Underwater Nuclear Reactor Vessel Cutting Prevents Radiation Dust
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Solution Overview
Problem
During the decommissioning of nuclear facilities, workers are exposed to radiation and the environment is polluted due to dust generation when cutting and separating the nuclear reactor pressure vessel from the bio-protective concrete.
Innovation Solution
An underwater decommissioning method is employed, where the nuclear reactor pressure vessel is lifted above the cavity, a support part with a curved surface and steps is installed, and the vessel is cut using a cutting device while submerged, preventing dust and radiation exposure by performing the cutting operations underwater.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If cutting operations are performed on the nuclear reactor pressure vessel during decommissioning, then the vessel can be separated and decommissioned, but workers are exposed to radiation and dust pollutes the environment
Solution Approach 1:
Water is introduced as an intermediary medium to perform cutting operations on the nuclear reactor pressure vessel. The water serves multiple functions: it suppresses dust generation during cutting, provides radiation shielding to protect workers, and enables the cutting process to proceed safely. This intermediary approach resolves the contradiction by allowing decommissioning work to continue while eliminating the harmful effects of radiation exposure and dust pollution.
2Ease of manufacture
If the nuclear reactor pressure vessel is cut above ground, then cutting operations can be performed, but dust is generated causing environmental pollution
Solution Approach 1:
The patent applies hydraulic principles by using water as the cutting medium and suppressant. Water is supplied through nozzles during the cutting process, utilizing fluid dynamics to suppress dust generation while maintaining cutting effectiveness. This hydraulic approach eliminates dust pollution while preserving the feasibility of cutting operations.
3Ease of operation
If the nuclear reactor pressure vessel is lifted and repositioned, then it can be mounted on the support part for cutting, but complex lifting and positioning operations are required
Solution Approach 1:
The support part is designed with a curved surface that matches the bottom surface of the nuclear reactor pressure vessel, creating a natural fitting interface. This equipotential design allows the vessel to be positioned and secured through gravitational alignment and geometric compatibility, significantly reducing the complexity of lifting and positioning operations while maintaining operational ease.
Data Source
AI summary
An underwater decommissioning method of a nuclear facility including a nuclear reactor pressure vessel and bio-protective concrete comprising a cavity in which the nuclear reactor pressure vessel is positioned is disclosed. The method includes: (a) lifting the nuclear reactor pressure vessel above the cavity; (b) forming an insertion part in the bio-protective concrete adjacent to the cavity, filling the insertion part with water, and installing a support part on a bottom surface of the insertion part; (c) inserting the nuclear reactor pressure vessel in the insertion part and mounting a lower portion of the nuclear reactor pressure vessel on the support part; and (d) repeatedly cutting portions of the nuclear reactor pressure vessel mounted on the support part by using a cutting device in an underwater position. The method allows performing cutting operations in the water, and thus, it is possible to prevent radiation exposure due to occurrence of dust.