Dew Point Monitoring for High Level Waste Canister Drying
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for drying spent nuclear fuel canisters to meet the NRC's vapor pressure requirement of 399.97 Pa (3 Torr) or less are time-consuming, manually intensive, prone to error, and require expensive vacuum equipment, posing risks to personnel and equipment due to the need for sub-atmospheric conditions and physical access to the canister.
Innovation Solution
A closed-loop system using a non-reactive gas, such as helium, is employed to dry the canister by controlling the dew point temperature and flow rate, ensuring the cavity is adequately dry without physically measuring the vapor pressure, thus eliminating the need for sub-atmospheric conditions and expensive vacuum equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If vacuum drying method is used to meet NRC vapor pressure requirement, then drying effectiveness is improved, but device complexity and cost increase due to expensive vacuum equipment and sub-atmospheric conditions
Solution Approach 1:
The invention changes the measurement parameter from vapor pressure to dew point temperature. By controlling and measuring dew point temperature of the gas stream, the system achieves equivalent drying verification without requiring vacuum equipment or sub-atmospheric conditions, thus simplifying the device while maintaining drying effectiveness
Solution Approach 2:
The invention replaces the mechanical vacuum system with a gas flow-based drying and measurement system. Instead of using vacuum pumps and maintaining sub-atmospheric pressure, the system uses controlled gas flow through the canister and measures dew point temperature, eliminating complex mechanical vacuum equipment
2Manufacturing precision
If vacuum drying method is used, then drying effectiveness is improved, but safety deteriorates due to personnel exposure risks and equipment complications
Solution Approach 1:
By replacing the vacuum system with a pressurized or atmospheric gas flow system, the invention eliminates the safety hazards associated with sub-atmospheric conditions. The gas flow method operates at normal or elevated pressures, removing the risk of vacuum-related equipment failure and personnel exposure
3Measurement precision
If manual vacuum monitoring and dryness testing is performed, then measurement accuracy is improved, but productivity deteriorates due to time-consuming manual operations
Solution Approach 1:
The invention implements continuous automated feedback monitoring by measuring dew point temperature of the gas stream in real-time. The system automatically adjusts the drying process based on dew point readings, eliminating manual monitoring while maintaining measurement accuracy and improving productivity through automated control
Solution Approach 2:
The system performs self-monitoring and self-adjustment by continuously measuring dew point temperature and automatically controlling the drying process. The automated system eliminates the need for manual intervention, achieving both measurement accuracy and high productivity
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 method is more efficient, cost-effective, and safer, as it ensures the canister is adequately dried without exposing personnel to radiation and reduces equipment complications, while being easy to implement and less prone to errors.
Implementation Method 1
the cavity is filled with a non-reactive gas and a flow rate of the non-reactive gas through the cavity is controlled so as to carry water vapor away from the cavity
Implementation Method 2
the wetted non-reactive gas is then passed through a chiller that removes the moisture
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A system and method for drying cavities loaded with high level waste ("HLW") is devised. The invention utilizes a non-intrusive procedure that is based on monitoring the dew point temperature of a non-reactive gas that is circulated through the cavity. In one aspect, the invention is a method comprising: a) flowing a non-reactive gas through the cavity; b) repetitively measuring the dew point temperature of the non-reactive gas exiting the cavity; and c) upon the dew point temperature of the non-reactive gas exiting the cavity reaching and remaining below a predetermined dew point temperature for a predetermined time, discontinuing the flow of the non-reactive gas and sealing the cavity. In another aspect, the invention is a system designed to carry out the method.