Nuclear Fuel Leakage Testing via Integrated Storage Rack Sipping
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Solution Overview
Problem
Current leakage testing methods for nuclear fuel assemblies are inefficient, particularly for pressurized water reactors, as they require extensive handling, are costly, and can be disrupted by fission products, leading to uncertain results and increased risk of damage.
Innovation Solution
A sipping device and method that utilize a collection assembly to close and extend the upper end of a storage rack cell, collecting gaseous and dissolved fission products while maintaining water containment, and a control assembly for analysis, allowing for efficient leakage testing directly in a storage rack without separate sipping cells, reducing handling and contamination risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If leakage testing is performed using separate sipping cells, then detection capability is improved, but device complexity and handling operations increase
Solution Approach 1:
The patent combines the sipping cell functionality directly into the storage rack structure. The collection assembly integrates the sipping chamber, water containment, and fission product collection into a unified system that eliminates the need for separate, movable sipping cells. This merging reduces handling operations while maintaining leakage detection capability.
Solution Approach 2:
The storage rack is designed to serve multiple functions: it stores nuclear fuel assemblies and simultaneously performs leakage testing through the integrated collection assembly. The collection assembly can switch between storing water for sipping tests and collecting gaseous fission products, eliminating the need for dedicated separate testing equipment.
2Ease of operation
If in-core sipping is performed, then testing can be done in reactor position, but results are disrupted by fission products from coolant and adjacent assemblies
Solution Approach 1:
The invention extracts the nuclear fuel assembly from the reactor core environment to the storage rack for leakage testing. This removal isolates the test assembly from interfering fission products present in the reactor coolant and from adjacent assemblies, enabling accurate detection while maintaining operational ease through the integrated storage rack system.
Solution Approach 2:
The collection assembly creates an isolated testing environment within the storage rack that is free from the reactive and interfering conditions of the reactor core. By performing tests in this controlled, inert-like environment separate from the coolant system, the invention eliminates interference from dissolved fission products and adjacent assembly emissions.
3Reliability
If extensive handling is performed to move assemblies for testing, then testing can be conducted, but risk of damage and time consumption increase
Solution Approach 1:
By merging the storage function and testing function into a single integrated system, the invention eliminates the need to move assemblies between separate storage and testing locations. The collection assembly is directly accessible from the storage rack position, allowing testing to be performed immediately without additional handling time or increased damage risk.
4Measurement precision
If separate sipping cells are used, then leakage testing is possible, but cost and maintenance requirements increase
Solution Approach 1:
The invention merges the sipping cell functionality into the storage rack structure, eliminating the need for separate, expensive testing cells. The collection assembly uses the existing storage rack infrastructure and can be integrated with routine maintenance activities, significantly reducing overall maintenance costs while maintaining effective leakage detection capability.
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
Enables simple, quick, and cost-effective leakage testing with reduced handling operations, minimizing interference from adjacent assemblies and improving detection accuracy by allowing testing in a storage rack, thus enhancing nuclear fuel assembly safety and reducing maintenance costs.
Implementation Method 1
A leakage testing by sipping consists of causing a relative increase in the internal pressure of the nuclear fuel rods of a nuclear fuel assembly relative to the outside pressure. Since the pressures inside and outside the fuel rod tend to balance each other out naturally, a transfer of the fission products that are essentially in gaseous form inside the rod occurs toward the outside.
Implementation Method 2
The relative increase of the internal pressure of the fuel rods is for example obtained by causing an increase in the temperature of the nuclear fuel assembly
Data Source
AI summary
A leakage testing device for testing leakage of a nuclear fuel assembly (18) by sipping. The device includes a collection assembly (32) that is configured to close an upper end (24A) of a cell (24) of a storage rack (22) for storing nuclear fuel assemblies discharged from a nuclear reactor (4). The closing prevents water contained in the cell from escaping via the upper end of the cell. The collection assembly is configured to collect products containing possible fission products released by a nuclear fuel assembly contained in the cell.