AU2018372341B2

AU2018372341B2 - Gas escape pressure testing device and method

Info

Publication number: AU2018372341B2
Application number: AU2018372341A
Authority: AU
Inventors: Xulou CAO; Shuliang CHEN; Jiangfeng LIU; Xianbiao Mao; Hongyang NI; Hai PU; Shuaibing SONG
Original assignee: Xuzhou Usure Mining Technology Co Ltd; China University of Mining and Technology CUMT; China University of Mining and Technology Beijing CUMTB
Current assignee: Xuzhou Usure Mining Technology Co Ltd; China University of Mining and Technology Beijing CUMTB
Priority date: 2017-11-23
Filing date: 2018-09-07
Publication date: 2020-10-15
Anticipated expiration: 2038-09-07
Also published as: WO2019100812A1; AU2018372341A1; RU2723232C1; CN108168768B; CN108168768A; AU2018372341A2

Abstract

A gas escape pressure testing device and a testing method, pertaining to the technical field of high-level radioactive waste disposal. The testing device comprises a cylindrical body (6) used to contain a sample (5). A sealing segment is formed on an inner wall of the cylindrical body (6). One end of the cylindrical body (6) is a gas inlet end and another end of the cylindrical body (6) is a gas discharge end. A gas delivery device is connected to the gas inlet end, and a gas monitoring device is connected to the gas discharge end. The sealing segment is fabricated on the inner wall of the cylindrical body (6), so as to enable the expansible sample (5) to expand after absorbing water in order to block the sealing segment and to achieve a seal, such that a contact surface in a vertical direction between the sample (5) and the cylindrical body (6) is no longer smooth, thereby preventing gas from escaping from the interface between the sample (5) and the cylindrical body (6), and effectively improving the accuracy of a gas escape pressure testing result.

Description

GAS ESCAPE PRESSURE TESTING DEVICE AND METHOD FIELD OF THE INVENTION

[0001] The present invention relates to the technical field of high-level radioactive waste disposal and, particularly, relates to an apparatus and method for testing the gas breakthrough pressure of a buffer material in a high-level radioactive waste disposal repository.

DESCRIPTION OF RELATED ART

[0002 In recent years, with the vigorous development of the national economy, the energy shortage has gradually become a serious problem in China, and China is paying more and more attentions to the use and development of nuclear energy. However, the use of the nuclear energy will inevitably produce a large amount of nuclear waste, so nuclear waste disposal has become a problem to be solved indeed.

[0003] For the disposal of high-level radioactive waste, a feasible solution generally accepted by the international community at the present is to bury the high-level radioactive waste in a stable formation which is 500-1000 m deep underground. That is, the high-level radioactive waste is solidified and filled, and then is stored in a deep geological disposal repository. The disposal repository is often referred to as the "high level radioactive waste geological disposal repository", hereinafter referred to as the "disposal repository".

[0004] The design idea of the disposal repository is to generally adopt a "multi-barrier system", including a surrounding rock geological barrier, an artificial barrier based on bentonite serving as a buffer material, and a waste storage container barrier. Glass solidified high-level radioactive waste is packaged in a special container, which is made of a material with extremely high corrosion resistance, such as high-grade alloy steel or copper. During disposal, a space around a solidification container is further required to be filled with a bentonite material with high adsorption performance to form multiple "artificial barriers . In addition, there is also an excellent "natural barrier". The high-level radioactive waste repository is built in a stable geological layer (such as granite, clay rock and salt rock) that is several hundred meters deep underground. As time goes on, groundwater in the surrounding rock will gradually erode into the bentonite material from the periphery, and the bentonite will gradually absorb water and expand to fill gaps between bentonite blocks and between the bentonite blocks and the surrounding rock, so as to achieve a sealing effect. As time goes on, gases may be gradually produced in the disposal repository because of complicated physical and chemical reactions, and the gases come from the following several aspects: (1) hydrogen produced by a metal tank corrosion in a bentonite and groundwater environment; (2) carbon dioxide, methane, nitrogen and the like which are produced by organic matter corrosion caused by microbial decomposition; and (3) hydrogen produced by radiation. As these gases are produced continuously, the gas pressure inside the disposal repository is increased gradually, and the gathered gases would escape to the outside. At the present, a gas breakthrough pressure value is generally tested in a triaxial pressure chamber. However, the measurement result is not accurate because of a relatively smooth contact surface between a test sample and the apparatus.

[0005] Therefore, in view of the above problem, it is necessary to provide an apparatus and method for accurately measuring the gas breakthrough pressure of a buffer material, so as to avoid the phenomenon of an inaccurate test result caused by the smooth contact surface between the test sample and a cylinder body.

SUMMARY OF THE INVENTION

Technical Problem

[0006] In view of this, the present invention provides a gas breakthrough pressure test apparatus, including a cylinder body for accommodating a test sample. A sealing section is molded on the inner wall ofthe cylinder body. By the arrangement of the sealing section, the expandable test sample absorbs water and then expands to block the sealing section for sealing, thus there is no longer a smooth contact surface between the test sample and the cylinder body in a vertical direction, and gas is avoided from breaking through from an interface of the test sample and the cylinder body, and the accuracy of the gas breakthrough pressure test result is effectively improved.

Technical Solution

[00071 The gas breakthrough pressure test apparatus provided according to the objective of the present invention includes a cylinder body, used for accommodating a test sample. One end of the cylinder body is a gas inlet end, and the other end is a gas outlet end. The gas inlet end is connected to a gas transmission apparatus, and the gas outlet end is connected to a gas monitoring apparatus. A sealing section is molded on the inner wall of the cylinder body. During testing, the test sample is in close contact with the inner wall of the cylinder body for sealing.

[00081 Preferably, the gas inlet end of the cylinder body is detachably fixedly connected to a pressure head. A gas inlet hole is formed in the pressure head, and is connected to the gas transmission apparatus. The gas outlet end of the cylinder body is detachably fixedly connected to a base. A gas outlet hole is formed in the base, and is connected to the gas monitoring apparatus. A hollow cavity is formed inside the cylinder body. The test sample is accommodated in the hollow cavity. The sealing section is molded on the inner wall, in contact with the test sample, of the cylinder body.

[0009] Preferably, the height H of the sealing section and the height Hsampie of the test sample, and the inner diameter D of the cylinder body and the diameterDsampie of the test sample have the following relations:

H - Hm 4 DI - Dampie Htap 40%l =3.75%.

[0010] Preferably, the sealing section is multiple groups of grooves uniformly distributed along an axial direction of the cylinder body. Each group of grooves is disposed along the circumference of the inner wall of the cylinder body or disposed in sections.

10011] Preferably, each of the grooves is 0.3 mm deep and 1 mm wide, and a distance between two adjacent groups of grooves is 4 mm.

[0012] Preferably, the pressure head and the base are respectively provided with a protruding part which is embedded into the hollow cavity of the cylinder body.

[0013] A gas breakthrough pressure test method which adopts the above-mentioned test apparatus is provided. The test apparatus includes a cylinder body, a pressure head and a base. A hollow cavity is formed inside the cylinder body, and a test sample is accommodated in the hollow cavity. A sealing section is molded on the inner wall, in contact with the test sample, of the cylinder body. A gas inlet hole is formed in the pressure head. A gas outlet hole is formed in the base.

[0014] The test method includes the following steps.

[0015] Step I: putting the manufactured test sample into the sealing section in the hollow cavity of the cylinder body.

[0016] Step II: increasing the humidity in a test space to allow the test sample to absorb water and expand to block the sealing section till the space is sealed.

[0017] Step III: respectively fixing the pressure head and the base at a gas inlet end and a gas outlet end of the cylinder body through bolts, connecting the gas inlet hole formed in the pressure head to a gas transmission apparatus, and connecting the gas outlet hole formed in the base to a gas monitoring apparatus.

[0018] Step IV: gradually increasing the gas pressure at the gas inlet hole from 0, and indicating that a pressure difference between the two ends is the gas breakthrough pressure of the test sample when a continuous gas flow is monitored at the gas outlet hole of the base.

[0019] Preferably, the test space is at a temperature of 200 C.

Advantageous Effect

[0020] Compared with the prior art, the apparatus for testing the gas breakthrough pressure of the buffer material in a high-level radioactive disposal repository, disclosed by the present invention, has the following advantages.

[0021] The gas breakthrough pressure test apparatus disclosed by the present invention includes the cylinder body for accommodating the test sample, and the sealing section is molded on the inner wall of the cylinder body. By processing the sealing section on the inner wall of the cylinder body, the expandable test sample absorbs water and then expands to block the sealing section for sealing, thus there is no longer a smooth contact surface between the test sample and the cylinder body in the vertical direction, and the gas is avoided from breaking through from the interface ofthe test sample and the cylinder body, and the accuracy of the gas breakthrough pressure test result is effectively improved.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to describe the embodiments of the present invention or technical solutions in the prior art more clearly, accompanying drawings required to be used in the descriptions of the embodiments or the prior art will be briefly described below. Obviously, the drawings in the descriptions below are only some embodiments of the present invention. A person of ordinary skill in the art can further obtain other drawings according to these drawings without creative work.

[00231Fig. 1 is a cross-sectional view 1 of Embodiment 1.

[0024] Fig. 2 is a cross-sectional view 2 of Embodiment 1.

[0025] Fig. 3 is a cross-sectional view 1 of Embodiment 2.

[0026] Fig. 4 is a cross-sectional view 2 of Embodiment 2.

Names of parts represented by numerals or letters in the drawings:

1: pressure head; 2: bolt; 3: protruding part; 4: groove; 5: test sample; 6: cylinder body; 7: gas outlet hole; 8: base; 9: gas inlet hole; and 10: hollow cavity.

DETAILED DESCRIPTION OF THE INVENTION

[0027] Specific implementations of the present invention are briefly described below in combination with the accompanying drawings. Obviously, the embodiments described herein are only part of the embodiments of the present invention, not all the embodiments. Based on the embodiments in the present invention, all the other embodiments obtained by a person of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

[0028] Figs. 1 to 4 show exemplary embodiments of the present invention and respectively analyze a structure in detail from different angles.

Embodiment 1

[0029] A gas breakthrough pressure test apparatus as shown in Figs. 1 and 2 includes a cylinder body 6, used for accommodating a test sample 5. One end of the cylinder body

6 is a gas inlet end, and the other end is a gas outlet end. The gas inlet end is connected to a gas transmission apparatus, and the gas outlet end is connected to a gas monitoring apparatus. A sealing section is molded on the inner wall of the cylinder body 6. There is no limitation to the structure of the sealing section as long as the test sample 5 is in close contact with the inner wall of the cylinder body 6 by absorbing water and expanding for sealing during testing and thus a non-smooth contact surface exists between the test sample 5 and the cylinder body 6. The gas transmission apparatus may be inert gas, and the gas monitoring apparatus may be a gas leakage detector or a flowmeter. If the gas leakage detector is used, gas is monitored at different time intervals, and it can be determined that the gas continuously breaks through when the gas continuously overflows. If the flowmeter is used for monitoring the gas, it can be determined that the gas continuously breaks through when detecting a sudden increase in gas flow.

[0030 Further, the gas inlet end of the cylinder body 6 is in bolted connection with a pressure head 1. A gas inlet hole 9 is formed in the pressure head 1, and is connected to the gas transmission apparatus. The gas outlet end of the cylinder body 6 is in bolted connection with a base 8. A gas outlet hole 7 is formed in the base 8, and is connected to the gas monitoring apparatus. A hollow cavity 10 is formed inside the cylinder body 6. The test sample 5 is accommodated in the hollow cavity 10. The sealing section is molded on the inner wall, in contact with the test sample 5, of the cylinder body 6. The test sample 5 absorbs water and expands to block the sealing section for sealing. Through the arrangement of the pressure head 1 and the base 8, the sealing effect of the cylinder body 6 is better. There is no limitation to connecting ways for the cylinder body 6 and the pressure head 1 as well as the base 8. Bolted connection is only an exemplary embodiment.

[0031j Further, the height H of the sealing section and the height Hsamepiofthe test sample 5, and the inner diameter D of the cylinder body 6 and the diameter Dsample of the test sample 5 have the following relations:

H- Hg D,- Dape t-= 4%; 3.75%. H, D,

[0032] An experiment shows that in such relations, the test sample 5 can block the sealing section after absorbing the water and expanding while not causing damage to an external rock mass due to an excessive expanding force.

[0033] Further, the sealing section is multiple groups of grooves 4 uniformly distributed along an axial direction of the cylinder body 6. Each group of grooves 4 is disposed along the circumference of the inner wall of the cylinder body 6 or disposed in sections.

[0034] Further, each of the grooves 4 is 0.3 mm deep and 1 mm wide, and a distance between two adjacent groups of grooves 4 is 4 mm.

Embodiment 2

[0035] The gas breakthrough pressure test apparatus as shown in Figs. 3 and 4 is the same as that of Embodiment 1, except that:

[0036] the pressure head 1 and the base 8 are respectively provided with a protruding part 3 which is embedded into the hollow cavity 10 of the cylinder body 6. The protruding part 3 cooperates with the pressure head 1 and the base 8 to facilitate the installation of a sealing ring, so that the sealing effect of the entire apparatus is better.

[0037] According to the gas breakthrough pressure test apparatus disclosed by the present invention, by processing the sealing section on the inner wall of the cylinder body 6, the expandable test sample 5 absorbs water and then expands to block the sealing section for sealing, thus there is no longer a smooth contact surface between the test sample 5 and the cylinder body 6 in the vertical direction, and the gas is avoided from breaking through from the interface of the test sample 5 and the cylinder body 6, and the accuracy of a gas breakthrough pressure test result is effectively improved.

[0038] Corresponding to the gas breakthrough pressure test apparatus of the above mentioned embodiment, the present invention further provides a gas breakthrough pressure test method. The method is implemented by using the apparatus of the above mentioned embodiment. The test method includes the following steps.

[0039] Step I: put a manufactured test sample 5 into a sealing section in a hollow cavity 10 of a cylinder body 6.

[0040] Step II: increase the humidity in a test space to allow the test sample 5 to absorb water and expand to block the sealing section till the space is sealed.

[0041] Step III: respectively fix a pressure head 1and a base 8 at a gas inlet end and a gas outlet end of the cylinder body 6 through bolts 2; a gas inlet hole 9 formed in the pressure head 1 being connected to a gas transmission apparatus; and a gas outlet hole 7 formed in the base 8 being connected to a gas monitoring apparatus.

[00421 Step IV: gradually increase the gas pressure at the gas inlet hole 9 from 0, and indicate that a pressure difference between the two ends is the gas breakthrough pressure of the test sample when a continuous gas flow is monitored at the gas outlet hole 7 of the base 8.

[0043] Further, the test space is at a temperature of 200 C.

[0044] Based on the above, the gas breakthrough pressure test apparatus disclosed by the present invention includes the cylinder body for accommodating the test sample, and the sealing section is molded on the inner wall of the cylinder body. By processing the sealing section on the inner wall of the cylinder body, the expandable test sample absorbs water and then expands to block the sealing section for sealing, thus there is no longer the smooth contact surface between the test sample and the cylinder body in the vertical direction, and the gas is avoided from breaking through from the interface of the test sample and the cylinder body, and the accuracy of the gas breakthrough pressure test result is effectively improved.

[0045] Those skilled in the art can implement and use the present invention based on the above-mentioned descriptions of the disclosed embodiments. Various modifications of these embodiments will be obvious for those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit and scope of the present invention. Therefore, the present invention is not intended to be limited to these embodiments described herein, but conforms to the widest scope consistent with the principle and novel features that are disclosed herein.

Claims

What is claimed is:

1. A gas breakthrough pressure test apparatus, comprising a cylinder body, used for accommodating a test sample, wherein one end of the cylinder body is a gas inlet end, and the other end is a gas outlet end; the gas inlet end is connected to a gas transmission apparatus, and the gas outlet end is connected to a gas monitoring apparatus; a sealing section is molded on the inner wall of the cylinder body; and during testing, the test sample is in close contact with the inner wall of the cylinder body for sealing; wherein the sealing section is multiple groups of grooves uniformly distributed along an axial direction of the cylinder body; and each group of grooves is disposed along the circumference of the inner wall of the cylinder body or disposed in sections.

2. The gas breakthrough pressure test apparatus according to claim 1, wherein the gas inlet end of the cylinder body is detachably fixedly connected to a pressure head; a gas inlet hole is formed in the pressure head, and is connected to the gas transmission apparatus; the gas outlet end of the cylinder body is detachably fixedly connected to a base; a gas outlet hole is formed in the base, and is connected to the gas monitoring apparatus; a hollow cavity is formed inside the cylinder body; the test sample is accommodated in the hollow cavity; and the sealing section is molded on the inner wall, in contact with the test sample, of the cylinder body.

3. The gas breakthrough pressure test apparatus according to claim 1 or 2, wherein the height H, of the sealing section and the heightHsampieof the test sample, and the inner diameter D, of the cylinder body and the diameter Dsampieof the test sample have the following relations:

Ht Haple D,0 Dt~SaMPIe ~7 H t "'' = 4%; D- D"'-= 3.75% .

4. The gas breakthrough pressure test apparatus according to any one of the preceding claims, wherein each of the grooves is 0.3 mm deep and 1 mm wide, and a distance between two adjacent groups of grooves is 4 mm.

5. The gas breakthrough pressure test apparatus according to any one of claims 2-4, wherein the pressure head and the base are respectively provided with a protruding part and the protruding part is embedded into the hollow cavity of the cylinder body.

6. A gas breakthrough pressure test method, adopting the test apparatus according to any one of claims 1 to 5, wherein the test apparatus comprises a cylinder body, a pressure head and a base; a hollow cavity is formed inside the cylinder body , and a test sample is accommodated in the hollow cavity; a sealing section is molded on the inner wall, in contact with the test sample, of the cylinder body; a gas inlet hole is formed in the pressure head; a gas outlet hole is formed in the base;

the test method comprises the following steps:

step I: putting the manufactured test sample into the sealing section in the hollow cavity of the cylinder body;

step II: increasing the humidity in a test space to allow the test sample to absorb water and expand to block the sealing section till the space is sealed;

step III: respectively fixing the pressure head and the base at a gas inlet end and a gas outlet end of the cylinder body through bolts, connecting the gas inlet hole formed in the pressure head to a gas transmission apparatus, and connecting the gas outlet hole formed in the base to a gas monitoring apparatus; and

step IV: gradually increasing the gas pressure at the gas inlet hole from 0, and indicating that a pressure difference between the gas inlet hole and the gas outlet hole is the gas breakthrough pressure of the test sample when a continuous gas flow is monitored at the gas outlet hole of the base.

7. The gas breakthrough pressure test method according to claim 6, wherein the test space is at a temperature of 20°C.