核动力工程

Study of the Utilization of Slightly Enriched Uranium in Qinshan Phase Ⅲ Candu Reactor

HUO Xiao-dong, XIE Zhong-sheng

2004, 25(2): 97-100.

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The feasibility of application of slightly enriched uranium （SEU） in CANDU reactor of Qinshan Phase III NPP under the time-averaged equilibrium refueling was studied in this paper using the code system DRAGON/DONJON. The optimum enrichment of Qinshan CANDU reactor was determined to be 1.125wt%. The instantaneous SEU reactor core was calculated and inspected based on the patterned channel age model. It is shown that the simple 2 burnup zones, 2/ and 4-bundle-shift refueling scheme will satisfy the license limits of the maximum bundle power and channel power, which are 935KW and 7300KW respectively. It was estimated that using this optimum enrichment SEU in Qinshan Phase III will increase the burnup to 18.5GWd/tU, save 53 tons of natural uranium resource, decrease the spent fuel to be disposed to 116 ton and obtain 8.15M$ benefit annually. The transition from the nature uranium （NU） to the slightly enriched uranium （SEU） can be completed without major modification of the structure of reactor core and operation mode. This strategy has significant practical and economical benefit.

Some Problems of Neutron Source Multiplication Methodfor Site Measurement Technology in Nuclear Critical Safety

SHI Yong-qian, ZHU Qing-fu, HU Ding-sheng, HE Tao, YAO Shi-gui, LIN Sheng-huo

2004, 25(2): 101-105.

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The paper gives experiment theory and experiment method of neutron source multiplication method for site measurement technology in the nuclear critical safety. The measured parameter by source multiplication method actually is a sub-critical with source neutron effective multiplication factor k_s,but not the neutron effective multiplication factor k_eff. The experiment research has been done on the uranium solution nuclear critical safety experiment assembly. The k_s of different sub-criticality is measured by neutron source multiplication experiment method, and k_eff of different sub-criticality, the reactivity coefficient of unit solution level, is first measured by period method, and then multiplied by difference of critical solution level and sub-critical solution level and obtained the reactivity of sub-critical solution level. The k_eff finally can be extracted from reactivity formula. The effect on the nuclear critical safety and different between k_eff and k_s are discussed.

Application of Monte Carlo Method in Shielding Calculation of ADS

LIAO Yixiang

2004, 25(2): 106-108,132.

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The distribution of neutron flux inside the proton beam duct and escaping from its entrance or other outside surfaces of ADS （Accelerator Driven System）, which is the nuclear system of new generation, was calculated with Monte Carlo method. Some useful conclusion for the design of ADS had been obtained.

Experimental Research on Temperature Difference between two Phase Flow in Steam Injector

LIU Ji-ping, YAN Jun-jie, XING Qi-nan, CHEN Guo-hui, LIN Wan-chao

2004, 25(2): 109-112.

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An primary experimental research on the temperature difference between the phases has been performed in the super-sonic steam and liquid two phase flow in the steam inject. As the thermal resistance in the direct contact heat transfer between steam and cool water, there exists obviously the value of temperature difference. It increases with the flow ratio of water to steam, but keeps constant while the flow ratio is greater than a specific value. It reaches its minimum value at a critical mass flow rate. The results are both theoretically and practically valuable.

Research on the Pressure-lifting Performance Calculation Model of Supersonic Steam-Water Two-Phase Flow in Channel of Variable Section

HE Yang-peng, YAN Jun-jie, LIU Ji-ping, ZHAO Fu-yu, LIN Wan-chao

2004, 25(2): 113-117.

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According to the experiment results of steam-water two-phase flow in variable channel （Steam Injector）, the relationships among the outlet pressure of water nozzle and the inlet low-pressure water temperature, flow flux,or the water temperature rise are quantitatively studied. The mathematical formula for the outlet pressure of water nozzle is obtained. Then the pressure-lifting performance calculation model of supersonic steam-water two-phase flow in variable channel is developed. The error between the calculation result using this model and the experiment result is less than 10%. These are beneficial to the development of the lifting pressure technology with supersonic two-phase flow in channel of variable section.

Experimental Investigation on the CHF of Rectangular Channel with Narrow Gap under High Mass Velocity

LU Dong-hua, HUANG Yan-ping, BAI Xue-song

2004, 25(2): 118-122.

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An experiment, focused on the down flow CHF in rectangular channel with narrow gap, was performed under high mass velocity and low outlet pressure. The results show that CHF almost linearly goes up while mass velocity is increased, and while the exit quality rises, CHF falls down. The prediction of Sudo correlation underestimates experimental data. When inlet parameter is the same, the length of rectangular has little effect on CHF; but when the exit parameter is considered, the longer the channel is, the lower CHF is.

Experimental Investigation of Single-phase Flow Friction in Narrow Annuli

SUN Zhong-ning, SUN Li-cheng, YAN Chang-qi, HUANG Wei-tang

2004, 25(2): 123-127.

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Experimental investigations of water flow friction in horizontal narrow annuli, with gap sizes of 0.57-3.08 mm, were carried out. The tests involved both laminar and turbulent flow regimes. The critical Reynolds number transited from laminar flow to turbulent flow was examed and observed. The friction factors obtained from experiments were compared with conventional correlations evaluated results, and the influences of channel scale and eccentricity on flow friction characteristics were discussed. It was found that fluid friction in turbulent regime could be predicted by conventional correlations with satisfied degree, but both values and varying trend of that vs. r_i/r_o in laminar regime were obviously departure from theoretically results when the gap sizes were less than 2.0 mm, and the critical Reynolds number was slightly less then 2300 when the gap sizes were less than 1.0 mm.

Study on the Property of Iodine-induced Stress Corrosion Crack of New Zirconium Alloy

CUI Xu-mei, PENG Qian, LI Jing-yuan, TANG Zheng-hua, LI Yan-rong

2004, 25(2): 128-132.

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The investigation was conducted on two plates of recrystallized new N18 zirconium alloy i.e N18-1（T-L） and N18-2（L-T）, which are with the same chemistry composition but different texture. In order to study the property of iodine-induced stress corrosion crack of the zirconium alloy plates, the tests were carried out in different test conditions, and dynamic monitor was used to measure the length of stress corrosion crack. The texture, the second phase particles and fractographs were also investigated. Result shows that N18-2 （L-T） has better I-SCC resistance than N18-1（T-L） at the two set of test conditions. In addition, SEM observation shows that the cracks are mainly trans-granular and pseudo-cleavage, but at the first stage, the crack is inter-granular.

Fatigue Characteristics of New Zirconium-Based Alloys Under Low Cycle Loading

GOU Yuan, LI Yan-rong, CHEN Hong-tong, LI Wei-jun, WANG Yun-hui

2004, 25(2): 133-136.

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Fatigue crack of materials induces very large calamity because of its abruptness. According to literature researches, fatigue destroy hold 80~90% in all of mechanical invalidation. In this paper, we adopt three kinds of φ 9.50.57mm thin-wall tube samples, and finish low cycle fatigue test at 5 kinds of strain levels. We get the relationships of Δε_t-N and fatigue imitation function. Furthermore, the fatigue crack microstructure is analyzed and the mechanism of fatigue is discussed.

Effect of Texture on Cyclic-deformation Behavior of Zircaloy-4

LI Cong, TAN Jun, YING Shi-hao, SHEN Bao-luo, QIU Shao-yu

2004, 25(2): 137-141,167.

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In this paper, effect of texture on cyclic-deformation behavior of Zircaloy-4 has been investi gated. The results indicate that (1) the alloy obeys the Coffin-Manson relation ( $N_{\mathrm{f}}^\beta \Delta \varepsilon_p=C$ ), the low-cycle fatigue life in the rolling direction is higher than that in the transverse direction at a given $\Delta \varepsilon_p$, and the life difference between both directions becomes larger with lowering the $\Delta \varepsilon_{\mathrm{p}}$; (2)the alloy shows cyclicdeformation softening till fracture under low strain amplitude, showing cyclic-deformation hardening in the early stage and then cyclic-deformation softening till fracture under high strain amplitude, and the grains would rotate with the cyclic-deformation going on at a given amplitude where these grains have higher Schmid factor; (3) $\sigma_{\mathrm{s}}$ at half-life obeys the power law relation $\sigma_{\mathrm{s}}=K^s \varepsilon_p^{n^s}$, and $\sigma_{\mathrm{ib}}$ obeys the logarithmic relation $\sigma_{\mathrm{ib}}=K^b \ln \varepsilon_p+C_{\mathrm{b}}$; (4) the cyclic-deformation behavior difference in both directions stems from the texture effect. Finally, the mechanism on texture effect has been discussed in detail.

Random Cyclic Strain-Life Relations of 0Cr18Ni10Ti Pipe Steel

ZHAO Yong-xiang, YANG Bing, LI Peng-zhou

2004, 25(2): 142-146.

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Experimental study is performed on the random cyclic strain-life relations of the new pipe steel, 0Cr18Ni10Ti, by strain-controlled fatigue tests. Probabilistic models for characterizing the relations are presented on a basis of the Coffin-Manson strain-life equation. Three kinds of effects on probabilistic assessments are taken into account, which are the scattering regularity, the amount, and the combined effect of scattering regularity and the amount of the test data. With respect to these effects, the models are consisted of three kinds of probabilistic curves, i.e. the survival probability-strain-life curves, the confidence-based strain-life curves, and the probability and confidence-based strain-life curves. Availability and feasibility of the models are indicated by an analysis to the test results.

Effect of Heat Treatment on the Microstructure and Corrosion Resistance of Zirconium Alloys with Nb Welding Samples

YAO Mei-yi, LI Qiang, ZHOU Bang-xin, MIAO Zhi, YU Ying-hua, LIU Wen-qing

2004, 25(2): 147-151.

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The butt joints of Zr-1.88Sn-0.35Fe-0.52Nb and Zircaloy-4 plates were made by electron beam welding. The corrosion tests of welding samples were carried out in autoclave at 400C, 10.3MPa superheated steam for 165 days. The thickness of oxide films of these corrosion samples in different zones on welding surface and the opposite side of welding surface was measured by means of optical microscopy. The microstructures of different zones were also examined by transmission electron microscopy （TEM）. The results show that the corrosion resistance of welding samples is obviously improved by annealing at 500C, and the thickness of oxide films is 10-20 times different between the annealed sample and non-annealed sample on the same molten and heat-affected zones. This is mainly due to the decomposition of βZr, which was formed because of the containing of Nb and the cooling from b phase after welding, into αZr+βNb after annealing at 500C. The corrosion resistance of molten zones is excellent after annealing at 500C-1.5h, on which the thickness of oxide films is thinner than 2μm after corrosion for 165 days. It is only 30mg/dm² if converted into the weight gain. The composition of molten zones is about Zr-1.2Sn-0.25Nb-0.25Fe-0.02Cr according to the analysis of electron microprobe.

Calculation of Calibration Coefficient of Out-core RPN System

ZHU Sheng-dong, DENG Li, LI Shu, XIONG Chun-hua, YAO Zeng-hua, ZHANG Hong, LI Dong-sheng

2004, 25(2): 152-155.

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The response Matrix of assembly （or Node） to out-core chamber of a nuclear power plant is calculated by Monte Carlo Method （M.C.） and code. By means of which, the currents of each section of the chamber and the calibration coefficient are calculated. Therefore the theory in-core thermal power level P_r and axial offset ΔI are obtained. The theory results of different cycles and different Xe oscillation steps are compared the measured data. It shows that the numerical method is suitable for modeling out-core RPN system. The accuracy of calculation is sufficient for engineering precision.

Application of Plant Data Acquisition and Intelligent Data Processing System in Ling’ao Nuclear Power Station

HE Yu, ZHANG Bing

2004, 25(2): 156-159.

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In this paper, the function and usage of the application program interface of the KIT plant data acquisition system used in Unit 1 ＆ 2 of LingAo Nuclear Power Station is analyzed and studied. A Web-based on-line process data display and monitor system has been developed by our own methods. Functions of collecting and publishing process data on a real-time basis, remote monitoring of production process, and fault diagnosing of instruments and sensors are implemented. In addition, application of a neural network based intelligent data processing system in predicating generated electrical power in nuclear power station is discussed.

Review on Applications of Fuzzy Logic Control in Nuclear Power Systems and Issue Discussions

JU Xiaolong, CUI Zhen-hua, WANG Yong, ZHANG Nai-yao

2004, 25(2): 160-163.

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The studies on applications of fuzzy logic control （FLC） in nuclear power systems have demonstrated that FLC is an effective and feasible advanced method for intelligent and full-automatic control of nuclear power systems. A complete review and summary of the achievements from FLC application research has been presented in this paper, and some key issues to be solved in the application research and practical use of FLC have been discussed.

Quantification of the Probability of Repeatable Human Error Event in Risk Assessment

HUANG Xiang-rui, SHEN Zu-pei, HE Xuhong, GAO Jia

2004, 25(2): 164-167.

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This paper described modeling and quantification of the probability of repeatable sequential human error event in application of risk assessment and induced some usual formula of calculation of human error event for task in serial or in parallel. It was proved by calculation of practical example that this model can solve more accurate calculation of the probability of the dependent repeatable sequential human error event and it can be used for calculation of unavailability including human error event in redundant systems.

Fuzzy and Hierarchy Decision Model for Nuclear Power Station Accident Emergency and its Application

ZHENG Dong-qin, ZHANG Chun-lin, XIAO Zhang, HU Guo-hui

2004, 25(2): 168-171.

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Considering the complexity in the decision-making at nuclear power station accident emergency, an optimization model for the nuclear accident emergency scheme is established with the application of hierarchic analyzing and fuzzy decision and the comprehensive analysis of multiple objectives for the decision-making. The model has been used in one real emergency decision-making, and the result shows that its reasonableness and operability has been improved.

Analysis and Calculation of the Power-unrecovery Factor in the Event Tree of Loss of Offsite Power

YI Yan, MEI Qi-zhi, SU Qing-shan

2004, 25(2): 172-174.

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Loss of offsite power is an initiating event that takes place often in the nuclear power plant. The effect of power recovery on the frequency of each sequence shall be taken into account in the event tree of loss of offsite power. In this paper, the method of calculating the unrecovery factors of different frontier systems is discussed.

State Commissioning of Evaporator Unit of Boron Recycling System of Ling-ao Nuclear Power Plant

LUO Ming-kun, LI Kai-feng

2004, 25(2): 175-179.

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This paper describes the function and states of the evaporator unit of boron recycling system of Ling-ao Nuclear Power Plant. Based on the state commissioning of the evaporator unit of boron recycling system, the items for states commission, the formula used in the commissioning of evaporator unit, and the state parameter curves of the evaporator from normal starting-up to sequential stopping states are presented. The origin and corrective measures for the problems occurred during the commission are also presented in the paper. The commission shows that the operation of the evaporator unit of boron recycling system can fully meet the design requirement.

Experimental Confirmation on the Natural Circulation Valve of Research Reactor

ZHANG You-jie, WU Xin-xin, JIANG Sheng-yao, XU Xian-qi, LI Sheng-qiang

2004, 25(2): 180-182,192.

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the natural circulation valve of Research reactor is one of the key facilities to remove the residual heat under the condition of natural circulation after the research reactor has been shut down. The special structure and remote operation rod with 10.5 m length has been adopted to meet the requirement onflow resistance and operation performance in the reactor. In order to obtain the practical resistance character of natural valve and confirmation reliability of natural valve, the experiment on seal performance, hydraulic performance and reliability of the valve have been carried out in simulation test loop. The experimental results show that the valve can meet all design requirement on research reactor facility.

Analysis of Measures for Public Radiation Protection at Nuclear Facility Emergency

AN Yong-feng

2004, 25(2): 183-186.

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The radiation protection measures that should be taken at different phases of nuclear facilityemergency were introduced in this report. The difficulties, which might be encountered in the implementation of radiation protection measures, the risk existing and the cost to be paid, were analyzed. Some methods for quick and rational selection of effective protection measures were provided, which could provide support to emergency intervention actions.

Conceptual Design and Feasibility Test of Two-Phase Hydrogen Thermal Siphon System of CNS in CARR

BI Qin-cheng, CHEN Ting-kuan, FENG Quan-ke, DU She-jiao, LI Xiao-ming, WEI Liang

2004, 25(2): 187-192.

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Conceptual design of the hydrogen system of cold neutron source （CNS） in China Advanced Research Reactor （CARR） was proposed, and feasibility test was carried out. In order to determine the void fraction in neutron moderator, the circulation ability of the two-phase hydrogen thermal siphon system, and the structure of components of the CNS, the mockup test was performed using Freon-113 as working fluid. To obtain the modeling criterion so that the above experimental results can be applied to the design of CARR, the bubble rising velocities in different liquids were investigated to study the effects of physical properties such as density, viscosity and surface tension on bubble rising velocity, void fraction and circulation ability.

2004 Vol. 25, No. 2