Depressurizing Power Generation Unit for Nuclear Steam Decontamination
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Solution Overview
Problem
Despite enhanced safety measures, severe accidents in nuclear power plants can still result in radioactive materials bypassing the containment building and being released into the atmosphere, particularly during events like steam generator tube rupture (SGTR) or interfacing-system loss-of-coolant-accident (ISLOCA).
Innovation Solution
A system comprising a steam generator, a decontamination tank filled with decontamination water, and a depressurizing power generation unit that generates emergency power while depressurizing steam from the steam generator, directing it to the decontamination tank to reduce atmospheric release of radioactive materials. This system includes valves and a configuration to manage steam pressure and prevent damage to the decontamination tank.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a decontamination tank is connected to the main steam line to decontaminate steam during severe accidents, then atmospheric release of radioactive materials is reduced, but the internal pressure of the decontamination tank may instantaneously rise due to high-temperature and high-pressure steam
Solution Approach 1:
A depressurizing power generation unit is introduced as an intermediary component between the main steam line and the decontamination tank. This unit gradually depressurizes the high-temperature and high-pressure steam before it enters the decontamination tank, preventing instantaneous pressure rise while still enabling decontamination function
Solution Approach 2:
The depressurizing power generation unit utilizes the energy of the high-pressure steam itself to generate emergency power, converting the potentially harmful high-pressure steam into useful energy while simultaneously reducing the pressure before the steam enters the decontamination tank
2Reliability
If high-pressure steam is directly delivered to the decontamination tank during severe accidents, then decontamination function is activated, but the decontamination tank may be damaged due to instantaneous pressure rise
Solution Approach 1:
The depressurizing power generation unit serves as a protective intermediary that gradually reduces steam pressure before it reaches the decontamination tank, preventing structural damage while maintaining the decontamination capability
Solution Approach 2:
The steam is preliminarily depressurized through the power generation unit before entering the decontamination tank, preparing the steam in advance to prevent tank damage from pressure shock
3Power
If steam is depressurized through a turbine during severe accidents, then emergency power is generated and steam pressure is reduced, but the turbine may not be available or sufficient for this purpose
Solution Approach 1:
The depressurizing power generation unit is designed to serve multiple functions: it acts as a depressurizing device to protect the decontamination tank and simultaneously generates emergency power for plant operations during severe accidents
Solution Approach 2:
The system changes the operational parameters of the steam by reducing its pressure and temperature through the depressurizing unit, making it suitable for the decontamination tank while generating power in the process
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
Effectively reduces the atmospheric release of radioactive materials by decontaminating steam within the containment building, preventing leaks, and providing emergency power for critical equipment during accidents, thereby enhancing nuclear power plant safety and stability.
Implementation Method 1
a depressurizing power generation unit disposed on the connection line and configured to generate emergency power while depressurizing the steam delivered from the steam generator toward the decontamination tank
Implementation Method 2
a decontamination tank connected to the main steam line through a connection line and containing decontamination water for decontaminating the steam delivered from the steam generator
Data Source
AI summary
Provided are a system and method for reducing the atmospheric release of radioactive materials caused by a severe accident. The system includes a steam generator disposed in a containment building, configured to generate steam by using heat of a coolant heated in a nuclear reactor, and connected to a turbine through a main steam line, a decontamination tank connected to the main steam line through a connection line and containing decontamination water for decontaminating the steam delivered from the steam generator and reducing atmospheric release of radioactive materials when a severe accident occurs, and a depressurizing power generation unit disposed on the connection line and configured to generate emergency power while depressurizing the steam delivered from the steam generator toward the decontamination tank when the severe accident occurs.