Nuclear power plant equipment maintenance

qinshan phase iii is heavy water reactor nuclear power plants in China and Canada a model of successful cooperation in the field of nuclear power. As mainland China to introduce new DuiXing, heavy water reactor nuclear power plant is the uranium fuel used natural uranium ore is very low, and high purity of heavy water as the main coolant and moderator, the reactor core using the exhaust pipe horizontal layout container, can not achieve shut down for refueling, has the very high security. In view of the characteristics of heavy water reactor, heavy water reactor nuclear power plant maintenance in addition to possess of the commonness of nuclear power plant ( Light water system and ci) Characteristics of heavy water reactor, and the itself. Advanced equipment to solve maintenance problems protective device against overpressure in the coolant and moderator heavy water reactor nuclear power plant system are separate, so that make heavy water reactor system is more than light water type of pressurized water reactor, this makes the layout of the device is very compact, the space between the equipment and equipment are relatively small, it is very important for the maintenance of reasonable use of limited space. Many devices if using the usual maintenance tools, fundamental can't satisfy the maintenance requirements, therefore, choose reasonable maintenance tools and special tools has been the maintenance staff to consider an important issue. Some important equipment, especially from the beginning of the design and manufacture were equipped with complete special maintenance tools, the effective use of these special tools, greatly improve the efficiency of maintenance and reliability, reduce the labor intensity of the maintenance staff. For equipment has not been equipped with special tools, maintenance staff to develop special tools and repair facilities, and be included in the special tool management system, so as to solve the problem for the repairing. Heavy water reactor is heavy water, use medium heavy water cost is high, medium and heavy water outflow of the spread of radioactive will cause the plant. Heavy water medium in the system is a closed loop, there is no leakage, leakage of the medium are through special airtight pipeline into heavy water recycling system. Before equipment repair needs to segregate hydrophobic can be carried out only after the equipment, staff work under the protection of reliable, for remaining a small amount of medium in the process of disintegration of the equipment, specially the heavy water collection tool collection, and transferred to the designated place to scrap recycling and accurate calculations. Recycling of heavy water medium after heavy water purification upgrade tower will re-enter play a role in the system. Repair layers of fortification any repair work there is a certain risk, how to assess and control risk, and minimize risk, especially for the nuclear power station heavy water reactor nuclear power plant maintenance is critical. Any repair work to ensure the nuclear safety from the worst start preparing measures, to ensure foolproof. First shutdown system, the second shutdown system, their own primary loop hot trap, and stop cooling system heat trap heat sink, emergency core cooling system ( ECC) , emergency water cooling system heat sink ( EWS, layers of these security system set in order to ensure the abnormal situation of nuclear safety. In order not to make the maintenance of nuclear safety due to the challenge, qinshan phase iii internal made the heat sink of repair response mechanism, some aspects is more strict than foreign similar heavy water reactor nuclear power plant, more conservative, higher safety and reliability. Qinshan phase iii adopt conservative decision make maintenance risk remained on the scope of security. In the heavy water reactor nuclear power plant overhaul, a series of advanced science and technology has been widely used. Ice jam isolation technology, large-scale equipment operation parameters online monitoring technology, laser technology, spectrum analysis technology, grating plane in the detection technology, non-destructive testing technology, etc. , as well as a variety of advanced equipment tools such as: bolt synchronization stretcher, multichannel recorder, grinding calibration equipment, pneumatic valve testing equipment. The application of advanced technology equipment and tools, complied with the modernization of heavy water reactor nuclear power plant maintenance development direction, shortened and the gap between the international advanced nuclear power plant maintenance level.