RU2812963C1 - Ceramic blanket module for fusion reactor - Google Patents

Abstract

FIELD: thermonuclear technology.

SUBSTANCE: ceramic module of a thermonuclear reactor blanket used for reproduction of the hydrogen isotope - tritium. The blanket module consists of first wall [1] made of a refractory material, behind which lithium circulates, irradiated by a neutron flux, and tritium forms lithium hydride, reacting with the surrounding lithium. Thermoregulation is carried out by plate made of temperature-conducting material [2]. A mixture of lithium and lithium hydride, entering storage tank [3], evaporates into the cavity above the storage tank, through separator [4], where it reacts with porous ceramics [5]. Moreover, the ceramics consists of a globular structure, which makes it possible to use the available space to find lithium hydride, and during the reaction, tritium and lithium orthosilicate are formed, which is subsequently irradiated with neutrons to additionally produce tritium.

EFFECT: increased tritium production, as well as possibility of cyclic use of lithium with double use of tritium-regenerating ceramics.

1 cl, 2 dwg, 2 tbl

Description

Field of technology

The scope of application of the proposed technical solution is thermonuclear technology. The device is necessary for the reproduction of the hydrogen isotope - tritium, which is used to operate thermonuclear research power plants.

State of the art

1. The technical solution is known [LITHIUM IN THE ENERGY THERMONUCLEAR REACTOR I.E. Lublinsky (FSUE "Red Star") 2006], the essence of which is as follows:

To practically implement the possibility of using liquid lithium as a material in contact with plasma, it is proposed to use lithium capillary-porous structures - CPS. The supply of liquid metal to the surface in contact with plasma occurs through channels penetrating the CPS. Its characteristics (variable porosity, anisotropy of permeability, geometry of the working surface, etc.) can be adjusted within wide limits by changing the manufacturing technology. The design of the CPS can provide sufficient pressure of the working fluid in the make-up system due to capillary pressure forces. Such a system is self-restraining and self-regulating, since the pressure distribution of the working fluid in the CV joint acutely reacts to local changes in the thermal load on its surface.

The disadvantage of this technical solution is the labor-intensive production of molybdenum-tungsten wires with a diameter of 100 microns, the low wear resistance of the structure, which requires periodic replacement of burnt-out parts of the blanket. There is a risk of parts of the wire structure getting into the area of the thermonuclear reactor chamber, which significantly affects plasma confinement, also, as the authors themselves note (variable porosity, anisotropy of permeability, etc.), negatively affect the operational characteristics of the presented technical solution, also in the process of tritium production , it interacts with lithium - lithium hydride.

2. Another technical solution is also known [RESEARCH OF THE PROPERTIES OF LITHIUM-CONTAINING CERAMICS PROPOSED FOR USE IN BLANKETS OF RUSSIAN THERMONUCLEAR REACTORS AND ASSESSMENT OF THEIR INFLUENCE ON TECHNOLOGICAL SYSTEMS OF V.K. REACTORS Kapyshev, April 17, 2003], the essence of which is as follows.

One of the most promising options for a tritium breeding zone (TBR) blanket is a helium-cooled lithium-containing ceramic breeder using beryllium as a neutron multiplier.

A technology has been developed for the production of tablets from lithium orthosilicate, metasilicate and aluminate with reproducible geometric parameters and physical properties. Reactor irradiation showed a higher radiation resistance of aluminate and the possibility of using lithium orthosilicate in reactor blankets without changing their service properties ~ 3% for lithium.

The disadvantage of this technical solution is that the production of ceramic lithium-containing tablets is labor-intensive; the presented technological scheme of synthesis requires high manufacturing precision; during operation, it is necessary to replace burnt-out ceramics, which complicates the operation of the blanket.

3. The closest to the claimed technical solution is [patent RU2649854, IPC G21B 1/13 dated September 15, 2017], the essence of which is as follows:

The invention relates to the field of thermonuclear technology, in particular to blankets of hybrid thermonuclear reactors. The blanket module of a hybrid thermonuclear reactor with liquid metal coolant contains fuel assemblies with fuel elements. The fuel element fuel is made from minor actinide oxide. Fuel assemblies are made of rectangular cross-section. The technical result is an increase in the multiplying properties of the nuclear zone of the blanket module of a thermonuclear reactor. Secondary neutrons from the nuclear zone, entering the breeder zone with a ceramic breeder, are slowed down and absorbed by lithium nuclei, which leads to the production of tritium.

The disadvantage of this technical solution is the uneven reproduction of tritium, the burning of lithium from the ceramic breeder occurs unevenly, and the resulting anisotropy of properties reduces the performance characteristics of the invention.

Disclosure of the Invention

The objective of the proposed technical solution is to create a tritium-breeding module of a thermonuclear reactor (TNR), technologically advanced in production, operation and maintenance, the use of which is possible both separately from the working chamber and together, through a blanket.

The manufacturability of this method of producing tritium is achieved by creating porous ceramics based on silica. Finely dispersed SiO ₂ globules have a melting point of about 1400°C, which contributes to long-term operation

Silica globules form a single isotropic structure with equal spacing, both between nanostructures and between their layers, which makes it possible to use the available space to find lithium hydride.

In the process of work, the need arose to carry out high-quality chemical calculations to determine the possibility of the proposed reactions occurring, for this we will use the laws of thermodynamics

I) Let us make sure that the reaction of interaction of lithium vapor with silica globules (formula (1)) can occur.

(1)

where Li is the residual lithium pairs supplied into the pores between the globules

SiO ₂ - silica.

Li ₂ O and Si are lithium oxide and silicon putative products.

For calculations, we use the thermodynamic data of Table 1 [Haynes,, W. M. CRC Handbook of Chemistry and Physics 97th Edition / W. M. Haynes,. - Boca Raton: CRC Press, 2016. - 2643 pp.]

Table 1

Substance
(Section in the book) ∆ H ⁰ ₂₉₈ kJ/mol ∆ G ⁰ ₂₉₈ kJ/mol S ⁰ ₂₉₈ J/mol⋅K C ⁰ _p J/mol⋅K H ₂ gas (5-22) 0 0 130.52 28.8 Li liquid (5-25) 0 0 29.1 24.9 Si solid (5-35) 0 0 18.72 20 LiH liquid (5-25) -90.67 -68.7 20.6 27.9 Li ₂ SiO ₃ solid (5-25) -1648 -1557.2 79.8 99.1 SiO ₂ solid (5-35) -910.7 -856.3 42.26 44.4

Let's calculate the Gibbs energy and verify the possibility of reaction (1)

1) Calculate the thermal effect

(2)

Where - stoichiometric coefficients of reagents

(3)

Let's substitute the data from Table 1

(3.1)

2) Calculate entropy

(4)

Where - stoichiometric coefficients of reagents

(5)

Let's substitute the data from Table 1

(5.1)

3) Let's calculate the Gibbs energy at T= 1000 K

(6)

(7)

∆ G ⁰ ₂₉₈ <0, the process at T =1000 K proceeds in the forward direction

II) When lithium is irradiated with neutrons during thermonuclear fusion or a neutron multiplication reaction in a breeder, the hydrogen isotope tritium (formula (12)) is formed.

(8)

Then, according to formula (8), the resulting hydrogen will interact with the lithium surrounding it (formula (9).

(9)

1) Calculate the thermal effect

(10)

Let's substitute the data from Table 1

(10.1)

2) Calculate entropy

(eleven)

Let's substitute the data from Table 1

(11.1)

3) Let's calculate the Gibbs energy at T = 1000 K according to the Temkin-Schwartzman method, for a more accurate calculation result compared to (10) Referring to [Quick reference book of physical and chemical quantities. Tenth edition, corrected and supplemented. / Ed. A. A. Ravdel and A. M. Ponomareva - St. Petersburg: “Ivan Fedorov”, 2003. P.76, ill. ISBN 5-8194-0071-2]

The following coefficients were taken for calculation at T = 1000 K.

4) Let us find the standard heat capacities of substances in the form of formula (13).

Wherea, b, c, c ^' - coefficients characteristic of a given substance and calculated from experimental data for a given substance. [Zhigach, A.F. Chemistry of hydrides / A.F. Zhigach, D.S. Stasinevich. - Leningrad: Chemistry, 1969. P.52-53.]

5) Then we will find the dependence of ∆C _p on temperature according to formula (17)

6) Find ∆ a , ∆ b , ∆ c , ∆ c ^' according to formulas (18.1)-(18.4)

7) Let's calculate the Gibbs energy at T = 1000 K according to the Temkin-Schwartzman method, using formula (20)

Let's substitute the values from formulas (12.0)-(12.3), (10.1), (11.1), (19.1)-(19.4)

∆ G ⁰ ₂₉₈ <0, the process at T =1000K proceeds in the forward direction

3) The resulting lithium hydride will react with the nanoshell silica according to formula (22).

(22)

1) Let's calculate the thermal effect of reaction (22)

Let's substitute the data from Table 1

(23.1)

2) Calculate entropy

Let's substitute the data from Table 1

(24.1)

3) Let's calculate the Gibbs energy at T =1000 K

(25)

(26)

∆ G ⁰ ₂₉₈ <0, the process at T =1000 K proceeds in the forward direction

The result of the work done was the study of the properties of tritium-regenerating ceramics consisting of silica globules. The calculated Gibbs energies of the proposed reactions at T = 1000 K are presented in Table 2.

table 2 Reaction formula Gibbs energy ∆ G ⁰ ₂₉₈ kJ/mol -220.36 -14894.544 -1142.06

Presentation of the calculation results in Table 2 showed the possibility of reactions occurring at T = 1000 K. Note that the most possible reaction is the formation of lithium hydride, which significantly complicates the production of tritium, since the resulting tritium, when lithium is irradiated with neutrons, immediately reacts with the surrounding lithium

However, we note that when separating lithium hydride from lithium, the incoming lithium hydride with silica releases free tritium, which can already be collected in its pure form. Since SiO ₂ ceramics become Li ₂ SiO ₃ during the operation of the technical solution, by irradiating it with neutrons it is possible to obtain pure tritium. Thus, SiO ₂ ceramics are reused, which increases the amount of tritium produced. To assess the effectiveness of the proposed technical solution, let us turn to the work [RESEARCH OF THE PROPERTIES OF LITHIUM-CONTAINING CERAMICS PROPOSED FOR USE IN BLANKETS OF RUSSIAN THERMONUCLEAR REACTORS AND ASSESSMENT OF THEIR INFLUENCE ON TECHNOLOGICAL SYSTEMS OF REACTORS V.K. Kapyshev, April 17, 2003], as can be seen from the study, ceramics based on Li ₄ SiO ₄ and Li ₂ SiO ₃ have high productivity when irradiated with a thermal neutron flux of 5⋅10 ¹³ neutrons/cm ³ for 376 days. 2200 cm ³ and 620 cm ³ of tritium were produced, respectively. These indicators are the most effective among the ceramics presented. However, during operation, lithium inevitably burns out ≈ 70%, so it is necessary to periodically replace burnt-out ceramics during operation.

Carrying out the invention

The ceramic blanket module for a fusion reactor consists of a first wall [1] that is in direct contact with the plasma inside the fusion reactor or with the neutron flux from the breeder reactor. The wall must consist of a refractory material, since high temperatures occur during operation of the order of 10 ³ ⋅ ° C

Behind the refractory plate, lithium circulates, which is irradiated by a neutron flux. A plate made of a temperature-conducting material [2] is installed adjacent to the wall; in this configuration, an aluminum alloy is assumed; this proposal will increase the heat removal from the lithium circulation exposed to the heat flow and the refractory walls (Figure 1).

Lithium, due to a nuclear reaction (8), forms tritium, which, in the process of a chemical reaction with surrounding lithium (9), forms a hydride. The mixture of liquid lithium and hydride will enter the storage tank [3], where at a temperature of 1000K evaporation occurs into the cavity above the tank, through the separator [4]. In the cavity, the hydride reacts with ceramics (22) [5], forming lithium orthosilicate inside the globular structure and free tritium, which is subsequently pumped into the required volume. Silica ceramics, during operation, become lithium orthosilicate, which is subsequently irradiated with neutrons to produce tritium (Figure 2).

Thus, the proposed technical solution makes it possible to increase the amount of tritium production, reduce the cost of the operation process using the cyclic use of lithium and the dual use of tritium-regenerating ceramics. This does not require the creation of new unique equipment; existing proven technologies can be used.

Claims (1)

A ceramic blanket module for a thermonuclear reactor, consisting of a first wall [1] made of a refractory material, behind which lithium irradiated by a neutron flux circulates; thermoregulation is carried out by a plate made of a temperature-conducting material [2], and tritium forms lithium hydride, reacting with the surrounding lithium , in turn, a mixture of lithium and lithium hydride, entering the storage tank [3], evaporates into the cavity above the storage tank, through a separator [4], where it reacts with porous ceramics [5], which differs in that consists of a globular structure, and during the reaction, tritium and lithium orthosilicate are formed, which differs in that it is subsequently irradiated with neutrons to additionally produce tritium.