KR101436499B1 - Fabrication method of burnable absorber nuclear fuel pellet using rapid sintering, and the burnable absorber nuclear fuel pellet thereby - Google Patents

Abstract

The present invention relates to a production method and hence the combustible absorbing nuclear fuel sintered bodies prepared in accordance with the combustible absorbing nuclear fuel sintered bodies by sintering rapid, specifically uranium dioxide (UO _2), Plutonium (IV) oxide (PuO _2), and thorium dioxide (ThO ₂₎ (Step 1); adding the boron compound to at least one fuel powder selected from the group consisting of: A step (2) of forming a molded body by molding the mixed powder mixed in the step 1; (Step 3) heating the furnace at a heating rate of 15 to 60 DEG C / min under a hydrogen atmosphere after charging the formed body manufactured in step 2 into a heating furnace; And a step (S 4) of sintering the molded body charged in the heating furnace, following the step 3, to obtain a combustible absorbing nuclear fuel sintered body. According to the method of manufacturing a combustible absorbing fuel sintered body through rapid sintering according to the present invention, sintering can be performed at a significantly low temperature as compared with conventional manufacturing processes by rapidly raising the temperature to a sintering temperature for sintering, It is possible to manufacture a sintered body having a sintered density of 90% or more while suppressing volatilization of boron even when sintering is performed at a low low temperature.

Description

[0001] The present invention relates to a flame retardant absorbent nuclear fuel pellet, and more particularly, to a flame retardant absorbent nuclear fuel pellet obtained by the rapid sintering method,

The present invention relates to a method for producing a combustible absorbing fuel sintered body through rapid sintering and a combustible absorbing nuclear fuel sintered body produced thereby.

Uranium dioxide (UO ₂₎ a sintered body (sintered pellet) is a sintered body that is most widely used as a nuclear fuel, uranium dioxide sintered body comprising 1 to 5% by weight of U ^235, while the U ²³⁵ decay by neutron generates a fission energy. As the operation cycle of the reactor core becomes longer, the operating rate of the reactor core becomes higher, which is economically advantageous. It is advantageous to install as many fissile materials as possible in the core to increase the operation cycle of the reactor core. However, if the number of fissile materials increases, the reactivity to the main foundation becomes too high, which adversely affects the safety of the reactor core. Therefore, in addition to the uranium dioxide sintered body, a combustible absorbing sintered body including a combustible absorbing material having a very high absorbency of neutrons such as gadolinium (Gd) or erbium (Er) may be used for controlling neutrons. The combustible absorption sintered body is also referred to as a combustible poison rod.

In this combustible absorbing sintered body (or combustible poison rod), a study to produce a flammable absorbing sintered body by homogeneously adding boron (B) compound such as B ₄ C as a combustible absorbing material to uranium dioxide is disclosed in Combustion Eng. LTD, it was tried at the end of the 1960s. However, there is a problem that excess oxygen of UO ₂ powder melts and reacts with boron during sintering, and B ₂ O ₃ having low boiling point is formed and volatilized, and ¹⁰ B + ¹ n → ¹¹ B (excited state) → ⁴ He + ⁷ There is a problem of an increase in the internal pressure due to helium generated in the Li reaction.

On the other hand, the Combustion Eng. The oxidation behavior of UO ₂ -B ₄ C compacts was observed in the range of 325 ℃ -1600 ℃. At this time, the oxidation reaction of B ₄ C with UO ₂ in UO ₂ was confirmed to occur throughout the test temperature, and the produced B ₂ O ₃ was reported to be almost not volatilized below 1200 ° C. It is also reported that the residual boron compound left without volatilization forms UB ₄ phase at a temperature between 1250 ° C and 1300 ° C and exists in UO ₂ . However, in order to retain the amount of boron in the sintered body to such an extent that it can serve as a combustible absorption sintered body, excessive excess boron compounds have to be added in consideration of volatilization amount. However, even in this case, there is a problem that the density of the sintered body due to excessive boron volatilization is seriously degraded, and even if sintering is carried out at a temperature of 1600 ° C, the sintered density exceeding 90% TD (theoretical density) can not be obtained.

Kraftwerk Union Aktiengesellschaft of Germany, as described in U.S. Patent No. 4774051, each of UB _x (X = 2, 4, 12) and B ₄ C powders having a size of _{2 -} And then sintered in a reducing atmosphere and a weakly oxidizing atmosphere to prepare a sintered body in which boron is homogeneously dispersed. UB _x (X = 2, 4, 12) powders were preliminarily synthesized and mixed with UO ₂ powder, and sintered at 1700 ° C similar to the conventional sinter production temperature using a reducing atmosphere such as hydrogen gas, Density sintered body, but the UB _x There is a problem in that it is difficult to apply it in the manufacturing process of the conventional nuclear fuel sintered body.

It has also been reported that when sintering is carried out at a low temperature of 1150 ° C in a weakly oxidizing atmosphere using CO ₂ gas, a sintered body in which boron having a sintered density of 95% TD (theoretical density) or more is uniformly dispersed can be produced , Which is believed to be due to the following two typical phenomena occurring when sintering UO ₂ in a weakly oxidizing atmosphere.

During the weakly oxidizing atmosphere sintering, B ₄ C may be trapped in the crystal grains at a low temperature due to grain boundary migration (abnormal grain growth) phenomenon occurring at a very high rate in AUC-UO ₂ . In addition, CO ₂ gas atmosphere is a low temperature because of the high oxygen partial pressure than a reducing gas atmosphere of oxygen / metal element (O / U) of the UO ₂ ratio is increased, that volatilization of B ₂ O ₃ do not significantly in accordance with the increase of the U diffusion coefficient (1150 ° C), the UO ₂ compact can be densified with high density. As a result, it is understood that the porosity can be effectively suppressed because the open porosity can be reduced, and the passage through which the B ₂ O ₃ is volatilized and exits the sintered body is removed.

However, this is a unique phenomenon of UO ₂ powder produced by the AUC process (wet process) and it is difficult to apply it to the DC-UO ₂ powder currently used in the domestic market. In addition, since CO ₂ gas is used as a sintering atmosphere gas in the production aspect, there is a problem of compatibility with existing fuel sintering process using hydrogen gas and reducing atmosphere sintering. CO ₂ gas having low diffusion is trapped in the pores of the sintered body There is a problem that the swelling becomes serious during the combustion of the fuel.

For this reason, not the boron is homogeneously distributed combustible absorption sintered body is the fact that in the commercial light water reactor reported bar, a situation that is being used, only a sintered body of a form coated on the surface of the boron in the current commercial light water reactor, in the domestic SiB to UO _{2 4} is uniformly added to the sintered body to produce an integral type sintered body, there has been no attempt to commercialize it.

In addition, gadolinium (Gd), which is currently most commonly used in a combustible sintered body, is in a state of unstable supply and demand due to recent surge in price, and a method for preparing it is required.

An object of the present invention is to provide a flammable absorbing sintered body by replacing gadolinium with unstable gadolinium which is unstable in supply and demand by performing sintering in a low temperature hydrogen atmosphere so as not to cause significant volatilization of boron, Absorbing fuel sintered body and a combustible absorbing nuclear fuel sintered body produced thereby.

In order to achieve the above object,

Uranium dioxide (UO _2), plutonium dioxide (PuO _2), and thorium dioxide (ThO ₂₎ adding a boron compound are mixed in the nuclear fuel powder at least one member selected from the group consisting of (Step 1);

A step (2) of forming a molded body by molding the mixed powder mixed in the step 1;

(Step 3) heating the furnace at a heating rate of 15 to 60 DEG C / min under a hydrogen atmosphere after charging the formed body manufactured in step 2 into a heating furnace; And

And a step (S 4) of sintering the molded body charged in the heating furnace, following the step 3, to produce a combustible absorbing nuclear fuel sintered body.

The present invention also provides a combustible absorbing nuclear fuel sintered body produced through the above-described method and having a boron compound homogeneously dispersed therein.

According to the method of manufacturing a combustible absorbing fuel sintered body through rapid sintering according to the present invention, sintering can be performed at a significantly low temperature as compared with conventional manufacturing processes by rapidly raising the temperature to a sintering temperature for sintering, As the sintering is performed at a low temperature, boron is prevented from being volatilized and a sintered body having a sintered density of 90% or more like that of a sintered body manufactured at a conventional high sintering temperature can be produced.

1 is a graph comparing sintering densities of combustible absorbing nuclear fuel sintered bodies according to a heating rate;
FIG. 2 is a graph showing changes in sintered density with addition of a boron compound. FIG.

The present invention

Uranium dioxide (UO _2), plutonium dioxide (PuO _2), and thorium dioxide (ThO ₂₎ adding a boron compound are mixed in the nuclear fuel powder at least one member selected from the group consisting of (Step 1);

A step (2) of forming a molded body by molding the mixed powder mixed in the step 1;

(Step 3) heating the furnace at a heating rate of 15 to 60 DEG C / min under a hydrogen atmosphere after charging the formed body manufactured in step 2 into a heating furnace; And

And a step (S 4) of sintering the molded body charged in the heating furnace, following the step 3, to produce a combustible absorbing nuclear fuel sintered body.

Hereinafter, a method of manufacturing the combustible SAR fuel assembly according to the present invention will be described in detail.

In the combustible absorbing nuclear fuel sintered body production process according to the present invention, step 1 is uranium dioxide (UO _2), Plutonium (IV) oxide (PuO _2), and thorium dioxide (ThO ₂₎ a boron compound in the nuclear fuel powder at least one member selected from the group consisting of Is added and mixed.

In the production of combustible absorbing fuel sintered bodies, gadolinium (Gd) is the most commonly used combustible neutron absorbing material at present. However, gadolinium is one of the rare earth metals whose prices have surged recently, and it is expected that gadolinium will be required in various industrial fields, and the price will be further increased, and it is predicted that the supply and demand of gadolinium will gradually become difficult. Therefore, there is a demand for a method of manufacturing a combustible absorbing fuel sintered body replacing the present gadolinium.

In the step 1 according to the present invention, a boron compound which is inexpensive and easy to purchase as compared with gadolinium is added to the nuclear fuel powder and mixed to prepare a raw material powder.

The boron compound reacts with surplus oxygen, moisture and the like in UO ₂ during sintering to form B ₂ O _3. According to the prior art, when sintering in a weakly oxidizing atmosphere to obtain a high sintering density, the boron compound is compatible with the conventional sintering process There was no problem. In addition, when sintering at a high temperature in a reducing atmosphere such as a hydrogen atmosphere, the volatilization of boron is accelerated. That is, in the reducing atmosphere sintering, the sintered density of the UO ₂ sintered body to which the boron compound is added is significantly lower than that of the UO ₂ sintered body sintered under the same conditions.

On the other hand, in the method of manufacturing a combustible absorbing fuel sintered body according to the present invention, the sintered body is manufactured by densifying UO ₂ to which a boron compound is added at a low temperature at which B ₂ O ₃ volatilization is not remarkable, , In which case the sintering of UO ₂ with boron compounds can be promoted rather than the sintering of pure UO ₂ without addition of boron compounds. This is because the liquid phase sintering that can provide a faster mass transfer path is performed as B ₂ O ₃ is present in the form of a liquid phase, and the densification of UO ₂ is performed as the liquid phase sintering is performed.

Therefore, the boron compound of the step 1 may be boron carbide (B ₄ C), titanium diboride (TiB ₂ ), zirconium diboride (ZrB), or the like, which can react with excess oxygen, moisture and the like in UO ₂ to form B ₂ O _{3 2} ), boron nitride (BN) or the like can be used. However, it is preferable to use boron nitride, but not limited thereto, and all the boron compounds capable of forming B ₂ O ₃ by reacting with excess oxygen of UO ₂ during sintering Compounds may be used.

On the other hand, deulrosseo nuclear fuel material having a uranium dioxide, which can be used as nuclear fuel powder (UO _2), Plutonium (IV) oxide (PuO _2), thorium dioxide (ThO ₂₎ has the same grating structure in the above step 1, using the appropriate combination thereof, or 1 The species fuel material may be used alone.

In addition, boron carbide (B ₄ C), titanium diboride (TiB ₂ ), zirconium diboride (ZrB ₂ ) The boron compound of step 1 in which boron nitride (BN) or the like is used is preferably added in an amount of 0.01 to 5% by weight based on the nuclear fuel powder. In the case where the boron compound is added in an amount of less than 0.01 wt% based on the nuclear fuel powder, there is a problem that it is difficult to exhibit the neutron absorbing ability by boron. When the boron compound is added in a content exceeding 5 wt% As the excess boron compound is added, there is a problem that the increase in the inner pressure of the sinter due to the swelling of the sintered body during combustion can reach a serious level.

The mixing of the step 1 can be carried out through a device such as a tubular mixer, a V-mixer, an electric mill or a ball mill. If the device is capable of producing a homogeneous mixed powder, But is not limited thereto.

In the method of manufacturing a combustible absorbing fuel assembly according to the present invention, step 2 is a step of forming a mixed powder by mixing mixed powder in step 1, and forming a molded article in which a boron compound is uniformly dispersed can do.

At this time, the molding may be performed by applying a pressure of 1 to 5 ton / cm ² . When the molding pressure is 1 ton / cm ² , There is a problem that the mixed powder is not sufficiently compressed so that the integrity is poor and the molded body is difficult to handle. If the molding pressure exceeds 5 ton / cm ² , the final sintering density is not significantly affected by excessive pressure, and wear of the molding mold may be increased.

The temperature at which the above-described molding is performed is not particularly limited, but may be performed at an appropriate temperature within a range that can be performed at room temperature and does not greatly affect the integrity of the molded body and the sintered density.

Furthermore, the molding can be performed by a conventional method such as compression molding, and the molded body produced through molding is generally cylindrical in shape suitable for the subsequent processing. At this time, in addition to the cylindrical shape, the shape of the molded body may be variously formed to suppress the pressure rise in the fuel rod, and a cylindrical shape (annular cylindrical shape) is preferably used to suppress the pressure rise in the fuel rod.

In the method for manufacturing a combustible absorbing fuel sintered body according to the present invention, step 3 is a step of heating the heating furnace at a temperature raising rate of 15 to 60 캜 / min under a hydrogen atmosphere after charging the formed body manufactured in step 2 in a heating furnace The hydrogen atmosphere may be formed using only pure hydrogen gas, and may further include a gas such as argon, nitrogen, carbon dioxide, water vapor, or the like.

In the conventional method of manufacturing the flammable absorbent fuel sintered body, the sintered body is heated at a heating rate of 3 to 10 ° C / min depending on the amount of added gadolinium (Gd), and sintered at a sintering temperature of 1700 to 1800 ° C for 4 to 8 hours It was common to perform. That is, the sintered body must be heated at a rapid heating rate in view of the productivity of producing the sintered body. However, when the sintering is performed at a high temperature of 1700 to 1800 ° C as in the conventional method, , The solubility of the added gadolinium and the grain size and the like were taken into consideration, and the sintered body was manufactured at a heating rate of 3 to 10 DEG C / min.

On the other hand, in the step 3, after the molded body is charged into the heating furnace, the furnace is rapidly heated at a temperature raising rate of 15 to 60 ° C / min, preferably 20 to 45 ° C / min, more preferably 20 to 30 ° C / Lt; / RTI > This is because the shaped body is heated at a higher heating rate than that of the conventional method, and the sintering process can be performed quickly thereby improving the productivity.

In this case, the temperature at which the temperature is raised in step 3 is 1000 to 1500 占 폚, preferably 1000 to 1400 占 폚, and more preferably 1000 to 1300 占 폚. The temperature range is lower than 1700 to 1800 ° C, which is the temperature at which sintering was performed in the conventional hydrogen atmosphere, thereby preventing the boron compound from being rapidly volatilized when sintering is performed at a high temperature. Further, by raising the temperature to a relatively low level of 1000 to 1500 ° C., there is no problem that the sintered body is broken even though the temperature increase rate is fast.

The temperature at which the temperature is raised in step 3 can be appropriately selected according to the amount of the boron compound added. If the boron compound is added in a large amount, a certain amount of B ₂ O ₃ is formed and the remaining boron compound is increased. A high sintering temperature is required. If the temperature of the step 3 is lower than 1000 ° C., the density of the sintered body produced through sintering is lowered. If the temperature of the step 3 is higher than 1500 ° C., There is a problem of volatilization.

In the method for producing a combustible absorbing fuel sintered body according to the present invention, step 4 is a step of sintering the formed body charged in the heating furnace following step 3 above.

Conventional techniques for preparing sintered combustible fuel sintered bodies by adding boron have been problematic in that the added boron is volatilized as sintering is performed at a temperature of about 1600 캜 or more. Also, the boron in order to prevent volatilization when lowering the sintering temperature, there was a problem that the density of the sintered body is lowered, the volatile low to prevent volatilization of the boron and the density decrease of boron compound UB _x Or the like, or performing sintering at a low temperature in a carbon dioxide atmosphere. However, in a conventional production process, UB _x There has been a problem that a synthetic process must be added. Furthermore, when carbon dioxide is used as the atmospheric gas, the carbon dioxide used as the atmospheric gas remains in the sintered body and swells when the fuel is burned.

On the other hand, in step 4, the sintered body of step 3 is sintered to produce a combustible absorbing fuel sintered body. The sintered body is sintered at a temperature lower than the conventional temperature to prevent volatilization of the boron, , The sintered body exhibits a high sintered density even at a low sintering temperature. That is, according to the present invention, it is possible to perform sintering in a relatively low-temperature hydrogen atmosphere only by raising the temperature at a rapid heating rate while using the existing sintered product production process as it is, And a sintered combustible fuel having high sinter density can be produced. In addition, since sintering is performed in a hydrogen atmosphere which is smaller in atomic size than carbon dioxide and easily escapes from the sintered body, it is possible to prevent the swelling of the fuel from being increased during combustion.

At this time, the sintering in step 4 may be performed at 1000 to 1500 ° C, preferably 1000 to 1400 ° C, more preferably 1000 to 1300 ° C. The sintering temperature is lower than 1700 to 1800 ° C, which is the temperature at which sintering was performed in the conventional hydrogen atmosphere, thereby preventing the boron compound from being rapidly volatilized.

Meanwhile, the sintering temperature may be the same as the temperature achieved by increasing the temperature at a high rate in the step 3, but the present invention is not limited thereto, and the sintering temperature may be adjusted in consideration of the amount of the boron compound added to the sintered body, Can be performed by selecting an appropriate temperature within the temperature range.

The sintering of step 4 may be performed by maintaining the temperature elevated in step 3 for 1 to 4 hours, but the present invention is not limited thereto. The sintering may be performed by maintaining the temperature for a suitable time according to the addition amount of the boron compound and the heating rate .

The present invention

A combustible absorbing nuclear fuel sintered body manufactured by the above manufacturing method is provided.

The sintered combustible absorbing fuel according to the present invention can prevent the boron from being volatilized as the sintering is performed at a relatively low temperature as compared with the prior art, and accordingly, the fuel material such as uranium dioxide, plutonium dioxide, thorium dioxide, B ₄ C), titanium diboride (TiB ₂ ), zirconium diboride (ZrB ₂ ), Boron compounds such as boron nitride (BN) are homogeneously dispersed. In addition, although it is produced at a relatively low sintering temperature, the temperature can be rapidly increased to the sintering temperature to exhibit a high sintering density. Furthermore, as the sintering is performed in a hydrogen atmosphere, it is excellent in compatibility with the conventional sintered body production process.

At this time, the combustible sorption fuel sintered body according to the present invention may exhibit a sintered density of 90% TD or more, preferably 95% TD or more. That is, the fuel sintered body according to the present invention can exhibit a high sintered density even when sintering is performed in a low-temperature hydrogen atmosphere.

Hereinafter, the present invention will be described in more detail by way of examples. It should be noted, however, that the following examples are illustrative of the invention and are not intended to limit the scope of the invention.

≪ Example 1 > Preparation of combustible absorbing fuel sintered body 1

Step 1: Boron carbide was added to uranium dioxide powder and mixed to prepare a mixed powder. At this time, the boron carbide was added and mixed in an amount of 0.1% by weight based on the uranium dioxide powder.

Step 2: The mixed powder prepared in step 1 was pressurized by applying a pressure of 3 ton / cm ² To prepare a molded article.

Step 3: The shaped body produced in the step 2 was charged into a heating furnace in a hydrogen atmosphere, and then rapidly heated to 1250 占 폚 at a heating rate of 20 占 폚 / min.

Step 4: The molded body rapidly heated in step 3 was sintered by holding the temperature of 1250 캜 for 1 hour, thereby preparing a combustible absorbing fuel sintered body.

≪ Example 2 > Preparation of combustible absorbing fuel sintered body 2

The sintered body of combustible absorbent nuclear fuel was prepared in the same manner as in Example 1, except that the sheet was heated to a temperature of 1250 ° C at a heating rate of 30 ° C / minute in the step 3 of Example 1.

≪ Example 3 > Preparation of combustible absorbing fuel sintered body 3

A sintered combustible fuel element sintered body was produced in the same manner as in Example 2 except that the molded body was sintered at a temperature of 1250 ° C for 2 hours in step 4 of Example 2.

Example 4 Production of combustible absorbing fuel sintered body 4

A sintered combustible fuel element sintered body was produced in the same manner as in Example 2 except that the molded body was sintered at a temperature of 1250 ° C for 4 hours in the step 4 of Example 2.

Example 5 Production of combustible absorbing nuclear fuel sintered body 5

Step 1: A mixed powder was prepared by adding boron nitride to the uranium dioxide powder and mixing them. At this time, the boron nitride was added in an amount of 0.1% by weight based on the uranium dioxide powder and mixed.

Step 2: The mixed powder prepared in step 1 was pressurized by applying a pressure of 3 ton / cm ² To prepare a molded article.

Step 3: The shaped body produced in step 2 was charged into a heating furnace in a hydrogen atmosphere, and then rapidly heated to 1250 占 폚 at a heating rate of 30 占 폚 / min.

Step 4: The molded body rapidly heated in step 3 was sintered by holding the temperature of 1250 캜 for 2 hours, thereby preparing a combustible absorbing fuel sintered body.

≪ Example 6 > Production of combustible absorbing fuel sintered body 6

The sintered combustible fuel sintered body was produced in the same manner as in Example 4, except that the molded body was sintered at a temperature of 1250 ° C for 4 hours in the step 4 of Example 4.

≪ Comparative Example 1 &

By applying a pressure of 3 ton / cm < ² > to the uranium dioxide powder and performing pressure molding The formed body was charged into a heating furnace in a hydrogen atmosphere, and then heated to 1250 占 폚 at a heating rate of 5 占 폚 / min. Thereafter, the molded body rapidly heated in the step 3 was sintered by maintaining the temperature of 1250 캜 for 1 hour, thereby preparing a flammable absorbent nuclear fuel sintered body.

≪ Comparative Example 2 &

Comparative Example 1 was repeated in the same manner as in Comparative Example 1, except that the temperature was raised to 1250 占 폚 at a heating rate of 20 占 폚 / min to prepare a combustible absorbing nuclear fuel sintered body.

≪ Comparative Example 3 &

Comparative Example 1 was repeated in the same manner as in Comparative Example 1, except that the temperature was raised to 1250 占 폚 at a heating rate of 30 占 폚 / min to prepare a combustible absorbing nuclear fuel sintered body.

≪ Comparative Example 4 &

The sintered combustible fuel sintered body was manufactured in the same manner as in Example 1, except that the sintered body was heated to a temperature of 1250 ° C at a heating rate of 5 ° C / minute in the step 3 of Example 1.

EXPERIMENTAL EXAMPLE 1 Analysis of Sintered Density of Flammable Absorption Fuel Sintered Body

The sintered densities of the combustible absorbing fuel sintered bodies produced in Examples 1 to 6 and Comparative Examples 1 to 4 according to the present invention were analyzed using an immersion method. The results are shown in Figs. 1 and 2 .

As shown in FIG. 1, it can be seen that the sintered bodies of the fuel produced in Comparative Examples 1 to 4 and Examples 1 and 2 have higher sintering densities as the heating rate is higher. At this time, when the boron compound was not added in Comparative Examples 1 to 3, it remained at the maximum 85% TD level. However, it can be seen that the sintered fuel bodies produced in Examples 1 and 2 have a sintered density exceeding 90% TD, which is a value higher than 5% as compared with Comparative Example 4 in which the rate of temperature rise is as low as 5 ° C / min Able to know.

Further, as shown in FIG. 2, it can be seen that the sintering density also increases with increasing sintering time. However, when the sintering is carried out for 4 hours or more, it is expected that the effect of improving the sintering density according to the sintering time will be insignificant. Therefore, it is preferable to perform sintering for 1 to 4 hours. Furthermore, it was found that the sintered densities of Examples 5 and 6 in which boron nitride was added as a boron compound exhibited a high sintered density of 95% TD or higher.

From the above analysis results, it was confirmed that the sintered density can be further improved by adding a boron compound to the sintered combustible absorbing fuel according to the present invention and rapidly raising the temperature to the sintering temperature.

Claims (15)

Uranium dioxide (UO _2), Plutonium (IV) oxide (PuO _2), and thorium dioxide (ThO ₂₎ in nuclear fuel powder at least one member selected from the group, nitride (BN), or boron carbide, boron as a boron compound consisting of (B ₄ C) (Step 1);
A step (2) of forming a molded body by molding the mixed powder mixed in the step 1;
Charging the formed body produced in step 2 into a heating furnace, and then raising the temperature of the furnace to 1000 to 1500 占 폚 at a heating rate of 15 to 60 占 폚 / min in a hydrogen atmosphere (step 3); And
(Step 4) of sintering the formed body charged in the heating furnace at a temperature of 1000 to 1500 캜 under a hydrogen atmosphere, following step 3 above.
delete The method according to claim 1, wherein the boron compound of step 1 is boron nitride (BN).
The method of claim 1, wherein the boron compound of step 1 is added and mixed in an amount of 0.01 to 5 wt% based on the nuclear fuel powder.
The method according to claim 1, wherein the molded body of step 2 is produced by applying a pressure of 1 to 5 ton / cm ² .
The method according to claim 1, wherein the hydrogen atmosphere in step (3) is a hydrogen atmosphere further comprising at least one gas selected from the group consisting of argon, nitrogen, carbon dioxide, and water vapor.
delete The method according to claim 1, wherein the temperature raised in step (3) is 1000 to 1400 占 폚.
The method of claim 1, wherein the temperature raised in step (3) is 1000 to 1300 ° C.
delete The method of claim 1, wherein the sintering of step (4) is performed at a temperature of 1000 to 1400 캜.
The method according to claim 1, wherein the sintering step (4) is performed at a temperature of 1000 to 1300 캜.
A combustible sorption fuel fuel sintered body produced by the method according to claim 1, wherein the boron compound is homogeneously dispersed and has a theoretical density of 90% or more.
delete 14. The combustible absorbing nuclear fuel assembly according to claim 13, wherein the density of the combustible absorbing fuel sintered body is 95% or more theoretical density (TD).

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