Passive Cooling Spent Nuclear Fuel Pool via Conductive Shell

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Solution Overview

Problem

Conventional spent nuclear fuel pool cooling systems rely on pumps and motors, which can fail during power outages, leading to water evaporation, increased humidity, and contamination from dust and particulates, compromising the habitability and HVAC efficiency of nuclear power plant buildings.

Innovation Solution

A passive cooling system utilizing a thermally conductive containment vessel with an annular reservoir and a heat sink, relying on natural gravity-driven flow patterns and conductive heat transfer to cool the fuel pool without active components, preventing water evaporation and reducing humidity and contamination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If pumps and motors are used to cool the spent fuel pool, then cooling effectiveness is improved, but system reliability deteriorates during power outages

Engineering Contradiction:

Improvespent fuel pool water temperatureVSAvoidcooling system reliability during power outage

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The patent replaces the mechanical pump-based cooling system with a passive natural circulation system that uses density differences (thermal convection) to drive water flow through the heat exchanger, eliminating the need for electrical pumps and motors while maintaining cooling effectiveness during power outages

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The cooling system is designed to be self-regulating through natural convection currents where heated water naturally rises and flows through the heat exchanger, and cooled water naturally sinks and returns to the pool, creating a self-sustaining cooling cycle without external mechanical intervention

Inventive Principle:

Principle #25Self-service

2Temperature

If conventional pump-based cooling is used, then cooling capacity is sufficient, but water evaporation increases leading to higher humidity

Engineering Contradiction:

Improvespent fuel pool cooling capacityVSAvoidwater vapor release and humidity

Core Design Contradiction:

TemperatureVSObject-generated harmful factors

Solution Approach 1:

The patent introduces a cover or seal over the spent fuel pool that traps water vapor, preventing its release into the building atmosphere. The trapped vapor condenses on the cooler inner surface of the cover and returns to the pool, creating a closed-loop system that maintains cooling capacity while eliminating humidity problems

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent creates a controlled, sealed environment over the spent fuel pool that prevents interaction between the water vapor and the building atmosphere, effectively isolating the pool from the surrounding air space and preventing contamination and humidity buildup

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

3Temperature

If the spent fuel pool is open for cooling, then heat dissipation is effective, but dust and particulates contaminate the water

Engineering Contradiction:

Improveheat dissipation efficiencyVSAvoiddust and particulate contamination

Core Design Contradiction:

TemperatureVSObject-affected harmful factors

Solution Approach 1:

The patent implements a cover or shield over the spent fuel pool that physically blocks dust and particulates from entering the water while allowing thermal energy to escape through the cover material or designated venting areas, thus protecting water quality without compromising heat dissipation

Inventive Principle:

Principle #30Flexible shells and thin films

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

The system effectively cools the spent nuclear fuel pool without pumps or motors, maintaining a stable water level, reducing humidity, and preventing dust and particulate contamination, ensuring safe and efficient operation of nuclear power plant facilities.

Implementation Method 1

conductive heat transfer through the metal heat transfer wall of the containment vessel

Methodology Applied

Scientific EffectConductive heat transfer: Conduction (thermal)

Implementation Method 2

remove thermal energy from the received water vapor, thereby condensing the water vapor

Methodology Applied

Scientific EffectCondensation: Condensation

Implementation Method 3

natural gravity-driven flow circulation patterns

Methodology Applied

Scientific EffectGravity-driven flow: Gravitation

Data Source

PatentUS10008296B2Passively-cooled spent nuclear fuel pool system

Publication Date: 2018.06.26 SMR INVENTEC LLC

AI summary

A passively-cooled spent nuclear fuel pool system in one embodiment includes a containment vessel comprising a thermally conductive shell and an annular reservoir surrounding the shell that holds a liquid coolant forming a heat sink. A spent fuel pool is disposed inside the containment vessel and includes a body of water in contact with a peripheral sidewall of the fuel pool. At least one spent nuclear fuel rod submerged in the body of water heats the water. The peripheral sidewall of the spent fuel pool is formed by a portion of the shell of the containment vessel adjacent to the fuel pool, thereby defining a shared common heat transfer wall. The heat transfer wall operates to transfer heat from the body of water in the spent fuel pool to the heat sink to cool the body of water. The heat transfer wall comprises metal in one embodiment.