Passive Pressure Suppression Pool Cooling System for Nuclear Reactors
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Solution Overview
Problem
Current nuclear power plant cooling systems, such as the isolation condenser and core isolation cooling systems, face limitations in operating duration and cost due to the need for large-capacity cooling pools and batteries for prolonged operation without external power, and they either fail to remove decay heat or increase pressure suppression pool temperatures.
Innovation Solution
A passive pressure suppression pool cooling system that uses steam from the reactor pressure vessel to condense in an external steam condenser and release condensed water back into the pressure suppression pool, allowing for passive operation without external power and reducing temperature increases in the primary containment vessel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If a large-capacity cooling pool is installed for prolonged operation of the isolation condenser, then the operation duration is extended, but the construction cost increases due to maintaining quake resistance
Solution Approach 1:
The invention extracts the cooling function from a large-capacity cooling pool and relocates it to a small-capacity cooling pool positioned above the reactor pressure vessel. The cooling function is achieved by introducing steam from the reactor pressure vessel into the cooling pool, where it condenses and releases heat to the cooling water, eliminating the need for a large quake-resistant structure
Solution Approach 2:
The invention uses a small-capacity cooling pool with just enough volume to sustain condensation for the required duration (e.g., 72 hours). By positioning the pool above the reactor pressure vessel and using steam-driven condensation, the system achieves prolonged operation without requiring excessive cooling water volume that would necessitate a large construction
2Duration of action of moving object
If a pump is installed to supply cooling water to the reactor pressure vessel in the core isolation cooling system, then cooling water can be supplied without external power, but a large-capacity battery is needed for prolonged operation
Solution Approach 1:
The invention makes the cooling system self-service by using steam from the reactor pressure vessel itself as the driving force. The steam drives the pump through a turbine, creating a self-sustaining cycle where the decay heat generation directly powers the cooling water circulation without requiring external batteries or power sources
Solution Approach 2:
The invention merges the decay heat removal function with the cooling water supply function. The steam that would otherwise be wasted is utilized to drive the pump, combining two functions (heat removal and water circulation) into a single integrated system that eliminates the need for separate battery power sources
3Loss of energy
If steam is introduced to the pressure suppression pool to release decay heat, then the decay heat is removed, but the cooling water in the reactor pressure vessel decreases and must be replenished
Solution Approach 1:
The invention recovers the steam that would otherwise be discarded into the pressure suppression pool. By introducing the steam into the cooling pool above the reactor pressure vessel, the system condenses the steam back into water, which then returns to the reactor pressure vessel, thus recovering both the heat removal function and the cooling water quantity
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
Enables prolonged, cost-effective cooling of the pressure suppression pool without external power, reducing the need for large-capacity cooling pools and batteries, while effectively managing decay heat and maintaining containment vessel pressure.
Implementation Method 1
steam is drawn from the reactor pressure vessel to be passed through the heat exchanger pipe and thereby is condensed into condensed water
Implementation Method 2
cooling water for which a certain period of operation can be secured is filled; steam from a reactor pressure vessel is introduced into the cooling water to be condensed
Implementation Method 3
the cooling water is gradually heated, and when the temperature of the cooling water in the cooling pool reaches the boiling point
Data Source
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AI summary
A nuclear power plant has a reactor pressure vessel (1), a primary containment vessel (3) and a passive pressure suppression pool cooling system. The reactor pressure vessel (1) is installed in the primary containment vessel (3). A pressure suppression pool (7) filled with cooling water is formed in a lower portion of the primary containment vessel (3). The passive pressure suppression pool cooling system is provided with a steam condensing pool (5) in which cooling water is filled, disposed outside the primary containment vessel (3), a steam condenser (4) disposed in the steam condensing pool (5), a steam supply pipe (2) connecting the reactor pressure vessel (1) to the steam condenser (4), and a condensed water discharge pipe (6) connected to the steam condenser (4) for discharging condensed water generated in the steam condenser (4). Another end portion of the condensed water discharge pipe (6) is disposed in the pressure suppression pool (7).