This is a synopsis of an article published in Health Physics of Radiation-Generating Machines Proceedings of the 30th Midyear Topical Meeting of the Health Physics Society, San Jose, CA, Jan.1997.
A model CS-22 cyclotron built by The Cyclotron Corporation of Berkeley, CA, which had been in operation at the DOE-UCLA Laboratory of Structural Biology and Molecular Medicine since 1970, was taken out of service and decommissioned in the spring of 1994.
The cyclotron magnet and internal components had become activated over many years of use. However, rather than simply burying the machine at a disposal site, a recipient at a University in Beijing, China was found who would accept donation of the cyclotron "as is" and who would commit the effort and resources to refurbish and re-commission it as part of an isotope-producing and research facility.
The process of decommissioning, staging, and packing the cyclotron for shipment was relatively straightforward: The machine was dis-assembled and moved from UCLA to a licensed facility in Berkeley. The components of the cyclotron were all surveyed and the appropriate labels and shipping declarations completed.
However, the process of finding a freight company which would accept the cargo was extremely challenging. Finally, all of the problems were overcome and the last of the activated components of the cyclotron were on their way to Beijing.
Initial Decommissioning and Transport Off-Site
The CS-22 was decommissioned and dismantled as part of a program to refurbish and modernize the facility prior to installation of a new, self-shielded compact cyclotron to produce isotopes for medical research and clinical diagnostic nuclear medicine. The "hands-on" work of dismantling the cyclotron was done by personnel from IT Corporation under the supervision of one of the authors (F. Ramsey).
The CS-22 was then shipped by truck to a secondary staging site in Berkeley, CA, which had originally been the manufacturing and test facility for cyclotrons built by the Cyclotron Corporation. (The facility Radioactive Materials License had been maintained by CTI Cyclotron Systems, the successor to the Cyclotron Corporation.) The activated components were stored in vacant cyclotron test vaults until preparations for overseas shipment were completed.
Radiation Survey, Packing, and Transport Documentation
A complete inventory and survey of all activated components and subsystems was carried out. The most intensely activated parts, such as beam-probe tips, extractor septa, target windows, etc., had been left behind at UCLA for disposal. Less-activated parts, such as Dees, ion sources, etc. which were in good mechanical shape were surveyed and boxed for shipment.
Activation by several reaction processes, including direct proton (p,xn) and secondary, neutron-induced (n,p), (n,alpha), and (n, gamma) on copper, steel, tungsten, and aluminum, was noted and confirmed by gamma-ray spectroscopy using an NaI(Tl) detector/photomultiplier tube spectrometer in conjunction with standard isotope sources.
A semi-quantitative estimate of the amount of radioactivity present in each activated part was obtained assuming only one principal nuclide per part, measuring the exposure dose rate at a convenient distance from the source, and utilizing the well-known relationship:
D = Measured exposure doserate in roentgens per hour;
C = Number of curies in the sample, assuming a "point-like" source distribution;
E = Energy per decay of the principal nuclide, in MeV;
R = Source-detector distance measured in feet.
Only those components which had been activated by direct, proton-induced nuclear reactions had any notable external exposure dose rate. Two boxes had to be labelled with Radioactive III (yellow) labels. These boxes contained the cyclotron dees and extractor assemblies, and were tagged with transport indices of "5" and "3" respectively .
Those components which had been activated by secondary, neutron-induced reactions generally showed external dose rates which were low enough to ship in plain, unlabelled packages or as Radioactive I ("White label").
Securing an Ocean Carrier
Steamship companies are in the business of shipping--all subsidiary issues relating to Customs, Hazardous Materials Paperwork, etc. are generally left to a freight forwarder, who serves as the interface between the shipper and /or recipient and the steamship company. The freight-forwarder, in principle, takes all the worry and grief out of the process, receiving payment from commissions based on a percentage of the shipping fees charged by the steamship company.
Unfortunately, when a knotty problem comes up, it is very difficult to work collaboratively to arrive at a solution. There is simply no way to pay for all the extra work involved. In the end we had to perform essentially all the work required to facilitate the shipment. There were two interlocking problems: 1) Reluctance of most carriers to handle any cargo labled "Radioactive", and 2) Stringent regulations at ports-of-call regarding radioactive materials.
It turns out that all shipments by major steamship lines between the West Coast of the United States and Mainland China make one or more stops in Japan or Hong Kong. It may be possible to book shipment on a smaller boat which sails directly to Mainland China, but one would, in effect, have to charter the whole ship for one's self.
Many, though not all, steamship companies flatly refused to consider accepting the cargo. Of those that stepped forward to accept the cargo, all except one eventually begged out due to stated difficulties at transit ports, most notably those in Japan. The Chinese National Shipping Line COSCO had initially refused to to accept the cargo, but was eventually persuaded by the consignee to carry it, presumably in the national interest.
The CS-22 Cyclotron was crated up and packed into sea-going containers. The main magnet (23.5 metric tons) was secured to a 20 ft. "flat-rack" container. The rest of the cyclotron and its subsystems (14.2 metric tons) was loaded into a 40 ft "rag-top" container. The exposure dose rates measured at 1 m from the sides of the containers were 1 uSv/hr (0.1 mr/hr) for the flat rack and 4 uSv/hr (0.4 mr/hr) for the rag-top, respectively. Loading of the containers was done on the premises in Berkeley using a pair of large-capacity overhead cranes originally installed by the Cyclotron Corporation.
The "rag-top" container was used because the overhead crane, which was already available to us, greatly simplified the process of loading. However, the Long Beach Port authorities insisted on a closed-type container, invoking the literal wording of the International Maritime Dangerous Goods Regulations. Since the entire cargo was crated and consisted entirely of solid material that could not spill or leak, we were in compliance with the spirit of the regulations. However, we still had to resolve a substantial difference of opinion on interpretation, and eventually had to obtain a ruling from the Research and Special Projects Branch of the Department of Commerce to allow the rag-top container to be used for this cargo.
A word to the wise--use the closed-type container!
Transit through Japanese Ports
One final problem--the question of transit through Japanese ports--had not actually been resolved. The Japanese authorities indicated that, indeed, they would not permit the cargo, as configured, to stop at a Japanese port. We proposed shipping via Hong Kong as an alternative, where the transit license procedures are tedious but straightforward. This proposal was rejected for internal COSCO Company policy reasons. It had been 18 months since the CS-22 had been dismantled and packed. We finally resolved the impasse by agreeing to remove the two "hottest" crates--those with Radioactive III labels (referenced to August, 1994)--from the rag-top container and shipping them to China separately by air freight. The containers holding the CS-22 were then transported to China in January, 1996.
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