KR20010095996A - Plate Type Fuel Based - Low Power Medical Reactor for Boron Neutron Capture Therapy - Google Patents

Abstract

PURPOSE: A low output boron neutron capture cancer treatment nuclear reactor is provided to obtain a high epithermal neutron in an efficient manner and maintain minimum core size by using a plate type nuclear fuel. CONSTITUTION: A nuclear reactor for radiating beam to the tumor area of the patient, and removing tumor cells in a safe manner, comprises a nuclear reactor core having a plate type collection(10) formed of an array of twelve plates(3X4) so as to cause nuclear fission and generate neutron, and a control plate arranged to two central plates of the plate type collection so as to assist nuclear reactor stopping operation; and a beam collimator(20) for reducing the high speed neutron into epithermal neutron, and radiating the epithermal neutron to the tumor area of the patient. The beam collimator is arranged in four directions from the center of the nuclear reactor, and constituted by an aluminum fluoride layer(21), an aluminum layer(22), a titanium layer(23), a cadmium plate(24) and a bithmuth layer(25).

Description

Plate Type Fuel Based-Low Power Medical Reactor for Boron Neutron Capture Therapy}

TECHNICAL FIELD The present invention relates to a nuclear reactor for treating boron neutron capture cancer, and in particular, to a nuclear reactor for cancer treatment that can efficiently provide high thermo-neutrons from a very small core by using plate fuel.

Gliomas, which have been the main targets for treatment of neutron capture cancer, are caused by the transformation of glial cells into cancer cells. Because glioma rarely metastasizes to organs other than the brain and accounts for about 80% of all malignant cancers and still no effective treatment, boron neutron capture cancer treatment has been applied mainly to brain cancer. In the case of glioma, especially the boron compound is well collected in cancer cells. If the pre-injected boron compound gathers only around the brain cells without cutting the head bone, the neutron beam is split into the area, and alpha rays and lithium are generated from the nuclear reaction between neutrons and boron. It is an effective way to kill only cancer cells due to the energy of atoms.

To do this, unlike neutrons from nuclear power plants, it is necessary to obtain specialized neutrons for cancer treatment. Specialized neutrons are extraneous neutrons that are free from contamination by other gamma rays or high-speed neutrons as long as they do not affect normal cells. . Obtaining sufficient heat neutrons can shorten the psychological and economic burden of patients who need to be fixed because they are irradiated to cancer cells in a short time, as well as reduce the time to spread boron compounds to normal cells, thereby increasing the therapeutic effect. . However, most of all, it is the most important way to safely obtain high thermoneutral neutrons to be able to penetrate the head bones deeply, such as brain cancer or large tumor size.

Major neutron generators include nuclear reactors, accelerators, and actinide elements, but to date, only nuclear reactors have been proved to be applicable to the treatment of actual patients through clinical trials. Indeed, treatment with reactors is actively underway. However, cancer treatment in these countries is mainly made by modifying existing reactors, so it is difficult to obtain strong neutrons, and there is a limit because treatment cannot be performed in connection with hospitals. Therapeutic reactors are inevitable, especially in developing countries without research reactors.

In addition, although the technology for the polygonal reactor for the treatment of boron neutron capture cancer conventionally designed for cancer treatment is described in Korean Patent No. 241231, the installation of heavy water in the center of the core and the installation of 1056 rod-type nuclear fuels in the core Given the fact that the reactors are established near hospitals in densely populated areas, there are significant disadvantages in the safety management and operation of the reactor construction and operation. First and foremost, a single neutron irradiation within a few minutes, which is the main reason for installing a dedicated reactor, does not provide 1.0x10 ¹⁰ n _ep / cm 2 sec thermoneutral neutrons necessary for treatment.

Therefore, the present inventors change the fuel material and fuel shape, the shape of the core, the moderator of the beam collimator, the range of neutron use, etc. to improve these points, while making the nuclear reactor core of the smallest size, while deeply existing brain cancer and a large tumor In order to specialize in the treatment, the company has designed a reactor that maximizes the use of strong thermoneutrons.

Therefore, the present invention has been made to solve the problems of the prior art as described above, while maximizing the use of neutrons coming from a low-power reactor while coming out through nuclear fission using nuclear fuel plate having a large area and relatively thin thickness Most of the neutrons are used for the purpose of treatment, and the purpose is to provide a reactor capable of maintaining high core neutrons as well as maintaining a minimum core size.

1 is a plan view of a conventional plate-shaped fuel assembly,

Figure 2 is a plan view of a plate-shaped control panel assembly informing the position of the six control panels in normal operation according to the present invention,

3 is a plan view of a plate-shaped control panel assembly driven by four stop control panels when the reactor is stopped according to the present invention;

4 and 5 are a plan view and a side view of the reactor when the slab reactor core (3 × 4 assembly) and the beam shutter are opened according to one embodiment of the present invention;

FIG. 6 is a detailed side view of the reactor shown in FIG. 5;

7 is a side view when the beam shutter of the reactor shown in 5 is closed;

8 is a plan view of a nuclear reactor when the beam shutters are closed in all four areas according to the present invention.

♠ Explanation of symbols on the main parts of the drawing ♠

10: aggregate 11, 14: hard water

12, 15, 16: nuclear fuel plate 13: cadmium control panel

20 beam collimator 21 aluminum fluoride layer

22: aluminum layer 23: titanium layer

24: cadmium sheet 25: bismuth layer

26: opening portion 27: concrete wall

28 nickel plate 29 iron shutter

30: lead layer

According to the present invention for achieving the above object, in a nuclear reactor that emits neutrons that can selectively and locally remove only the tumor cells by irradiating the tumor site of the patient, plate-like to generate neutrons while causing nuclear fission Twelve aggregates are arranged in the form of 3 x 4, and the central two plate aggregates include a nuclear reactor core containing a control panel for stopping the reactor; A nuclear reactor including a beam collimator for irradiating a tumor site of a patient by decelerating a high speed neutron generated by the reactor core into an external neutron is provided.

In addition, according to the present invention, the two plate-shaped aggregates are filled with hard water so that the control panel necessary for stopping the reactor is inserted in six centers, and the six left and right sides have a wide area and a thin thickness to create a large amount of neutrons. It is preferable that it is a control panel assembly in which the plate-shaped nuclear fuel plate which has is inserted, respectively.

In addition, according to the present invention, it is preferable that the ten plate-shaped aggregates positioned at the outer side of the plate-shaped aggregates are nuclear fuel assemblies in which 18 plate-shaped nuclear fuel plates having a large area and a thin thickness are inserted to produce a large amount of neutrons.

In addition, according to the present invention, the nuclear fuel used in the plate-like nuclear fuel plate is preferably low concentration uranium silicaide (U ₃ Si ₂ -A | 4.8g U / cc).

In addition, according to the present invention, the beam collimator is formed in four directions in the north-west, north-west direction at the center of the reactor, and the inner side of the plate-shaped aggregate located in the center of the aluminum fluoride layer, aluminum layer, titanium layer, cadmium sheet and It is preferable that it is comprised from the bismuth layer in which the opening part was formed.

In addition, according to the present invention, it is preferable that the beam collimator is formed to become smaller from the inner side to the outer side of the center.

In the following, a preferred embodiment of the reactor according to the present invention will be described in detail with reference to the accompanying drawings.

Figure 2 is a plan view of a plate-shaped control panel assembly for indicating the position of the six control panels in normal operation according to the present invention, Figure 3 is a planar control panel assembly driven by the four stop control panel when the reactor stops according to the present invention Top view. 4 and 5 are a plan view and a side view of the reactor when the slab reactor core (3 × 4 assembly) and the beam shutter are opened according to an embodiment of the present invention, and FIG. 6 is a view of the reactor shown in FIG. Detailed side view. 7 is a side view when the beam shutter of the reactor shown in FIG. 5 is closed, and FIG. 8 is a plan view of the reactor when the beam shutters are closed in all four areas according to the present invention.

The reactor according to the present invention has a total size of about 214 cm (W) x 214 cm (W) x 260 cm (H), and is 23.46 cm (W) x 31.28 cm (W) x 64.8 cm (H) in the center of the cuboid. The shim is located. In other words, the reactor of the present invention is composed of a reactor core and a beam collimator in the direction perpendicular to the core direction, that is, east-west-south-north-type as shown in FIG. 4, and the rest of the reactor core is filled with concrete.

In addition, the reactor of the present invention allows the cooling water to flow from the bottom of the reactor core to the top, and the core of the reactor forms 12 (horizontal) × 4 (vertical) shapes in which twelve plate assemblies 10 form neutrons while causing fission. Are arranged as: At this time, the two aggregates located at the center are filled with hard water so that the control panel necessary for the reactor stops. That is, in normal operation, these two aggregates are filled with hard water 11 in six places, nuclear fuel plate 12 is inserted in twelve places, and in reactor shutdown, four are shown in FIG. The cadmium control panel (13) is inserted in two places, the hard water (14) is filled in two places, and the control panel assembly in which the nuclear fuel plate (15) is inserted is inserted in twelve places. In addition, hard water flows between the fuel plate and the control panel.

In addition, the remaining 10 assemblies have been proved to be capable of processing and use the plate fuels currently used in research furnaces. That is, as shown in FIG. 1, fuel assemblies including 18 nuclear fuel plates 16 are inserted into 10 aggregates. In the assembly 10 constructed as described above, a total of 204 nuclear fuel plates are inserted.

The nuclear fuel plate used in the present invention is composed of 0.051 cm (width) x 6.1 cm (length) x 63.8 cm (height) of nuclear fuel and a 0.038 cm thick aluminum cladding covering the nuclear fuel. It is loaded to look west. The fuel is low-enriched uranium silicate (U ₃ Si ₂ -A | 4.8 g U / cc).

In addition, a part of a total of 12 control panels is inserted into two assemblies located at the center of the assembly 10 to shut down the reactor. As a result of calculating using the MCNP computer code, eight of the 12 control panels (per control panel assembly) Only four are inserted in normal control and the other four are inserted and used in emergency control. Each control panel is a nuclear fuel plate-like structure, but designed to contain cadmium at the location of the fuel.

In addition, the beam collimator 20 is made of an arrangement and an entire structure of the material so as to form a strong thermo neutron, and a detailed arrangement relationship thereof will be described with reference to FIGS. 4 to 8 and Table 1 as follows.

Table 1 shows the media according to the distance from the direction of each beam from the center of the reactor toward the east and north.

Distance (cm) Characteristic Medium East-West-11.73-11.7311.73-49.2349.23-86.7386.73-88.2388.23-88.2888.28-95.7895.78-105.78 North-south-15.64-15.6415.64-50.2350.23-88.2388.23 -89.7389.73-89.7889.78-96.2896.28-106.28 Pass through core reflector and filter filter and deceleration filter and deceleration cadmium film gamma ray shielding beam Pass through core reflector and filter filter and deceleration filter and deceleration cadmium film gamma ray shielding beam U ₃ Si ₂ -Al and H ₂ OAlF ₃ AlTiCdBi air U ₃ Si ₂ -Al and H ₂ OAlF ₃ AlTiCdBi air

That is, the beam collimator 20 is formed in four directions from the center of the nuclear reactor in the east, south, west, north, and south directions, and the aluminum fluoride layer (21; 37.5 cm) and the aluminum layer (22) outward from the inside of the assembly 10 located at the center. 37.5 cm), a titanium layer (23; 1.5 cm), a cadmium thin plate (24; 0.05 cm), and a bismuth layer (25; 7.5 cm) formed with the opening portion 26 are sequentially formed. At this time, the components are sequentially reduced in size from the nuclear fuel plate is configured so that the opening portion 26 directly projected to the patient's head is a square of 20cm x 20cm. And the nickel plate 28 is formed in the side surface of the aluminum fluoride layer 21, ie, the site | part which contacts the concrete wall 27. As shown in FIG.

The aluminum fluoride layer 21, the aluminum layer 22, and the titanium layer 23 shield high-speed high-energy neutrons from neutrons released during nuclear fission (reflection, filter, and deceleration), and the cadmium thin plate 24 is relatively low. Shields thermal neutrons with energy In addition, the bismuth layer 26 shields gamma rays generated during nuclear fission, and the concrete wall 27 is used to prevent radiation leakage. Therefore, only the neutrons out of the neutrons generated during nuclear fission are selectively radiated to the opening portion 26. At this time, the extraneous neutron radiated to the opening portion 26 is suitable for the treatment of tumor cells existing in the body of the patient with an energy of 0.4 eV < E < 10 KeV.

In the figure, reference numeral 29 denotes an iron shutter containing boron compound, and 30 denotes a lead layer used to prevent radiation leakage. Here, the iron shutter 29 is lifted upwards as shown in FIGS. 5 and 6 during the experiment or treatment of the patient so that the required external neutrons are radiated to the opening portion 26 of the beam collimator 20. However, during the preparation of the experiment, treatment of the patient or abnormal operation of the reactor, as shown in Figures 7 and 8 to lower down to prevent the external neutron radiated to the outside.

Table 2 below is a comparison table in which the inventors compared and evaluated the radioactivity of the thermal neutrons with respect to the conventional reactor and the reactor according to the present invention.

That is, Table 2 shows Brookhaven Medical Research Reactor (BMRR), Massachusetts Institute of Technology's Research Reactor (USA), Petten (Petten High Flux Reactor (Netherlands)), Musashi (Musashi Institute of Technology's Reactor (Japan)), and conventional examples. A conventional reactor such as Korean Patent No. 241231 and the reactor of the present invention having the specifications as described above were compared and evaluated.

And, in Table 2 below, the numerical values given in each item is a result of the probabilistic calculation method using the Monte Carlo sampling, and the numerical values in Table 2 is a nuclear reactor because it is presented for a rough comparison with conventional reactors. Resizing the core and beam collimator can give better results.

Atomically Power (MW) φ _epi × 10 ⁹ / cm ² D _n / n _epi × 10 ^-13 Gycm ² / n D _γ / n _epi × 10 ^-13 Gycm ² / n J / φ φ / Power BMRRMITRPetten Patent No. 241231 The present invention (East-West) The present invention (North-South) 354.50.30.30.3 2.70.20.333.216.7 ^a 12.9 ^d 4.31310.41.572.2 ^b 3.0 ^e 1.0148.4 <1.01.4 ^c 2.0 ^f 0.670.55 ＞ 0.80.740.650.66 0.90.040.007310.655.743

In Table 2, φ _epi denotes a thermo neutron flux, D _n / n _epi denotes a fast neutron emission amount with respect to the thermal neutron emission amount, and D _γ / n _epi denotes the emission amount of γ-rays to the emission amount of the thermal neutron. Where J / φ represents the orientation of nuclear fission particles or their collecting speed, and finally Power represents the calorific value of the reactor core or its required power. In Table 2, a represents an error limit of 1%, b represents an error limit of 7%, c represents an error limit of 8%, d represents an error limit of 0.8%, e represents an error limit of 5%, and f represents an error limit of 7%, respectively. Here, the flux and emission amount of the neutron are calculated for the neutron beam irradiated directly to the end of the beam collimator, that is, the affected part.

That is, as can be seen in Table 2, since the extraneous neutron flux of the present invention was generated up to 5 times more than the conventional designed reactor (see φ / Power), the same extraneous neutron was obtained to obtain about 1/5 of the conventional reactor. It can be operated sufficiently as a power source (see Power).

Table 3 shows the results of verifying the critical probability of the reactor of the present invention, which is the evaluation target of Table 2, using the MCNP computer code according to the number of fuel plates, the presence or absence of the control panel, and the opening and closing of the steel shutter.

The number of nuclear fuel plates Control panel (12) Iron Shutter Criticality (K _eff ) 204204204204204204 UpUpDown (8 only) Down (8 only) All Down (Emergency) All Down (Emergency) OpenClosedOpenClosedOpenClosed 1.04909 ± 0.000861.04986 ± 0.000880.94806 ± 0.000860.94705 ± 0.000920.92687 ± 0.000880.92809 ± 0.00084

As can be seen in Table 3, when the reactor is configured as in the present invention, it can be seen that stability is ensured even during normal operation or stop.

As described in detail above, the reactor of the present invention has a very high ratio of the extraneous neutrons to the output compared to the low output (see Table 2). Can be reduced.

In addition, according to the present invention, four additional safety control panels for emergency stop can be obtained to obtain four stop margins (see Table 3).

In addition, the present invention can obtain a high external neutron on all four sides of the slab core, can treat four patients at the same time, there is a room to adjust the intensity and direction of the beam according to the type of cancer.

In addition, the present invention by designing the 3 x 4 aggregates to ensure stability and to minimize the size of the core of the reactor, as well as to obtain a high thermal neutron from all four sides to maximize the use.

In addition, in the present invention, since the size thereof is about 2m in length and width (see Table 1), it is possible to reduce construction costs, building maintenance costs, etc. in selecting a site.

In the above description of the technical details of the reactor of the present invention with reference to the accompanying drawings, which illustrate the best embodiment of the present invention by way of example and not limit the present invention.

In addition, it is obvious that any person skilled in the art can make various modifications and imitations without departing from the scope of the technical idea of the present invention.

Claims (6)

In a reactor that emits neutrons that can be irradiated to a tumor site of a patient to selectively and locally remove only those tumor cells, Twelve plate assemblies are arranged in the form of 3 x 4 so as to generate neutrons while generating fission, and two central plate assemblies have a nuclear reactor core containing a control panel for stopping the reactor; And a beam collimator for irradiating the tumor site of the patient by decelerating the high speed neutron generated by the reactor core into an external neutron. According to claim 1, wherein the two plate-shaped assembly is filled with hard water so that the control panel necessary for stopping the reactor is inserted in the six places in the center, the left and right six places having a large area and a thin thickness to create a large amount of neutrons A nuclear reactor characterized in that the plate-like fuel plate is inserted into each control panel assembly. The nuclear reactor assembly of claim 1, wherein the ten plate assemblies located at the outer side of the plate assemblies are fuel assemblies in which 18 plate-shaped fuel plates having a large area and a thin thickness are inserted to generate a large amount of neutrons. The reactor according to claim 2 or 3, wherein the nuclear fuel used for the plate-shaped nuclear fuel plate is low concentration of uranium silicaide (U ₃ Si ₂ -A | 4.8 g U / cc). According to claim 2 or 3, wherein the beam collimator is formed in four directions in the north-west, north-west direction at the center of the reactor, and the inner side of the plate-shaped assembly located in the center of the aluminum fluoride layer, aluminum layer, titanium layer, A reactor comprising a bismuth layer in which a cadmium thin plate and an opening portion are formed. The reactor of claim 5, wherein the beam collimator is formed to become smaller from the inner side to the outer side of the center.