A pair of autonomous robots developed
by Carnegie Mellon University's Robotics Institute will soon be driving through
miles of pipes at the U.S. Department of Energy's former uranium enrichment
plant in Piketon, Ohio, to identify uranium deposits on pipe walls.
The
CMU robot has demonstrated it can measure radiation levels more accurately from
inside the pipe than is possible with external techniques. In addition to
savings in labor costs, its use significantly reduces hazards to workers who
otherwise must perform external measurements by hand, garbed in protective gear
and using lifts or scaffolding to reach elevated pipes.
DOE
officials estimate the robots could save tens of millions of dollars in
completing the characterization of uranium deposits at the Portsmouth Gaseous
Diffusion Plant in Piketon, and save perhaps $50 million at a similar uranium
enrichment plant in Paducah, Kentucky.
"This
will transform the way measurements of uranium deposits are made from now
on," predicted William "Red" Whittaker, robotics professor and
director of the Field Robotics Center.
Heather
Jones, senior project scientist will present two technical papers about the
robot on Wednesday at the Waste Management Conference in Phoenix, Arizona. CMU
also will be demonstrating a prototype of the robot during the conference.
CMU
is building two of the robots, called RadPiper, and will deliver the production
prototype units to DOE's sprawling 3,778-acre Portsmouth site in May. RadPiper
employs a new "disc-collimated" radiation sensor invented at CMU. The
CMU team, led by Whittaker, began the project last year. The team worked
closely with DOE and Fluor-BWXT Portsmouth, the decommissioning contractor, to
build a prototype on a tight schedule and test it at Portsmouth last fall.
Shuttered
since 2000, the plant began operations in 1954 and produced enriched uranium,
including weapons-grade uranium. With 10.6 million square feet of floor space,
it is DOE's largest facility under roof, with three large buildings containing
enrichment process equipment that span the size of 158 football fields. The
process buildings contain more than 75 miles of process pipe.
Finding
the uranium deposits, necessary before DOE decontaminates, decommissions and
demolishes the facility, is a herculean task. In the first process building,
human crews over the past three years have performed more than 1.4 million
measurements of process piping and components manually and are close to
declaring the building "cold and dark."
"With
more than 15 miles of piping to be characterized in the next process building,
there is a need to seek a smarter method," said Rodrigo V. Rimando, Jr.,
director of technology development for DOE's Office of Environmental
Management. "We anticipate a labor savings on the order of an eight-to-one
ratio for the piping accomplished by RadPiper." Even with RadPiper,
nuclear deposits must be identified manually in some components.
RadPiper
will operate initially in pipes measuring 30 inches and 42 inches in diameter
and will characterize radiation levels in each foot-long segment of pipe. Those
segments with potentially hazardous amounts of uranium-235, the fissile isotope
of uranium used in nuclear reactors and weapons, will be removed and
decontaminated. The vast majority of the plant's piping will remain in place
and will be demolished safely along with the rest of the facility.
The
tetherless robot moves through the pipe at a steady pace atop a pair of
flexible tracks. Though the pipe is in straight sections, the autonomous robot
is equipped with a lidar and a fisheye camera to detect obstructions ahead,
such as closed valves, Jones said. After completing a run of pipe, the robot
automatically returns to its launch point. Integrated data analysis and report
generation frees nuclear analysts from time-consuming calculations and makes
reports available the same day.
The
robot's disc-collimated sensing instrument uses a standard sodium iodide sensor
to count gamma rays. The sensor is positioned between two large lead discs. The
lead discs block gamma rays from uranium deposits that lie beyond the one-foot
section of pipe that is being characterized at any given time. Whittaker said
CMU is seeking a patent on the instrument.
The
Robotics Institute and Whittaker have extensive experience with robots in
nuclear facilities, including the design and construction of robots to aid with
the cleanup of the damaged Three Mile Island reactor building in Pennsylvania
and the crippled Chernobyl reactor in Ukraine.
DOE
has paid CMU $1.4 million to develop the robots as part of what CMU calls the
Pipe Crawling Activity Measurement System.
In
addition to the Portsmouth and Paducah plants, robots could be useful elsewhere
in DOE's defense nuclear cleanup program, which is not even half complete,
Rimando said. Other sites where robots might be used are the Savannah River
Site in Aiken, South Carolina, and the Hanford Site in Richland, Washington.
"With
at least 50 more years of nuclear cleanup to be performed, the Robotics
Institute could serve as a major pipeline of roboticists for DOE's next several
workforce generations," he added.
https://www.sciencedaily.com/releases/2018/03/180320084315.htm
