JPS58129395A - Thermonuclear-nuclear fission hybrid reactor and its energy generation method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a fast fission blanket for a fusion-fission reactor that uses fissile material at an equilibrium concentration in the blanket to enable continuous operation at the same power density without replacing the fission fuel. This invention relates to a nuclear fusion-fission hybrid nuclear reactor.

A conventional fusion reactor surrounds the plasma generation part of the reactor core and forms an empty vessel with a first barrier, around which a blanket, reflective layer, and shielding layer are installed, and a toroidal magnetic field coil and a boroidal magnetic field coil in the length. However, such a fusion reactor has a low power density, and the 11111
There is a drawback that the load applied to I11 becomes excessive.

A hybrid nuclear fusion-fission reactor was proposed in order to extract energy by extremely high output density by combining the energy generation methods of nuclear fusion and nuclear fission. Simply put, this fusion-fission hybrid reactor has a blanket containing nuclear fuel material or fission material surrounding the metal plasma in the reactor core so that the neutrons generated by the compound fusion reaction can be intercepted and utilized. It refers to a nuclear fusion reactor.

The elements that make up a fusion reactor can be roughly divided into: (1) Core plasma generation section (2) No. 111 and structural materials (3) Blanket and shielding layer What are these components? ! ! A hybrid reactor system is constructed through these relationships. The first core plasma generator is the core of the Im fusion reactor, and is roughly divided into a plasma magnetic field confinement type and a plasma inertial confinement type.

Plasma magnetic field confinement methods include tokamak insects, stellarator treatment, nuclear fusion reactors, and tandem mirror ms.
There are fusion reactors, and laser fusion reactors that use the inertial confinement method of plasma.

Since the present invention does not relate to a core plasma generator, this may be optional, and the present invention mainly lies in the structure of the blank nut and the method for extracting energy from it.

As mentioned above, conventional fusion reactors have the drawbacks of low power density and excessive first wall load. Here, as in a nuclear fusion-fission hybrid reactor, it is possible to multiply the energy by using fissile material as a blanket, and it is possible to achieve a high power density with a low first wall load, and to generate energy on the ground. is possible.

If such a hybrid nuclear reactor were to adopt a nuclear fission blanket system using natural uranium or the like as a blanket, the output would increase with combustion. Another disadvantage is that the spatial density distribution is not flat.

I will list the shortcomings of conventional fusion-fission hybrid reactors next week.

(1) In fast fission blankets using natural uranium, etc., plutonium accumulates during operation, so Prankera F
The output increases with operation.

In order to meet this demand, the capacity of the turbine must be increased from the beginning, which is uneconomical. It is desirable that the output does not change with operation.

(2) The gradient of the spatial distribution of the output in the blank decreases exponentially with distance in methods other than the present invention.

As a result, it was necessary to have an extremely large amount on one side near the cold plasma side, and a small amount on the other side.Also, there was a drawback in terms of efficient use of space.

(8) Since the characteristics change with combustion (with operation), it was necessary to replace the fuel and rearrange the fuel.

(4) In the conventional method, in order to ensure tritium self-sufficiency, it is necessary to use 6L1 enriched Ll, use heavy water with low neutron absorption as a coolant, and take as much blanket area as possible. Met.

(5) The energy multiplication factor in a conventional hybrid nuclear reactor is 10 to sO, and considering power generation efficiency, this level cannot be said to be sufficient for an energy production device.

In order to improve the above-mentioned points, the present invention maintains fissile material at an equilibrium concentration in the blanket of a nuclear fusion-fission hybrid reactor, intercepts neutrons generated from the core plasma, and removes fissile material. Fission is caused in the material, the parent material (uranium-288, etc.) is converted into fissile material (plu)nium II), and the result is a long period of more than 10 years as a result of balancing the production of fissile material and the depletion of fissile material. This made it possible to operate without refueling for a long time. Here, the ill th neutron load is 0.
In the case of 5 Mw/mIW degrees, operation without refueling is possible during the plant life. This is because fast breeder reactors (nuclear fission reactors), which are currently being commercialized, maintain criticality.
This is a great advantage compared to the disadvantage of having to replace the fuel with new fuel every year.

The effect of fission products accumulating with combustion is that if fissile material is used at a concentration slightly lower than the equilibrium concentration, the production of fissile material cancels out its consumption and the effect of accumulating knowledge of fission production, causing the reactor's Output can be kept constant for a long period of time.

The object of the present invention is to achieve long-term constant output combustion in order to generate energy such as power generation in an economical manner in an aim joint furnace.

The present invention consists of a reactor core plasma generation soil section, a blanket and a shielding layer surrounding it, and the blanket mainly includes a nuclear fuel layer containing fissile material and a tritium breeding layer provided as necessary. It consists of a nuclear fuel production layer, a reflector layer, etc., and the fissile material contained in the II fuel layer is held in advance at an equilibrium concentration or a little lower than the equilibrium concentration, that is, a little lower than the equilibrium concentration to cancel out the fission product II product effect. By doing so, the fissile material produced by the neutrons supplied from the fusion plasma is balanced with the fissile material consumed, and nuclear fusion generates energy continuously for a long period of time without replenishing nuclear fuel. −
It features an energy generation method using a nuclear fission hybrid reactor.

Another object of the present invention is that the reactor core is composed of a plasma generating part, a blanket and a shielding layer surrounding the core, a superconducting magnet, the blanket having a thickness of 1 mm, a nuclear fuel layer containing fissile material, The fissile material in the fueled layer is composed of a reflector layer, and the fissile material in the fuel layer is configured such that the fissile material generated by neutrons supplied from the fusion plasma and the fissile material consumed in the nuclear fuel layer are balanced. Nuclear fusion - Nuclear branch hybrid) l [Providing a child reactor.

Another object of the present invention is to arrange a tritium breeding layer or a nuclear fuel production layer after the nuclear fuel layer in the blank of the hybrid reactor, thereby improving the thorium production rate or making it possible to produce nuclear fuel. The objective is to provide a nuclear fusion-fission hybrid nuclear reactor.

Another object of the present invention is to provide the blanket for the hybrid nuclear reactor, wherein the nuclear fuel layer includes nuclear source material and fissile material, and maintains the concentration of the fissile material at an equilibrium concentration, thereby producing a nuclear fusion-fission hybrid reactor. is to provide.

The principles, structure, and operation of the 1m fusion-fission hybrid nuclear reactor and its energy generation method of the present invention will be explained in detail below. Light nuclei of deuterium (D) and tritium (T) fuse to form another atomic nucleus. The difference in the mass of the atomic nucleus before and after the reaction is released as energy. This is called a fusion reaction. This relationship is given by the well-known Einstein's relational formula (1). where lc: energy, m: mass, C
:Shows a leader〇When a heavy nucleus such as uranium splits into three, the difference in mass is released as energy. This is called a nuclear fission reaction. At this time, 14 or more neutrons are emitted. The nuclear fusion reaction using deuterium (CD) and tritium (T) is demonstrated as follows.

/ / D + T -4α (8, H) [eV ) ten neutrons (14,
06MeV)-(2) Much of the energy of the nuclear fusion reaction is dissipated by neutrons. This neutron is 14.06
It is a fast neutron with an energy of MeV (t ion electron volt). On the other hand, alpha particles (nuclei of helium He), which are atomic nuclei formed by fusion, are also 8.1iBM.
It has an energy of eV, but since this is a flight, energy is released in the 11111 (or first gap #!) between the plasma and the blanket. In the fusion reactor, Prankella F
But the book, which releases energy by deceleration at.

Since the nuclear fusion-fission hybrid reactor (hereinafter referred to as hybrid reactor) of the invention uses a blanket containing nuclear fuel, the subsequent nuclear fission reaction generates more energy than a conventional nuclear fusion reactor.

For example, when uranium is used as a nuclear fuel, U10 neutron → i fission fragment oy, s & ev) + rll (6M
eV) ±8th radiated neutron (5M6V) - neutrino (
11 MeV ) --------, ----- (8) A total energy of about 19 o MeV Ng 00 ) [eV is generated. As a result, the energy generated by the fusion reaction is greatly increased when nuclear fuel is used in the blanket.

There are eight combinations of nuclear fuel material compositions.

(13 Uranium (U) contains plutonium (Pu) (Uranium υ is converted to Pu, (2) Tric A (Th) rp;-') 9X-tMus8B (Ba
8U) (thorium (Th) is 288
(conversion to U), reaction (1) is currently used. The form of fuel is usually solid (metal, oxide υ0-PuO2, carbide UO-Pu0
1 Other silicides such as u, si-Pu, si, etc.
The use of molten salts also exists in the case of thorium systems.

(Example: ThF 11% Ba1l, 16%
The composition of LiF 7ji%) plasma generation fuel is usually deuterium (D) and tritium (T), but it is also possible to use deuterium, deuterium D1 protons (P), and borine (B) as fuel. be. A typical plasma generating fuel has a composition of deuterium and tritium. In the case of normal D and T, it is necessary to make T (tritium), and for this purpose it is necessary to put lithium (Ll) into the blanket. This composition is also lithium oxide (Li, O)
, metallic lithium, L, i -Pb eutectic, lithium silicate, lithium aluminate, etc. There are two types of lithium: 6L1 and Ll, and natural lithium contains 7% f1m of 6L1, but in order to multiply tritium in a large amount, a concentrated version of this is sometimes used.

In the fusion reaction between deuterium CD) and tritium (T), 17.68 MeV is generated by one fusion reaction.
14 of them. Oa MeV energy is carried by neutrons. A blanket that receives this energy is placed around the fusion plasma, and the heat generated there is used to generate electricity. The present invention relates to the construction of this blanket.

When uranium thick nuclear fuel material is used in the blanket of a nuclear fusion reactor, nuclear fission occurs due to the neutrons generated by the tIs#11I combined plasma i, and the energy of the narrow neutrons reaches 14 MeV.
On the other hand, nuclear fission generates go o mev energy and the energy is multiplied.

Furthermore, since more than 8.5 neutrons are generated per nuclear fission, these neutrons cause nuclear fission again, and the energy generated in the blanket is far greater than the energy brought into the blanket by the initial fusion neutrons. It turns out. This is called a nuclear reactor for the purpose of energy multiplication.

This nuclear fission reaction can be expressed as follows.

[Fissile sludge] 10 neutrons → 10 fission fragments [2.5 neutrons] + r-rays + β-rays + 800M8V −−−−=−−−
--, (4>Kokote nuclear content 111! 'It substance ha''P
u, ""U, "'U, etc., but if the neutron is a high-energy fast neutron, the parent material SSSυ will also undergo nuclear fission.

The structure of each part of the blanket and the 1m capacity will be explained in more detail.

The blanket is a part placed around the *S* plasma that receives the energy carried by neutrons from the plasma and converts it into heat, as well as producing tritium, which is the fuel for the fusion plasma.

As mentioned above, the blanket of a hybrid reactor consists of a bulkhead fuel layer and a tritium breeding layer, and in some cases a reflector is placed behind it to efficiently breed tritium. First, the barrier wall between the plasma and the plasma has the role of stopping xII and α particles generated by the plasma, and is made of a metal material such as graphite, stainless steel, or TZM.

It has a structure that allows it to be cooled and remove that heat.

The fuel layer consists of nuclear fuel material, structural material (eg stainless steel), and coolant (eg water). Nuclear fuel materials can be depleted uranium or natural uranium mixed with plutonium, or thorium mixed with Ba8U.

Is this nuclear fuel? I negative chemical form is metal, alloy with MO,
Oxides, carbides, silicides, and silicides are considered. It is also possible to form a molten mass.

There are two types of structures for nuclear fuel materials: one is to put the nuclear fuel material inside a tube-shaped structural material and cool the outside of the material, and the other is to have the nuclear fuel material outside and flow a coolant inside the tube. The coolant can be helium, water, heavy water, or liquid gold (inertial confinement type).

The tritium breeding layer is a layer containing lithium (Ll), which is a parent material of tritium (T), and generates tritium (T) through the following reaction between lithium (Ll) and neutrons.

'Li ten neutrons -' He + T + 4.8 M6V
−−−−−−−−−−−−−−−−−(5)'Li+
Neutron -'iie ten τ ten neutron -2,47kieV -
--1-- (6) Deuterium (D) and tritium (T) react and burn in the plasma generating part, and the tritium (T) consumed must be replaced by dilithium produced in this proliferation layer.

Therefore, this tritium breeding layer is composed of a lithium-containing lithium and a structural material (for example, stainless steel and a coolant.The forms of lithium used are metals, silicides, silicides,
Aluminate, alloy with Pb, etc. are being considered. There are two types of tritium breeding layer structures: one in which the coolant flows inside the tube and the other in which it flows outside, but the former is usually adopted.

Coolant is helium, water, heavy water, liquid metal (Liquid lithium metal can be used when lithium metal is inertial confinement)
is possible. The reflector is a layer placed to make tritium multiplication effective and may be omitted if there is no space. Usually Kurofune, beryllium, and water are used. This part also generates heat, so cooling is required. A shielding layer is usually placed on the outside of the reflector to prevent neutrons and r-rays from leaking from the blanket.

Toca! As shown in Fig. 1, the configuration of the hybrid nuclear reactor is as shown in Fig. 1, there are a first partition wall 2, a blanket S1 radiation shielding layer, and a toroidal magnetic field field coil 6, a meloidal magnetic field coil 6, etc. around the core plasma 1. There is a plasma confinement device. 7 is the pillar and 8 is the furnace wall. The core plasma 1 is connected on one side to a heating and fuel supply system and on the other side to an air cooling line and a fuel recovery line, and the blanket 8 is connected to a heat exchanger power generation system for distributing coolant. A tritium (T) recovery line is connected to this heat exchange power generation system, and the recovered tritium is sent to the fuel storage section and fed back to the fuel supply system. Since this part is the same as the configuration of a general fusion reactor, illustration and explanation are omitted.

An example of the configuration of a blanket for a hybrid nuclear reactor according to the principles of the present invention is shown in an enlarged scale in FIG.

In Fig. 2, 1 is the fusion plasma generation part, 2 is @
11i1111, fusion plasma generation part 1 of the reactor core
is in a vacuum vessel surrounded by the 11th IIIis,
Deuterium C, a fuel, generates extremely high temperatures of hundreds of millions of degrees or more.
D) and tritium (T) react to cause a nuclear fusion reaction. This D-? One of the reaction products produced by the reaction is an α particle (Help) with an energy of 8.6 aV.
Since the lE-n nucleus is a charged particle, it is confined for a short time in a strong magnetic field, loses its energy by collision with -118, and eventually diffuses into D-! It leaves the core with the plasma.

In this case, the neutrons, which are the reaction products in cylinder 2, have no electric charge, so they move without being constrained by the magnetic field, and because they have a high energy of 14.06 MeV, they pass through the first V4 wall and enter the blanket behind it. It jumps in and performs the nuclear fission reaction described above.

To describe the structure of the blanket of this hybrid reactor in more detail, as shown in FIG. The outside is surrounded by a shielding layer 4 and a superconducting magnet such as a toroidal magnetic field coil 5.

In FIG. 2, an example of the composition of the blanket and shield layer is as follows.

(1) Partition wall (distance 1!0 from the plasma center)
Ooa, thickness lcga) (2) Fuel layer (thickness 15 cll) containing equilibrium concentration of fissile material
55% stainless steel W14 10% helium 86% (3) Tritium (T) breeding layer (Note: - In this example, the thickness is 50 CI+, but the tritium breeding ratio is 1.0, so it is about 10 cm. ) Li, Oa 5% Stainless steel 10% Helium 25% (4) Reflector layer (thickness 145) Graphite 90% Helium 10% (6) Shielding layer (thickness 1! LoclI) Stainless steel layer - Water attack 10% Lead l-B, 0 1% The combustion characteristics of the fast fission blanket shown in Figure 2 are as shown in Table 1.

Figure 8 shows the change in characteristics when the dependence on the concentration of fissile material contained in the fuel layer is changed in the blanket with the configuration of No. 5tjA, and the horizontal axis is the concentration of PU-189 (
Vo), and the vertical axis shows the relationship between the tritium breeding ratio T, the fissile material production rate (Net) F, and the blanket energy multiplication factor. This blanket is better than this picture! It can be seen that the concentration at which the value becomes zero (equilibrium concentration) is 9% of the pu-sse concentration.

Figure 4 is a diagram showing the spatial heat generation rate distribution characteristics of the blanket, where the horizontal axis is the distance from the plasma center (C illusion), and the vertical axis is the ratio of power density (POWIRDKNSI'l'Y) to fusion neutrons (Mev/ In the figure, 2 is i!
11111! , 1O is the fuel layer, 11 is the reflector layer, and in the figure, the solid line (straight line) is 9
Initial combustion characteristics when % of plutonium (Pu-1io) is added, point 111 (B track It) beam, u+9%pu-
The long dashed line (C curve) shows the combustion characteristics at a burnup of 9 MY (megawatt) years - for depleted uranium (D,
The initial combustion characteristics of only uranium (D, u) with 6% Deltonium A (Pu-use) added to u) are shown. When plutonium is added to depleted uranium at an equilibrium concentration of 9% as shown by the straight and three curves, the combustion characteristics are flat and exhibit favorable characteristics. On the other hand, in the case of only depleted uranium, the power spatial distribution is extremely steep and the characteristics are poor. (Also, the thickness of this layer may be about 10c+++).

If natural uranium is used in the fuel layer, it will contain fissile material that does not have an equilibrium concentration, an example of which is shown in FIG.

Its composition is as follows.

(1) Fuel layer natural uranium ■1 Stainless steel 10 whisper Helium 85% (2) Tritium breeding layer Li, 0 65% Stainless steel 10% Helium 25% (3) &
Projectile graphite 90% helium 10% The combustion characteristics of Prankera F shown in FIG. 5 are as shown in Table 8. As can be seen from this table, for the increment containing fissile material that is not at equilibrium concentration, the characteristics such as energy generation in the blanket (multiplication factor M) and tritium breeding ratio change greatly with combustion, and the equilibrium concentration changes due to the composition of the nuclear fuel layer ( A 15cm nuclear fuel layer containing 58g of plutonium mixed with depleted uranium (depending on the ratio of fuel, structural materials, and coolant) and size.
It is thought that the equilibrium concentration of plutonium will be 9% when the plutonium concentration is used, and that the equilibrium concentration will be about 8% when the fuel layer becomes goc+w. Also, if you mix uranium-1 with silium, the value will be different.

8. Calculating the extreme compositions and compositions is as shown below. % IOJ is obtained as the equilibrium concentration.

Composition (1) Composition In case of light water cooling type blanket (IJ@1
Interval I! Thickness l (2m + (distance from the center of plasma 11200c + *) (2J combustion layer thickness ZOcm"'pu-UO1No % H, 080≦ Stainless steel (SUS Hatake 11) 10% (8) Tritium breeding layer thickness, .Eng' Li 50 attack concentration Li, 0
50% Light water 40% Stainless steel (8US LU 1@) 10% (4) Reflector layer 15cm thick Water (H, O) Plutonium (S LU EP) in a blanket with a composition of 90% or more
The calculated equilibrium concentration of u) is 8.7-.

Composition OU Composition B For helium-cooled bran nuts (No. 17)
111118! JIL sa1 csi (distance from the center of plasma 200 ell) (2) Fuel layer
Thickness 16 cm 119 pu + UO 80% stainless steel (SUS 8163 20% H 1950% (3) Tritium breeding layer thickness 15 le natural Li,
0 60% Stainless steel (SUS 816) 15%He
85% (4) Reflector layer Thickness 16c11 Kurofune The calculated equilibrium concentration of lll'lpu in a blanket with a composition of 100% or more is 10.2%.

The above method for calculating the equilibrium concentration will be explained as follows.

In general, nuclear properties such as neutron behavior and ripe nuclear transmutation can be calculated by solving the following neutron transport equation.

Ω-D91+Σ? (rllC) 9' (rlE I
Q) Here, ψ is the neutron flux, l”ll*Q are variables indicating the location, energy, and angle, respectively, Σ1.Σ8 are the total cross section and scattering cross section of the reaction with neutrons of the atomic nucleus, and S is the neutron source. In this equation, if Σt and Σ8.S are given manually, the neutron flux ψ can be found.Location r□
An electronic computer program is generally used to obtain solutions using variables such as , energy, and angle Q. If the shape becomes complex, it may not be possible to calculate it with the capabilities of current electronic calculators, so it is usually calculated by approximating it to a one-dimensional shape (sphere, infinite cylinder, infinite plate). Although there are many computer programs that solve the above equation in a one-dimensional shape, calculations are performed using a calculation code that solves the neutron transport equation named MuNl5N, which is famous as a nuclear reactor shielding program.

To find the equilibrium concentration, proceed as follows. Now, the concentration of fissile vIIjM (for example, !811pu) in the fuel layer is appropriately selected, and the shape and composition of the blanket material are considered as Σ1. Σ8 is given as an input (S is determined by the plasma conditions). Calculate the neutron flux using the calculation program of MUNE SH. Using this, the production rate and extinction rate of fissile material are tis, and the net fissile 4I5 material production rate r is determined by subtraction.

If this is positive, fissile material will accumulate with operation, so the concentration of fissile material in the fuel layer is slightly reduced and calculations are performed using the MUNl5H calculation program to find F. If this is carried out at a certain point, the concentration at which F becomes almost zero (equilibrium concentration) can be determined.

Figure 6 shows (I) light water cooling blanket (composition) and (1)
) 1llpu with helium cooled planchella) (composition)
FIG. 2 is a characteristic diagram showing the relationship between the concentration, the fissile object image generation rate 1 for fusion neutrons, and the energy multiplication factor M for fusion neutrons. The horizontal axis shows the concentration of 1llilpu (4/
. ), and the fissile material production rate F and energy multiplication rate are shown on the vertical axis.

Equilibrium concentration is determined at the point where the fissile material production is zero. In the case of configuration (I), the equilibrium concentration of fi8@pu is 8
．． 7%, in the case of configuration (1), the equilibrium concentration of pu is 1
It is 0.2%.

As shown in Figure 6, the energy multiplication factors of configuration (I) and configuration (El) are 10 to 16 at equilibrium concentration, which is inferior to the energy multiplication factor of about 44 for the configuration described above. . To determine the range of equilibrium concentrations according to the invention:
The equilibrium concentration of 8% to 11% was considered to be excessive.

The advantages of the nuclear fusion-fission hybrid nuclear reactor of the present invention are as follows.

(IJ) By containing an equilibrium concentration of fissile material in the fuel layer, the production and extinction of fissile material are balanced, allowing operation for long periods without nuclear fuel supply.

(2) Since the fuel layer is placed in the plasma environment and the Plunkett method is adopted, 181U (
F) A large amount of energy can be generated due to the contribution of nuclear fission.

(8) The purpose is to configure the reactor as a hybrid reactor for energy production rather than a fuel production hybrid reactor. This allows long-term operation without refueling (in some cases, the plant Kouki core fuel may not need to be replaced).

(4) The spatial distribution of power in the blanket is flat.

(6) There is little change in output due to combustion (hybrid furnace operation).

(6) The thickness of the blanket can be reduced because the conditions for tritium self-nine wings can be achieved with the lonely tritium breeding layer. Therefore, the size of the furnace can be reduced and construction costs are significantly lowered.

(7) The output density of the blanket is high, and the fusion energy can be multiplied by more than 40 times, making it an economical energy generator.

EXAMPLE The present inventor considered that in order to make a hybrid reactor for energy production economically useful, the power density should be increased. Based on the premise that the energy multiplication factor will increase with the concentration of fissile material in the fuel, how to determine the concentration of fissile material will reduce the amount of fissile material annihilated by the fission reaction and fission by neutrons in the fission blanket. We investigated the equilibrium concentration at which the fissile material produced by

(11"'Effect of Pu concentration 11 & Nuclear properties of continuous fission blankets as a function of atomic percent of 189pu in depleted uranium.tt
S was performed using a calculation code called 5MI8N that solves the neutron transport equation based on the cross section set taken from the GIOX 40 set. p8s.

An approximation was used. The hybrid infinite cylinder model is shown in Figure 6. The plasma neutron source is uniformly distributed in the central 170C11 cylindrical area. The first wall score was 9. The fuel layer and tritium breeding layer are 15 and 50, respectively.
The thickness was +2. The calculation results are shown in Figure 8. The net fissile material production rate is almost zero at j189puo@child%. At equilibrium concentration, the energy multiplication factor and tritium multiplication ratio are approximately 40 and 8.5. The tritium breeding ratio is much worse than 1.0. 80m1 and 15c11 thick tritium increase*
m is used, the tritium breeding ratio is 1.0, respectively.
5 and 1.79. From this, it can be seen that the tritium breeding layer should be as long as 50 cm (about 10 cm is sufficient.
sg, indicating that they are sufficiently subcritical.

(2) Combustion characteristics The combustion of uranium, thorium, and lithium was calculated. The equation of the nuclear chain was solved using the neutron flux calculated by 5Nl5H. Fission products were not taken into account in this study, in which the calculated atomic density of msw was used to calculate the neutron flux in the next stage.

The combustion characteristics of the nuclear reactor are shown in Table 1. Although fission products are not considered in the calculations, the results indicate that the blanket energy multiplication factor does not change with irradiation. Therefore, for long-term operation at a nearly constant output level,
It will probably be possible to operate for more than 10 years without changing fuel. If the wall load is 0.8 ) Elf/, s, the reactor can operate without refueling for 80 years of the plant's life. Also, if the initial concentration of plutonium is taken slightly below the equilibrium value, the effects of fission product accumulation will be counteracted by the accumulation of plutonium.

89 Figure 4 shows the spatial heat generation rate distribution. The distribution when using Pu 5% and O whisper is also shown. It can be seen that when 189pu9% is used, the output distribution becomes flat. The distribution becomes flatter as combustion progresses. The maximum power density of the fuel layer is 817 kW/, which is similar to the value of a fast breeder reactor. This type of hybrid has the following advantages:

■ Long-term operation at a nearly constant output level is possible without changing fuel.

■ The period in which the blanket output of conventional fast nuclear fission hybrids increases with combustion is eliminated.

■ Spatial flattening of the output of the fuel layer is achieved.

■ The power density of the fuel layer is sufficiently high.

■ Reduces the need for fuel reprocessing.

■ Easily achieve tritium self-sufficiency.

The thickness of tritium multiplication can be reduced. Reducing reactor dimensions reduces capital costs.

A disadvantage of hybrid reactors for energy production may be safety issues such as loss of coolant accidents. This episode-
Solving the problem won't be so difficult if you make use of your experience with stubborn nuclear reactors. The initial loading of fissile material into a hybrid reactor is made of manufactured uranium or plutonium discharged from a light water reactor. The plutonium discharged from the light water reactor would be put to better use if it were supplied to the 71 Ibritt reactor. The issue of materials for long-term operation may be resolved because the types of materials are not as limited as those for nuclear fission reactors, which must maintain criticality.

(3) Conclusion We proposed the fast fission blanket concept of a fusion-fission hybrid reactor for energy production using fissile material in the fuel layer at a concentration at which the production and extinction of fissile material are equal (equilibrium concentration), and investigated the nuclear properties. In the case of a 15c+m fuel layer, equilibrium is reached when the concentration of j8@pu in depleted uranium is about 9%.

At this time, the energy multiplication factor of the blanket is approximately 42,
Even if this burns up to 8N1W/year, the lint remains constant. The tritium proliferation ratio is about 8.6 with a proliferation layer of 50 cm, and self-sufficiency can be achieved with a proliferation layer of about 8 cI11.

Neutron effective multiplication coefficient is O, SOl・Maximum power density is 81
It is 7kW/. This blanket concept has the following advantages:

■ It is possible to operate for a long period of time without changing fuel.

■ There is little change in output due to combustion.

■ Spatial distribution of output is flat.

■ The conditions for tritium's self-propagation can be easily satisfied.

■ The capital cost of the furnace is lower because the blanket can be made thinner.

■ The output density is sufficiently high.

According to the present invention, due to these advantages, many of the drawbacks of conventional nuclear fusion reactors and hybrid Q subreactors can be overcome, and a fusion-fission hybrid reactor can be provided that has high power density, is economically useful, and has high efficiency. It has been confirmed that there is a great industrial advantage in that it enables good energy generation.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the basic configuration of a tokamak withdrawal fusion-branching hybrid nuclear reactor. Figure 2 is a diagram showing the principle of fast nuclear fission using fissile material at an equilibrium concentration in the fusion-fission hybrid reactor of the present invention. A diagram showing an example of the structure of the blanket, FIG.
A diagram showing mineralization characteristics when the concentration of fissile material contained in the fuel layer is changed in a blanket with the configuration shown in the figure. Figure 4 is a spatial heat generation rate distribution characteristic diagram of the same Plunketts F. Figure 5 is a light water cooling 18111pu concentration and fissile material production rate of formula blanket and helium-cooled Planchera F,
A characteristic diagram showing the relationship with the energy multiplication factor, FIG. 6 is a diagram for calculating the blanket characteristics of the present invention, and FIG. 7 is a configuration diagram of the blanket. 1...Reactor core plus! , 2... 11th! 111! , 8
... Blanket, No. ... Shielding layer, 6... Toroidal magnetic field coil, 6.0. Voloidal magnetic field coil, 7
... Strut, 8... Reactor wall, 9... Fuel layer, 10...
- Tritium breeding layer, 11... reflector layer. Cape Applicant President of the University of Tokyo Figure 2 Figure 5 Figure 8 D
MzwPu4A (%)

Claims (1)

[Scope of Claims] L Consists of a reactor core plasma generation part, a blank and a shield layer that destroy it, and a plasma confinement part made of superconducting magnets, etc. It consists of a layer and a tritium breeding layer,
A fissile material that eliminates the concentration of fissile material contained in the nuclear fuel layer of the blanket by a nuclear fission reaction;
Nuclear fraction t produced when neutrons collide with nuclear fuel material
By maintaining the ascus concentration to be equal to the IB quality,
An energy generation method using a nuclear fusion-fission hybrid Fushi reactor, which is characterized by generating energy continuously for a long period of time without replenishing nuclear fuel material. 2. The method of generating energy according to claim 1, wherein the blank comprises a first II wall, a nuclear fuel layer, a tritium breeding layer, and a reflector layer. The energy generation method according to claim 1, wherein the equilibrium concentration of fissionable fluorine contained in the nuclear fuel layer of the blanket is 8 to 11%.