[en] In this concept of long-life core (they are sometimes called B-B (Breed and Burn)), tall blanket is placed above the relatively short driver fuel. In the initial stage of burning, the power by fission is mostly generated in the driver region and it moves into the blanket region. The power and flux distributions that are highly peaked in the axial direction propagates slowly from the driver into the blanket region. This concept of long-life core fully utilizes the breeding of blanket in the fast spectra and it can achieve very high burnup of fuel. In this work, we introduce new sodium cooled longlife cores rating 600MWe (1800MWt). In these cores, the driver regions are heterogeneously placed into blanket region so as to achieve stabilized and less peaked axial power distribution as depletion proceeds. At present, our study is focused on only two axial driver regions but this concept can be easily extended onto the multi-driver region concept. The cores designed in this paper have two axial driver regions so as to have stabilized and less peaked axial power distributions as depletion proceeds. The results of the core design and analyses show that the cores have very long-lives longer than -49EFPYs and high discharge burnup higher than 200GWD/kg. Additionally, we considered a long-life core having no blanket. As expected, it was shown that these cores have stabilized and less peaked axial power distribution as the fuel depletes. However, the study shows that the cores having two driver regions still show high initial peaking of the axial power distributions and the core can be optimized by changing the driver fuel height

[en] To test the performance of magnetic levitation control rod driving line and verify the stability and reliability, the comprehensive study on drive line is conducted. The operational performance test gives out the static and dynamic parameters of the driving system and driving line. The operational life test proves the stability and reliability of the control rod driving line and verifies the comprehensive performance. (authors)

[en] Some of the issues that are important in assessing fusion-- fission energy systems from a utility perspective are discussed. A number of qualitative systems-oriented observations are given along with some economic quantification of the benefits from fusion--fission hybrids and their allowed capital cost. (U.S.)

[en] We present in this paper some results obtained with a numerical model of control rod behaviour. Drop time and insertion force are studied by means of a large parametric analysis. Fuel assembly deflection is the main parameter of this study. Several loads are taken into account in control rod displacement calculation: fluid load, gravity and friction force against the guide. Simulations are compared to measurements carried out in a full-scale prototype. The analysis of drop calculation shows that the friction cannot be neglected when fuel assembly is bowed. The main result for insertion force calculation is the important sensitivity to data entry. Determining exact deflection all along assembly with precision is needed. Otherwise, approximated friction force is obtained. (author)

[en] This paper discusses the behavior of the hydraulic control rod driving system (HCRDS) in cyclical swing. The first generation HCRDS with the hole-hole step cylinder, the important driving component, has been applied in 5 MW nuclear heating reactor for several years and run well all along. The second generation with the chamfer-hole step cylinder has also been developed and studied. The HCRDS working principle, as well as the particular design of the hole-hole step cylinder, has been introduced in the paper. The control rod (CR) behavior when HCDRS vacillating in certain swing and cycle has been analyzed subsequently. The calculating result indicates that the CR can keep its balance in such unstable state and the operation of driving CR upwards or downwards can function properly likewise. In cyclical swing, the CR can drop down quickly and meet the reactor shut-down needs. The theoretical analysis proves the HCRDS reliable and safe, establishing basement for its further research and wide use

[en] The High-Speed Digital Camera experimental technique for obtaining the displacement, velocity, acceleration and the most biggest rebound height of the Control Rod Drive Line (or CRDL) in the CRDL characteristic experiment are introduced, and the prospect of this application is advised too. (authors)

[en] A set of hyperbolic equations is given to describe the vibration of the nuclear reactor core. The vibration propagates in the core in the form of the traveling wave. According to the minimum of the traveling wave energy, an active control law is given. (author)

No abstract available

No abstract available

[en] A guide tube for a fuel element assembly gripper unit is radially displaceable on a parallel linkage from the lower end of a vertically disposed rotatable support structure. The gripper unit is longitudinally slidable within the guide tube to enable a fuel element assembly to be fully withdrawn into the guide tube. The gripper unit has a rotatable gripper head for rotating the fuel element assembly about its longitudinal axis. (U.S.)