JPS58187900A - Method of storing solidified body of high level radioactive liquid 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 storing high-level radioactive waste liquid assimilate in nuclear facilities such as nuclear power plants.

The spent fuel of the nuclear reactor is processed at a reprocessing plant, and the raw waste liquid with high radioactivity level is treated as vitrified material, etc.
It is sealed and stored in a copper container called a canister. This canister and the solidified body are collectively referred to as an assimilation package, and the solidified package itself contains a high level of radioactivity as well as fissile material (F) in the vitrified body.

P,) collapses and generates decay heat. Since the decay heat may reach a high temperature, there is a risk that the vitrified material may decompose in the bath, causing damage to the canister and causing accidents such as radioactivity leakage. Part 11. Therefore, solidified packages must be stored with heat removed under a high degree of safety and reliability.

Conventional cooling methods for solidified packages include various methods such as natural air cooling, forced air cooling (or water cooling), and the like.

In the natural air cooling method, as shown in Figure 1, the air intake (α
) The temperature of the cooled air sucked in increases due to the heat generated by the solidification package (C) housed in the cooling bit (b), and rises through the cooling pitch (6) due to the draft force.
After the assimilation package (BL) is cooled, it is released into the atmosphere. However, with this method, if radioactive substances leak, they will be released directly into the atmosphere and may cause air pollution, so filters should be removed. Although it is necessary to use a filter, the amount of cooling air generated by the draft fan will decrease, making it impossible to sufficiently cool the solidification package (c).
(Cl is easily overheated by decay heat, and radioactive materials are
It can easily leak, creating a huge safety problem.

In the forced air cooling method, a filter (d) is used as shown in Figure 2.
A cooling fan (g) is installed downstream of +, and air intake 1'l
Inhale cooling air from (α) and solidify the package (c)
The liquid is forced to rise and pass through the cooling pit 1-(b) containing the liquid, and after passing through the filter (d), it is released into the atmosphere. In this case, the assimilation package (c) must be stored for a long time (up to 100 years) because it is necessary to wait for the decline of F and P, and the cooling fan (g) requires power and cannot be operated. This poses a problem in terms of cost. The same applies to forced water cooling methods, especially the necessity of long-term water quality control and the generation of a large amount of secondary waste liquid if radioactive materials leak, etc., which is not the case with the conventional method of cooling solidified packages. This was done for the purpose of eliminating the problem with the law, and by making the storage chamber of Assimilation Pasoké 7 into a closed cycle and allowing the cooling air to circulate naturally within the closed cycle, the cooling air can be directly heated to a high temperature. ) This is a method for storing high-level radioactive solidified liquid waste that improves safety without emitting radioactivity, reduces operating costs, and makes it possible to utilize the waste heat.

Hereinafter, embodiments of the present invention will be described with reference to FIG. 1a.

FIG. 6 shows 1,! used in the embodiment of the present invention. ! This figure shows an example of a cooling device for a unitized bath kettle, in which a required number of vertical cooling bits (2) capable of storing a suitable number of solidification packages (1) in series are arranged in storage racks (
3) Provided within the storage rank (3)
Blenheims (4) and (5) are formed in the upper and lower parts of (3) and sealed with panels so as to form a storage (6) moxibustion.
4), a pipe line (7) is provided which communicates with the upper blenheim (5), and a heat exchanger (8) is provided in the middle of the pipe line (7).

The cooling air is stored in the storage (6) and the pipe (7) in a sealed state, and when F and P in the vitrified body of the solidification package (1) collapse and generate decay heat. , the cooling air in the cooling pit (2) rises through the heating tube (2) and reaches the two-part blenheim (4) while cooling the assimilation pancage (1).

The heated cooling air that collects in the two-part Blenheim ``4'' enters the pipe (7), exchanges heat with the cooling water in the heat exchanger (8), and flows further downward into the cooling coil 1. The cooling air collected in the lower plenum (5) enters the cooling bit (2) again and is transferred to the solidification package (
While cooling 1), it heats up and rises by 1t, reaching the second part of Blenheim (4).

In this way, the cooling air undergoes natural convection in the order of lower plenum (5) -> cooling pit (2) -> Dobe blennium (4) -> pipe (7) -> lower plenum (5) and is released to the outside air. I L
It's not enough. The heat from the solidification package (1) is recovered by the heat exchanger (8) and used for district heating, etc.

FIG. 4 shows another example of the assimilation cage cooling device used in the embodiment of the present invention, in which the solidification package (1)
A storage rank (3) equipped with the required number of cooling bits (2) that can store the cooling bits (2) in series, and a Blenheim (4) at the top and bottom.
(5) A channel (9) is formed on the side of the storage (6), which is sealed with a panel to form a storage (6), and a side wall (10) of the storage (6) is formed. cooling panel (1)
) is provided.

Since the cooling air is sealed in the storage (6), the cooling air in the lower blenheim (5) takes heat from the solidified package (1) in the cooling bit (2), increases the temperature, and cools the cooling bit (1). (2) and rises within it to reach the upper Blenheim (4). ” The heated cooling air that collects in the second part frenum (4) is stored.
□Cooling panel (11) installed on the side wall (10) of the storage (6)
) flows downward in the channel (9) while being cooled by t1
Leading to the lower Blenheim (5). The cooling air gathers in the lower blemish (5); it then enters the cooling bit (2) and cools the assimilation machine (1) while heating itself.
It rises to 1C1 + Blenheim (4).

In this way, the cooling air flows from the lower plenum (5) to the 1st instar.
1.11 Pill-(2)-→-"Partial plenum(4)→
Natural convection occurs in the flow path (9)→1・-) section Blenheim 75) (↓), and heat is removed from the solidification/ζ cage (1).

It should be noted that the method of storing high-level radioactive waste liquid assimilate according to the present invention is not limited to the above-described embodiments, and it goes without saying that various changes can be made without departing from the gist of the present invention.

As described above, 71. (1) A closed circulation system is used in which the cooling air used to remove heat from the solidified package in the cooling bit is cooled and solidified again, and is used to cool the sock cage, eliminating the need to use a filter and improving solidification.・Able to efficiently cool the wood cage.

(n) By cooling the assimilation package and recirculating the cooling air without directly releasing it into the atmosphere, safety is ensured by 1% even if radioactive materials leak from the solidification package.

([LD) Since natural convection is used, no power is required to operate the cooling fan. Therefore, the operating cost is low and it is suitable for storing assimilation packages for a long period of time. -4- If water is used as the indirect cooling medium, there is a possibility that a jminp for that purpose will be required.
In that case, the iE conversion cost (well, it will be cheaper than the operating cost of the cooling fan).

LIV) If a heat exchanger is installed, assimilation package power
This makes it possible to use the waste heat for, for example, district heating or water supply preheating.

It exhibits various excellent effects such as.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a conventional apparatus used for cooling an assimilated package, FIG. 2 is an explanatory diagram of another example of a conventional apparatus used for cooling a solidification package, and FIG. 6 is an explanatory diagram of another example of a conventional apparatus used for cooling a solidification package. An explanatory diagram showing an example of a cooling device for a solidification package to be used,
FIG. 4 (This is an explanatory diagram showing another example of a cooling device for a solidification package used in the method of the present invention. In the figure, (1) is a solidification package, (2) is a cooling bit,
(4) (5) indicates a plenum, (7) indicates a pipe line, (8) indicates a heat exchanger, (!l) indicates a flow path, and 01) indicates a cooling panel. Patent applicant Ishikawajima Harima Heavy Industries Co., Ltd.

Claims (1)

[Claims] Cooling air that enters from below the cooling pin is heated and rises inside the cooling bit, forming a sealed space in which heated cooling air exiting from two sides of the cooling bit is cooled and re-enters from below the cooling bit. and storing a radioactive waste liquid assimilate in the cooling bit in such a way that decay heat from the radioactive waste liquid assimilate can generate a flow of cooling air in the cooling bit. Method of storing solidified material.