Modular Reactor Steam Generator Surrounding Vessel
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Solution Overview
Problem
Small-medium modular reactors face challenges with complex structures, limited spatial efficiency, and maintenance difficulties due to integrated steam generators and pipes, which complicate heat transfer, pressure boundary maintenance, and pipe break risks.
Innovation Solution
An externally integrated once-through steam generator type small modular reactor design where a steam generator surrounds the reactor vessel, eliminating the need for pipes by using penetration holes for fluid flow, simplifying the structure, and increasing spatial efficiency, with a concentric arrangement that allows for easier maintenance and reduced pipe break risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the steam generator is installed inside the reactor vessel, then the structure is compact and integrated, but the pressure boundary becomes complex and maintenance access is limited
Solution Approach 1:
The steam generator is nested within the reactor vessel, with the steam generator shell positioned inside the reactor vessel. The primary cooling water flow path is defined between the steam generator shell and the reactor vessel inner wall, creating a nested configuration that achieves compact integration while maintaining distinct pressure boundaries through the steam generator shell and associated seals.
Solution Approach 2:
The reactor vessel is segmented into distinct functional regions: the core region, the steam generator region, and the annular primary cooling water flow path between them. This segmentation allows separate access and maintenance of different components while maintaining overall integration, with penetration holes providing access points in the steam generator shell for maintenance activities.
2Reliability
If pipes are used to connect components, then fluid flow between components is enabled, but pipe break risks and maintenance difficulties increase
Solution Approach 1:
The steam generator shell serves multiple functions simultaneously: it acts as the steam generator containment, defines the primary cooling water flow path boundary, and provides structural integration with the reactor vessel. This merging eliminates the need for separate pipes to connect the steam generator to the reactor vessel, as fluid flow is achieved through the annular space between the steam generator shell and reactor vessel inner wall.
3Productivity
If the steam generator heat transfer area is increased, then steam generation efficiency improves, but the reactor vessel volume requirement increases
Solution Approach 1:
The heat transfer surface is extended into the radial dimension by forming heat transfer tubes that protrude from the steam generator shell into the annular primary cooling water flow path. This dimensional extension increases the heat transfer area without significantly increasing the overall reactor vessel volume, as the heat transfer occurs in the radial space between the steam generator shell and reactor vessel inner wall.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enhances heat transfer area, simplifies the reactor structure, reduces maintenance complexity, and eliminates pipe break risks, enabling efficient generation of superheated steam and flexible design modifications while minimizing environmental qualification requirements.
Implementation Method 1
generating superheated steam from secondary cooling water flowing in heat transfer tubes
Data Source
AI summary
In an externally integrated once-through steam generator type small modular reactor, a steam generator is arranged along the circumference of a reactor vessel, and secondary cooling water flows in heat transfer tubes and changes to superheated steam. The small modular reactor includes: a nuclear reactor including a hemispherical upper head, the reactor vessel cylindrical shell coupled to the upper head and extending downward from the upper head in a cylindrical shape, and a hemispherical lower head provided on a lower portion of the reactor vessel cylindrical shell, wherein a core is placed in the nuclear reactor; the steam generator surrounding all around the reactor vessel cylindrical shell, the steam generator including a first penetration hole communicating with an inside of the nuclear reactor and a second penetration hole separate from the first penetration hole and communicating with the inside of the nuclear reactor.