A pretreatment device for analyzing carbon-14 activity in high-activity tritium water

Abstract

The present invention specifically relates to a C-14 activity analysis pretreatment device in high-activity tritium water, including an ultraviolet lamp, an oxidation reactor, a gas carrier device, and a tritium removal and C-14 absorption device; an oxidant inlet and a sample inlet are respectively arranged on the upper part of one side surface of the oxidation reactor, and the oxidant and the high-tritium water sample enter the oxidation reactor through the oxidant inlet and the sample inlet respectively; an ultraviolet lamp is arranged inside the oxidation reactor, the top of the oxidation reactor is connected to the gas carrier device, and a gas outlet is arranged on the upper part of the other side of the oxidation reactor, and the gas outlet of the oxidation reactor is connected to the tritium removal and C-14 absorption device. The C-14 activity analysis pretreatment device in high-activity tritium water of the present invention completely removes tritium in the sample, collects C-14 in the sample, and avoids the influence of tritium pulse accumulation on C-14 counting during sample analysis.

Description

Technical Field

[0001] The invention relates to the technical field of tritium water analysis, in particular to a pretreatment device for carbon-14 activity analysis in high-activity tritium water. Background Art

[0002] C-14 in heavy water reactor nuclear power plants is mainly produced by the reaction 17O(n,α)→14C. Due to the differences in the chemical properties of various systems in heavy water reactor nuclear power plants, C-14 exists in different forms. For example, C-14 in the moderator system is mainly in the form of inorganic carbon, and C-14 in the coolant system is mainly in the form of low-molecular organic matter such as volatile gases, methanol, formaldehyde and formic acid.

[0003] Since heavy water is used as the moderator and coolant in heavy water reactor nuclear power plants, the activity of tritium in heavy water is several orders of magnitude higher than that of C-14. When using a liquid scintillation counter to analyze the activity of C-14 in high-tritium water, the pulse accumulation of tritium in the sample will enter the C-14 counting range (18.6-156keV), resulting in a higher analysis data for C-14. Summary of the invention

[0004] Based on this, it is necessary to provide a pretreatment device for carbon-14 activity analysis in high-activity tritium water to address the problem of the influence of tritium in the sample on the C-14 analysis data count during the C-14 activity analysis in high-activity tritium water. The device completely removes tritium from the sample, collects C-14 in the sample, and avoids the influence of tritium pulse accumulation on C-14 counts during sample analysis.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A pretreatment device for analyzing C-14 activity in high-activity tritium water, comprising an ultraviolet lamp, an oxidation reactor, a carrier gas device, and a tritium removal and C-14 absorption device;

[0007] An oxidant inlet and a sample inlet are respectively arranged on one side of the oxidation reactor, and the oxidant and the tritium-rich water sample enter the oxidation reactor through the oxidant inlet and the sample inlet respectively;

[0008] An ultraviolet lamp is arranged inside the oxidation reactor, the top of the oxidation reactor is connected to a gas carrier device, a gas outlet is arranged on the upper part of the other side of the oxidation reactor, and the gas outlet of the oxidation reactor is connected to a detritus removal and C-14 absorption device;

[0009] The high-tritiated water sample and the oxidant react under the irradiation of ultraviolet lamp, and the generated gas flows into the detritiation and C-14 absorption device through the carrier gas and the gas outlet. The detritiation and C-14 absorption device completely eliminates the tritium in the high-tritiated water sample and collects the C-14 in the high-tritiated water sample.

[0010] Working principle: The oxidant and high-tritiated water sample enter the oxidation reactor through the oxidant inlet and the sample inlet respectively. Under the irradiation of ultraviolet lamp, the high-tritiated water sample and the oxidant react, and the C-14 in organic and inorganic forms in the high-tritiated water sample is converted into CO2 and flows into the detritiated and C-14 absorption device through the gas outlet through the carrier gas. The detritiated and C-14 absorption device completely eliminates the tritium in the high-tritiated water sample and collects the C-14 in the high-tritiated water sample, avoiding the influence of tritium pulse accumulation on C-14 counts during the analysis of the high-tritiated water sample.

[0011] Furthermore, a waste valve V is provided at the bottom of the oxidation reactor, and the high-tritium water sample and the oxidant react under the irradiation of the ultraviolet lamp, and the generated liquid is discharged through the waste valve.

[0012] Furthermore, the oxidant enters the oxidation reactor 3 through the oxidant inlet through a pipeline, an oxidant isolation valve is arranged on the pipeline through which the oxidant enters the oxidation reactor through the oxidant inlet, the high-tritiated water sample enters the oxidation reactor through the sample inlet through a pipeline, and an injection isolation valve is arranged on the pipeline through which the high-tritiated water sample enters the oxidation reactor through the sample inlet.

[0013] Furthermore, the gas carrier device includes a diffusion head, a gas carrier pipe, a flow meter and a gas carrier control valve. The gas carrier pipe is provided with a gas carrier control valve and a flow meter in sequence from bottom to top at one end away from the top of the oxidation reactor. The gas carrier pipe enters the oxidation reactor at one end close to the top of the oxidation reactor and is connected to the diffusion head. The diffusion head is arranged inside the oxidation reactor, and the carrier gas enters the interior of the oxidation reactor via the diffusion head through the gas carrier pipe.

[0014] Furthermore, the carrier gas is N2; the oxidant is H2O2 or H3PO4+Na2S2O8.

[0015] Furthermore, the detritiation and C-14 absorption device includes a primary acid absorption device, a secondary acid absorption device, and an alkali absorption device, and the gas outlet of the oxidation reactor is connected to the primary acid absorption device, the secondary acid absorption device and the alkali absorption device in sequence.

[0016] Furthermore, the primary acid absorption device is a first glass bubbler filled with acid absorption liquid, the secondary acid absorption device is a second glass bubbler filled with acid absorption liquid, and the alkali absorption device is a glass absorption bottle filled with alkali absorption liquid.

[0017] Furthermore, gas inlets are arranged on the tops of the first glass bubbler and the second glass bubbler, and gas outlets are arranged on the upper sides of the first glass bubbler and the second glass bubbler; the gas outlet of the oxidation reactor is connected to the gas inlet of the first glass bubbler through a connecting hose, the gas outlet of the first glass bubbler is connected to the gas inlet of the second glass bubbler through a silicone tube, and the gas outlet of the second glass bubbler is connected to the glass absorption bottle pipeline.

[0018] Furthermore, a quick connector is provided on the connecting hose connecting the gas outlet of the oxidation reactor and the gas inlet of the first glass bubbler.

[0019] Furthermore, the acid absorption liquid of the primary acid absorption device and the secondary acid absorption device are both H2SO4; the alkali absorption liquid of the alkali absorption device is NaOH.

[0020] Furthermore, the C-14 activity analysis pretreatment device in high-activity tritium water also includes a waste liquid absorption device, and the waste liquid absorption device is connected to the alkali absorption device pipeline.

[0021] Furthermore, a gas inlet is arranged at the top of the glass absorption bottle, a gas outlet is arranged at the upper side of the glass absorption bottle, the gas outlet of the second glass bubbler is connected to the gas inlet pipeline of the glass absorption bottle, and the gas outlet of the glass absorption bottle is connected to the glass colorimetric tube pipeline.

[0022] Beneficial technical effects of the present invention:

[0023] The C-14 activity analysis pretreatment device in high-activity tritium water of the present invention can not only avoid the influence of high-tritium pulse accumulation on C-14 counting, but also remove the influence of β and γ nuclides in the sample with energy in the range of 18.6-156keV, thereby ensuring the accuracy of C-14 measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the structure of the pretreatment device for analyzing the activity of C-14 in high-activity tritium water according to the present invention.

[0025] In the figure, 1. diffusion head; 2. ultraviolet lamp; 3. oxidation reactor; 4. first glass bubbler; 5. second glass bubbler; 6. glass absorption bottle; 7. glass colorimetric tube; 8. carrier gas tube; 9. connecting hose; 10. silicone tube; 11. oxidant isolation valve; 12. injection isolation valve; 13. waste valve; 14. carrier gas control valve; 15. quick connector; 16. flow meter. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0027] See also Figure 1 The present invention provides a pretreatment device for analyzing the activity of C-14 in high-activity tritium water, comprising an ultraviolet lamp 2, an oxidation reactor 3, a carrier gas device, a tritium removal and C-14 absorption device, and a waste liquid absorption device.

[0028] An oxidant inlet and a sample inlet are respectively arranged on the middle of one side surface of the oxidation reactor 3, and the oxidant and the high-tritium water sample enter the oxidation reactor 3 through the oxidant inlet and the sample inlet respectively.

[0029] An ultraviolet lamp 2 is arranged inside the oxidation reactor 3, the top of the oxidation reactor 3 is connected to a gas carrier device, a gas outlet is arranged on the upper part of the other side of the oxidation reactor 3, and the gas outlet of the oxidation reactor 3 is connected to a detritus removal and C-14 absorption device.

[0030] The high-tritiated water sample and the oxidant react under the irradiation of the ultraviolet lamp 2, and the generated gas flows into the detritiation and C-14 absorption device through the carrier gas and the gas outlet. The detritiation and C-14 absorption device completely eliminates the tritium in the high-tritiated water sample and collects the C-14 in the high-tritiated water sample.

[0031] A waste valve 13 is arranged at the bottom of the oxidation reactor 3 . The high-tritium water sample and the oxidant react under the irradiation of the ultraviolet lamp 2 , and the generated liquid is discharged through the waste valve 13 .

[0032] The oxidant enters the oxidation reactor 3 through the oxidant inlet through a pipeline, and an oxidant isolation valve 11 is arranged on the pipeline where the oxidant enters the oxidation reactor through the oxidant inlet. The high-tritiated water sample enters the oxidation reactor 3 through the sample inlet through a pipeline, and an injection isolation valve 12 is arranged on the pipeline where the high-tritiated water sample enters the oxidation reactor through the sample inlet.

[0033] The gas carrier device includes a diffusion head 1, a gas carrier tube 8, a flow meter 16 and a gas carrier control valve 14. The gas carrier tube 8 is provided with a gas carrier control valve 14 and a flow meter 16 in sequence from bottom to top at one end away from the top of the oxidation reactor 3. The gas carrier tube 8 enters the oxidation reactor 3 at one end close to the top of the oxidation reactor 3 and is connected to the diffusion head 1. The diffusion head 1 is arranged inside the oxidation reactor 3, and the carrier gas enters the oxidation reactor 3 via the diffusion head 1 through the gas carrier tube 8.

[0034] The carrier gas is 10 mL / min N2; the oxidant is 1 wt% H2O2 or H3PO4+Na2SO8.

[0035] The detritium and C-14 absorption device comprises a primary acid absorption device, a secondary acid absorption device, and an alkali absorption device. The gas outlet of the oxidation reactor is connected to the primary acid absorption device, the secondary acid absorption device, and the alkali absorption device in sequence.

[0036] The organic and inorganic forms of C-14 in the high-tritium water sample are converted into CO2 and flow into the primary acid absorption device, the secondary acid absorption device and the alkali absorption device in sequence through the carrier gas through the gas outlet. The primary acid absorption device and the secondary acid absorption device remove most of the H-3 in the gas. The gas after acid absorption is then absorbed by the alkali solution to absorb the CO2 therein. Finally, the C-14 activity in the sample is calculated by measuring the C-14 activity in the alkali absorption liquid.

[0037] The primary acid absorption device is a first glass bubbler 4 filled with acid absorption liquid, the secondary acid absorption device is a second glass bubbler 5 filled with acid absorption liquid, and the alkali absorption device is a glass absorption bottle 6 filled with alkali absorption liquid.

[0038] The C-14 in organic and inorganic forms in the high-tritiated water sample is converted into CO2 and flows into the primary acid absorption device, the secondary acid absorption device and the alkali absorption device in sequence through the carrier gas through the gas outlet. The acid absorption liquid of the primary acid absorption device and the secondary acid absorption device removes most of the H-3 in the gas. The gas absorbed by the acid absorption liquid then passes through the alkali absorption liquid of the alkali absorption device to absorb the CO2 therein. Finally, the C-14 activity in the high-tritiated water sample is calculated by measuring the C-14 activity in the alkali absorption liquid.

[0039] The first glass bubbler 4 and the second glass bubbler 5 are both provided with a gas inlet at the top, and the first glass bubbler 4 and the second glass bubbler 5 are both provided with a gas outlet at the upper side; the gas outlet of the oxidation reactor 3 is connected to the gas inlet of the first glass bubbler 4 through a connecting hose 9, the gas outlet of the first glass bubbler 4 is connected to the gas inlet of the second glass bubbler 5 through a silicone tube 10, and the gas outlet of the second glass bubbler 5 is connected to the glass absorption bottle 6 pipeline.

[0040] A quick connector 15 is provided on the connecting hose 9 connecting the gas outlet of the oxidation reactor 3 and the gas inlet of the first glass bubbler 4 .

[0041] The acid absorption liquid of the first-stage acid absorption device and the second-stage acid absorption device is 0.4 mol / L H2SO4; the alkali absorption liquid of the alkali absorption device is 0.2 mol / L NaOH.

[0042] The waste liquid absorption device is connected to the alkali absorption device pipeline, and the waste liquid absorption device is a glass colorimetric tube 7 filled with water.

[0043] The first glass bubbler 4 and the second glass bubbler 5 are both 50mL glass bubblers, the glass colorimetric tube is 50mL, the carrier gas tube 8 is a 3 / 8-inch stainless steel tube, the oxidant isolation valve 11 and the injection isolation valve 12 are both 3 / 8-inch check valves, the connecting hose 9 is a 4mm outer diameter hose, and the quick connector 15 is a PU-4mm gas line quick connector; the glass connecting ports of the oxidation reactor 3, the first glass bubbler 4, the second glass bubbler 5, the glass absorption bottle 6 and the glass colorimetric tube 7 are all connected by 10mm diameter silicone tubes, the flow meter 16 is a DFG-6T gas flow meter, and the carrier gas control valve 14 is a Lanto-R01316L stainless steel pressure reducing valve.

[0044] The gas outlet of the first glass bubbler 4 is connected to the gas inlet of the second glass bubbler 5 through a 10 mm diameter silicone tube, the gas outlet of the second glass bubbler 5 is connected to the gas inlet of the glass absorption bottle 6 through a 10 mm diameter silicone tube, the gas outlet of the glass absorption bottle 6 is connected to the glass colorimetric tube 7 through a 10 mm diameter silicone tube, the oxidant enters the oxidation reactor 3 through the oxidant inlet through the 10 mm diameter silicone tube, and the high-tritium water sample enters the oxidation reactor 3 through the sample inlet through the 10 mm diameter silicone tube.

[0045] The C-14 activity analysis pretreatment device for high-activity tritium water of the present invention comprises the following steps:

[0046] 1. The high-purity nitrogen cylinder uses a 1 / 4-inch stainless steel park to connect the pressure reducing valve and the float flowmeter, and uses a 4mm outer diameter hose and a 4mm quick connector to quickly insert the gas line. Figure 1 The device is connected to the pretreatment device for analyzing the activity of C-14 in high-activity tritium water of the present invention.

[0047] 2. Add 50 mL of 0.4 mol / L sulfuric acid solution into the 50 mL first glass bubbler 4 and the second glass bubbler 5 respectively.

[0048] 3. Add 50 mL of 0.2 mol / L sodium hydroxide solution into the 50 mL glass absorption bottle 6.

[0049] 4. Add 50 mL of deionized water into the 50 mL glass colorimetric tube 7.

[0050] 5. Place the 50mL first glass bubbler 4, the second glass bubbler 5, the glass absorption bottle 6 and the glass colorimetric tube 7 in accordance with Figure 1 The glass components were connected by silicone tubes with a diameter of 10 mm.

[0051] 6. Load the high-tritiated water sample and oxidant into the oxidation reactor 3 in a quantitative manner, close the oxidant isolation valve 11 and the injection isolation valve 12, and check the connection and seal of each glass component to confirm that there is no leakage point.

[0052] 7. Turn on the power of the UV lamp 2 and the carrier gas control valve 14, adjust the flow meter 16, control the bubbling flow rate to 8-9 mL / min, and after continuous slow bubbling for 10 minutes, turn off the UV lamp 2 and the carrier gas control valve 14.

[0053] 8. Remove the 50mL glass absorption bottle 6 and take out the alkaline absorption liquid.

[0054] 9. At the same time, use the same method to treat deionized water as a comparison blank.

[0055] 10. Take the alkaline absorption liquid as a sample and measure the C-14 activity in the alkaline absorption liquid using a liquid scintillation counter.

[0056] 11. Calculate the C-14 activity in the high tritium sample according to the formula.

[0057] The C-14 activity analysis pretreatment device in high-activity tritium water of the present invention can not only avoid the influence of high-tritium pulse accumulation on C-14 counting, but also remove the influence of β and γ nuclides in the sample with energy in the range of 18.6-156keV, thereby ensuring the accuracy of C-14 measurement.

[0058] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A pretreatment device for analyzing C-14 activity in high-activity tritium water, characterized in that: The invention comprises an ultraviolet lamp (2), an oxidation reactor (3), a gas carrier device, and a tritium removal and C-14 absorption device; an oxidant inlet and a sample inlet are respectively arranged on the upper part of one side surface of the oxidation reactor (3), and the oxidant and the high-tritium water sample enter the oxidation reactor (3) through the oxidant inlet and the sample inlet respectively; an ultraviolet lamp (2) is arranged inside the oxidation reactor (3), the top of the oxidation reactor (3) is connected to the gas carrier device, and a gas outlet is arranged on the upper part of the other side surface of the oxidation reactor (3), and the gas outlet of the oxidation reactor (3) is connected to the tritium removal and C-14 absorption device; the high-tritium water sample and the oxidant react under the irradiation of the ultraviolet lamp (2), and the generated gas flows into the tritium removal and C-14 absorption device through the gas outlet through the carrier gas, and the tritium in the high-tritium water sample is completely eliminated and the C-14 in the high-tritium water sample is collected by the tritium removal and C-14 absorption device.

2. The C-14 activity analysis pretreatment device in high-activity tritium water according to claim 1, characterized in that: A waste valve (13) is arranged at the bottom of the oxidation reactor (3); the high-tritium water sample and the oxidant react under the irradiation of the ultraviolet lamp (2), and the generated liquid is discharged through the waste valve (13).

3. The C-14 activity analysis pretreatment device in high-activity tritium water according to claim 1, characterized in that: The oxidant enters the oxidation reactor (3) through the oxidant inlet via a pipeline, an oxidant isolation valve (11) is arranged on the pipeline where the oxidant enters the oxidation reactor through the oxidant inlet, the high-tritiated water sample enters the oxidation reactor (3) through the sample inlet via a pipeline, and an injection isolation valve (12) is arranged on the pipeline where the high-tritiated water sample enters the oxidation reactor through the sample inlet.

4. The C-14 activity analysis pretreatment device in high-activity tritium water according to claim 1, characterized in that: The gas carrier device comprises a diffusion head (1), a gas carrier pipe (8), a flow meter (16) and a gas carrier control valve (14); the gas carrier pipe (8) is provided with a gas carrier control valve (14) and a flow meter (16) in sequence from bottom to top at one end away from the top of the oxidation reactor (3); the gas carrier pipe (8) enters the oxidation reactor (3) at one end close to the top of the oxidation reactor (3) and is connected to the diffusion head (1); the diffusion head (1) is arranged inside the oxidation reactor (3); and the carrier gas enters the inside of the oxidation reactor (3) via the diffusion head (1) through the gas carrier pipe (8).

5. The C-14 activity analysis pretreatment device in high-activity tritium water according to claim 1, characterized in that: The carrier gas is N2; the oxidant is H2O2 or H2PO4+Na2PO4.

6. The C-14 activity analysis pretreatment device in high-activity tritium water according to any one of claims 1 to 5, characterized in that: The detritium and C-14 absorption device comprises a primary acid absorption device, a secondary acid absorption device and an alkali absorption device, and the gas outlet of the oxidation reactor is connected to the primary acid absorption device, the secondary acid absorption device and the alkali absorption device in sequence.

7. The C-14 activity analysis pretreatment device in high-activity tritium water according to claim 6, characterized in that: The primary acid absorption device is a first glass bubbler (4) filled with acid absorption liquid, the secondary acid absorption device is a second glass bubbler (5) filled with acid absorption liquid, and the alkali absorption device is a glass absorption bottle (6) filled with alkali absorption liquid.

8. The C-14 activity analysis pretreatment device in high-activity tritium water according to claim 7, characterized in that: The first glass bubbler (4) and the second glass bubbler (5) are both provided with a gas inlet at the top, and the first glass bubbler (4) and the second glass bubbler (5) are both provided with a gas outlet at the upper side; the gas outlet of the oxidation reactor (3) is connected to the gas inlet of the first glass bubbler (4) through a connecting hose (9), the gas outlet of the first glass bubbler (4) is connected to the gas inlet of the second glass bubbler (5) through a silicone tube (10), and the gas outlet of the second glass bubbler (5) is connected to the pipeline of the glass absorption bottle (6).

9. The C-14 activity analysis pretreatment device in high-activity tritium water according to claim 8, characterized in that: A quick connector (15) is provided on the connecting hose (9) connecting the gas outlet of the oxidation reactor (3) and the gas inlet of the first glass bubbler (4).

10. The C-14 activity analysis pretreatment device in high-activity tritium water according to any one of claims 7 to 9, characterized in that: The acid absorption liquid of the first-stage acid absorption device and the second-stage acid absorption device is H2SO4; the alkali absorption liquid of the alkali absorption device is NaOH.

11. The C-14 activity analysis pretreatment device in high-activity tritium water according to claim 10, characterized in that: The C-14 activity analysis pretreatment device in high-activity tritium water also includes a waste liquid absorption device, and the waste liquid absorption device is connected to the alkali absorption device pipeline.

12. The C-14 activity analysis pretreatment device in high-activity tritium water according to claim 11, characterized in that: The waste liquid absorption device is a glass colorimetric tube (7) filled with water.

13. The C-14 activity analysis pretreatment device in high-activity tritium water according to claim 12, characterized in that: A gas inlet is arranged at the top of the glass absorption bottle (6), a gas outlet is arranged at the upper side of the glass absorption bottle (6), the gas outlet of the second glass bubbler (5) is connected to the gas inlet pipeline of the glass absorption bottle (6), and the gas outlet of the glass absorption bottle (6) is connected to the pipeline of the glass colorimetric tube (7).

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