Ventilated Metal Overpack for Transfer-Cask-Free Spent Fuel Storage
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Solution Overview
Problem
The existing methods for transferring hazardous radioactive spent nuclear fuel from contaminated pools to dry storage involve costly and time-consuming use of transfer casks, requiring significant human resources and complex operations.
Innovation Solution
A simplified economic ventilated metal storage system (SEVMSS) that loads and stores radioactive spent nuclear fuel in a metal canister within a passively ventilated metal overpack on a dry storage pad without using a transfer cask, utilizing a metal insert ring and basin cup to seal the annulus space during pool immersion and a ventilated lid for airflow, enabling efficient dry storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a transfer cask is used to transport canisters from the contaminated pool, then safe transfer of fuel is ensured, but substantial time, costs, and human resources are consumed
Solution Approach 1:
The patent combines the transfer cask function with the storage overpack into a single integrated system. The overpack serves both as the storage container and as the transfer vehicle, eliminating the need for a separate transfer cask. The canister is placed directly into the overpack within the pool, and the overpack is then lifted and transported to the storage site as a complete unit.
Solution Approach 2:
The overpack is designed to perform multiple functions: it serves as the storage container for the canister, as the transfer vehicle for moving the canister from the pool to storage, and as the final storage structure at the dry storage site. This multi-functionality eliminates the need for specialized transfer casks.
2Reliability
If a transfer cask is used to transport canisters from the contaminated pool, then safe transfer of fuel is ensured, but costly equipment and complex operations are required
Solution Approach 1:
The patent combines the transfer cask function with the storage overpack into a single integrated system. The overpack serves both as the storage container and as the transfer vehicle, eliminating the need for a separate transfer cask. The canister is placed directly into the overpack within the pool, and the overpack is then lifted and transported to the storage site as a complete unit.
Solution Approach 2:
The patent extracts the transfer cask from the system entirely, removing the complex equipment and procedures associated with it. By placing the canister directly into the overpack within the pool and using the overpack as the transfer vehicle, the system eliminates the intermediate transfer cask step.
3Object-affected harmful factors
If the overpack is sealed during pool immersion, then contamination is prevented, but ventilation is blocked for dry storage
Solution Approach 1:
The overpack employs dynamic sealing components that change state based on the operational phase. During pool immersion, the water-activated seal engages to prevent contamination. During dry storage, the seal disengages or becomes permeable to allow passive ventilation. This dynamic behavior allows the same structure to serve both containment and ventilation functions.
Solution Approach 2:
The seal's properties change based on environmental parameters. In the presence of water during pool immersion, the seal becomes activated and closed to prevent contamination. When transferred to dry storage conditions, the seal's properties change to allow ventilation while maintaining structural integrity.
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
This approach significantly reduces time, cost, and human resource requirements by eliminating the need for transfer casks, while ensuring safe and efficient handling and storage of radioactive materials.
Implementation Method 1
a passively ventilated metal overpack on a dry storage pad
Implementation Method 2
provides mechanical protection, passive heat removal features, and additional radiation shielding
Data Source
AI summary
Disclosed are various embodiments of a simplified economic ventilated metal storage system (SEVMSS) for enabling hazardous radioactive spent nuclear fuel in a contaminated pool to be loaded and stored in a metal canister and then placed within a passively ventilated metal overpack on a dry storage pad, without use of a transfer cask. The embodiments use an insert ring and a basin cup at respectively the top and bottom of the overpack to seal the annulus space of the overpack while the overpack resides in the pool. After cooling of the overpack and removal from the pool, the insert ring is replaced with a vented lid and the basin cup is removed. The overpack with canister is then placed on the dry storage pad with a seismic stability ring attached to its bottom or is placed in a recessed opening of a ventilated storage pad.