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Ukraine: Radiation-Resistant Robot To Rendezvous With Chornobyl

  • Julie Moffett

Washington, 29 April 1998 (RFE/RL) -- A U.S. scientist says an American-built robot capable of resisting enormous levels of radiation will venture inside the Chornobyl nuclear power plant in Ukraine early next year to help determine the exact extent of the damage.

Maynard Holliday, who works for the U.S. Energy Department's Lawrence Livermore National Laboratory in California, says the hi-tech robot called "Pioneer" is an ambitious effort to map Chornobyl's interior and determine the safest and most effective way to contain and clean up the nuclear mess.

The explosion that destroyed one of the four reactors at the Chornobyl nuclear power plant complex in April 1986 was the world's worst nuclear accident and spewed tons of radioactive dust and particles over much of Europe. After the explosion, the nuclear reactor was entombed in a concrete and steel sarcophagus that was intended to last for 30 years. But scientists say the sarcophagus is crumbling and if it isn't fixed soon, it may start leaking toxic material.

Holliday, who is the principle investigator of the Pioneer project, told RFE/RL that he began work on the program about four years ago when the U.S. Department of Energy, the National Aeronautics and Space Administration (NASA) and Carnegie Mellon University in the northeastern state of Pennsylvania joined forces to create a state-of-the art robot that could safely explore the damaged plant.

NASA and the Department of Energy are funding the two million dollar project. The hardware construction of the robot is being done by RedZone Robotics, a U.S. company which specializes in the clean up of nuclear and hazardous waste sites. RedZone also built robots to explore the U.S. nuclear power plant on Three Mile Island which had a meltdown in 1979.

NASA, the Department of Energy and scientists from Carnegie Mellon University will provide the software, computers, scientific expertise, and hi-tech equipment for the robot.

Holliday, who works for the Energy Department's Lawrence Livermore National Laboratory in California, says design specifications required the scientists use special components in the robot that could withstand massive levels of radiation. Shortly after the 1986 explosion, says Holliday, the Japanese and Germans sent exploratory robots to Chornobyl to help map damaged areas, but the robots were not constructed to withstand such enormous levels of radiation and failed almost immediately.

In fact, radiation levels at Chornobyl are so high, says Holliday, that even given today's technology, there are still no suits or shields that can safely protect a human who ventures inside certain areas of the plant.

Says Holliday: "We call those areas 'mission impossibles', because they are places where humans just cannot go safely without receiving a lethal dose of radiation."

But Holliday says Pioneer will be able to go where no man has yet been able to venture since the Chornobyl explosion.

Among the technical highlights of the robot -- it is about the size of a small desk and weighs approximately 454 kilograms. It will stand about 142 centimeters high and 36 centimeters wide. It is shaped like a small tractor with two rubber treads and has a maneuverable bulldozer bucket in front.

The bucket, says Holliday, will be able to remove up to 158 kilograms of debris. It is also equipped with a mechanical arm, he adds, that will be capable of deploying various sensors and picking up objects weighing a maximum of 16 kilograms.

Pioneer will also be capable of digging through concrete and other hard surfaces, using a specially-made core borer, in order to collect samples of soil and debris.

But perhaps the most important and sophisticated pieces of equipment on the robot, says Holliday, are the three color cameras, which have a super-sensitive hi-tech resolution and will allow the human operators to accurately maneuver the device from a safe distance.

Says Holliday: "The robot is what we call tele-operated, meaning it has to be controlled by humans. There is no autonomy is the system yet. So, the robot has to have a view of where it is going so the human operator can properly control it."

In order to protect its parts from the intense radiation, Holliday says scientists designed the robot to have as few electronics on board as possible. The majority of the components are located "off-board," he says, or on the control unit that stays inside a radiation-safe environment.

Holliday says those electronic components actually on board the robot are made of gallium arsenide computer silicon and are tungsten-shielded -- tungsten being a special substance which is highly resistance to radiation and not as heavy as lead.

Holliday adds that the robot also was not fitted with any rubber parts that might become embrittled by radiation, and has special lubricants that are radiation-resistant.

The robot has been designed to last indefinitely, says Holliday, as long as its components are periodically replaced. He says that most components of the robot have been designed to withstand one mega-rad (or one million rads) of radiation -- a rad being a measure of radiation exposure.

Explains Holliday: "All the components should be able to take that dose. Once the component reaches or gets near that dose, it would have to be replaced....Depending on how it's used, that dose could be accumulated over weeks, months or years."

Holliday says that so far the Ukrainians have been cooperative and enthusiastic about the project. He adds that several Ukrainian scientists will be in the U.S. in mid-May for training on the vision system of the robot -- the most sophisticated and complicated part of the project. Later in the summer, he adds, the U.S. will bring back the scientists and several more nuclear operators at the plant for additional training once Pioneer is fully assembled.

Holliday says: "Overall, we are getting good cooperation to date. I think what remains to be seen is.... how easy it will be to get the robot into the country. We are preparing the customs declarations now. The second issue will be how extensively [the Ukrainians] will use it, and how willingly they will accept our assistance in getting them to use all of the operational capabilities of the system."

Holliday says his team expects to have the robot fully assembled and ready to go by early summer. The training of Ukrainian scientists and operators should be finished by the end of the summer, he adds.

Holliday says he will likely ship Pioneer to Ukraine by the early fall, and begin the "cold-testing" -- or testing of the device in a non-radioactive environment -- by late fall or early winter.

Pioneer will most likely not have a "hot deployment" or be released inside the Chornobyl nuclear plant until early 1999, he says.

Explains Holliday: "The overriding goal is to get our Ukrainian partners comfortable with using robotics in routine operations at Chornobyl. They have yet to be exposed to a robust highly sophisticated machine that could do the things that this robot can do. So this is, I hope, a confidence-building project that would increase their confidence in using these type of systems in the future as Chornobyl is cleaned up."

Holliday says he believes the valuable data collected by Pioneer will also assist the international community in determining the safest way of cleaning up and containing the radioactive materials at Chornobyl.

Concludes Holliday: "It is our hope that the robot will be continually useful to the people who are doing this work."