Device for Passive Protection of a Nuclear Reactor

• US 20180174693A1
• Filed: 04/05/2016
• Published: 06/21/2018
• Est. Priority Date: 06/01/2015
• Status: Active Grant

• Current Assignee: State Atomic Energy Corporation Rosatom
• Original Assignee: State Atomic Energy Corporation Rosatom
• Inventors: SLESAREV, Igor Sergeevich, LEONOV, Viktor Nikolaevich, KUBINTSEV, Boris Borisovich, RODINA, Elena Aleksandrovna, CHERNOBROVKIN, Yuriy Vasilevich, SHEVCHENKO, Aleksey Borisovich
• Granted Patent: US 10,643,755 B2
• Time in Patent Office: Days
• CPC Class Codes: G21C 15/18 Emergency cooling arrangements; Removing shut-down heat
• CPC Class Codes: G21C 3/326 comprising fuel elements of different composition; comprising, in addition to the fuel elements, other pin-, rod-, or tube-shaped elements, e.g. control rods, grid support rods, fertile rods, poison rods or dummy rods
• CPC Class Codes: G21C 7/22 by displacement of a fluid or fluent neutron-absorbing material , e.g. by adding neutron-absorbing material to the coolant
• CPC Class Codes: G21C 7/24 Selection of substances for use as neutron-absorbing material
• CPC Class Codes: G21C 9/024 Rupture diaphragms
• CPC Class Codes: G21C 9/033 by an absorbent fluid
• CPC Class Codes: Y02E 30/30 Nuclear fission reactors

Abstract

The invention relates to nuclear reactor protection systems and can be used when building nuclear reactors, in particular, the fast neutron reactors. The Technical result of the invention consists in the expansion of 5 functional capabilities of the negative reactivity passive insertion device by securing its reliable actuation in various emergency conditions. The device has two vessels located in a common enclosure one under another with a ring-shape hollow space between the vessels and the enclosure to let the heat carrier flow. Fuel elements are located in the ring-shape hollow space, as well as the tooling for the heat carrier flow formation to cool the fuel elements and heat the upper vessel. The upper vessel is located above the reactor core and is divided with an internal partition wall to the central cylindrical and ring-shape hollow spaces. The partition wall has low thermal conductivity in the transverse direction. In the central hollow space of the upper vessel the cadmium isotope is mainly located, while in its ring-shape space—mercury. Lower vessel is mainly located in the active core of the reactor and filled with inert gas. The vessels and are connected with a pipe with a partition, made in the form of buckling rapture disc.

Claims

1. The device for the nuclear reactor passive protection is made in the form of two vessels located in the common enclosure one under another with a ring-shape hollow space to allow the heat carrier flow, the upper vessel is located higher than the reactor core and is partially filled with molten metal with large neutron-absorption cross-section, as well with molten metal with high vapour pressure within the range of the probable heat carrier temperatures;

the lower vessel is mainly located in the reactor core and is filled with an inert gas;

the vessels are interconnected with a partitioned pipe 10 made in the form of a buckling rapture disc, at that the fuel assemblies, as well as the means for the heat carrier flow forming to cool down the fuel assemblies and heat the upper vessel are located in the ring-shape hollow space.

2. The device according to claim 1, distinguished by the fact, that the mercury isotope—

¹⁹⁹Hg is used as a molten metal with large neutron-absorption cross-section and a molten metal with high vapour pressure in the range of the possible heat carrier temperatures.

3. The device according to claim 1, distinguished by the fact, that In mercury alloys with cadmium isotopes ^ulCd and/or ¹¹³Cd is used as a molten metal with large neutron-absorption cross-section and a molten metal with high vapour pressure in the range of the possible heat carrier temperatures.

4. The device according to claim 1, distinguished by the fact, that mercury can be used as molten metal with high vapour pressure in the range of the probable heat carrier temperatures, and the cadmium isotopes mCd and/or ¹¹³Cd can be used as the molten metal with large neutron absorption cross-section.

5. The device according to claim 1, is distinguished by the fact, that an internal partition wall is located in the upper vessel to form the interconnected central cylindrical and ring-shape hollow spaces in the upper part, at that the partition wall has low heat conductivity in the transverse direction.

6. The device according to claim 5, distinguished by the fact that the wall 30 of the internal partition is made with two layers with a gas heat-insulating gap between the layers.

7. The device according to claim 5 distinguished by the fact, that in its central hollow space a molten metal with high neutron-absorption cross-section is located, and in the ring-shape upper vessel is mainly located a molten metal with high vapour pressures in the range of the probable heat carrier temperatures.

8. The device according to claim 1, distinguished by the fact, that the tooling of the heat carrier flow formation for the fuel assembly cooling is made as a lower pipe shell located between the lower vessel and the fuel elements, and with a transverse partition wall of the ring-shape hollow space in the upper part.

9. The device according to claim 1, distinguished by the fact, that the tooling of the heat carrier flow formation for the upper vessel heating is made as a lower pipe shell located between the upper vessel and the enclosure, and with a transverse partition wall of the ring-shape hollow space in the peripheral part.

10. The device according to claim 8, distinguished by the fact, that the hollow space between the lower vessel and the lower pipe shell, and the hollow space between the enclosure and the upper pipe shell are interconnected with each other via at least one pipe channel.

11. The device according to claim 1, distinguished by the fact, that in the cross-section the shape and the size of the enclosure mainly match the shape and the size of the reactor fuel assembly.

12. The device according to claim 11, distinguished by the fact that in the transverse cross-section the enclosure is made as a hexagon.

13. The device according to claim 8, distinguished by the fact, that in the cross-section the shape of the pipe shell for forming the heat carrier flow for the fuel element cooling mainly matches the shape of the device enclosure.

14. The device according to claim 9, distinguished by the fact, that in the cross-section the shape of the pipe shell for the upper vessel heating mainly matches the shape of the upper vessel.

15. The device according to claim 1 is distinguished by the fact that pipe elements with neutron moderator, e.g., beryllium oxide, are located between the lower vessel and the heat carrier flow forming device, to cool down the fuel elements.