Integral PWR Upper Internals Segmentation for Compact Vessel Design
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Solution Overview
Problem
Conventional pressurized water reactor (PWR) designs face challenges in compact modular reactor configurations due to the need for substantial vertical space for control rod drive mechanisms and steam generators, which complicates vessel penetration and maintenance access.
Innovation Solution
The design separates the pressure vessel into an upper section with steam generators and a lower section with control rod drive mechanisms, eliminating vertical overlap and allowing the upper vessel to be lifted laterally without clearing the CRDM units, enabling a more compact and modular configuration with reduced weight and improved maintenance access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If control rod drive mechanisms and steam generators are located inside the pressure vessel with vertical overlap, then the reactor configuration is more compact, but the upper vessel height and weight increase, complicating maintenance access and vessel penetration
Solution Approach 1:
The pressure vessel is segmented into an upper section and a lower section, with the CRDM units positioned entirely in the lower section. This segmentation allows the upper vessel height to be reduced while maintaining the compact integral configuration, as the steam generators and CRDM units are vertically separated into distinct sections rather than overlapping
2Ease of repair
If control rod drive mechanisms are positioned entirely within the lower vessel section, then maintenance access and vessel removal are facilitated, but the lower vessel height must be increased
Solution Approach 1:
The CRDM units are positioned in the lower vessel section with their full height accommodated there, eliminating vertical overlap with the upper section. This dimensional arrangement allows the upper vessel to be removed and set aside laterally without needing to clear the CRDM units vertically, significantly improving maintenance access while organizing components by functional zones
3Weight of stationary object
If steam generators and control rod drive mechanisms are vertically overlapped, then weight distribution is optimized, but operational complexity increases during refueling and inspection
Solution Approach 1:
The reactor internals are segmented into functionally distinct zones: the lower vessel section contains the CRDM units and reactor core, while the upper vessel section contains the steam generators. This spatial segmentation eliminates operational complexity during refueling and inspection, as the upper vessel can be independently removed without interfering with the CRDM units, allowing straightforward access to the core
Data Source
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AI summary
An integral pressurized water reactor (PWR) comprises: a cylindrical pressure vessel including an upper vessel section and a lower vessel section joined by a mid-flange; a cylindrical central riser disposed concentrically inside the cylindrical pressure vessel and including an upper riser section disposed in the upper vessel section and a lower riser section disposed in the lower vessel section; steam generators disposed inside the cylindrical pressure vessel in the upper vessel section; a reactor core comprising fissile material disposed inside the cylindrical pressure vessel in the lower vessel section; and control rod drive mechanism (CRDM) units disposed inside the cylindrical pressure vessel above the reactor core and in the lower vessel section. There is no vertical overlap between the steam generators and the CRDM units.