JPS61500380A - Sheet/blanket type reactor - 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] Background of the invention TECHNICAL FIELD The present invention relates to nuclear reactors, and more particularly to nuclear reactors with seed blanket ties. do.

Among the key factors limiting the future use of nuclear reactors for power generation: However, there is an uneconomical way for nuclear reactors to utilize uranium. Ranium burns only a few /4'-cents and is available in its natural state. This is because the supply of uranium is limited. Thorium is about Trying to use thorium as a replacement for uranium since it is three times more abundant Many attempts, mostly unsuccessful, to find attractive ways to This has always been done since the beginning of the Nhattan Project. A summary of this work was published in February 1977. EPRI NF 359's "Pressure Watercolor Atom" can be found in ``Evaluation of Thorium Fuel Cycles in Reactors''. but However, since thorium does not have any natural fissile minerals, thorium oxide is a common source. Highly enriched uranium (basically U-235) must be added to t-thorium oxide. As a result, start The amount of uranium that would be used to Keruyoshi also grows considerably. Additionally, after the core has been depleted, Since there must be some amount of U233 generated, U233 is extracted and 2 After about 30 years, additional The total amount of uranium that must be The level will be the same, and the amount of separation work will be greater. On top of that The fuel required for It is definitely proliferative. Also, U-233i: There is no commercial way to reproduce it. It should also be noted that.

If such commercial methods are developed and used, along with U-233 Because extremely high-energy gamma rays are generated, all work must be done behind heavy shielding. This has to be done by remote control, which can be very expensive. It is expected that

There is also the possibility of using highly enriched uranium, which is less likely to provide initial fissile content. It is being considered to However, this method has an even worse "uranium utilization rate" It has been discovered that it contains uranium, resulting in additional uranium This will create a huge need.

For example, in September 1964, Double Knee PDL (V/APD L) PR) %19 in the report on the 256 large power reactor (LI)R) project. On October 27, 1964, Alvin Radkovski U.S. Patent No. 3,154,471, issued to Vinny 2 Dokovski (A, Radkovs'ky).

G Double/% Tardigg (G, W, Hardigg) and R.E. Geneva II P2 by Ruth (R,E-Luc*) TRI Attempts have also been made to utilize the seed blanket concept for fuels. easy In other words, a seeded blanket reactor consists of a seed region of fissile material and a neutral A blanket region of fuel parent material that can be converted to fissile material by child capture. Including area. Fissile materials undergo nuclear fission using neutrons with energy below IMED. Therefore, naturally occurring fissile material comprises only 0.71' of naturally occurring uranium. U-235, which will be formed.

The remaining part is U-238. Converted to fissile material by neutron capture The parent fuel materials that can be used are uranium-233 and plutonium-239, respectively. Contains thorium-232 and uranium-238 which are converted into fissile material. -C In a de-blanket type reactor, the seed consists of a small volume, but It is sufficiently concentrated to the point where it approaches criticality. The first two seed blankets The reactor core is located in Shippingpaw, Pennsylvania, USA. t), highly enriched uranium fuel for seed and f2 tanket. Constructed from natural uranium.

However, as reported in the aforementioned publication.

A blanket of natural thorium and a blanket of thorium with a small amount of natural uranium. One study has also been conducted using a lanket. However, ordinary uranium Compared to the reactor core, the initial amount of uranium added in these cores is very however, the power density is much lower and the fuel utilization is about the same.

In addition, highly enriched uranium gold is used in the seed and U-gold is used in the depleted blanket. There is a possibility of neutron multiplication due to the presence of 233.

Other seeded blanket core designs, namely the 1975 “Light Water Breeder Reactor” In "Safety Analysis Report on Shipping Port Atomic Stations".

and light water version of ERDA' 1541 in June 1976 Light water breeder reactor (LWBR) as described in the final status statement of the breeder reactor project The reactor core has been in operation for at least 80 years, and is the early stage of a large site that will be regenerated in a continuous manner. As the added uranium utilization rate, this increases the uranium utilization rate to the normal In addition, the core power density is relatively low and the fuel is Proliferative at every stage.

Purpose of invention It is an object of the present invention to develop a new seed seed for nuclear reactors which has several advantages in this respect. The objective is to provide a blanket core design. In detail, the purpose of the present invention is to make itself oriented towards the use of non-breeder fuels.

Enables superior uranium utilization, provides typical overall power density and adds A new seeded blanket core that requires a lower initial amount of uranium The objective is to provide a nuclear reactor with

Summary of the invention According to a broad aspect of the invention, a seed region of fissile material and neutron capture provide nuclear comprising a blanket region of fuel parent material capable of being converted into fissile material; A nuclear reactor is provided having a reactor core with a seed region and a blanket region. There exist so as to create a net 6 reverse flow of neutron flow, in which.

The net's high-speed neutron flow flows from the blanket region to the seed region, and the net's heat The flow of neutrons and 'evithermal neutrons is from the seed region to the blanket region. t-Characteristics.

As explained below, especially in the “Theoretical Considerations” section, the conventional In a de-blanket reactor, the brightness of thermal neutrons from the blanket to the seed is There is a certain flow. In other words, the fast neutron flow of Netsu F moves from the seed region to the blanket region. net thermal neutrons and thermal neutrons from the Nagashima blanket region. to the seed area. In the reactor of the invention, reversal is not a fact, i.e. The fast neutron flow of the net is 1L net thermal neutron flow from the blanket region to the seed region. and the ebithermal neutron flow is from the seed region to the blanket region. Will be mentioned later The use of reversed neutron flow is an excellent choice for the use of non-breeding fuels, as Uranium utilization rate.

Well adapted to normal total power density, low initial requirements of uranium added and In particular, seeded blanket reactor cores in which the blanket region contains thorium Let's make it.

The invention will be described below with particular reference to light water reactors, where @water is in contact with the seed region. It is used as a coolant and moderator in the packet region, and the reversing neutron flow is 3.0: Seed water to fuel volume ratio within the range of 1 to 9.0:1 and 0.8:l to 2.0 : made by providing a blanket water-to-fuel volume ratio within the range of 1. Ru. In the preferred embodiment described below, the water to fuel volume ratio is 9: 1, the blanket water to fuel volume ratio #it:1. seed macro thermoabsorption 20% enriched urani yield is sufficient for a typical refueling period of about 1 year to 18 months (which is the maximum for non-propagation). Ru. For thermal neutronization, the probability of escaping resonance (pB) is kept close to the same value as 1c. the heat leakage flow ratio is sufficiently large at the Kana plutonium is generated in seeds as described below. Thus the seed The fuel inside is pumped out to be reprocessed and reused, and as a result of reprocessing Insufficient plutonium is formed in the seed which presents a growth problem. seed The volume is approximately 1.4 to 1.8, which corresponds to a multiplication factor (kS) in the seeded infinite medium. It is selected under mathematical conditions to be within the range of 15% to 25cm of the core volume.

The seed area can remain static and the control is to prevent combustible poisons in the seed. It should be done with a focus on quality and control. This device has low power density during seeding. By creating a high temperature, the resulting fuel volume is reduced to a large proportion of the water in the seed area. However, it is suitable for heat transport.

In order to obtain a large negative heat flow, the blanket should be The ratio of chromium absorption should be higher. Thorium blankets should be extremely It can adapt well to such conditions without going all the way to the grid. This is a valid trivia This is because the cross-sectional area of U-238 is much larger than that of U-238. uranium lattice glatonium has a macroscopic absorption cross section that almost matches that of U-238. U-233 has a macro cross section of thorium, so that it increases as it has a convergent cross section. They increase so that they have approximately the same macroscopic cross-sectional area.

To have a good initial power share within the thorium blanket, U-233 is approximately 1.5chi~2. The value of the multiplication factor at which thorium increases until it approaches the double-sided concentration of O Generally speaking, it is necessary to multiply thorium. The value of this multiplication factor is approximately 0.9.

A preferred embodiment uses about 10% uranium enriched to about 10% U-235. , thereby providing two-way production for U-235 in thorium. like this Using a blanket fuel with a strong inversion thermal neutron (to the blanket) can be obtained with a blanket water to fuel volume ratio of 1:1. child hk) in the normal range, and in the very tight cases used in LWBR. If the reverse thermal neutron flow t-generated in the uranium blanket is disadvantages in structure or thermal behavior, such as when required to The initial 8 t of U-238 content in the thorium blanket was Formed in the blanket, fcU-233 is strongly denatured and there is no separation of isotopes. ensure that it cannot be used as a weapon. The use of reverse heat flow is Although it is created in the lanket and reduces the m of *U-233, For each neutron absorbed by U-233, low values resulting from high values of average ′#j,) and large thermal neutronization Protactinium capture increases the blanket multiplication factor, so river The use of heat flow does not reduce the blanket multiplication factor.

Some preferred embodiments of the invention are described below.

However, at this point there is a discussion of some theoretical considerations regarding the invention and its many advantages. It is believed that it allows for better understanding.

Theoretical considerations Power sharing between seeds and blankets> Since all the output is generated by consuming lanium, the back From the standpoint of nitrogen utilization, it is important to maximize all and part of the core output and power generated in the blanket. It is very important to make it large. on the output between the seed region and the blanket region. The usual equation (first equation) used to determine the splitting is as follows.

Here, PB/P8 is the ratio of blanket output to seed output.

ks is the glue in the seed, the value of (multiplication factor in infinite medium), and hLkB is the blank. This is boiled water in the cut. The core is assumed to be in critical condition. This formula is a high bran The main factor in obtaining the ket power part is 0 to the first high blanket, l The second shows that a high seed can be zero. However, this and other There are many issues.

That revelation is provided in the second formula below. (It would be small compared to the large core (Leakage from the core to the outside is ignored) Here, akBS” indicates the leakage of thermal (slow) neutrons from the blanket to the seed. , given by the following equation.

where e is the blanket high speed effect.

The superscripts S and B correspond to Seed and Planchera F, respectively.

k is a value of 0 in that region. Seed blanket assembly is in critical condition Assume that it is possible.

Σ is the macroscopic heat absorption cross section.

D is a thermal diffusion constant.

pB is the probability of escaping resonance in the blanket.

ps is the probability of escaping resonance in the seed.

ν8 is the number of neutrons emitted for fission in the seed.

ν3 is the number of neutrons emitted for nuclear fission in the blanket.

The latter value "v" remains substantially the same for U-233 and U-235. and In our case, S/C8 may be deleted. Therefore, equation (2) becomes It becomes like this.

The term δkBs' must always take into account some disturbances. it's a hindrance This is because the matter is positive, thus reducing the output in the blanket.

In the past, the purpose of core design was usually to increase the durability of the seed, sb, and the seed. The durability of seeds is improved by placing more U-235 fuel in the seeds and absorbing the fuel to a higher level. as a result, the magnitude of δkBS′ is increased and the blanket The output part has been reduced.

Ordinary uranium blankets also have a larger macroabsorption than almost all Using a blanket whose body is thorium, we change the sign of our δkBS. This term has the opportunity to reduce the blanket output portion and thus also increases will let you.

Using (1-kB) in the denominator of the power sharing formula equal to 0.1 (kB is As mentioned above, it is about 0.9), a considerably small amount (about 0.3- A negative value of 0.5) indicates a large increase in the blanket output portion, i.e. PB/Ps. It can be added.

By using seeds with very low macroabsorption and high water-to-fuel ratio, we The direction of low energy flow from seed to blanket can be reversed . This is important for the ebithermal energy when U-233 forms. I'll go. The U-233 resonance absorption cross section is twice as large as the U-235 resonance absorption cross section. Moreover, the U-233 resonant splitting cross section is also very high.

Thus, there is a large reverse flow from the seed to the blanket, which is the blanket. Significantly improve the output part. Perform a blanket resonance capture line run We propose an increase in the number of thermal and ebithermal neutrons in the blanket without Seeds may be considered as multiplying reflectors for the provided blanket.

Heat flow between seeds and blanket Assuming constant geometry and heat flow, the heat flux is from the seed to the blanket. I'll go. and that using the symbols B and C for blankets and seeds, respectively. In each area.

(Deceleration source) S-person (heat absorption rate) s(6) (Deceleration source), +A-c heat absorption rate' ) B (7) (deceleration source) 8-φ, 5 vs ER8 (8) (heat absorption rate) S-φ2s vsΣ, 8(9) and a similar equation holds for the blanket.

Here, φ and φ2 indicate high velocity and heat flux, respectively.

■ is determined by the volume of the area・ ΣR is the deceleration cross section.

Σ is the macro absorption cross section.

d is a constant.

The bad thing is If we used a narrow strip of seed t-φ, ~φ , and therefore B becomes.

Note that if Vs is small, one person will also be small.

If Σ,8 is small compared to Σ1B.

Thus, if the right parenthesis is positive, then the left side is positive.

Use of thorium as a blanket , there is one fundamental difficulty. This is due to the formation of thorium U-233 inclusions. This means that the thorium blanket initially has an output of almost zero until the write Therefore, a small seed area cannot supply the core power with multiple occurrences, so Until the formation of Lancet U-233, the total power of the reactor core remained very low for several years. You'll end up having to sleep. However, it also forms thorium close to its equilibrium U-233 concentration. Too many neutrons are wasted to achieve this. The aforementioned 1964 The research of Genepa (G.N. Ma.) Report 1 (Fig. 2).

40.000 MWD/T The number of neutrons supplied from the This is several times larger than what should be needed based on the amount of U-233 remaining. It is shown that. The reason for this is that when the tJ-233 concentration is very low, %F thorium intermediate flux must be very high and therefore the neutron A large number is attributed to absorption in fissile material, cladding and water.

The two difficulties mentioned above are due to the presence of fissile fuel in the thorium at the beginning of the blanket life. Both can be avoided by providing a small amount of ffi. below For rounding reasons, it is necessary to keep the added uranium jl to a minimum. Ru.

1) In the case of fc using a material containing uranium of 10 tres or less.

Irradiation tests show that thorium oxide can withstand combustion exceeding 100,000 MWD/Tt. You can get it.

2) The smaller the amount of uranium, the higher the amount of uranium at high combustion. ,, Yes, it's expensive.

Therefore, the highest concentration of Kagishi (20chi) allowed from the consideration of non-weapons proliferation. It is preferable to use

The medium calculation in an infinite medium is (uniformly distributed in thorium oxide* U-235 (concentrated to about 10%), about 10% of uranium oxide has a very high combustion indicates that the blanket remains at about 0.9 through the blanket's high Combustion is first achieved through burning the U-233 produced in place. be done. U-238H from the first concentration of Plankesi, at the end of the blanket It is mixed uniformly with the remaining U-233, and as a result, U-233 is transformed into a weapon. can no longer be used for

Neutron losses to the control system are minimized with a Hasidic blanket core. can be done. In addition, the unique properties of thorium blankets are All part of the energy generated by the This will improve the utilization rate of uranium.

Brief description of the drawing The invention will be further explained below with reference to the accompanying drawings, which are shown by way of example only.

FIG. 1 is a sectional view of a light water reactor constructed according to the present invention.

Figure 2 illustrates one seed blanket module in the core of Figure 1. Ru.

Figure 3 illustrates the seed/fuel craft in Figure 2. .

FIG. 4 illustrates the blanket bundle in the core of FIG.

Figure 5 shows various types of blanket 71 (blanket irradiation versus fuel volume ratio). 2 illustrates the formation of a blanket multiplication factor with.

Figure 6 illustrates the formation of U-236 and U-234 in a thorium blanket. .

Figure 7 shows a pond seed that may be used for seed blanket moji, -k. -Illustrate the blanket cluster arrangement.

Figures 8 and 9 show a CAN-Dυ Tyg heavy water reactor constructed according to the present invention. Two types of arrangements that may be used are illustrated.

Figure 10 is Takano&! Figure 7. Description of preferred practical examples for light water composting furnaces. Light water reactor shown in Figures 1 to 8 As shown in detail in Part 1, the reactor is generally numbered 2 within the pressure vessel 4. The reactor core 2 includes a heat shield 6 and a core noxful 8. It's bent. The activated core 2 consists of a plurality of fuel modules 10, each of which This fuel module IO will be explained in detail based on FIGS. 2 to 4 below. A fuel that can be converted into fissile material by neutron capture, as shown in Contains a blanket region of parent material. The outer region 9 of the core 2 is a power leveling area. Oshi 5 example has similar composition as in the blanket area of module 10, but Concentration of about W when used in a blanket area of a module with low concentration, for example. It is dominated by multiple elements with uranium having .

Diagram M2 shows the seed blanket module in the activated core 2 shown in FIG. Each configuration of O is illustrated in more detail. Thus, as shown in Figure 2, Each of these modules has a central area surrounded by an annular seed area 14. The seed area 14 is conversely formed into an annular blanket area 16. Therefore, it is surrounded. Each of the aforementioned areas is similar to a completed module. It has a hexagonal outer contour. As previously pointed out, seed region 14 is fissile Each of the two blanket regions 12.16 is It has a fuel parent material that can be converted into fissile material. seed area An example of the configuration of the fuel elements in 14 is illustrated in FIG. ．． An example of a fuel element configuration in 16 is illustrated in FIG.

As illustrated in FIG. 3, the seed fuel element is in the form of a plurality of plates 20. . A plurality of such plates are mounted within each of the plurality of seed subassemblies 22. In the seed subassembly.

Between each pair of plates is a space or passage for a coolant/moderator made of water. (play) 20 are arranged at a distance t from each other to define the path. . The cross-sectional area of multiple seed fuel grates 2o and the cross-sectional area of the water passage between them are Determining the Fuel Volume Ratio As noted earlier, this ratio is determined by the blanket region 12. 16 is also substantially higher in the seed region 14; in the range of 3.0:1 to 9:1 in the blanket area and 0.8: in the blanket area Preferably, the ratio is within the range of 1 to 2.0:1.

The seed region 14 illustrated in FIG. 3 further defines control rod channels 26. and a spacer element 24 between each seed subassembly 22.

As shown in FIG. 4, within the blanket area 12 (and the bracket in FIG. The fuel zone material in the lanket area 16) is placed between the pair of end gray) 32.34 The mantissa is in the shape of a rod 3o.

The plurality of blanket fuel rods 30 provide space or passage for a coolant/moderator consisting of water. placed in spaced relationship to define a path.

In each of the two blanket regions 12.16 the water to fuel volume ratio is 1: It is good if it is 1. The fuel elements in these blanket regions are concentrated to 2° It may consist of a rod of thorium oxide with about 10% of fc uranium oxide. , these blanket areas are 100,000 MwD/T (Tunto Shimega Watts) It is designed to provide an average kB1c of approximately 0.9 per day). Blanke Items are not intended to be recycled and are simply discarded or otherwise placed in place.

Multiple grate forms of 20T enriched uranium coated in a zirconium alloy It is shaped like this. Seed fuel charging is for about 1 year at normal 70ch load rate. is designed to provide a multiplication factor (k'') in an infinite medium of 1.5. Because of the high thermal spectrum and low tJ-238 content of the sheet, the seed fuel Contains very little plutonium and therefore does not pose breeding problems can be played.

As an example, for a core of 1000 MJN*, 10 modules of 46 units and each module 10 has an inner blanket area of radius 283 and a radius of It has an outer blanket area of %α, thereby separating the inner blanket area and the outer Blanket area 7! I; Each constitutes about 40 inches of module volume, and the seed Area 14 constitutes approximately 20 inches of module area.

Figure 5 shows that thorium converts 10 t of bovine that was concentrated to 20 t in U-235. Figure 3 illustrates the properties of a containing thorium oxide blanket region. The above embodiment is 1:1 water-to-volume ratio and ≦20 thorium and uranium ratios in lankets /Ding (Tundang Shimegawatt) is used. Increase in MW/T is multiplication in infinite medium It is noted that this results in a decrease in the rate (k,,,'). This increases by 9 zo Based on RoF actinium. Also, Prankera F has a very hot 3:l water to fuel volume. For the ratio, the value of ktm is low, but may be less than that due to the increased absorption of water. It also attracts attention. This allows the blanket to be heated without adding more water to the blanket. Before the reversing heat flow that makes the blanket hotter does not reduce the heat in the blanket. substantiate the stated statement.

The sixth factor is for a water-to-fuel volume ratio of approximately 1.5 in these blanket regions. Figure 3 illustrates combustion of U-236 and U-234 within a thorium blanket region. we In the previous example of , this ratio is supposed to be 1.1, so this means that U - Increase the 234 ratio. U-238, which has a lot of material, and U-23, which has a lot of non-fissile material. 8. Initial state glue-235 to become U-236 and U-2 mixed with U-233 There are 34. In this way, if the final mixture can be exploded even a little. Otherwise, the final mixture must be dispersed in very large pieces. However, at that time U-233 The high degree of shielding required due to the high gamma activity of the bomb makes the bomb unfeasible.

Figure 7 illustrates another proposed module structure, which consists of two inner blanks. blanket area 40.42° seed area 44 and two outer blanket areas 46 ．． It has 48ffi. This modular structure is shaped like a hexagon-E as shown in FIG. -It may be called Joule's rectangular analogue. In Figure 7, the seed area material Inside the blanket area 40 contains 21 assemblies and 42 includes 24 assemblies, outside of the seed area 44, a blanket area 46. contains 40 assemblies and Prankella) area 48 contains 28 assemblies. .

Heavy water reactor (Figures 8 and 9) For illustrative purposes, the Kokonoe Water Reactor illustrated in Figures 8 and 9 is the Canadian water reactor. Can Do (C) at Douglas Point (Dougl&s Pof%) AN-DtJ) Factory design, or the basis for that design, 1962 NPD-2 (NPD (Canadian Nucl@ar　P ow@r　Demonstration)-2) Although it follows the design of the type nuclear reactor It is. Both reactors have a pressure of approximately 1150 seals per square inch as moderator and coolant. It is a pressure pipe that uses heavy water under pressure. The fuel consists of multiple chips of zirconium alloy. , normal uradine dioxide jacketed within a zirconium alloy supported within a It is nium. The coolant leaves the reactor at 277℃ (533 tubes) and is transferred to a heat exchanger for about 2 hours. Steam'5r at 30°C (446″F): Produced in the NPD-2 type reactor. has a gross power output of 22 MW with a thermal efficiency of approximately 25%, while CAN - The DU plant will produce more than 100 megawatts of power with approximately 25% thermal efficiency.

FIG. 8 schematically shows the core of such a nuclear reactor. The core is generally numbered 102. This tank contains a large tank or vessel called a calandria tube. A large number of double jacketed tubes 104 are penetrated. Each tube 104 has a Usually natural uranium or in some cases very slightly enriched uranium a cluster of a plurality of fuel rods 106 made from fissile material-containing elements that are nothing. This tank is filled with heavy water under normal pressure. It fills the space between 4 and serves as a moderator. This heavy water is basically remains at normal temperature. The tube 104 surrounding the plurality of fuel rods 106 is It is also heated under pressure of 500 to 1500 seals using heavy water as a coolant. The coolant flows between the inner wall of the double shut pipe 104 and the fuel rods 106. It flows through several circular passages.

Further details of the construction and operation of such reactors can be found in the published literature. readily available. Therefore, no explanation will be given here.

One application of the present invention is to maintain the current CAM-DU volume and easily refuel it. It is proposed to exchange elements. This is the case for each CAM-DU array. There are eight calandria tubes 104 arranged in a rectangular shape, excluding those placed at the boundaries. Similar seaweeds take advantage of the fact that they are surrounded by calandria tubes. This is done by using a de-blanket arrangement. @0 Calandria on the border Any tube 104 can be selected to serve as a "seed."

And the eight surrounding calandria tubes are used as a "blanket" be able to.

Thus, in the group of eight calandria tubes 104 illustrated in FIG. , the central tube 104S can be used as a seed. Doria tube 104b will serve as a blanket area for central tube 104S.

Inside each calandria tube is a fuel element divided into 3712 pieces.

configuration depending on whether they are used as seeds or blankets. Each fuel element has Thus, in the seed calandria tube 104S About 20% of the fuel is in zirconium and coated with zirconium alloy. It would be 4 or 615 volume percent (ma10) of enriched uranium, The fuel in the plastic/ketkaran Y rear pipe 104b was reduced by approximately 10 to 151 KIt. It will be thorium oxide containing about 10 parts of uranium oxide. all -F fuel elements are replaced and regenerated annually, while 1g of blanket fuel has approximately 100% ,000MwD/T combustion only replaced and eliminated every 10 years With the exception of It will be done.

FIG. 9 shows another module arrangement suitable for use in a heavy water reactor according to the present invention. Ru. Thus, in this module arrangement, 25% of the calandria tubes 204 These are one inner seed tube 204° seed tube 204t - surrounding 8 more Seed tube 204S.

It is composed of 16 blanket tubes 204b serving as seed tubes 204S.

Another possible application of the invention is in aqueous breeders. This application is illustrated in Figure 2. It is necessary to create a very closely packed lattice of hexagonal modules. cormorant. Seeds can be designed to provide reverse neutron flow. (proliferation that there is an increase in proliferation (as most of the and seed fuel charges are necessarily low, reducing the need for initial fissile fuel. This is an advantage.

Various variations are envisaged as described below.

1. Light water thorium blanket 2. Light water Cranicum blanket 3. 80 t heavy water glass 20 t light water thorium blanket 4,80-Heavy water glass 20% light water uranium blanket 5. Equipped with a double pellet blanket and then coolant on either side.

In all cases it is possible to utilize a unit module with an outer radius of 36 countries. The inner seed radius is 24α, and the annular seed extends from 24as to 27−. ing. The water to fuel volume ratio of the blanket will be approximately 0.3. Blanket The configuration should be as shown below.

1. Thorium oxide 2T U-233 B Depleted uranium oxide plus 4.5-plutonium oxide Plutonium is usually can be obtained by being discharged from the power station.

3. The above U-233 content in the thorium part and the above in the uranium part Double pellet blanket with geltonium @ The sea Y water to fuel volume ratio may be between 3:1 and 9:1. Seed fuel charging is shown in Figure 1. - The fuel charging may be the same as that described above for the light water reactor illustrated in FIG. other A variation is to use U-233 or geltonium seed combustion to obtain the same reactivity. It uses a feed charge.

Another possible application of the invention is in highly concentrated light water furnaces. In this application 1 The aim of using the reversed neutron flow according to the present invention is in a relatively small part of the core volume. In other words, it enables control of the reactor core from the seed area. On the other hand, a large amount of output is manufactured from a blanket area.

Figure 10 is a Ut-diagram of one type of module that is preferably used in such a nuclear reactor. Show. This module has a surrounding blanket area 304bk A small percentage of the total 6 product of the module 5 analogy is the percentage from 5 to 10%. The code region 304 S't- is included.

As an example, the seed region 304S can be cylindrical with a radius of 9σ. , the blanket region 304b is also formed into a cylindrical shape with a radius of 7t36sm. Can be done. The seed removal volume is 6.25% of the total volume including the blanket area. Become. In this application, the water to fuel volume ratio in seed region 304S is approximately 4 = 1, and the fuel charge is zirconium with a zirconium alloy coating. 3 vlo of highly enriched uranium (93% U-235) in -St) Te is good to have.

The fuel in the blanket region is 25mm 10 hafnium and 50mm 10 zirconium. 25 muffs of highly enriched uranium oxide in the alloy of aluminum. in blanket The water to fuel volume ratio may be about 0.9:1. The aim is to reverse the neutron heat flow to a very high The objective is to provide high resonance capture in the blanket such that it is effective.

Combustible poisonous substances have a multiplication factor (ko) of 2 in an infinite medium during blanket operation. To maintain approximately 0.4 and maintain a flat power distribution through the blanket will be used for. Preferably about 2% of the core power comes from the seed region. Since the ib part of the core is subcritical, the seed region controls the core. Keep rolling.

Obviously, there are many other variations, modifications and applications of the invention.

FIG.7 FIG.9

Claims (17)

[Claims] 1. comprising a seed region and a blanket region, the seed region being a fissile material. a thermal neutron atom in which the blanket region contains a fuel parent substance; In the child furnace, the seed region and the blanket region are separated from the seed region by the blanket region. heat absorption characterized by the presence of a net flow of thermal neutrons into the ket region Sex nuclear reactor. 2. The blanket region has a larger ratio of macro heat absorption cross sections than the seed region A nuclear reactor according to claim 1. 3. Claim 2 in which light water is used as a coolant and moderator in the seed zone Nuclear reactor described in section. 4. Claims where light water is used as a coolant and moderator in the blanket region The nuclear reactor described in box 3. 5. Claims wherein the water to fuel volume ratio in the seed is in the range of 10:1 to 5:1. Nuclear reactor according to paragraph 4. 6. The water to fuel volume ratio in the blanket ranges from 0.8:1 to 2.0:1. A nuclear reactor according to claim 4. 7. The water to fuel volume ratio in the seed is substantially 9:1 and the water in the blanket is 5. The nuclear reactor of claim 4, wherein the fuel to volume ratio is substantially 1:1. 8. Seed macro heat absorption kept low by using 20% enriched uranium 2. The nuclear reactor of claim 1, wherein the nuclear reactor is non-breeding. 9. The multiplication factor (kS) of the seed in an infinite medium is 1.3 to 1.5, and the blank The multiplication factor (kB) of the ket in an infinite medium is substantially 0.9. The nuclear reactor described in item 1. 10. The source according to claim 1, wherein the seed volume is 15 to 255% of the core volume. Child furnace. 11. A nuclear reactor according to claim 1, wherein the blanket region comprises thorium. . 12. 12. A nuclear reactor according to claim 11, wherein the thorium is enriched with fissile material. 13. The blanket contains 12▼/0 uranium enriched to 20▼/0 uranium 235. 13. A nuclear reactor according to claim 12, comprising thorium containing up to ranium. 14. The reactor extends through a plurality of calandria tubes, each having a fuel rod. A heavy water nuclear reactor that includes a large tank with air passing through it, and the tank has atmospheric air. It is essentially filled with heavy water under pressure and serves as a moderator, causing calandria The tubes are filled with pressurized heavy water to serve as a coolant and to The fuel in at least one of the Doria tubes includes fissile material to define the seed region. and the fuel in at least one other of the plurality of calandria tubes is a fuel parent substance. defined in claim 1 and defining said blanket area. nuclear reactor. 15. Claims where the heavy water moderator is beryllium, graphite or a combination thereof. The nuclear reactor described in item 14. 16. The seed region contains highly enriched uranium and is a relatively small portion of the core volume. Occupies 5-10% of the total core volume to enable core control from A nuclear reactor according to claim 1, which includes: 17. Blanket areas closely packed lattice to provide growth potential A nuclear reactor according to claim 1, comprising: