Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Ecologists spawn new use for PIT tags

06.10.2005


Radio frequency technology tracks mixer efficiency



Fishing for a way to assess mixing behavior in treatment tanks for radioactive waste, ecologists at Pacific Northwest National Laboratory came up with an innovative use of radio frequency technology previously used to track migrating fish.

But rather than swimming out to sea implanted in young steelhead and salmon, thousands of passive integrated transponder, or PIT, tags were added to a clay simulant and then whipped around in tests of air sparger and pulse jet mixer equipment in large test tanks and scaled prototypes.


This novel application of the PIT tags provided a means of assessing fluid motion without sampling. Performance results from the tests led to equipment configurations adopted for implementation, said Dean Kurath, an engineer with PNNL’s radiochemical engineering group.

The Hanford Waste Treatment Plant, currently under construction at the Department of Energy’s Hanford Site in Washington state, will be the world’s largest facility for treating highly radioactive waste. The Hanford Site stores 53 million gallons of the waste from past production of plutonium for the nation’s nuclear weapons program in 177 underground tanks.

Waste slurries of various compositions and thicknesses will be mixed in several different tanks in preparation for immobilizing the radioactive waste in glass through a process of vitrification or "glassifying." Mixing the materials will maintain homogeneity in process vessels, limit solids settling and stratification, improve heat transfer and mix in various process solutions. Mixing will also provide for the controlled release of flammable gases generated by the breakdown of organic materials in the waste slurries.

Bechtel National Inc., which is designing and building the Waste Treatment Plant for DOE, enlisted PNNL to help determine the best designs and technologies for mixing the mudlike waste that will be present in some of the approximately 20,000-gallon tanks. Technologies under consideration included pulse jet mixers, air spargers and steady jets generated by recirculation pumps.

In one test of an air sparger, 6,000 PIT tags were added to a tank filled with opaque simulant. Not much bigger than a grain of rice, the PIT tags contain an integrated circuit and an antenna encapsulated in glass. The tag is activated when it passes within range of an antenna that generates an electromagnetic signal. The signal alerts the tag to transmit its unique digital code back to the reader.

The same principle is at work in antitheft devices attached to retail merchandise in department stores and in subcutaneous ID tags for pets. But according to PNNL researcher Rich Brown, this is likely the first time PIT tags have been associated with mixing simulated radioactive waste.

As the sparger went to work mixing waste, the tags were detected using custom-made antennas housed in four vertical wells of PVC pipe placed in the tank around the central sparger. A remote-controlled motorized system moved the antennas up and down within the wells to detect passing PIT tags at varying depths in the tank.

The tags have a signal range of 3 to 4 inches. Movement of the slurry was determined by identifying individual PIT tags during multiple antenna passes. In other tests, the PIT tag antennas were placed around the outside of the vessel.

PNNL is a DOE Office of Science laboratory that solves complex problems in energy, national security, the environment and life sciences by advancing the understanding of physics, chemistry, biology and computation. PNNL employs 4,000 staff, has a $700 million annual budget, and has been managed by Ohio-based Battelle since the lab’s inception in 1965.

Judith Graybeal | EurekAlert!
Further information:
http://www.pnl.gov/news/2005/05-50.stm
http://www.pnl.gov

More articles from Ecology, The Environment and Conservation:

nachricht Dispersal of Fish Eggs by Water Birds – Just a Myth?
19.02.2018 | Universität Basel

nachricht Removing fossil fuel subsidies will not reduce CO2 emissions as much as hoped
08.02.2018 | International Institute for Applied Systems Analysis (IIASA)

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

Im Focus: Hybrid optics bring color imaging using ultrathin metalenses into focus

For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.

But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...

Im Focus: Stem cell divisions in the adult brain seen for the first time

Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.

The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...

Im Focus: Interference as a new method for cooling quantum devices

Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters

Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

'Lipid asymmetry' plays key role in activating immune cells

20.02.2018 | Life Sciences

MRI technique differentiates benign breast lesions from malignancies

20.02.2018 | Medical Engineering

Major discovery in controlling quantum states of single atoms

20.02.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>