JP2009229411A - Heat insulator for core domain in reactor pressure vessel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the radiation dose in a core domain, by imparting a radiation shielding function to a heat insulator for the core domain, in a reactor pressure vessel. <P>SOLUTION: The heat insulator for the core domain in the reactor pressure vessel is shaped like divided panels. Each of the panels is made into a heat-insulating member 4a composed by making a lead plate 15 and a metal foil 7 a multi-layered structure, in between an outside plate 5 and an inside plate 6 and forming empty spaces 9 between layers. The heat-insulating members 4a are arranged circumferentially and vertically, and adjoining members 4a are coupled to one another, to make them into heat insulators. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a heat insulating material for reducing the radiation dose from a reactor pressure vessel (RPV) installed and used in a reactor containment vessel, and more particularly to a heat insulating material in a core region. .

  As a structure of a nuclear reactor, generally, a reactor pressure vessel (RPV) is positioned at a core portion, and a metal RPV heat insulating material and a reactor containment vessel (PCV) are sequentially positioned on the outer side. It is as. The RPV heat insulating material installed so as to cover the entire circumference of the reactor pressure vessel is mainly intended to keep the temperature of the reactor pressure vessel. By maintaining the temperature of the reactor pressure vessel, the reactor It is intended to improve the thermal efficiency (power generation efficiency) of the pressure vessel.

  FIG. 4 shows the relationship between the reactor pressure vessel 1 and the metallic RPV heat insulating material 2 located outside the reactor pressure vessel 1, and the RPV heat insulating material 2 is spaced apart from the reactor pressure vessel 1 by a required interval. It is installed over the entire circumference so as to keep the reactor pressure vessel 1 warm.

  FIG. 5 shows an example of a process of incorporating the reactor pressure vessel 1 into the reactor containment vessel (PCV). The metal heat insulating material 2 is attached so as to form a required gap outside the reactor pressure vessel body 1a. Further, the gap between the reactor pressure vessel body 1a and the metal heat insulating material 2 is filled with high-density mortar 3 to be shielded (see, for example, Patent Document 1).

  The metal heat insulating material 2 shown in FIG. 4 and FIG. 5 is divided into panels having a required size as shown in the right half of FIG. 4, and the heat insulating plate member 4 as each divided panel is circumferentially divided. The heat insulating plate members 4 adjacent to each other in the vertical direction and the left and right (circumferential direction) are joined together to be integrated.

  As shown in FIGS. 6 and 7, the divided heat insulating plate member 4 is made of aluminum having a bent portion 8 in the middle between an outer plate 5 and an inner plate 6 arranged to face each other at a required interval. The metal foil 7 such as stainless steel is laminated in multiple layers in the inner and outer directions, and a space portion 9 is formed between the metal foils 7 of each layer so as to have a heat retaining effect. And the left and right side end faces are closed by the side closure 11.

  In FIG. 6, 12 is a handle attached to the outer surface of the outer plate 5 in order to facilitate handling when assembling the heat insulating plate member 4 as each panel, 13 is an overlap, and 14 is an adjacent heat insulating plate member. It is a buckle for connecting each other.

JP 2005-308627 A

  However, in a reactor having a structure in which the RPV insulation is positioned outside the reactor pressure vessel and the reactor containment vessel is located outside the reactor pressure vessel, the radiation from the reactor pressure vessel is transmitted to the reactor containment vessel. It is supposed to prevent. Therefore, the actual condition is that the reactor containment vessel has a structure capable of shielding radioactivity. On the other hand, the heat insulating material is mainly intended to keep the temperature of the reactor pressure vessel, and the role of shielding radioactivity was not great.

  Therefore, for example, when an operator approaches the nuclear pressure vessel in order to adjust the piping at the time of inspection or the like, sufficient protective measures are taken to prevent exposure. In particular, in the reactor core region where the fuel rods are located inside the reactor pressure vessel, water is evaporated with the energy obtained by the reaction, and the turbine is powered by steam to generate electricity. The amount is high. It is necessary to pay close attention not to be exposed when an operator enters between the containment vessel and the reactor pressure vessel during inspection.

  Therefore, the present invention provides radiation insulation to the outside of the reactor pressure vessel so that the insulation material positioned outside the core region of the metal insulation material that keeps the temperature of the reactor pressure vessel has a radiation shielding function. Try to reduce the amount.

  In order to solve the above-mentioned problems, the present invention forms a space between the inner plate and the outer plate by laminating metal foils between the inner plate and the outer plate in a multilayered manner. A heat insulating plate member formed by forming a layer of a shielding portion with a high specific gravity member at a required location is configured to be a heat insulating material positioned outside the core region of the reactor pressure vessel.

  Further, the heat insulating plate member is configured to be laminated by combining a plate of a high specific gravity member with a metal foil between the inner plate and the outer plate.

  Further, the heat insulating plate member is configured to be loaded or filled in a space portion between arbitrary metal foils by using a high specific gravity member as a plate or a sphere between the inner plate and the outer plate.

According to the present invention, the following excellent effects are exhibited.
(1) A metal foil is laminated in multiple layers between an inner plate and an outer plate to form a space between the respective layers, and at a required portion between the inner plate and the outer plate is shielded by a high specific gravity member. The heat insulating plate member formed by forming a layer of a portion is configured to be a heat insulating material positioned outside the core region of the reactor pressure vessel, and the heat insulating plate member is formed of an inner plate and an outer plate. A structure in which a plate of a high specific gravity member is laminated in combination with a metal foil, or a heat insulating plate member, between the inner plate and the outer plate, the high specific gravity member as a plate or a sphere, between any metal foil Since the space portion is loaded or filled, the thermal insulation material in the core region can have the performance of thermal insulation and radiation shielding, and the radiation dose in the core region can be reduced. it can.
(2) The radiation exposure of the operator can be reduced by the above (1), and radiation leakage can be reduced not only during the normal operation of the reactor but also when an accident occurs.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  The present invention is located on the outside of the nuclear pressure vessel 1 shown in FIG. 4, and among the metal heat insulating materials 2 that keep the nuclear pressure vessel 1 warm, in particular, the core of the reactor pressure vessel 1. A member having a high specific gravity such as lead is incorporated in the heat insulating material 2 located outside the region A (see FIG. 4) so that the heat insulating material 2 in the core region A has the performance of heat insulation and radiation shielding.

  More specifically, FIG. 1 shows an embodiment of the present invention. The heat insulating plate member 4 shown in FIGS. 6 and 7 constituting the heat insulating material 2 positioned outside the core region A, and In a similar configuration, among the plurality of metal foils 7 laminated from the inside to the outside in the required gap between the inner plate 6 and the outer plate 5, for example, instead of the metal foil 7 located in the odd layer, the middle Incorporating a flat lead plate 15 which has a bent portion formed therein to function as a spacer, and a space 9 is formed between the lead plate 15 and the adjacent metal foil 7. Let it be the plate member 4a. Further, the heat insulating plate member 4a is arranged in the circumferential direction and the vertical direction in the core region A, and the adjacent heat insulating plate members 4a are connected to each other so as to have a required size and width. And

  Other configurations are the same as those shown in FIGS. 6 and 7, and the same components are denoted by the same reference numerals.

  Each of the heat insulating plate members 4a constituting the heat insulating material in the core region of the present invention is configured such that the lead plate 15 and the metal foil 7 are laminated at a predetermined interval, and a space portion 9 is formed between the respective layers. Therefore, each of the heat retaining plate members 4a can keep the temperature of the reactor pressure vessel 1 in the same manner as in the conventional case, and also incorporates a lead plate 15 to provide a shielding portion 16 to provide a radiation shielding function. At the same time, it can have a radiation shielding performance. Thereby, the radiation dose can be reduced outside the heat insulating material located outside the core region A, and the radiation exposure of the operator can be reduced.

  Next, FIG. 2 shows another embodiment of the present invention. In the same configuration as the conventional heat insulating plate member 4 shown in FIGS. 6 and 7, the space between the metal foils 7 of the required layer is shown. 9, a lead plate 17 is inserted and laminated.

  That is, instead of incorporating the lead plate 15 shown in FIG. 1 between the layers of the metal foil 7 to form a multilayer structure, a lead plate 17 having an increased thickness is loaded into the required space 9.

  The lead plate 17 may have only one layer.

  Also in this embodiment, since the shielding portion 16 is provided by the lead plate 17, the same effect as in the embodiment shown in FIG. 1 can be obtained.

  Next, FIG. 3 shows still another embodiment of the present invention. In the embodiment shown in FIG. 2, lead is provided in a required space 9 between the multilayer metal foils 7 constituting the heat insulating plate member 4a. Instead of the configuration in which the plate 17 is loaded, a large number of lead spheres 18 formed into a spherical shape are filled in a required space portion 9 to provide a shielding portion by the lead spheres 18. .

  Other configurations are the same as those shown in FIGS. 1 and 2, and the same components are denoted by the same reference numerals.

  Even in this embodiment, the same effects as those shown in FIGS. 1 and 2 can be obtained.

  The present invention is not limited to the above-described embodiment. In the embodiment shown in FIG. 1, only one lead plate 15 may be provided, and all the metal foils 7 may be provided. Instead, a lead plate 15 may be used. Further, in the case of the embodiment shown in FIGS. 2 and 3, the case where the shield part by the lead plate 17 and the lead sphere 18 is formed every other layer is shown, but the shield part has only one layer. 1 or 3 as an embodiment of the present invention, but a shielding part made of lead is formed. As long as there is any structure, lead is exemplified as a material having a high specific gravity, but as long as it has heat resistance, it may be other than lead, and various other within the scope of the present invention. Of course, changes can be made.

It is a cut side view of the heat insulation board member which shows an example of one Embodiment of this invention. It is a figure corresponding to FIG. 1 which shows an example of the other form of implementation of this invention. It is a figure corresponding to FIG. 1 which shows an example of the further another form of implementation of this invention. It is a partially cut side view which shows that the RPV heat insulating material is located in the outer side of the nuclear reactor pressure vessel. It is a figure in one process of the exchange operation | work of the conventional nuclear reactor pressure vessel. It is a perspective view of each heat insulating board member which comprises the conventional RPV heat insulating material. FIG. 7 is a cut side view of the heat insulating plate member of FIG. 6.

Explanation of symbols

1 Reactor pressure vessel 2 RPV thermal insulation (thermal insulation)
4a Insulating plate member 5 Outer plate 6 Inner plate 7 Metal foil 8 Bending portion 9 Space portion 15 Lead plate 16 Shielding portion 17 Lead plate 18 Lead sphere

Claims (3)

  A metal foil is laminated in multiple layers between the inner plate and the outer plate to form a space between each layer, and a layer of a shielding portion by a high specific gravity member is provided at a required portion between the inner plate and the outer plate. A heat insulating material in the core region of the reactor pressure vessel, characterized in that the heat insulating plate member formed of is used as a heat insulating material positioned outside the core region of the reactor pressure vessel.   The heat insulating material in the core region of the reactor pressure vessel according to claim 1, wherein the heat insulating plate member is laminated between the inner plate and the outer plate by combining a plate of a high specific gravity member with a metal foil.   The core of a reactor pressure vessel according to claim 1, wherein the heat insulating plate member is loaded or filled in a space portion between any metal foils with a high specific gravity member as a plate or a sphere between the inner plate and the outer plate. Area insulation.

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