Nuclear Reactor Thermal Sleeve Captive Device
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Solution Overview
Problem
The existing primary circuits of nuclear reactors with thermal sleeves are prone to detachment due to fluid flow stresses, leading to potential damage and reduced functionality, as the sleeves can vibrate and be carried away by the primary fluid, causing thermal fatigue and safety issues.
Innovation Solution
A captive device with reliefs on the tapping and sleeve is implemented to prevent the sleeve from sliding into the primary piping if detached, featuring a ring and studs that cooperate to keep the sleeve confined, and a forced circulation path within the annular space to ensure fluid homogeneity and prevent stagnation zones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sleeve protrudes into the internal volume of the primary pipe to move the injection zone towards the center, then thermal fatigue at the tapping is reduced, but the sleeve is subjected to flow forces and may vibrate or detach
Solution Approach 1:
A captive device is introduced as an intermediary element between the sleeve and the primary circuit. This device includes a retention structure that prevents the sleeve from detaching while allowing it to maintain its protruding position for thermal protection. The captive device mediates between the need for thermal fatigue resistance and the risk of flow-induced detachment.
2Reliability
If the sleeve is securely attached to the tapping to prevent detachment, then reliability is improved, but the structure becomes more complex
Solution Approach 1:
The captive device is segmented into distinct functional elements: a retention structure for preventing detachment, and a circulation path structure for ensuring fluid flow. This segmentation allows each element to perform its specific function efficiently while keeping the overall design manageable and maintainable.
3Stability of the object's composition
If the annular space between the sleeve and tapping is reduced to prevent stagnation, then fluid homogeneity is improved, but the sleeve may be more prone to detachment
Solution Approach 1:
The captive device incorporates a dynamic retention mechanism that adapts to flow conditions. The circulation path is designed to work in conjunction with the retention structure, allowing the system to maintain both fluid homogeneity and sleeve stability under varying flow conditions through dynamic interaction between the fluid and the structured elements.
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 solution effectively prevents sleeve detachment and ensures continuous operation by maintaining the sleeve within the tapping, reducing thermal fatigue and preventing fluid stagnation, thereby enhancing the safety and reliability of the primary circuit.
Implementation Method 1
a primary pipe, having an internal surface delimiting an internal volume in which circulates a primary fluid for cooling the nuclear reactor
Implementation Method 2
a forced circulation path within the annular space to ensure fluid homogeneity and prevent stagnation zones
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
This nuclear reactor primary circuit (10) comprises: a primary pipe (30) having an internal surface bounding an internal volume (32) in which a primary coolant of the nuclear reactor flows; a branch pipe (34) fixed to the primary pipe (30) and bounding an internal passage (38) communicating with the internal volume (32) of the primary pipe (30); and a sleeve (36), having a first end (50) joined to the branch pipe (34) and a second free end (52) engaged in the internal volume (32) of the primary pipe (30), the second end (52) protruding into the internal volume (32) relative to the internal surface over a non-zero length, an annular space (54) being bounded between the sleeve (36) and the branch pipe (34). The primary circuit (10) comprises a device (60) for locking the sleeve (36), the locking device (60) comprising at least one first relief (62) formed in the branch pipe (34), at least one second relief (64) formed in the sleeve (36) and capable of interacting with the first relief (62) in order to prevent the sleeve (36) from falling into the primary pipe (30) if the sleeve (36) detaches from the branch pipe (34).