Integrated Emergency Condenser for PWR Pressure Vessel
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In pressurized water reactors (PWRs), abnormal events such as loss of coolant accidents (LOCA) can lead to rapid pressure and temperature increases, compromising the integrity of the pressure vessel and potentially causing radioactive releases, due to the lack of effective control over primary coolant pressure and temperature.
Innovation Solution
The integration of high-pressure condensers directly mounted on the pressure vessel, with shortened steam connections to the internal pressurizer volume, functioning as passive heat exchangers to condense steam and reject heat to an external heat sink, thereby reducing the risk of LOCA severity and providing rapid cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If condensers are integrated directly on the pressure vessel with shortened steam connections, then the likelihood of condenser rupture is reduced and fluid resistance is minimized, but the device complexity increases due to direct mounting requirements
Solution Approach 1:
The condenser is merged with the pressure vessel structure through direct mounting, eliminating the need for separate long steam connections. This integration reduces the number of potential failure points (rupture likelihood) and minimizes fluid resistance while maintaining structural integrity through the combined design.
Solution Approach 2:
The steam connection system is segmented into shortened internal passages within the pressure vessel rather than external long connections. This segmentation reduces the total length of vulnerable piping while maintaining functional separation between the condenser and external environment.
2Productivity
If condensers are integrated directly on the pressure vessel, then fluid resistance is minimized and condensation efficiency is improved, but manufacturing precision requirements increase
Solution Approach 1:
By merging the condenser mounting directly onto the pressure vessel, the patent eliminates the need for precision alignment of separate connection pipes. The integrated structure allows for more tolerant manufacturing while achieving optimal fluid flow paths that minimize resistance and maximize condensation efficiency.
3Speed
If high-pressure condensers are used for emergency cooling, then rapid cooling capability is improved, but the heat sink capacity requirements increase
Solution Approach 1:
The condenser is pre-configured and pre-charged with cooling fluid before emergency conditions occur. This preliminary preparation allows immediate activation of rapid cooling capability when needed, eliminating delays while the heat sink capacity is designed to match the maximum anticipated thermal load rather than continuous operation requirements.
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 configuration reduces the likelihood of condenser rupture, minimizes fluid resistance, and enables efficient condensation of steam, thereby mitigating pressure increases and containing primary coolant releases, enhancing safety by reducing the severity of LOCA events and maintaining reactor stability.
Implementation Method 1
a condenser supported by the upper portion of the pressure vessel... condense steam in the event of a LOCA or loss of heat sinking event
Implementation Method 2
reject heat to an external heat sink
Implementation Method 3
heat (i.e., energy) is transferred from the reactor core to the secondary coolant water via the intermediary of the primary coolant water
Data Source
AI summary
A pressurized water nuclear reactor (PWR) includes a pressure vessel having a lower portion containing a nuclear reactor core comprising a fissile material and an upper portion defining an internal pressurizer volume. A condenser is secured to, and optionally supported by, the upper portion of the pressure vessel. A condenser inlet is in fluid communication with the internal pressurizer volume. A heat sink is in fluid communication with the condenser such that the condenser operates as a passive heat exchanger to condense steam from the internal pressurizer volume into condensate while rejecting heat to the heat sink. A condenser outlet connects with the pressure vessel to return condensate to the pressure vessel. A single metal forging having a first end welded to the pressure vessel and a second end welded to the condenser inlet may provide the fluid communication between the condenser inlet and the internal pressurizer volume.