The invention is applicable to the corium localizing and cooling systems of a nuclear reactor designed for localization of severe beyond design-basis accidents, in particular, to the devices for directing corium of a nuclear reactor to the corium trap. The technical result of the claimed invention is to increase the efficiency of localization and cooling of the nuclear reactor core melt.

The goal of the invention is to eliminate the guide assembly failure due to the concentration of impact load in the conical part of the guide assembly and, therefore, the instantaneous penetration of the core, fragments of the reactor vessel internals and the reactor vessel head into the core catcher.

According to the claimed invention, the guide assembly of the nuclear reactor corium localizing and cooling system installed under the reactor vessel and supported on the cantilever truss contains a cylindrical part, a conical part with an opening made in it, with their walls covered with heat-resistant and fusible material and divided into sectors by bearing ribs arranged radially relative to the opening, and a bearing frame consisting of the outer upper bearing ring, the outer lower bearing ring, the inner bearing shell, the outer upper bearing shell, the middle bearing shell divided into sectors by bearing ribs, the outer lower bearing shell, support ribs, base, upper inclined plate connecting the conical head, bearing ribs and the middle bearing shell, lower inclined plate connecting the conical head, bearing ribs, the middle bearing shell and the outer upper bearing shell.

3 claims, 4 figures of drawings

The invention is applicable to the corium localizing and cooling systems of a nuclear reactor designed for localization of severe beyond design-basis accidents, in particular, to the devices for directing corium of a nuclear reactor to the corium trap. The technical result of the claimed invention is to increase the efficiency of localization and cooling of the nuclear reactor core melt.

The goal of the invention is to eliminate the guide assembly failure due to the concentration of impact load in the conical part of the guide assembly and, therefore, the instantaneous penetration of the core, fragments of the reactor vessel internals and the reactor vessel head into the core catcher.

According to the claimed invention, the guide assembly of the nuclear reactor corium localizing and cooling system installed under the reactor vessel and supported on the cantilever truss contains a cylindrical part, a conical part with an opening made in it, with their walls covered with heat-resistant and fusible material and divided into sectors by bearing ribs arranged radially relative to the opening, and a bearing frame consisting of the outer upper bearing ring, the outer lower bearing ring, the inner bearing shell, the outer upper bearing shell, the middle bearing shell divided into sectors by bearing ribs, the outer lower bearing shell, support ribs, base, upper inclined plate connecting the conical head, bearing ribs and the middle bearing shell, lower inclined plate connecting the conical head, bearing ribs, the middle bearing shell and the outer upper bearing shell.

3 claims, 4 figures of drawings

The invention is applicable to the corium localizing and cooling systems of a nuclear reactor designed for localization of severe beyond design-basis accidents, in particular, to the devices for directing corium of a nuclear reactor to the corium trap.

The technical result of the claimed invention is to increase the efficiency of localization and cooling of the nuclear reactor core melt.

The goal of the invention is to eliminate the guide assembly failure due to the concentration of impact load in the conical part of the guide assembly and, therefore, the instantaneous penetration of the core, fragments of the reactor vessel internals and the reactor vessel head into the core catcher.

In accordance with the invention, the guide assembly of the corium localizing and cooling system installed under the reactor pressure vessel and resting on the cantilever truss apart from the load-bearing frame contains the thermal elements that in the aggregate allows providing guaranteed entry of core, debris of the internals and the head of the reactor pressure vessel into the corium trap by excluding melt-through of the walls of conical and cylindrical parts and by redistributing the corium jet streams.

The invention is applicable to the corium localizing and cooling systems of a nuclear reactor designed for localization of severe beyond design-basis accidents, in particular, to the devices for directing corium of a nuclear reactor to the corium trap.

The technical result of the claimed invention is to increase the efficiency of localization and cooling of the nuclear reactor core melt.

The goal of the invention is to eliminate the guide assembly failure due to the concentration of impact load in the conical part of the guide assembly and, therefore, the instantaneous penetration of the core, fragments of the reactor vessel internals and the reactor vessel head into the core catcher.

In accordance with the invention, the guide assembly of the corium localizing and cooling system installed under the reactor pressure vessel and resting on the cantilever truss apart from the load-bearing frame contains the thermal elements that in the aggregate allows providing guaranteed entry of core, debris of the internals and the head of the reactor pressure vessel into the corium trap by excluding melt-through of the walls of conical and cylindrical parts and by redistributing the corium jet streams.

The invention relates to the field of nuclear energy, in particular, to systems that ensure the safety of nuclear power plants (NPP), and can be used in severe accidents that lead to reactor pressure vessel and its containment destruction.

The technical result of the claimed invention consists in increasing the reliability of the corium localizing and cooling system of a nuclear reactor, increase of heat removal efficiency from corium of a nuclear reactor.

The technical result is achieved by using the membraned, drum and thermal protection installed in the area between the layered vessel and cantilever truss in the corium localizing and cooling system of a nuclear reactor.

The invention relates to nuclear power engineering and is designed to improve the safety of nuclear power plants by providing the ability to retain the melt in the nuclear reactor vessel at different severity of accidents in both passive and active mode.

In-vessel melt retention system containing a reactor located in a cavity, a coolant circulation pump outside the reactor vessel and a storage tank, characterized in that the storage tank is located in the cavity under the reactor vessel head; there are additional sump tanks above the reactor vessel head to collect coolant in LOCAs, the storage tank is connected to the top of the sump tanks by coolant supply channels.

The in-vessel melt retention system can be applied in nuclear power plants of various types, and can increase their safety by providing melt retention in the reactor vessel in various types of accidents.

A sacrificial concrete for a core catcher and a preparation method thereof are provided. The sacrificial concrete includes raw materials in parts by weight as follows: cement, 575˜625 parts; a quartz sand, 1200˜1300 parts; a hematite ore, 700˜800 parts; water, 200˜220 parts; a water reducing agent, 7˜10 parts; and strontium oxide, 0˜10 parts. The process of the preparation method is simple, and the sacrificial concrete with excellent performances of fluidity, strength and high-temperature resistance can be prepared by the known mixing technology. The sacrificial concrete can reduce releasing of radioactive substances .sup.89Sr and .sup.90Sr, so as to improve safety of nuclear power plants in case of a severe accident. Moreover, the sacrificial concrete can be used not only in a core catcher of current third generation nuclear power plant, but also in a core catcher of future fourth generation nuclear power plant, and has widespread engineering application value.

A sacrificial concrete for a core catcher and a preparation method thereof are provided. The sacrificial concrete includes raw materials in parts by weight as follows: cement, 575˜625 parts; a quartz sand, 1200˜1300 parts; a hematite ore, 700˜800 parts; water, 200˜220 parts; a water reducing agent, 7˜10 parts; and strontium oxide, 0˜10 parts. The process of the preparation method is simple, and the sacrificial concrete with excellent performances of fluidity, strength and high-temperature resistance can be prepared by the known mixing technology. The sacrificial concrete can reduce releasing of radioactive substances .sup.89Sr and .sup.90Sr, so as to improve safety of nuclear power plants in case of a severe accident. Moreover, the sacrificial concrete can be used not only in a core catcher of current third generation nuclear power plant, but also in a core catcher of future fourth generation nuclear power plant, and has widespread engineering application value.

This invention involves systems which provide for the safety of nuclear power plants that can be used in the event of serious accidents leading to the destruction of the housing and sealed containment structure of a reactor. In one aspect, the system can increase nuclear power plant safety by preventing the escape of liquid and solid radioactive materials (corium) from a melt confinement device in the event of a serious accident involving the escape of core melt from a nuclear reactor. The invention addresses the problem of increasing the efficiency and reliability of a melt confinement device by improving the conditions for cooling corium. The problem is solved by the use of a filler formed in upper cassettes and in a lower cassette. Said cassettes are configured with vertical and horizontal channels which provide for the uniform distribution of melt in the housing undergoing cooling.

This invention involves systems which provide for the safety of nuclear power plants that can be used in the event of serious accidents leading to the destruction of the housing and sealed containment structure of a reactor. In one aspect, the system can increase nuclear power plant safety by preventing the escape of liquid and solid radioactive materials (corium) from a melt confinement device in the event of a serious accident involving the escape of core melt from a nuclear reactor. The invention addresses the problem of increasing the efficiency and reliability of a melt confinement device by improving the conditions for cooling corium. The problem is solved by the use of a filler formed in upper cassettes and in a lower cassette. Said cassettes are configured with vertical and horizontal channels which provide for the uniform distribution of melt in the housing undergoing cooling.