Description:
Reference #: 01367
The University of South Carolina is offering licensing opportunities for Water Vapor Quantification Methodology during Drying of Spent Nuclear Fuel
Background:
Spent fuel rods from nuclear reactors are initially kept in spent fuel pools to allow radioactivity to die away to levels that these rods can be stored in dry cask. After being transferred to the dry cask storage, the rods are sealed in a canister shrouded in inert gas and protected by an overpack of concrete that also serves as a radiation shield. The purpose of drying is to remove the water left in the canister and fuel assemblies to ensure the long term integrity and retrievability of the spent fuel assemblies.
The drying is performed as a vacuum drying process or a forced gas re-circulation process. Vacuum drying with pressure hold points that indirectly relates to the available water vapor content in the fuel canister is the most common industry practice to certify the “dryness” level of the system.
In-line moisture content detection and quantification in these fuel canisters is generally hindered by conventional humidity sensors posing several limitations like low sensitivity to moisture detection, inconsistency in ascertaining the end point of the drying process, quantifying the absolute ‘mass’ of water leaving the system and therefore, remains a topic of research interest.
Among the different non-intrusive techniques of water vapor detection and quantification, non-thermal plasma discharge bears the potential to overcome many limitations.
Invention Description:
The methodology and device can detect and quantify water vapor concentration in spent nuclear fuel rods undergoing the drying processes needed for safe storage purposes.
Advantages and Benefits:
There are currently no similar products available. Regular off-the-shelf relative humidity sensors do not operate under these conditions and do not provide a direct quantification of water vapor content.
This emission based detection is insensitive to any type of radiation effect from spent nuclear fuel rods, and the device and methodology has extremely high sensitivity.
The system is modular, easily manufactured, and can be readily installed in spent nuclear fuel casks for continuous monitoring of water content. A continuous monitor can also promote safety by providing warning signs associated with catastrophic system failure from free hydrogen available in the system due to residual water and water vapor.