JPS60178397A - Method of treating radioactive waste liquor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a method for treating radioactive waste liquid generated in facilities handling radioactive materials such as boiling water nuclear power plants.
In particular, the present invention relates to a method for treating radioactive waste liquid, which involves drying radioactive waste liquid containing precipitable substances such as Glauber's salt.

[Technical background of the invention and its problems] In general, in facilities that handle radioactive materials such as nuclear power plants, large amounts of ion exchange resins are used in radioactive waste liquid treatment systems and other areas, and these ion exchange resins are periodically It is necessary to regenerate by cleaning with sulfuric acid and hydroxide.

The @acid and sodium hydroxide used to regenerate Eel resin were mixed into a waste liquid containing mirabilite, and this waste liquid contained ion-exchanged ionic radioactive substances and adhering to the resin surface. The cladding contains radioactive metal oxides, etc.

After that, such a turbulent waste liquid is concentrated in an evaporative concentrator and then sent to a dryer, for example, a vertical thin film dryer, where it is dried and coated on the inner wall of the dryer with mirabilite as the main component. This solidified material is mechanically scraped and pulverized to a particle size of 1 to 50 μm, and then sent to a Plasnac assimilation device or the like for assimilation treatment.

However, in this method, the solidified material deposited on the inner wall of the dryer is extremely hard because it contains Fe (ON>3, Ca, Si, etc., which are the main components of the cladding, in addition to Glauber's salt). Some of it remains deposited on the wall, putting an excessive load on the dryer.

Therefore, after a certain amount of waste liquid treatment, dryers are usually washed with warm water to remove any remaining precipitates, and then the waste liquid is treated again. It is taken.

The impossibility of continuous operation of waste liquid treatment in this way means a decrease in waste liquid treatment efficiency, and also leads to an increase in a large amount of radioactive cleaning waste liquid accompanying cleaning.

However, this washing waste liquid is sent back to the waste liquid treatment system as secondary waste.

Moreover, with the conventional hot water washing method, it is not possible to completely remove the precipitated solids on the surface of the dryer 57, and the precipitated solids that remain after washing are further hardened, and the precipitated solids are removed in the next waste liquid treatment process. This will increase the survival rate. As a countermeasure to this problem, the "wi4 water washing method" has been considered, but it has drawbacks such as a complicated dryer structure and an increase in washing waste liquid.

-jj, such a dryer is suitable for drying dryers containing mirabilite mentioned above.
In addition to bamboo waste liquid, the drying process can also be carried out for waste liquid including waste resin and waste sludge. In the case of drying, the waste resin etc. is simply dried while violently colliding with the wall of the dryer, and no solidified material is deposited on the surface.

1. Purpose of Brahma] This defense is made in response to these conventional circumstances! ζ Mono C1 Save time by omitting the cleaning process after waste liquid treatment! The present invention provides a method for treating radioactive waste liquid that enables continuous waste liquid treatment between 1 and 2 and reduces the generation of cleaning waste liquid.

"Overview of light use" In other words, the method for treating radioactive waste liquid of the present invention is to
In drying the radioactive waste liquid, a first step is to supply the fi-resistant waste liquid containing a precipitable substance to the dryer and dry and cover it, and to supply a liquid containing a non-precipitable particulate substance and dry it. It is characterized by repeating the second 1' culm alternately.

[Embodiments of the Invention] The details of the present invention will be described below with reference to the drawings and embodiments.

FIG. 1 shows a drying apparatus equipped with a vertical thin film dryer used in carrying out the method of the present invention.

In FIG. 1, reference numeral 1 denotes a container body 2 and a pulley 3 that is inserted into the container body 2 and whose upper end is above the container body 2.
a shaft 5 having a movable wing 4 fixed to the container body 2;
This figure shows a vertical thin film dryer comprising a heating duct 6 that surrounds a heating duct 6 and in which high-temperature steam is circulated.

A powder transport device, for example, a powder feeder 7, for transporting the radioactive powder dried to the vertical thin film dryer 1 is disposed on the bottom exit side of the vertical thin film dryer 1. The powder feeder 7 has an assimilation device measuring lower 1 and an outlet lower 2 opening to a cleaning waste liquid tank 8 that stores cleaning waste liquid.

In addition, on one side of the vertical thin film dryer 1, from a concentrated waste liquid storage tank 9 in which concentrated radioactive waste liquid containing mirabilite is stored and a waste resin or waste sludge storage tank 10,
The concentrated waste liquid J3 and waste resin or waste sludge transferred by the concentrated waste liquid transfer pump P1 and waste resin or waste sludge transfer pump P2 and stored in the waste liquid supply tank 11 are transferred to the vertical thin film dryer I11 by one waste liquid supply pump 3. A pipe 12 that supplies the container body 2 is connected.

Further, above the side wall of the vertical thin film dryer 1, a container body 2 is provided.
A pipe 14 is connected to the condenser 13 for guiding the components evaporated in the condenser 13 to the condenser 13. This evaporated component is condensed by the condenser 13,
It is transferred again to the high-conductivity melon waste liquid system as radioactive waste liquid. Further, this vertical thin film dryer 1 is provided with a cleaning device 16 that discharges hot water for cleaning from a cleaning nozzle 15 into the container body 2.

In the present invention, using the drying treatment apparatus configured as shown in FIG. be done.

That is, 11i! The waste d adheres to the inner wall of the container body 2 under the centrifugal force of the movable */I rotated by the motor M, forming a thin film. This film flows down while being dried by the heat from the heating duct 6, and precipitates and covers the lower wall surface of the container body 2 as a solidified substance mainly composed of mirabilite.

Most of this solidified material is scraped off by the movable blade 4 and falls into powder with a particle size of 1 to 50 .mu.mk, and is sent to the assimilation device by the powder feeder 7. Also, part of it, σ
In other words, the solidified material existing in the gap between the movable blades 4 and the wall surface of the container body 2 remains as is.

Here, in the conventional method, cleaning is performed to remove the solidified material remaining on the wall surface, but in the method of the present invention, the vertical thin film dryer 111 is filled with filaments containing waste resin or waste sludge.
The radioactive waste liquid is supplied and a drying process is performed.

In other words, the centrifugal force of the movable blades 4 rotating at high speed violently collides with the wall surface of the container body 2, and the movable blades 4 and the container body 2 collide violently.
It falls between them, being crushed and dried into a powder. During this time, the solidified material remaining on the wall and containing 1 = mirabilite as a main component is scraped off.

In addition, the waste liquid containing these waste resins or waste sludge contains almost no mirabilite precipitable substances, so
New precipitation of solidified material on the wall surface of the container body 2G;L
/,,:stomach. Therefore, the wear of the movable blade 4 and the motor load of 1+R do not occur, as occurs with radioactive waste liquid containing salt.

Figure 2 shows the change in the Fi power consumed by the motor M in response to a 1.1 change in the concentration of the precipitable substance mainly composed of mirabilite precipitated on the wall of the vertical thin film dryer 'a1. It can be seen that as the precipitable substance concentration increases to 5 wt% or more, the power consumption of the vessel increases rapidly, and the load on the P-ta N4 increases.

According to the present invention, the waste liquid containing waste resin and /' or waste sludge may contain precipitable substances such as calcium hydroxide. It is desirable that it is less than %.

The measured values in Figure 2 are that the heat transfer area of the vertical thin film dryer is 0.5 + n', and the power consumption value of the motor M is t9
．． This is the value when the machine operation reaches steady state.

Further, in the present invention, the preferred m degree of non-precipitable particulate matter such as waste resin or waste sludge in the waste liquid is 20 W 1% or less.

In this way, in Example 1, the remaining solidified matter that was previously dissolved by the dry water cleaning method, etc., is removed at the same time as the drying process by supplying waste liquid containing waste resin or waste sludge. Therefore, the next treatment of waste liquid containing Glauber's salt can be carried out without adding washed culms.

FIG. 3 shows a second waste solution containing Glauber's salt that is similar to that obtained when the waste solution containing the waste resin or waste sludge of the present invention is supplied after the first waste solution containing Glauber's salt is subjected to conventional drought cleaning. This is a comparison of the time it takes for the motor power consumption to reach a steady state when the mirabilite temperature is 11 degrees during treatment, and it shows that the waste liquid treatment containing waste resin or waste sludge of the present invention has the same effect as drought cleaning. It shows. In FIG. 3, the horizontal axis shows the concentration of mirabilite, and the vertical axis shows time, where . is the case of drought cleaning and Δ is the case of the example. In addition, in this experiment, a vertical type other film dryer was also used.
The heat transfer area of the machine is <0.5TI+2, which is the same as the experiment in Figure 2.
It is.

The above has described the method of the present invention in which continuous operation of the vertical thin film dryer is avoided. However, in the present invention, when the operation of the dryer is stopped, after treating the radioactive waste liquid containing mirabilite, containing waste resin or waste sludge
After supplying the waste liquid, the cleaning nozzle 1 of the cleaning unit 16
Hot water is discharged from 5 to clean the inside of the C vertical thin film dryer 1, and then the inside of the C vertical thin film dryer 1 is dried and then stopped. In this way, by supplying waste liquid containing waste resin or waste sludge that does not contain precipitable substances and operating the dryer 1 before the cleaning process, the remaining precipitated solidified material is almost completely removed, so that the cleaning process is easy. The drought that is going on is a little ff1T-good.

In the examples from J3 to t, an example was shown in which a vertical m-membrane dryer was used as the dryer. Any dryer capable of mechanically scraping and pulverizing the solidified material can be applied, such as groove type and cylindrical stirring dryers, drum and cylindrical dryers, etc.

In addition, as the liquid containing non-precipitating particulate matter of the present invention, the radioactive waste liquid containing the waste resin or waste sludge shown in the above examples is suitable as it also serves as waste 'a treatment, but other liquids such as glass-like particles, It is also possible to use a liquid containing ceramic powder or the like.

[Effect of the invention 1 As explained above, according to the present invention, there is no need for cleaning that was performed every time waste liquid treatment is performed, and there is no increase in the load on the dryer due to insufficient cleaning as in the past. This makes it possible to carry out continuous waste liquid treatment over a long period of time, and to significantly reduce the generation rate of secondary waste such as cleaning waste liquid.

[Brief explanation of the drawing]

Figure 1 is a piping system diagram of the drying equipment to which the method of the present invention is applied, Figure 2 is a graph showing changes in the load on the dryer with respect to the concentration of precipitable substances in the waste liquid, and Figure 3 is the cleaning method according to the present invention. It is a graph showing the effect (precipitation solidification removal effect). 1... Vertical thin film dryer 2...
......Container body 3...Pulley 4...Movable wing 5j...・・Shift 6・・・・・
...... Heating duct 7 ...... Powder feeder 9 ...... Concentrated waste liquid storage tank 10 ...... ...Waste resin or waste sludge storage tank + 1 ...Waste liquid supply tank '12
．． 14... Piping 13... Condenser 1) +... Concentrated waste liquid transfer pump 1
〕2・・・・・・・・・Waste resin or waste sludge transfer pump】〕３・・・・・・・・・・・・Waste liquid supply pump M...
・・・・・・・・・・・・・Motor's Patent Attorney Su
Yamasa - Figure 1 Figure 2 〇 Gosoku Storm Page 1 continued 0 Inventor Kiyoji Sakamoto 1-6 Tokyo Office, 1 Uchisaiwai-cho, Chiyoda-ku, Tokyo Tokyo Shibaura Electric Co., Ltd.

Claims (3)

[Claims] (1) When drying the tIi Swordsman 1 waste liquid using a dryer, the first step of supplying the radioactive waste liquid containing precipitable substances to the dryer and drying it, removes the liquid containing non-precipitable particulate substances. A method for treating radioactive waste liquid characterized by alternately repeating two steps of supplying and drying the same. (2) The method for treating radioactive waste liquid according to claim 1, characterized in that (4) when the dryer operation is temporarily stopped, a cleaning treatment is performed after the second culm. (3) Liquid containing non-precipitable particulate matter is waste resin j3 and/or
The method for treating a radioactive waste liquid according to claim 1 or 2, which is a radioactive Ti waste liquid containing waste sludge.