Looking for nukes

How hard could it be to find hundreds of tons of radioactive nuclear material? We've certainly got plenty of motivation to keep tabs on this stuff. There's the threat of terrorist groups like Al Qaeda, the standoff between Pakistan's and India's arsenals and North Korea's Kim Jong II. Iran, the next big nuclear challenge, already has missiles that can strike Israel and a thriving civilian nuclear-power program. It claims to have no ambition for nuclear weapons, but verifying this is critical. We must know how much to press for a diplomatic solution or how seriously to consider a military strike. Nuclear intelligence, however, is problematic. Despite all the high-tech gear that intelligence agencies have developed, facts on the ground are so thin that the whole question of what countries like Iran are doing with nuclear weapons is vulnerable to manipulation by policymakers. Who can forget how Condoleezza Rice, as head of the National Security Council in September 2002, declared that the United States could not let the 'smoking gun' of Iraq's nuclear program become a mushroom cloud? Too often intelligence about clandestine nuclear programs is spotty and can easily be misread. Many people might think that technology allows spies to easily snoop on weapons plants, but that is not true. Satellite images can flag buildings suspected of being part of a nuclear-weapons program, but they cannot reveal what goes on inside. It's easy to hide a gas-centrifuge plant, which is needed to take ordinary uranium and turn it into highly enriched uranium for weapons. Spy-satellite photos of new construction at pre-1991 Iraqi nuclear-weapons sites helped convince the CIA that Iraq was building a uranium-enrichment plant. It turned out to be a repair shop for military radar, The chief evidence U.S. intelligence agents mustered on Iraq was a shipment of thousands of aluminum tubes thought to be key components of a gas centrifuge. Intercepted nuclear hardware and communications are powerful intelligence tools, but they're often ambiguous. In the case of Iraq, the aluminum tubes were probably intended for artillery rockets. Another tactic 'placing 'bugs' inside such dual-use equipment and arranging to have it traded on the black market uncovered secret installations in Libya. But it failed in Syria; the dual-use items could not be linked to nuclear weapons