IT IS often easy to ignore the news when something bad does not happen. The Post reported Sunday that hundreds of pounds of plutonium, enough for dozens of nuclear weapons, lay buried for years in Kazakhstan at the Semipalatinsk test site after the collapse of the Soviet Union and the end of the Cold War. After prodding by scientists, the United States, Russia and Kazakhstan entombed the plutonium in concrete so it could not be seized by scavengers, terrorists or states with malevolent intent. Good work — and the end of the story, right?

Not quite. Should the world face another moment in which a nuclear weapons state is caught in upheaval, the Semipalatinsk operation offers valuable lessons for the future. Perhaps the most striking is the need to overcome mistrust and secrecy so the abandoned plutonium can be found. The Post article and a longer report by the Belfer Center at Harvard make clear that a major hurdle was pinpointing the material near Degelen Mountain. Russia, successor to the Soviet Union’s nuclear arsenal, knew the whereabouts, but it was reluctant to reveal them. The coordinates emerged slowly, over more than a decade, largely because scientists and experts collaborated to ease suspicions. They acted without cumbersome negotiations and treaties. The $150 million price tag, paid by the United States, seems to have been a good investment, considering the danger that the plutonium might otherwise have been carted away by terrorists or states seeking to build a bomb.

Nuclear security dangers are still out there. President Obama’s call in 2009 to “secure all vulnerable nuclear material around the world in four years” galvanized prime ministers and presidents, and actionfollowed. Many of the most egregious security gaps evident after the Cold War — sites with gaping holes in fences, no detectors to set off alarms and so on — have been closed. But there are facilities where security measures are still insufficient to protect against threats by terrorists and criminals. Russia, with the world’s largest stocks of nuclear materials, has made great strides, but these materials remain scattered across an archipelago of bunkers and buildings. Pakistan, which has ramped up the pace of its nuclear bomb-building in recent years, is a continuing worry as a possible target of terrorist attack.

There are also many research reactors around the world with enough highly enriched uranium to fabricate at least one bomb with only minimal security in place. An attack in South Africa in November 2007 still haunts those who worry about theft and terrorism. Two armed teams spent 45 minutes inside the guarded perimeter of the Pelindaba facility, which houses hundreds of pounds of weapons-grade material, without encountering the site security force. They didn’t seize any material but escaped and were never caught.

Nuclear security should always be a story of bad things that do not happen. That requires hard work and vigilance to make sure nuclear material that could be used for a bomb is never stolen.

Read more about this issue:

The Post’s View: Start talks with Iran

The Post’s View: Without U.S. aid, will Russia keep scrapping its nuclear arsenal?

Henry Kissinger: Nuclear weapons reductions must be a part of strategic analysis

Jim Hoagland: Obama’s misplaced push for abolishing nuclear weapons

Charles Krauthammer: Nuclear posturing, Obama-style