JPS6025499A - Glass solidifying treating method of radioactive waste - 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] The present invention relates to a method for assimilating radioactive waste.

In recent years, a method has been developed that promotes the volume reduction treatment of radioactive waste (by closing the radioactive waste) and injecting the radioactive waste into the solidified material. This method uses concentrated waste liquid (approximately 20% Na2) generated from nuclear power plants (BWR).
By mixing the dry solid content (including SO4) with auxiliary agents such as clay containing 5i02 as the main component and melting this at a high temperature of approximately 1.200°C, the following lath-forming reaction occurs. It is then cooled and solidified.

Na2SO4+ nS 102-Na20 ・nS i
02+sO2↑+1021 Here, during the above vitrification reaction b
Na2O.r+s+02 is sorter silica j3 lath used for windows j3 lath and the like.

However, according to the method of mixing and melting only such a dry solid content and an auxiliary agent such as clay containing 5i02 as a main component, the temperature at which the 13 lazing reaction occurs is high, the reaction rate is slow, and there are problems during melting. Nose generated inside (SO□, CO
□) was not removed sufficiently.

The present invention aims to solve such problems by melting at high temperature a mixture of dry solid radioactive waste generated from nuclear power plants and an auxiliary agent mainly composed of 5i02 such as clay. By providing a method for solidifying radioactive waste, the method includes adding graphite or coal in the dry solid form (at least 5% by weight) to the mixture during solidification. This is to achieve the purpose, and with this first step, the temperature at which the halasing reaction occurs can be kept low, the reaction rate can be accelerated, and the nozzles generated inside during melting can be sufficiently removed. It's possible.

The method of the present invention will be explained in detail below based on the drawings showing one embodiment thereof.

As shown in FIG. 1, first, radioactive concentrated waste liquid (2) generated from a nuclear power plant (1) is dried and solidified (3).

This gives dry salt (dry solids) (4).

On the other hand, clay (5) containing 5i02 as a main component is prepared.

Next, these dry salts (4) and clay (5) are mixed (0).

At this time, if the amount of dry salt (4) is too small, the mixture will become soluble.
+cll L, but sufficient j3 lath formation reaction cannot occur, and even if the amount of dry salt (4) is too large, unreacted dry salt (4) “v′Il′!, :j (4) The remaining portion is inappropriate. Therefore, the appropriate proportion of dry salt (4) is 30 to 50% by weight of the entire mixture.

Next, graphite (or coal) (7) is added to this mixture in an amount of 5% by weight or more based on the dry salt weight of the mixture (11), and thoroughly mixed (6).

Then, the mixture prepared in this way is heated and poured into a 1.8 t (SL) container using a heating method such as 90 wave heating, high frequency induction heating, electric resistance heating, etc., and is solidified in a j5 lath (9). As a result, a 3 lath solidified body is formed. Then, it is disposed of on land or in the ocean as appropriate.

Next, the effects of such a method will be explained based on experimental results.

First, as experiment 1, a sample of dry salt (mixture of 4% MO and 60% clay (6)) was heated at 1.050°C to 1.800°C.
After heating for 1 hour at a temperature of °C (8), the dried salt (4)
and the bassing reaction rate of clay. Figure 2 shows the results. As is clear from the figure, the glass formation reaction rate is quite low at this temperature. Here, the j5 lathization reaction rate is 1'i'l! I did N
The weight ratio of the first mixed dry salt to the weight of a2SO4.

Next, as experiment 2, add 5 to 50 liters of salt to the sample mixed in experiment 1 based on the weight of dry salt in it. V (% graphite (7)
was added and heated at 1.050° C. for 1 hour (8), and the glass formation reaction rate between the dry salt (4) and the clay was examined. In addition, FIG. 3 shows Ii 4 and 14. It is clear from the figure that by adding 5% by weight or more of graphite (7), the fucolasization reaction rate exceeds 80%, and the resulting solidified material is also of a uniform quality. became. It should be noted that similar experimental results were obtained for different mixtures of dry salt (4) and viscous IJb compounds, and also for different temperatures.

As described above, according to the method of the present invention, the Jj vitrification reaction occurs.
i14 degrees can be kept low, and the reaction rate can be adjusted to reduce the internal temperature generated during melting; j
It is also possible to sufficiently remove the heat.

[Brief explanation of the drawing]

Figure 1ni is for explaining the method of the invention. Figure 1 shows the flow 1>:I, Figures 2 and 3 show the experimental results, and Figure 2 shows the relationship between temperature and lathization reaction rate. Figure 3 is a diagram showing the relationship between ship weight (total) and vitrification reaction 5Y<1), and Figure 11. (1)...Ji7 power plant, (2)...radioactive concentrated waste liquid, (3)...1 tbsp dry solid, (4)...dry salt,
(5)...Clay, (6)...Mixing, (c graphite, chemical) - heating and melting, (9)...F'i: +, 717. II
k Fig. 1, [:; Nii, W, lead amount (%2

Claims (1)

[Claims] ＋, Jl:j子力源V(＜Drying of radioactive waste generated from places, etc.) Ill,! 1. A method for gas solidification of radioactive waste, comprising adding to the mixture graphite or coal mainly composed of 5i02, such as clay.