JPS61111494A - Irradiation agent fuel storage facility - 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] (Industrial application field) The present invention relates to irradiation method fuel storage equipment.

(Prior art) During periodic inspections of nuclear power plants, irradiation method fuel assemblies taken out from the reactor are placed in the irradiation method installed in the spent fuel pinto in the fuel handling building adjacent to the reactor containment vessel. The fuel is stored in a finished fuel rack and stored. To explain the conventional example of the irradiated fuel storage equipment according to Section 9.10, the irradiated fuel storage equipment has a large number of rack cells (1) for storing spent fuel assemblies, and each rack cell (1) is welded. It consists of a large number of supporting members (21) that are attached to each other and connected to each rack cell (1), and the end of each supporting member (2) is connected to the bracket (5) of the embedded fitting (4) of the focus wall 3. ).Each of the above rack cells (1) is attached to the 11th rack cell (1).
．． As shown in Figure 12, the cell (1α) and fuel guide (1
b), a base plate (1), and a fuel stopper (1d), and cooling water inlet holes (1g) are provided on the four sides of the lower end of the cell (1α). The irradiated fuel that has just been stored in rack cells (1) is heated with residual heat, and the water in the rack cells (1) is heated and rises, then flows down between the rack cells (1), and the temperature decreases. The irradiated fuel is cooled by the natural circulation of water entering the rack cell (1) through the cooling water inlet hole (1).

(Problems to be Solved by the Invention) In the irradiated fuel storage facility, the irradiated fuel pit αη shown in FIG. However, in the unlikely event that for some reason, such as water leakage or evaporation due to fire, the irradiated fuel in the irradiated fuel pit (when the water in lη runs out, the adjacent one) becomes critical. I rarely had problems reaching it.

(Means for Solving the Problems) The present invention addresses the above-mentioned problems, and has a neutron absorption capacity in the spaces between the rack cells of the irradiated fuel rack and the spaces between the rack cells and the focus wall. 11 Pour ready-mixed concrete containing large substances into a concrete wall and solidify to form a concrete wall, a heat exchanger, a conduit that leads the cooling water from the heat exchanger to the bottom of the rack cell, and the cooling water from the conduit. A cooling water circulation system similar to a circulation pump that pumps up between the irradiated fuel rack and the rack cell and through the upper part of the pit and sends it to the heat exchanger, as well as empty rank cells and cooled irradiated fuel, are stored there. The present invention relates to an irradiated fuel storage facility characterized by comprising a plug for sealing a rack cell, and its purpose is to quickly cool irradiated fuel. It also provides an improved irradiated fuel storage facility that can ensure subcriticality even when the water in the pit runs out.

(Example) Next, the irradiated fuel storage equipment of the present invention will be explained using an example shown in FIGS. 1 to 8. A rack cell (1) is attached to a support member (2) by welding. , each rack cell (
1), and the end of the support member (21) is attached to the bracket (5) of the embedded metal fitting (4) of the pit wall (3) to form a rank. Also, between each rack cell (1) The upper end of the space between the space and each rank cell (1) and the pit wall (9) is covered with a frame plate, the lower end is covered with a frame plate (6), and the same frame plate (7) is covered. Concrete containing a material such as boric acid or gad IJ = ram with high neutron absorption capacity (9) is poured into each of the above spaces from air venting epiphytic concrete injection holes α1 provided at appropriate locations, and after hardening, air venting is performed. The concrete injection hole α1 is sealed with a lid (10). Each rack cell (1) is equipped with a fuel stopper (1d) as shown in Figure 9.10, taking into consideration the circulation of cooling water described later.
) and the bottom is missing. In this case, each rack cell (
1) The gap between the gaps is filled with concrete and disappears.
Since the irradiated fuel assemblies cannot be cooled by the natural circulation of water in the pit, a cavity (Is) is provided below the rank cell (1), and the cooling water is forcibly circulated there to cool the irradiated fuel assemblies. It is necessary to remove the residual heat that the cooling water has.The cooling water circulation system is explained in Figure 6.
The space between 11 and each rack cell (1) and pit wall (9
A concrete wall (9) is formed in the space between the two walls, as shown by parallel diagonal lines. The water at the top of this concrete (9) that left the rank cell +1j between the walls is
The cooling water suction conduit (12
→ It is guided through the circulation pump Q411t to the heat exchanger, where it is cooled, and then it is discharged to the cavity below each rank cell (1) through the cooling water discharge conduit (11Jt).
In addition, the cooling water discharged to the convex cavity α4 is
-) (91 rises inside the rack cell (1) between the walls, exits the upper part of the pit αD, and circulates. Q61 in Fig. 8 is a heavy plug made of steel etc. Then, the same plug αe is in the empty rack cell (1), the cooled irradiated fuel c!IIIf, and the rack cell in which it is stored (
1), these rack cells are sealed.

(effect) Next, the operation of the irradiated fuel storage facility will be explained.

As shown in Figure 8, in the rack cell (1) between the concrete (9) wall, (I) an empty one (see (1)) and (II
) The one that stores the already cooled irradiated fuel OQ, and the one that stores the fighting irradiated fuel (2
1) If you encounter something that is stored in t- (I) (n
) is sealed with a plug αe. In this state, heat exchanger a4 → cooling water discharge conduit (1
11 → Cavity part α → Inside rack cell (1) → Top of Pitsu H7) → Cooling water suction conduit α2 → Circulation pump α → Cooling water circulating to heat exchanger a4 goes to 2 cells (1) of (1) The warm irradiated fuel (r2I) is cooled down quickly by rising only inside. In addition, pit walls other than those with concrete (9) walls (part 99) are lined with stainless steel (3).
Two measures have been taken to prevent water leakage.

(Effects of the Invention) As described above, the irradiation source fuel storage equipment of the present invention has ready-mixed concrete containing a substance with high neutron absorption capacity in the space between the rank cells of the irradiated fuel ranks and the space between the rack cells and the pit wall. A concrete wall formed by pouring free fuel and solidifying it, a heat exchanger, a conduit that guides cooling water from the heat exchanger to the bottom of the rack cell, and a conduit that directs the cooling water from the conduit to the irradiated fuel rack and rack cell. A cooling water circulation system such as a circulation pump that pumps up water through the space and the upper part of the pit and sends it to the heat exchanger, and empty rank cells and cooling 1
The irradiated fuel will be stored in the “Ruu 7 Ri”
Since the above action is performed, the irradiated fuel can be cooled quickly. In addition, there is a concrete wall formed by pouring ready-mixed concrete containing a material with high neutron absorption capacity into the space between two rack cells of irradiated fuel rank and the space between the rack cell and the pit wall and solidifying it. Furthermore, even if the water in the pit runs out for some reason, there is no danger that the adjacent irradiation tower assemblies will reach criticality.

Although the present invention has been described above with reference to embodiments, it goes without saying that the present invention is not limited to any embodiment, and that various design modifications can be made without departing from the spirit of the present invention. .

[Brief explanation of drawings]

FIG. 1 is a plan view showing an embodiment of an irradiation source fuel storage facility according to the present invention, FIG. 2 is a vertical side view thereof, and FIG. 3 is a cross-sectional plan view taken along the arrow n-I line in FIG. , FIG. 4 is a vertical side view taken along the arrow ff-IT line in FIG. 11 is a plan view showing a conventional irradiation source fuel storage facility, FIG. 11 is a side view thereof, FIG. 13 is a plan view of a rank cell, and FIG. 14 is a longitudinal sectional side view thereof. (11... rack cell, (9)... concrete wall, (9... pit wall, αB... conduit, (13...
・Heat exchanger, (14)...Circulation pump, (1e...
Plug, αη...pit. Sub-Agent Patent Attorney: Shige Okamoto (3 persons)

Claims (1)

[Claims] A concrete wall formed by pouring and solidifying fresh concrete containing a material with high neutron absorption capacity into the space between the rack cells of the irradiated fuel rack and the space between the rack cell and the pit wall, and the heat exchanger. A conduit that guides the cooling water from the heat exchanger to the lower part of the rack cell, and a circulation pump that pumps up the cooling water from the conduit between the irradiated fuel rack and the rack cell and through the upper part of the pit and sends it to the heat exchanger. 1. An irradiated fuel storage facility comprising: a cooling water circulation system; and a plug for sealing an empty rack cell and a rack cell storing cooled irradiated fuel.