JPS6013289A - Storage facility for fuel of nuclear reactor - 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 Application of the Invention] The present invention relates to a fuel storage facility for a nuclear reactor that stores nuclear fuel assemblies used in a nuclear power plant.

[Background of the invention′]

At a nuclear power plant, spent fuel removed from the reactor core is temporarily stored underwater in a spent fuel pool installed inside the reactor building until it is transported to a reprocessing plant. . Due to delays in spent fuel reprocessing, improvements have been made in recent years to shorten the interval between stored fuels in order to make full use of the space within the spent fuel pool (hereinafter referred to as the pool). The fuel storage racks (hereinafter referred to as ranks) are referred to as high-density ranks.

Figure 1 shows the water depth breakdown of the cross section of the pool where the ranks of boiling water reactors are installed. The pool has a depth of about 11.5 m, and its configuration is: storage fuel height a1 storage fuel/transfer fuel clearance b1 transfer fuel height C1 transfer fuel shielding water depth d, each of which is approximately 4.6 m.

0.2 m, 4.5 m, 2. 'l, m. Therefore, compared to the stored fuel height of 4.6 m, it is approximately 2.5 m.
The water depth would need to be doubled, and there is still room for improvement in terms of effective use of space.

[Purpose of the invention]

An object of the present invention is to provide a facility capable of high-density storage with respect to pool volume, and aims to reduce the conventional fuel transfer height and increase the storage amount by stacking ranks in multiple stages.

[Summary of the invention]

The reactor fuel storage facility of the present invention stores spent fuel (hereinafter referred to as fuel assembly) in horizontal stacking ranks.

Storage efficiency has been improved by transporting and installing the rank horizontally.

Furthermore, by forcing the coolant to flow, it is possible to stack fuel assemblies Q horizontally, and the storage efficiency is completely improved by grading the ranks.

[Embodiments of the invention]

An embodiment of the present invention will be described in detail below with reference to FIGS. 2 to 9.

Figure 2 shows an example of a rack for horizontal loading, with rank support parts 4,
This is a stacking rack 6 consisting of a slip-off prevention frame 5 that maintains the alignment of fuel assemblies and prevents them from slipping down. A water spray pipe 7 for forced cooling is located in the axial direction of the fuel collector. Compared to Fig. 1, the water depth is calculated by omitting the transfer height C, and by increasing the fuel rod height a.
has been replaced by the rank height e. Also, a and e'(
+? In comparison, e can be freely determined at the design stage, whereas a=4.5m, and it is possible to sufficiently set e (a).

FIG. 3 is a front view of the slip-off prevention frame 5 in FIG. 2. The diagonal member 8 prevents the fuel assembly from slipping down, and the mounting portion 9 fixes it to the main body. 10 is the upper part of the fuel assembly, and when viewed from the side, the state is as shown in FIG.

FIG. 5 shows the situation when the fuel assembly is stored. Rollover device 1
The fuel assembly 2 is stored in the rank 1. After storage, the slip-off prevention frame 5 shown in FIG. 3 is attached, and the rank is turned sideways using the overturning device 11'. (When setting ranks, do the opposite operation.) The required water depth for the pool in the state shown in Figure 5 is the same as before, but when the ranks are placed horizontally as shown in Figure 6, the water depth is As shown in Figure 2, it can be made shallower than before. In other words, as shown in Figure 7, as shown in Figure 1, if a fuel storage pit with the same water depth as the conventional one is installed, and a crane is used to transport and store the fuel with the rank lying on its side, the water depth of the storage pool will be reduced. As shown in Figure 2, the water can be made shallower than before.

FIG. 8 shows the state of multi-stage stacking. Since the water depth is two-tiered, the rank height e is doubled, and the transfer fuel clearance b-
From i to water depth d, it becomes b+d+2 e. Compared to FIG. 2, the water depth has been added to the rank height e, but the storage density has increased. Regarding the stability issue of the rank, the rank height e in the axial direction of the fuel assembly is sufficiently small, and the circumference around the axis can also be taken into consideration at the design stage, and if the rank width f2 is made large, it becomes safe against overturning.

Figure 9 shows the conventional case where fuel assemblies are stored vertically,
It is a diagram of combined use with horizontal stacking ranks. a, b, c in the figure,
d and e are the water depth breakdown, which respectively mean the stored fuel height, storage fuel/transfer fuel clearance, transferred fuel height, transfer shielding water depth, and horizontal stacking rank height. The right side shows the conventional water depth breakdown. From the figure, a + c > a + e +. This means that if the necessary equipment is provided for the horizontal stacking ranks, it is possible to use the transfer fuel height in a conventional fuel storage pool to store two stacks of fuel and make better use of the space.

〔Effect of the invention〕

According to the present invention, the space within the pool can be used effectively,
This makes it possible to provide inexpensive fuel storage equipment for nuclear reactors, and is effective in reducing costs.

[Brief explanation of the drawing]

FIG. 1 shows a breakdown of water depth in the cross section of a conventional spent fuel pool. FIG. 2 is a pool cross-sectional water depth breakdown using horizontal stacking ranks, FIG. 3 is a sectional view taken along line A-A in FIG. 2, and FIG. 4 is a side view of FIG. 3. Fig. 5 is a cross-sectional view showing the fuel assembly stored state, Fig. 6 is a state diagram with the rank laid down using the overturning device, and Fig. 7 is a sectional view showing the fuel assembly stored state.
The figure is a cross-sectional water depth breakdown diagram of the fuel assembly storage bit and storage pool. FIG. 8 is a cross-sectional water depth breakdown diagram of two horizontally stacked ranks, and FIG. 9 is a cross-sectional water depth breakdown diagram where a horizontally stacked rank is placed on top of the conventional rank. l... Spent fuel storage pool, 2... Spent fuel assembly, 3... Spent fuel storage rank, 4... Rank support for horizontal loading, 5... Slip prevention frame , 6...Rack for horizontal stacking, 7...Water pipe, 8...Slip prevention frame diagonal material, 9...Fixing part between rank for horizontal stacking and slip-down prevention frame, 10... Upper part of fuel assembly, 11... Overturning device, a... Storage fuel assembly height, b =... Storage fuel.
Transfer fuel clearance, C...Transfer fuel height, d...
・Transfer shielding water depth, C...Rank height for horizontal loading, f・
... Horizontal loading run Figure 1 Figure 2 Figure 3 Figure 4 Figure S Figure q Figure ε Figure

Claims (1)

[Claims] 1. Holding a plurality of fuel assemblies in alignment in a horizontal state;
A nuclear reactor fuel storage facility characterized in that support portions with good water permeability are provided at both ends of the fuel assembly. 2. The nuclear reactor fuel storage facility according to claim 1, characterized in that a forced cooling flow is generated from one end of the stored fuel to the other end.