Radioisotope recovery system

Abstract

The invention relates to the design, configuration and operation concept of a system, herein called radioisotope recovery system, to deploy and recover different precursor materials into and from the core of a nuclear fusion tokamak with beam-driven plasma for the purpose of exposing these materials to the neutron flux generated in the plasma by the process of nuclear fusion of D and T ions, which will cause the generation of radioactive isotopes (also called radioisotopes). Main characteristics of the invention are (i) a closed loop that circulates precursor materials into and out of a nuclear fusion tokamak with beam-driven plasma, (ii) the compliance of the system with the design and maintenance of a nuclear fusion tokamak with beam-driven plasma.

Description

[0001] Radioisotope recovery system

[0002] Technical field:

[0003] The present invention relates to the field of Physics - Nucleonics - fusion reactors - thermonuclear fusion reactors - with magnetic or electric plasma confinement - tokamaks (G21B 1 / 057). It specifically relates to the design, configuration and operation concept of a system to deploy and recover different precursor materials into and from the core of a fusion tokamak with beam-driven plasma for the purpose of exposing these materials to the neutron flux generated in the plasma by the process of nuclear fusion of D and T ions, for the purpose of generating radioactive isotopes, as described in PCT / EP2024 / 076727 - “Radioisotope production in a nuclear fusion tokamak” filed on 24.09.2024.

[0004] Background of the invention:

[0005] The production of radioisotopes requires the exposure of precursor materials to neutrons. The plasma in a nuclear fusion device is an intense neutron source if operated with Deuterium, D, and Tritium, T. The principal possibility to produce radioisotopes in a nuclear fusion device is presented in [2], The authors of [2] consider, in contrast to this invention, a large fusion device called DEMO where the very high temperature in the plasma causes the fusion of D and T ions. Since most of the inner wall of DEMO that is exposed to neutrons must be used to breed DEMO's tritium fuel, the authors of [2] consider for the deployment of the precursor materials, in contrast to this invention, a port plug (13) with a comparably small surface exposed to the neutron flux. Furthermore, in contrast to this invention, the authors of [2] consider for the deployment and recovery of the precursor materials irradiation rods resembling the fuel rods of fission reactors.

[0006] Description:

[0007] The invention relates to the design, configuration and operation concept of a system, herein called radioisotope recovery system, to deploy and recover different precursor materials into and from the core of a nuclear fusion tokamak with beam-driven plasma for the purpose of exposing these materials to the neutron flux generated in the plasma by the process of nuclear fusion of D and T ions, which will cause the generation of radioactive isotopes (also called radioisotopes), as described in PCT / EP2024 / 076727 - “Radioisotope production in a nuclear fusion tokamak” filed on 24.09.2024.

[0008] In a nuclear fusion tokamak with beam-driven plasma as considered in PCT / EP2024 / 076727 - “Radioisotope production in a nuclear fusion tokamak” filed on 24.09.2024 it is foreseen to integrate fusion nuclear components for the purpose of testing and qualification on the outboard side (8) of the torus-shaped plasma vessel (6). On the inboard side (9) instead a blanket (10) with neutron absorbing materials (17) is integrated due to design constraints of such tokamaks. This invention adds to the previous invention as described in PCT / EP2024 / 076727 a system that deploys and recovers precursor materials in the inboard blankets (10) without compromising their neutron absorbing function. As an option, this invention could be implemented also to some of the outboard blankets.

[0009] The radioisotope recovery system is the closed loop of a pressurized liquid media (24), e.g. water, that consists of auxiliary components operating the loop such as the pump (20) and other auxiliary systems, of a pipe (14), and of metallic capsules (23) floating in the liquid media inside the pipe. The shape of the capsules is spherical or cylindrical with rounded corners to prevent jamming of the capsules inside the loop. The pipe connects the auxiliary components to the blanket (10) and is welded to an extension pipe (15) that is integrated into the blanket in multiple bends (22) behind the blanket first wall (16) where the neutron flux is intensive. The auxiliary components of the loop are located outside the bioshield (4) of the nuclear fusion tokamak with beam-driven plasma in areas protected from excessive neutron and gamma radiation and accessible by remote controlled tools or personnel. The auxiliary components include a system to recover the metallic capsules from the loop (19) upon completion of an irradiation period, a system to refill new metallic capsules into the loop (18) with new precursor materials (25), a low flow pump (20), valves (21) and other parts. These auxiliary components are operated semi-automatically through tools that are controlled by an operator (11) located in a control room (12) outside the reactor building (1).

[0010] The transfer of the metallic capsules (23) between the port cell (2) and the active maintenance facility is carried out making use of the transfer system and related installations for the remote replacement of the blankets implemented in the reactor building and adjacent buildings of the plant. The metallic capsules are transported to and picked up from the port cell (2) by a remotely controlled vehicle that can enter and exit into the port cell through a rotating door (3) with sealing function.

[0011] The preparation of the metallic capsules (23) with precursor materials (25) and their recovery after irradiation is carried out in the active maintenance facility, which may be in a separate building adjacent to the reactor building or within the reactor building.

[0012] The liquid media (24) inside the closed loop is continuously flown through the operation of the low flow pump (20). This causes the metallic capsules (23) to continuously circulate through the loop. In different parts of the loop, they are exposed to different levels of neutron flux. Over the time of the irradiation period, however, a uniform irradiation of the precursor materials (25) in the different capsules is obtained.

[0013] Due to the continuous circulation of the metallic capsules (25) in the loop during the irradiation period, they are naturally extracted from the reactor core and transported outside of the bioshield (4). Their recovery from the loop is possible within hours after the completion of the irradiation period because neither the plasma vessel (6) nor the bioshield (4) must be opened for access. Consequently, this invention allows the production also of radioisotopes with short half-lives of the order of hours or days, which would naturally decay if the recovery from the capsules took too long, e.g. several days.

[0014] A nuclear fusion tokamak with beam-driven plasma is built of several, e.g. 12, sectors forming the 360° torus. In each sector there are two inboard blankets (10). Therefore, several, e.g. 24, radioisotope recovery systems can be installed that can operate independently and with operating parameters customized to the neutron exposure requirements of different precursor materials (25).

[0015] The configuration and integration of the loop's pipe (14) connecting the blanket (10) with the auxiliary components penetrates the wall of the upper port (5) rather than the removable port closure plate (7) and therefore is compliant with the upper port remote handling concept described in [3], i.e. with the maintenance concept of the blanket.

[0016] References:

[0017] [1] Federici, Gianfranco. "Testing needs for the development and qualification of a breeding blanket for DEMO." Nuclear Fusion 63.12 (2023): 125002. doi: 10.1088 / 1741-4326 / ad00cb

[0018] [2] Pereslavtsev, P.; Bachmann, C.; Elbez-Uzan, J.; Park, J.H. Potential of Radioactive Isotopes Production in DEMO for Commercial Use. Appl. Sci. 2024, 14, 442. https: / / doi.org / 10.3390 / app14010442

[0019] [3] Mozzillo, Rocco, et al. "Replacement strategy of the EU-DEMO and CFETR breeding blanket pipes." Fusion Engineering and Design 202 (2024): 114311. https: / / doi.Org / 10.1016 / j.fusengdes.2O24.114311 Brief description of the drawings:

[0020] Figure 1 is a vertical cross-section through the reactor building (1) of the nuclear fusion tokamak with beam-driven plasma including main systems relevant to this invention, most other reactor systems are not shown.

[0021] Figure 2 is an isometric view of the configuration of the radioisotope recovery system showing the arrangement with other reactor systems and relevant interfaces.

[0022] Figure 3 is a section of the pipe (14) with metallic capsules (23).

[0023] Figure 4 is a metallic capsule (23) shown here exemplary with a spherical shape, cut in half, containing a specimen of a precursor material (25).

[0024] Reference signs:

[0025] (1) Reactor building

[0026] (2) Port cell

[0027] (3) Rotating door

[0028] (4) Bioshield

[0029] (5) Upper port

[0030] (6) Plasma vessel

[0031] (7) Closure plate

[0032] (8) Outboard side

[0033] (9) Inboard side

[0034] (10) Inboard blanket

[0035] (11) Operator

[0036] (12) Control room

[0037] (13) Port plug

[0038] (14) Pipe

[0039] (15) Extension pipe

[0040] (16) First wall

[0041] (17) Neutron absorbing materials

[0042] (18) Capsule refill system

[0043] (19) Capsule recovery system

[0044] (20) Pump

[0045] (21) Valves

[0046] (22) Bend

[0047] (23) Metallic capsule

[0048] (24) Liquid media

[0049] (25) Precursor material

Claims

Claims:1 . A remotely operated system to deploy and recover different materials into and from the core of a nuclear fusion tokamak with beam-driven plasma, herein called radioisotope recovery system, for the purpose of exposing these materials to neutrons, which will cause the generation of radioactive isotopes (also called radioisotopes), comprising:• A loop with pressurized liquid (24) e.g., water, made of stainless-steel pipes (14), (15) with constant inner diameter (approximately 10 mm).• Metallic stainless-steel capsules (approximately 10,000 with external diameter somewhat smaller than the inner diameter of the pipe) stacked up inside the pipes of the loop.• A remotely operated low-flow pump (20).• A remotely operated system to fill metallic capsules into the pipe (18).• A remotely operated system to recover the metallic capsules from the pipe (19). characterized in that• All components operating the loop i.e. , pump (20), capsule recovery (19) and refill (18) systems, valves, are located outside the bioshield (4), and therefore are located in areas (i) accessible by remote controlled tools or personnel, (ii) protected from excessive neutron and gamma radiation.• The continuous operation of the loop i.e. circulation of the liquid (24) with metallic capsules (23) means each capsule passes multiple times through the blanket ensuring a homogeneous exposure to neutrons amongst all capsules of one loop.• The system operation mode i.e., flow velocity and time to recover the metallic capsules, can be customized to the production of radioisotopes from different precursor materials (25).

2. The radioisotope recovery system according to Claim 1 , characterized in that the pressurized liquid loop transports the metallic capsules reliably by avoiding blockage due to congestion through the following features: (i) the capsules are made of robust stainless steel, (ii) the external shape of metallic capsules and the internal shape of pipes are without major irregular geometries, (iii), equal or similar density of metallic capsules incl. precursor materials and their container to density of transport liquid, (iv) conventional technologies used for components operating the loop e.g., pump, valves, etc.

3. The radioisotope recovery system according to Claim 1 , characterized in that the precursor materials (25) are contained in metallic capsules (23) that allow their transport in a pipe (14) in a liquid media (24).

4. The radioisotope recovery system according to Claim 1 , characterized in that part of the loop's pipes (15) are integrated into the neutron shielding blanket (10) on the inboard side (9) and optionally also on the outboard side of the nuclear fusion tokamak with beam-driven plasma.

5. The radioisotope recovery system according to Claim 1 , characterized in that the configuration of the loop's pipes that connect the components operating the loop with the blanket inside the primary vessel is compatible with the maintenance of the blanket.

6. The radioisotope recovery system according to Claim 1 , characterized in that the auxiliary components of the loop requiring in-service maintenance and inspection are located outside the bioshield (4) of the nuclear fusion tokamak with beam-driven plasma in areas protected from excessive neutron and gamma radiation and accessible by remote controlled tools or personnel.

7. The radioisotope recovery system according to Claim 1 , characterized in that the continuous circulation of the metallic capsules (23) ensures a uniform exposure to neutron flux amongst the different capsules.

8. The radioisotope recovery system according to Claim 1 , characterized in that the circulation of the metallic capsules (23) ensures the transport of the capsules from the reactor core outside the bioshield (4) allowing for a recovery of the metallic capsules without major intervention and, possibly, not requiring the plasma to be shutdown.

9. The radioisotope recovery system according to Claim 1 , characterized in that the transfer of the metallic capsules (23) between the port cell (2) and the active maintenance facility is carried out making use of the transfer system and related installations implemented in the reactor building and adjacent buildings of the plant for the remote replacement of the blankets.

10. The radioisotope recovery system according to Claim 1 , characterized in that its configuration allows implementing several radioisotope recovery systems in one nuclear fusion tokamak with beam-driven plasma that can be operated simultaneously, independently and with individual operation parameters such as flow velocity or irradiation period.

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