JPS62282264A - Apparatus for automatic titration of plutonium - Google Patents

Abstract

PURPOSE:To enhance working efficiency, by automatically performing the titration operation of plutonium by intermittently and successively transferring the row of containers receiving a plutonium specimen solution. CONSTITUTION:A large number of containers 2 are arranged on a transfer device 1 and individually transferred to the direction shown by an arrow (a) intermittently and successively at every one step. A first stop position A and a second stop position B are provided on the way of the transfer passage and each container 2 is detected by a position detector 3 to stop at each position and a predetermined reagent is added to the container 2 or titration is performed during stop. A first valency controller 7 and a powder adding device 8 are arranged in the vicinity of the position A while a second valency controller 9 and a titration device 10 are arranged in the vicinity of the position B. These devices 1, 7-10 and a washing device 20 are arranged in a glove box 30 while a buret device 31 and a potential difference measuring device 32 etc. are arranged outside the box 30. The operation of each device and the analysis of measuring result are entirely performed by a controller 34 in synchronous relation to the intermittent transfer of the container row.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention (Field of Industrial Application) The present invention relates to an automatic titration device that can automatically perform seismic intensity analysis of a plutonium solution reagent.

<Conventional technology> In order to reuse the nuclear fuel used in a nuclear reactor, fission products are removed to produce plutonium (Pu) and uranium (U).
At spent nuclear fuel reprocessing plants and other facilities that handle radioactive materials in order to extract and separate plutonium, it is necessary to analyze the concentration of plutonium solution samples.

Potentiometric titration is widely used to analyze the concentration of plutonium solution samples, and generally, nitric acid and silver peroxide powder are added to the plutonium solution to adjust the valence to After decomposing the excess silver peroxide powder by adding a minic acid solution, an iron(II) standard solution was added to decompose the Pu
(IV), and a method is adopted in which excess iron (II) is titrated with a potassium dichromate standard solution.

<Problems to be solved by the invention> However, since plutonium exhibits extremely strong decay and is toxic, sufficient care must be taken when handling it.Therefore, the above titration operation must also be performed in a glove box, which reduces work efficiency. It was also bad.

In addition, since pretreatment for sample preparation, titration operations, and data processing were performed manually by an analytical operator, there was a drawback that the analytical results varied widely depending on the skill level of the operator.

Therefore, the present invention is capable of automatically performing the plutonium titration operation as described above, thereby improving work efficiency and eliminating variations in analysis results due to differences in the skill of operators. The purpose of this invention was to provide a titration device for

<Means and effects for solving the problems> The automatic plutonium titration device according to the present invention has a first stop position in the middle of the transfer path of the transfer device that sequentially transfers the rows of containers containing plutonium sample solutions intermittently. and a second stop position in this order, and a first valence adjusting device having a nitric acid addition nozzle and a sulfuric acid addition nozzle near the first stop position, and a powder for adding silver peroxide powder a predetermined number of times. An addition device is provided so that nitric acid, silver peroxide powder, and sulfamic acid can be added in this order into the container at the first stop position, and a sulfuric acid addition nozzle and iron (
II) A second atomic titration device having a solution addition nozzle and a titration device having a potassium dichromate standard solution addition nozzle and an electrode are provided to add sulfuric acid and iron(II) solution in a container in a second stop position. and the required amount of potassium dichromate standard solution for titration in this order, and a cleaning device is provided near the titration device for cleaning the used potassium dichromate standard solution addition nozzle and electrode. each of the devices is arranged in a glove box, and each of the reagent addition nozzles is connected to a buret device for each reagent provided outside the glove box, so that the reagent of the predetermined device is discharged from the corresponding nozzle; The electrodes of the titration device are connected to a potential difference measurement device installed outside the glove box, and the analysis of the measurement results and the operation of each device are performed by a controller installed outside the glove box in synchronization with the intermittent transfer of the container row. , 1fiX was created.

With this configuration, the titration operation inside the glove box can be controlled by remote control from outside the glove box, and the titration operation inside the glove box can also be automated reliably and quickly, making the work easier. This makes it possible to eliminate variations in analysis results between different researchers.

<Examples> The present invention will be described below with reference to drawings showing examples.

FIG. 1 is a schematic explanatory diagram of the entire apparatus of the present invention, in which a plurality of containers 2 are arranged on a transfer device 1, and each container in the container row is moved intermittently every step in the direction of arrow a. Transferred sequentially. In the middle of this transfer path, there are a first stop position A and a second stop position A.
Stop positions B are provided in this order along the transfer direction, and the containers transferred to these positions are detected by the position detector 3 and stopped at each position. During this stop period, a predetermined reagent is added, Alternatively, titration is performed. The transfer device 1 can be composed of a turntable 6 driven by a motor 4 and a chain 5, as shown in FIG.

A first valence adjustment device 7 and a powder addition device 8 are arranged near the first stop position A, while a second stop position B
A second valence adjustment device 9 and a titration device 10 are arranged near the. The first valence adjustment device 7 has an arm 11 that is pivoted as shown in FIG.
3 is installed, in the forward position of the arm 11 these nozzles 12.13 discharge nitric acid and sulfamic acid into the container 2 in the rest position Δ, and in the (transferred position of the arm 11) the nozzles 12.13 These reagents are taken out from the container 2 so as not to be discharged.

The second valence adjustment device 9 and the titration device 10 also have a first
Arms 14 and 15, which function similarly to the arm 11 of the atomic rO adjustment device, are each pivoted, and the tip of the arm 14 is equipped with an ffEi1m addition nozzle ``16'' and a ferro(II) solution addition nozzle ``17.'' A potassium dichromate standard solution addition nozzle 18 and a platinum composite electrode 19 are attached to the tip of the arm 15.

When the arm 15 of the titrator 10 is in the retractor, in other words the potassium dichromate addition nozzle 18 and the electrode 19 are retracted from their used position in the container 2 (phantom lines in FIG. 2). When in position (solid line in FIG. 2), these nozzles 18 and electrodes 19 are directly above the cleaning device 20. This cleaning device 20 has a row-shaped outer shape, and a cleaning water@steel pipe 21 is disposed at the inner periphery of the upper opening. ) first) will be contested.

The powder addition device 8 adds one tablet of silver peroxide powder tablets 22 compressed to a predetermined size into the container 2 located at the stop position Δ.

The above-mentioned transfer device 1, first valence adjustment device 7, powder addition device 8, second atom adjustment device 9, titration device 10 and cleaning device 20 are located inside the glove box 30 shown by the dotted line in FIG. On the other hand, outside the glove box are a burette device 31, a potential difference measuring device 32,
A manual operation panel, relay unit I-33, controller 34, computer 35, printer 36, etc. are installed.

The Huuret device 31 includes Seidan Buret 41, Sulfamic acid Buret 42, and Sulfuric acid puree 1 to 43.
, a dichromic acid solution burette 44 and a dichromic acid solution burette 45 are provided, each buret having a corresponding reagent addition nozzle 12.1.
3, 16.17°18 and tubes TI and T respectively
2, T3.

T4. T5, and a predetermined amount of reagent is discharged from the corresponding nozzle. The potentiometric measuring device 32 is connected to the electrode 19 of the titration device 10 by a line L, and receives a potentiometric titration signal from the electrode. The operation of each of the above-mentioned devices and the analysis of measurement results are all controlled by a controller 34 including a computer 35 via a manual operation panel and a relay unit 33 in synchronization with the intermittent transfer of container rows, and the operation of each device is confirmed. The signals and measurement results are printed by the printer 36 as necessary.

Next, the operation of the apparatus of the present invention will be explained with reference to analytical experimental examples.

Load the program into the computer for i-inhibition (blank measurement) of the iron(II) solution, input the titration conditions, atomic fi [Ii adjustment reagent addition amount, sample 1'; l number, and set the container 2 on the transfer device 1. and start the titration operation.

1) When the container on the transfer device is transferred to the stop position fi3, it is detected by the position detector 3 and stopped, and the second valence adjustment device 9
60 m of sulfuric acid (2N), Q, is added into the container from the nozzle 16.

2) Iron (II>
5 ml of solution (5!ft ammonium acid solution) is added and entrained by a magnetic stirrer.

3) Next, the tips of the nozzle 18 and electrode 19 of the titration device 10 are immersed in the solution in the container, and the potassium dichromate standard solution is dripped from the nozzle 18 to perform titration.

4) The end point of the potentiometric titration is detected by the electrode 19 and the potentiometer 32, and this data is sent to the computer 35 and printer 36'.

5) The nozzle 18 and electrode 19 are taken out from the container and cleaned by the cleaning device @20.

6) Perform the above series of operations for the number of samples (61), and the measurement data is sent to the computer 35 for each time to be stored and displayed on the printer 36.

Following the constant loss blank measurements of plutonium standard samples and analysis samples, measurements of standard samples are performed in order to manage analytical accuracy and accuracy of analytical values in daily analytical operations, and check the operating status of the titration device. This measurement data is subjected to Nu control to check changes in the average value and R control to check changes in variation using a computer, and if it is within the control limits, then the analysis sample for which the plutonium concentration should be determined is determined. Measure. The titration operation for both the standard sample and the analysis sample is as follows.

1) Take sample 2- with whole pipette 1~, and put it in a container (10
0 mg capacity beaker), and place this container on the transfer device 1.

2) When the container on the transfer device is transferred to the stop position A, it is detected by the position detector 3 and stopped, and the nozzle 12 of the first valence adjustment device 7 adds nitrification (1+2>5 mg into the container). , stirred by a magnetic stirrer.

3) Tablets 22 of silver peroxide powder, which are preset in the powder addition device 8, are added into the container.

As a result, Pu (IIl, IV, Vl) in the sample
) is valence-adjusted to Pu(Vl). After valence adjustment 5
Leave for a minute.

4) Sulfamine from the nozzle 13 of the first valence adjustment device 7! (10%) solution is added into the container.

This decomposes excess silver peroxide.

5) The container is roughly transferred by the transfer device 1 and reaches the stop position @
At B, it is detected again by the position detector and stopped, and sulfuric acid (2N>60IIlf
J is added into the container.

6) Iron(II) from the nozzle 17 of the second valence adjustment device 9
5 mF of solution (ammonium sulfate solution) is added and stirred with a magnetic stirrer. As a result, the valence is readjusted to Pu(IV).

7) Next, the nozzle 1B of the titration device 10 and the tip of the electrode 19 are immersed in the solution in the container, and a potassium dichromate standard solution is dripped from the nozzle 18 to perform titration.

8) The end point of the potentiometric titration is detected by the electrode 19 and the potentiometer 32, and this data is sent to the computer 35 and printer 36.

9) Nozzle 18 and Electrode] 9 is taken out from the container and cleaned by the cleaning device 20.

10) Perform the above series of operations for the number of samples (2 standard samples, 6 analytical samples), and the measurement data is sent each time to the computer 35 to be recorded and displayed on the printer 36.

Using the above measurement data, the concentration of plu-1 to nium in the analysis sample can be calculated by the computer 35 using the following formula.

Here, B is the consumption amount (IN) of potassium dichromate standard solution during iron (■) solution blank measurement, A is the consumption amount (mfJ) of potassium dichromate standard solution during sample measurement, and F is dichromate Pu equivalent group of acid potassium (m(]/mΩ), S represents the sample collection amount (1).

<Effects of the Invention> As can be seen from the above explanation, according to the present invention, the temperature analysis of a plutonium solution sample, which had conventionally been performed manually in a glove box in an inefficient manner, can be performed by rotating the sample container. Everything except loading and unloading onto and from a transfer device such as a table can now be done automatically and remotely from outside the glove box.

As a result, work efficiency can be greatly improved, and variations in analysis results due to differences in the level of comprehension of workers can be eliminated.

Also, regarding the equipment parts installed in the glove box, it will be easier to convert them into units 1~.
It also has the advantage that assembly, replacement, etc. of the device can be simplified and maintainability can be improved.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram showing an embodiment of the apparatus of the present invention, and FIG. 2 is a perspective view of a portion of the apparatus shown in FIG. 1 installed in a glove box. 1...-transfer device, 2...-container, 7...-first valence adjustment g'B, 8-powder addition device, 9...-second
valence adjustment installation, 10... titration device, 12... nitric acid addition nozzle, 13... sulfamine brewing addition nozzle,
16... Spore addition nozzle, 17... Iron ([) solution addition nozzle, 18... Potassium dichromate, standard solution addition nozzle, 19... Electrode, 20... Cleaning device, 30
... Glove box, 31... Buret device, 32... Potential difference measuring device, 34... Controller 1 to roller, 35... Computer, A... First stop position, B...・Second stopping position 2°

Claims (1)

[Claims] 1. A first stop position and a second stop position are provided in this order in the middle of the transfer path of a transfer device that sequentially transfers a row of containers containing plutonium sample solutions, and the first stop position and the second stop position are located near the first stop position. A first valence adjusting device having a nitric acid addition nozzle and a sulfamic acid addition nozzle and a powder addition device for adding a predetermined amount of silver peroxide powder are provided to add nitric acid and silver peroxide into a container in a first stop position. A second valence adjusting device that enables addition of the powder and sulfamic acid in this order, and has a sulfuric acid addition nozzle and an iron (II) solution addition nozzle near the second stop position, and potassium dichromate standard solution addition. a titration device having a nozzle and an electrode;
The sulfuric acid, iron(II) solution, and the titration required amount of the potassium dichromate standard solution are added in this order into the container at the stop position of the titrator, and the used potassium dichromate standard is placed near the titrator. A cleaning device for cleaning the solution addition nozzle and the electrode is provided, and each of the devices is arranged inside the glove box, and each of the reagent addition nozzles is connected to a buret device for each reagent provided outside the glove box. A predetermined amount of reagent is discharged from the corresponding nozzle, and the electrodes of the titration device are connected to a potential difference measuring device installed outside the glove box, and analysis of measurement results and operation of each of the devices are installed outside the glove box. An automatic titration device for plutonium, characterized in that the titration is performed in synchronization with intermittent transfer of container rows by a controller.