核动力工程

Standard Problem of Nuclear Power Localization in China

ZHANG Jing-cai, ZHOU Yue-min

2004, 25(4): 289-292,296.

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French nuclear power standard system includes the French nuclear laws, principal safety guides, RCC serial standard and technical documents. The RCC serial standard reachs on the design and construction of nuclear power plants, and is principally a closed standard system. The RCC serial standard have been used the design and construction of Qinshan phase-Ⅱ, the RCC-M have been used the mechanical components of nuclear island. It is suggested that the Chinese nuclear power governing body research the problems relating nuclear power standard during the localization in China, the present condition of the Chinese nuclear power standards, and begin to develop the Chinese nuclear power standard based on the ASME B & PVC, RCC serial standard and Chinese practical experienced in nuclear power engineering. Chinese nuclear power standard should be the strict, well applicable and advanced in the world, and should be continuously updated according to the accumulated operating experiences, technological progress and changes in regulatory requirement.

HTR-10 On-Line Monitor System for the Implimentation of Technical Specification

WANG Yong-hui, HU Shou-yin

2004, 25(4): 293-296.

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The on-line monitor system for the implementation of technical specification for 10WM High Temperature Reactor （HTR-10） is based on data supplied by HTR-10 instruments and control system, which intelligently simulate the behavior of operators, analyze and judge in real time whether the state of reactor system and instruments is accordant with the technical specification standard, and at the same time auto-matically conduct some periodical tests and checks in specified frequencies and reminds the operators of the checks that can not be conducted in time. It can avoid the negligence by manual check of the implimentation of the technical specification. This paper introduces system model, composition modules, technical devel-opment characteristics and method in the practical application.

Axial Power Difference Control Strategy and Computer Simulation for GNPS during Stretch-out and Power Decrease

LIAO Ye-hong, XIAO Min, LI Xian-feng, ZHU Min-hong

2004, 25(4): 297-300.

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Successful control of the axial power difference for PWR is crucial to nuclear safety. After analyzing various elements’ effect on the axial power distribution, different axial power deviation control strategies have been proposed to comply with different power decrease scenarios. Application of the strategy to computer simulation shows that our prediction of axial power deviation evolution is comparable to the measurement value, and that our control strategy is effective.

Measurement and Evaluation of Temperature Coefficient of 10 MW High Temperature Gas-Cooled Reactor-Test Module

HU Shou-yin, WANG Rui-pian, JING Ying-qing, LIANG Xi-hua

2004, 25(4): 301-304.

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T Without any auxiliary heating source, the core is heated by means of main helium circulator and nuclear power no more than 500kW and temperature coefficient of HTR-10 has been measured. Reactivity change caused by temperature rise from 45.48℃ to 236.93℃ is obtained with cycle method. Measured results are evaluated by physical calculation, and calculated values agree well with the measured values when there no effect of xenon poison and temperature distribution.

Study of Critical Heat Flux in Rectangular Channel with Narrow Gap under Natural Circulation Condition

LU Dong-hua, HUANG Yan-ping, BAI Xue-song, XU Xian-qi

2004, 25(4): 305-308.

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Critical heat flux （CHF） in rectangular channel with narrow gap is investigated and compared to the prediction of Sudo equations under low pressure and low mass velocity. Though the majority of experimental data are less than prediction, they are still in the zone of 33% deviation permitted by Sudo equations. It proves Sudo equations can predict CHF in this type of rectangular channel.

Instability Analysis of Once-Through Boiling Flow System

HE Jian-ping, ZHAO Fu-yu, XIAO Ze-jun, HUANG Yan-ping

2004, 25(4): 309-313.

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Considering the characteristic of once-through boiling flow system, the simplified dynamic model with lumped parameter moving boundary is used to describe two-phase flow feedback system in this paper for instability analysis. The transfer-functions for instability analysis are derived from the frequency-domain analysis method on automatic control. The Matlab software and its simulink tools are used to analyze and simulate the instability of once-through boiling flow system. Then the stability boundary curves under the effect of some major factors are obtained in this paper.

Study of Effect Parameter on the Oscillation in Parallel Multi-channels

HUANG Yan-ping, MA Jie-liang, XIAO Ze-jun, ZHANG Xing-wu, LIU Shao-bo

2004, 25(4): 314-318,336.

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An experiment has been performed in National Key Laboratory of Bubble Physics and Natural Circulation（BPNC）,Nuclear Power Institute of China（NPIC） to study the effect of the main operating parameters and the inlet restriction pressure-drop on the oscillation among channels. The experimental results show that the increasing of the temperature of feed water increases the oscillation amplitude , but it is not of linear relationship; the increasing of steam pressure decreases the oscillation amplitude, but there is no effect on the oscillation period; the increasing of feed water flow rate decreases the oscillation amplitude and increases the oscillation frequency; the increasing of the input power improves the stability of secondary side of test section; and the increasing of the restriction pressure-drop improves the stability of test section.

Experiment Study of the Onset of Nucleate Boiling in Narrow Annular Channel

WANG Jia-qiang, JIA Dou-nan, GUO Yun, YAN Ming-yu, QIU Sui-zheng, SU Guang-hui, LU Dong-hua

2004, 25(4): 319-323.

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The onset of nucleate boiling （ONB） was investigated for water flowing in the annular duct which clearance is 1.2mm at the pressure range from 1.0 to 4.5MPa.The effect on ONB of some thermodynamics parameters was also analyzed. The available data dealing with sub-cooled boiling initial point of water in narrow annular clearance duct are analyzed by using regression method. The new developed correlation was obtained by considering the bilateral heating factor.

Probabilistic Safety Assessment of Station Blackout Accident and 5th Emergency Diesel in Daya Bay NPP

WANG Chao-gui, GUO Jian-bing

2004, 25(4): 324-327.

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In this paper, probabilistic safety assessment （PSA） of the station blackout （SBO） and 5th emergency diesel in Daya Bay NPP has been carried out, the calculation method of non-recover factors of power supplies is given, and sensitivity analysis on the connection duration of 5th emergency diesel has been executed. It is concluded that the core damage frequency （CDF） induced by SBO is relatively large, the addition of 5th emergency diesel is very helpful for the CDF reduction, and the connection duration of this diesel has great effect on the CDF reduction.

Research on Fault Diagnostic System of Nuclear Power Plant Based on Fuzzy Neural Network

LIU Yong-kuo, XIA Hong, XIE Chun-li, YAN Chang-qi

2004, 25(4): 328-331.

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The fuzzy logic and neural network are combined in this paper, and the distinct differences and connections between the fuzzy logic and neural network are compared. Furthermore, the algorithm and structure of the fuzzy neural network are introduced. This theory is applied to the nuclear power plant, and the fault diagnostic system of the nuclear power plant based on fuzzy neural network is built. In order to test the validity of the system, the inverted U-tubes break accident of steam generator is used as an example and many experiments are done. The test result showed that the fuzzy neural network could identify the fault.

Design and Performance Test of the Helium Safety Valves for HTR-10

WU Xin-xin, DONG Jian-ling

2004, 25(4): 332-336.

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Two sets of helium safety valves are installed in the safety discharge system in the primary loop of 10MW High Temperature Helium Cooled Test Reactor (HTR-10, which are nuclear safety class 1 components and one of the key devices to guarantee the safety of HTR-10. The present paper gives the design requirements and structural features as well as performance requirements of the helium safety valves. The demonstration test for performance of the helium safety valves were carried out in special test system according to the requirement of ASME Section III code. The test result showed that the performance of the helium safety valves can meet the design requirement and relevant nuclear codes.

Verification of the Design of Sub-critical Device for Accelerator Driven System

YU Tao, SHI Yong-qian, XIA Pu, LIAO Yi-xiang

2004, 25(4): 337-339.

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Considering the need of Accelerator Driven System （ADS） research and the experiment condition, critical calculation of the sub-critical device arrangement of ADS is carried out with 3-D M-C （MCNP） and the k_eff is ensured between 0.92~1.0. The original data is provided for the design of ADS sub-critical experiment equipment.

Numerical Simulation and Analysis for the Baking out System of the HT-7U Super-conducting Tokamak Device

SONG Yun-tao

2004, 25(4): 340-345.

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It can provide an ultrahigh vacuum location for the plasma operation. In order to improve its vacuum degree and attain a high quality operation environment for plasma, it is very important to proceed 250℃ baking out to clear the wall before the plasma operation. The paper firstly gives two kinds of structures for the baking of the vacuum vessel, in which one is the baking by electricity and another is baking by the nitrogen gas. Secondly based on the numerical simulation and analysis, some results have been attained such as the baking power, temperature field distribution and thermal stress for the vacuum vessel, which can provide some valuable theory basis for the engineering design and optimization of the baking system of the HT-7U vacuum vessel or other similar super-conducting tokamak devices.

Study of the Application of A New Fuel Assembly CANFLEX in QinShan Phase Ⅲ Heavy Water Reactor

LI You-yi, XIE Zhong-sheng, HUO Xiao-dong, YU Hui, SHI Xiu-an

2004, 25(4): 346-351.

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In this paper the new fuel assembly CANFLEX for CANDU reactor is introduced. The physical performances and thermal-hydraulic characteristics of assembly and the feasibility of its application in CANDU-6 reactor of QinShan PhaseⅢ are studied. Calculations demonstrate that the margin of reactor safety has been increased by the improvement of thermal-hydraulic characteristics. Replacing the NU-37 assembly by CANFLEX in CANDU-6 reactor will not have influence on the in-core power distribution and peaking power and the power fluctuation as well. It is proved that the application of new CANFLEX assembly in CANDU reactor of QinShan Phase Ⅲ is safe and feasible with significant economy benefit.

Study on the Plasticity Accumulation Behavior of T225NG Alloy Under Cyclic Stress Loading

CAI Li-xun, NIU Qing-yong, LIU Yu-jie, QIU Shao-yu, LI Cong

2004, 25(4): 352-356,365.

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A series of uniaxial ratcheting tests of T225NG alloy at room temperature were performed and the plastic strain accumulation behavior of the alloy was investigated. Based on the test results for T225NG alloy, one available equation to describe constitutive relationship between plastic strain accumulation and peak stress in ratcheting shakedown and another exponential model to describe the evolution law of ratcheting strain were presented in this paper. Finally, effects of creep on the plastic strain accumulation were investigated, and the result showed that, the smaller the stress amplitude was, the larger the creep part in plastic strain accumulation was.

Synthesis of Thermoelectric Material β-Phase FeSi₂ by Field Activated Method

LIU Xiao-zhen, ZOU Cong-pei, Z. A. Munir

2004, 25(4): 357-360.

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β-phase FeSi₂ was synthesized by Field Activated Method from Fe and Si powder mixture with small addition of Cu. The synthesis, solidification and heat treatment are completed in one step by this method. This paper investigated the effect of small addition Cu on synthesis rate and microstructure. The results show that copper can dramatically increase the phase transformation rate. Holding time do not influence the amount of remainedεphase, but finger shape of Si rich regions changes with the increase of holding time.

Corrosion Behavior of Zirconium-Ion Bombardment on the Zircaloy-4 and Investigation with Slow Positron Annihilation Spectroscopy

PENG De-quan, BAI Xin-de, CHEN Xiao-wen, ZHOU Qing-gang, LIU Xiao-yang, DENG Ping-ye

2004, 25(4): 361-365.

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In order to investigate the affect of Zr-ion bombardment on the corrosion resistance of zir-caloy-4, specimens were bombarded by zirconium ions with a fluence range from 1×10¹⁵ to 2×10¹⁷ ions/cm², using a MEVVA source at an extract voltage of 50 kV. The valence of the surface layer was analyzed by X-ray photoemission spectroscopy （XPS）; the thickness of the oxide film was measured by auger electron spectroscopy （AES）. Three-sweep potentiodynamic polarization measurement was used to value the corrosion resistance of bombarded zirconium in a 1N H₂SO₄ solution. Slow positron annihilation spectroscopy （PAS） measurement was employed to obtain to the distribution of the implantation induced defects. A significant improvement of corrosion resistance was achieved compared with as-received zircaloy-4 except for 1×1015 Ions/cm² fluence, and the sample with 5×10¹⁶ ions/cm² fluence is most anti-corrosive in all the samples. The natural corrosion potentials of bombarded samples decline with raising the bombarded fluences. It was found that there was some relationship between the corrosion behavior of Zr-ion bombarded zircaloy-4 and the slow positron annihilation spectroscopy （PAS）.

Experimental Study on Uniaxial Cyclic Ratcheting Behavior of 304 Stainless Steel at Room Temperature

YANG Xian-jie, GAO Qing, CAI Li-xun, LIU Yu-jie

2004, 25(4): 366-372.

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The cyclic tests for 304 stainless steel with solution heat treatment under uni-axial cyclic straining and stressing were carried out systematically. The effects of the cyclic engineering stress amplitude history with constant mean stress, the mean engineering stress history with constant cyclic stress amplitude and the stress amplitude histories with the specific mean stress increment per cycle on the uni-axial ratcheting deformation behavior were investigated. Some significant results are obtained.

Analysis of the Discrepancies of Reactor Coolant Flowrate Measurement in Unit 2 of Ling’ao Nuclear Power Plant

ZHAO De-yuan, ZHOU Huo-tang

2004, 25(4): 373-376.

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Based on the reactor coolant flow rate measurement principles and various data measured, analysis is performed on the abnormal phenomena in the reactor coolant flow rate measurement of Loop No.2, during the commissioning of unit 2 of Ling'ao Nuclear Power Plant. Together with site tests and test verification, it has been found that the root cause is the minor manufacturing deviation of the flow rate sensor. The temporary solution has been made to displace the flow rate transmitter range and adjust the parameters of the flow rate measurement circuit. Meanwhile the permanent solution to replace the flow rate transmitters during the first refueling outage is being proposed.

Operator Psychological Selection System for Nuclear Power Plant

HE Xu-hong, GAO Jia, HUANG Xiang-rui

2004, 25(4): 377-380.

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Based on a detailed job analysis of nuclear power plant operator including operation procedures analysis, interview with personnel familiar with operator job, and 9 events happened in the past in the plant involved operator error analysis, several operator work characteristics and performance influence factors are obtained. According to these specific characteristics and factors, referring to the psychological selection research results in the other related critical occupational fields, a full psychological selection system of nu-clear power plant operator is forwarded in this paper, including 21 dimensions in 3 facets as general psycho-logical ability, personality and psychological healthy. Practical measurement methods for the proposed selection dimensions are discussed in the end.

Research on Radioactive Distribution in Rare-Earth Materials

SHUAI Zhen-qing, ZHU Shi-fu, ZHAO Bei-jun

2004, 25(4): 381-384.

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The radioactive contents in some Rare earth materials which have been produced with RE ores in Sichuan Panxi area has been analyzed by the INAA technique and the Gamma-ray spectrum technique. The research on radioactive distribution and character of physics as well as chemistry in acid processing procedure has been completed. The results obtained show that the natural radioactive material in Rare- Earth ores in Sichuan Panxi area are mainly thorium series, meanwhile radioactive contents of uranium series are about 12 times lower than the contents of thorium series,total α radioactive contents in RE ores （60%） are 8.2×10⁴~9.2×10⁴Bq.kg^-1;total α radioactive contents in RECl₃（abundant La） are 8.8×10² ~4.18×10³Bq kg^-1;totalαin the RE alloys are 5.1×10²~2.6×10⁴ Bq kg^-1;and totalαin the pure RE compounds are lower than 1×10²10³Bq kg^-1.

2004 Vol. 25, No. 4