HTGR Steam Generator Pressure Inversion Safety

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Solution Overview

Problem

In high temperature gas cooled reactor steam generation systems, there is a risk of high pressure water or steam entering the nuclear reactor if the heat transfer tube is damaged, potentially causing a hydrogen explosion due to the reaction of graphite and water, as the pressure of the secondary coolant in the steam generator is higher than that of the primary coolant in the nuclear reactor.

Innovation Solution

A high temperature gas cooled reactor steam generation system is designed with pressure adjustment means to set the secondary coolant pressure in the steam generator lower than the primary coolant pressure in the nuclear reactor, using components such as primary coolant storage units, secondary coolant discharging units, and flow rate variable units to control the pressure difference and prevent coolant entry into the nuclear reactor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the steam pressure in the steam generator is set to be higher than the helium gas pressure in the nuclear reactor to improve steam generation efficiency, then the steam turbine power output is improved, but when a heat transfer tube is damaged, high pressure water or steam may enter the nuclear reactor causing graphite corrosion and hydrogen explosion risk

Engineering Contradiction:

Improvesteam turbine power outputVSAvoidwater entry into nuclear reactor

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

The patent inverts the conventional pressure relationship by setting the steam generator pressure lower than the reactor pressure. This reverses the expected pressure gradient, preventing water entry into the reactor while maintaining system functionality through alternative steam generation methods

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent implements preliminary protective measures including water entering suppression devices and pressure control mechanisms that actively prevent the harmful effect of water entry before it can occur, countering the potential danger in advance

Inventive Principle:

Principle #9Preliminary anti-action

2Reliability

If a water entering suppression device is installed to prevent water from entering the nuclear reactor, then safety is improved, but the device complexity and system cost increase

Engineering Contradiction:

Improveprevention of water entryVSAvoidsystem structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Instead of adding complex suppression devices to prevent water entry, the patent inverts the pressure relationship fundamentally, making the prevention function inherent to the system design rather than requiring additional protective components

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent extracts the essential safety function from complex suppression devices and integrates it into the basic pressure control system, removing unnecessary device complexity while maintaining reliability

Inventive Principle:

Principle #2Taking out (Extraction)

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 effectively prevents high pressure water or steam from entering the nuclear reactor, reducing the risk of hydrogen explosions and improving thermal efficiency by optimizing the pressure and temperature settings in the steam generation system.

Implementation Method 1

a steam generator that has water as a secondary coolant and heats the secondary coolant by the primary coolant via the nuclear reactor to generate steam

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

a steam turbine that is operated by the steam from the steam generator; a generator that generates electricity according to an operation of the steam turbine

Methodology Applied

Scientific EffectThermal energy conversion: Heat Engine

Data Source

PatentUS9959945B2High temperature gas cooled reactor steam generation system

Publication Date: 2018.05.01 MITSUBISHI HEAVY IND LTD

AI summary

A high temperature gas cooled reactor steam generation system (1) includes a nuclear reactor (2) that has helium gas as a primary coolant and heats the primary coolant by heat generated by a nuclear reaction that decelerates neutrons by a graphite block, a steam generator (3) that has water as a secondary coolant and heats the secondary coolant by the primary coolant via the nuclear reactor (2) to generate steam, a steam turbine (4) that is operated by the steam from the steam generator (3), and a generator (5) that generates electricity according to an operation of the steam turbine (4). Moreover, the system (1) includes pressure adjustment means for setting a pressure of the secondary coolant in the steam generator (3) to be lower than a pressure of the primary coolant in the nuclear reactor (2).