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 2129 views |
 Technical Discussions | | Justin Goranson
 | Justin Goranson
|  08:46 Mar-27-2001
Corrosion under scale or insulation We are looking for a method of testing for corrosion of steel in Nuclear Waste tanks. There is a layer of scale or sludge on most of the walls, and we need a way of either using the technique without removing all of the scale(preferable), or a method of detection after it has been removed, which will cause the surface to be rough
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| | | |  Tore Ausland
Consultant
Norway, Joined Mar 2001,  3 | | 00:05 Mar-27-2001
Re: Corrosion under scale or insulation : We are looking for a method of testing for corrosion of steel in Nuclear Waste tanks. There is a layer of scale or sludge on most of the walls, and we need a way of either using the technique without removing all of the scale(preferable), or a method of detection after it has been removed, which will cause the surface to be rough
.
If you are looking for a permanent coorosion monitoring I will suggest FSM-IT. I am not sure of your access to install FSM-IT on tank surface outside, but if you have this is a very god corrosion monitoring tool.
FSM-IT (Field Signature Method) is a technology great even fore long time (lifetime e.g. 30 year)monitoring. General features:
-Operator independent readings.
-Can be used for complex geometry (bends, T-bends, y-bends etc..
- Can be used in high temperature environments (up to 400°C)
-Monitors weld Corrosion
- Remote operation.
-Very high sensitivity compared to e.g. UT
-Sensitivity increases as defects develope. Operator kit with portable instrument and trend software for analysis, reporting. Best Regards
Tore Ausland
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| | | | John O'Brien
Consultant, -
Chevron ETC , USA, Joined Jan 2000, 280  | | 03:30 Mar-27-2001
Re: Corrosion under scale or insulation We use an Acoustic Emission technique on listening and grading corrosion activity in Bulk Liquid Storage Tanks (carbon Steel). Technique works well as the floors are inaccessible and we want to know the condition of the floor plate (whilst scale and sludge) present to determine which tanks to shutdown for inspection.
There is now a portable version developed from a french Petrochemical roject which can be used by untrained (equipment only) operators to do periodic surveys or as permennetly installed sensors.
If you are interested email me direct and I will give you contact details for the technology.
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| | | |  Cameron Waters
Director, Asia Pacific
Applus RTD, Australia, Joined Nov 1999, 5 |
Cameron Waters
Director, Asia Pacific
Applus RTD,
Australia,
Joined Nov 1999
5
| 02:30 Mar-28-2001
Re: Corrosion under scale or insulation  : : We are looking for a method of testing for corrosion of steel in Nuclear Waste tanks. There is a layer of scale or sludge on most of the walls, and we need a way of either using the technique without removing all of the scale(preferable), or a method of detection after it has been removed, which will cause the surface to be rough
Justin,
The INCOTEST would be perfect for what you are try to achieve, it can take reading either through the scale or direct in contact with the very rough surface. See our web page for a brief explanation of the technique. Where are you based as there are only a limited number of approved users for the INCOTEST system in the world and I will be able to point you to the one nearest to you. What is the wall thickness you are trying to measure?? Cheers ============================================
Cameron Waters
pndt
Manager - Advanced Inspection Services
143 Cambridge Street
West Leederville, Perth Western Australia
Ph. +61+8+9382 3844
Fax +61+8+9382 4458
Mobile 0419 831 893
http://www.pndt.com.au
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| | | |  S.V.Swamy
Engineering, - Material Testing Inspection & Quality Control
Retired from Nuclear Fuel Complex , India, Joined Feb 2001, 787 |
S.V.Swamy
Engineering, - Material Testing Inspection & Quality Control
Retired from Nuclear Fuel Complex ,
India,
Joined Feb 2001
787
| 02:35 Mar-29-2001
Re: Corrosion under scale or insulation Do you plan to access the tank wall from outside, as is the usual practice? If so, an ultrasonic thickness gauge with A-scan display will do in many cases. If the area is highly radioactive, then you will have to think of a permanently installed probe with read out from outside the area. Let me know whether you have tried this approach - Swamy : We are looking for a method of testing for corrosion of steel in Nuclear Waste tanks. There is a layer of scale or sludge on most of the walls, and we need a way of either using the technique without removing all of the scale(preferable), or a method of detection after it has been removed, which will cause the surface to be rough
.
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| | | | Fred Raco
Director
CP Industries - Div. of Reunion Industries, Inc., USA, Joined Jan 2001, 6 |
Fred Raco
Director
CP Industries - Div. of Reunion Industries, Inc.,
USA,
Joined Jan 2001
6
| 04:55 Mar-29-2001
Re: Corrosion under scale or insulation : Do you plan to access the tank wall from outside, as is the usual practice? If so, an ultrasonic thickness gauge with A-scan display will do in many cases. If the area is highly radioactive, then you will have to think of a permanently installed probe with read out from outside the area. Let me know whether you have tried this approach - Swamy
.
: : We are looking for a method of testing for corrosion of steel in Nuclear Waste tanks. There is a layer of scale or sludge on most of the walls, and we need a way of either using the technique without removing all of the scale(preferable), or a method of detection after it has been removed, which will cause the surface to be rough
: .
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The suggestion of using an A-Scan machine is a good one. May I add that it would be more accurate to use an echo to echo technique instead of interface to first echo. This way, the scale will not be added to the total thickness measurement. Added gain and filtering will also be needed. If you are not familiarwith my terminology, email me and I will explain in more detail.
Good Luck,
FER
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| | | | S.V.Swamy
Engineering, - Material Testing Inspection & Quality Control
Retired from Nuclear Fuel Complex , India, Joined Feb 2001, 787 |
S.V.Swamy
Engineering, - Material Testing Inspection & Quality Control
Retired from Nuclear Fuel Complex ,
India,
Joined Feb 2001
787
| 01:40 Apr-03-2001
Re: Corrosion under scale or insulation Yes, the echo to echo method is more accurate than the interface to the echo method. In fact, if you are able to get more echoes, taking the interval from the 2nd to 4th or 5th will be much more accurate. This depends of course on the attenuation. If it heavily attenuated, we may have to do with even the interface to the first echo. : : Do you plan to access the tank wall from outside, as is the usual practice? If so, an ultrasonic thickness gauge with A-scan display will do in many cases. If the area is highly radioactive, then you will have to think of a permanently installed probe with read out from outside the area. Let me know whether you have tried this approach - Swamy
: .
: : : We are looking for a method of testing for corrosion of steel in Nuclear Waste tanks. There is a layer of scale or sludge on most of the walls, and we need a way of either using the technique without removing all of the scale(preferable), or a method of detection after it has been removed, which will cause the surface to be rough
: : .
: .
: The suggestion of using an A-Scan machine is a good one. May I add that it would be more accurate to use an echo to echo technique instead of interface to first echo. This way, the scale will not be added to the total thickness measurement. Added gain and filtering will also be needed. If you are not familiar with my terminology, email me and I will explain in more detail.
: Good Luck,
: FER
.
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