阅读说明：本技术 颗粒可燃毒物反应性控制方法、可燃毒物板及燃料棒 (Method for controlling reactivity of particle burnable poison, burnable poison plate and fuel rod ) 是由 娄磊 柴晓明 姚栋 王连杰 于颖锐 李庆 彭星杰 夏榜样 陈长 刘同先 李满仓 于 2020-11-19 设计创作，主要内容包括：本发明提供的颗粒可燃毒物反应性控制方法、可燃毒物板及燃料棒,该方法通过设定堆芯寿期初剩余反应性大小和寿期长短,并将堆芯寿期初剩余反应性大小和寿期长短输入到堆芯反应性与燃耗变化模型中,得到颗粒可燃毒物参数；颗粒可燃毒物参数包括颗粒类型、颗粒直径、颗粒体积份额、颗粒掺杂率和颗粒孔隙率；基于颗粒可燃毒物参数选择目标颗粒可燃毒物,加入堆芯中,提高毒物燃耗速率,减少寿期末可燃毒物残留,而且便于可燃毒物分段,有利于堆芯剩余反应性的控制。(According to the reactivity control method for the particle burnable poison, the burnable poison plate and the fuel rod, provided by the invention, the particle burnable poison parameter is obtained by setting the initial residual reactivity and the long service life of the reactor core, and inputting the initial residual reactivity and the long service life of the reactor core into a reactor core reactivity and burnup change model; the particle burnable poison parameters include particle type, particle diameter, particle volume fraction, particle doping rate, and particle porosity; target particle burnable poison is selected based on the particle burnable poison parameters and added into the reactor core, so that the burnup rate of the burnable poison is improved, the burnable poison residue at the end of the service life is reduced, the burnable poison is convenient to segment, and the control of the residual reactivity of the reactor core is facilitated.)

1. A method for controlling reactivity of a particulate burnable poison, comprising:

setting the initial residual reactivity and the long and short service life of the reactor core, and inputting the initial residual reactivity and the long and short service life of the reactor core into a reactor core reactivity and burnup change model to obtain particle burnable poison parameters; the particle burnable poison parameters comprise particle type, particle diameter, particle volume fraction, particle doping rate and particle porosity;

selecting a target particulate burnable poison for addition to the core based on the particulate burnable poison parameter.

2. The method of claim 1, wherein the particle types include boron-containing compounds, gadolinium-containing compounds, erbium-containing compounds, hafnium-containing compounds, europium-containing compounds, dysprosium-containing compounds, silver, indium, and cadmium.

3. The method of claim 1, wherein the particle diameter is in the range of 50 to 500 μm.

4. The method of claim 1, wherein the volume fraction of the particles is in the range of 0 to 50%.

5. The method of claim 1, wherein the particle doping level is 0-20%.

6. The method of claim 4, wherein the particle porosity is 0-40%.

7. A burnable poison fuel rod, comprising:

and uniformly and randomly dispersing the target particle burnable poison in the fuel matrix to form the burnable poison fuel rod.

8. The burnable poison fuel rod of claim 7, wherein the enrichment of the fuel matrix is 4.45% and the particle type of the target particulate burnable poison is B₄C. The particle diameter is 100 μm, the volume fraction of the particles is 5%, the doping rate of the particles is 0%, and the porosity of the particles is 0%.

9. A burnable poison plate, comprising:

and forming the burnable poison pellets by combining the target particle burnable poisons into a separated burnable poison, and forming a burnable poison plate based on the burnable poison pellets.

10. The burnable poison plate of claim 9, wherein the burnable poison pellets have a diameter of 500 μm, and the particle type of the target particulate burnable poison is Er₂O₃The volume fraction of the particles is 45 percent, the doping rate of the particles is 20 percent, the base material of the burnable poison plate is doped with zirconium, and the porosity of the particles is 0 percent.

Technical Field

The invention relates to the technical field of nuclear reactor cores, in particular to a reactivity control method of particle burnable poison, a burnable poison plate and a fuel rod.

Background

In the design of a reactor core, the residual reactivity of the core is generally controlled by soluble boron, burnable poison, control rods and the like because the initial and middle life of the core often have large residual reactivity. The burnable poison is used as a neutron absorption material, and a spatial self-shielding effect can occur when the burnable poison exists in a reactor core in a particle form, so that the material on the outer surface of the particle can absorb neutrons firstly, and the material from the inside of the particle to the central area can absorb the neutrons less or even can not absorb the neutrons. Due to the space self-shielding effect, the granular burnable poison is compared with the same amount of uniformly distributed burnable poison, only part of the burnable poison plays a role in inhibiting reactivity at the beginning of the core life, so that the initial reactivity of the core life is not too low, the granular burnable poison is burnt in an onion peeling mode along with the burning, the neutron action of the burnable poison can be slowly released, the residual reactivity of the fuel can be inhibited for a proper and long time period, and the control of the reactor core reactivity is facilitated. However, the influence of the particle type and volume fraction of the burnable poison in particle form added to the fuel matrix on the residual reactivity of the core is only considered from a macroscopic point of view, and the influence of the burnable poison in particle form on the residual reactivity of the core is not considered from a microscopic point of view (such as particle size, particle volume fraction, particle doping rate, particle porosity).

Disclosure of Invention

The invention aims to solve the technical problem of how to consider the influence of the particle-form burnable poison on the residual reactivity of a reactor core from the parameters of the particle-form burnable poison, and therefore, the invention provides a particle burnable poison reactivity control method, a burnable poison plate and a fuel rod.

The invention is realized by the following technical scheme:

a method of controlling reactivity of particulate burnable poison, comprising:

setting the initial residual reactivity and the long and short service life of the reactor core, and inputting the initial residual reactivity and the long and short service life of the reactor core into a reactor core reactivity and burnup change model to obtain particle burnable poison parameters; the particle burnable poison parameters comprise particle type, particle diameter, particle volume fraction, particle doping rate and particle porosity;

selecting a target particulate burnable poison for addition to the core based on the particulate burnable poison parameter.

Further, the particle types include boron-containing compounds, gadolinium-containing compounds, erbium-containing compounds, hafnium-containing compounds, europium-containing compounds, dysprosium-containing compounds, silver, indium, and cadmium.

Further, the particle diameter is in the range of 50-500 μm.

Further, the volume fraction of the particles is in the range of 0-50%.

Further, the particle doping rate is 0-20%.

Further, the porosity of the particles is 0-40%.

A burnable poison fuel rod comprising:

and uniformly and randomly dispersing the target particle burnable poison in the fuel matrix to form the burnable poison fuel rod.

Further, the enrichment of the fuel matrix is 4.45%, and the particle type of the target particulate burnable poison is B₄C. The particle diameter is 100 μm, the volume fraction of the particles is 5%, the doping rate of the particles is 0%, and the porosity of the particles is 0%.

A burnable poison plate comprising:

and forming the burnable poison pellets by combining the target particle burnable poisons into a separated burnable poison, and forming a burnable poison plate based on the burnable poison pellets.

Further, the diameter of the burnable poison pellet is 500 mu m, and the particle type of the target particle burnable poison is Er₂O₃The volume fraction of the particles is 45 percent, the doping rate of the particles is 20 percent, the base material of the burnable poison plate is doped with zirconium, and the porosity of the particles is 0 percent.

Compared with the prior art, the invention has the following advantages and beneficial effects:

1. by selecting the particle burnable poison, the space self-shielding effect of the burnable poison is increased, the neutron absorption capacity of the burnable poison at the beginning of the service life is reduced, the consumption rate of the burnable poison in the service life is reduced, and the effective control and the slow release of the residual reactivity of the reactor core are facilitated.

2. The particle type, the particle size, the particle volume fraction, the particle doping rate and the particle porosity of the particle burnable poison are determined according to the initial residual reactivity of the reactor core and the long service life of the reactor core, the spatial self-shielding effect of the particle burnable poison is controlled and controlled according to neutron absorption cross sections of different particle types and different particle sizes, the influence of the particle burnable poison on the system reactivity is determined according to different particle volume fractions, the influence on the equivalent absorption cross section of the particle burnable poison is determined according to different particle doping rates and different particle porosities, the residual reactivity of the reactor core is controlled, the residual reactivity of the reactor core in the whole service life range is effectively controlled, the power distribution of the reactor core is flattened, the requirements of the shutdown allowance and the 'stick sticking' criterion under the cold normal pressure working condition are met, and the design flexibility and the operation safety of the reactor core.

3. The target particle burnable poison is dispersed in the fuel matrix, so that the burnable poison does not occupy the position of a fuel grid cell, and does not generate serious power distortion to influence the flattening of power distribution.

4. The target particle burnable poison is combined into a separated burnable poison to form a burnable poison pellet, so that the absorption area of the burnable poison is increased, the burnup rate of the burnable poison is increased, the burnable poison residue at the end of the service life is reduced, the burnable poison is segmented conveniently, and the control of the residual reactivity of the reactor core is facilitated.

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 top view of a burnable poison fuel rod of the present invention.

FIG. 2 is a side view of a burnable poison fuel rod of the present invention.

Fig. 3 is a schematic structural view of a burnable poison plate according to the present invention.

Reference numerals: 1. a moderator; 2. cladding; 3. a fuel matrix; 4. particulate burnable poison.

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.

Example 1

The invention provides a reactivity control method for a particle burnable poison, which comprises the following steps:

setting the initial residual reactivity and the long service life of the reactor core, and inputting the initial residual reactivity and the long service life of the reactor core into a reactor core reactivity and burnup change model to obtain particle burnable poison parameters; the particle burnable poison parameters include particle type, particle diameter, particle volume fraction, particle doping rate, and particle porosity; a target particulate burnable poison is selected for addition to the core based on the particulate burnable poison parameter.

Wherein particulate burnable poison means burnable poison present in particulate form. Compared with the burnable poison in a conventional uniformly distributed form, the burnable poison in a particle form can increase the spatial self-shielding effect of the burnable poison and reduce the neutron absorption capacity of the burnable poison at the beginning of the service life, thereby reducing the consumption rate of the burnable poison in the service life and being beneficial to the effective control and slow release of the system reactivity.

Specifically, the parameters of the burnable poison particles are adjusted according to the initial residual reactivity of the reactor core and the long and short service life of the reactor core, so as to realize the control of the residual reactivity of the reactor core. Wherein the particle types of the particulate burnable poison include, but are not limited to, boron-containing compounds, gadolinium-containing compounds, erbium-containing compounds, hafnium-containing compounds, europium-containing compounds, dysprosium-containing compounds, silver, indium, and cadmium. The boron-containing compound in this example is present in the form B₄C. The gadolinium-containing compound is in the form of Gd₂O₃The erbium-containing compound exists in the form of Er₂O₃The hafnium-containing compound is present as Hf, and the europium-containing compound is present as Eu₂O₃Dy exists in the form of the dysprosium-containing compound₂O₃Silver In the form of Ag, indium In the form of In, cadmium In the form of Cd, etc., it being understood that particulate burnable poisons of different particle types have different neutron absorption cross sections.

The particle size controls the space self-shielding effect of the particle burnable poison, and the particle diameter range of the particle burnable poison is set to be 50-500 mu m in the embodiment; the particle volume fraction controls the influence of the whole particle burnable poison on the residual reactivity of the reactor core, and the particle volume fraction range of the particle burnable poison is 0-50% in the embodiment; the particle doping rate and the particle porosity of the particle burnable poison also influence the equivalent absorption cross section of the poison particles, and the absorption cross section of the particle burnable poison influences the control capability of the particle burnable poison on the residual reactivity of the reactor core, in the embodiment, the particle doping rate of the particle burnable poison is 0-20%, and the particle porosity of the particle burnable poison is 0-40%.

By the reactivity control method for the particle burnable poison, the residual reactivity of the reactor core can be effectively controlled within the whole life span of the reactor core, the power distribution of the reactor core is flattened, the requirements of shutdown allowance and 'rod clamping' criterion under the cold-state normal-pressure working condition are met, and the design flexibility and the operation safety of the reactor core are improved.

Example 2

As shown in FIGS. 1 and 2, the selected particulate burnable poison is uniformly and randomly dispersed in the fuel matrix, and the matrix fuel enrichment is 4.45% for the first core life and the length of the life, with the type of particles B being the type₄C. The reactivity is controlled by the particle diameter of 100 mu m, the volume fraction of the particles is 5 percent, and the particle doping rate and the particle porosity are 0 percent, the neutron absorption effect of the toxic is gradually released by the spatial self-shielding effect of the particle combustible toxic, the burnup rate of the toxic is effectively controlled, and the reactivity of the reactor core in the whole life period is effectively controlled.

Specifically, the target particle burnable poison is dispersed in the fuel matrix, so that the burnable poison does not occupy the position of a fuel cell, and meanwhile, the burnable poison does not generate serious power distortion to influence the flattening of power distribution.

Example 3

As shown in fig. 3, the target particulate burnable poison may not only be dispersed in the fuel matrix, but also be used to form separate burnable poisons, form burnable poison pellets, and then form a burnable poison plate using the burnable poison pellets. In the embodiment, Er2O3 pellets are adopted in the separated burnable poison plate, the diameter of the burnable poison pellets is 500 mu m, the volume fraction of particles is 45%, and the particle doping rate is 20%. The burnable poison plate substrate material of this example was doped with zirconium, and the particle porosity was 0%.

Specifically, the separated burnable poison composed of the target particle burnable poison is beneficial to increasing the absorption area of the burnable poison, can also increase the burnup rate of the burnable poison so as to reduce the poison residue at the end of the service life, is convenient for poison segmentation and is beneficial to controlling the residual reactivity of the reactor core. The burnable poison plate form formed by the burnable poison pellets is burnt faster than a solid plate in a reactor core, the absorption capacity of the burnable poison plate form to neutrons can be adjusted through parameters of granular burnable poisons, and the residual quantity of the burnable poisons at the end of the service life is small.

The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.