Archive for March, 2012

Radioaactive Borders (part 5)

March 18, 2012

 

Tales from the Nuclear Age

Copyright © 2012 by Charles Glassmire

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Mar. 18, 2012

Radioactive Borders (part 5)

          Six months have passed.  Radioactive Shipping Container number 307703 has been moved to a remote unused area of the Voltri docks at Genoa. It is now surrounded by a triple high stack of cement-filled shipping containers, hopefully absorbing the deadly gamma  radiation field at the surface, and allowing radiation to escape harmlessly into the sky while shielding human workers on the docks.

          The Genoa officialdom are at a loss as to how to proceed (1) . Saudi Arabia has refused to take back the shipment. The United Arab Emirates also denies any responsibility. In addition, all shipping lines are refusing to accept the container, now known to contain a large radioactive amount of Cobalt 60 isotope – source still unknown. Officials ineffectually post signs around the area saying “Danger-Ionizing Radiation”.

          One full year now passes while port officials and Italian Interior Ministry officials argue about who is responsible. The container now sits quietly undisturbed, awaiting its fate. A cost estimate indicates that the disposal operation would probably involve robots and is estimated to cost in excess of 536,000 Euro’s (~$700,000 (1) U.S.).

          A German firm is located (1)   which professes to possess the knowledge and equipment, hot cells, remote handling arms etc. to receive and handle the high intensity gamma source – assuming it is conventional structure and in one solid piece, not dispersed into a dirty bomb architecture. In addition, this company routinely recycles and reclaims commercial high intensity source materials. A plan begins to form with advice from the Germans. A team of robot operators are located with equipment able to function in a high radiation field; lastly the Genoa Port Authority and Officials of the Italian Interior Ministry finally agree to split the costs.

          On 18 July 2011 the operation begins, and it opens in le grande style; five large green tents are pitched in the area and are badly needed. Now assembled near the remote dock are a Genoa Police bomb squad, a robot team complete with assorted devices, the original Port Authority Radiation Team (with Geiger counters at the ready), dock workers to operate a large crane, assorted officials from Police, Genoa Port Authority and the Italian Ministry of the Interior, one small sized ambulance, and – ten fire trucks accompanied by some 40 firemen!

          The possibility of a dirty bomb inside the container is very real and must be dealt with. The container rear doors cannot be opened because they may be wired to explode the device. Operating from a distance, a crane is used to lower a cutting machine onto the container roof. A foot wide hole is cut into the roof to allow access. Now a small robot is lowered onto the roof with cameras attached. The hole is sniffed for traces of explosives with negative results. But this is not definitive. A small fiber optic camera and light wire is inserted and searches the maze of radiators and scrap copper wire packed into the interior. No wires can be detected around the doors, nevertheless authorities are reluctant to open the doors.

          Now the fire department cuts a larger access hole into the roof and the really difficult search begins. If it is a commercial source, the search must find a 9 inch long pencil-thin piece of metal lying among some 20 tons of scrap! An excavator machine is used to pick up a few cubic feet(1) of metal in its claw. The sample is moved away to a safe distance, and a radiation crew checks the debris for gamma rays. Nothing is found. For three long days this sampling method continues, removing claws-full at a time to be tested with negative results. The only positive note is that the source is probably not dispersed in powder form throughout the container, since no radiation clings to the sampled debris.

          Radiation detectors are placed on the container roof to detect as the metal is lifted from the hole. Finally on the morning of the 26th of July, as the claw lifts a load clear of the roof the radiation detectors sing out. They have finally grabbed onto the source! As the claw is raised into the air part of the load slips back into the hole. Again the detectors alarm as the metal falls back inside. The operator tries again and seizes a second clawfull. This time the pile slips onto the ground outside the container.

          Now a tracked robot is sent in to photograph the pile of debris. Night is falling and it takes another 10 hours of carefully examining robot video pictures to locate the pencil buried in the pile. Near midnight, the robot raises aloft a Cobalt pencil held securely in its gripper! Curiously the source is painted with copper paint making it harder to single out from the other metal debris. Has someone intentionally tried to disguise the material to look like scrap?

          Now that the robot has the source isolated in its gripper, it is necessary to put it into a configuration safe to legally transport. In the U.S. the transport of radioactive materials is heavily regulated by state and local municipalities. The transport vehicle must be marked with the yellow and magenta radiation danger signs front and rear. Documentation must be carried indicating the isotope and activity level (using a unit called “Curies”). Lead containers known in the trade as “pigs” are used to shield the material, and must be safety tested to remain intact against fire and crash conditions. The pigs which contain gamma radiation are often 6 to 10 inches in wall thickness, making a container extremely heavy to lift.

          A search is on for a suitable pig. One is located nearby, but when the robot places the pencil source into the hole in the center of the pig, several inches protrude above the top of the opening, prohibiting use of this pig for shipping. A new pig must be machined in a metal shop – this will take two more days!

          Meanwhile the pencil is examined for identifying marks. None are found. There is no indication where it was manufactured and how or why it was inserted into the container. It appears to be a Cobalt 60 source configured for use in medical therapy irradiation. It is an expensive proposition to dispose of these sources by legal means and it is speculated someone may be trying to save costs of disposal.

          Finally on July 29, 2011, the source is sealed into a suitable (new) pig, and levels outside the container once again return to background. The pig is secured to the back of a flatbed truck, and documentation is prepared to ship it to Leipzig where it will be recycled into a new medical irradiator. Life at the Voltri Terminal now returns to some semblance of normality, and the Italian Sun sets upon a Genoa dock preparing to accept its daily quota of thousands of new offloaded shipping containers, contents unknown.

(to be continued …)

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(1) “Mystery Box”, Andrew Curry, Wired Magazine, Nov. 2011.