Program Description

Overview

In April of 1986, a catastrophic nuclear accident occurred in the Chornobyl Unit 4 nuclear reactor. Shortly after the accident, an external containment structure, or Shelter (often referred to in the West as sarcophagus) was erected. Much of the Shelter's structural support is provided by the remains of the original building, the structural integrity of which was severely compromised by the accident. The Shelter itself is showing signs of deterioration and its own integrity is dubious. For remediation of Unit to 4 proceed with minimal risk to the external environment, it essential that is the Shelter be structurally sound throughout all cleanup operations.

post-accident cross section of the Unit 4 reactor building
 

Objectives

This program will develop and deploy a telerobotic structural diagnostic system consisting of a radiation hardened remote delivery platform and characterization tools capable of performing a significant structural evaluation and monitoring mission within the Chornobyl Unit-4 Shelter. Initial deployment will be in a relatively benign portion of the Shelter to demonstrate in-field capabilities. These proving missions will be followed by entries into areas that pose significant challenges in the form of rugged terrain, high radiation, and complete darkness. The robot, dubbed Pioneer, will initially deploy devices to map radiation, temperature and humidity; acquire core samples of concrete structures for subsequent engineering analysis; and make photo-realistic three-dimensional maps of the building interior. 

Schedule

In the first phase of the project, operating scenarios, functional requirements and conceptual designs for the integrated robot and its subsystems were developed in concert with the Shelter operators and the Ukrainian National Academy of Sciences. Phase II consists of detailed design, fabrication and integration , and a documented factory acceptance test took placein Pittsburgh in November, 1998. In Phase III, all hardware was shipped to the Shelter. Installation of the system in a local testing facility, training of Ukrainian operators and cold testing are now in progress.  

Partners and Roles

The Department of Energy's International Nuclear Safety Program initiated the development program and is responsible for definition of the application scenarios. DOE employees of Pacific Northwest National Laboratory and Lawrence Livermore National Laboratory are responsible for technical oversight. RedZone Robotics, Inc., is developing the Pioneer robot and its control unit. NREC will develop the core sampling unit; NASA's Jet Propulsion Laboratory is adding force/torque sensing and control to that device, as well as data on the drill's response to coring various materials. NREC and NASA Ames (also in collaboration with the University of Iowa) are developing the photo-realistic 3D mapping capability. Westinghouse Corporation's Science and TechnologyCenter is developingradiation, temperature and humidity sensing capabilities.