A report released Wednesday by the Nuclear Threat Initiative (NTI) attempts to provide the first-ever public assessment of nuclear security in 176 countries.

The NTI Nuclear Materials Security Index, developed with the Economist Intelligence Unit, foremost provides a security ranking for the 32 countries possessing nuclear materials, with Australia scoring highest. Japan, still reeling from the disaster at its Fukushima Daiichi nuclear plant last March, ranked no. 23; the United States tied with Belgium at no. 13. North Korea, which today signaled willingness to suspend its uranium enrichment program in exchange for food aid, came in last.

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Countries were rated on a number of factors, including quantities of nuclear material and sites, on-site security measures, regulatory structures and political stability. The United States‘ standing, for example, was affected by its high volume of nuclear materials and sites.

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NTI Co-Chair and former U.S. Sen. Sam Nunn noted in the foreword to the report that the proliferation of nuclear materials, the expansion of technical knowledge on how to build a nuclear bomb, and terrorist intentions to acquire nuclear weapons threaten to become a “perfect storm” that could result in wide-scale disaster.

“We know that to get the materials needed to build a bomb, terrorists will not necessarily go where there is the most material; they will go where the material is most vulnerable,” Nunn writes. “That makes global nuclear security only as strong as the weakest link in the chain.”

The survey also ranked 144 countries that do not have significant nuclear materials, but could potentially be used as safe havens or transport routes. Of these, Finland ranked no. 1 and Somalia came in last, scoring poorly in areas such as political stability and pervasiveness of corruption.

NTI hopes its index will “stimulate discussion and define future commitments” at the 2012 Seoul Nuclear Security Summit in March, it said in a release.

You can see the full rankings, along with commentary and NTI’s recommendations, at the NTI Index site.