Thermovision Monitors for Nuclear Reactors
Thermovision System for Control of Nuclear Power Plant's (NPP) Equipment
Tech Area / Field
- INS-MEA/Measuring Instruments/Instrumentation
3 Approved without Funding
TsNIIKhM (Chemistry and Mechanics), Russia, Moscow
- FEI (IPPE), Russia, Kaluga reg., Obninsk
- Imatran Voima (IVO), Finland, Helsinki\nTEAM Specialty Corp., USA, NM, Albuquerque
Project summaryThe given suggestion is the second main stage of the Project. At the first research stage of the Project # 153.1 (01.07.1996 - 31.12.1996) financed by the European Community a cycle of work on technical grounding of the thermovision control system (TCS) was carried out, TSC is the system of early diagnostics and it provides operative (that is, in real-time scale) thermal control over equipment condition.
For estimating the possibility of using the thermovision method for NPP equipment control which taken as a principle of the TCS the experimental research on the base the Institute of Physics and Power Energetic (FEI) has been carried out. The research was conducted according to the following chosen list of NPP equipment and simulators to be subjected to thermal control:
• heat releasing elements (HRE) unloaded from the reactor;
• stop valves and pipe-lines of the second circuit of the NPP;
• bearings of the main circulating pump of the NPP cooling circuit;
• electric distribution boards;
• radioactive material containers (plutonium);
• pipe-lines with sodium heat-transfer agents.
For the solution of the problems of thermal control of the present list of FESL technical grounding of measuring-recording part of TCS and whole system was carried out. It includes technical approaches to conducting mathematical modeling for determining IR radiation, the control and diagnostics of heat processes, the choice of rational spectral ranges of operation, the choice of receptor unit, the working out of structural and functional schemes of stationary and mobile TCS. When conducting the experiments model specimens of universal thermovision systems (the development of Minoboronaprom and Minelectronprom mills) were used, they were chosen proceeding from the obtained estimations of operating spectral ranges. Thermal portraits of the above mentioned equipment were photographed by this measuring equipment.
For example, thermal picture of the upper bearing of external circuit of the NPP cooling fixed through the pump external jacket is given in fig. 1. Thermal picture of the container with plutonium and plutonium tablet is given in fig. 2. Fig. 1 shows that the jacket near the bearings has a warmer area, the bearing temperature can be judged from the jacket temperature. Fig. 2 shows that the external surface section of the container where there are plutonium tablets has high temperature. In fig. 2 it is seen that plutonium presence in the closed container is positively fixed. The thermal picture analysis shows that it assumes the possibility of using TCS for fulfilling the problems of preventing plunder and non-permitted carrying out of radioactive materials from the NPP.
Fig. 1. Thermal picture of the upper bearing of external circuit of the NPP cooling fixed through the pump external jacket.
Fig. 2. Thermal picture of the container with plutonium and plutonium tablet.
The experimental research of the estimation of the possibility to use the thermovision method for detecting sodium heat-transfer agent leakage from the pipe-line system has been carried out by using a double-spectral sensor on the simulator. The oscillogram analysis of signals recorded by the double-spectral meter of effective brightness showed that the temperature rise at the place of the defect up to ~ 320°C took place within 0.2 sec, the insulation inflammation occurred after 27 minutes from the moment of feeding sodium to the imperfect section of the experimental plant.
The analysis of the results of the experimental research conducted preliminary and the previous experience of the work with such thermovision units of universal application gives the right to draw a conclusion that the use of thermovision diagnostics method that is the basis of TCS allows:
• to detect thermal field anomaly in the equipment location that is difficult of access without using contact methods of control;
• to determinate the location of defect formation from the change of the field thermal image;
• to detect thermal field anomaly in the spots of raised thermal stresses;
• to carry out remote (contactless) control over radioactive heat-transfer materials in the storehouses that eliminates the possibility of fissionable material plunder;
• to provide positively early diagnostics of the developed leakage of sodium before the moment of its inflammation with subsequent formation of sodium oxides;
• to provide large amounts of information concerning the controlled situation from the point of view of the data volume received from the one sensor-converter. The aim of the Project second main stage is:
• to work out the thermovision control strategy for FESL;
• to work out the NPP thermovision control system which is the system of early diagnostics integrating into a general system of operative diagnostics of a NPP and it provides the increase the promptitude and authenticity of the present diagnostics and control system;
• the creation of the thermovision control system fragment and its experimental working out at one of operating NPP.
The thermovision control system construction in the limits of the Project (the second main stage) will be conducted using the experience gained by the collective when constructing thermal, thermovision, acoustic and other automatic systems. The processing and analysis of thermal maps obtained at the NPP in the process of fulfilling the work at the subsequent stages of the Project will be carried out using the experience gained for many years when conducting the study ofIR fields of non-stationary technical objects under conductions of their complex interaction.
Introducing the thermovision control system that will be organically integrated in the present diagnostics and control system in the NPP will provide:
1. the increase of the NPP safe operation and decreasing the degree of their ecological hazard due to introducing TCS into a general system of diagnostics, control and monitoring of NPP, it will allows promptly (in real time) to detect local fault of temperature fields and overheating which show the emergency situation coming and to take measures to prevent them timely;
2. the increase of promptitude and authenticity of NPP equipment diagnosing due to additional introducing the proposed thermovision control method which is more informative and provides objective measurement of temperature fields, promptitude and clearness of their representation in comparison with the contact methods used at present;
3. the increase of the reliability of radioactive material (plutonium) storage in containers, it will result in preventing the material stealing due to non-destroying (thermal) control of containers.
A number of new technology methods will be used when developing the thermal control system (e.g. the technology of constructing a cooling assembly based on Peltier's effect) using a metal-dielectric base of aluminium with a dielectric polymer layer applied to it. This technology was awarded a gold medal at the exhibition "Evrika-94" in Brussel.
"Imatran Voima Oy" firm (Finland) and VVT Technical Research Centre of Finland have agreed to be foreign collaborators of this Project. "Imatran Voima Oy" firm expressed an interest of this kind of new technology development for detection of leaks and also the wish to perform tests with new equipment of thermal control. The invitation to visit the firm for participants of the Project for discussion of results of the experimental research carried out at first research stage of the Project was received from "Imatran Voima Oy" firm.
Team Specialty Products Corp., Sandia National Labs (USA) has agreed to be foreign collaborator of the Project and to promote the system marketing.
The participants of the suggestion of the Project # 153.2 presented to ISTC (the second main stage) are interested in the evaluations of the work they are conducted and would be grateful to all foreign firms for the analysis and discussion of the work results obtained in the course of Project fulfilling.
If foreign firms take interest in the problem of early diagnostics of the equipment condition participants of the Project invite them to be a foreign collaborator in it without any financial support from their side.