Patent Number: 050154370
Section: description

DESCRIPTION OF THE PREFERRED EMBODIMENTS The Figure illustrates a graphite core block 2 which may be assembled with a plurality of identical graphite core blocks, in the manner described above, to form a reactor core. In such a core, horizontally adjacent blocks will normally be separated by a small gap. Block 2 is shown broken away in several layers to illustrate the various flow channels therein. In accordance with the prior art, block 2 is provided with a plurality of vertical channels 4 extending throughout the height of block 2. Each channel 4 can be spaced inwardly from the edges of its associated blocks or can be formed of mating half cylinder recesses at the edges of horizontally adjacent blocks. The various core blocks are stacked atop one another so that continuous vertical channels 4 are formed to communicate with the region above and below the core. Under normal conditions, the flow of coolant, typically helium, vertically through channels 4 will provide adequate cooling of the core. However, if a blockage should develop in a channel 4, the flow of coolant through that channel will be prevented and substantial local heating can occur in the region where coolant flow no longer occurs. According to the invention, the effect of such a blockage is alleviated by the provision of a plurality of transverse channels 6 each interconnecting a row of vertical channels 4. Channels 6 extend entirely across the width of block 2 so that each channel 6 communicates with regions adjacent at opposite lateral sides of block 2 and with corresponding transverse channels in adjacent blocks. According to a further feature of the invention, each end of each channel 6 is flared, as shown in the Figure, to assure communication with corresponding channels in adjacent blocks in the event of slight misalignments between blocks. Channels 6 may be horizontal or may be inclined to the horizontal. The inclination can vary over a substantial range. If channels 6 are inclined to the horizontal, it is preferred that the inclination be small enough to assure that each channel 6 will extend between vertical sides of block 2. However, a horizontal orientation is preferred because this will simplify the task of aligning the channels in one block with those in each adjacent block. Preferably, as illustrated, transverse channels 6 are arranged in a plurality of layers, with the channels of each layer interconnecting alternate rows of vertical channels 4 and extending between two opposite faces of block 2. Each row of channels 6 extends in a direction which is transverse to the direction of the vertically adjacent layers of channels. The diameters which the channels should have to provide sufficient coolant flow can be determined according to established principles in the art. For a typical core having dimensions in the range indicated earlier herein, the vertical coolant flow channels 4, and the nonvertical channels 6 in each layer of such channels may have a center-to-center spacing of the order of 10 cm. In the illustrated embodiment, the channels 6 in each layer interconnect every other row of vertical channels 4 and the channels 6 in each layer are arranged so that each vertical channel 4 communicates with spaced layers of the nonvertical channels 6. The nonvertical channels 6 extending between two vertical sides of block 2 may be offset, from one layer of channels 6 to the next, by the spacing, perpendicular to those channels, between adjacent rows of vertical channels 4, to assure that all vertical channels 4 communicate with at least some vertically spaced nonvertical channels 6. According to one alternative embodiment of the invention, each layer of channels 6 can include a sufficient number of channels to interconnect all rows of vertical channels 4, rather than every other row as shown in the Figure. In addition, each layer of channels 6 can be oriented to extend between two side walls of block 2 other than diametrically opposed side walls. Thus, some or all of channels 6 can extend between two side walls which are separated by a single intervening side wall or can extend between two adjacent side walls. According to a further alternative, the arrangement of channels 6 illustrated in the Figure can be supplemented by auxiliary channels interconnecting any vertical channels 4 which are not interconnected by the arrangement shown. Further, if desired, two or more groups of intersecting channels 6 can be disposed in a single plane, or layer. In addition, when a core is built up from a plurality of small blocks 2, some of the channels 6 can be formed by molding semicircular recesses in the upper and lower walls of each block such that the recesses formed in vertically adjacent blocks of the core are located in registry to form channels 6 of circular cross section. The Figure further shows one large diameter vertical passage 8 which may be provided to receive a control rod or instrumentation, as is conventional in the art. While the description above refers to particular embodiments of the present invention, it will be understood that many modifications may be made without departing from the spirit thereof. The accompanying claims are intended to cover such modifications as would fall within the true scope and spirit of the present invention. The presently disclosed embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims, rather than the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.