They then moved on to discuss practical matters. Each movement was asked to contribute one million Euros to the joint fund and to try to get hold of as many gamma radiation sources as possible. Ollie directed them to the prime locations where such sources could be found — mainly hospitals that performed radiation therapy and industrial facilities that used such sources to test pipe welds or measure the level of liquids in closed holding tanks. He told them that the sealed sources were safe but heavy because of the protective shielding. If they did not care about the safety of the people handling and transporting the sources, and if removing a heavily shielded source was impossible, then the bare sources could be taken, risking external radiation exposure to the people close to them. In order to keep the location of the laboratory secret all stolen sources were to be brought to an address in Milan and from there they would be taken to the clandestine laboratory by the two drivers who knew its exact location. Goals were set for each participant according to the technological development of their country, their access to the sources and the number of trustworthy members. A cover story was established claiming that the radioactive materials would be used to make a radioactive dispersion device known in short as RDD or to public as a "dirty bomb". This would seem plausible enough for the underground movements and yet make them aware of the necessity of keeping the activity in secret.
Ollie suggested that the joint venture receive the codename Astraea after the mythological goddess of innocence and purity that was often also associated with justice and this was supported enthusiastically by the Greek Golden Dawn faction and accepted by the other members.
Professor Modena, with the help of Ollie and a few handpicked technically skilled people from the European countries that participated in the project, started acquiring the equipment needed for the laboratory and moving the personnel and materials to the vicinity of the famous Botanical Gardens of Padova. They rented a warehouse with a large deep basement and they converted the street level floor into offices that served as the front of the high-tech company they named Astraea. It was presented as a research and development company involved in innovative industrial chemical processing.
On the first floor level they constructed a small dormitory and rigged a couple of bathrooms to serve as the lodging of the small workforce. They also converted some space into a kitchen and dining area as they did not want to be seen frequently in restaurants in the neighborhood. This well-travelled section of town provided excellent cover for the handful of international scientists, engineers and technicians involved in the clandestine project.
The acquisition of the raw materials needed for Professor Modena's plan was quite easy as none of them were closely scrutinized. Thorium oxide was purchased through a fictitious front company from India and quantities of beryl mineral were shipped from Argentina enabling the chemists to produce beryllium oxide on site. Other common multi-purpose chemicals such as mineral acids, ion exchange resins, lead bricks and organic solvents were acquired mainly from China and from several companies in Europe.
In the deep basement the walls were lined with the lead bricks that served for radiation shielding. Four irradiation tunnels from the same materials led from the corners of the largest room in the basement to the center where a large stainless steel reactor vessel was placed.
As the stolen radioactive sources arrived at the laboratory site from all over Europe, they were moved to the basement and placed in the four lead covered tunnels. Measurements showed that only a very small amount of radiation reached the surface level. Due to the 27.5 days half-life of the protactinium-233 intermediate radio-nuclide the irradiated thorium oxide needed to be stored for three months before the uranium-233 could be efficiently extracted. For this purpose a storage space shielded with lead bricks was constructed in an adjoining room of the basement.
In the same room a chemical pilot plant was constructed to dissolve the "cooled" irradiated thorium oxide targets and to separate the uranium-233 produced through the sequence of nuclear reactions from the thorium and beryllium oxides. The thorium and beryllium were then recycled by precipitation as a mixed oxide and returned to the central reactor vessel for another irradiation cycle. The U-233 product was to be transferred to another section of the basement where it would be further purified by solvent extraction and ion-exchange.
Finally it was to be converted into a metallic form through a number of well-known chemical conversion steps. The uranium metal product was to be stored in a sealed vault, also coated with lead bricks, until processed into the shape and dimensions required for the core of the improvised nuclear device.
By the end of July all the parts were set in place. Stocks of thorium and beryllium oxides were admixed and ready for placement in the reactor. A sufficient number of gamma radiation sources had arrived and were placed in the lead tunnels. The staff had practiced using the separation and purification equipment with thorium and natural uranium that were only slightly radioactive and managed to produce high purity uranium metal. According to the calculations, overseen by Professor Modena, every week each batch would produce about 500 grams of U-233, so that the critical amount needed for a simple improvised nuclear device of 15 kg could be completed within about eight months of continuous operation of the facility.
After the production of the uranium metal it had to be cast and shaped to enable it to produce a fast chain reaction that would release enough energy to obliterate every living being and structure within a radius of a few hundred meters. It was assumed that this would take another couple of months to complete or somewhat less time if an experienced scientist would be put in charge of this stage. Professor Modena intended to ask Ollie to try and enlist a suitable candidate for this or at least obtain detailed blueprints of the device.
The irradiation of the first batch took a little longer than one week due some minor hitches, but then they had to wait for several weeks before uranium could be extracted from the irradiated thorium oxide. Extensive chemical and isotopic analyses showed that the U-233 produced did contain small amounts of the highly radioactive isotope of uranium-232 which made handling of the product more hazardous.
At the headquarters of the International Atomic Energy Agency, the IAEA, in the section responsible for tracking radiation sources, a flurry of activity started when an unexplained increase in the number of "orphan" sources was noted. Numerous reports of missing radiation sources were received from Sweden, Germany, France, Belgium, Italy and other European countries. These included gamma radiation sources of all kinds — Cobalt-60, Cesium-137, Iridium-192 and a few others. Strangely there was no change in the number of reports on missing sources for other types of radiation like beta or alpha sources. The Section Head, who was a political appointee from a South American country with financial ties to the president of that country, could not care less about this. However, Dr. Eugene Powers his permanent deputy, a professional health physicist from the United States, became deeply concerned about these missing sources. He contacted his Russian colleague who was also his opposite number in the Safeguards Section, Dr Vassilly Nomenkov, and proposed a private meeting over lunch.