Patent GB-992455-A (GB)
Title: Leakage prevention
IPC: G21C13/10
Filed: 1964-04-29
Abstract: 992,455. Nuclear reactors. WESTINGHOUSE ELECTRIC CORPORATION. April 29, 1964 [May 24, 1963], No. 17749/64. Heading G6C. A reactor plant enclosure comprises a sealed outer container surrounding and spaced from a sealed inner container housing the reactor and its primary coolant system, and means for maintaining the pressure in the space between the two containers lower than that within the inner container and lower than that outside the outer container and for conveying a fluid which has escaped from the plant and leaked through the inner container into the space between the two containers back into the inner container. In one embodiment (Fig. 1), the inner and outer containers 10 and 22, respectively, are of steel and the intermediate space 24, except for an exhaust space 32, is filled with particles such as gravel or crushed stone, or with a low density, pervious concrete. The sides of the exhaust space 32 are formed by perforated cylindrical screens 26, 28. Surrounding and bearing against the outer container 22 is a biological shield 36 of reinforced concrete which provides the bulk of the shielding from internal radiation sources and also the strength to withstand a pressure buildup which can result from a serious accident to the reactor plant. In alternative constructions, concrete blocks are used in place of the particles between the floors 16 and 30, respectively, of the containers 10 and 22, passages between the blocks permitting the flow of fluid between the floors, and open structural bracing is used between the inner container 10 and the outer container 22. In the latter case, the exhaust space 32 which is normally used when the space 24 is filled with a material that offers some resistance to fluid flow may be dispensed with. The use of particles in the space 24 can be eliminated by the use of a channel type or corrugated outer container 23 (Fig. 4), the inner portions 25 of which bear against the inner container 10 so as to provide the means for transmitting the internal pressure loading. In a further embodiment (Fig. 3, not shown), the reactor plant enclosure comprises inner and outer containers with only an intermediate space therebetween except for the floors which are spaced by means of concrete blocks or some type of structural steel support. In this case, however, the inner container must be made sufficiently thick to withstand any possible pressure build-up. Referring to Fig. 1, the space 24 is maintained under a pressure which is lower than either the pressure in the inner container 10 or the pressure of the atmosphere surrounding the enclosure by at least one compressor 48 outside of the enclosure and communicating with the exhaust space 32 by means of an inlet conduit 50 secured to the screen 26 and passing through the space 24 and the outer container 22. An outlet conduit 52 connects the compressor 48 with the inner space 53 of the enclosure, passing through both containers 10, 22 and the intermediate space 24. The conduits 50, 52 are sealably secured to the containers 10, 12. Arrows 58 in Fig. 1 indicate the fluid flow through the compressor system. Any leakage of fluid into the space 24 is pumped back into the inner space 53 and no leakage can occur from the space 24 to the atmosphere outside of the enclosure.