Nuclear Power Engineering | Year: 2016

PWR fuel assembly holddown spring systems generally consists of three to five spring leafs. To analyze the stiffness of the holddown spring system, commercial FEM code is usually used for the evaluation currently. But the optimization capability of the main current commercial FEM code is weak, during the research and development progress, it usually cannot screen a better performance design product. This paper established the holddown spring stiffness analysis model from the perspective of theoretical analysis. Using the established theoretical analysis model, the paper gives three main factors impacting the holddown spring stiffness: leaf thickness, leaf width and leaf height, and also give the analysis on how these factors affecting the holddown spring stiffness. © 2016, Editorial Board of Journal of Nuclear Power Engineering. All right reserved.


Li R.,China Nuclear Power Technology Research Institute
Gongneng Cailiao/Journal of Functional Materials | Year: 2012

Low-temperature sintering experiments of UO 2+x pellets and the results were reported in this paper. 12 groups pellets were sintered in vertical molybdenum wire furnace with N 2+CO 2 partially-oxidative atmosphere. Densities which achieved 10.41g/cm 3 (94.98% theoretical density) could be sintered at a much lower temperature (more than 400K) while UO 2 pellets were sintered at 2073-2273K in hydrogen. A defect model of hyper-stoichiometry uranium dioxide was built for studying the active mechanism. The diffusion coefficient was positive to partial pressure of oxygen (P O2) or excess oxygen ions (x in UO 2+x). The sintered densities of UO 2+x pellets were predicted by diffusion coefficient of uranium ions at 1073, 1273, 1473 and 1673K. The theoretical sintering temperature of UO 2+x in partially-oxidative atmosphere was also calculated when x was 0.04. The results of sintered densities and sintering temperature were agreed to experimental results very well.


Patent
China Nuclear Power Technology Research Institute and China Grneral Nuclear Power Co. | Date: 2013-12-20

A bottom nozzle includes a skirt, support blocks, transverse blades and longitudinal blades. The skirt is a hollow structure and a bottom thereof is provided with corner legs which are protruded downwards, a cavity is defined in the hollow structure, the transverse blades are configured in the cavity, the longitudinal blades are configured in the cavity, the transverse blades and longitudinal blades are firmly connected with the skirt, projections of the transverse blades and the longitudinal blades in a level plane are intersectant to form interleaved grids, and the support blocks run through and are fixed on the transverse blades and the longitudinal blades. In such a way, the bottom nozzle forms a three-dimensional gridded water passage, thereby improving the filter capacity and generating small water pressure drop.


Patent
China Nuclear Power Technology Research Institute | Date: 2014-11-21

A nuclear core component hold-down assembly includes a hollow spring guide in which an instrumentation insertion channel is formed; a base plate which has a center hole formed through a center thereof, and several water flow holes formed around the center hole; a lower end of the spring guide connecting and mating with an upper end of the base plate, the instrumentation insertion channel communicating with the center hole, and the base plate locating above the adapter plate and pressing against it directly; a hold-down bar slidably mounted on an upper end of the spring guide and locating above the base plate; and a spring element configured between the hold-down bar and the base plate, by which the hold-down bar pushes the base plate to cause the base plate to press against the adapter plate. The structure is stable and reliable.

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