Patent Number: 040452859
Section: description

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS FIGS. 1 and 2 show an explosion-proof, pressure-tight safety vessel 1 of cylindrical shape made of reinforced concrete. Centrally inside the safety vessel are arranged a helium-coated high-temperature reactor 2 having ball-shaped fuel elements, together with the components of the primary circuit (the tubular cracking ovens, steam generators, blowers, gas lines, and the secondary cooling systems) as well as the recuperative heat-exchangers, which shall be further described below. The high-temperature reactor 2 is built into a cavity 3. Above the reactor cavity is shown a collection chamber 4 in which the cold helium is accumulated prior to being fed into the reactor. Underneath the floor of the reactor core a pillared collection chamber 5 is provided, wherein the exiting helium is accumulated after being heated in the core. The nuclear reactor 2 is connected to the primary circuit by four symmetrically and radially installed inlet and outlet pipes. In a circle around reactor cavity 3, four perpendicular pods 6, 7, 8, 9 are arranged, spaced symmetrically 90.degree. with respect to each other. Parallel thereto are arranged four additional perpendicular pods 10, 11, 12, 13, likewise spaced symmetrically to each other but on a circle of larger radius (than pods 6, 7, 8, 9) around cavity 3. These large passageways, which like the reactor cavity 3 are encased in heat-insulated and water-cooled steel liners, are capped by explosion-proof lids 15, which are secured with an excess number of fasteners. In a circle of even larger radius, four additional pods 20, 21, 22, 23 are provided, likewise positioned symmetrically at 90.degree. with respect to one another around cavity 3. These pods have a relatively small diameter and are closed on top and at the bottom by explosion-proof lids 24, 25. The pods are likewise lined with heat-insulated steel liners 14. In each of the four pods 6, 7, 8, 9, a tubular cracking oven 16 is installed on the same level as the reactor core. Each tubular cracking oven 16 is connected to a steam generator 17 installed in pods 10, 11, 12, 13. Underneath each steam generator 17 in pods 10, 11, 12, 13 a blower assembly 18 is installed comprising a single-stage axial blower, as shown in FIG. 2. In each of the pods 20, 21, 22, 23, a recuperative heat exchanger 19 is installed, each of which is connected to one tubular cracking oven 16. The tubular cracking ovens 16, the steam generators 17, and the recuperative heat exchangers 19 are accessible for removal from the top, while contrariwise, blower assemblies 18 are easily removed from below. The pods 6, 7, 8, 9 are each connected to reactor cavity 3 by a horizontal passageway 26 in which is installed coaxial gas duct 27, wherein the hot exhaust gas from the reactor streams through the inner coaxial duct 28, and the gas entering the reactor passes through the outer annular conduit 29. Then in the annular space 30 between the high-temperature reactor 2 and the reactor cavity 3 the gas passes to collection chamber 4. The tubular cracking ovens 16 are each suspended from a support plate 31 which is firmly attached by flanges to liners 14 inside each pod. The joint between the support plates 31 and the liner 14 is tightly sealed, creating the chamber 32 which is completely separated from the tubular cracking oven. Chamber 32 is charged with pure helium gas at a somewhat higher rate of pressure than that of the primary gas. Horizontal passageways 33 are installed below the support plates 31 of tubular cracking ovens 16; then connect pods 6, 7, 8, 9 with the adjacent pods 10, 11, 12, 13. In passageways 33, coaxial gas tubes 34 are also installed. The gas streams out of the tubular cracking ovens 16 in the inner tubes 35 to the steam generators 17, whereas the relatively cold gas, after being compressed by compressor 18, passes through the outer annular space 36 back to the high-temperature reactor 2. The entire primary circuit is therefore split up into four identical loops, which are combined via nuclear reactor 2 and each of which comprises a tubular cracking oven 16, a steam generator 17, a blower assembly, and the corresponding system of gas lines. Above the support plates 31 of each tubular cracking oven 16, a horizontal passageway 37 is provided which connects pods 6, 7, 8, 9 each with respective pods 20, 21, 22, 23. In each passageway 37 a coaxial duct 38 is installed comprising an inner conduit 39 and an outer annular conduit 40, through which the process gas is moved toward the tubular cracking oven 16. The hot cracking gas passes through the inner ducts 39 from the tubular cracking oven 16 to the recuperative heat exchanger 19. Four additional pods 41, 42, 43, 44 are provided which are symmetrically installed in a circle having a smaller radius than that of pods 6, 7, 8, 9. Pods 41, 42, 43, 44 are installed at 90.degree. angles and serve as receptacles for the secondary cooling system 45 which is not shown in detail. This secondary cooling system 45 is connected to nuclear reactor 2 by a radial, coaxial gas duct 46 and has the capacity of disposing of 50% of the residual fission heat. The tubes connecting the recuperative heat exchangers 19 to the components for the gasification of coal (not shown) are installed in the lids 25 of pods 20, 21, 22, 23. The methane/steam mixture passes through pipe 47 into pods 20, 21, 22, 23. It streams through annular conduit 48 into the space between the liners 14 and the coaxial ducts 51 before passing into the recuperative heat exchangers 19 through which it flows on the shell side. The mixture then passes through the exterior tubes 40 of the coaxial duct 38 to the tubular cracking ovens 16 from where it is brought to a distributor chamber 49 in each loop. Here the mixture is fed into a plurality of cracking tubes which are welded into the support plate 31. The gas, after being cracked, is collected in accumulation chamber 50 from where it passes through the interior tube 39 of the coaxial system 38 into the recuperative heat exchanger 19. The cracking gas is distributed over the tubes of the heat exchangers 19 by distributor heads 59. It flows in downward direction and is then fed through collector heads 60 into the coaxial ducts 51 installed in the lower sections of pods 20, 21, 22, 23. Coaxial ducts 51 subsequently pass out of the concrete pressure vessel 1 through lids 25 and are extended outwardly so as to connect the system with the components for the gasification of coal. For the purpose of replacing the catalyst contained in the cracking tubes, the chambers 32 above support plates 31 in pods 6, 7, 8, 9 are made easily accessible by means of access passages 52 set into pod covers 15. The pipes connecting the steam generators 17 with the steam turbine assemblies (now shown) are installed so as to pass through the lids 15 of pods 10, 11, 12, 13. The water supply passes through pipes 53 into the distributors 54 where it is distributed over a plurality of steam-generating tubes. After being vaporized and subsequently superheated in the steam generators 17, the steam is collected in collector chambers 55 from where it passes through pipes 56 to the steam turbine assembly. In the following, the circuit of the primary gas through the reactor and the circuit of the process gas through one of the tubular cracking ovens is once again summarized, limiting the description to one of the four identical loops. The cold helium gas is brought into accumulator chamber 4 above the reactor core at a temperature of 420.degree. C. and at a pressure of 39.9 bar. It then flows downwardly through the reactor core absorbing heat, and is collected in the pillared collection chamber 5. It is then distributed over the four parallel loops via the four reactor outlet pipes. The helium gas heated to 930.degree. and at a pressure of 39.2 bar enters, from below, through hot-gas duct 28 into the tubular cracking oven 16 where it is cooled down to a moderate temperature by the process gas moving through the cracking tubes in the opposite direction. The primary gas is brought through the inner coaxial tube 35 of connecting duct 34 to the steam generator 17, entering into it at a temperature of 780.degree. C. and at a pressure of 39.1 bar. It flows through it also on the shell side, but from top to bottom. In its passage through steam generator 17, the gas is cooled by the oppositely flowing water being vaporized. The gas streams out of the steam generator 17 at a temperature of 400.degree. C. and at a pressure of 38.7 bar and is then compressed by blower 18 to the highest pressure applied in the circuit, 40 bar, whereas its temperature is now 410.degree. C. The gas is returned from the blower 18 to the nuclear reactor through the exterior tubes of the coaxial pipes and on its path flows around all the components comprising the primary circuit, including the hot-gass pipes. The relatively cold gas passing out of blower 18 moves through the annular duct 57 installed in the space between the steam generator 17 and the steel liner 14 in an upward direction in its pod. The gas is brought into pods 6, 7, 8, 9 through the outer tube 36 of the coaxial duct 34 which connects each of pods 6, 7, 8, 9 to its respective counterpart, 10, 11, 12, 13. The gas then moves downwardly through the annular conduit 58 formed by the space between the tubular cracking oven 16 and the steel liner 14 in each pod, and then enters into the reactor cavity by way of the exterior annular conduit 29 in the horizontal passageway 26. Subsequently the helium gas passes through the annular space 30 between the high-temperature reactor 2 and reactor cavity 3 to accumulation chamber 4. In the recuperative heat exchangers 19, the methane/steam mixture is heated to 650.degree. C. and then brought to the tubular cracking ovens 16 at this temperature and at a pressure of 43 bar. The gas, after being cracked, emerges, having the temperature of 820.degree. C. and a pressure of 40 bar. In passing through the heat exchanger 19 the cracking gas gives off some of its heat to the methane/steam mixture and moves out of the heat exchangers at a temperature of approximately 520.degree. C. The temperature of the water supply fed into the steam generators is 170.degree. C., while the temperature of the live steam is 510.degree. C. The chamber 32 above the support plate 31 in all the tubular cracking ovens 16 is filled with pure helium at a pressure of 41 bar.