The present article reviews different patented devices of heat-fire protection system of pipeline and cable duct of bulkhead having used fibrous and retardant intumescent materials. Their structures and fillers are considered, benefits and drawbacks are defined. The improved design for duct of bulkhead is offered. It is characterized by advanced equipment reliability, technological and fire retardance effectiveness. It is specially noted that breakthrough fire-fighting technology is introduced in the new device. It implies the usage of fire retardant material, providing with thixotropic properties or high viscosity. In proof of the device efficiency the article reviews the experiment conducted on the model of a fire-retardant device.
In the last few years the cold collectors in the PGV-1000 steam generators have been cracking in nuclear power plants with BBER-1000 reactors. The reasons for this phenomenon are not completely understood. The deficiencies of the design of the cold collector, the technology of fabrication of the collector, and the operation of the collector are mainly investigated. However, thermal hydraulic processes occurring in the collector itself or near it can have a negative effect on the crack resistance. The thermal hydraulic stability of the motion of the vapor-liquid flow in the interpipe space of steam-generating pipe bundles apparently have not been studied at all because of the difficulty of describing the motion of the flow of water and steam in the volume of the steam generator.Sections of the bundles of the horizontal pipes with two-dimensional motion of water in the interpipe space can be distinguished on the basis of the structural peculiarities of the PGV-1000 steam generators. The freedom of motion of the liquid in the third direction is prevented by the supporting metallic braiding. For this reason, we shall consider a bundle of horizontal pipes with water moving in two directions z and x: vertical and across the pipe bundle. There is no water motion in the interpipe space in the direction along the pipe bundle. To construct a mathematical model of such a pipe bundle, we shall make several additional assumptions: Inside the pipes the warming heat carrier moves with the same velocity: the temperature of the ,arming heat carrier is the same in all pipes and does not change along the section of the pipe bundle separated out: the steamliquid flow in the interpipe space is assumed to be homogeneous; the water volume around the pipe bundle is large, so that here the velocity of the water is very low: the pipe bundle is assumed to be a porous body with volume heat release and volume-averaged coefficient of friction.We shall describe the thermal hydraulic processes occurring in the interplpe space of the pipe bundle by the equations of conservation of mass, energy, and momentum in projections along two directions [1]:
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