Nuclear Control Room Failure Downgrade Strategy

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Solution Overview

Problem

The conventional failure downgrade operation strategy for nuclear power plant control rooms lacks a defense line to alleviate serious accidents, mixes equipment with different defense in depth levels, and places high demands on operator accuracy, increasing the risk of human error and design defects.

Innovation Solution

The proposed method and system introduce a failure downgrade operation strategy that includes a pre-defense line using the KIC system, a main defense line with an Auxiliary Control Panel (ACP) and an Emergency Control Panel (ECP), a diversity defense line with a Diverse Human interface Panel (DHP), and a serious accident mitigation line with a Serious Accident Panel (SAP), thereby clarifying the failure downgrade operation strategy and reducing operator burden.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If BUP and ECP hardware panels are used to handle both non-safety level HSI failures and digital common mode failures, then the main defense line can respond to multiple failure types, but the devices with different defense in depth levels are mixedly arranged making it difficult to monitor the nuclear power plant

Engineering Contradiction:

Improveability to handle multiple failure typesVSAvoidmixed arrangement of devices with different defense levels

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the defense in depth system into distinct functional lines: pre-defense line (KIC system for HSI failures), main defense line (BUP+ECP for non-safety level failures), diversity defense line (DHP for digital common mode failures), and serious accident mitigation line (SAP for severe accidents). This segmentation separates devices with different defense levels into dedicated panels, eliminating mixed arrangement while maintaining comprehensive failure response capability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces a Serious Accident Panel (SAP) as a specialized intermediary component that handles serious accidents independently. This intermediary structure allows the system to address severe failure modes without interfering with the normal operation of other defense lines, thereby simplifying the overall system architecture and improving monitorability

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If the conventional failure downgrade operation strategy is used, then the existing equipment can be utilized, but the main control room defense in depth system lacks a defense line to alleviate serious accidents

Engineering Contradiction:

Improveutilization of existing equipmentVSAvoidability to handle serious accidents

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent introduces a Serious Accident Panel (SAP) equipped with independent power supply and specialized monitoring equipment that operates in advance preparation for serious accident scenarios. This preliminary action ensures that when serious accidents occur, the system can immediately respond without relying on other defense lines that may already be compromised, thereby enhancing the overall reliability of the defense in depth system

Inventive Principle:

Principle #10Preliminary action

3Reliability

If high requirements are placed on operator accuracy in HSI failure mode, then the control system can maintain safety, but the difficulty for operators to deal with HSI failure increases and the probability of human failure increases

Engineering Contradiction:

Improvesafety maintenance in failure modeVSAvoidoperator difficulty in handling failures

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent implements local quality by providing specialized panels with dedicated functions for different failure scenarios. The Serious Accident Panel (SAP) offers simplified, failure-specific controls and displays tailored to serious accident handling, reducing the cognitive burden on operators. Each defense line has its own specialized interface, allowing operators to quickly identify and respond to the specific failure mode without being overwhelmed by system complexity

Inventive Principle:

Principle #3Local quality

Data Source

PatentEP3882924B1Failure downgrade running method and system for nuclear power plant control room

Publication Date: 2025.04.16 CHINA NUCLEAR POWER DESIGN COMPANY

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AI summary

The present invention provides a failure downgrade operation method and system for a nuclear power plant control room. The method includes: using a KIC system to construct a pre-defense line in a control room defense in depth system (S11); using an ACP and an ECP to construct a main defense line in the control room defense in depth system (S12); using a DHP panel to construct a diversity defense line in the control room defense in depth system (S13); and using an SAP panel to construct a serious accident mitigation line in the control room defense in depth system (S14). Positioning of a device belonging to a serious accident defense line in a failure downgrade operation strategy is considered, the problem of the mixed arrangement of devices at different defense in depth levels and in different failure running modes is solved, the failure downgrade operation strategy of the control room is clear, and the related dedicated devices are configured to significantly reduce the difficulty that an operator handles failures of HSIs, reduce the human error probability, and improve the safety of a nuclear power plant.