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PostPosted: Jan 23, 2015 4:47 am 
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So, this pyrometer temp sensor supposedly does 300-1000C. Imagine a floating mesh of fibers in your salt keeping a close eye on things, assuming the salt doesn't eat it alive or get clouded by radiation?

http://proceedings.spiedigitallibrary.o ... id=1381367


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PostPosted: Jan 23, 2015 3:59 pm 
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Silica has significant solubility in fluoride salt. So, likely bad performance. There's probably some fiber or other that has to be suitable though.

We've had some discussion about fiber optics in radiation field. Question is what this does to the fiber. Glasses are amorphous so no crystal to disturb, but it might still discolor to the point of failing optically.

Fiber optics are very interesting because they eliminate the need for high temp, rad resistant electrical penetrations into a fluoride fuel salt vessel. This is a major problem area otherwise.


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PostPosted: Jan 25, 2015 3:31 pm 
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Is there really a need to monitor the temperature of the salt directly?

If we know the thermal properties of the structural material, we could simply query the pipe or wall itself and use heat transport equations to back calculate the salt temperature, assuming the salt is a uniform temperature.


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PostPosted: Jan 26, 2015 4:06 am 
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Vince Hughes wrote:
Is there really a need to monitor the temperature of the salt directly?

If we know the thermal properties of the structural material, we could simply query the pipe or wall itself and use heat transport equations to back calculate the salt temperature, assuming the salt is a uniform temperature.


Its a good question. If it isn't necessary then we can put instrumentation outside the primary loop. That'd be great. Gamma thermometers can be used attached to the primary loop (just outside it).

But it may be necessary to know the temp quickly and directly, for pump control and safety pump trips. Depends on the design I guess.


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PostPosted: Jan 26, 2015 5:42 pm 
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"If we know the thermal properties of the structural material, we could simply query the pipe or wall itself and use heat transport equations to back calculate the salt temperature, assuming the salt is a uniform temperature."

How much time do you have? Temperature is a slow process to read because the thermowell temperature has to change. (thermocouples and RTDs) Measuring the temperature of a pipe gives even more process lag.

Does this fiber optic thing read temperature directly? How does it work? What property does it look at? Radiation and cameras have not been good friends in the past.


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PostPosted: Feb 16, 2015 4:15 pm 
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Are there any studies available about the measuring devices for an MSR?
Aren`t there plenty of studies about such things for fusion reactors that have as well high temperatures?

Temperatures, pressures, mass and/or volume flow, neutron density?


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PostPosted: Feb 16, 2015 11:26 pm 
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HolgerNarrog wrote:
Are there any studies available about the measuring devices for an MSR?
Aren`t there plenty of studies about such things for fusion reactors that have as well high temperatures?

Temperatures, pressures, mass and/or volume flow, neutron density?


http://www-pub.iaea.org/books/


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PostPosted: Feb 19, 2015 5:28 pm 
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ultrasound may be useful to measure the temperature and velocity of the molten salt. Doppler for velocity. Speed of sound in fluid for density measurement.
If you know the pressure in the circuit and the density you can get temperature. ultrasound thermometry. no penetrations. replaceable transducers. no sweat.


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PostPosted: Feb 22, 2015 5:41 am 
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michaelw wrote:
ultrasound may be useful to measure the temperature and velocity of the molten salt. Doppler for velocity. Speed of sound in fluid for density measurement.
If you know the pressure in the circuit and the density you can get temperature. ultrasound thermometry. no penetrations. replaceable transducers. no sweat.


That's a good idea. We know the salt density change upon temperature so measuring density would get temperature. Do you know if ultrasound equipment can stand radiation? And do you know if you can get a reliable ultrasound measurement through a reactor vessel? We've done ultrasound measurements on piping, it works well for very thick pipes even, but does it work accurately for fluid in a thick pipe?


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PostPosted: Feb 22, 2015 6:03 pm 
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Sorry I don't know if there is any literature on ultrasound transducers and radiation tolerance. Even if they are not overly tolerant to radiation the location on the exterior of the loop would make their replacement easier. Additionally, a 3 dimensional array could be used to monitor the internal structure of the reactor itself, similar to the way geologist measure the internal structure(temperature) of the planet. Resolution would be much greater with the shorter wave length of sound from the transducers. Computed tomography of the reactor vessel would allow reactor health monitoring. May allow 2 fluid reactors to be monitored for faults in inner containment vessel. Plating of internal structures could be measured. Many potential problems could be identified and monitored. I would think that you may be able to find potential radiation tolerant piezoelectric materials to fabricate transducers. If not, a transmission conduit (metal horn) could allow the transducer some stand off distance. I would talk to an engineer at GE about 3d reconstruction from ultrasound. They make really nice pictures of babies, reactor internals should be possible.


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PostPosted: Feb 22, 2015 6:24 pm 
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Quote:
And do you know if you can get a reliable ultrasound measurement through a reactor vessel? We've done ultrasound measurements on piping, it works well for very thick pipes even, but does it work accurately for fluid in a thick pipe?


All great questions. I have no answers. Industrial Ultrasound is use to examine the vessel/pipe for defects with little care for the contents. I come from a medical background and we are more interested in the internal structure. It would be interesting to add ultrasound monitoring to Dr. Petersen's test loop. You could validate ultrasound measurement of velocity and temperature against other measurement methods. Ultrasound transducers could be added to current reactors to measure their tolerance to radiation.

The following may allow imaging through the reactor wall. (in short -the metamaterial makes the metal invisible or nearly so)

Quote:
“An Anisotropic Complementary Acoustic Metamaterial for Cancelling out Aberrating Layers”

Authors: Chen Shen and Yun Jing, North Carolina State University; Jun Xu and Nicholas X. Fang, Massachusetts Institute of Technology

Published: Nov. 19 in Physical Review X (open access)

DOI: http://dx.doi.org/10.1103/PhysRevX.4.041033

Abstract: In this paper, we investigate a type of anisotropic, acoustic complementary metamaterials (CMM) and their application in restoring acoustic fields distorted by aberrating layers. The proposed quasi 2-D, non-resonant CMM consists of unit cells formed by membranes and side branches with open ends. Simultaneously anisotropic and negative density is achieved by assigning membranes facing each direction (x- and y-direction) with different thicknesses while the compressibility is tuned by the side branches. Numerical examples demonstrate that, the CMM, when placed adjacent to a strongly aberrating layer, could acoustically cancel out that aberrating layer. This leads to dramatically reduced acoustic field distortion and enhanced sound transmission, therefore virtually removing the layer in a noninvasive manner. In the example where a focused beam is studied, using the CMM, the acoustic intensity at the focus is increased from 28% to 88% of the intensity in the control case (without the aberrating layer and the CMM). The proposed acoustic CMM has a wide realm of potential applications, such as cloaking, all angle anti-reflection layers, ultrasound imaging, detection and treatment through aberrating layers.


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PostPosted: Feb 22, 2015 6:41 pm 
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The metamaterial paper created some buzz in the medical field. A properly designed metamaterial it would allow for ultrasound imaging though the skull (bone), currently not possible. Would make head trauma evaluation much easier. Put an ultrasound/metamaterial helmet on and look for any damage to the brain. No need to take to CT (ionizing radiation) or MRI(metallic body contraindications).


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