JPH0394122A - Method for measuring volume of air gap in radioactive solid waste container and method for fixing radioactive solid waste - Google Patents

Abstract

PURPOSE:To prevent the generation of the excess or shortage of the solidifying material to be injected into the air gaps in drum cans by measuring the pressures and temps. in the drum cans and an auxiliary container of a known volume, making prescribed computation, and thereby quantitatively measuring the air gap quantity before and after the injection of the solidifying material. CONSTITUTION:The drum can 4 contg. radioactive waste 3 is first placed on a weight meter 1 and the weight thereof is measured and is stored in an arithmetic circuit. The drum can 4 is then imposed on a base 2 in the position for injecting concrete mortar. A cap 12 is set on this drum. An air pipe 23, a thermometer 7, a vacuum gage 8, and a concrete mortar injecting pipe 13 are fixed thereto. The air pipe 23 is connected via a valve 20 to the auxiliary container 17 of the known volume. The pressure P1 and temp. T1 of the air gap 30 existing in the drum can 4 are measured and the pressure P2 and temp. T2 in the auxiliary container 17 having the pressure different from the pressure in the air gap 30 are measured. The air gap 30 and the auxiliary container 17 are then connected and thereafter, the pressure P3 and temp. T3 are measured. The volume of the air gap 30 is determined by computation in accordance with prescribed equation.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is a method for measuring the void volume of a radioactive solid waste container and a method for fixing radioactive solid waste.

(Prior art) So-called miscellaneous solid waste, which is combustible or non-combustible and has various shapes and properties, is disposed of in a landfill after being treated by incineration, compression, etc. according to each property. being reused. However, among these miscellaneous solid wastes, for example, nuclear power plants, nuclear research facilities, nuclear fuel handling facilities,
Radioactively contaminated waste generated from nuclear facilities such as nuclear fuel reprocessing plants and radioisotope handling facilities cannot be easily disposed of, so it is stored in-house at the waste source. In this case, in order to prevent the scattering of radioactivity from the waste and the spread of contamination, the waste is stored in a cylindrical container fitted with a drum can.

In addition, in order to save storage space as the amount of storage increases, some combustible waste is now being sterilized by incineration, and non-combustible waste in particular is being sterilized by compression. are beginning to be implemented or considered in some areas.

In these cases, a treatment method is being considered in which the radioactive waste is stored inside a container such as a drum and the void space is solidified with a solidifying material such as cement mortar.

(Problems to be Solved by the Invention) In recent years, burial disposal of these solidified bodies has been considered, but the amount of voids in the solidified bodies has become a problem.

In other words, if there are voids inside the container, the structural strength will decrease,
There is a risk of deformation when stacking containers. Furthermore, when water enters the voids during land disposal, harmful radioactive materials are likely to be eluted from these waterways.

In order to reduce the void volume in containers such as drums, methods of using highly fluid solidifying agents, injecting solidifying agents while applying vibrations, and vacuum injection are being considered.

However, since the amount of voids in the container is unknown when the solidifying material is injected, the necessary amount of solidifying material to be injected is also unknown, and the amount of concrete mortar etc. mixed in the mixer is often over or under. , leaving very large voids or wasting the mixed concrete mortar.

In addition, it is possible to know the weight of radioactive waste, the amount of solidification material injected, and the total volume of the container, but radioactive miscellaneous solid waste includes various miscellaneous materials such as metals, heat insulating materials, concrete, plastics, and flammable materials. Because it contains things with a shape of
The capacity is unknown, and the ease with which the solidifying material is injected also differs, making it impossible to quantitatively measure the voids in the final solidified material, making quality control impossible.

The object of the present invention is to develop a radioactive material that can quantitatively measure the amount of voids in the container before and after the injection of the solidifying material, and that can prevent excess or deficiency of the solidifying material injected into the voids. An object of the present invention is to provide a method for measuring the void volume of a solid waste container and a method for fixing radioactive solid waste.

(Means for Solving the Problems) The present invention measures the pressure P and temperature T of voids existing in a container containing radioactive solid waste, and measures the pressure P2 that is different from the pressure P1 of the voids. In addition, the pressure P2 and temperature T2 of the auxiliary container internal space whose volume v2 is known are measured, and then the pressure P3 and temperature T3 after the gap and the auxiliary container space are communicated are measured, and the following formula is obtained. According to the volume of the void V. A method for measuring the void volume of radioactive solid waste containers.

Further, the present invention provides a method for fixing the radioactive solid waste by injecting a solidifying material into the void existing in the container containing the radioactive solid waste. The present invention relates to a method for fixing radioactive solid waste, in which the injection volume of the solidification material is set according to the void volume v1 measured by the measurement method.

Furthermore, the present invention measures the void volume V, by the above-described method for measuring the void volume of a radioactive solid waste container, then measures the weight M of the solidification material injected into the void, and The present invention relates to a method for measuring the void volume of a radioactive solid waste container, which measures the volume of voids existing in the container after it has been fixed in the container.

5 6 V=V, -M/w (W indicates the specific gravity of the solidification material) (Example) The second construction drawing is a schematic diagram showing a fixing device for fixing radioactive solid waste in a container according to an example. It is a diagram.

First, a drum 4 containing radioactive solid waste 3 is placed on a weighing scale 1, the weight is measured, and this weight is stored in an arithmetic circuit.

Next, the drum 4 is placed on the stand 2 at a position where concrete mortar as a solidifying material is poured, and the lid 12 is set. An air vibrator 23, a thermometer 7, a vacuum gauge 8, and a concrete mortar injection pipe 13 are fixed to this lid 12,
The air pipe 23 is connected to the auxiliary vessel 7 via the valve 20. Using this auxiliary container 17, the capacity of the void 30 in the drum 4 is measured.

Specifically, the valve 18 is opened and the pressure inside the auxiliary container 17 is reduced using the pump 19 (on the contrary, the inside of the auxiliary container 17 may be pressurized above atmospheric pressure using a compressor).
The appropriate difference between P+ and P2 is 100 to 700 mmllg. Then, with the valve 18 closed and the valve 20 kept closed, using the thermometer 7 and vacuum gauge 8 attached to the lid 12 and the auxiliary container 17, respectively, as shown briefly in FIG. The pressure P2 and temperature T2 in the auxiliary container 17, the pressure p+ (for example, atmospheric pressure) in the drum 4, and the temperature T1 are measured. The volume v2 inside the auxiliary container l7 is known. These P
Each data of I+P2, TI, 'rz, and v2 is input to the arithmetic circuit.

Next, the valve 20 is opened to mix the air in the auxiliary container 17 and the air in the gap in the drum 4 to equalize their temperatures. Then, the system pressure P3 and temperature T3 are measured. This P3
, T3 data is also input manually to the arithmetic circuit.

According to these measured values, the air gap 3 in the drum can 4 is finally
0 capacity can be measured indirectly. That is, in the state where the valve 20 is closed, the lower part is in the precept position.

PH Vl-nl R T+ (n+ is the number of moles of air in the void 30) Pz V2=n2 R T2 (nz is the number of moles of air in the auxiliary container 17) Also, the valve 20
In the open state, the following formula stands out.

P3(Vl +VZ) = (r+++nz)R T3
From this, the capacity V of the air gap 30 can be determined.

Next, the capacity of the concrete mortar to be injected into the drum 4 is set based on the above measured value of the capacity V+, and the concrete mortar is injected into the void 30 based on this set value.

Specifically, first, the ratios of sand, cement, water, and admixtures that make up the concrete mortar are determined in advance. Then, based on the measured value of the volume V of the void 30, the injection volume of concrete mortar is set to a certain value (for example, 100 to 1
05%). Based on these set values, the required amounts of sand, cement, water, and admixtures, which are the raw materials for concrete mortar, are calculated, and only the required amounts are added to cement hopper 8, sand hopper 9, water hopper 10, and admixtures. Cement 1., sand, water, and admixture are respectively injected into the mortar kneader 5 from the hopper 11. Next, these raw materials are kneaded by a mortar mixer 5 and sent to a mortar transfer pump 6, and the required amount of mortar is sent to the mortar transfer pump 6 by a calculation circuit to control the amount of mortar discharged, and then transferred to a mortar hopper 7. Mortar 15 is then injected into the cavity 30 through the valve 12. Generally, all of the mortar is not discharged from the mortar kneading device, and some mortar remains in the device, so for the first batch only, the remaining amount of mortar is added to the calculated value of the amount of mortar injected. It is preferable to knead and produce extra mortar.

When pouring mortar, do so while monitoring with a mortar level meter. In order to inject the mortar into the voids without leaking and to reduce the amount of voids after injection, it is preferable to perform vibration injection and vacuum injection.

Depending on the shape of the void 30, there may be cases where the entire amount of mortar does not fit into the void, but in this case, the mortar is temporarily stored in the mortar hopper 6, and this stored amount is input to the calculation circuit.
For the next batch, this stored amount may be added to calculate the required amount of mortar, and the stored mol 9-10 tal may be reused. In addition, if it is inconvenient for quality control, the valve 2t is opened, the valve 22 is closed, and the discharge pipe 14 is closed.
It may also be discharged into the cleaning system.

Next, when the pouring of the mortar 15 is completed, the weighing scale 31
The drum 4 is transferred upward and its weight is measured.

Note that the weight of the drum after the mortar has been injected may be measured again using the weighing scale 1 that measured the weight of the drum before the mortar was injected. The weight of the drum after pouring mortar is input into an arithmetic circuit, and the mortar injection amount M is calculated from the difference from the weight of the drum before pouring mortar.

Further, a mortar sample is taken from the mortar sampling valve 6, and the specific gravity W of the mortar is measured and input to the calculation circuit. Note that since the proportions of water, cement, sand, and admixtures that make up the mortar are predetermined, the specific gravity of the mortar may be separately measured in advance and manually entered into the arithmetic circuit.

From this, since the mortar injection capacity is M/w, the void volume ■ of the solidified concrete mortar can finally be measured based on the following formula.

V-vl M/w According to this embodiment, the void volume in the drum before pouring mortar can be measured, and the amount of mortar required for solidification is set to an appropriate amount in advance based on this measured value. be able to. Therefore, it is possible to prevent the amount of mortar from being wasted due to too much mortar, or the amount of mortar being insufficient resulting in a large number of voids and a decrease in the strength of the solidified material. The generation of secondary mortar waste can be suppressed.

In addition, since the amount of voids inside the drum can be measured after the solidification material is injected, it is possible to control the quality, and it is possible to remove materials that are low in strength and are not suitable for land burial, or to adjust the strength by re-injecting mortar. can do.

Radioactive solid waste includes radioactive metals, heat insulating materials, vinyl chloride, concrete, etc., as well as drums containing these radioactive solid wastes and those that have been compressed and sterilized.

Alternatively, radioactive waste can be solidified with cement.
1] 2 The solidified material may be housed in a container, and this embodiment may be applied to this overback.

As a solidifying agent, in addition to concrete mortar, aggregates such as gravel may be added, and other admixtures or admixtures, such as AE agents, water reducing agents, expansion admixtures, accelerators, retarders, borazone, etc. may be included.

In addition to cement, coal, gypsum, asphalt, etc. may be used as a binder when kneading and producing a concrete mixture.

(Effect of the invention) According to the method for measuring the void volume of a radioactive solid waste container according to the present invention, an auxiliary container is used and the volume of the void existing in the container containing radioactive solid waste is v1
Since it is possible to measure the void volume vI, the amount of solidifying material to be injected can be set according to the measured value of the void volume vI. It is possible to prevent the generation of secondary waste, and also to prevent the strength of the solidified material from decreasing due to an insufficient amount of solidifying material resulting in a large number of voids, and to prevent radioactive waste from leaking through the voids.

Further, the void volume v1 is measured by the above method, and then the weight M of the solidifying material injected into the void is measured, and V=V. -M/
Since the volume of the voids existing in the container after fixing the radioactive solid waste is measured based on the relationship w, it is possible to measure the amount of voids inside the container after the solidification material is injected, which makes quality control possible. It is extremely useful industrially, and it is also possible to remove materials that have many voids and have low strength and are unsuitable for land burial, or to readjust the strength of the solidified material by reinjecting the solidifying material.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing a radioactive solid waste processing apparatus according to an embodiment of the present invention, and FIG. 2 is a schematic conceptual diagram showing the relationship between a drum and an auxiliary container. 1.31...Weight scale 3...Radioactive solid waste 13 1 4-4...Drum 5...Concrete monorethane kneading machine 12...
Lid 15... Concrete mortar 17... Auxiliary container 18, 20, 2L 22... Valve 19...
・Reducing pump P1...Pressure of the gap inside the drum before opening the valve v1...
Volume of the void inside the drum T1...Temperature of the void inside the drum before opening the valve P2...
Pressure inside the auxiliary container before opening the valve v2...Volume of the auxiliary container T2...Temperature inside the auxiliary container before opening the valve P3...Pressure after opening the valve T3...Temperature after opening the valve I 5

Claims (1)

[Claims] 1. Measure the pressure P_1 and temperature T_1 of a void existing in a container containing radioactive solid waste, and determine whether the void has a pressure P_2 different from the pressure P_1 and has a known volume V_2. Measure the pressure P_2 and temperature T_2 in the internal space of a certain auxiliary container, then measure the pressure P_3 and temperature T_3 after communicating the void and the auxiliary container space, and calculate the volume V_1 of the void according to the following formula. A method for measuring the void volume of a radioactive solid waste container. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ 2. When fixing the radioactive solid waste by injecting a solidifying material into the void existing in the container containing the radioactive solid waste, A method for fixing radioactive solid waste, comprising setting an injection volume of the solidification material according to a void volume V_1 measured by a method for measuring void volume of a radioactive solid waste container. 3. Measure the void volume V_1 by the method for measuring the void volume of a radioactive solid waste container according to claim 1, then measure the weight M of the solidification material injected into the void, and measure the radioactive waste. A method for measuring the void volume of a radioactive solid waste container, the method comprising: measuring the volume V of the void existing in the container after being fixed in the container according to the following formula. V=V_1-M/w (w indicates the specific gravity of the solidification material.)