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Improved performance oxide ceramic core for thermal neutron reactor and preparation method

An oxide ceramic and reactor technology, which is applied in the fields of reactor fuel material, nuclear power generation, and greenhouse gas reduction, etc., can solve the problems of control affecting reactivity, affecting the safety and controllability of the reactor, and reducing the reactivity value of neutron absorbers, etc. Achieve the effect of improving thermal conductivity, improving moderation performance, and improving reactivity value

Active Publication Date: 2015-10-28
SHANGHAI NUCLEAR ENG RES & DESIGN INST CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Since most reactors are designed with UO 2 fuel, and the MOX fuel loaded later needs to maintain structural compatibility, so it is difficult to alleviate the above adverse phenomena through structural design changes
In addition, the reactivity value of the neutron absorber is closely related to the neutron energy spectrum. In some reactors loaded with MOX fuel, due to the hard neutron energy spectrum, the reactivity value of the neutron absorber decreases, which affects the reactivity. control, thereby affecting the safety and controllability of the reactor

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  • Improved performance oxide ceramic core for thermal neutron reactor and preparation method
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Embodiment 1

[0027] The present invention will be further described by taking the uranium-plutonium mixed oxide fuel core (MOX) fuel core for PWR as an example.

[0028] MOX contains Pu extracted from spent fuel, and using MOX fuel core as PWR fuel can improve the utilization rate of nuclear fuel; but PuO 2 The presence of the MOX core makes the thermal conductivity lower than that of ordinary UO 2 Core body, the higher temperature of the core body affects the operation performance of the core; at the same time, the introduction of Pu element will harden the neutron spectrum of the core, thereby reducing the reactivity value of the neutron absorber.

[0029] The present invention adds a second phase material with high thermal conductivity and moderation to MOX. The second phase material is BeO, an ultra-high thermal conductivity oxide material, and the addition ratio is shown in Table 1 below. BeO forms a continuous phase in MOX, as shown in figure 1 As shown, an oxide ceramic core with ...

Embodiment 2

[0042] An oxide ceramic core body with improved performance for thermal neutron reactors according to the present invention and its preparation method are as follows:

[0043] (1) Raw material preparation: oxide ceramic core powder and second phase material powder are shown in Table 3;

[0044] table 3

[0045] Element

Ratio (mass percentage)

UO 2

90.4%

PuO 2

6.6%

BeO

3.0%

[0046] (2) Mixing: mix and ball mill the oxide ceramic core powder and the second phase material powder described in step (1), and the milling time is 45 minutes; before mixing and milling, the oxide ceramics described in step (1) The core powder is pre-fired, and the pre-fire time is 3 hours;

[0047] (3) Compact: Cool the powder mixed in step (2) to form a green compact with a pressure of 200MPa;

[0048] (4) Sintering: put the green body obtained in step (3) into a sintering furnace for sintering, the sintering temperature is 1750°C, sintering...

Embodiment 3

[0051] An oxide ceramic core body with improved performance for thermal neutron reactors according to the present invention and its preparation method are as follows:

[0052] (1) Raw material preparation: oxide ceramic core powder and second phase material powder are shown in Table 4;

[0053] Table 4

[0054] Element

[0055] PuO 2 10.6%

[0056] (2) Mixing: mix and ball mill the oxide ceramic core powder and the second phase material powder described in step (1), and the ball milling time is 2 hours; The core powder is pre-fired for 5 hours;

[0057] (3) Compact: Cool the powder mixed in step (2) to form a green compact with a pressure of 200MPa;

[0058] (4) Sintering: put the green body obtained in step (3) into a sintering furnace for sintering, the sintering temperature is 1700°C, sintering for 1h, the sintering atmosphere is argon and hydrogen mixed gas, and the gas mole percentage is: hydrogen is 7%, Argon is 93%, and the added second phase m...

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Abstract

The present invention provides a performance-modified oxide ceramic core body for a thermal neutron reactor, and a preparation method thereof. According to the present invention, a second phase material is added to an oxide ceramic core body, and the added second phase material forms a continuous phase in the oxide ceramic core body to obtain a performance-modified oxide ceramic core body, wherein the mass of the second phase material is 0.3-15% of the total mass of the performance-modified oxide ceramic core body; the preparation steps comprise: raw material preparation, mixing, green compacting and sintering; compared with the common core body with no specified component addition, the performance-modified oxide ceramic core body for the thermal neutron reactor has a low temperature; and the fuel assembly adopting the core body has the following characteristics that: a neutron energy spectrum is softened, a ratio of a fast neutron flux to a thermal neutron flux in the assembly is reduced by about 35%, and a reactivity value of a neutron absorption body is increased by about 25%.

Description

technical field [0001] The invention relates to the field of nuclear fuel, in particular to an oxide ceramic core with improved performance for thermal neutron reactors and a preparation method thereof. Background technique [0002] Nuclear fuel cores come in the form of metal fuel, dispersed fuel, ceramic fuel, etc. Among them, due to the relatively low phase transition temperature and melting point of the metal fuel, it is difficult to use it at a relatively high operating temperature in the power reactor, and the size change caused by irradiation growth is relatively large; in order to achieve a certain fissile nuclide nuclei density, it is necessary to increase the enrichment of fuel; and ceramic fuel has been widely used in power reactors because of its relatively stable size, high melting point, and low enrichment. [0003] A serious disadvantage of the ceramic fuel core is poor thermal conductivity, which makes the temperature gradient between the central part and th...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B35/01C04B35/622G21C3/62
CPCY02E30/34Y02E30/38Y02E30/30
Inventor 丁阳李继威毕光文周勤汤春桃朱丽兵陈磊李志勇
Owner SHANGHAI NUCLEAR ENG RES & DESIGN INST CO LTD
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