In Oak Ridge firm may soon be manufacturing and marketing an ORNL-developed robot that can easily inspect pipes for leaks, obstructions, and corrosion. Martin Marietta Energy Systems, Inc., has signed a licensing agreement that grants commercial rights to the patented robotics technology to REMOTEC, Inc., a robotics manufacturer based in Oak Ridge.

Don Box, a development engineer in ORNL's Chemical Technology Division, invented a robot now called Pneu-worm that can more easily move around the insides of pipelines, tanks, and other tight places that require inspection. REMOTEC officials say the robot's design and action offers unprecedented inspection capabilities for difficult-to-access areas.

Common to industrial plants and municipalities are thousands of feet of pipeline that periodically requires inspection. The ducts of commercial air-conditioning systems are also subject to inspection, but like many pipelines, they may be too small to accommodate workers.

View a video clip on the PNEU-WORM (QuickTime, 1.2 minutes, 2.2 MB).

Box has considerable experience inspecting pipelines and underground tanks at the Laboratory. Realizing that existing robots as well as humans have problems maneuvering in these cramped areas, he invented the new robot.

"Traditional robots with wheels or tank-like tracks can't climb vertically oriented pipes or make sharp turns," Box explains. "Pneu-worm does so with dexterity that is amazingly true to its namesake."

Its "head" and "tail" are metal disks, each fitted with an inflatable bladder around its circumference like an inner tube on a bicycle wheel. Three flexible rubber hoses that act as bellows connect the disks and serve as the Inchworm's "body." Two inexpensive pumps provide air pressure and vacuum to the bladders and hoses. Air lines are bound together in a single umbilical cord that trails the unit as it explores pipelines.

For the unit to go forward, the tail bladder is pressurized so it expands to grip the wall of the pipe while the head bladder remains deflated. When air pressure is applied to the three connecting "body" hoses, the head is pushed forward (or upward) through the pipe. Next, the head bladder is inflated to grip the pipe, the tail bladder is deflated to release its grip, and the hoses are vacuumed, drawing the tail forward.

Repeating this sequence sends the robot crawling through the pipe in a motion reminiscent of an inchworm. To make a 90-degree turn, two of the "body" hoses are vacuumed while the third is pressurized, causing the device to turn in the direction of the vacuumed hoses.

Box's demonstration model is about 0.3 meters (1 foot) long and 10 centimeters (4 inches) in diameter. It moves through pipes at a rate of about 9 meters (30 feet) per minute.

Tiny lights and a miniature high-definition camera in the robot's headpiece allow the operator to monitor what's ahead in the pipeline and to easily spot leaks, obstructions, or corrosion. Pneu-worm can be operated using switches that control each function, or it can take commands from joystick-controlled computer software.

"And there are many possibilities with regard to what can be added to the unit based on specific needs," Box said. For instance, sensors can be added to detect the properties of liquids or air in a pipeline, and added tubing or collection scoops can be used to draw samples for laboratory analysis."

John White, REMOTEC's founder and president, calls the partnership with Energy Systems a perfect match. "We know there's a market for Pneu-worm," he says. "It's very cleverly designed, it's been patented, and we're in the business of robots," he says. REMOTEC officials said they foresee an increase in employment to make production of the Pneu-worm robot possible. They expect to add personnel for marketing and production and for field representatives.

REMOTEC robots were used to gather unexploded ordnance following Operation Desert Storm and are popular among many big-city police departments for use with bomb squads and hostage crises. REMOTEC is a subsidiary of Westinghouse Electric Corporation.

The first commercial uses for PNEU-WORM, says REMOTEC Vice President Howard Harvey, may be for inspecting pipelines at nuclear power plants. "But any other type of pipeline is applicable," he says. "We have several ideas for making it even more universal."

The robot was even used by ORNL environmental scientists to explore abandoned kingfisher nests. Kingfishers are birds that build their nests in muddy river banks. The invention earned Box the 1992 International Inventor's Forum Award for robotics.--Wayne Scarbrough

Radon Detectors Sense Uranium Contamination

Like fleas on a dog, uranium and plutonium can be present on a surface and yet be difficult to detect. These hazardous elements can lurk on irregular surfaces, in wall cracks and crevices between floor tiles, inside pipes and tubes, under tight-fitting furnishings, and at or below soil surfaces.

At ORNL researchers are modifying and evaluating commercially available radon detectors for use in mapping uranium and plutonium concentrations in soils and on building surfaces, such as floors, ceilings, walls, and window ledges.

"Use of these detectors is being evaluated as a potential low-cost alternative to conventional radiation surveys," says Richard Gammage, who is leading the effort at ORNL. The work is being done under cooperative research and development agreements (CRADAs) between Martin Marietta Energy Systems, Inc., and two manufacturers of different types of radon detectors.

The two CRADAs involve personnel from the Measurement Systems Research Group (led by Gammage) in ORNL's Health Sciences Research Division. The two manufacturers of two different types of radon detectors are Rad Elec, Inc., of Frederick, Maryland, manufacturer of electret ionization chambers, and Landauer, Inc., of Glenwood, Illinois, manufacturer of alpha-track detectors.

CRADAs are designed to foster cooperative research between industry and government laboratories by offering private firms advantageous rights to patents and other intellectual property from the joint research, trade-secret-like protection of joint data, and streamlined government approval of the agreement. The chief goal of CRADAs is to improve the nation's competitive position in the world marketplace.

One approach to detecting radioactive contamination in inaccessible places is to use commercial plastic detectors of indoor radon. Available as disks or thin sheets that can easily be held between the index finger and thumb, they are inexpensive, simple, and able to detect alpha particles, the radiation given off by the decay products of radon as well as by fissionable uranium and plutonium. Detectors made of thin plastic sheets are particularly attractive because they can be cut into pieces of various sizes and shapes to make them fit into tight or inaccessible places.

Rad Elec's electret ionization chamber operates on the principle that ions are formed in air by the presence of alpha particles. The device consists of a disk of charged Teflon attached to a chamber made of conducting plastic, creating a simple, passive ionization chamber. The static charge on the electret detector attracts the negatively charged ions generated by alpha particles entering the chamber volume. The collected ions reduce the disk surface charge.

The change in the disk surface charge before and after the detector was deployed is determined by comparing surface voltage measurements using a hand-held electrometer. Because the voltage change is proportional to the number of alpha particles in the chamber volume during the exposure time, it indicates the concentration of surface alpha emitters in that location.

Gammage, Kevin Meyer, Charles Dudney, and other ORNL researchers have shown that a number of Rad Elec's electret ionization chambers deployed on a large site can be used to generate a map of relative uranium contamination in soil. They demonstrated this capability recently on a field 240 meters by 540 meters that is contaminated with low levels of uranium at the Fernald Environmental Management Project in Ohio. Similar demonstrations have been carried out at a Nevada Test Site area that is contaminated with isotopes of plutonium and americium. The purposes of these in situ measurements are to demonstrate the field screening capabilities of plastic radon detectors at contaminated sites and to verify the effectiveness of remediation efforts.

The ORNL researchers also have tested alpha-track detectors made by Landauer, Inc., for measuring uranium and plutonium concentrations in soils and on building surfaces. Each detector consists of a clear plastic sheet about 1 millimeter thick. When struck by alpha particles, localized microscopic damage forms in the crystalline structure of the plastic. When etched in an appropriate caustic solution, these defects in the chemical bonds, or tracks, become visible as etch pits. These pits can be counted under an optical microscope for use in calculating alpha particle track density.

Such alpha-track detectors can be cut or formed to suit a particular use. In 1993 at the Nevada Test Site, ORNL researchers drove wooden stakes into the ground, forming narrow holes 20 centimeters (8 inches) deep. Then they inserted long narrow strips of the plastic material into the holes to obtain a depth profile of plutonium contamination before cleanup. The same procedure will be used after cleanup to verify that the plutonium levels have been reduced to environmentally acceptable levels.

These detectors were also used to measure transuranic contamination along narrow ledges and in crevices between vinyl floor tiles under a glove box at ORNL. By using a computer to plot the number of damage tracks on three-dimensional graphs, the ORNL researchers could pinpoint the most radioactive spots in these inaccessible places (see graphs above).

In addition to soils, floor tiles, outdoor loading docks and other concrete areas, ORNL researchers will be testing alpha-track detectors for measuring alpha contamination at the Oak Ridge K-25 Site, particularly in less accessible areas such as piping; valves; diffusers; gas compressors; and electrical, ventilation, and cooling systems. Targets for measurement at ORNL will include the Molten Salt Reactor and the storage tanks and transfer canal of the Graphite Reactor. It is hoped that this simple approach will "sniff" out hidden radioactive contamination more effectively than combing a dog's fur for fleas.--Carolyn Krause

Frozen Gas Pellet Blasting Licensed

An ORNL scientist who developed a technology for refueling experimental fusion energy devices and then adapted it for cleaning surfaces has received the right to manufacture and sell it for profit.

Energy Systems has signed a licensing agreement with Cryogenic Applications F, Inc., of Clinton, Tennessee, whose president is ORNL's Christopher A. Foster. The Clinton company has been granted the right to further develop and market an environmentally safe ORNL technology for surface cleaning. Specifically, it will be used to remove paint and radioactive contamination from surfaces by blasting them with pellets of frozen gases. The cleaning technology may replace the practice of washing parts with chlorine-containing solvents, which pollute groundwater and destroy Earth's protective ozone layer.

ORNL scientists Foster and Paul Fisher developed the cryoblasting process in conjunction with the Y-12 Plant. They are conducting a project for the U.S. Air Force at the Warner Robins Air Logistics Center (at Robins Air Force Base in Georgia) to develop a robot-compatible cryoblaster for stripping paint from military aircraft. Paint is removed so metal parts can be inspected for cracks and corrosion to determine if they can be placed back into service. As staff scientists with ORNL's Fusion Energy Division, Foster and Fisher hope to demonstrate to the Air Force that their cryoblasting process for stripping paint from aircraft is potentially faster, more efficient, and cleaner than other techniques.

A nonexclusive patent license agreement has also been made with Alpheus Cleaning Technologies Corporation of Rancho Cucamonga, California, for commercial use of the cryoblasting process technologies.

The licensed technologies include a method of freezing carbon dioxide and argon gases into pellets and a pellet-blasting centrifugal accelerator with an improved rotor and housing. Foster originally developed a centrifugal accelerator to fire pellets of frozen hydrogen gases (deuterium and tritium) into hydrogen plasmas to refuel fusion devices. One such centrifugal injector, which uses a high-speed wheel to accelerate the frozen pellets before injecting them into the plasma center, is used to refuel the Tore Supra tokamak in France.

"The advantage of the cryoblasting technique over conventional techniques for cleaning surfaces is that it does not leave a waste stream requiring additional cleanup," Foster says. "In cryoblasting, the frozen pellets evaporate into harmless gases, and the contaminants freed from the surface can be sucked from the air by vacuum systems with high-efficiency particulate absorbent filters."

The usual procedure for removing aircraft paint has been to bathe the planes in methylene chloride. Because use of this solvent is being discouraged by the Environmental Protection Agency, ORNL-developed centrifugal technology for blasting carbon dioxide, or dry ice, pellets may be useful to the Air Force and similar customers.

"A paint-stripping technology that uses compressed air to propel dry ice pellets is on the market," Foster says. "But our technology strips paint at a higher rate."

Cryoblasting also may replace sandblasting because it doesn't leave a sand-contaminated waste stream. At the Y-12 Plant, cryoblasting using argon pellets is being developed as a replacement for iron-bead blasting for removing oxides from metal surfaces. Because it is inert, argon will not react with reactive metals. Unlike the iron beads, the argon pellets evaporate into the air and do not add to the solid waste stream.

Larry Dickens of Energy Systems' Office of Technology Transfer negotiated the nonexclusive patent license agreement with Cryogenic Applications F.

Lessons Learned from SEMATECH Project

ORNL researchers have helped forge a tool for etching circuits on computer chips in collabo-ration with researchers from the University of Cincinnati (UC) and SEMATECH, a nationwide technology consortium of 11 semiconductor manufacturing companies headquartered in Austin, Texas. Development of the tool has resulted in improvements in two companies' products and provided valuable lessons, including an understanding of why no U.S.-manufactured etch tool based on this work is on the market.

The purpose of this project was to help continue the astounding advances in performance and capability of digital electronic systems and the very large-scale integrated circuits on which they depend. As a result of these advances, integrated circuits have become, in turn, large scale, very large scale, and now even ultralarge scale. Increasing numbers of circuits are being built into silicon chips, making computers more compact, faster, and able to store greater amounts of information.

For example, the 8-megahertz, 16-bit systems with 64-kilobyte memory chips in Apple Macintosh computers of the early 1980s have been replaced by 40-megahertz, 32-bit systems with 4-megabyte chips. The pace of this advance is expected to continue for at least another decade.

At the heart of this revolution is the ability to economically manufacture the devices that make up these complex circuits in ever-smaller dimensions. The transistors in today's integrated circuits measure 0.5 to 1 micron (millionth of a meter), but the goal is to reduce those dimensions to less than a quarter micron—smaller than the wavelength of blue light. Because tools that can produce these small dimensions do not exist, they must be developed to turn 8-inch wafers of silicon into tens of billions of transistors.

ORNL recently completed the first of several projects that are contributing to the development of needed processes and tools for manufacturing microchips. Researchers working in semiconductor manufacturing are in the Fusion Energy, Solid State, and Instrumentation and Controls divisions, among others. Their task is to work with the semiconductor industry to help the United States become more competitive in the world market for computer chips.

The first project, begun in 1989 with SEMATECH and UC, was announced in an Oak Ridge ceremony in which the late Robert Noyce, co-inventor of the microchip and then SEMATECH chief executive officer, presented then Senator Albert Gore, Jr. (now vice president of the United States) with one of the first silicon wafers produced by SEMATECH. The project began after SEMATECH approached ORNL and UC with a proposal to combine the organizations' expertise to produce a silicon etch tool that could create circuit devices as small as a third of a micron.

ORNL's Fusion Energy Division had long been developing and using electron cyclotron resonance (ECR) heating for producing and heating plasmas in magnetic fusion devices. In 1987, in conjunction with the Solid State Division, it had begun a project supported by the Director's R&D Fund to adapt this technology to deposition of thin films. Tom Mantei of UC had also been applying this technique to materials processing.

Mantei, SEMATECH researchers, Lee Berry of ORNL's Fusion Energy Division, and Steve Gorbatkin of ORNL's Solid State Division worked together for two years on this project. In that time they developed a tool for heating and controlling plasmas (ions and electrons in a hot gas) to etch circuits in silicon wafers. They and their SEMATECH colleagues assembled three processing systems, each worth about $500,000; evaluated three different systems configurations; and in their research produced etch results that were competitive with the world's best. However, the project was unsuccessful in getting an American vendor to use the research results to develop a commercial chip-processing tool.

The project did have commercial success from the standpoint of two small businesses that were involved in it. ASTeX of Woburn, Massachusetts, supplied the microwave, magnet, and plasma chamber components for the research etch tool, and Plasma Quest of Richardson, Texas, added controls, wafer handling, and vacuum and process gas systems. Both companies are selling components and systems that have been improved as a result of the project's research.

The project also has had technological success in that its results have been used by Berry, Gorbatkin, Gary Henkel, Rob Rhoades, and others in the Solid State and Fusion Energy divisions in their work with IBM under a cooperative research and development agreement (CRADA). The goal of this CRADA is to find ways to deposit conducting films that connect devices in an integrated circuit.

What lessons have been learned from the SEMATECH project? According to Berry, "First, we learned that meeting a schedule is more important in the commercial world than in the research world. Unless we got our results out in time for a U.S. vendor to get a product on the market before its competitors, the market for our product would likely be lost. The drive to meet real objectives on time sparked a spirited effort by the industry-laboratory-university team that may have resembled the way it was in the old Manhattan Project days at Oak Ridge."

Second, research priorities were focused on a marketable product. "We expected that research on interesting problems that did not move the project forward was inappropriate," Berry says. "We did very little work in areas that would have improved our ability to develop successive generations of etch tools. The surprise was that taking risks in the hope of improving the schedule was encouraged."

Gorbatkin notes that the approach to experimentation was different in the project than it is in many research studies. "Often, variables are systematically manipulated individually, with all others held constant, to gain an understanding of a physical process," he says. "In the SEMATECH project, we conducted experiments in which more than one variable changed from run to run. A statistical approach was emphasized in determining the most efficient method of achieving the desired results. To guide us, a statistician was assigned to the project, and we were given courses in experiment design and analysis. Industry may well be the leader in the use of systematic, statistically based, experimental techniques."

The third lesson, Berry says, is the importance of industry pull--recognizing a need for a product and choosing the technology that will make the product competitive. "It was unanimously agreed by U.S. semiconductor companies that advanced etch technology is needed," he explains, "but it was not agreed that the etch tool should be based on ECR technology. Foreign companies were already introducing ECR tools, and, even if a U.S. tool could be produced and put on the market at about the same time, it would look too much like the foreign products to have a competitive edge. Thus, U.S. companies adopted the strategy of developing an etch tool based on a different technology--inductively driven plasma sources--instead of commercializing the ECR technology developed in the SEMATECH project."

What did industry learn from ORNL? "We believe we demonstrated that we could successfully work as a team with industry and university collaborators in a tightly focused, applied project," Gorbatkin says. "Our work maintained a high standard of excellence and drew on a broad range of skills from across the Laboratory. This belief is validated by current ORNL projects in semiconductor manufacturing."

ORNL in CRADA with General Motors

Energy Systems, Inc., has entered into a CRADA with the AC Rochester Division of General Motors Corporation to improve vehicle emission-control catalysts and systems for conventional and alternative-fuel vehicles.

Researchers at ORNL will develop materials and manufacturing processes that will help General Motors meet more stringent emission standards requiring improved catalyst efficiency and longer usage.

Under the joint agreement, emission-control catalysts and systems will be developed to help General Motors further improve vehicle fuel economy and alternative fuel capabilities, making the United States less dependent upon foreign oil.

Another objective of the agreement is to reduce the company's use of precious metals such as platinum, palladium, and rhodium, which also should reduce dependence on foreign sources.

Researchers will use sophisticated spectrographic techniques to study mechanisms that cause emission-control catalysts to become ineffective. ORNL engineers will conduct tests to evaluate new catalysts using flow reactors and multicylinder engines and exhaust systems that include catalytic converters provided by AC Rochester. Engines already have been sent to Oak Ridge by General Motors. Final road tests will be performed by General Motors.

AC Rochester is the world's largest manufacturer of automotive catalytic converters, and ORNL has a strong reputation in materials research, coupled with engineering research experience in automotive fuels and engines.

The CRADA, which is expected to achieve desired results by October 1995, is being funded by DOE's Office of Industrial Technologies, Advanced Industrial Concepts Division, and the Office of Transportation Technologies. 

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