JP2858398B2 - Hybrid fission reactor and fusion system. - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a nuclear reactor, a nuclear fuel,
It belongs to the technical field of nuclear power generation, nuclear fusion and hybrid system of nuclear fission reactor and fusion.

[0002]

BACKGROUND OF THE INVENTION Originally, fission and nuclear fusion is technology different at based on different principles, both hybrid system features and <br/> or activity of have been studied conventionally. However, most of them use thermal neutrons from the reactor to produce tritium from lithium or its compounds, and guide this tritium to a fusion device such as a tokamak to use it for the fusion reaction, or vice versa. Uranium-238 is fissioned using fast neutrons generated at
Or make plutonium-239 from uranium-238,
This is a hybrid system that uses this as fuel for nuclear reactors. Therefore, as described in claim 1 and claim 2, tritium is produced in the reactor core by using lithium deuteride as a part of the reactor core fuel or the reactivity control material. At the same time, there is no attempt to activate tritium and deuterium and cause a nuclear fusion reaction in solid-state lithium deuteride. Also, there are only research reports on fusion systems using lasers and explosion shock waves for hybrid systems using lithium deuterium. Regarding claim 3, conventionally, a loop using liquid lithium or the like as a fluid is formed, and a part of the loop is passed through a reactor core to produce tritium for nuclear fusion. However, there is no example of a loop using deuterium such as lithium as a fluid, and no attempt has been made to generate heat by performing a nuclear fusion reaction of tritium and deuterium nuclei in the reactor part of the loop.

[0003] Regarding fusion, research on plasma fusion of tritium and deuterium has succeeded in achieving criticality in a very short time. However, only a small output was obtained for a large input, and it was still a long time. They have not succeeded in maintaining critical conditions across the board. On the other hand, for cold fusion,
Although not yet officially recognized as a fusion reaction, when deuterium is absorbed in a palladium electrode at a molar ratio of 0.8 or more by electrolysis of an aqueous solution of heavy water, anomalies that are thought to be due to nuclear fusion of deuterium nuclei. A fever was occasionally seen. This reaction does not always occur and is uncertain,
This suggests that the fusion reaction may be caused by the absorbed deuterium even in solid metals at room temperature.

[0004]

At present, plasma fusion using a tokamak apparatus is considered to be the most advanced in nuclear fusion research. In the plasma fusion of tritium and deuterium, which is considered the easiest, the ignition temperature is 45 million degrees (about 4.5 keV). According to Lawson's law, the plasma temperature is 100 million as a critical condition for the fusion reaction. When the plasma density is 10 ¹⁴ / cm ^{3 at} a temperature (about 10 keV), the plasma holding time is set to 1 to 2 seconds. According to Baum's theory, when the plasma temperature is 50 million degrees, the critical time is 3.2 seconds. That is, if tritium and deuterium are kept in an ultra-high temperature state with a density of 10 ¹⁴ / cm ³ or more and a kinetic energy of 5 keV or more for a certain time,
The nuclear fusion reaction due to collision of both nuclei can be maintained in a critical state. In order to generate and maintain such high-density and ultrahigh-temperature plasma, a large-sized tokamak apparatus and large power equipment are required. On the other hand, cold fusion research suggests that deuterium absorbed in large amounts in solid metals at room temperature may cause a fusion reaction during electrolysis, but this reaction rarely occurs. It doesn't always happen. Therefore, the problem to be solved by the present invention is 10
Tritium and deuterium atoms are kept at a close distance for a long time at a density of ¹⁴ / cm ³ or more, and 50 million degrees, that is, about 5 keV or more of kinetic energy is applied to these atoms to cause collision. This makes it possible to cause a nuclear fusion reaction.

[0005]

As a means for stably maintaining tritium and deuterium at a high density for a long period of time, the present invention relates to a first aspect.
And the solid phase described in claim 2 or the liquid phase deuterium lithium described in claim 3 is used. Lithium hydride, which has almost the same properties as deuterium hydride, has a melting point of 689 ° C.

Embedded image And a lattice constant of 400 ° C.
Is an ionic crystal having a covalent bonding property of 4.116 A at 4.16 A and 4.188 A at 600 ° C. The ionic radius by poling is as large as 0.60 A for positive lithium ions and 2.08 A for negative hydrogen ions, and hydrogen ions are present in a form surrounding the lithium ions.

[0006] Natural lysium has an atom having a mass number of 6.
4% and 92.6% of atoms having a mass number of 7 are contained, but lithium-6 reacts with thermal neutrons with a reaction cross section of 940 burn.

Embedded image To produce tritium. Therefore, in order for the density of tritium to be 10 ¹⁴ / cm ³ or more, lithium deuteride highly concentrated lithium-6 is required.

Or

Or a deuterated natural lysium in which deuterium is partially replaced with tritium

Embedded image or

Embedded image may be used. For example, 10
Irradiation of 0% -concentrated 1 cm ³ (about 0.8 g) of lithium deuterium with a thermal neutron flux of 10 ¹³ / cm ³ · sec produces tritium at a rate of about 5.6 × 10 ¹⁴ per second. Is done.

On the other hand, the nuclei of tritium and deuterium have 5,
In order to provide kinetic energy of 5 keV or more corresponding to 10 million degrees, recoil energy at the time of tritium generation from lithium by fast neutron irradiation and thermal neutrons of a reactor is used. Fast neutrons generated by the fission of uranium-235 have an average energy of 2 MeV, are decelerated by elastic collisions with deuterium, tritium and lithium, and at the same time impart kinetic energy to the colliding atom. In the case of deuterium alone, assuming that half of the kinetic energy of fast neutrons is given to deuterium nuclei by collision due to the difference in mass, the production rate of deuterium nuclei having kinetic energy of 5 keV to 1 MeV is determined by the speed in the reactor. When the neutron flux intensity is 10 ¹³ / cm ³ · sec, about 7 × 10 ¹³ /
cm ³ · sec. Since the deuterium nucleus having a kinetic energy close to 1 MeV repeats collision many times, the production rate of the deuterium nucleus having a kinetic energy of 5 keV or more is likely to exceed 10 ¹⁴ / cm ³ · sec. . Note that if a fast neutron reactor is used as the reactor, a fast neutron flux intensity of about 10 ¹⁴ / cm ³ · sec can be easily obtained, but the tritium generation rate decreases because it depends mainly on the thermal neutron flux intensity. Since tritium has a lower density in hydrides of deuterium than deuterium and has a large mass, the number of tritium nuclei that can obtain a kinetic energy of 5 keV or more by collision with fast neutrons in a reactor is the number of deuterium nuclei. It is considered to be considerably smaller than in the case of. However, tritium is lithium-
At the time of generation from 6, the ion collides with surrounding deuterium atoms with a recoil energy of 2.73 MeV, so that the generation rate of tritium itself is more important than activation by collision with fast neutrons. Therefore, it can be expected that the probability of nuclear fusion reaction between tritium and deuterium nuclei in a nuclear reactor is sufficiently high. Further, once the nuclear fusion reaction between tritium and deuterium occurs, the reaction releases fast neutrons of 14 MeV, so that the fusion reaction can be expected to continue.

[0008] When tritium is produced by the nuclear reaction of lithium with neutrons, it simultaneously emits alpha particles (helium-4 nuclei). Tritium itself is also 1
It spontaneously decays to helium-3 with a half-life of 2.8 years. Since helium-3 has a large thermal neutron absorption cross section, its accumulation will be a major obstacle to tritium production. On the other hand, if helium-4 accumulates, it interferes with the collision of fast neutrons with deuterium and tritium, so helium must be removed promptly. Helium easily permeates and diffuses and has a low affinity for lysium, so it evaporates easily at the temperature at which it will be used.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Claim 1 refers to pellets such as uranium dioxide, uranium dioxide containing gadolinia, and uranium-plutonium mixed oxide currently used as fuel in nuclear reactors such as light water reactors and fast breeder reactors. Instead, the powder or pellets of lithium deuteride according to claim 1 is used as a part of the fuel constituting the core of the nuclear reactor. In this case, for example, three usage methods can be considered. That is, (1) As shown in FIG.
Uranium dioxide pellets and lithium deuteride pellets are mixed in one fuel rod. (2) Insert a small number of fuel rods consisting only of powder or pellets of lithium deuteride into appropriate positions in the fuel assembly. (3)
A fuel assembly consisting of powder or pellets of lithium deuteride in all fuel rods is placed in a minority at an appropriate position in the reactor core. Regarding “claim 2”, instead of boron carbide, hafnium, cadmium, etc. used as a material for controlling the reactivity of a thermal neutron reactor, the powder or pellets of the deuterated lithium of claim 2 are used. Used. For example, they are put into a control rod of a nuclear reactor, and at the same time as the reactivity is controlled, tritium is generated from lithium to cause a fusion reaction with deuterium. "Claim 3"
For example, as shown in FIG. 2, a circulating device (hereinafter, referred to as a loop) that partially passes through the core of a nuclear reactor and uses the deuterated lithium of claim 3 as a fluid.
The fluid is heated to 690 ° C or higher and used as a melt,
Alternatively, it is heated to a melting point of lithium of 180.6 ° C. or more and used as a slurry. The fluid circulating in the loop passes through the reactor core to produce tritium from lithium by neutrons in the reactor, and the activated deuterium and tritium nuclei in the reactor undergo a nuclear fusion reaction to generate heat. Occur. This heat is removed by a heat exchanger in the outer portion of the loop and a heater regulates the fluid reactor inlet temperature. The feature of this loop is that tritium, deuterium and lithium can be supplied to the system at any time, so that these concentrations in the loop can always be maintained at predetermined values. However, because of the use of fluids containing active elements such as lithium at elevated temperatures, such loops are not suitable for use in liquid sodium-cooled reactors, such as fast breeder reactors, but in light water reactors. I have.

[0010]

If the present invention is put to practical use, there is an effect that the amount of nuclear fuel material used for nuclear power generation and the amount of radioactive waste generated can be reduced. It will also open up new fields of fusion that are neither plasma fusion nor cold fusion.

[Brief description of the drawings]

FIG. 1 is an example of a sectional view of a fuel rod of a nuclear reactor in which pellets of uranium dioxide and lithium deuteride according to claim 1 are mixed.

FIG. 2 is an example of a hybrid system using a circulating device according to claim 3;

Claims (3)

(57) [Claims] Claims 1. As a part of the fuel constituting the core of a thermal neutron reactor such as a light water type nuclear power reactor and a fast neutron reactor such as a fast breeder reactor, natural lithium or lithium enriched with lithium having a mass number of 6 is used. Hydride Or deuterium of lithium in which part of deuterium is replaced by tritium Powder or pellets. A hybrid fission reactor and fusion system that generates tritium from lithium by neutrons in the reactor and generates heat by performing a nuclear fusion reaction between activated tritium and deuterium nuclei in the reactor. 2. As a material for controlling the reactivity of a thermal neutron reactor such as a light water type nuclear power reactor, lysium obtained by enriching lithium having a mass number of 6 among the hydrides of lithium described in claim 1 is used. Use deuterated powder or pellets. Utilizing the large thermal neutron absorption cross section of lithium-6 to control the reactivity of the reactor and generate tritium,
A hybrid fission reactor and fusion system that generates heat by performing a nuclear fusion reaction between activated tritium and deuterium nuclei in a nuclear reactor. 3. A deuterium lysium enriched with natural lysium or lithium having a mass number of 6 Or deuterium of lithium in which part of deuterium is replaced by tritium A part of the circulation device passes through the core of the nuclear reactor. A hybrid fission reactor and fusion system that generates tritium from lithium in the core portion of the circulation device and generates heat by a nuclear fusion reaction of activated tritium and deuterium nuclei.