New robot to help stabilize environment around stricken Chornobyl reactor (06/06/99)

New robot to help stabilize environment around stricken Chornobyl reactor

by Roman Woronowycz
Kyiv Press Bureau

PRYPIAT - The U.S. Department of Energy demonstrated a mobile robot here on May 17 that they hope will be able to enter the radioactively poisoned environs of the Chornobyl nuclear power plant's No. 4 reactor, which has remained sealed in a concrete sarcophagus since the reactor exploded 13 years ago.

Although not related to the Shelter Implementation Plan (SIP) signed in December 1995 by Ukraine, the European Union and the G-7 states, which lays the groundwork for sealing the quickly deteriorating outer covering, the robot is part of stepped-up activities at the Chornobyl site to finally stabilize the environment around the damaged reactor.

It is now estimated that 30 to 50 tons of radioactive materials still remain within the nuclear power plant that was the scene of the worst nuclear accident in history when it blew on April 26, 1986, sending tons of radioactive debris into the atmosphere and around the globe. The newest estimates put the amount of fissile material at nearly 10 times what was thought to exist even a couple of years ago.

It is hoped that the robot, a futuristic-looking, tracked, mechanical vehicle with radiation-resistant casing, will successfully withstand the electromagnetic and gamma rays and other radioactivity that fills the sarcophagus. Its function is to produce a three-dimensional map of the interior of the crippled reactor and its crumbling protective shell, and to take material samples of the sarcophagus walls and floors.

The developers of the vehicle, dubbed the Pioneer, claim it is the first vehicle ever developed that is able to withstand megadoses of radiation and still operate.

"Pioneer will be able to operate in work environments with radiation fields many times the lethal dose for humans," said U.S. Deputy Secretary of Energy T. J. Gaulthier, who was on hand for the demonstration held in the shadow of the crumbling reactor sarcophagus. "We are witnessing the result of years of work in a robot that has its foundations in the moon explorations."

Mr. Gaulthier was in the Chornobyl region on a good-will tour that also included a visit to two of the international laboratories in the area, whose work it is to investigate the aftereffects of the Chornobyl tragedy, and to a Slavutych city high school, where he introduced an international student program.

The three-foot-long and three-foot-high Pioneer was developed by Red Zone Robotics of Pittsburgh with funding and technical assistance from the Department of Energy, NASA, Carnegie-Mellon University, Oak Ridge Laboratory, Jet Propulsion Laboratories and Laurence Livermore Laboratory.

Pioneer is geared to generate photo-realistic 3-D images using NASA stereo technology developed for the Mars Pathfinder mission by Silicon Graphics, as well as radiological maps that will show the varying levels of radioactivity inside the sarcophagus. The robot has a 15-centimeter concrete sampling drill, a manipulating arm and a shovel to move and lift material.

But, according to some Chornobyl shelter officials, it is far from certain whether the $2 million project will succeed. One official said that other robots had been developed and tested - including one built by a Japanese team - but had not been able to withstand the harsh environment within the sarcophagus and had broken down.

Valentyn Kupnyi, director of the No. 4 reactor shelter, told reporters after the Pioneer demonstration that he would not answer any questions regarding the robot until it had been put through a series of tests by his team.

The only accolade he would give the Pioneer was to say that it was an example of the intensive and fruitful cooperation between two countries and their ministries.

Even Red Zone Robotics Vice-President Bruce Thompson indicated that he could not be sure what the future holds for the Pioneer robot at Chornobyl. "We are still working to determine when and what the first mission will be," said Mr. Thompson.

Reconstruction of the sarcophagus

Approximately $400 million of the estimated $758 million that is needed to put a new shelter around the stricken reactor has been raised, and the European Bank for Reconstruction and Development has promised to grant more money, which SIP officials hope will amount to between $120 million and 160 million in the next several months.

Mr. Kupnyi explained that, while 1998 was a year of planning and design, actual reconstruction of the crumbling sarcophagus would begin in the second part of 1999.

"In the last five months we have seen a desire on the part of the foreign investors to get down to the actual work," said Mr. Kupnyi.

The engineering and design stage of the implementation program, although slightly delayed because of organizational problems, is about halfway through its two-year planned duration.

Armand Langmo, co-director of Project Management Unit, the three-company consultant consortium consisting of Bechtel, Electricité de France and Battelle that is directing the engineering stage, said workers will soon begin one aspect of the initial phase of reconstruction to strengthen and stabilize the major beams that support the roof of the structure.

"These beams rest upon the failed structural elements that are still standing but are in a damaged condition," explained Mr. Langmo at a June 2 press conference in Kyiv. "It is urgent that we stabilize these beams so that there is not a roof collapse of the shelter."

Mr. Langmo said the threat of collapse is not immediate, but that the beams no longer meet general structural codes. While the engineers have faith that the walls of the reactor, although deteriorating, remain structurally sound, they have less faith in the beams. They most fear a natural calamity, such as an earthquake, which could cause the beams to shift and lead to a collapse of the roof.

"We decided that the B1-B2 beams were critical enough to do that first, even though we didn't have the total study on paper yet," he added.

The B1-B2 beam project is scheduled to begin in August-September and to be completed by the end of October.

The shelter reconstruction plan will not be a project that moves from one stage to another in a linear fashion, but will consist of a variety of individual projects that will be introduced in various stages to stabilize different aspects of the shelter, said Mr. Langmo.

The Shelter Implementation Plan, which has 22 planned stages, was begun in July 1998. Four bid packages have been tendered and approved by SIP authorities for work on the shelter that will include participation by companies from Japan, Germany, France, Great Britain, the United States, Russia and Ukraine. Neither Mr. Kupnyi nor Mr. Langmo would say when the reconstruction of the shelter would be complete.

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