RU2760902C1 - Uranium-based alloy (options) - Google Patents

Abstract

FIELD: nuclear technology.SUBSTANCE: invention relates to nuclear technology and can be used as nuclear fuel in manufacture of fuel elements for thermal reactors of WWER type. The uranium-based alloy contains, by wt %: silicon 2.0-7.0, aluminum 0.1-2.0, at least one element selected from the group: carbon 0.15-2.0, oxygen 0.15-2.0, nitrogen 0.15-1.0, and uranium - the rest. The uranium-based alloy may additionally contain at least one of the elements selected from group: molybdenum 0.15-5.0, niobium 0.15-2.0, zirconium 0.15-2.0, titanium 0.15-2.0, tin 0.1-2.0, chromium 0.1-2.0.EFFECT: production of a high-density uranium-based alloy with high uranium capacity while maintaining thermodynamic stability, high liquidus temperature and high radiation resistance is ensured.6 cl, 6 dwg, 1 tbl, 11 ex

Description

The invention relates to nuclear technology and can be used as nuclear fuel in the manufacture of fuel elements (fuel elements) for commercial thermal reactors of the VVER type.

All over the world, within the framework of an international program for the development of tolerant fuels, a more uranium-intensive and heat-conducting metal fuel than uranium dioxide is being developed, which makes it possible to reduce the operating temperatures of the fuel to 500-600 ° C, in particular uranium disilicide and uranium-molybdenum alloys [H.J. Chichester, R.D. Mariani, S.L. Hayes, J.R. Kennedy, A.E. Wright, Y.S. Kim, "Advanced metallic fuel for ultrahigh bum-up: irradiation tests in ATR," Embedded Topical on Nuclear Fuel and Structural Material, American Nuclear Society (2012) P 1349-1351].

Nuclear fuel made of uranium disilicide (U3Si2) has a higher uranium content (17% more than that of uranium dioxide), which also makes it possible to increase the conversion rate of nuclear fuel, reduce its enrichment, extend the fuel rod campaign and increase the ICUF (installed capacity utilization factor), which ultimately have a positive impact on the economy of the fuel cycle. In addition, silicon, in comparison with molybdenum in uranium-molybdenum fuel, has a smaller thermal neutron capture cross-section, which improves the physics of the reactor.

In addition, within the framework of the program for the development of tolerant fuel, it is proposed to use claddings made of stainless steels that are more resistant to the vapor-zirconium reaction, having a significantly greater capture of thermal neutrons than claddings made of zirconium alloys [S.J. Zinkle, K.A. Terrani, J.C. Gehin, L.J. Ott, L.L. Snead, Accident tolerant fuels for LWRs: A perspective, Journal of Nuclear Materials 448 (2014). P. 374-379]. In order not to exceed the standardized limitation of 5% uranium-235 enrichment at the manufacturing plants, the use of more uranium-intensive fuel is also required in this case.

However, uranium disilicide has disadvantages that restrain its use in VVER-type reactors as a tolerant fuel. This is a relatively large swelling, low radiation resistance, low corrosion resistance and insufficiently high uranium content (11.3 g / cm ³ ), only 17% more than that of uranium dioxide. In addition, because of its large swelling under irradiation in uranium disilicide pellets, it is necessary to use an axial hole to compensate for the swelling, which further reduces the uranium content in the fuel element.

Previously, the use of a denser uranium silicide (U ₃ Si) with a lower silicon content and a higher uranium content as fuel for a CANDU-type reactor was also considered [SJ Zinkle, K.A. Terrani, JC Gehin, LJ Ott, LL Snead, Accident tolerant fuels for LWRs: A perspective, Journal of Nuclear Materials 448 (2014). P. 374-379]. However, due to its low radiation resistance and corrosion resistance in water, it has not found application, despite its higher density and thermal conductivity than that of uranium dioxide. In addition, the gain in increasing the uranium capacity compared to uranium disilicide led to the loss of the thermodynamic stability of the alloy and, as a consequence, the degradation of its properties (corrosion and radiation resistance).

Known patents [GB 908941A IPC G21C 3/62 publ. 10.24.1962, US 3567581A IPC G21C 3/30 publ. 03/02/1971, CA664803A publ. 06/11/1963] for uranium alloys containing 2-8% of the mass. silicon.

However, in reality, due to non-equilibrium crystallization, the alloys always contain the alpha uranium phase, which is formed at 935 ° C during the crystallization of the α + U ₃ Si ₂ eutectic.

The alpha uranium phase has catastrophically low radiation and corrosive properties and its even negligible presence in the alloy structure causes the destruction of the fuel during operation in the reactor. Therefore, for the formation of a more radiation-resistant uranium silicide, it is necessary to carry out long-term annealing of alloys in vacuum at 800-850 ° C for 100 hours. However, this phase, which also contains 3.5-3.8% silicon and has a high uranium content (14.3 g / cm ³ instead of 11.3 g / cm ³ for uranium disilicide), has low corrosion resistance in water and swells strongly upon irradiation. in the reactor. The use of alloys based on uranium disilicide (7-8% silicon) significantly reduces their uranium content.

Alloys based on the uranium-silicon double system also have a relatively low liquidus temperature (1050-1650 ° C), which determines the stability of the fuel shape in emergencies such as LOCA (Loss Off Coolant Accident). The radiation and corrosion resistance of these alloys, belonging to the group of metal alloys, is also low.

Known patent [US 3717454A IPC C22C 43/00, publ. 02/20/1973] on an alloy of uranium containing 3.5-3.7% of the mass. silicon and 0.2-1.5% of the mass. aluminum. Aluminum is added to the alloy to facilitate the stabilization of the uranium silicide during prolonged annealing and to minimize the alpha uranium phase. Aluminum in an amount of up to 0.5% can dissolve in uranium silicide, which contributes to its thermodynamic stability.

However, the corrosion resistance of these alloys in water was found to be low due to microinclusions of alpha uranium. In addition, all the disadvantages inherent in uranium silicide remained - low radiation resistance (large swelling), low liquidus temperature and the need for a long (up to 100 hours) stabilization annealing.

The closest analogue to the claimed is the patent [US 4023992, IPC C22C 43/00, publ. 05/17/1977] on an alloy of uranium containing 3.2-3.7% of the mass. silicon and 0.8-3.0% of the mass. aluminum. Due to the high content of aluminum, the structure of the alloy after annealing is predominantly the δ-phase of uranium, with precipitates of the phases UAl ₂ and U ₃ Si ₂ .

However, as the authors of the patent themselves note, the high content of aluminum reduces both the uranium capacity of the alloy (the uranium capacity of the UAl ₂ phase is only 6.9 g / cm ³ ) and the liquidus temperature, in comparison with the double uranium-silicon alloy, by almost 200 ° C. , which reduces the resistance of the fuel to emergency situations. In addition, although intermetallic phases partially improve the radiation resistance of the alloy, it remains insufficient for the use of this fuel in VVER-type reactors instead of ceramic fuel made of uranium dioxide, since the radiation resistance of ceramics is significantly superior to intermetallic compounds. In addition, the volume fraction of intermetallic phases in the alloy is small (1-10%).

Despite the increased aluminum content, after smelting such an alloy, heat treatment is still required for 72 hours at 800-850 ° C for the complete disappearance of the α-phase of uranium. In addition, the predominantly δ-phase U ₃ Si formed after heat treatment also has a low radiation resistance inherent to uranium silicide, and is also insufficient for its use in VVER-type reactors instead of ceramic fuel made of uranium dioxide.

Thus, the analysis of known uranium-silicon alloys used as fuel in nuclear reactors showed that currently there are no alloys with thermodynamic stability while maintaining high uranium capacity, high radiation resistance (low swelling) and high liquidus temperature.

The problem to be solved by the present invention is to obtain a high-density alloy based on uranium, with a multiphase cermet structure, having a high uranium capacity while maintaining thermodynamic stability, a higher liquidus temperature and a higher radiation resistance (less tendency to swelling).

The technical result of the proposed invention according to the first and second options is to obtain a high-density alloy based on uranium with a high uranium content while maintaining thermodynamic stability, a higher liquidus temperature and a higher radiation resistance.

The technical result according to the first embodiment is achieved in that the uranium-based alloy contains silicon and aluminum U-Si-Al, and it additionally contains at least one element X selected from the group containing carbon, oxygen, nitrogen in the following ratio components,% wt .:

Silicon 2.0-7.0 Aluminum 0.1-2.0

X - at least one of the elements in% wt., Selected from the group:

Carbon 0.15-2.0 Oxygen 0.15-2.0 Nitrogen 0.15-1.0 Uranus Rest

The alloy is obtained by melting.

The alloy was obtained by melting, followed by annealing.

The technical result according to the second embodiment is achieved in that the uranium-based alloy contains silicon and aluminum U-Si-Al, and it additionally contains at least one element X selected from the group containing carbon, oxygen, nitrogen, and additionally contains , at least one metal Y, selected from the group containing molybdenum, niobium, zirconium, titanium, tin, chromium, in the following ratio of components, wt%:

Silicon 2.0-7.0 Aluminum 0.1-2.0

where X is at least one of the elements in wt%, selected from the group:

Carbon 0.15-2.0 Oxygen 0.15-2.0 Nitrogen 0.15-1.0

where Y is at least one of the metals in wt%, selected from the group:

Molybdenum 0.15-5.0 Niobium 0.15-2.0 Zirconium 0.15-2.0 Titanium 0.15-2.0 Tin 0.1-2.0 Chromium 0.1-2.0 Uranus Rest

The alloy is obtained by melting.

The alloy was obtained by melting, followed by annealing.

To solve the problem, according to the first option, it is proposed to introduce at least one element X selected from the group containing carbon, oxygen, nitrogen into the composition of uranium-silicon alloys that form ceramic compounds U (C, N, O, Si), UO ₂ , UC, UN, etc. These compounds have high radiation resistance and high melting points. As a result, the resulting complex structure of an alloy of uranium silicides is strengthened by ceramic phases. A composite-type structure is formed, which has improved properties in comparison with the initial uranium silicides.

Ceramic and intermetallic phases have significantly better radiation resistance and less swelling due to stronger interatomic bonds.

The presence of ceramic refractory compounds in the alloy structure significantly increases the liquidus temperature of the alloy, which determines the stability of the fuel during LOCA accidents in VVER reactors.

The content of the elements forming the ceramic phases, less than 0.15% (carbon, oxygen, nitrogen), gives an insignificant effect of improving thermodynamic stability, increasing the liquidus temperature and radiation resistance.

The content of carbon and oxygen over 2%, and nitrogen over 1% reduces the uranium content of alloys, and also leads to a decrease in the ductility of the alloy due to the brittleness of the ceramic phases. This can lead to technological difficulties in the manufacture of alloys by casting, difficulties in the machining of alloys and the manufacture of fuel pellets, as well as obtaining the required size of alloy granules by centrifugal atomization.

Another feature of these ceramic refractory compounds is that they bind free uranium during crystallization, thereby reducing the amount of alpha uranium phase after melting and increasing thermodynamic stability, liquidus temperature and radiation resistance.

According to the second option, in addition to the introduction of at least one element X selected from the group containing carbon, oxygen, nitrogen, at least one element Y selected from the group containing molybdenum, niobium, zirconium can be introduced into the alloy. titanium, as a gamma stabilizing additive for additional transformation of clusters of the alpha uranium phase into a more radiation-resistant cubic gamma phase. Thus, gamma stabilizing additives help to maintain the thermodynamic stability of the alloy. In addition, the time of the subsequent annealing to the δ-phase (U ₃ Si) is significantly reduced, or it is even possible to completely avoid this technological operation.

Other alloying elements Y - chromium and tin, in small amounts, as an addition to the main alloying elements, along with aluminum, stabilize the 8-phase, and also form additional intermetallic phases that improve radiation resistance.

Additions of gamma stabilizing metals less than 0.15% (Mo, Nb, Zr, Ti), which bind excess precipitates of the alpha uranium phase, practically do not affect the stabilization of the gamma phase, but more than 5.0% for Mo and more than 2.0% for Nb , Zr, Ti reduce the uranium content of alloys.

The content of tin, chromium is less than 0.1%, forming additional intermetallic phases in the alloy, gives an insignificant effect.

The content of tin, chromium over 2% reduces the uranium content of the alloys.

FIG. 1 shows the microstructure of the alloy U-2.0Si-2.0Al-0.15C-0.15O-5.0Mo-2.0Nb after melting according to example 4.

FIG. 2 shows the microstructure of the alloy U-3.1Si-0.3Al-0.3C-0.3O-0.15N-0.7Zr-0.5Ti-2.0Sn-2.0Cr after melting according to example 5.

FIG. 3 shows the microstructure of the alloy U-3.6Si-0.4Al-0.15C-0.4O-1, 0N-1.0Mo after melting according to example 6.

FIG. 4 shows the microstructure of the U-7.0Si-0.1Al-0.15C-0.15O-0.3Mo-0.16Nb-0.1Cr alloy after melting according to example 7.

FIG. 5 shows the microstructure of the alloy U-3.2Si-0.3Al-2.0C-0.3O-0.15Zr-0.15Ti-1.0Sn-1.0Cr after melting according to example 8.

FIG. 6 shows the microstructure of the U-2.7Si-0.1Al-0.15C-2.0O-2.0Zr-0.15Ti alloy after annealing according to example 9.

Examples of specific execution.

Example 1. Alloy composition (in wt.%)

Silicon 7.0 Aluminum 0.1 Carbon 0.15 Oxygen 0.15 Nitrogen 0.15 Uranus Rest

was made by arc melting method.

Melting was carried out in a small arc furnace of the MEPI-9 brand in an argon atmosphere in a water-cooled copper mold, with a non-consumable tungsten electrode with multiple remelting (4-5 remelts).

For the charge, the starting materials were used - metallic uranium, silicon and aluminum in the form of pieces, carbon in the form of graphite powder. Oxygen was introduced in the form of uranium dioxide granules. Nitrogen was introduced into the furnace atmosphere and absorbed by the melt.

After melting, the ingots were cut for metallographic studies.

After melting, annealing to the δ-phase was carried out at 810 ° C for 24 hours in a "CYD" furnace in a vacuum of 1⋅10 ^-5 mm Hg. Art.

The microstructure of the alloy was investigated both in the as-cast state and after annealing to the δ-phase using optical and electron microscopes.

The liquidus temperature of the alloy was determined by differential thermal analysis (DTA) at heating and cooling rates of 20 deg / min.

X-ray phase analysis was carried out on a general-purpose DRON-3 diffractometer using monochromatic CuKp radiation with a wavelength of 0.1393 nm, by continuous scanning at a speed of 1 deg / min.

The main structural components in the alloy are U ₃ Si ₂ and traces of U (O, C, N). The liquidus temperature of the alloy is 1810 ° C.

After annealing, the structure of the alloy remains practically unchanged; small traces of the U ₃ Si phase appear.

The rest of the alloy parameters are given in the table.

Example 2. Alloy composition (in wt.%)

Silicon 2.0 Aluminum 0.1 Carbon 2.0 Oxygen 2.0 Nitrogen 0.15 Uranus Rest

was made by induction melting.

Induction melting was carried out in a vacuum of 1⋅10 ^-3 mm Hg. Art. High-density ARV graphite was used as the material for the melting and foundry equipment. For the charge, the starting materials were used - metallic uranium, silicon and aluminum in the form of pieces, carbon in the form of graphite powder. Oxygen was introduced in the form of uranium dioxide granules. Nitrogen was introduced into the furnace atmosphere and absorbed by the melt.

During the heats, the temperature of the melt was controlled by an immersion thermocouple. To prevent the interaction of the melt with the material of the melting and casting equipment, a protective coating based on zirconium oxide was applied to its working surface.

The melt temperature when pouring the metal into the mold was 1710 ° C. Temperature control was carried out using a tungsten-rhodium thermocouple. The melt was poured into a graphite mold. Ingots of finished alloys were rods with a diameter of 31 to 32 mm and a length of 200 to 250 mm. The weight of the ingots was about 2 kg. After melting, annealing to the δ-phase was carried out at 850 ° C for 10 hours in a "CYD" furnace in a vacuum of 1⋅10 ^-5 mm Hg. Art.

The studies of the alloy were carried out according to the method described in example 1.

The main structural components in the alloy are U ₃ Si, U (C, O), UO ₂ . The liquidus temperature of the alloy is 1630 ° C.

After annealing, the structure of the alloy did not change.

The rest of the alloy parameters are given in the table.

Example 3. Alloy composition (in wt.%)

Silicon 2.0 Aluminum 2.0 Carbon 0.15 Oxygen 0.15 Nitrogen 1.0 Uranus Rest

was made by induction melting (see example 2).

The melt temperature when pouring the metal into the mold was 1660 ° C.

The studies were carried out according to the method described in example 1.

The main structural components in the alloy are U ₃ Si, U (C, O, N, Si), UAl ₂ . The liquidus temperature of the alloy is 1580 ° C.

After melting, annealing to the δ-phase was carried out. After annealing, the structure of the alloy remained practically unchanged. Small traces of the UN phase appeared.

The rest of the alloy parameters are given in the table.

Example 4. Alloy composition (in wt.%)

Silicon 2.0 Aluminum 2.0 Carbon 0.15 Oxygen 0.15 Niobium 2.0 Molybdenum 5.0 Uranus Rest

was made by induction melting (see example 2).

For the charge, the starting materials were used - metallic uranium, silicon and aluminum in the form of pieces, carbon in the form of graphite powder, molybdenum and niobium in the form of plates. Oxygen was introduced in the form of uranium dioxide granules.

The melt temperature when pouring the metal into the mold was 1550 ° C. After melting, annealing to the δ-phase was carried out at 850 ° C for 10 hours in a "CYD" furnace in a vacuum of 1⋅10 ^-5 mm Hg. Art.

FIG. 1 shows the microstructure of the alloy after melting.

The studies of the alloy were carried out according to the method described in example 1.

The main structural components in the alloy are U ₃ Si, U (O, C, Si), as well as UAl ₂ , U ₃ Si ₂ and traces of γ-U. The liquidus temperature of the alloy is 1470 ° C.

After annealing, the structure of the alloy remained practically unchanged. There was a slight increase in the U ₃ Si and U (O, C, Si) phases and a decrease in the U ₃ Si ₂ phase.

The rest of the alloy parameters are given in the table.

Example 5. Alloy composition (in wt.%)

Silicon 3.1 Aluminum 0.3 Carbon 0.15 Oxygen 0.3 Nitrogen 0.15 Zirconium 0.3 Titanium 0.15 Tin 2.0 Chromium 2.0 Uranus Rest

was made by induction melting (see example 2).

For the charge, the starting materials were used - metallic uranium, silicon, aluminum, zirconium, tin and chromium in the form of pieces, carbon in the form of graphite powder, titanium in the form of plates. Oxygen was introduced in the form of uranium dioxide granules. Nitrogen was introduced into the furnace atmosphere and absorbed by the melt.

The melt temperature when pouring the metal into the mold was 1610 ° C. After melting, annealing to the δ-phase was carried out at 810 ° C for 24 hours in a "CYD" furnace in a vacuum of 1⋅10 ^-5 mm Hg. Art.

The studies were carried out according to the method described in example 1.

FIG. 2 shows the microstructure of the alloy after melting. The main structural components in the alloy are U ₃ Si, U (O, C, N, Si), U ₃ Si ₂ , U ₅ Sn ₄ and traces of γ-U. The liquidus temperature of the alloy is 1530 ° C.

After annealing, the structure of the alloy remained practically unchanged. There was a slight increase in the U ₃ Si and U (O, C, N, Si) phases and the disappearance of traces of the γ-U phase.

The rest of the alloy parameters are given in the table.

Example 6. Alloy composition (in wt.%)

Silicon 3.6 Aluminum 0.2 Carbon 0.15 Oxygen 0.2 Nitrogen 1.0 Molybdenum 0.3 Uranus Rest

was made by arc melting (see example 1).

For the charge, the starting materials were used - metallic uranium, silicon and aluminum in the form of pieces, carbon in the form of graphite powder, and molybdenum in the form of plates. Oxygen was introduced in the form of uranium dioxide granules. Nitrogen was introduced into the furnace atmosphere and absorbed by the melt.

After melting, the ingots were cut for metallographic studies.

After melting, annealing to the δ-phase was carried out at 810 ° C for 24 hours in a "CYD" furnace in a vacuum of 1⋅10 ^-5 mm Hg. Art.

The studies were carried out according to the method described in example 1.

FIG. 3 shows the microstructure of the alloy after melting. The main structural components in the alloy are U ₃ Si, U (N, O, C), U ₃ Si ₂ . The liquidus temperature of the alloy is 1720 ° C.

After annealing, the structure of the alloy remained practically unchanged. There was a slight increase in the U (N, O, C) phase and a decrease in the U ₃ Si ₂ phase.

The rest of the alloy parameters are given in the table.

Example 7. Alloy composition (in wt.%)

Silicon 7.0 Aluminum 0.1 Carbon 0.15 Oxygen 0.15 Molybdenum 0.3 Niobium 0.16 Chromium 0.1 Uranus Rest

was made by arc melting (see example 1).

For the charge, the starting materials were used - metallic uranium, silicon, aluminum and chromium in the form of pieces, carbon in the form of graphite powder, molybdenum and niobium in the form of plates. Oxygen was introduced in the form of uranium dioxide granules.

The studies were carried out according to the method described in example 1.

FIG. 4 shows the microstructure of the alloy after melting. The main structural components in the alloy are U ₃ Si ₂ , U (O, C, Si). The liquidus temperature of the alloy is 1810 ° C. After melting, annealing to the δ-phase was not performed.

The rest of the alloy parameters are given in the table.

Example 8. Alloy composition (in wt.%)

Silicon 3.2 Aluminum 0.3 Carbon 2.0 Oxygen 0.3 Zirconium 0.15 Titanium 0.15 Tin 0.5 Chromium 0.1 Uranus Rest

was made by arc melting (see example 1).

For the charge, the starting materials were used - metallic uranium, silicon, aluminum, zirconium, tin and chromium in the form of pieces, carbon in the form of graphite powder, titanium in the form of plates. Oxygen was introduced in the form of uranium dioxide granules.

The studies were carried out according to the method described in example 1.

FIG. 5 shows the microstructure of the alloy after melting. The main structural components in the alloy are U ₃ Si, U (C, O), U ₃ Si ₂ , and U ₅ Sn ₄ . The liquidus temperature of the alloy is 1690 ° C. After melting, annealing to the δ-phase was not performed.

The rest of the alloy parameters are given in the table.

Example 9. Alloy composition (in wt.%)

Silicon 2.7 Aluminum 0.1 Carbon 0.15 Oxygen 2.0 Zirconium 2.0 Titanium 0.15 Uranus Rest

was made by arc melting (see example 1).

For the charge, the starting materials were used - metallic uranium, silicon, aluminum and zirconium in the form of pieces, carbon in the form of graphite powder, titanium in the form of plates. Oxygen was introduced in the form of uranium dioxide granules.

The studies were carried out according to the method described in example 1.

After melting, annealing to the δ-phase was carried out at 850 ° C for 10 hours in a "CYD" furnace in a vacuum of 1⋅10 ^-5 mm Hg. Art.

FIG. 6 shows the microstructure of the alloy after melting. The main structural components in the alloy are U ₃ Si, UO ₂ , as well as U ₃ Si ₂ and traces of α-U. The liquidus temperature of the alloy is 1740 ° C.

After annealing, the traces of the α-U phase turned into the γ-U phase.

The rest of the alloy parameters are given in the table.

Example 10. Alloy composition (in wt.%)

Silicon 2.0 Aluminum 0.1 Carbon 0.15 Oxygen 0.15 Nitrogen 0.15 Molybdenum 0.15 Niobium 2.0 Zirconium 2.0 Titanium 2.0 Tin 0.1 Chromium 2.0 Uranus Rest

was made by induction melting (see example 2).

For the charge, the starting materials were used - metallic uranium, silicon, aluminum, zirconium, tin and chromium in the form of pieces, carbon in the form of graphite powder, molybdenum, niobium and titanium in the form of plates. Oxygen was introduced in the form of uranium dioxide granules. Nitrogen was introduced into the furnace atmosphere and absorbed by the melt.

The melt temperature when pouring the metal into the mold was 1670 ° C.

The studies were carried out according to the method described in example 1.

The main structural components in the alloy are U ₃ Si, U (C, O, N.Si), traces of γ-U. The liquidus temperature of the alloy is 1590 ° C.

After melting, annealing to the δ-phase was carried out. After annealing, the content of the γ-U phase increases in the alloy structure.

The rest of the alloy parameters are given in the table.

Example 11. Alloy composition (in wt.%)

Silicon 2.0 Aluminum 0.3 Carbon 0.15 Oxygen 0.15 Nitrogen 0.15 Molybdenum 5.0 Niobium 0.15 Zirconium 0.15 Titanium 0.15 Tin 2.0 Chromium 0.1 Uranus Rest

was made by induction melting (see example 2).

For the charge, the starting materials were used - metallic uranium, silicon, aluminum, zirconium, tin and chromium in the form of pieces, carbon in the form of graphite powder, molybdenum, niobium and titanium in the form of plates. Oxygen was introduced both in the form of uranium dioxide granules and in the form of molybdenum oxide (MoO ₃ ) having a low melting point. Nitrogen was introduced into the furnace atmosphere and absorbed by the melt.

The melt temperature when pouring the metal into the mold was 1640 ° C.

The studies were carried out according to the method described in example 1.

The main structural components in the alloy are U ₃ Si, U (C, O, N, Si), γ-U, traces of U ₅ Sn ₄ and U ₃ Si ₂ . The liquidus temperature of the alloy is 1560 ° C.

After melting, annealing to the δ-phase was carried out. After annealing, the U ₃ Si ₂ phase disappears in the alloy structure.

The rest of the alloy parameters are given in the table.

The table shows the main properties of uranium-based alloys (prototype) in comparison with the claimed alloyed alloys based on uranium in examples 1-11

Thus, the claimed high-density alloy based on uranium (options), containing silicon and aluminum, having a multiphase cermet structure, consisting of a mixture of uranium disilicide, ceramic phases, uranium silicide and (or) intermetallic phases, provides the achievement of the technical result - obtaining an alloy with high uranium capacity while maintaining thermodynamic stability, higher liquidus temperature and higher radiation resistance.

Claims (14)

1. Alloy based on uranium containing silicon and aluminum, characterized in that it additionally contains at least one element selected from the group containing carbon, oxygen, nitrogen, in the following ratio of components, wt%: Silicon 2.0-7.0 Aluminum 0.1-2.0 at least one of the elements selected from the group: Carbon 0.15-2.0 Oxygen 0.15-2.0 Nitrogen 0.15-1.0 Uranus Rest 2. The uranium-based alloy according to claim 1, characterized in that it is obtained by melting. 3. The uranium-based alloy according to claim 1, characterized in that it is obtained by melting followed by annealing. 4. Alloy based on uranium containing silicon and aluminum, characterized in that it additionally contains at least one element selected from the group containing carbon, oxygen, nitrogen, and further contains at least one metal selected from the group containing molybdenum, niobium, zirconium, titanium, tin, chromium, with the following ratio of components, wt%: Silicon 2.0-7.0 Aluminum 0.1-2.0 at least one of the elements selected from the group: Carbon 0.15-2.0 Oxygen 0.15-2.0 Nitrogen 0.15-1.0 at least one metal selected from the group: Molybdenum 0.15-5.0 Niobium 0.15-2.0 Zirconium 0.15-2.0 Titanium 0.15-2.0 Tin 0.1-2.0 Chromium 0.1-2.0 Uranus Rest 5. The uranium-based alloy according to claim 4, characterized in that it is obtained by melting. 6. The uranium-based alloy according to claim 4, characterized in that it is obtained by melting followed by annealing.

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