CN-115631877-B - System and method for producing helium-3 by heavy water of heavy water reactor moderator

CN115631877BCN 115631877 BCN115631877 BCN 115631877BCN-115631877-B

Abstract

The invention particularly relates to a method for producing helium-3 by heavy water as a moderator of a heavy water reactor, which comprises the steps of 1, carrying out negative pressure rectification on the moderator heavy water in a moderator system of the heavy water reactor unit to obtain concentrated high tritium heavy water, 2, carrying out beta decay on the concentrated high tritium heavy water in the step 1 to generate helium-3 raw material gas, and 3, carrying out active carbon adsorption, helium-argon separation and hydrogen isotope gas adsorption on the helium-3 raw material gas in the step 2 to obtain helium-3. The method for producing helium-3 by heavy water of the heavy water reactor moderator avoids the technical difficulty and high cost of helium 3/helium 4 isotope separation technically, and has high technical maturity and good economy.

Inventors

ZOU ZHENGYU
LI CHANGDA
WANG ZHONGHUI
HU YUQIAO
XIONG XIAOHONG
LI SHISHENG
YAO ZHAOHONG
LI HOUWEN
ZHENG YI
GAO XINGUO
SHEN YUN
ZHANG PENG

Assignees

中核核电运行管理有限公司
秦山第三核电有限公司

Dates

Publication Date: 20260512
Application Date: 20220930

Claims (15)

1. A method for producing helium-3 by heavy water of a heavy water reactor moderator, which is characterized by comprising the following steps: step 1, carrying out negative pressure rectification on heavy water serving as a moderator in a moderator system of a heavy water reactor unit to obtain concentrated high tritium heavy water, wherein inert gas argon is added into the concentrated high tritium heavy water to serve as a cover gas; Step 2, beta decay is carried out on the concentrated high tritium heavy water in the step 1 to generate helium-3 raw material gas, wherein the helium-3 raw material gas comprises D 2 、O 2 、N 2 、D 2 O, DTO, helium-3, argon-40, DT and T 2 ; and step 3, carrying out active carbon adsorption, helium-argon separation and hydrogen isotope gas adsorption on the helium-3 raw material gas obtained in the step 2 to obtain helium-3.
2. The method for producing helium-3 from tritium-containing heavy water in a heavy water reactor according to claim 1, wherein in the step1, the heavy water as a moderator in a moderator system of a heavy water reactor unit comprises D 2 O, DTO and impurity gases dissolved in D 2 O and DTO, the impurity gases at least comprise helium-3 and helium-4, and the heavy water as the moderator in the moderator system of the heavy water reactor unit is subjected to negative pressure rectification, the DTO enters a liquid phase, and the D 2 O and the impurity gases enter a gas phase to obtain concentrated high-weight water.
3. The method of producing helium-3 from tritium-containing heavy water in a heavy water reactor of claim 1, wherein in step 3, the hydrogen isotope gas comprises DT, T 2 , and D 2 .
4. A method for producing helium-3 from tritium-containing heavy water in a heavy water reactor according to any one of claims 1-3, characterized in that the moderator heavy water in the moderator system of the heavy water reactor unit is rectified at a pressure of 7-10kPa absolute.
5. A system for producing helium-3 by heavy water of a heavy water reactor moderator is characterized by comprising a heavy water rectifying system, a gas recovery system and a gas purifying system which are connected in sequence; the heavy water rectifying system carries out negative pressure rectification on the moderator heavy water in the moderator system of the heavy water reactor unit to obtain concentrated high tritium heavy water which is sent to the gas recovery system; Adding inert gas argon into concentrated high tritium heavy water in the gas recovery system as cover gas, and generating beta decay to generate helium-3 raw material gas which is sent to a gas purification system, wherein the helium-3 raw material gas comprises D 2 、O 2 、N 2 、D 2 O, DTO, helium-3, argon-40, DT and T 2 ; The gas purification system performs activated carbon adsorption, helium-argon separation and hydrogen isotope gas adsorption on helium-3 raw material gas to obtain helium-3.
6. The system for producing helium-3 by using heavy water reactor moderator heavy water according to claim 5, wherein the moderator heavy water in the heavy water reactor unit moderator system by using the heavy water rectification system to carry out negative pressure rectification comprises D 2 O, DTO and impurity gases dissolved in D 2 O and DTO, the impurity gases at least comprise helium-3 and helium-4, the heavy water rectification system carries out negative pressure rectification on the moderator heavy water in the heavy water reactor unit moderator system, the DTO enters a liquid phase, the D 2 O and the impurity gases enter a gas phase, and the concentrated high tritium heavy water is obtained.
7. The system for producing helium-3 from heavy water reactor moderator heavy water according to claim 6, wherein the heavy water rectification system comprises a heavy water tritium removal tower, and is used for carrying out negative pressure rectification on moderator heavy water in the heavy water reactor unit moderator system under the assistance of vacuum equipment, DTO enters a liquid phase, D 2 O and impurity gas enter a gas phase, so that concentrated low tritium heavy water and impurity gas are obtained at the top of the heavy water tritium removal tower, and concentrated high tritium heavy water is obtained at the bottom of the heavy water tritium removal tower.
8. The system for producing helium-3 by heavy water reactor moderator heavy water according to claim 7, wherein the heavy water rectifying system further comprises a heavy water upgrading tower, a product outlet at the top of the heavy water tritiation removing tower is connected with a feed inlet of the heavy water upgrading tower, the heavy water upgrading tower is used for carrying out negative pressure rectification on concentrated low tritium heavy water and impurity gas at the top of the heavy water tritiation removing tower and H 2 O leaked into the heavy water rectifying system with the aid of vacuum equipment, D 2 O enters a liquid phase, H 2 O and impurity gas enter a gas phase, so that H 2 O and impurity gas are obtained at the top of the heavy water upgrading tower, and concentrated heavy water is obtained at the bottom of the heavy water upgrading tower.
9. The system for producing helium-3 from heavy water reactor moderator according to claim 8, wherein the heavy water tritiation removal tower and the heavy water upgrading tower are formed by cascading one or more heavy water rectifying towers.
10. The system for heavy water production of helium-3 by heavy water reactor moderator according to claim 9, wherein said heavy water rectification system comprises a feed box (1), a primary heavy water rectification column (2), a secondary heavy water rectification column (3), a tertiary heavy water rectification column (4), a vacuum pump (5), a concentrated heavy water storage tank (6), a reboiler a (7), a heat exchanger a (8), a heat exchanger B (9), a reboiler B (10), a heat exchanger C (11) and a reboiler C (19); The feeding box (1) is connected with a feed inlet of a secondary heavy water rectifying tower (3), a bottom product outlet of the secondary heavy water rectifying tower (3) is connected with a feed inlet of a tertiary heavy water rectifying tower (4), a top product outlet of the tertiary heavy water rectifying tower (4) is connected with a feed inlet of the secondary heavy water rectifying tower (3), a top product outlet of the secondary heavy water rectifying tower (3) is connected with a feed inlet of a primary heavy water rectifying tower (2), the primary heavy water rectifying tower (2) is connected with a vacuum pump (5), and a bottom product outlet of the primary heavy water rectifying tower (2) is connected with a concentrated heavy water storage tank (6); The top of the primary heavy water rectifying tower (2) is provided with a heat exchanger A (8), the bottom of the primary heavy water rectifying tower (2) is provided with a reboiler A (7), the top of the secondary heavy water rectifying tower (3) is provided with a heat exchanger B (9), the bottom of the secondary heavy water rectifying tower (3) is provided with a reboiler B (10), the top of the tertiary heavy water rectifying tower (4) is provided with a heat exchanger C (11), and the bottom of the tertiary heavy water rectifying tower (4) is provided with a reboiler C (19).
11. A system for heavy water production of helium-3 with a heavy water reactor moderator according to claim 7, 8, 9 or 10, characterized in that said gas recovery system comprises a concentrated high tritium heavy water storage tank (17), a transfer pump (18) and a helium-3 raw material gas storage tank (15), said heavy water detritus bottom product outlet is connected in sequence to the transfer pump (18) and to the concentrated high tritium heavy water storage tank (17), and the gas space of said concentrated Gao Chuan heavy water storage tank (17) is connected to the helium-3 raw material gas storage tank (15).
12. The system for producing helium-3 by heavy water reactor moderator according to claim 11, wherein the gas purification system comprises an activated carbon column (13), a helium-argon separation device (12), a top circulation device (14) and a product gas storage tank (16), wherein an outlet of the helium-3 raw material gas storage tank (15) is connected with an inlet of the activated carbon column (13), an outlet of the activated carbon column (13) is connected with an inlet of the helium-argon separation device (12), an outlet of the helium-argon separation device (12) is connected with an inlet of the top circulation device (14), and an outlet of the top circulation device (14) is connected with the product gas storage tank (16).
13. The system for producing helium-3 by heavy water reactor moderator according to claim 12, characterized in that the activated carbon column (13) comprises a shell (27), a cold trap (28), an electric furnace (26), activated carbon and a filter screen (25), wherein the shell (27) and the electric furnace (26) are both placed in the cold trap (28), a cold source of the cold trap (28) is nitrogen, the activated carbon is placed in the shell (27), the electric furnace (26) is wrapped around the shell, the shell (27) is provided with an outlet and an inlet, and the outlet is provided with the filter screen (25).
14. The system for producing helium-3 by heavy water reactor moderator according to claim 12, wherein the helium-argon separation device comprises a liquefier (20), a gas-liquid separation tank (21), a freezing heat exchanger (22), a low-temperature freezer (23) and an air bath gasifier (24), wherein the outlet of the activated carbon column (13) is connected with the liquefier (20), the gas-liquid separation tank (21), the freezing heat exchanger (22), the air bath gasifier (24) and the inlet of the top circulation device (14) in sequence, and the freezing heat exchanger (22) is connected with the low-temperature freezer (23).
15. The system for heavy water reactor moderator heavy water helium-3 according to claim 12, wherein said top circulation means (14) comprises a target tube.

Description

System and method for producing helium-3 by heavy water of heavy water reactor moderator Technical Field The invention relates to the technical field of nuclear technology application, in particular to a system and a method for producing helium-3 by heavy water of a heavy water reactor moderator. Background Helium-3 has very wide application, for example, helium-3 is used as an energy fuel of a nuclear fusion reactor to generate efficient nuclear power, waste is not generated, radioactivity of the nuclear power is negligible, and the nuclear power is likely to become an important raw material for solving the long-term energy development requirement of the earth human in the future. Helium-3 is used for manufacturing a helium-3 neutron detector, and the helium-3 neutron detector has important application in the aspects of national defense, industry, environmental protection, low temperature and the like. Helium-3 is a very ideal mri sample with other isotopes of incomparable advantage when used in modern clinical medicine and chemical product structural analysis. In addition, helium-3 can be applied to the research of isotope mass spectrometry in the fields of archaeology, geology, hydrology and the like, is used for searching dark substances in universe, is used for manufacturing nuclear weapon raw materials, is used as working medium of a laser amplifier, is used as a surface probe, and is used for researching solar activity and the like. Helium-3, however, is one of two stable isotopes of hydrogen in nature, and is rarely present in nature, and the atomic abundance in natural helium is only 0.000137%, which is far from meeting the current application and research requirements. The Qinshan three-stage heavy water reactor unit is a CANDU-6 type reactor introduced from Canada, the total capacity of the assembly machine is 2 multiplied by 728Mwe, and heavy water is used as a moderator and a coolant. The heavy water is irradiated by neutrons to generate tritium in the reactor operation process, and the reaction formula is 2H＋n→3 H. Heavy water reactor units produce more tritium in the form of DTO than light water reactors. The moderator system is a main source of tritium in the heavy water reactor unit, the assembly amount of each machine is 262 tons, and more than 90 percent of moderator heavy water stays in the reactor core to be irradiated by neutrons to generate tritium during normal operation, so that the tritium generated by the moderator heavy water accounts for 97 percent of the tritium generated by the whole power plant. The tritium concentration change formula in the heavy water of the moderator system is A T＝3.42×1012×〔1-e-1.99×10-9t, wherein t is the full power operation time of the reactor. Heavy water reactor nuclear power plants produce large quantities of tritium each year. Tritium is a low-toxicity nuclide which emits beta particles with maximum energy of 18keV, has half-life of 12.3 years, short radiation range and little harm to external irradiation of human bodies. Tritium molecules such as HT, DT, T 2 in monomeric form are absorbed by lung tissue in amounts less than one thousandth and pass through the skin in small amounts and are therefore less harmful to humans. However, tritium oxides, such as HTO, DTO, T 2 O, are more detrimental than the equivalent number of tritium molecules in monomeric form. Tritium-containing water vapor is almost one hundred percent absorbed by lung tissue and skin and distributed throughout the body causing internal irradiation. Tritium has an effective half-life in vivo of 12 days. Tritium discharged from the nuclear power station enters the body through respiration and skin permeation and edible vegetables, meat and animal products and marine products, and the human body is internally irradiated to generate systemic uniformity influence. Therefore, the reduction of the emission of tritium is very important, and the radical measure for reducing the emission of tritium is to reduce the tritium specific activity of the unit coolant and the moderator. Disclosure of Invention Based on this, there is a need to provide a system and method for producing helium-3 from heavy water of a heavy water reactor moderator for high tritium heavy water of a heavy water reactor unit. In order to solve the above-mentioned purpose, the invention provides the following technical scheme: A method for producing helium-3 by heavy water of a heavy water reactor moderator comprises the following steps: step 1, carrying out negative pressure rectification on the heavy water of a moderator in a moderator system of a heavy water reactor unit to obtain concentrated high tritium heavy water; Step 2, carrying out beta decay on the concentrated high tritium heavy water in the step 1 to generate helium-3 raw material gas; and step 3, carrying out active carbon adsorption, helium-argon separation and hydrogen isotope gas adsorption on the helium-3 raw material gas obtained in the step 2 to obtai