AU2021102791A4 - Apparatus for Studying the Adsorption Mechanism of Nuclides in Single Fissure Natural Granite - Google Patents
Apparatus for Studying the Adsorption Mechanism of Nuclides in Single Fissure Natural Granite Download PDFInfo
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- 239000010438 granite Substances 0.000 title claims abstract description 93
- 238000001179 sorption measurement Methods 0.000 title claims abstract description 77
- 230000007246 mechanism Effects 0.000 title claims abstract description 20
- 239000011435 rock Substances 0.000 claims abstract description 86
- 238000013508 migration Methods 0.000 claims abstract description 58
- 230000005012 migration Effects 0.000 claims abstract description 58
- 239000003673 groundwater Substances 0.000 claims abstract description 48
- 239000007788 liquid Substances 0.000 claims abstract description 46
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 23
- 238000000034 method Methods 0.000 claims abstract description 19
- 230000008569 process Effects 0.000 claims abstract description 16
- 238000002474 experimental method Methods 0.000 claims abstract description 15
- 230000001105 regulatory effect Effects 0.000 claims abstract description 9
- 238000004088 simulation Methods 0.000 claims abstract description 5
- 239000000243 solution Substances 0.000 claims description 35
- 239000000700 radioactive tracer Substances 0.000 claims description 30
- 239000003463 adsorbent Substances 0.000 claims description 26
- 239000003795 chemical substances by application Substances 0.000 claims description 26
- 238000012360 testing method Methods 0.000 claims description 25
- 230000002572 peristaltic effect Effects 0.000 claims description 18
- CPELXLSAUQHCOX-UHFFFAOYSA-M Bromide Chemical compound [Br-] CPELXLSAUQHCOX-UHFFFAOYSA-M 0.000 claims description 17
- 150000002500 ions Chemical class 0.000 claims description 12
- 239000004816 latex Substances 0.000 claims description 11
- 229920000126 latex Polymers 0.000 claims description 11
- 238000007789 sealing Methods 0.000 claims description 11
- 238000013461 design Methods 0.000 claims description 10
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- 238000000576 coating method Methods 0.000 claims description 9
- 239000003822 epoxy resin Substances 0.000 claims description 7
- 229920000647 polyepoxide Polymers 0.000 claims description 7
- 238000011160 research Methods 0.000 claims description 7
- 229910052770 Uranium Inorganic materials 0.000 claims description 6
- 238000005273 aeration Methods 0.000 claims description 6
- 229910052500 inorganic mineral Inorganic materials 0.000 claims description 6
- 238000005259 measurement Methods 0.000 claims description 6
- 239000011707 mineral Substances 0.000 claims description 6
- JFALSRSLKYAFGM-UHFFFAOYSA-N uranium(0) Chemical compound [U] JFALSRSLKYAFGM-UHFFFAOYSA-N 0.000 claims description 6
- 230000000694 effects Effects 0.000 claims description 5
- 230000001276 controlling effect Effects 0.000 claims description 4
- 239000011521 glass Substances 0.000 claims description 4
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- 238000005070 sampling Methods 0.000 claims description 4
- 238000010998 test method Methods 0.000 claims description 4
- 150000001450 anions Chemical class 0.000 claims description 3
- 230000009286 beneficial effect Effects 0.000 claims description 3
- 238000013480 data collection Methods 0.000 claims description 3
- 238000002354 inductively-coupled plasma atomic emission spectroscopy Methods 0.000 claims description 3
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- 238000000691 measurement method Methods 0.000 claims description 3
- 230000035515 penetration Effects 0.000 claims description 3
- 239000000843 powder Substances 0.000 claims description 3
- 238000002203 pretreatment Methods 0.000 claims description 3
- 238000012546 transfer Methods 0.000 claims description 3
- 238000009423 ventilation Methods 0.000 claims description 3
- 239000012153 distilled water Substances 0.000 claims description 2
- 238000010586 diagram Methods 0.000 abstract description 5
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Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume, or surface-area of porous materials
- G01N15/08—Investigating permeability, pore-volume, or surface area of porous materials
- G01N15/082—Investigating permeability by forcing a fluid through a sample
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/24—Earth materials
-
- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21F—PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
- G21F9/00—Treating radioactively contaminated material; Decontamination arrangements therefor
- G21F9/04—Treating liquids
- G21F9/20—Disposal of liquid waste
- G21F9/24—Disposal of liquid waste by storage in the ground; by storage under water, e.g. in ocean
Abstract
An apparatus for studying the adsorption mechanism of nuclides in single fissure natural
granite is disclosed in the invention. Specifically, the simulation apparatus comprises a liquid
supply regulating device with variable speed, an adsorption and migration rock pillar device,
an automatic effluent collection device, a pressure and temperature sensor, a barometer and a
gas cylinder. Putting undisturbed granite core with single fissure into the adsorption and
migration rock pillar device and using gas cylinders to vent and seal it. Then, the liquid supply
regulating device with variable speed is connected to the adsorption and migration rock pillar
device to provide synthetic groundwater for the apparatus. The effluent of the whole process is
automatically collected by the automatic effluent collection device. The method can not only
study the patterns of nuclide adsorption and migration under the combined action of water and
rock in granite fissures, but also carry out conditional experiments and parallel experiments of
different influencing factors, which plays a vital role in accurately simulating and predicting
the adsorption and migration distribution of nuclides.
1/2
FIGURES
bV
9 291
6-- 5- [:
421
-22
28- --
15 1 2 2
2 27
•1 A I: B i I~ - - - - - I
Figure 1 A schematic structural diagram of the apparatus for studying the adsorption
mechanism of nuclides in single fissured natural granite.
Description
1/2
9 291
6-- 5- [: bV 421 -22 28- --
15 1 2 2
2 27
•1 I~ A -- - - - I I: B i Figure 1 A schematic structural diagram of the apparatus for studying the adsorption
mechanism of nuclides in single fissured natural granite.
Apparatus for Studying the Adsorption Mechanism of Nuclides in Single Fissure
Natural Granite
The invention relates to the technical field of radionuclide adsorption and migration, in
particular to an apparatus for studying the adsorption mechanism of nuclides in single
fissure natural granite.
The invention relates to the technical field of radionuclide adsorption and migration, in
particular to an apparatus for studying the adsorption mechanism of nuclides in single
fissure natural granite. In order to cope with the increasing risk of nuclear waste leakage,
nuclear nations in the world have chosen to set up deep geological repositories or
underground laboratories to bury nuclear waste in underground rock stratum, so as to
effectively isolate it from the biosphere. However, during the long-term storage of
nuclear waste, the storage tanks may leak due to corrosion or changes in geological
environment, and radionuclides (Pu, U, Se, Sr, Am, Cs, Eu and Tc, etc.) will be released
into the surrounding rocks, which are mainly granite in China. In practice, the
permeability of granite itself is low, but the fissures and fracture zones in granite have
strong permeability. Therefore, the migration of nuclides in granite mainly occurs in
granite fissures or fracture zones, in which nuclides migrate outward along with
groundwater flow, and finally enter the biosphere, threatening ecological security and
human health. Therefore, it is very important to study the adsorption and migration of
nuclides in granite fissures under the interaction of water and rock.
At present, the simulation method of radionuclide adsorption and migration in laboratory
is mainly aimed at powdered rock minerals, and vertical or horizontal packed pillar are
established. Using powdered natural rock for the study of adsorption and migration laws
can provide quantitative data related to adsorption and migration behaviour or
mechanism, but crush is considered to be the main reason for the increase in rock
adsorption capacity because it creates additional surface and reaction sites. At different
crush degrees, the adsorption capacity will also be different. Therefore, the traditional
study of powdered minerals is too idealistic, and there may be a big error when the
experimental data is used to predict and simulate the actual adsorption and migration of
nuclides in granite, which is not in line with the actual situation. Therefore, it is necessary
to invent an apparatus to study the solute transport law of radionuclides in granite
fissures, which has great research value in accurately simulating and predicting the
distribution characteristics of radionuclide adsorption and migration.
An apparatus for studying the adsorption mechanism of nuclides in single fissure natural
granite is provided in the invention, which comprises a liquid supply regulating device
with variable speed, an adsorption and migration rock pillar device, an automatic effluent
collection device, a pressure and temperature sensor, a barometer and a gas cylinder.
Specifically, the liquid supply regulating device with variable speed consists of a liquid
supply bottle, a synthetic groundwater solution, a liquid supply pipe and a peristaltic
pump. The liquid supply bottle is filled with synthetic groundwater solution, which is
prepared with reference to the actual groundwater ion composition in the field sampling
area. The peristaltic pump provides the driving force for the whole system, and the flow rate can be adjusted as required. The synthetic groundwater solution is delivered to the adsorption and migration rock pillar device through the liquid supply pipe.
The adsorption and migration rock pillar device is the core area of the whole device,
including pressure chamber top cover, pressure chamber bottom cover, sample top cover,
sample lower seat, water permeable plate, quick connector, granite pillar (containing
single fissure), transparent latex film, organic glass cover, O-ring, bracket, vertical pillar,
several hexagonal nuts, gas inlet and outlet pipes, adjustable telescopic rod and adjusting
rod. The synthetic groundwater solution enters the granite pillar after passing through the
quick connector, the sample lower seat and the water permeable plate, and then flows into
the automatic effluent collection device after passing through the adjusting rod and the
quick connector.
The automatic effluent collection device includes effluent pipe, effluent, sample
collection test tube and automatic fraction collector . The function of the device is to
automatically collect the liquid flowing out of the adsorption and migration rock pillar
device into the designated sample collection test tube, regularly record the collected
liquid volume and measure the concentration data of the corresponding nuclides, so as to
observe the adsorption and migration of nuclides in the rock pillar.
The designed research object of the whole apparatus is a complete granite core, rather
than granite mineral powder, so that the experimental data for studying the adsorption
migration and retention law of nuclides in granite fissures are more realistic. Through the
design of adjustable granite core volume, the limitation of general fixed volume rock
pillar design is broken, and different volumes of granite cores can be flexibly used for
adsorption migration experiments, which enhances the practicability of the apparatus and is beneficial for researchers to carry out research on parameter scale effects. The sealing treatment for the granite pillar is excellent in the whole device, and the treatment is divided into three steps of coating a layer of epoxy resin on the side of single fissured rock pillar firstly; then a transparent latex film is sleeved on the outer layer; and finally, the whole adsorption and migration rock pillar device is sealed and ventilated, so that the air pressure of the whole device can reach 2 MPa stably, thus achieving the purpose of sealing. The apparatus can simultaneously carry out conditional experiments and parallel experiments with different influencing factors, and the automatic data collection device can automatically collect experimental data in real time, saving labour cost. Besides, the experimental process can be repeated.
A test method using the apparatus for studying the adsorption mechanism of nuclides in
single fissure natural granite comprises following steps.
(1) Pre-treatment and sealing of rock pillars
Granite pillars are selected according to experimental requirements. At first, the granite
pillar is treated by "Brazil disk split test" to produce "single fissure"; and then it is sealed
by coating a layer of epoxy resin on the side of the single fissure rock pillar; and finally,
coating a layer of transparent latex film on its outer layer.
(2) Assembly of rock pillar device
The whole adsorption and migration rock pillar device is detachable and reassembled.
Assemble the sample rock pillars preliminarily sealed in (1) in the order of pressure
chamber base, quick connector, water permeable plate, granite pillar, O-ring, bracket,
vertical pillar, sample top cover, pressure chamber top cover, adjusting rod and adjustable
telescopic rod. The outside is connected with a gas cylinder through a gas inlet pipe; the quick connector is externally connected with a liquid supply pipe, and the synthetic groundwater in the liquid supply bottle is introduced into the quick connector by a peristaltic pump, and the flow rate is set according to the experimental requirements.
Before the introduction, a group of pressure and temperature sensors are arranged on the
liquid supply pipe.
(3) Aeration of rock pillar
To prevent overflow from the side of rock pillar when liquid is introduced into single
fissured granite pillar, connect the gas cylinder with the gas inlet pipe by controlling the
gas valve; meanwhile, open the gas valve of the gas outlet pipe to transport the gas to the
whole adsorption and migration pillar device; then, close the gas valve of the gas outlet
pipe after aeration for several minutes, and continue to introduce gas. If the barometer
reading is stable at 2 MPa, close the gas valve of the gas inlet pipe.
(4) Initial balance of rock pillar water supply
The synthetic groundwater solution is selected according to the experimental
requirements. First, determine the initial concentration and pH of each ion in the prepared
synthetic groundwater solution. Start the whole device, and preliminarily set the
peristaltic pump flow rate. Then, observe the effluent flow rate, ion concentration and pH
in the sample collection test tube at intervals, and calculate the real flow rate and stability
of synthetic groundwater flowing in the whole granite pillar. This process continues until
the effluent flow output is stable and the ion concentration and pH value are consistent
with the initial measurement results, indicating that the rock pillar water supply initially
reaches balanced state.
(5) Injection of adsorbents and tracer agents
According to the experimental requirements, adsorbents and tracer agents can be selected
independently, following the principle that adsorbents can adsorb granite pillar, and
concentration changes before and after the reaction can be detected by measuring
instruments; tracer agents hardly react with granite pillar, and is not a component of
synthetic groundwater solution, with a simple measurement method. Here, the adsorbent
takes radionuclide U as an example, and the tracer agent takes bromine ion as an
example. The concentration selection is based on the standard that the initial
concentration set by the laboratory is generally 10-100 times higher than the
corresponding concentration of this element in natural groundwater solution. Two types
of synthetic groundwater solutions (SGW1 and SGW2) are prepared, wherein SGW1
contains only bromine ion tracer agent; SGW2 contains radionuclide adsorbent and
bromine ion tracer agent. The synthetic groundwater solution introduced in step (4) is
replaced by SGW1. This process continues until the concentration of tracer bromine ion
collected by the sample collection tube is consistent with that of the initial bromine ion.
Then, the synthetic groundwater solution SGW1 is replaced by SGW2, and the process
continues until the concentration of adsorbent uranium collected by the sample collection
tube reaches 90% of the initial uranium concentration.
(6) Observation, record and measurement of the experimental data
When the peristaltic pump is started after the ventilation in step (3), observe and record
the experimental data. Firstly, record the experimental data of pressure sensor and
temperature sensor regularly, and set each sample collection test tube regularly to collect
ml effluent and then automatically transfer to the next test tube. The time setting of the
automatic fraction collector can be determined according to the seepage velocity, which can be calculated by the outflow rate of effluent. If the flow velocity is fast, the setting interval is relatively small, and vice versa. The radionuclide concentration is determined by ICP-OES instrument. The concentration of tracer agent is determined by anion chromatograph. By observing the concentration penetration curves of adsorbents and tracer agents at different times, people can directly observe the adsorption and migration changes of adsorbents on granite pillars.
After completing a complete simulation experiment, the granite pillar is flushed with
distilled water for a period of time, and the repeated contrast experiment of the same rock
pillar can be realized by repeating the last three steps, which is convenient to operate and
can verify the reliability of experimental data.
Compared with the prior art, the beneficial effects of the invention mainly have the
following aspects. (1) Because the research on adsorption and migration of nuclides on
powdered minerals is too idealistic, the migration of nuclides mainly occurs in cracks or
fractured zones of rocks in real situations. The research object of the device design is
aimed at the undisturbed fractured granite core, not the granite mineral powder, so that
the experimental data for studying the adsorption, migration and retention law of nuclides
in surrounding rock are more realistic; (2) Through the design of adjustable granite core
volume, the limitation of general fixed volume rock pillar design is broken, and
considering the economic cost problem, different volumes of granite core can be used
flexibly to study the adsorption and migration law; (3) In order to prevent the overflow of
liquid from the side of granite pillar, the three-step sealing treatment measures for granite
pillar are in place, namely, coating a layer of epoxy resin on the surface of rock pillar,
covering a layer of transparent latex film on the outer layer, and introducing gas to seal the rock pillar by air pressure; (4) In the process of simulation, the flow rate and composition of liquid can be changed according to the need, and conditional experiments and parallel experiments under different influence conditions can be carried out at the same time; (5) The experimental method is simple, easy to operate, automatic in data collection, saving labour cost, and can repeat the experimental process, and the results can be compared and analysed with high reliability.
Figure 1 is a schematic structural diagram of the apparatus for studying the adsorption
mechanism of nuclides in single fissured natural granite.
Figure 2 is a right-side view of the adsorption and migration rock pillar device.
Figure 3 is a schematic diagram of the three-dimensional pillar structure of the adsorption
and migration rock pillar device.
In figure, A- liquid supply regulating device with variable speed, B- automatic effluent
collection device, C- adsorption and migration rock pillar device; 1- liquid supply bottle,
2- synthetic groundwater solution, 3- liquid supply pipe, 4- peristaltic pump, 5- pressure
sensor, 6- temperature sensor, 7- hexagonal nut, 8- pressure chamber bottom cover, 9
organic glass cover, 10- transparent latex film, 11- water permeable plate, 12- vertical
pillar, 13- barometer, 14- quick connector, 15- gas outlet, 16- gas valve, 17- gas inlet, 18
gas cylinder, 19- vertical pillar, 20- adjustable telescopic rod, 21- quick connector, 22
adjusting rod, 23- hexagonal nut, 24- effluent pipe, 25- effluent, 26- sample collection
test tube, 27- automatic fraction collector , 28- sample lower seat, 29- sample top cover,
- granite pillar, 31- bracket, 32-0-ring, 33- pressure chamber top cover.
The present invention will be further described in detail with reference to the attached
figures and specific embodiments. The following figures are simplified schematic
diagrams illustrating the basic structure of the invention, so only the components related
to the invention are shown.
According to the invention, adsorption and migration tests of related radionuclides are
carried out based on the existing laboratories. As shown in fig.1 to fig.3, the present
invention provides a device for studying adsorption mechanism of nuclides in single
fissured natural granite, which comprises a liquid supply regulating device with variable
speed A, an adsorption and migration rock pillar device C, an automatic effluent
collection device B, a pressure 5 and temperature sensor 6, a barometer 13 and a gas
cylinder 18.
Specifically, the liquid supply regulating device with variable speed A consists of a liquid
supply bottle 1, a synthetic groundwater solution 2, a liquid supply pipe 3 and a peristaltic
pump 4. The liquid supply bottle 1 is filled with synthetic groundwater solution 2, which
is prepared with reference to the actual groundwater ion composition in the field
sampling area. There are two types of synthetic groundwater solutions (SGW1 and
SGW2), wherein SGW1 contains only bromine ion tracer agent; SGW2 contains
radionuclide adsorbent and bromine ion tracer agent. Peristaltic pump 4 is a BT100L
model with a DG10-4 pump head and a controlled flow rate of 0.21 [L/min-48 mL/min,
providing the driving force for the entire system. The synthetic groundwater solution 2 is
delivered to the adsorption and migration rock pillar device C through the liquid supply
pipe 3. The adjustable flow rate of the peristaltic pump provides variable speed conditions throughout the experiment so that the effect of different flow rate variations on the adsorption migration of radionuclides on the rock pillar can be observed.
The adsorption and migration rock pillar device C is the core area of the whole device,
including pressure chamber top cover 33, pressure chamber bottom cover 8, sample top
cover 29, sample lower seat 28, water permeable plate 11, quick connectors 14 and 21,
granite pillar 30 (containing single fissure), transparent latex film 10, organic glass cover
9, O-ring 32, bracket 31, six vertical pillars 12, four vertical pillars 9, some hexagonal
nuts 7 and 23, gas inlet 17 and outlet pipes 15, adjustable telescopic rod 20 and adjusting
rod 22. The synthetic groundwater solution 2 enters the granite pillar 30 after passing
through the quick connector 14, the sample lower seat 28 and the water permeable plate
11, and then flows into the automatic effluent collection device B after passing through
the adjusting rod 22 and the quick connector 21.
The entire adsorption and migration rock pillar device C has two main features.
(1) The volume of granite pillar 30 has a certain fluctuation space, in which the length of
rock pillar can be designed in the range of 5-12 cm, which can be realized by vertical
pillar 19, adjustable telescopic rod 20 and adjusting rod 22. The corresponding diameter
of granite pillar 30 can be designed in the range of 5-7 cm, which can be realized by
adjusting the height of bracket 31 and replacing matched sample lower seat 28, sample
top cover 29 and water permeable plate 11. This design of adjustable rock pillar volume
within a certain range breaks the limitation of general fixed volume design of rock pillar.
Since the volume of granite rock pillars 30 used for different drilling in different sites or
the same site may have certain differences, the inconsistent volume of granite rock pillars
in the later processing will cause certain problems for the entire adsorption migration rock pillar device C. In addition, improper processing will cause the granite rock pillars to be broken or improperly sealed to leak, which will cause the loss of the rock sample or the problem that the experimental device cannot be reused. Considering the economic cost, it is necessary to design the adjustable rock pillar volume.
(2) The sealing treatment measures of granite pillar 30 in the whole device are excellent,
and the purpose that granite pillar does not leak liquid is realized through three steps.
Firstly, a layer of epoxy resin with a thickness of 1-3 mm is coated on the side of the
single fissured rock pillar 30 to prevent liquid from flowing out laterally from the rock
pillar; secondly, a layer of transparent latex film with a thickness of 1 mm is sleeved on
the outer layer, which plays the role of further water insulation; finally, in order to make
the sealing effect better, the gas cylinder 18 is connected with the gas inlet 17 by
controlling the gas valve 16, so that the gas is delivered to the whole adsorption and
migration rock pillar device C, and the pressure of the whole device reaches 2 MPa by
reading the barometer 13 . Through these three steps, the sealing effect of single fissure
granite pillar 30 is optimized, and the error of experimental results is reduced.
The automatic effluent collection device B includes effluent pipe 24, effluent 25, sample
collection test tube 26 and automatic fraction collector 27. automatic fraction collector 27
is SBS-100, which can adopt the sampling range of 1 s-200 h at regular time or 1 drop
9999 drops at fixed drop, with 100 sample collection test tubes, each with a maximum
capacity of 12ml. The function of the device is to automatically collect the liquid flowing
out of the adsorption and migration rock pillar device C into the designated sample
collection test tube 26 and control the test tube to automatically change the test tube after
collecting 5 ml of effluent.
The pressure sensor 5 and the temperature sensor 6 can monitor the temperature and
pressure of the synthetic groundwater 2 in the liquid supply pipe 3 in real time before
flowing into the adsorption and migration rock pillar device C, and can provide both data
through real-time recording, thus providing a certain theoretical basis and basic data
support for the subsequent experimental data processing and analysis of the observed
radionuclide concentration or the use of relevant models to simulate the adsorption and
migration law of nuclides in a single fissured rock pillar.
In the invention, the whole adsorption and migration rock pillar device is a cylinder with
a length of 21 cm and a diameter of 14 cm. The shell is made of stainless steel, which
includes pressure chamber top cover 33, pressure chamber bottom cover 8, sample top
cover 29, sample lower seat 28, six vertical pillars 12, four vertical pillars 19, several
hexagonal nuts 7 and 23, adjustable telescopic rod 20 and quick connector 14 and 21.
Among them, the thickness of pressure chamber top cover, bottom cover, sample top
cover and lower seat are all 2 cm, and six vertical pillars 12 are 21 cm long and 1 cm in
inner diameter. The four vertical pillars 19 are 9 cm long and 0.5 cm in inner diameter.
The external diameter of a plurality of hexagonal nuts 7 is lcm, and the internal diameter
and thickness are both 0.5cm. Adjustable telescopic rod 20 is 13 cm long and 2 cm in
inner diameter; the quick connector 14 or 21 has a length of 1 cm and an outer diameter
of 0.25 cm. The inner structure of the device comprises an O-ring 32, a bracket 31, an
adjusting rod 22, a water permeable plate 11, and gas inlet and outlet pipes 17 and 15. 0
ring 32 is made of plexiglass with an outer diameter of 9 cm, an inner diameter of 7 cm
and a thickness of 1 cm. The material of the bracket 31 is plexiglass, with a length of 12.5
cm, and the height decreases with the increase of the diameter of the granite pillar 30, ranging from 0 to 1 cm. The thickness of that permeable plate 11 is 0.3cm. The adjusting rod 22 has a length of 11 cm and an inner diameter of 0.25 cm. The inner diameter of the liquid supply pipe 3 and the effluent pipe 24 of the whole experimental device is 0.1 cm.
In order to make the radionuclide fully contact with the single fissure interface of granite
pillar 30, the flow rate of peristaltic pump 4 can be set to 0.3 ml/h. The automatic fraction
collector 27 automatically switch to that next test tube every time the capacity of the test
tube 26 collecting samples is 5ml.
A test method using the device for studying the adsorption mechanism of nuclides in
single fissure natural granite comprises the following steps.
(1) Pre-treatment and sealing of rock pillars
Granite pillars 30 are selected according to experimental requirements. A standard granite
pillar 10 cm long and 5 cm in diameter is used here as an example. In order to produce a
"single fracture" in the granite core, the "Brazil disk split test" is used to pre-process the
single fracture. And then it is sealed by coating a layer of 1-3 mm thick epoxy resin on
the side of the single fissure rock pillar 30; and finally, coating a layer of 1 mm thick
transparent latex film on its outer layer.
(2) Assembly of rock pillar device
The whole adsorption and migration rock pillar device C is detachable and reassembled.
Assemble the sample rock pillars 30 preliminarily sealed in (1) in the order of pressure
chamber base 8, quick connector 14, water permeable plate 11, granite pillar 30, O-ring
31, bracket 31, vertical pillar 12, sample top cover 29, pressure chamber top cover 33,
adjusting rod 32 and adjustable telescopic rod 20, vertical pillar 19 and quick connector
21. The outside is connected with a gas cylinder 18 through a gas inlet pipe 17, wherein the gas is selected according to the experimental requirements, and the argon gas is selected here; the quick connector 14 is externally connected with a liquid supply pipe 3, and the synthetic groundwater 2 in the liquid supply bottle 1 is introduced into the quick connector 14 by a peristaltic pump 4, and the flow rate is set as 0.3 ml/h here according to the experimental requirements. Before the introduction, a group of pressure 5 and temperature 6 sensors are arranged on the liquid supply pipe 3.
(3) Aeration of rock pillar
To prevent overflow from the side of rock pillar when liquid is introduced into single
fissured granite pillar 30, connect the gas cylinder 18 with the gas inlet pipe 17 by
controlling the gas valve 16; meanwhile, open the gas valve of the gas outlet pipe 15 to
transport the gas to the whole adsorption and migration pillar device C; then, close the
gas valve of the gas outlet pipe 15 after aeration for several minutes, and continue to
introduce gas. Control the air pressure of the whole device at about 2 MPa through the
reading of the barometer 13 and observe the air tightness. If the reading of the barometer
13 stabilizes at 2 MPa, close the air valve 16.
(4) Initial balance of rock pillar water supply
The synthetic groundwater solution 2 is selected according to the experimental
requirements. Here, it is prepared and synthesized based on the ionic components of
groundwater at a depth of 600 m in a borehole in a certain area of Northwest China. First,
determine the initial concentration and pH of each ion in the prepared synthetic
groundwater solution 2. Start the whole device, and preliminarily set the peristaltic pump
flow rate as 03. ml/h. The flow rate in the whole process is very slow, and the air bubbles
enclosed in the granite rock pillar 30 can be discharged. Then, observe the effluent 25 flow rate, ion concentration and pH in the sample collection test tube 26 at intervals, and calculate the real flow rate and stability of synthetic groundwater 2flowing in the whole granite pillar 30. This process continues until the effluent 25 flow output is stable and the ion concentration and pH value are consistent with the initial measurement results, indicating that the rock pillar water supply initially reaches balanced state.
(5) Injection of adsorbents and tracer agents
According to the experimental requirements, adsorbents and tracer agents can be selected
independently, following the principle that adsorbents can adsorb granite pillar 30, and
concentration changes before and after the reaction can be detected by measuring
instruments; tracer agents hardly react with granite pillar 30, and is not a component of
synthetic groundwater solution, with a simple measurement method. Here, the adsorbent
takes radionuclide U as an example. The concentration selection is based on the standard
that the initial concentration set by the laboratory is generally 10-100 times higher than
the corresponding concentration of this element in natural groundwater solution. Thereby,
set the initial concentration of U to 2.0*10-5 mol/L; and the tracer agent takes bromine ion
as an example, with initial concentration of 1.0*10-2 mol/L. Two types of synthetic
groundwater solutions 2 (SGW1 and SGW 2) are prepared, wherein SGW1 contains only
bromine ion tracer agent; SGW2 contains radionuclide adsorbent and bromine ion tracer
agent. The synthetic groundwater solution introduced in step (4) is replaced by SGW1.
This process continues until the concentration of tracer bromine ion collected by the
sample collection tube 26 is consistent with that of the initial bromine ion. Then, the
synthetic groundwater solution SGW1 is replaced by SGW2, and the process continues until the concentration of adsorbent uranium collected by the sample collection tube 26 reaches 90% of the initial uranium concentration.
(6) Observation, record and measurement of the experimental data
When the peristaltic pump is started after the ventilation in step (3), observe and record
the experimental data. Firstly, record the experimental data of pressure sensor 5 and
temperature sensor 6 regularly, and set each sample collection test tube 26 regularly to
collect 5 ml effluent 25 and then automatically transfer to the next test tube. The time
setting of the automatic fraction collector 27 can be determined according to the seepage
velocity, which can be calculated by the outflow rate of effluent 25. If the flow velocity is
fast, the setting interval is relatively small, and vice versa. Since the replacement time of
the synthetic underground aqueous solutions SGW1 and SGW2 in step (5) is based on the
measured concentrations of the tracer and the adsorbent in the effluent 25, it is necessary
to monitor the concentrations of both in real time. The radionuclide concentration is
determined by ICP-OES instrument. The concentration of tracer agent is determined by
anion chromatograph. By observing the concentration penetration curves of adsorbents
and tracer agents at different times, people can directly observe the adsorption and
migration changes of adsorbents on granite pillars 30. For the entire device for the same
granite rock pillar 30, the same set of experiments needs to be repeated 3 times in order to
ensure the reliability of the experimental results.
Claims (7)
1. An apparatus for studying the adsorption mechanism of nuclides in single fissure
natural granite, characterized by comprising a liquid supply regulating device with
variable speed, an adsorption and migration rock pillar device, an automatic effluent
collection device, a pressure and temperature sensor, a barometer and a gas cylinder.
Specifically, the liquid supply regulating device with variable speed consists of a liquid
supply bottle, a synthetic groundwater solution, a liquid supply pipe and a peristaltic
pump. The liquid supply bottle is filled with synthetic groundwater solution, which is
prepared with reference to the actual groundwater ion composition in the field sampling
area. The peristaltic pump provides the driving force for the whole system, and the flow
rate can be adjusted as required. The synthetic groundwater solution is delivered to the
adsorption and migration rock pillar device through the liquid supply pipe.
The adsorption and migration rock pillar device is the core area of the whole device,
including pressure chamber top cover, pressure chamber bottom cover, sample top cover,
sample lower seat, water permeable plate, quick connector, granite pillar (containing
single fissure), transparent latex film, organic glass cover, 0-ring, bracket, vertical pillar,
several hexagonal nuts, gas inlet and outlet pipes, adjustable telescopic rod and adjusting
rod. The synthetic groundwater solution enters the granite pillar after passing through the
quick connector, the sample lower seat and the water permeable plate, and then flows into
the automatic effluent collection device after passing through the adjusting rod and the
quick connector.
The automatic effluent collection device includes effluent pipe, effluent, sample
collection test tube and automatic fraction collector . The function of the device is to automatically collect the liquid flowing out of the adsorption and migration rock pillar device into the designated sample collection test tube, regularly record the collected liquid volume and measure the concentration data of the corresponding nuclides, so as to observe the adsorption and migration of nuclides in the rock pillar.
2. The apparatus for studying the adsorption mechanism of nuclides in single fissure
natural granite as stated in Claim 1, characterized in that the designed research object of
the whole apparatus is a complete granite core, rather than granite mineral powder, so
that the experimental data for studying the adsorption migration and retention law of
nuclides in granite fissures are more realistic.
3. The apparatus for studying the adsorption mechanism of nuclides in single fissure
natural granite as stated in Claim 1, characterized in that through the design of adjustable
granite core volume, the limitation of general fixed volume rock pillar design is broken,
and different volumes of granite cores can be flexibly used for adsorption migration
experiments, which enhances the practicability of the apparatus and is beneficial for
researchers to carry out research on parameter scale effects.
4. The apparatus for studying the adsorption mechanism of nuclides in single fissure
natural granite as stated in Claim 1, characterized in that the sealing treatment for the
granite pillar is excellent in the whole device, and the treatment is divided into three steps
of coating a layer of epoxy resin on the side of single fissured rock pillar firstly; then a
transparent latex film is sleeved on the outer layer; and finally, the whole adsorption and
migration rock pillar device is sealed and ventilated, so that the air pressure of the whole
device can reach 2 MPa stably, thus achieving the purpose of sealing.
5. The apparatus for studying the adsorption mechanism of nuclides in single fissure
natural granite as stated in Claim 1, characterized in that the device can simultaneously
carry out conditional experiments and parallel experiments with different influencing
factors, and the automatic data collection device can automatically collect experimental
data in real time, saving labour cost. Besides, the experimental process can be repeated.
6. A test method using the apparatus for studying the adsorption mechanism of nuclides
in single fissure natural granite as stated in Claim 1, characterized in that the method
comprises following steps.
(1) Pre-treatment and sealing of rock pillars
Granite pillars are selected according to experimental requirements. At first, the granite
pillar is treated by "Brazil disk split test" to produce "single fissure"; and then it is sealed
by coating a layer of epoxy resin on the side of the single fissure rock pillar; and finally,
coating a layer of transparent latex film on its outer layer.
(2) Assembly of rock pillar device
The whole adsorption and migration rock pillar device is detachable and reassembled.
Assemble the sample rock pillars preliminarily sealed in (1) in the order of pressure
chamber base, quick connector, water permeable plate, granite pillar, O-ring, bracket,
vertical pillar, sample top cover, pressure chamber top cover, adjusting rod and adjustable
telescopic rod. The outside is connected with a gas cylinder through a gas inlet pipe; the
quick connector is externally connected with a liquid supply pipe, and the synthetic
groundwater in the liquid supply bottle is introduced into the quick connector by a
peristaltic pump, and the flow rate is set according to the experimental requirements.
Before the introduction, a group of pressure and temperature sensors are arranged on the
liquid supply pipe.
(3) Aeration of rock pillar
To prevent overflow from the side of rock pillar when liquid is introduced into single
fissured granite pillar, connect the gas cylinder with the gas inlet pipe by controlling the
gas valve; meanwhile, open the gas valve of the gas outlet pipe to transport the gas to the
whole adsorption and migration pillar device; then, close the gas valve of the gas outlet
pipe after aeration for several minutes, and continue to introduce gas. If the barometer
reading is stable at 2 MPa, close the gas valve of the gas inlet pipe.
(4) Initial balance of rock pillar water supply
The synthetic groundwater solution is selected according to the experimental
requirements. First, determine the initial concentration and pH of each ion in the prepared
synthetic groundwater solution. Start the whole device, and preliminarily set the
peristaltic pump flow rate. Then, observe the effluent flow rate, ion concentration and pH
in the sample collection test tube at intervals, and calculate the real flow rate and stability
of synthetic groundwater flowing in the whole granite pillar. This process continues until
the effluent flow output is stable and the ion concentration and pH value are consistent
with the initial measurement results, indicating that the rock pillar water supply initially
reaches balanced state.
(5) Injection of adsorbents and tracer agents
According to the experimental requirements, adsorbents and tracer agents can be selected
independently, following the principle that adsorbents can adsorb granite pillar, and
concentration changes before and after the reaction can be detected by measuring instruments; tracer agents hardly react with granite pillar, and is not a component of synthetic groundwater solution, with a simple measurement method. Here, the adsorbent takes radionuclide U as an example, and the tracer agent takes bromine ion as an example. The concentration selection is based on the standard that the initial concentration set by the laboratory is generally 10-100 times higher than the corresponding concentration of this element in natural groundwater solution. Two types of synthetic groundwater solutions (SGW1 and SGW 2) are prepared, wherein SGW1 contains only bromine ion tracer agent; SGW2 contains radionuclide adsorbent and bromine ion tracer agent. The synthetic groundwater solution introduced in step (4) is replaced by SGW1. This process continues until the concentration of tracer bromine ion collected by the sample collection tube is consistent with that of the initial bromine ion.
Then, the synthetic groundwater solution SGW1 is replaced by SGW2, and the process
continues until the concentration of adsorbent uranium collected by the sample collection
tube reaches 90% of the initial uranium concentration.
(6) Observation, record and measurement of the experimental data
When the peristaltic pump is started after the ventilation in step (3), observe and record
the experimental data. Firstly, record the experimental data of pressure sensor and
temperature sensor regularly, and set each sample collection test tube regularly to collect
ml effluent and then automatically transfer to the next test tube. The time setting of the
automatic fraction collector can be determined according to the seepage velocity, which
can be calculated by the outflow rate of effluent. If the flow velocity is fast, the setting
interval is relatively small, and vice versa. The radionuclide concentration is determined
by ICP-OES instrument. The concentration of tracer agent is determined by anion chromatograph. By observing the concentration penetration curves of adsorbents and tracer agents at different times, people can directly observe the adsorption and migration changes of adsorbents on granite pillars.
7. The test method using the apparatus for studying the adsorption mechanism of nuclides
in single fissure natural granite as stated in Claim 6, characterized in that after completing
a complete simulation experiment, the granite pillar is flushed with distilled water for a
period of time, and the repeated contrast experiment of the same rock pillar can be
realized by repeating the last three steps, which is convenient to operate and can verify
the reliability of experimental data.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU2021102791A AU2021102791A4 (en) | 2021-05-24 | 2021-05-24 | Apparatus for Studying the Adsorption Mechanism of Nuclides in Single Fissure Natural Granite |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU2021102791A AU2021102791A4 (en) | 2021-05-24 | 2021-05-24 | Apparatus for Studying the Adsorption Mechanism of Nuclides in Single Fissure Natural Granite |
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ID=76785328
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114722608A (en) * | 2022-04-12 | 2022-07-08 | 核工业北京地质研究院 | Simulation method and system for decay and migration of nuclide in fissured medium |
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2021
- 2021-05-24 AU AU2021102791A patent/AU2021102791A4/en not_active Ceased
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114722608A (en) * | 2022-04-12 | 2022-07-08 | 核工业北京地质研究院 | Simulation method and system for decay and migration of nuclide in fissured medium |
| CN114722608B (en) * | 2022-04-12 | 2022-11-29 | 核工业北京地质研究院 | Simulation method and system for decay and migration of nuclide in fissure medium |
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