Steam Generator Deposit Sampling via Primary Side Access
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Solution Overview
Problem
Current methods for sampling hard deposits from the secondary side of a steam generator in nuclear power plants are impractical due to restricted space and the inability of existing cleaning processes to remove glass-hard deposits, necessitating a more effective sampling tool and method.
Innovation Solution
A method and device that involves removing a steam generator tube to expose a heating tube bore, allowing a removal tool to be inserted from the primary side to mechanically loosen and collect samples of hard deposits, which are then transported to the primary side for removal, utilizing a rotating milling or grinding head and a collection container.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a removal tool is inserted through the manhole on the secondary side to sample deposits, then the sampling can be performed directly on the deposit surface, but the restricted space makes this approach impractical
Solution Approach 1:
Instead of inserting the removal tool from the secondary side through the manhole, the invention inverts the approach by inserting the tool from the primary side through the heating tube bore. This reversal of direction provides adequate space for tool manipulation while still enabling effective sampling of deposits on the secondary side.
Solution Approach 2:
The removal tool is inserted through the heating tube bore, which itself is nested within the tube bundle structure. This nesting approach allows the tool to access the deposit surface while passing through the constrained geometry of the existing tube bore rather than requiring external access through the manhole.
2Ease of manufacture
If spray cleaning processes are used on the secondary side, then soft deposits can be removed, but hard or encrusted deposits up to glass hardness cannot be removed
Solution Approach 1:
The invention replaces the chemical/thermal spray cleaning process with a mechanical removal system. A rotating removal tool with cutting or grinding elements mechanically breaks down and removes hard, encrusted deposits that are resistant to spray cleaning, enabling sampling of glass-hard deposits.
3Ease of operation
If a steam generator tube is removed to expose the heating tube bore, then access for the removal tool is improved, but the sealing and mechanical stabilization must be restored afterward
Solution Approach 1:
The tube removal is performed as a preliminary action before deposit sampling. By removing the tube in advance, the heating tube bore is exposed and provides direct access for the removal tool. The tube is then reinstalled and sealed after sampling is complete, restoring the system's 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
Enables efficient sampling of hard deposits from the secondary side by creating access through the heating tube bore, allowing for targeted and controlled removal of samples, even in restricted spaces, improving the ability to analyze the composition of deposits.
Implementation Method 1
Some of the deposits are then mechanically loosened with the removal tool. The dissolved deposits form the sample.
Implementation Method 2
The removal tool is therefore part of the device according to the invention according to independent claim 4, which is explained in more detail below. The removal tool and possibly other parts of the device are introduced into the steam generator through the manhole on the primary side
Data Source
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AI summary
The invention relates to a method for taking a sample (50) of a deposit (28) on a secondary side (26) of a pipe base plate (10) of a steam generator (4) of a nuclear power plant (2). Said method consists of the following: a steam generator pipe (22) is removed from the pipe base plate (10) in order to expose a hot pipe bore (20) penetrating said pipe base plate (10), a removal tool (38) of a device (36) for taking the sample (50) is introduced into the hot pipe bore (20) by the primary side (24) of the pipe base plate (10) which is opposite the secondary side (26), one part of the deposit (28) is mechanically removed by the removal tool (38) as a sample (50), the sample (50) is transported through the hot pipe bore (20) to the primary side and removed from the steam generator (4), the removal tool (38) is removed from the steam generator (4). Said device for (36) taking a sample (50) contains a removal tool (38) which can be introduced by a primary side (24) of the pipe base plate (10) which is opposite the secondary side (26) in an exposed hot pipe bore (20) penetrating the pipe base plate (10) for mechanically removing one part of the deposit (28) as a sample (50).