Graceful Submarine Exit Portrayed as Radiation Relief in Sardinia

Reasons for departure - select the best answer from #1, #2, or #3 (color and bold emphasis added):

(#1) The US administration announced last November that it was intending to leave the island but did not say when. It said that the "changing international security scenario" meant the Santo Stefano base was no longer strategically important to the United States. source

(#2) The move is part of a general reshuffling of U.S. military forces and resources throughout Europe designed to reflect post Cold War realities and to achieve greater operational mobility. source

(#3) The USS Oklahoma City collided with a commercial Norwegian vessel in the western Mediterranean in 2002, and the USS Hartford ran aground while on manoeuvres in La Maddalena harbour in 2003. The following year, a French research institute CRIIAD [sic]found exceedingly high levels of the radioactive element thorium, used as a nuclear power source, in seaweed samples. ...In 2005, the regional health department found higher than usual levels of cancer in the area. source

(#1) and (#2) are virtually identical, so let's consider the third possibility. The Italian government denied serious consequences from submarine accidents, but tests carried out on seaweed samples by French research institute Criirad [sic] in the immediate aftermath of the incident showed thorium levels 400 times higher than normal. source

---------------------------------DISCUSSION ----------------------------------

Is thorium even a nuclear power source for those U.S. Submarines? Thorium may be used in nuclear reactors instead of uranium as fuel. This produces less transuranic waste. source

[in thorium reactors] Each reactor needs its own facility (synchrotron) to generate the high energy proton beam, which is very costly. No synchrotron of sufficient power has ever been built. Recently, however, the Spallation Neutron Source with 1 GeV protons was completed for other experiments. source So, suppose such a reactor were deployed on some nuclear subs, in order to contaminate the seabed with it (radioactive thorium) the reactor compartment would have to be breached. No such event happened in either of the accidents and thoriated stuff just does not fall off submarines. Finally, there have not been many aircraft crashes into Maddelena Harbor.

Could another source of thorium explain abnormally high levels of thorium off La Maddelena Harbor? Thorium occurs naturally in the environment. Worker exposure comes primarily from mining, milling of uranium, phosphate fertilizer production, coal-fired utilities, welding with gas tungsten welding electrodes, and industrial boilers. Here are three more , common industrial uses of thorium:

+ Thorium has been used in heat-resistant ceramics.

+ As an alloying element in magnesium used in aircraft engines, Thorium imparts high strength and improved high temperature performance.

+ Thorium is used to coat tungsten wire used in electronic equipment, improving the electron emission of heated cathodes.

Except for related mining, milling and phosphate fertilizer production, most of the other activities are not unknown on submarine tenders, where environmental regulations are rigorously enforced.

What industries on Sardinia may be dumping thoriated wastes illegally? The US Navy's departure removes a convenient cover enjoyed by illegal dumpers or international mischief makers.

My guess is that the U.S. is either assisting Italy in identifying the true source of contamination, or has already shared that information. We may never hear about resulting arrests, because submarines are always silent and strange.