JPS61287601A - Treating vessel for 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 [Field of Industrial Application] The present invention relates to a container for the treatment and disposal (hereinafter simply referred to as treatment) of waste, particularly radioactive waste and industrial waste, which is internally lined with dense concrete or mortar.

[Conventional technology and its problems]

In recent years, waste has been increasing, especially industrial waste such as various radioactive wastes discharged from nuclear facilities such as nuclear power plants and nuclear power plants, and hazardous heavy metal sludge discharged from chemical factories. I'm having trouble dealing with it.

Unlike heavy metals, each radioactive substance decays and decays with its own unique half-life, so there is a finite period of time during which it must be isolated from our environment. The waste products that have long lifetimes in current nuclear fission-based systems are mainly generated from nuclear fuel reprocessing plants. Its lifespan is 90 Sr, B 7 ca
If we focus on the β-r radiation performance like this, it will take several hundred years, and if we focus on the α radioactivity of transuranium elements with atomic numbers of 96 or higher, it will take several hundred thousand years. Currently, the problem with the largest amount of emissions is low-concentration, medium- and low-level waste, which is 1.
It is said that it can be considered that the eaves were taken down in about 2000.

In other words, the ideal land storage container would be one that would last about 100 years.

Currently, the main processing container for medium- and low-level radioactive waste is basically a stainless steel drum. For example, it is a multi-layered container in which the inside of a drum or gelatin can is lined with about 5 crrL of concrete, which is uniformly solidified with cement, asphalt, or the like. Drum containers are simple, relatively inexpensive, and have a good track record of use, but they corrode at 10 degrees and are unsuitable for long-term storage.

If it is stored indoors, it not only becomes difficult to handle it after corrosion, but also causes radiation exposure to workers and environmental pollution. However, if it is made of stainless steel, it is not only expensive but also deteriorates gradually over the long term, making it impractical.

Recently, the storage facilities at each nuclear power plant have become cramped.
The asphalt solidification method, which allows volume reduction and solidification at a relatively low cost, is attracting attention. However, solidified asphalt is undesirable because it easily burns in the event of a fire, and is even more dangerous if the F ram can corrodes.

Furthermore, in Japan, a country with a small land area, it is impossible to store radioactive waste permanently. It would be ideal to dispose of such waste, whose radioactivity has diminished after long-term storage, by dumping it in the ocean or burying it underground, so that storage sites can be used more effectively. Therefore, containers for land storage or land processing/disposal based on R-rum can containers are not preferred. In addition, polymer-impregnated concrete containers are made by impregnating and polymerizing monomers such as methyl methacrylate (MMA) into pre-formed concrete containers.
It is a superior container that has high strength, long-term durability, and can prevent radioactive materials from leaching. However, compared to ordinary concrete, impact resistance is not improved much and fire resistance is reduced. For this reason, shock accidents such as falls during transportation,
Concerns about disasters such as earthquakes and fires remain, so if containers for land processing and disposal are reinforced with appropriate materials, impact resistance, toughness, shear strength, fatigue resistance, etc. will be significantly improved. There is a problem with corrosion deterioration. Moreover, due to the characteristics at the time of manufacture, it is difficult to use it as a container for radioactive waste because it has the disadvantages of non-uniformity of fibers and lack of solidity of concrete, resulting in product variations.

In addition, in order to solve the above problems, we have developed a container for the treatment of radioactive waste and industrial waste, which is manufactured by impregnating a pre-formed steel fiber-reinforced concrete container with an impregnating agent such as a polymerizable monomer and then polymerizing and solidifying it in the concrete. has also been proposed, but there are many practical problems in terms of economy and quality stability. The container for radioactive waste cement solidification is
Conventionally, waste is solidified by stirring it together with a solidifying agent such as cement in a container. However, in the case of conventional stirring vessels,
When the stirring blade is removed after stirring is completed, a space corresponding to the volume of the stirring blade is formed in the upper part of the container. Therefore, it is necessary to fill this space with asphalt, mortar, etc.

[Problem that the invention seeks to solve]

The main object of the present invention is to provide a land treatment container for radioactive waste and industrial waste that has excellent strength, impact resistance, chemical resistance, fire resistance, corrosion resistance, economic efficiency, and quality stability.

[Means to solve problems]

That is, in the present invention, the inner surface is lined with concrete or mortar containing cementitious material, ultrafine powder, high performance water reducing agent, aggregate, and water as main components. It is a waste processing container.

The present invention will be explained in detail below.

The cementitious material referred to in the present invention refers to ordinary, early-strength, ultra-early-strength,
Commonly used are various types of Portolan cement such as white or sulfate-resistant cement, mixed cement mixed with admixtures such as blast furnace slag and fly ash, and mixed cement obtained by pulverizing the admixture and/or the cement to be mixed.

The ultrafine powder used in the present invention has an average particle size that is at least one order of magnitude lower than that of the above-mentioned cementitious material, and in particular, one that has an average particle diameter of two orders of magnitude lower is preferable from the viewpoint of flow characteristics of the mixed material. Specifically, silica dust (silica fume) and siliceous dust, which are produced as by-products during the production of silicon, silicon-containing alloys, and zirconia, are especially suitable.In addition, calcium carbonate, silica sol, opalescent silica, fly ash, and slag are suitable. Ultrafine powders such as , titanium oxide, and aluminum oxide can also be used. In particular, the use of ultrafine powder obtained by pulverizing opalescent silica, fly ash, or slag using a jet mill equipped with a classifier is effective in improving curing shrinkage.

The amount of ultrafine powder used is preferably 60 to 9
5 to 40 parts by weight, more preferably 6 parts by weight
It is 10 to 65 parts by weight relative to 5 to 90 parts by weight, and if it is less than 5 parts by weight, it is difficult to obtain high strength (fastness), and if it exceeds 40 parts by weight, the fluidity of the kneaded product will be significantly reduced. It becomes difficult to mold, and the strength development becomes insufficient.

The high-performance water reducing agent (hereinafter referred to as water reducing agent) used in the present invention is a surfactant with a large dispersion ability that does not cause too much delay in setting or excessive air entrainment even when added to cement in large quantities, and is Examples include salts of formaldehyde sulfonate, salts of formaldehyde melamine sulfonate, high molecular weight trigenine sulfonates, polycarboxylate salts, and the like. Water reducing agents are necessary to obtain mixed materials at low water ratios, and the conventional usage amount is
Although 0.6 to 1 weight F is used as a solid content for the cementitious material, in the present invention, it is preferable to add a larger amount than that. Specifically, it is used up to about 10 parts by weight as a solid content per 100 parts by weight of the mixture of cementitious material and ultrafine powder, and if a large amount of soot is added, it will adversely affect the curing reaction. A particularly preferable addition amount is 1 to 5 parts by weight. By using such a water reducing agent in combination with ultrafine powder, it is possible to obtain a fluid mixed material that can be molded by conventional methods even if the ratio of water cementitious material to ultrafine powder is less than 25%. can.

The water used in preparing the mixture in the present invention is necessary for molding, but in order to obtain a high-strength hardened product, it is best to use as little water as possible. It is preferably 12.5 to 60 parts by weight, more preferably 15 to 28 parts by weight. If the amount of water is more than 60 parts by weight, it is difficult to obtain a high-strength cured product, and if it is less than 12.5 parts by weight, -Jl part, it becomes difficult to perform ordinary molding such as pouring.

The aggregate used in the present invention may be any commonly used aggregate, but is preferably hard and has a high specific gravity, with a Mohs hardness of 6 or more, preferably 7 or more, or a Knoop indenter hardness of 700K.
Preferably, it is selected based on any of the following criteria: y/llm2 or higher. Examples of materials that meet this criterion are silica, pyrite, hematite, magnetite, pyrite, lawsonite, emery, corundum, zenasite, suginel, beryl,
Full curb stone, tourmaline, granite, andalusite, cross stone, zircon,
Calcined bauxite, charcoal-fired silicon, fused silica, fused magneitia, charcoal-fired silicon, cubic boron nitride, etc. are used.Especially in the case of containers for radioactive waste, the specific gravity of concrete is reduced to 6 by using iron powder, etc. .2 or more is preferable.

In addition to the above-mentioned materials, chemical admixtures commonly used in concrete or mortar may be used in combination as required.

The method of mixing and crossing the above materials is not particularly limited, and ordinary methods can be applied.

The lining method is a commonly used method, such as centrifugal lining, injection lining using an inner mold, and spray lining.

The shape of the processing container according to the present invention is generally a drum, but is not limited to this.

As a specific example, the present invention will be further explained based on an example using a P rum can.

The standard P ram can used in the present invention is a 2001f/4g drum JI8Z1 <500-1977H class (1-6 m), and reinforcing reinforcing bars are embedded in the inner surface of the P ram can as shown in Figure 1 to a thickness of 30 to 30 m. In step 701, a dense concrete having the above composition is lined. The concrete lining method is based on injection molding, in which uniformly mixed and dense concrete is injected into the gap between the inner formwork and the drum using methods such as injection using head pressure, injection using a pump, and pouring.

At this time, the mixed concrete is vacuum degassed,
By removing the air bubbles contained within the concrete, the compactness of the hardened concrete can be further improved.

In addition, the inner formwork may be filled with plastic molded products or stainless steel wire mesh, etc.
It can be selected appropriately considering economic efficiency and practicality.

The parts are first molded as one piece, and after filling with a certain waste material and solidifying it with cement or the like, the canopy part is molded and completed.

When forming the rice trunk and bottom part, the reinforcing bars to be buried in the canopy part are installed in advance, and when forming the canopy part, they are placed in one piece on the solidified waste without using an internal formwork. Pouring concrete. That is, according to the present invention, when radioactive waste is drum-canned with cement, the upper space formed after the stirring blades are removed after stirring is replaced with dense concrete when forming the canopy. .

〔Example〕

The present invention will be further explained below with reference to Examples.

Example 200! Steel drum CJIB Z 1600 class 8 (
1,6III): The inner formwork was set so that the lining thickness was 501 m.

In addition, as shown in the drawing, reinforcing reinforcing bars with a diameter of φ6 m/m are 20
Install it at GrIL intervals.

9. Make concrete with the mix shown in the table and pour it using a pump.9.

Steam curing was performed at 50°C for 12 hours. Afterwards, physical properties were evaluated. Based on the evaluation standards of the Japan Atomic Energy Research Institute, an impact test and an air tightness test were conducted on the lined drum tube.

As a result, there were no problems.

〔Effect of the invention〕

I got something with .

[Brief explanation of the drawing]

The drawing is a VFR diagram of a lined one-ram tube showing a variant of the invention.

Claims (1)

[Claims] A waste treatment container whose inner surface is lined with concrete or mortar whose main components are cementitious material, ultrafine powder, high-performance water reducing agent, aggregate, and water.