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The Development Of Fuel Rod Damage Character Analysis Code For Light Water Reactor Of Nuclear Power Plant

Posted on:2007-02-11Degree:DoctorType:Dissertation
Country:ChinaCandidate:P ChenFull Text:PDF
GTID:1102360242458651Subject:Nuclear science and engineering
Abstract/Summary:PDF Full Text Request
If the fuel rod damage occurs in light water reactor of Nuclear Power Plant (NPP), the radioactive fission products in the fuel will leak to the coolant in the primary loop. This will have the influence on the safety and economics of the NPP as well as on the public health. So the problem of fuel rod damage is an important international research field.The traditional method for the surveillance of fuel rod damage is manual chemical sampling, that is to extract the coolant in the primary loop and to measure theγactivity of fission products to judge whether the fuel rod damage occurs in the reactor. Due to the long sampling time, the fuel damage could not be discovered in time and the monitoring of fuel rod damage could not be continuous. The on-line fuel rod damage detecting system can overcome the disadvantages of the traditional sampling method and can continuously monitor the rod's damage in the reactor. The on-line detecting system can provide operators the information on the fuel rod damage in the reactor. So, the operators can take action as early as possible to make the economic lossing minimum.Since the 80's last century, the fuel damage issues had been paid much attention in the world. In 90's last century, the on-line fuel rod damage detecting system and the fuel damage analysis code were developed successfully, and applied in NPP. It showed that the on-line detecting has the advantages over the traditional sampling method.Based on the experience on the international research, the fuel damage on-line detecting system (FDDS-1) has been developed in this work. The FDDS-1 is first developed in China.FDDS-1 consists of hardware and software. The hardware includesγdetector,γray spectrum analyzer,γdetector cooler and personal computer. The software includes fuel damage analysis code andγspectrum analysis code. These two parts are linked together by the interface control code MONITOR. The emphasis of this paper is the development of the fuel damage analysis code.The fuel damage analysis code is the key point in the FDDS-1. The code (FUDAC-1) developed in this work adopted the international experience and the newest research fruit. The model of heat transfer in FUDAC-1 considers the transient process. The integral model considers the characteristics of the damaged fuel rod. The code has the feasibility for the on-line analysis and independent analysis.Due to the lack of the international and domestic data of fuel rod damage, it is hard to validate the FUADC-1. So, only the data from Dayabay and CHINON NPP are used in the code validation. The results of the validation showed that:(1) There is great difference between the numbers of damage fuel rods estimated by different isotopes of Kr and Xe. In the calculation of Dayabay and CHINON NPP fuel, the average method is used to estimate the number of damage fuel rods. The results showed that the number of damage rods by average method agrees very well with the actual number of damage rods.(2) The damage size of estimated by FUDAC-1 is also in good agreement with the actual size.(3) The position of the damage rods in the reactor is estimated by the relationship between the isotopes of Cs and the burnup. Due to the lack of the data of Cs isotopes from the measurement, the validation could not be made.The FDDS-1 can be used independently from the reactor primary loop. The use of FDDS-1 will not have any influence on the reactor safety. The area occupied by FDDS-1 is small about 1 m~2. These two characters of FDDS-1 made it possible and convenient to be applied in NPP.The development of FDDS-1 is only the first step of the research. To do more study on the FDDS-1 and the code FUDAC-1, it is necessary to apply them in NPP to get more improvement. So, the work for the future will be as follows:(1) The FDDS-1 should be tested in NPP as soon as possible, so the equipment of the FDDS-1 and the FUDAC-1 code could be validated. The FUDAC-1 code should be improved in order to analyze the degradation of failure rods.(2) The work of post irradiation examination (PEE) and pool side examination should be stressed to study the reasons of the fuel damage. The data from the examination will be benefit to the improvement of FUDAC-1 and to the basement for the improvement of fuel rod design.
Keywords/Search Tags:Light water reactor, Fuel rod damage, Analysis code, On-line detection
PDF Full Text Request
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