Yes, the material itself and the tritium triggers do require replacement - tritium more often than fissle material... But their are plenty of former Soviet scientists out there with the skillset to do so for the amount of money that the terrorists are willing to pay. Think about it... You go from being a fairly well fed skilled technician/laborer to an unemployed hungry person and someone says "We will pay you $25,000 American if you will do this for us no questions asked." Not only "not impossible", but instead, "very possible."
Raven6