公开(公告)号：US4401608A

公开(公告)日：1983-08-30

申请号：US310619

申请日：1981-10-13

申请人： Peter C. Smith

发明人： Peter C. Smith

IPC分类号： C04B35/51 ,  C01G43/01 ,  C01G43/025 ,  G21C3/62 ,  G21C21/00

CPC分类号： C01G43/025 ,  G21C3/623 ,  C01P2004/61 ,  Y02E30/38

摘要： The grain size of particulate uranium oxides is increased and adjusted by the application thereto of hydrogen peroxide. The procedure is useful in the manufacture of nuclear reactor fuel from powdered fissionable materials.

摘要翻译： 颗粒状氧化铀的颗粒尺寸通过过氧化氢的应用而增加并调整。 该方法可用于从粉状可裂变材料制造核反应堆燃料。

公开(公告)号：US4152395A

公开(公告)日：1979-05-01

申请号：US801245

申请日：1977-05-27

申请人： Paul Borner ,  Hans-Jorg Isensee ,  Horst Vietzke

发明人： Paul Borner ,  Hans-Jorg Isensee ,  Horst Vietzke

IPC分类号： C01G43/01 ,  C01G43/025 ,  C01G43/02

CPC分类号： C01G43/025 ,  C01G43/01 ,  C01P2004/32 ,  C01P2004/50 ,  C01P2004/61 ,  C01P2006/10 ,  C01P2006/12 ,  C01P2006/20 ,  C01P2006/80 ,  C01P2006/82

摘要： There is provided a process for the production of pourable, directly compactable uranium dioxide powder by continuous precipitation of uranium peroxide from a stirred uranyl nitrate solution at a pH of 1 - 2.5 with hydrogen peroxide, calcining of the peroxide at 500.degree.- 800.degree. C. and subsequent reduction at 550.degree.- 750.degree. C. The precipitation solution contains 70 - 150 g/l of uranium and 0.80 g/l of ammonium nitrate and is treated with 15 - 20% aqueous hydrogen peroxide solution in the ratio of U:H.sub.2 O.sub.2 from 1:1.5 to 1:3 and there is led through the solution a mixture of ammonia and air having an air-ammonia volume ratio of 1:0.3 - 0.6. An apparatus for carrying out the process is also described. SUBACKGROUND OF THE INVENTIONThe present invention is directed to a process and apparatus for the production of directly pressable (moldable) uranium dioxide powder from uranium peroxide (UO.sub.4.xH.sub.2 O) which is continuously precipitated from uranyl nitrate solution whereby by variation of the precipitation conditions as well as the temperature in the subsequent calcination and reduction the properties of the UO.sub.2 powder are so regulated that in the pressing and sintering of tablets (pellets) it is possible to vary the sintered density in the large range of 75-95% of the theoretical density without additional conditioning steps such as plasticizing, granulating or sieving.In order to take steps against the swelling of the fuel at the higher burn-up rates in modern light water reactors, the sintered density in the UO.sub.2 pellets has been reduced from 95% of the theoretical density partially up to 90%. Such a variation of the sintered density is not possible with the previously known processes for the production of uranium dioxide and of the thus obtained powders. The future reactor generation, the sodium cooled breeder reactor, however, must contain pellets with a sintered density of only 80-85% of the theoretical density. For this purpose, the presently known processes for the production of uranium dioxide powder must employ a conditioning of the UO.sub.2 powders. Either the entire UO.sub.2 powder must be subsequently calcined at 1100.degree.-1400.degree. C. or be mixed with a large portion of highly calcined UO.sub.2. Such powders, however, are inclined partially to resintering which cannot be permitted for the operation of the reactor since the fuel elements are damaged thereby.There have become known a series of precipitation processes according to which sinterable UO.sub.2 is produced from uranyl nitrate solutions. However, there are only a few processes, as, e.g., via the precipitation of ammonium uranyl carbonate, with which it is possible to produce a free-flowing UO.sub.2 powder which permits a direct pressing of UO.sub.2 pellets without pretreatment. With all known processes, however, there is formed a UO.sub.2 powder from which there can only be produced pellets with relatively high sintered density.Therefore, it was the problem of the present invention to find a process and apparatus for the production of a free-flowing uranium dioxide powder which could be directly compacted and worked to pellets with an adjustable sintered density of 75-95% of the theoretical density without granulating or other aftertreatment.SUMMARY OF THE INVENTIONThis problem was solved by producing the uranium dioxide powder by continuous precipitation of uranium peroxide from uranyl nitrate solution with hydrogen peroxide, calcining the peroxide at 500.degree.-800.degree. C. and subsequently reducing it at 550.degree.-750.degree. C. According to the invention, the precipitation solution contains 70-150 g/l of uranium and 0-80 g/l of ammonium nitrate. To this solution there is added a 15 to 20% aqueous hydrogen peroxide solution in the ratio of U:H.sub.2 O.sub.2 of from 1:1.5 to 1:3 and there is led through the solution an ammonia-air mixture with an air to ammonia volume ratio of 1:0.3 to 1:0.6. The pH of the solution must be adjusted to 1-2.5 and additionally the reaction mixture is stirred. When ammonium nitrate is employed, it usually is present in an amount of at most 80 g/l.Preferably the precipitation solution contains 90-120 g/l of uranium, is treated with a 17.5% hydrogen peroxide solution, and an air-ammonia mixture having a volume ratio of 1:0.45 is led through and the pH is adjusted to 1.5-2.It is especially advantageous if the circulation rate of the reaction mixture is regulated to such an extent by the stirring that the entire volume of liquid passes the stirrer 2-4 times a minute, preferably 3 times a minute, when the ammonia-air mixture is led in at a distance of 80-120 mm, preferably 100 mm above the inlet of the uranyl nitrate and the H.sub.2 O.sub.2 solution is introduced 40-60 mm, preferably 50 mm above the inlet for the ammonia-air mixture.The uranyl nitrate solution used generally contains 0.5 N free HNO.sub.3 and is preferably produced by dissolving U.sub.3 O.sub.8 with HNO.sub.3. These solutions are used to produce less sinterable UO.sub.2 powder, i.e., for the production of pellets with lower sintered density, for production of highly sinterable UO.sub.2 powder (i.e., high sintered density), there is added to the precipitation solution up to 80 g/l of ammonium nitrate.The calcining can take place in air. The reduction takes place using a conventional reducing medium, e.g., hydrogen.The flowability and sintering properties of the UO.sub.2 powder are primarily influenced by the shape of the uranium peroxide precipitate. This must be spherical and remain constant during the entire time of precipitation. The uniformity of the precipitation is obtained by using a special precipitation apparatus.

摘要翻译： 并通过该溶液引导空气与氨的体积比为1:0.3至1:0.6的氨 - 空气混合物。 溶液的pH值必须调至1-2.5，另外搅拌反应混合物。 当使用硝酸铵时，其通常以至多80g / l的量存在。

公开(公告)号：US4053559A

公开(公告)日：1977-10-11

申请号：US695346

申请日：1976-06-14

申请人： James E. Hart ,  David L. Shuck ,  Ward L. Lyon

发明人： James E. Hart ,  David L. Shuck ,  Ward L. Lyon

IPC分类号： C01G43/01 ,  C01G43/025 ,  G21C3/62 ,  C01G43/02 ,  G21C3/00

CPC分类号： C01G43/025 ,  C01G43/01 ,  C01P2004/51 ,  C01P2004/61 ,  C01P2004/62 ,  C01P2006/80 ,  Y02P20/129

摘要： A continuous, four stage fluidized bed process for converting uranium hexafluoride (UF.sub.6) to ceramic-grade uranium dioxide (UO.sub.2) powder suitable for use in the manufacture of fuel pellets for nuclear reactors is disclosed. The process comprises the steps of first reacting UF.sub.6 with steam in a first fluidized bed, preferably at about 550.degree. C, to form solid intermediate reaction products UO.sub.2 F.sub.2, U.sub.3 O.sub.8 and an off-gas including hydrogen fluoride (HF). The solid intermediate reaction products are conveyed to a second fluidized bed reactor at which the mol fraction of HF is controlled at low levels in order to prevent the formation of uranium tetrafluoride (UF.sub.4). The first intermediate reaction products are reacted in the second fluidized bed with steam and hydrogen at a temperature of about 630.degree. C. The second intermediate reaction product including uranium dioxide (UO.sub.2) is conveyed to a third fluidized bed reactor and reacted with additional steam and hydrogen at a temperature of about 650.degree. C producing a reaction product consisting essentially of uranium dioxide having an oxygen-uranium ratio of about 2 and a low residual fluoride content. This product is then conveyed to a fourth fluidized bed wherein a mixture of air and preheated nitrogen is introduced in order to further reduce the fluoride content of the UO.sub.2 and increase the oxygen-uranium ratio to about 2.25.

公开(公告)号：US3993578A

公开(公告)日：1976-11-23

申请号：US444773

申请日：1974-02-22

申请人： Panayotis Gerontopoulos ,  Carlo Fantuz

发明人： Panayotis Gerontopoulos ,  Carlo Fantuz

IPC分类号： C01G43/01 ,  B01J2/02 ,  B01J2/04 ,  B01J2/08 ,  B27L1/05 ,  C01G43/025 ,  C04B35/628 ,  G21C3/62 ,  G21C3/54

CPC分类号： G21C3/62 ,  B01J2/08 ,  Y02E30/38

摘要： In the preparation of microspheres of nuclear fuel by feeding droplets of an aqueous solution of a salt of a metal constituting the nuclear fuel that is precipitated by a basic medium and a resin that increases in viscosity in the presence of an alkali into an aqueous alkaline solution so that spheroids are formed therefrom which are then dried and calcined, the geometrical properties of those spheroids are controlled by thermostating the feed solution so that the droplets which are fed into the alkaline solution have a predetermined temperature.

摘要翻译： 在通过将由碱性介质沉淀的构成核燃料的金属的盐水溶液和在碱存在下使粘度增加的树脂的水溶液滴入碱性水溶液的制备中而制备核燃料的微球时， 从而由此形成球体，然后将其干燥和煅烧，通过恒温进料溶液来控制那些球体的几何性质，使得进料到碱性溶液中的液滴具有预定温度。

公开(公告)号：US3845193A

公开(公告)日：1974-10-29

申请号：US34087573

申请日：1973-03-13

申请人： ATOMIC ENERGY AUTHORITY UK

发明人： LITTLECHILD J ,  GILLIES G

IPC分类号： C01G43/025 ,  C01G43/02

CPC分类号： C01G43/025 ,  C01P2006/10

摘要： 1. A PROCESS FOR THE CONVERSION OF URANIUM HEXAFLUORIDE TO URANIUM DIOXIDE WHICH COMPRISES INJECTING URANIUM HEXAFLUORIDE VAPOR INTO AN UPPER END OF A PROCESS VESSEL COMPRISING AN INCLINED ROTARY BARREL TYPE KILN, REACTING SAID URANIUM HEXAFLUORIDE VAPOR IN SAID UPPER END WITH DRY STEAM TO FORM A PLUME OF URANYL FLUORIDE POWDER, SAID PLUME BEING DIRECTED TOWARDS THE UPPER END OF THE BARREL OF THE LILN SO THAT THE MAJORITY OF THE URANYL FLUORIDE PRODUCED IS DEPOSITED DIRECTLY IN THE UPPER END OF THE BARREL OF THE KILN AND CONVERTING URANYL FLUORIDE POWDER TO URANIUM OXIDE POWDER BY REACTING THE URANYL FLUORIDE PASSING DOWN THE BARREL OF THE KILN WITH A REACTANT SELECTED FROM THE GROUP CONSISTING OF STEAM, HYDROGEN AND A STEAM/HYDROGEN MIXTURE, SAID REACTANT PASSING IN COUNTERCURRENT FLOW TO THE URANYL FLUORIDE, AT A TEMPERATURE HIGHER THAN THE TEMPERATURE IN SAID UPPER END AND SUFFICIENT TO CONVERT SAID URANYL FLUORIDE POWDER TO URANIUM DIOXIDE.

公开(公告)号：US3842155A

公开(公告)日：1974-10-15

申请号：US20085771

申请日：1971-11-22

申请人： NUKEM GMBH

发明人： HACKSTEIN K ,  MULLER H ,  PIRK H

IPC分类号： C01B15/047 ,  C01C1/12 ,  C01G43/00 ,  C01G43/01 ,  C01G43/025 ,  C01G43/06 ,  C01F15/00

CPC分类号： C01G43/025 ,  C01B15/0475 ,  C01C1/12 ,  C01G43/00 ,  C01G43/01 ,  C01G43/06

摘要： 1. IN A PROCESS FOR THE SIMULTANEOUS RECOVERY OF NH3, CO2 AND FLUORIDE FROM NH4+, CO3= AND FLUORIDE CONTAINING FILTRATE FROM THE PRECIPITATION OF TETRAAMONIUM URANYKL TRI CARBONATE THE IMPROVEMENT COMPRISING A FIRST PHASE OF A CIRCULATORY PROCESS REACTING SAID FILTRATE WITH A STRONGLY ACID AQUEOUS SOLUTION OF AMMONIUM FLUORIDE AND AMMONIUM HYDROGEN FLUORIDE, LIBERATING CARBON DIOXIDE AND BINDING AMMONIA AND REDUCING THE ACIDITY OF SUCH REACTION, REMOVING THE LIBERATE CARBOM DIOXIDE FROM THE FILTRATE, IN A SECOND PHASE OF THE CIRCULATORY PROCESS CONTINUOUSLY EVAPORATING THE WEAKLY ACID AND CARBONATE FREE SOLUTION SO FORMED AND THEREBY SETTING FREE AMMONIA, REMOVING THE AMMONIA SET FREE AND THEREBY REGENERATING THE STRONGLY ACID SOLUTION, MAINTAINING THE FLUORIDE CONTENT OF THE CIRCUIT CONSTANT BY WITHDRAWING FROM THE CIRCUIT SUFFICIENT OF THE STREAM OF STRONGLY ACID SOLUTION TO PREVENT INCREASE IN FLUORIDE, PRECIPITATING URANIUM FROM THE SAID WITHDRAWN STREAM BY ADDING AMMONIA AND HYDROGEN PEROXIDE AND REMOVING FLUORIDE IONS FROM THE REMAINING WITHDRAWN STREAM BY PRECIPITATING THE FLUORIDE AS INSOLUBLE CALCIUM FLUORIDE BY ADDING A CALCIUM COMPOUND WHICH IS CALCIUM OXIDE OR CALCIUM HYDROXIDE.

公开(公告)号：US3814327A

公开(公告)日：1974-06-04

申请号：US13168471

申请日：1971-04-06

申请人： GEN ELECTRIC

发明人： DADA A

IPC分类号： B01J4/00 ,  B01J19/26 ,  C01B13/22 ,  C01G43/025 ,  F23D14/00 ,  B05B7/00

CPC分类号： C01G43/025 ,  B01J4/001 ,  B01J19/26 ,  B01J2219/00157 ,  C01B13/22 ,  F23D14/00

摘要： A nozzle for injecting fluid reactants into a reaction zone is presented in various embodiments. The nozzle is held by a supporting means and has a first inlet means for receiving and guiding a first fluid reactant into the reaction zone. The nozzle has a second inlet means for receiving and guiding a shielding fluid into the reaction zone for temporarily separating the fluid reactants entering the reaction zone. A third inlet means is disposed and slightly recessed within the second inlet means and has a chamber for receiving a second fluid reactant which chamber is connected preferably to a plurality of tubular members for guiding the second fluid reactant into the reaction zone. A directional control plate is secured transversely in the second inlet means and this plate is provided with openings through which the plurality of tubular members extend coaxially forming an annular opening around each tubular member enabling the shielding fluid in the second inlet means to flow unidirectionally through the annular openings and then into the reaction zone.

摘要翻译： 在各种实施例中呈现用于将流体反应物注入反应区的喷嘴。 喷嘴由支撑装置保持，并具有用于接收和引导第一流体反应物进入反应区的第一入口装置。 喷嘴具有用于接收和引导屏蔽流体进入反应区域以暂时分离进入反应区域的流体反应物的第二入口装置。 第三入口装置设置并稍微凹入第二入口装置内，并且具有容纳第二流体反应物的室，该室优选地连接到用于将第二流体反应物引导到反应区中的多个管状构件。 方向控制板横向地固定在第二入口装置中，并且该板设置有开口，多个管状构件通过该开口同轴地延伸，围绕每个管状构件形成环形开口，使得第二入口装置中的屏蔽流体能够单向流过 然后进入反应区。

公开(公告)号：US3801701A

公开(公告)日：1974-04-02

申请号：US3801701D

申请日：1970-05-18

申请人： UNISEARCH LTD

发明人： ROBINS R ,  EDENBOROUGH B

IPC分类号： C01G43/025 ,  G21C3/62 ,  C01G43/02

CPC分类号： C01G43/025 ,  C01P2006/80

摘要： AN IMPROVED PROCESS FOR THE PRODUCTION OF URANIUM DIOXIDE BY THE REDUCTION OF AN ACID SOLUTION OF A URANYL SALT, PREFERABLY THE SULPHATE, NITRATE, CHLORIDE, ACETATE OR PERCHLORATE, OR A MIXTURE OF ANY OF THESE SALTS, WITH A CARBOHYDRATE, SUCH AS SUCROSE, D-GLUCOSE, D-FRUCTOSE, STARCH OR A SACCHARIDE, AT A TEMPERATURE OF BETWEEN 60* C. AND 300*C. UNTIL THE URANYL SOLUTION IS REDUCED TO URANIUM DIOXIDE.

公开(公告)号：US3728274A

公开(公告)日：1973-04-17

申请号：US3728274D

申请日：1969-12-05

申请人： SNAM PROGETTI

发明人： GERONTOPOULOS P ,  NERI D ,  RENZONI R

IPC分类号： B01J2/08 ,  C01G43/025 ,  C01G56/00 ,  C09K3/00

CPC分类号： B01J2/08 ,  C01G43/025 ,  C01G56/004 ,  C01P2004/32 ,  C01P2006/14

摘要： THIS INVENTION RELATES TO A PROCESS FOR THE PRODUCTION OF A POROUS REFRACTORY MATERIAL WHICH COMPRISES URANIUM OXIDE AND AN OXIDE SELECTED FROM THE GROUP CONSISTING OF THE OXIDES OF THORIUM, PLUTOMIUM, BERYLLIUM, SILICON, ALUMINUM AND MAGNESIUM, WHICH PROCESS COMPRISES HEATING THE REFACTORY MATERIAL IN AN INERT OR OXIDIZING ATMSOPHERE, REPLACING THE INERT OR OXIDIZING ATMOSPHERE BY A REDUCING ATMOSPHERE, FURTHER INCREASING THE EMPERATURE OF THE HEATED REFRACTORY MATERIAL TO PRODUCE A MATERIAL HAVING POROSITY OF FROM 2% TO 30%.

公开(公告)号：US3535264A

公开(公告)日：1970-10-20

申请号：US3535264D

申请日：1967-07-05

申请人： NUKEM GMBH ,  KERNFORSCHUNGSANLAGE JUELICH

发明人： HACKSTEIN KARL-GERHARD ,  FLEISCHHAUER GERHARD ,  NOWAK JURGEN

IPC分类号： B01J2/08 ,  C01B31/30 ,  C01F15/00 ,  C01G25/02 ,  C01G43/00 ,  C01G43/025 ,  G21C3/62 ,  G21C3/04

CPC分类号： G21C3/62 ,  B01J2/08 ,  C01B32/90 ,  C01F15/00 ,  C01G25/02 ,  C01G43/00 ,  C01G43/025 ,  C01P2004/32 ,  C01P2006/10 ,  Y02E30/38