Nuclear Reactor Control Rod Separation Checking Mechanism
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing reactivity control devices in nuclear reactors fail to ensure effective separation between the drive rod and the control rod cluster during maintenance operations, leading to potential accidental rises of the control rod cluster and radiation protection issues.
Innovation Solution
A control assembly featuring a reactivity control device with a movable attachment device between connection and disconnection positions, and a checking device comprising a probe rod that indicates effective separation by relative displacement observation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If visual checking is performed by the operator to verify separation between drive rod and control rod cluster, then the checking method is simple, but the checking process is time-consuming and unreliable due to the large amount of upper internal equipment
Solution Approach 1:
A probe rod is introduced as an intermediary element to check the separation between the drive rod and control rod cluster. The probe rod is received in the sleeve formed by the drive rod and attachment device, and its displacement relative to the drive rod indicates whether effective separation has occurred. This intermediary mechanism provides a reliable and quick checking method without requiring complex visual inspection of the entire upper internal equipment area.
2Reliability
If the attachment device is designed to be movable between connection and disconnection positions, then the separation reliability is improved, but the device complexity increases
Solution Approach 1:
The attachment device is designed with dynamic characteristics, allowing it to move between a connection position (when rigidly attached to the control rod cluster) and a disconnection position (when separated). This dynamic design enables reliable separation during maintenance operations while maintaining a relatively simple structure through controlled movement rather than complex mechanical systems.
3Measurement precision
If the probe rod length is greater than the drive rod length, then the checking capability is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The probe rod is designed with a length parameter that is greater than the drive rod length, creating a measurable displacement difference when separation occurs. This parameter change provides sufficient measurement precision for detecting separation effectiveness. The design accommodates manufacturing variations by ensuring the length difference is sufficiently large to be reliably detected, reducing the stringency of precision requirements while maintaining checking capability.
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 control assembly ensures safe and effective separation of the drive rod from the control rod cluster, preventing unexpected rises and facilitating safe reinsertion, thus enhancing reactor maintenance safety and efficiency.
Implementation Method 1
In the event of an incident, the rod cluster control assemblies are released and fall rapidly by gravity into the fuel elements in order to stop the nuclear reaction.
Data Source
AI summary
A nuclear reactor control assembly includes a reactivity control device comprising a control rod cluster and a drive rod. The control rod cluster comprises an attaching head. The drive rod comprises an attaching device for connecting the drive rod to the attaching head. The attaching device is movable between a connection position and a disconnection position. The drive rod and the attaching device define an axial trough recess forming a sleeve. A checking device is used for checking separation between the control rod cluster and the drive rod. The checking device comprises a probe rod which is free to move translationally in the sleeve. A lower end of the probe rod can abut the attaching head. Relative displacement of the probe rod with respect to the drive rod can be used to determine whether the drive rod is separated from the control rod cluster.