RU113412U1 - DEVICE FOR REMOTE DOSING OF MICROALIQUOTES OF HIGHLY ACTIVE RADIONUCLIDE SOLUTIONS - Google Patents

Abstract

A device for remote dosing of microaliquots of radionuclide solutions, including a bellows, a vacuum hose, a calibrated capillary, an indicator and a replaceable tip, characterized in that it additionally contains a capillary tube connecting the replaceable tip with a calibrated capillary, and the bellows, vacuum hose and calibrated capillary are filled with an indicator and placed in the operator room, and the replaceable tip is located in a protective box.

Description

The utility model relates to the field of processing of irradiated materials and can be used for analytical control of radionuclide production.

Widely used for dispensing small volumes of plunger type pipettes, manufactured abroad. But they are not used for remote dosing of solutions, because it is difficult to control manipulators with such pipettes.

Pipettes with expansion according to GOST 1770-64 are used for dispensing large volumes of solutions (more than 10 ml). OST 95 10236-86 recommends the use of pipettes with divisions with a capacity of 0.1-10 cm ³ not less than the 2nd accuracy class according to GOST 20292-74, providing measurement of the sampled solution volume with an error within ± 2% when dosing at least half the pipette volume.

For remote dosing of solutions, in practice, pipettes with a capacity of 1 and 2 ml are mainly used, which allow you to select aliquots of 0.5-2 ml with the required accuracy. When dosing volumes of less than 0.5 ml, the measurement error of the dosed volume increases dramatically.

For remote dosing of small volumes of solutions, micropipettes (OST 95 10236-86) with a capacity of 0.1 ml are used.

The device consists of a bellows located in the control room, a micropipette with a capacity of 0.1 ml, serviced remotely and a connecting vacuum hose.

The main disadvantage of this device is the placement of the micropipette in the protective equipment, which creates difficulties when visually observing the calibration markings of the micropipette and fixing the volume of the selected colorless solution.

In addition, due to the small diameter of the micropipette capillary, it is difficult to ensure its cleanliness during washing, decontamination, degreasing for reuse. Contamination of the pipette, especially with organic substances (extractant, oil, fat, etc.), leads to the retention of the analyzed solution inside the capillary, sorption of radionuclides by organic substances is possible.

The closest in essence to the proposed is a device for remote dosing of small volumes of solutions (Kalygin A.V., Anokhin Yu.P. Device for remote dosing of microaliquots of highly active solutions of radionuclides, Patent No. 42346, Bull. No. 33, 2004) representing U - a tube consisting of two capillaries (or pipettes with a capacity of 0.1 ml) interconnected by a silicone hose and filled to half the volume with a tinted solution or mercury (indicator). A replaceable tip (for example, from Polish ARB pipettes) is connected to one capillary through a stainless steel cone for the selection of solutions, the other capillary is connected via a vacuum hose to a bellows located in the control room. The device is pre-calibrated before use. The error in determining the volume during calibration on a Sartorius scale is about ± 1%.

The disadvantages of this device is that the entire device is placed in a protective box (except for the bellows). It is very difficult to identify and eliminate malfunctions in the U - tube, for example, to notice and remove droplets of mercury on the walls of glass capillaries in time, which can lead to an additional error in measuring the dosed volume up to a “rough blunder”.

The presence of impurities in the indicator gradually pollutes the U - tube, but it is almost impossible to replace it with a new one in remote conditions. Therefore, it is necessary to change the entire device (except the bellows) as a whole.

In addition, observing through viewing systems the movement in the indicator capillary (meniscus) is quite laborious, which can also lead to a “rough miss” during measurements.

The above disadvantages are eliminated by the fact that the device for remote dosing of microaliquots of highly active solutions of radionuclides, including a bellows, a vacuum hose, a calibrated capillary, an indicator and a replaceable tip, additionally contains a capillary tube with an inner diameter of 0.2-0.4 mm connecting the replaceable tip with a calibrated capillary, moreover, the bellows, the vacuum hose and the calibrated capillary are filled with an indicator and placed in the operator’s room, and the replaceable tip is placed in a protective box.

The “parasitic" volume of air inside the capillary tube, with a length of about 3 meters and an inner diameter of not more than 0.4 mm, is less than 0.4 cm ³ and does not increase the measurement error of the dosed volume. The device is pre-calibrated before use.

The attached figure shows a device for remote dosing of microaliquots of highly active solutions of radionuclides where:

1. - bellows;

2. - compensator-vacuum hose;

3. - calibrated capillary;

4. - capillary tube;

5. - interchangeable tip.

Mount the device by connecting a bellows, a compensator and a capillary in the operator's room, then connect a capillary tube to the capillary. The length and configuration of the tube is such that the interchangeable tip is located in the area of the viewing window in the protective box. The compensator is made of a vacuum hose.

After preliminary calibration of the inventive device, a comparison was made of the results of determining the activity of the curium-244 radionuclide with remote dilution of solutions of the proposed device and the prototype device. The resulting error in the determination of curium activity is ± 4-5%. The results are shown in the table.

Table No. Test results for remote dilution of solutions
Δ = ± (4-5)% Discrepancy of results% Proposed device Prototype device one 2.26 ∙ 10 ¹⁰ Bq / ml 2.25 10 ¹⁰ Bq / ml +0.4 2 2.33 ∙ 10 ¹⁰ Bq / ml 2.27-10 ¹⁰ Bq / ml +2.6 3 5.2 Ci / L 5.3 Ci / L -1.9 four 17.5 Ci / L 18.1 CI / L -3.3 5 22.5 Ci / L 21.7 Ci / L +3.7 6 88 ci / l 91 CI / L -3.4 7 5.62 ∙ 10 ⁹ Bq / ml 5.62 ∙ 10 ⁹ Bq / ml 0 8 0.83 Ci / L 0.81 Ci / L +2.5

The results of determining the activity of a radionuclide during dilution of solutions with the proposed device and the device of the prototype do not significantly differ from each other and are within the error of radiometric measurements.

Using the inventive device provides guaranteed visual control of the volume of the selected solution, avoids gross blunders, simplifies the replacement of the graduated capillary and reduces the radiation dose to the lens of the eye.

Claims (1)

A device for remote dosing of microaliquots of radionuclide solutions, including a bellows, a vacuum hose, a calibrated capillary, an indicator and a replaceable tip, characterized in that it further comprises a capillary tube connecting the replaceable tip to a calibrated capillary, and the bellows, vacuum hose and a calibrated capillary are filled with an indicator and placed in the operator’s room, and the replaceable tip is placed in a protective box.