Small Modular Nuclear Reactor

Small Modular Nuclear Reactor

Acad. Oleg Figovsky

As nuclear power generation has become established since the 1950s, the size of reactor units has grown from 60 MWe to more than 1600 MWe, with corresponding economies of scale in operation. At the same time there have been many hundreds of smaller power reactors built for naval use (up to 190 MW thermal) and as neutron sources, yielding enormous expertise in the engineering of small power units and accumulating over 12000 reactor years of experience. The International Atomic Energy Agency (IAEA) defines «small» as under 300 MWe, and up to about 700 MWe as «medium» – including many operational units from the 20th century. Together they have been referred to by the IAEA as small and medium reactors (SMRs). However, «SMR» is used more commonly as an acronym for «small modular reactor», designed for serial construction and collectively to comprise a large nuclear power plant. (In this information page the use of diverse pre-fabricated modules to expedite the construction of a single large reactor is not relevant.) A subcategory of very small reactors – vSMRs – is proposed for units under about 15 MWe, especially for remote communities.

Small modular reactors (SMRs) are defined as nuclear reactors generally 300 MWe equivalent or less, designed with modular technology using module factory fabrication, pursuing economies of series production and short construction times. This definition, from the World Nuclear Association, is closely based on those from the IAEA and the US Nuclear Energy Institute. Some of the already-operating small reactors mentioned or tabulated below do not fit this definition, but most of those described do fit it. PWR types may have integral steam generators, in which case the reactor pressure vessel needs to be larger, limiting portability from factory to site. Hence many larger PWRs such as the Rolls-Royce UK SMR have external steam generators.

US4508677(A) - Modular nuclear reactor for a land-based power plant and method for the fabrication, installation and operation thereof.

A self-contained modular nuclear reactor which can be prefabricated at a factory location, nuclear-certified at the factory, transported to a field location for final assembly and connection to a large-scale electric-power generating facility. The modular reactor includes a prefabricated nuclear heat supply module and a plurality of shell segments which can be assembled about the heat supply module and which provide a form for the pouring and curing of a cementatious biological shield about the heat supply module. The modular reactor includes passive shutdown heat removal systems sufficient to render the reactor safe in an emergency. A large-scale power plant arrangement is disclosed which incorporates a plurality of the modular reactors. Below your could see a few of patents on Small Modular Nuclear Reactors

KR20250070170 (A) - Heating system for small modular nuclear reactors and a heating method using the same.

The present invention relates to a temperature raising system for a small modular nuclear power plant, comprising: a nuclear reactor assembly unit including a plurality of integrated nuclear reactors; a turbine unit which operates through steam supplied from an operating nuclear reactor being in operation in the reactor assembly unit; and a steam storage unit in which at least part of the steam supplied to the turbine unit is extracted and stored, and which supplies the steam to a starter nuclear reactor requiring to be started in the nuclear reactor assembly unit.

KR20250088180 (A) - Comprehensive safety and accident management autonomous driving platform for nuclear power plants using artificial intelligence machine learning technology and big data and a safe autonomous driving platform for small modular and micro-reactors.

The present invention relates to a comprehensive safety and accident management platform for operating nuclear power plants to improve safety and operational efficiency by supporting operators by utilizing big data on operation, safety, and accidents of operating nuclear power plants, which are constructed by analyzing artificial intelligence machine learning technology, real-time measurement signals, and optimal safety analysis codes, and to a digital twin virtual reactor platform for autonomous operation of small and medium modular and micro-reactors being developed internationally for various purposes such as oceans, space, and hostile sites, comprising: a plant simulation module that generates plant monitoring data of a nuclear power plant; a data anomaly detection module that verifies whether the transmitted plant monitoring data is data used for training or data not yet used. It includes an accident diagnosis module and an accident prediction module that diagnose and predict abnormal conditions of a power plant in advance through a neural network that has learned the state of the power plant in advance, including normal and accident states, by inputting time series data of variables used in the plant simulation module including normal and accident states by inputting input plant monitoring data, and an action output module that performs a preset response according to the diagnosed state, and it is a comprehensive safety and accident management automatic operation platform for supporting operators of operating nuclear power plants that can prevent accidents and incidents by predicting accidents and incidents in advance and mitigate the impact of accidents and incidents in the event of accidents, and a safe autonomous operation platform for small and medium modular and micro nuclear reactors.

SI3058232 (T1) - Motor-driven centrifugal pump for the primary circuit of small or medium-sized modular nuclear reactors.

The invention relates to a motor-driven centrifugal pump for circulation of heat transfer fluid in the primary circuit of a nuclear reactor. The motor-driven pump comprises a hermetic motor unit, a hydraulic section and a shaft immersed in the heat transfer fluid, rotated by the hermetic motor unit and pumping the heat transfer fluid by means of an impeller of the hydraulic section rigidly connected to the shaft. The motor unit comprises a dry stator and an immersed rotor, rigidly connected to the shaft. The motor-driven pump also comprises an immersed flywheel rigidly connected to the shaft between the rotor of the motor unit and the impeller of the hydraulic section, enabling a minimum slowing down time after cutting of the electrical power supply; and an immersed device for preventing rotation in the wrong direction, configured so as to mechanically block rotation of the shaft in a predetermined direction.

KR20250076107 (A) - SMR apparatus for transferring nuclear fuel assemblies within a nuclear power plant including small modular reactors smr and method using the same.

The present invention relates to an apparatus for transporting a nuclear fuel assembly, the apparatus, which transports a nuclear fuel assembly within a nuclear power plant comprising small modular reactors (SMRs), comprising: a hoist box that can move within the nuclear power plant, moving between the SMRs and nuclear fuel assembly; a fixing part partially attached to the nuclear fuel assembly to fix same; first and second wires connecting the hoist box and fixing part, the first wire supporting the fixing part during the lowering stage; a stiffness adjustment part for adjusting the stiffness of the second wire.

SI3058231 (T1) - Motor-driven centrifugal pump for the primary circuit of small or medium-sized modular nuclear reactor.

The invention relates to a motor-driven centrifugal pump for circulation of heat transfer fluid in the primary circuit of a nuclear reactor. The motor-driven pump comprises a hermetic motor unit, a hydraulic section and a shaft immersed in the heat transfer fluid, rotated by the hermetic motor unit, and pumping the heat transfer fluid by means of an impeller of the hydraulic section that is rigidly connected to the shaft; the motor unit comprising a dry stator and an immersed rotor rigidly connected to the shaft. The motor-driven pump also comprises an immersed flywheel rigidly mounted on the shaft between the rotor of the motor unit and the impeller of the hydraulic section, enabling a minimum slowing-down time after cutting of the electrical power supply; the flywheel comprising a vane wheel generating circulation of the heat transfer fluid for cooling the motor unit.

NANO Nuclear Energy Inc. (NASDAQ: NNE) («NANO Nuclear» or «the Company»), a leading advanced nuclear energy and technology company focused on developing clean energy solutions, today announced that it has closed its previously announced acquisition of select nuclear energy technology assets, including the patented Micro Modular Reactor (MMR®) Energy System and Pylon Transportable Reactor Platform, from Ultra Safe Nuclear Corporation and certain of its subsidiaries (collectively, «USNC»).

The acquisition of these assets and related intellectual property and contracts significantly expands NANO Nuclear’s patent portfolio and adds to its existing pipeline of cutting edge small nuclear reactor technologies in development. The assets include 38 issued and pending or published patents, including six issued and four pending or published U.S. utility patents and three issued and four pending Canadian utility patents, as well as associated trademarks.

The acquisition also brings important demonstration project collaborations related to the MMR^® system, notably at the University of Illinois at Urbana-Champaign. Pending Canadian governmental approvals, the acquisition would also bring certain Canadian government relationships and support. Further, certain of the technology acquired by NANO Nuclear in this acquisition was being used by an affiliate of USNC to develop related technology in the United Kingdom, and NANO Nuclear may be able to explore a potential future license or acquisition of such related technology in the United Kingdom, which could be accompanied by U.K. government support.