阅读说明：本技术 一种基于商业压水堆辐照靶件生产放射性同位素的方法 (Method for producing radioactive isotope based on commercial pressurized water reactor irradiation target ) 是由 王帅 唐霄 刘晓黎 李满仓 于颖锐 汪量子 肖鹏 王丹 沈云海 谢运利 蒋朱敏 于 2020-08-12 设计创作，主要内容包括：本发明公开了一种基于商业压水堆辐照靶件生产放射性同位素的方法,利用商业压水堆辐照靶件生产放射性同位素；具体地,利用商业压水堆辐照靶件生产放射性同位素的操作包括以下步骤：S1.在商业压水反应堆停堆期间,将辐照靶件安装在燃料组件的导向管中；S2.辐照靶件随燃料组件进入堆芯辐照,在堆内中子场环境下发生反应产生目标放射性同位素；S3.反应堆再次停堆后,取出辐照靶件,提取目标放射性同位素。该技术的应用为放射性同位素的生产提供了新的方法,也可更为充分地利用压水反应堆内的中子场环境,提高其经济性能。(The invention discloses a method for producing radioactive isotopes based on commercial pressurized water reactor irradiation target pieces, which comprises the steps of producing the radioactive isotopes by using the commercial pressurized water reactor irradiation target pieces; specifically, the operation of producing radioisotopes using commercial pressurized water reactor irradiation targets includes the steps of: s1, installing an irradiation target in a guide pipe of a fuel assembly during shutdown of a commercial pressurized water reactor; s2, allowing the irradiation target piece to enter a reactor core along with the fuel assembly for irradiation, and reacting in a neutron field environment in the reactor to generate a target radioisotope; and S3, after the reactor is stopped again, taking out the irradiation target piece, and extracting the target radioisotope. The application of the technology provides a new method for producing the radioactive isotope, and can also more fully utilize the neutron field environment in the pressurized water reactor and improve the economic performance of the pressurized water reactor.)

1. A method for producing radioisotopes based on commercial pressurized water reactors, wherein the operation of producing radioisotopes using a commercial pressurized water reactor irradiation target comprises the steps of:

s1, directly installing a bare irradiation target in a guide pipe of a fuel assembly during shutdown of a commercial pressurized water reactor;

s2, allowing the irradiation target piece to enter a reactor core along with the fuel assembly for irradiation, and reacting in a neutron field environment in the reactor to generate a target radioisotope;

and S3, after the reactor is stopped again, taking out the irradiation target piece, and extracting the target radioisotope.

2. The method for producing radioisotopes based on commercial pressurized water reactor according to claim 1, wherein in step S1, the irradiation target is placed in place of a choke plug assembly in a guide tube or in an empty guide tube.

3. The method for producing radioisotopes based on commercial PWR irradiation target according to claim 1, wherein in S1, the guiding tubes for placing the irradiation target have a symmetric relationship in the fuel assembly, and are mirror symmetric with respect to the diagonal of the fuel assembly.

4. The method for producing radioisotopes based on the commercial PWR irradiation target according to claim 1, wherein in S1, the irradiation target is placed close to the axial midplane of the fuel rods.

5. The method of claim 1, wherein the fuel assemblies for placing the target are symmetrical in the core and mirror-symmetrical with respect to a diagonal of the core in S2.

6. The method for producing radioisotopes based on commercial PWR irradiation targets of claim 1, wherein in S2, the fuel assemblies on which the targets are placed are radially close to the center of the core.

7. The method for producing radioisotopes based on commercial PWR irradiation target according to any one of claims 1 to 6, wherein the commercial PWR uses fuel assemblies that are square or hexagonal.

8. The method for producing radioisotopes based on the commercial PWR irradiation target according to claim 7, wherein the number of fuel assemblies in the commercial PWR is one of 10-200.

9. The method for producing radioisotopes based on the commercial PWR irradiation target according to any one of claims 1 to 6, wherein the irradiation target is solid and has a shape comprising one of a plate, a block, a cylinder or a ring.

10. The method for producing radioisotopes based on commercial PWR irradiation target according to any one of claims 1 to 6, wherein the main component A of the irradiation target is in a gaseous or liquid state.

11. The method for producing radioisotopes based on commercial pressurized water reactor irradiation target according to any one of claims 1 to 6, wherein the irradiation target has a main component A which is a compound; the compound comprises F in the component^-，O^2-，O₂ ^4-，O₃ ^6-，CO₃ ^2-，SO₃ ^2-，SiO₃ ^2-，NO₃ ^-，N₃ ^-Or N₂ ^6-One kind of (1).

12. According toThe method for producing radioisotopes according to any one of claims 11, wherein the irradiation target comprises a major component a comprising AlN and Be₃N₂、SrCO₃、Y₂O₃、Gd₂O₃、Sm₂O₃、TeO₂Gas sum AmO₂One kind of (1).

13. The method for producing radioisotopes based on commercial PWR irradiation target according to any one of claims 1 to 6, wherein the irradiation target has a main component A comprising a simple substance²⁰⁹Bi、⁹⁸Mo、³¹P、¹⁸⁵Re、⁶²Ni、Co、⁷⁴Se, tin wire,¹²⁴Xe gas,¹⁷⁶Lu、¹⁷⁶Yb、¹⁸⁶W、²³⁵U、¹⁹¹Ir、²²⁶Ra、¹¹²Sn and distillatively purified sulfur.

Technical Field

The invention relates to the technical field of nuclear reactors, in particular to a method for producing radioactive isotopes based on a commercial pressurized water reactor irradiation target.

Background

The main production modes of the prior radioactive isotopes comprise nuclear reactor production, accelerator production, chemical separation, electromagnetic enrichment and purification. In the production of nuclear reactors, research reactors or production reactors are mainly used for production instead of commercial pressurized water reactors. When a reactor irradiation target is researched to produce radioactive isotopes, the target corresponding to target nuclides is placed into a specific irradiation pore channel in a reactor, and the target nuclides are generated through some nuclear reactions after irradiation for a certain time in a neutron field in the reactor. Is most widely used globally^99mTc is taken as an example of the reaction,^99mtc is the most widely used medical imaging radionuclide worldwide, accounting for up to 80% of the worldwide nuclear medicine radioisotopes. The nuclide now mainly passes through⁹⁹Decay of Mo. Since both nuclides have short half-lives and cannot be stored for a long time, they must be regularly produced and sent to a medical imaging center. Almost all of the current worldwide for medical use⁹⁹Mo is produced by adopting a mode of irradiating a high-concentration uranium target in a research reactor according to the principle²³⁵U(n，f)⁹⁹And Mo. By 2016, 6 months, 95% of the global medical use⁹⁹Mo came from 7 research stacks located in australia, canada, europe and south africa respectively and 5 target processing facilities located at the same site as part of the research stacks.

The use of research or production reactors to produce isotopes has the disadvantage of requiring a dedicated design to build the reactor and associated support personnel and facilities, with significant capital investment.

Commercial pressurized water reactors utilize pressurized light water as a reactor coolant and moderator to convert the thermal energy generated by nuclear fission into electrical energy for human use. The commercial pressurized water reactor core mainly comprises fuel assemblies, and the fuel assemblies generally comprise structures such as fuel rods, guide pipes, instrument pipes, spacer grids and the like. The fuel rods mainly contain fuel components required for maintaining fission reaction, and in-pile probes can be placed in the instrument tube cells. Control rods, burnable poison rods or neutron source assemblies may be placed as desired in the guide tubes, while for empty guide tubes not loaded with such assemblies, choke plug assemblies are inserted to avoid coolant bypass flow.

When the commercial pressurized water reactor is operated under the designed power, neutrons in the reactor are continuously generated and disappeared, and a stable neutron field environment is maintained. Taking a conventional M310 type commercial pressurized water reactor as an example, when the reactor is operated at full power, the average thermal neutron (E is less than or equal to 0.625eV) flux density in a fuel assembly in the reactor can reach 10¹³n/cm^-2·s^-1The flux density of fast neutrons (E > 0.625eV) can reach 10¹⁴n/cm^-2·s^-1Magnitude. There is some difference in specific neutron flux densities at different locations within the fuel assembly, but the basic magnitudes are the same.

The isotope production by using the commercial pressurized water reactor can fully utilize the existing reactor facilities, provide radioactive isotope while outputting electric energy, and improve the economy of the commercial pressurized water reactor.

According to the research of the inventor, some of the patents related to the production of radioactive isotopes by irradiation of commercial pressurized water reactors include:

1) patent "radionuclide generation system and method for producing radionuclide" published in 2019, 6/11 (CN 109874296). In this patent, radioisotopes are produced by irradiating target pieces, including irradiation targets and virtual targets, with instrumentation tube channels of a nuclear reactor fuel assembly.

2) A patent published in 2019, 1 month and 22 days, namely a system for producing medical short-life radioactive sources by using a pressurized water reactor nuclear power station (CN 106128539). In the patent, a set of reactor core irradiation subsystem is used for completing operations of feeding irradiation target articles into a reactor core, irradiating and removing the irradiation target articles out of the reactor core, and the irradiation position is also positioned in a fuel assembly instrument tube.

3) A patent published on 19.1.2016 OF METHODs OF PRODUCING isotops IN powerneclear waters (translation: method for producing isotopes by nuclear reactor) (US9239385B 2). In this patent, it is known to place irradiation targets in nuclear power plant reactor fuel assembly instrumentation tubes (instrumentation tubes) to produce radioisotopes.

The above patents still have disadvantages: both patents 1) and 2) require additional target in-and-out systems in the reactor structure, which may adversely affect commercial pressurized water reactor operation. For some radioisotopes with longer half-lives or lower irradiation yields, the desired yield may be achieved after a long irradiation period, and the target need not be moved after it is placed in the core, so the target removal systems of the 1) and 2) patents are not practical. The patents 1), 2) and 3) all place the target in the instrumentation tubes (instrumentation tubes) of the fuel assemblies, but the number of the instrumentation tubes in the reactor core is not large, each fuel assembly box only has 1, neutron detectors, thermocouples and the like are partially needed to be placed, the instrumentation tubes actually used for placing the irradiation target are limited, and the yield of the radioactive isotope is directly influenced.

Disclosure of Invention

Aiming at the technical problems, the invention provides a method for producing radioactive isotopes based on a commercial pressurized water reactor irradiation target, which solves the problems, the target is directly placed into a guide pipe, an additional target moving-in/moving-out system is not required to be specially arranged, the practicability is strong, and the method is particularly suitable for radioactive isotopes with longer half-life periods or lower irradiation yield; the target piece is placed in the guide tube, so that the selection range of the placement position of the target piece is increased, and the yield of the radioactive isotope is improved.

The invention is realized by the following technical scheme:

a method for producing radioactive isotopes based on commercial pressurized water reactor irradiation target parts comprises the following steps:

s1, installing an irradiation target in a guide pipe of a fuel assembly during shutdown of a commercial pressurized water reactor;

s2, allowing the irradiation target piece to enter a reactor core along with the fuel assembly for irradiation, and reacting in a neutron field environment in the reactor to generate a target radioisotope;

and S3, after the reactor is stopped again, taking out the irradiation target piece, and extracting the target radioisotope.

In the invention, the irradiation target is placed in the fuel assembly guide pipe, so that irradiation resources in the reactor can be effectively utilized; moreover, in the fuel assembly, the number of the guide pipes is large (for example, a single AFA3G assembly comprises 24 guide pipes), and the arrangement position of the irradiation target is flexible. The target is directly placed into the guide tube, an additional target moving-in/moving-out system is not required to be specially arranged, the practicability is high, and the device is particularly suitable for radioactive isotopes with long half-life periods or low irradiation yield;

the invention provides a method for producing radioactive isotopes by using commercial pressurized water reactor irradiation target members, provides a new method for producing the radioactive isotopes, and can also more fully utilize the neutron field environment in a pressurized water reactor to improve the economic performance of the pressurized water reactor.

Further preferably, in step S1, the irradiation target replaces a choke plug assembly in the guide tube or is placed in an empty guide tube.

Further preferably, in S1, the guide tubes for placing the irradiation targets have a symmetrical relationship in the fuel assembly, and have mirror symmetry with respect to the diagonal of the fuel assembly.

Further preferably, in S1, the irradiation target is placed near the axial midplane of the fuel rod.

Further preferably, in S2, the fuel assemblies on which the targets are placed have a symmetrical relationship within the core, and are mirror-symmetrical with respect to a diagonal of the core.

Further preferably, in S2, the fuel assembly on which the target is placed is located radially close to the center of the core.

Further preferably, the fuel assemblies used in the commercial pressurized water reactor are square or hexagonal.

Further preferably, the commercial pressurized water reactor comprises: one of a commercial pressurized water reactor consisting of 157 square fuel assemblies, a commercial pressurized water reactor consisting of 121 square fuel assemblies, a commercial pressurized water reactor consisting of 177 square fuel assemblies, a commercial pressurized water reactor consisting of 193 square fuel assemblies, and a commercial pressurized water reactor consisting of 163 hexagonal fuel assemblies.

Further preferably, the irradiation target is a solid, and the shape includes one of a plate shape, a block shape, a cylindrical shape, and a circular ring shape.

Further preferably, the main component a of the irradiation target is in a gaseous state or a liquid state.

Further preferably, the main component A of the irradiation target is a compound; the compound comprises F in the component^-，O^2-，O₂ ^4-，O₃ ^6-，CO₃ ^2-，SO₃ ^2-，SiO₃ ^2-，NO₃ ^-，N₃ ^-Or N₂ ^6-One kind of (1).

Further preferably, the main component A of the irradiation target comprises AlN and Be₃N₂、SrCO₃、Y₂O₃、Gd₂O₃、Sm₂O₃、TeO₂Gas sum AmO₂One kind of (1).

Further preferably, the main component A of the irradiation target is a simple substance, and the simple substance comprises²⁰⁹Bi、⁹⁸Mo、³¹P、¹⁸⁵Re、⁶²Ni、Co、⁷⁴Se, tin wire,¹²⁴Xe gas,¹⁷⁶Lu、¹⁷⁶Yb、¹⁸⁶W、²³⁵U、¹⁹¹Ir、²²⁶Ra、¹¹²Sn and distillatively purified sulfur.

The invention has the following advantages and beneficial effects:

the invention provides a method for producing radioactive isotopes by using commercial pressurized water reactor irradiation target parts. The application of the technology provides a new method for producing the radioactive isotope, and can also more fully utilize the neutron field environment in the pressurized water reactor and improve the economic performance of the pressurized water reactor.

In the invention, the irradiation target is placed in the fuel assembly guide pipe, so that irradiation resources in the reactor can be effectively utilized; moreover, in the fuel assembly, the number of the guide pipes is large (for example, a single AFA3G assembly comprises 24 guide pipes), and the arrangement position of the irradiation target is flexible. In the preferred scheme of the invention, the target is arranged in the fuel assembly in a symmetrical relationship, which is beneficial to the flattening of the power in the fuel assembly, thereby reducing the influence of the irradiation target on the power distribution of the core. In the preferred scheme of the invention, the fuel assemblies with the irradiation targets are arranged in the core in a symmetrical relationship, and the symmetrical relationship is also used for keeping the core arrangement symmetrical and reducing the influence of the irradiation targets on the power distribution of the core.

Drawings

The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention. In the drawings:

FIG. 1 is a layout of irradiation targets of the present invention in an 1/4 fuel assembly;

FIG. 2 is a diagram of the arrangement of a fuel assembly core with targets of the present invention.

Reference numbers and corresponding part names in the drawings: 1-fuel rod, 2-irradiation target, 3-empty guide tube, 4 instrument tubes.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to examples and accompanying drawings, and the exemplary embodiments and descriptions thereof are only used for explaining the present invention and are not meant to limit the present invention.