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Bi D.,Tsinghua University | Feng C.,China Nuclear Power Technology Research Institute | Ge B.,Beijing Jiaotong University
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2012

Saturation of current transformer may cause mal-operation of differential protection during the period of fault removal, sympathetic inrush or recovery inrush. The paper analyzed the character of relative accumulation of flux linkage of current transformer, and proposed an algorithm to diagnose phase-shift saturation of current transformer while the current transformer transferred a small power frequency current under the condition that large remanent flux and DC flux linkage accumulation was produced in current transformer. Assuming that one current transformer used for differential protection did not saturate and the other one saturated, the paper proposed an algorithm to diagnose phase-shift saturation of current transformer according to the characteristic of flux linkage accumulation. The variance of relative flux linkage accumulation and the number of inflexion point in the enabled zone was calculated. The dynamic experiments and field data verified that the algorithm had good performance in detecting phase-shift saturation of current transformer. © 2012 Chinese Society for Electrical Engineering. Source


Fang Y.,China Nuclear Power Technology Research Institute
Applied Mechanics and Materials | Year: 2014

As one of the key equipment for handling nuclear assembly in nuclear power station, the Nuclear Fuel Elevator (NFE) is mainly used to handle the new assembly and examine the spent assembly. Considering the safety and reliability for the high radioactivity environment, the control system with two levels of hardware controllers and module hierarchical software architecture is proposed. The HMI which is convenient and user-friendly is also developed for operator. The load protection and dynamic PID-control is mentioned in detail. © 2014 Trans Tech Publications, Switzerland. Source


Li R.,China Nuclear Power Technology Research Institute
Hedongli Gongcheng/Nuclear Power Engineering | Year: 2014

In this paper, the low temperature sintering technology to UO2pellets has been introduced, and we have studied the high temperature creep properties of the pellets which manufactured by low temperature sintering. The sintering temperatures are 1073 K, 1273 K, 1473 K and 1673 K, sintering time are 1 hour, 2 hours and 3 hours respectively. We obtained the highest sintering density of pellets at 1673K with 3 hours, which is 10.41 g/cm3 (94.98% theoretical density). The grain size of pellets which prepared by low temperature sintering technology and traditional technology are 9.0 μm and 23.8 μm respectively. So the high temperature creep properties of the two kinds of pellet must be studied. They were performed at 20-50 MPa, 1673 K and 1773 K respectively, under a nitrogen atmosphere to shorten the experimental time. According to the results, the creep rates of sintered UO2 with the grain sizes of 9.0 μm and 23.8 μm under the load of 10MPa are almost the same. The creep process is controlled by both Nabarro-Herring creep and Hamper-Dorn creep for uranium dioxide with grain size of 9.0 μm; while Hamper-Dorn creep is the dominant mechanism for uranium dioxide with grain size of 23.8 μm. Source


Zhang S.,China Nuclear Power Technology Research Institute
Hedongli Gongcheng/Nuclear Power Engineering | Year: 2014

This paper introduce the thermal hydraulic characteristic of the liquid in the high pressure safety injection dead lines, and analyze the mechanism and harm of thermal fatigue which may occur on these pipes. A modification is proposed for Daya Bay and Ling'ao Phase I nuclear power plants high pressure saft injection deadline, and take fatigue analysis on pipes added by the modification, find that there is no pipes added by the modification become fatigue after various produce condition loaded on it, demonstrate the efficiency and safety of the well modification. Source


Qi L.C.,China Nuclear Power Technology Research Institute
Advanced Materials Research | Year: 2014

The performance of a controller is usually characterized by several attribute indexes. In this context, this paper applies multi-attribute decision-making techniques to the assessment of control performance, which takes into account both stochastic and deterministic performance indexes. Case studies demonstrate the validity of the proposed method. © (2014) Trans Tech Publications, Switzerland. Source

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