Radioactive Waste Canister Lid Segmentation and Ventilation
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Solution Overview
Problem
Current systems for storing high-level radioactive waste, such as spent nuclear fuel, face challenges including radiation exposure risks for personnel, inefficiencies in heat rejection due to wind effects, high costs and weight of thick lids, and inadequate leak testing methods that increase radiation exposure and maintenance needs.
Innovation Solution
A vertical ventilated overpack system with a cylindrical design featuring a unique air inlet and outlet vent configuration, a detachable lid assembly with a shielded lifting lid for reduced radiation exposure, and a method for leak testing using a hermetically sealed interstitial space and conduit for minimizing exposure and maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a thick lid is used to shield personnel from radiation, then radiation protection is improved, but the weight and cost of the canister increase significantly
Solution Approach 1:
The lid is divided into two separate components: a thin confinement lid that provides radiation shielding and a separate shielded lifting lid that provides additional radiation protection during lifting operations. This segmentation allows each lid to be optimized for its specific function, reducing the overall weight compared to a single thick lid while maintaining radiation protection.
Solution Approach 2:
A bolt hole cover is introduced as an intermediary component that provides localized radiation shielding at the bolt holes during lifting operations. This eliminates the need for the entire lifting lid to be thick, as radiation protection is provided only where needed (at the bolt holes) rather than across the entire lid surface.
2Object-affected harmful factors
If a thick lid is used to shield personnel from radiation, then radiation protection is improved, but the manufacturing cost increases
Solution Approach 1:
The lid system is segmented into multiple thinner components (confinement lid, lifting lid, bolt hole covers) rather than one thick lid. This segmentation reduces material costs and manufacturing complexity while achieving the same or better radiation protection through strategic placement of shielding at critical locations.
Solution Approach 2:
The bolt hole covers are designed as separate, removable components that can be easily manufactured and replaced. These thin, localized shields provide cost-effective radiation protection only where needed during lifting operations, eliminating the expense of making the entire lid thick.
3Reliability
If conventional leak testing methods are used, then leak detection is performed, but radiation exposure to personnel increases and maintenance needs increase
Solution Approach 1:
A conduit with a removable seal is introduced as an intermediary that provides a sealed pathway from the interstitial space to the external environment. This allows leak testing to be performed by drawing air through the conduit without opening the canister, thereby eliminating radiation exposure to personnel while maintaining reliable leak detection capability.
4Device complexity
If natural convection is used for heat rejection, then system complexity is reduced, but wind effects reduce heat rejection efficiency
Solution Approach 1:
The overpack has a cylindrical shape with curved surfaces that promote uniform airflow patterns and reduce wind-induced flow separation. The curved geometry helps maintain stable natural convection currents while minimizing the negative effects of wind direction changes, thereby maintaining heat rejection efficiency without adding system complexity.
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 system reduces radiation exposure risks, enhances heat rejection efficiency, decreases the weight and cost of storage containers, and improves leak detection capabilities, facilitating safer and more efficient storage and transfer of high-level radioactive waste.
Implementation Method 1
an air inlet vent for introducing cool air into the cavity and an air outlet vent in the overpack lid for removing warmed air from the cavity
Implementation Method 2
a method for leak testing using a hermetically sealed interstitial space and conduit for minimizing exposure and maintenance
Data Source
AI summary
A container system for radioactive waste and method for using the same is provided. The system includes a canister configured for holding radioactive waste and a lid system. In one embodiment, the lid system comprises a two-part lid assembly including a confinement lid and a shielded lifting lid. The confinement lid is detachably mounted to the confinement lid. In use, the lifting lid supports the confinement lid for lifting and placement on the canister. The lifting lid further shields operators while the confinement lid is mounted to the canister. Thereafter, the lifting lid is removed and may be reused for confinement lid mountings on other canisters. In one embodiment, the confinement lid is bolted to the canister. The canister may be disposed in a protective overpack for transport and storage.