Method for producing nickel-63 radionuclide
FIELD: production of radioactive isotopes.
SUBSTANCE: proposed method for producing nickel-63 radioactive isotope from target within reactor includes production of nickel-62 enriched nickel target, irradiation of the latter in reactor, and enrichment of irradiated product with nickel-63, nickel-64 content in nickel-62 enriched target being not over 2%; in the course of product enrichment with nickel-63 nickel-64 isotope is extracted from irradiated product.
EFFECT: enlarged scale of production.
1 cl, 2 tbl
The invention relates to the field of production of radioactive isotopes, and more specifically to a technology for production of radioactive isotopes in the reactor from the target, pre-enriched need a stable isotope. Radioactive isotopes are used in various fields. In particular, the isotope Nickel-63 is used as a radiation source in chambers on the detection of explosives.
Isotopes of an element is defined by the mass of available stable isotopes and their contents in the natural mixture. The mass of the isotopes is measured in atomic mass units [Amu]. A Nickel there are five stable (non-radioactive) isotope and the table below shows their natural prevalence (Ipeline. "Isotopes". The Handbook. M.: Nauka, 1970).
When placing a Nickel in a nuclear reactor, the neutrons interact with the isotopes of Nickel, and Nickel-62 is formed of radioactive Nickel-63. However, small natural Nickel-62 is not possible to achieve high specific activity of Nickel-63.
the La increase output using the target enriched need initial stable isotope. The known process of obtaining isotopes of Nickel, which is used as a target Nickel-rich Nickel-62 (Assersion, Tsaritsa, Aphrodi. Reference education nuclides in nuclear reactors. M, Energoatomizdat, 1989) Development of centrifugal technology for isotopes of Nickel allows you to get the isotopes of Nickel in sufficient quantities. (L.J.Sosnin, I.A.Suvorov, A.N.Tcheltsov, A.I.Rudnev. Investigation of centrifuge enrichment of stable nickel isotopes. Nuclear Instruments and Methods in Physics Research, 1993, v.A334, p.41-42.)
Known and used process gas centrifugation on an industrial scale was developed for the separation of isotopes of uranium (see, for example, "uranium Enrichment", as amended Spillane. M.: Energoatomizdat, 1983). To effect the separation of volatile connection element serves in a rapidly rotating rotor and heavier molecules containing the heavier isotopes are concentrated in the periphery, resulting in the separation effect (see, for example, Chemla, Jpare "isotope Separation), Atomizdat, 1980). To achieve the effect of separation in the gas phase using special high-speed centrifuge, whose speed many times greater than the other counterparts.
In addition to the separation of isotopes of uranium, centrifugal technology developed in the Annex to the division of the article is stable isotopes of other chemical elements - iron, tungsten, xenon, sulfur, molybdenum and others ("Nuclear energy", volume 67, No. 4, Oct, str). The main condition of applicability of the method is the element of volatile chemical compounds with a sufficient vapor pressure. For the separation of isotopes of Nickel use tetrofosmin Nickel - Ni(PF3)4.
However, the application of even enriched target is not always possible to obtain a sufficient specific activity of the radioisotope in the source material. In the case of Nickel-63 this is caused by a not very high rate of accumulation, and burnout Nickel-63, as he when exposed to a neutron goes into a stable Nickel-64.
Operating in the country, centrifugal technologies to allow for enrichment and radioactive isotopes. The centrifugal method increased the specific activity of iron-55, tin-119m and other radioisotopes. The content of the radioisotope can be brought close to 100%, and this corresponds to the higher specific activity of radioactive material.
Known sequence of operations, including obtaining enriched target isotope source material irradiated in a reactor, the conversion of the volatile compound and subsequent enrichment radioisotope applied to Nickel-63 are listed in the "Obtaining63Ni high specific activity" (L.J.Sonin, I.A.Suvorov, A.N.Tcheltsov, B.I.Rogozev, V.I.Gudov. Production of63Ni of high specific activity. Nuclear Instruments and Methods in Physics Research, 1993, v.A334, p.43-44.), which is selected as a prototype. Starting isotope Nickel-62 is enriched to a concentration of more than 99%, is placed in a high-flux reactor SM-2 (neutron flux of 1.75×1015n/cm2·sec). After accumulation of Nickel-63 is enrichment.
The disadvantage of the method of producing a radionuclide Nickel-63 prototype are the limiting characteristics of the two components - the degree of enrichment of the target and the neutron flux. These options allow you to get a unique product that economic indicators can not find wide application.
One of the applications of Nickel-63 can be used in self-contained source of electrical energy based on the beta voltaic effect. Beta voltaic effect is analogous to the photoelectric effect, with the difference that the formation of electron-hole pairs in a semiconductor with a p-n transition occurs under the action βparticles instead of light radiation. A radioactive isotope of Nickel-63 is clean βemitter (no associated harmful gamma radiation and has a half-life of 100 years. So this is one of the most promising radionuclide for sources of electrical energy with a lifetime of more than 30 years (ATO the different batteries).
For this application Nickel-63 should be made in sufficient quantities and at an acceptable cost. The high-flux reactor CM-2 used to not be, because the amount for the accommodation of small targets (several liters), and the value of the neutron flux is too high. Another disadvantage of the prototype is the high cost of enrichment of the target with 99% Nickel-62.
The problem to which this invention is directed is to provide opportunities for large-scale production of Nickel-63.
To solve this problem, a method for obtaining a radionuclide, Nickel-63, including the production of enriched Ni-62 Ni target, the irradiation target in the reactor and the subsequent enrichment of the irradiated product of Nickel-63, enriched in Nickel-62 Nickel target, the Nickel-64 does not exceed 2% and the enrichment of the product Nickel-63 isotope Nickel-64 is extracted from the irradiated product.
Large-scale production of Nickel-63 requires more available and cheaper components technology. For irradiation better not to use highly enriched (97-99%) Nickel-62 and Nickel medium enrichment 50-80%. The cost of such target Nickel with significant production is much lower. Irradiation of a large number of cheaper Nickel materials should produce the neutron flow medium level, 2÷5)×1013...2×1014. Such targets can be set for a long exposure in the uranium-graphite reactor (RBMK), industrial reactors, where the radiation is not so expensive as in a nuclear reactor of the type CM-2. This approach will allow to irradiate almost always a large number (hundreds of kg) Nickel targets without disrupting the planned modes of operation of nuclear reactors.
Reducing the requirements to the magnitude of the enrichment of Nickel-62 in the target product, however, should allow the implementation of post-process enrichment of Nickel-63 so that the content of Nickel-63 in the product became prevalent, i.e. at least 50%. The presence in the way of restrictions on the content of Nickel-64 in the target Nickel and Nickel recovery-64 from irradiated product during post-irradiation enrichment are just such conditions.
An example implementation of the method
Below table describes changes in the isotopic occurring at all stages of the process.
Nickel natural isotopic composition in the form of tetrofosmin Nickel - Ni(PF3)4(line 1) sent for isotopic enrichment. The enrichment process carried out so that the Nickel-64 was not more than 2% (line 2). This restriction allows for the enrichment of Nickel up to 50% or more, but the main isotopic impurity due is to be lighter, than Nickel-62 isotopes. Enriched in Nickel-62 tetrofosmin Nickel is transferred to the metal and sent for irradiation in the reactor. After 2 years of exposure in the reactor builds up 6.4% of Nickel-63, and Nickel-64 increases to 1.5% due to the burnout of Nickel-63 (line 3). Irradiated Nickel metal transferred to tetrofosmin Nickel and sent for enrichment. Enrichment of Nickel-63 is carried out in the heavy fraction, and Nickel-64 is extracted from the irradiated material (line 4). It is low maintenance Nickel-64 and allows you to achieve enrichment of Nickel-63 to 50% and more. Tetrofosmin Nickel is transferred to the metal mold and is used, for example, beta-voltaic power sources. In the remaining light fraction (line 5) contains a Nickel-62, the remains of Nickel-63 and no Nickel-64. This product can be re-directed back to the reactor for irradiation.
|Product||Isotopes of Nickel|
|1||the original Nickel to the enrichment of Nickel-62||68,07||-||26,22||1,14||3,63||-||0,93|
|2||the target obtained after enrichment and directed to irradiation||0,1||-||10,0||9,9||79,0||-||1,0|
|3||after 2 years of exposure||0,097||0,002||9,8||to 9.93||72,3||6,4||1,5|
|4||enrichment of Nickel-63 in heavy fraction||0,4||74,9||24,7|
|5||the remaining light fraction||0.104 g||0,002||10,5||10,6||77,1||1,7||0,003|
Receiving target Nickel with restriction on the content of the Nickel-64 allows a significant amount of the target product for large-scale production of Nickel-63, which can be used in stand-alone sources of electrical energy based on the beta voltaic effect, the detectors of explosives and other
The feasibility of technical solutions derived from the research and practice of various methods of isotope separation as uranium and stable isotopes (see, for example,a collection of Isotopes in the USSR", Moscow, Atomizdat, 1980). The reproducibility of the results is determined by highest achieved level of analysis, the isotopic composition of elements known methods of mass spectrometry.
A method of producing a radionuclide Nickel-63, including the production of enriched Ni-62 Ni target, the irradiation target in the reactor and the subsequent enrichment of the irradiated product of Nickel-63, characterized in that in-rich Ni-62 Ni target, the Nickel-64 does not exceed 2% and the enrichment of the product Nickel-63 isotope Nickel-64 is extracted from the irradiated product.
FIELD: radio-chemistry; methods of production of the chromatographic generator of technetium-99m from the irradiated by neutrons molybdenum-98.
SUBSTANCE: the invention is pertaining to the field of the radio-chemistry, in particular, to the methods of production of technetium-99m for medicine. Determine the specific activity of the molybdenum and the sorptive capacity of the used aluminum oxide in molybdate-ions. The mass of the molybdenum necessary for production of the preset activity of the eluate of technetium-99m determine from the ratio:ATc= 0.867·L·m ln (m)/ln(mox·Wi), where:ATc - activity of the eluate of technetium-99m, Ki; L - the specific activity of molybdenum, Ki/g; m - mass of molybdenum, g;mox - the mass of aluminum oxide in the chromatograph column, g; Wi - the sorptive capacity of the used aluminum oxide in molybdate-ions, g/g. After making of corresponding calculations the solution of molybdenum is applied on the aluminum oxide. The technical result of the invention consists in production of the generator with the required activity of technetium-99m at usage of the minimum quantity of molybdenic raw.
EFFECT: the invention ensures production of the generator with the required activity of technetium-99m at usage of the minimum quantity of molybdenic raw.
1 ex, 2 tbl, 1 dwg
FIELD: chemical industry; methods of enrichment and separation of the isotopes of selenium.
SUBSTANCE: the invention is pertaining to the field of separation of the isotopes, in particular, the process of separation of the stable isotopes by the gas centrifugation. In compliance with the method the enrichment of the isotopes of selenium is exercised by the gas centrifugation of the volatile chemical compound of selenium, in the capacity of which they feed to the gas centrifugation the volatile compound of selenium, which does not contain the fluorine atoms, such as hydrogen selenide (H2Se) or selenophene (C4H4Se) or dimethylselenium (Se(CH3)2). The technical result of the invention is the increased purity of the produced isotopic selenium at the expense of exception of the fluorine-containing components at the simultaneous improvement of the process safety.
EFFECT: theinvention ensures the increased purity of the produced isotopic selenium due to exception of the fluorine-containing components at the simultaneous improvement of the process safety.
4 cl, 3 ex, 1 tbl
FIELD: recycling technology for power-generating nuclear materials.
SUBSTANCE: concentration of uranium-235 fissionable isotope is raised above source content to desired value of 2-5 mass percent by direct enrichment in cascade of gas centrifuges. Uranium-235 concentration in cascade dump is 0.1-0.3 mass percent. At the same time uranium isotope mixture having lower concentration of uranium-232 and uranium-236 isotopes than burnt-up source mixture is thinned with hexafluoride. To this end uranium-thinner hexafluoride is introduced to interstage stream of cascade at same or almost same concentration of uranium-235 fissionable isotope. For thinning use is made of hexafluoride of natural mixture of uranium isotope, hexafluoride of uranium isotope mixture separated from burnt-up nuclear fuel, as well as mixture of source uranium isotope burnt-up mixture and hexafluoride of natural mixture of uranium isotopes or hexafluoride of uranium isotope mixture separated from burnt-up nuclear fuel.
EFFECT: ability of producing marketable uranium hexafluoride at minimal quantity of uranium-separating factory facilities used for thinner production.
16 cl, 3 dwg, 3 tbl
FIELD: centrifuges for separation of gaseous and isotopic mixtures, in particular, construction of gas centrifuge units mounted on supporting frames, for example commercial gas centrifuges employed in uranium isotope separation plants or in multiple-unit stands for separation of stable isotopes.
SUBSTANCE: gas centrifuge unit has centrifuges arranged in two rows and fixed on single frame consisting of longitudinal, vertical and transverse beams, said frame being movable in horizontal direction and positioned with its upper transverse beams on supporting overhanging arms of columns and fixed on said overhanging arm by means of flexible member. Flexible member is made in the form of rubber buffer fixed on frame and put onto rod secured in overhanging arm. Buffer is positioned within bushing fixed on vertical beam between upper and lower transverse beams in the vicinity of horizontal plane extending through center of gravity of unit. Alterations in attachment construction and interconnections between members for attachment of units on columns allow effect of earthquake vibrations on centrifuges of unit to be reduced by 1.5-2 times.
EFFECT: increased efficiency in suppressing of earthquake vibrations in construction and reduced effect of earthquake vibrations on centrifuges of unit.
15 cl, 13 dwg
FIELD: atomic industry; methods of purification of the oily waste waters and the phase separation.
SUBSTANCE: the invention is pertaining to the gaseous centrifugal machines for separation of mixtures of gases and isotopes and, in particular, to the design of the aggregates of the gaseous centrifugal machines mounted on the support frames, for example, of the industrial groups of the gaseous centrifugal machines of the works for separation of uranium isotopes or the multi-aggregate stands for separation of the stable isotopes. The aggregate of the gaseous centrifugal machines contains the centrifugal machines arranged in two rows and fixed on common frame with the transversal girders mounted on the supporting cantilever arms of the columns. The transversal girders are additionally rest upon the cantilever arms of the spring-loaded rods. The given design allows to increase the reliability of the gaseous centrifugal machines in the structure of the aggregates arranged in the upper tiers of the configurations at the heightened seismic intensity and the higher numbers of the seismic disturbances.
EFFECT: the invention ensures the increased reliability of the gaseous centrifugal machines in the design of the aggregates located in the upper tiers of the configurations at the heightened seismic intensity and the higher numbers of the seismic disturbances.
5 cl, 3 dwg
FIELD: nuclear fuel technology.
SUBSTANCE: invention relates to nuclear fuel cycle and can be used in manufacturing of nuclear reactor fuels by processing high-enrichment uranium removed from dismantled nuclear ammunition and having elevated content of minor uranium isotopes. Method of invention comprises conversion of high-enrichment arms uranium in its hexafluoride, which is then purified by removing chemical impurities in sorption-desorption cycle on metal fluorides. Isotope composition of high-enrichment uranium is adjusted on condition of restricting level of minor isotope in high-enrichment uranium by their limiting values on a rectangular-stepped cascade of gas centrifuges at ratio of numbers of steps in heavy and light fraction branches of the cascade 1:(8÷26). High-enrichment uranium hexafluoride is then mixed with diluting uranium hexafluoride enriched in uranium-235 isotope above its natural level, which was prepared from commercial natural material. Withdrawn light fraction of high-enrichment uranium cascade is diluted with refuse stream from uranium-diluent manufacture.
EFFECT: reduced irreversible loss of U-235, minimized separation means to manufacture high-enrichment uranium diluent, and reused isolated minor uranium isotopes.
4 cl, 1 dwg, 2 ex
FIELD: nuclear industry; the aggregates of the gaseous centrifugal machines for separation of admixtures of the gases and the isotopic admixtures.
SUBSTANCE: the invention is pertaining to the aggregates of the gaseous centrifugal machines for separation of admixtures of the gases and the isotopic admixtures, in particular, to the design of the aggregates of the gaseous centrifugal machines mounted on the support frames in some floors in height, for example, at the uranium isotopes separation plants or on the multi-aggregate benches for separation of the stable isotopes. The aggregate of the gaseous centrifugal machines contains: the centrifugal machines arranged in the form of two rows and fixed on the common frame with the transversal beams installed on the support consoles of the columns; the frame is supported on the lower ends of the vertical rods, which upper part is mounted on the console. For the supports they used the ball-type washers and bushes mounted with the capability of the horizontal motion in the holes of the consoles. The rods lower ends are mounted on the lower transversal beams, and the rods upper ends are passing into the holes of the upper transversal beam and on them there is the washer, which is pressed to the surface of the beam by the spring. The upper ends of the rods may be installed on the staves arranged on the consoles, and the lower ends of the rods - on the support components fixed on the lower transversal beams. The supporting components are protruding outside the frame dimensions in width and length. The technical result of the invention is reduction of the effect of the seismic disturbances on the gaseous centrifugal machines in 1.5-2 times due to damping of the seismic oscillations by the aggregate design components.
EFFECT: the invention ensures reduction of the effect of the seismic disturbances on the gaseous centrifugal machines in one and a half- two times due to damping of the seismic oscillations by the aggregate design components.
16 cl, 7 dwg
SUBSTANCE: apparatus comprises centrifuges arranged in two rows and connected with the common frame made of longitudinal, vertical, and transverse beams. The frame is mounted for permitting horizontal movement and is secured to the cantilever via a flexible member. The flexible member is made of C-shaped spring whose one end is secured to the cantilever and the other end is secured to the top transverse beam .
EFFECT: improved design and enhanced reliability.
11 cl, 10 dwg
FIELD: recovery of spent nuclear fuel.
SUBSTANCE: proposed method involves enhancement of uranium-235 isotope content in recovered uranium to 2.0-5.0 mass percent while reducing absolute and/or relative concentration of uranium even isotopes. Method includes division of isotope mixture of raw uranium reagent in gas-centrifuge isotope-division cascade and mixing of separated commercial isotope mixture with uranium thinner. Isotope mixture division is effected in two-cascade arrangement. Raw uranium reagent is enriched with uranium-235 fissionable isotope in first single cascade up to content over 90 mass percent. Second single cascade is used for cleaning isotope mixture from uranium-232 and uranium-234 isotopes. Select flow of second cascade enriched with uranium-235 isotope is conveyed as commercial isotope mixture for mixing up with uranium-thinner.
EFFECT: enhanced quality of reducing recovered uranium and minimized uranium-thinner requirement.
12 cl, 1 dwg, 6 tbl
FIELD: gas centrifuges for separation of gas mixtures and isotope mixtures; construction of gas centrifuge units; industrial centrifuges for separation of uranium isotopes or multi-unit stands for separation of stable isotopes.
SUBSTANCE: proposed gas centrifuge unit has centrifuges arranged in two rows and secured on common frame equipped with transversal beams mounted on bearing cantilevers of columns; frame is additionally supported by springs mounted on lower ends of vertical rods whose upper ends are mounted on cantilever. Springs may be mounted on lower transversal beams and may be pressed to them by means of nut and washer. Springs may be also mounted on bearing members secured on lower transversal beams; bearing members may extend beyond clearance limits of frame in width and length. Upper ends of rods may be mounted on plates located on cantilevers. Use of this unit makes it possible to decrease seismic action by 1.5-2 times.
EFFECT: enhanced dampening of seismic oscillations and reduction of seismic action.
8 cl, 4 dwg
FIELD: physics of elementary particles, neutrino, for example.
SUBSTANCE: proposed cascade includes separating steps each of which is connected by inter-step pipe lines for transfer of xenon flow of light fraction of previous step to supply line of next step and for transfer of xenon flow from heavy fraction of subsequent step to supply line of previous step. Cascade is also provided with pipe lines for delivery of gas mixture to supply line of one of steps and discharge of separated flows of xenon light and heavy fractions from cascade. Inter-step pipe lines are provided with coolers over entire length of cascade, at least every 5 steps. Besides that, additional coolers are mounted on pipe lines at outlets of separated flows of xenon light and heavy fractions. Coolers are hollow and have U-shaped or loop-shaped profile at temperature of (-70)-(-78)°C.
EFFECT: increased productivity of each step and cascade as a whole; increased separating capacity; removal of admixtures and water vapor.
4 cl, 1 dwg, 1 tbl
FIELD: designs of the gas centrifugal machines.
SUBSTANCE: the invention presents a gas centrifuge and is dealt with designs of the gas centrifugal machines used for separation of isotopic and gas mixtures, mainly for separation of uranium isotopes. The centrifugal machine contains a rotor with butt covers, a fixed gas-distributing collector installed inside the rotor along its axis of rotation and including a channel for delivery of a stream of feeding into the rotor and an inlet device coupled with it through a flexible pipe used for feeding the rotor. The flexible coupling allows to move the inlet device of feeding in the collector without disassembly of the rotor, that is realized with the help of the demountable hard rods inserted inside the rotor along the collector and fixed on the inlet device of feeding. The offered device allows to perform an accelerated, more reliable and at lower cost optimization of technical characteristics of the centrifugal machine and also exploration of its internal hydraulics.
EFFECT: the invention allows to perform an accelerated, more reliable and with a lower cost optimization of technical characteristics of the centrifugal machine, and exploration of its internal hydraulics.
FIELD: chemical industry; nuclear technology; methods of production of a high-enriched isotope - silicon-28.
SUBSTANCE: the invention is pertaining to the field of chemical industry and nuclear technology, in particular, to the methods of production of a high-enriched isotope - silicon-28. The initial trichlorosilane passes through a separating cascade of gaseous whizzers. In the routes of the last cut of the cascade stages mount devices for realization of reaction of the isotopic exchange, which contain a solid accelerator with a developed surface, for example, with a fibrillar sorption-active substance filled with an activated charcoal. The devices may be heated up to increase effectiveness of operation. Usage of these devices allows to bring trichlorosilane in the stages of the cascade to equilibrium. The target isotope - silicon-28 is separated from the routes of the light fraction. The invention allows to produce a high-enriched (more than 99.9 %) isotope - silicon-28 with high efficiency and a degree of extraction.
EFFECT: the invention ensures production of a high-enriched isotope - silicon-28 with a high efficiency and a degree of extraction.
2 cl, 2 tbl