NEWS | JUNE 2021


PAR SYSTEMS ROBOCRANE AIDS CLEANUP OF CHERNOBYL, 35 YEARS AFTER DISASTER


Confinement (NSC) structure. The arch-shaped NSC, nicknamed


the “Mega Tomb,” stands 110m (361ft) tall, 165m (541 ft) long and 257m (843ft) wide. Designed to last at least a century, the shelter isolates the clean-up of the hazardous reactor area. Experts predict the site will not be completely dismantled until 2065. The RoboCrane design, incorporated


R Credit: European Bank for Reconstruction and Development T


his year marks 35 years since the Chernobyl Nuclear Power Plant disaster and five years since the New


Safe Confinement (NSC) was built, an arch-shaped shelter to confine the radioactive material at Chernobyl Unit Four, protecting the existing temporary object shelter (sarcophagus) from weather damage, and to enable the decommissioning of the unit. The workhorse of the remediation


effort is a computer-controlled, RoboCrane-inspired platform created by PaR Systems, based in Minnesota, that licensed the technology from the U.S National Institute of Standards and Technology (NIST) in 2010. Called TensileTruss, the platform is suspended from a bridge crane-and- trolley system that spans the entire NSC structure.


“The first order of business is dismantling the original sarcophagus, so the TensileTruss system will be used to sever welds, cut concrete and lift away materials for disposal,” said Rob Owen, senior program manager, PaR Systems. “Next, the mobile platform and its attached tools, such as jackhammers and blow torches, will assist in the removal of the destroyed reactor building. Finally, our system will be highly involved in the Chernobyl remediation’s most challenging task— removal and disposal of the highly


radioactive fuel debris in the reactor’s melted core.” The Chernobyl accident in 1986 was


the result of a flawed reactor design operated by inadequately trained personnel. The disaster shot a plume of highly radioactive materials into the atmosphere and led to nearly 340,000 people being evacuated from the area. Two Chernobyl plant workers died


due to the explosion on the night of the accident, and a further 28 people died within a few weeks as a result of acute radiation syndrome. The International Atomic Energy


Association and the World Health Organization estimate 4,000 cancer deaths since that date may be attributable to the radiation released. A few weeks after the accident, the destroyed reactor was covered by a quickly built concrete and steel “sarcophagus.” Then in 1997, the G-7 nations, the European Commission and the Ukraine government began a program to convert the disaster site into an environmentally safe zone. More than 40 governments committed more than $1.5bn, along with $600m from the European Bank for Reconstruction and Development, for the cornerstone of the remediation plan, a significantly more stable containment facility known as the New Safe


P Credit: Chernobyl Nuclear Power Plant www.hoistmagazine.com | June 2021 | 15


in TensileTruss, was developed in the early 1990s by NIST engineer and robotics expert James Albus, who expanded on the principle of the Stewart platform used in aircraft flight simulators. That device uses three pairs of hydraulic jacks to move a platform with six degrees of freedom (x-, y- and z-axes, along with roll, pitch and yaw). What Albus did was turn the Stewart platform upside down, manipulating it from above using motor-driven winches rather than from below with jacks. Because of this innovation, RoboCrane


lifts five times its own weight, suspends a platform much further than possible with hydraulics, holds loads rigidly in place even at an angle, and provides a precision-controlled base for remote operation of various attachments. For its long-term duties at Chernobyl, PaR Systems will affix a variety of interchangeable, remotely operated tools, including a robotic arm, drill, jack hammer, high-powered vacuum system and closed-circuit television system. ●


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