US-20260128184-A1 - Molten Salt Nuclear Reactor Core and System

US20260128184A1US 20260128184 A1US20260128184 A1US 20260128184A1US-20260128184-A1

Abstract

A nuclear reactor core ( 1 ) for a molten salt nuclear reactor ( 100 ). The nuclear reactor core ( 1 ) has a tubular cylindrical center moderator vessel ( 10 ) for passage of a liquid moderator ( 11 ), a cylindrical fuel salt jacket surrounding the center moderator vessel ( 10 ), and a cylindrical neutron reflector jacket surrounding the cylindrical fuel salt jacket, wherein the cylindrical center moderator and neutron reflector vessel ( 10 ) has a largest inner cross-sectional area medially between a liquid moderator and neutron reflector inlet ( 12 ) of the center moderator and neutron reflector vessel ( 10 ) and a liquid moderator and neutron reflector outlet ( 13 ) of the moderator and neutron reflector vessel ( 10 ).

Inventors

ASLAK STUBSGAARD
Thomas Jam PEDERSEN

Assignees

COPENHAGEN ATOMICS A/S

Dates

Publication Date: 20260507
Application Date: 20260105
Priority Date: 20210531

Claims (20)

1 . A nuclear reactor system comprising: a molten salt reactor core comprising: a first tubular vessel having an inlet at an inlet end of the vessel, and an outlet at an outlet end of the vessel, said first tubular vessel having an outer wall with a bulbous outer contour, with an outer diameter that tapers from a first midpoint diameter between an inlet end and an outlet end of the first tubular vessel to a second smaller diameter at the inlet end and a third smaller diameter at the outlet end of the first tubular vessel; and a fuel salt jacket disposed about the first tubular vessel, said fuel salt jacket having a second inlet end and a second outlet end, said fuel salt jacket having an inner wall having a contour corresponding to the bulbous outer contour of the outer wall of the first tubular vessel; said fuel salt jacket having an outer wall with a bulbous outer contour with an outer diameter that tapers from a second midpoint diameter of the fuel salt jacket between the second inlet end and the second outlet end of the fuel salt jacket to a second smaller diameter at the second inlet end and a third smaller diameter at the second outlet end of the fuel salt jacket; and a moderator jacket disposed about the fuel salt jacket, said moderator jacket having a third inlet end and a third outlet end, said moderator jacket having an inner wall having a contour corresponding to the bulbous outer contour of the outer wall of the fuel salt jacket; said moderator jacket having an outer wall with a bulbous outer contour with an outer diameter that tapers from a second midpoint diameter of the moderator jacket between the third inlet end and the third outlet end of the moderator jacket to a second smaller diameter at the third inlet end and a third smaller diameter at the third outlet end of the moderator jacket.
2 . The nuclear reactor system of claim 1 , further comprising: a blanket salt jacket disposed about the moderator jacket, said blanket salt jacket having a fourth inlet end and a fourth outlet end, said blanket salt jacket having an inner wall having a contour corresponding to the bulbous outer contour of the outer wall of the moderator jacket.
3 . The nuclear reactor system of claim 1 , further comprising: a first insulation jacket disposed between the first tubular vessel and the fuel salt jacket; and a second insulation jacket disposed between the fuel salt jacket and the moderator jacket.
4 . The nuclear reactor system of claim 1 , further comprising: a first coolant loop and a first heat exchanger, said first coolant loop configured for circulation of fuel salt from the second outlet end of the fuel salt jacket to the first heat exchanger, and thence from the first heat exchanger to the second inlet end of the fuel salt jacket; a first pump in fluid communication with the first coolant loop, said first pump operable to force flow of fuel salt through the first coolant loop, the first heat exchanger, and the fuel salt jacket.
5 . The nuclear reactor system of claim 4 , further comprising: a primary coolant loop and a second heat exchanger, said primary coolant loop configured for circulation of a primary coolant from the first heat exchanger to the second heat exchanger and thence from the second heat exchanger to the first heat exchanger; a second pump in fluid communication with the primary coolant loop, said second pump operable to force flow of primary coolant through the primary coolant loop, the second heat exchanger, and the first heat exchanger.
6 . The nuclear reactor system of claim 5 , further comprising: a secondary coolant loop, said secondary coolant loop configured for circulation of a secondary coolant from the second heat exchanger and return of secondary coolant to the second heat exchanger; and a third pump in fluid communication with the secondary coolant loop, said third pump operable to force flow of secondary coolant through the secondary coolant loop and the second heat exchanger.
7 . The nuclear reactor system of claim 1 , wherein: the fuel salt jacket comprises a plurality of tubular fuel salt vessels extending axially from the second inlet end to the second outlet end, said plurality of tubular fuel salt vessels assembled around the first tubular vessel to form the fuel salt jacket.
8 . The nuclear reactor system of claim 7 , wherein: each of the plurality of tubular fuel salt vessels has an arcuate transverse cross section.
9 . The nuclear reactor system of claim 1 , wherein: the moderator jacket comprises a plurality of tubular moderator vessels extending axially from the third inlet end to the third outlet end, said plurality of tubular moderator vessels assembled around the fuel salt jacket to form the moderator jacket.
10 . The nuclear reactor system of claim 9 , wherein: each of the plurality of tubular moderator vessels has an arcuate transverse cross section.
11 . The nuclear reactor system of claim 1 , wherein: the first tubular vessel contains a liquid moderator and neutron reflector; the fuel salt jacket contains molten fuel salt; and the moderator jacket contains a liquid moderator and neutron reflector.
12 . A nuclear reactor core ( 1 ) for a molten salt nuclear reactor ( 100 ), said nuclear reactor core ( 1 ) comprising: a first tubular vessel ( 10 ) having a first inlet ( 12 ) and a first outlet ( 13 ) and a first passage communicating from said first inlet to said first outlet, said first tubular vessel characterized by a first axis extending from said first inlet ( 12 ) to said first outlet ( 13 ); a plurality of second tubular vessels ( 20 ), each of the plurality of second tubular vessels ( 20 ) having a second inlet ( 22 ) and a second outlet ( 23 ) and a second passage communicating from said second inlet to said second outlet; a plurality of third tubular vessels ( 30 ), each of the plurality of third tubular vessels ( 30 ), having a third inlet ( 32 ) and a third outlet ( 33 ) and a third passage communicating from said third inlet to said third outlet ( 33 ) ; wherein said plurality of second tubular vessels ( 20 ) are assembled to form a first jacket surrounding said first tubular vessel ( 10 ); said plurality of third tubular vessels ( 30 ) are assembled to form a second jacket surrounding said first jacket; and the first tubular vessel ( 10 ) has a fusiform shape.
13 . The reactor core of claim 12 , wherein: the first jacket has an inner wall having a contour corresponding to the fusiform outer contour of the first tubular vessel, and the first jacket has a fusiform outer contour; and the second jacket has an inner wall having a contour corresponding to the fusiform outer contour of the first jacket, and the second jacket has fusiform outer contour.
14 . The reactor core of claim 13 , further comprising: a third jacket disposed about the second jacket, said third jacket having an inner wall having a contour corresponding to the fusiform outer contour of the second jacket.
15 . The nuclear reactor core of claim 12 , further comprising: a first insulation jacket disposed between the first tubular vessel and the first jacket; and a second insulation jacket disposed between the first jacket and the second jacket.
16 . The nuclear reactor core of claim 12 , further comprising: a first coolant loop and a first heat exchanger, said first coolant loop configured for circulation of fuel salt from the first jacket to the first heat exchanger, and thence from the first heat exchanger to the first jacket; a first pump in fluid communication with the first coolant loop, said first pump operable to force flow of fuel salt through the first coolant loop, the first heat exchanger, and the first jacket.
17 . The nuclear reactor core of claim 16 , further comprising: a primary coolant loop and a second heat exchanger, said primary coolant loop configured for circulation of a primary coolant from the first heat exchanger to the second heat exchanger and thence from the second heat exchanger to the first heat exchanger; a second pump in fluid communication with the primary coolant loop, said second pump operable to force flow of primary coolant through the primary coolant loop, the second heat exchanger, and the first heat exchanger.
18 . The nuclear reactor core of claim 12 , further comprising: a secondary coolant loop, said secondary coolant loop configured for circulation of a secondary coolant from the second heat exchanger and return of secondary coolant to the second heat exchanger; and a third pump in fluid communication with the secondary coolant loop, said third pump operable to force flow of secondary coolant through the secondary coolant loop and the second heat exchanger.
19 . The nuclear reactor core of claim 12 , wherein: each of the plurality of second tubular vessels has an arcuate transverse cross section.
20 . The nuclear reactor core of claim 12 , wherein: each of the plurality of third tubular vessels has an arcuate transverse cross section.

Description

This application is a continuation of U.S. application Ser. No. 18/564,489, filed Nov. 27, 2023, which is a national stage of International Application PCT/DK 2022/050109, filed May 25, 2022, which claims priority to Danish applications PA202l 70280, PA202l 70281 and PA202l 70282, each filed on May 31, 2021. TECHNICAL FIELD The disclosure relates to a molten salt nuclear reactor core and method of operating such nuclear reactor core, in particular to the construction and design of the nuclear reactor core of a molten salt nuclear reactor and method of operating such nuclear reactor core. BACKGROUND A molten salt reactor (MSR) is a nuclear reactor where the nuclear reactor coolant and/or the nuclear fuel is a molten salt, typically a fluoride or chloride salt, with a melting point of around ˜500° C., operating temperature of around ˜600 to 700° C., and a boiling point of ˜1000° C. above the melting point. One of the many advantages of this type of reactor is that molten salts can be used as the heat transfer media at very high temperatures while still operating at or close to atmospheric pressure. Heat can be extracted from such reactors by pumping the molten salt in a loop between the nuclear reactor core and a heat exchanger with the reactor power being directly proportional to the temperature drop across the heat exchanger and the flow rate. Due to the corrosive nature of molten fluoride and chloride salt, their operation requires an inert containment atmosphere, furthermore molten salt or molten salt vapors cannot be allowed to escape to the environment, putting strict requirements on molten salt reactor components to be completely leak tight. This poses a severe technical challenge, since the temperature and the aggressive nature of the molten salt combined with high radiation levels renders only very few suitable materials to work with. Thus, the materials that can be used to construct the core have to be carefully selected and combined in order to obtain a solution that provides a reliable and durable nuclear reactor core. Molten salt reactors were built and operated at Oak Ridge National Laboratory (ORNL) in the 1950s and 1960s with a research program lasting to the 1970s and other small programs around the world. The nuclear reactor core has a special geometry designed to allow a nuclear chain reaction to take place, achieved by either 1. a large enough amount of fuel to make a critical assembly or by2. combining enough moderator and fuel to make a critical assembly. These are respectively called fast and thermal reactors because of the resulting neutron spectrum that each type exhibits. There is a need for compact and mass manufacturable molten salt breeder reactors in order to achieve the goal of meeting the future global energy demand in a sustainable fashion. This creates a significant challenge since the smaller one makes a reactor the harder it becomes for it to achieve breeding, since the probability of neutrons leaving the reactor, referred to as neutron leakage, roughly increases with the larger surface area to volume ratio of a small reactor. Fast reactors generally require a much larger fissile inventory to become critical when compared to thermal reactors and are thus not well suited to scale up rapidly to meet future energy demand because of limited availability of fissile material. Thus, a compact and mass manufacturable thermal molten salt breeder reactor is desired. One of the challenges for thermal molten salt breeder reactors is the need for a moderator that effectively slows down neutrons while allowing for breeding, which means that only moderators based on carbon, beryllium, or deuterium can be used. The only practical moderators that will allow breeding in a thermal spectrum molten salt reactor are: solid carbon, solid beryllium, molten enriched lithium 7 deuteroxide salt (7LiOD), or liquid heavy water (D20). Of these, carbon is the only one that can withstand direct contact with the fuel salt, while the others need to have a structural material separating them from the fuel salt. All these moderators have their pros and cons and have been proposed and studied in the past for use as moderators in a molten salt reactor. Another challenge is the choice of materials for the vessels that contain the fuel salt or moderator material if the moderator is separated from the fuel salt. The materials need to resist degradation under extremely high temperatures, intense radiation exposure, and must have suitable neutron absorption properties as well as resistance to the corrosive effect of molten salt for the vessels containing molten salt. Various materials have been proposed and studied in the past for use in the construction of the components of a molten salt reactor. However, each of these materials has practical limitations in relation to the shapes that are possible to produce in commercial manufacturing. The only known molten salt compatible materials with low neutron absorption ar