Stanford nuclear experts said they were skeptical of North Korea’s claim that it had detonated a hydrogen bomb this week.

However, they said the test was an important step forward for North Korea’s nuclear program and would have a destabilizing effect on the entire region.

“I don’t believe it was a real hydrogen bomb, but my greatest concern is not so much whether or not they actually tested a hydrogen bomb, but rather that they tested at all,” said Siegfried Hecker, former director of Los Alamos National Laboratory and senior fellow at Stanford’s Center for International Security and Cooperation.

North Korean dictator Kim Jong-un has “a track record of exaggerated statements, hyperbole and outright lies,” according to Scott Sagan, Caroline S.G. Munro professor of Political Science.

“The propaganda machine in North Korea has made all sorts of claims about Kim Jong-un’s personal prowess and his history, and it is totally unsurprising that he might make exaggerated claims about North Korea’s military prowess,” Sagan said.

Former U.S. Secretary of Defense William J. Perry said he also doubted that North Korea had detonated a two-stage hydrogen bomb.

“Whether it’s a hydrogen bomb or not, it’s very dangerous, destabilizing development,” said Perry.

“It’s obvious they’re working to increase the capability and size of their nuclear arsenal and that represents a huge danger to the region and creates major instability and major concerns on the part of South Korea and Japan.”

Many North Korea watchers had been anticipating another nuclear test.

“We’ve thought that the North Koreans could test at any time – that the tunnels were ready, that they could do this at any time – so it would be a political decision, not a technical decision,” said Thomas Fingar, senior fellow at the Freeman Spogli Institute for International Studies.

Hecker said North Korea’s latest nuclear test would move the country closer to being able to miniaturize a nuclear warhead and mount it on a missile, extending the reach of their nuclear weapons.

“They will have achieved greater sophistication in their bomb design – that is the most worrisome aspect,” Hecker said.

“At this point, what makes their nuclear arsenal more dangerous is not so much explosive power of the bomb, but its size, weight and the ability to deliver it with missiles.”

On the diplomatic agenda, the U.S. and its allies will likely push for stronger sanctions in the wake of the tests, according to Kathleen Stephens, a former U.S. Ambassador to the Republic of Korea and William J. Perry fellow at Walter H. Shorenstein Asia-Pacific Research Center (APARC).

“In the UN the U.S., Japan and South Korea will likely look for another, and stronger, UN Security Council resolution, presumably with some efforts to attach to it some teeth and strengthen sanctions,” Stephens said.

The U.S. Congress is currently considering financial sanctions that would cut of all access to U.S. banks for any banks dealing with the North Koreans.

But financial sanctions would likely be less effective in dealing with North Korea than they had been with Iran, according to Fingar.

“It’s like hitting a masochist,” said Fingar.

“North Korea is relatively insulated from the external economy, where Iran wasn’t. Iran had a middle class, you could make sanctions hurt, they could have a real effect. You could make it hard for the North Koreans to buy luxury goods, but at the end of the day, is that going to bring down the regime?”

Financial sanctions against North Korea could have the unintended consequence of also hurting China, said David Straub, associate director of the Korea program at APARC.

“This could be problematic for China because many of the transactions that North Korea conducts would be going thorough Chinese banks, and the Chinese, understandably might not be happy about the US financial sanctions on them, in effect,” Straub said.

Perry recommended that the U.S. reinvigorate diplomatic talks with North Korea in collaboration with China, South Korea, Japan and Russia.

“I would not give up on negotiations with North Korea yet,” Perry said.

“What could have been done many years ago was following through on negotiations with North Korea at the turn of the Century, which were proceeding robustly in the last years of Clinton’s second term, but were abandoned by the Bush Administration...That was a geo-strategic error.”

But Hecker said those negotiations would be harder now.

“I have previously argued that we should focus on three “No’s” for three “Yes’s” – that is no more bombs, no better bombs (meaning no testing) and no export – in return for addressing the North’s security concerns, its energy shortage and its economic woes,” said Hecker.

“This could have worked when I first proposed it 2008 after one of my seven visits to North Korea. It will be more difficult now."

The Department of Energy's long-term plan for dealing with material contaminated with plutonium and heavier elements from the U.S. weapons program is to bury it underground at the Waste Isolation Pilot Plant in southeastern New Mexico.

The Energy Department's plan aims to safeguard nuclear material for the next 10,000 years. But three Stanford nuclear scientists point out in a new commentary article in the journal Nature that the Waste Isolation Pilot Plant (WIPP) was not designed to hold as much plutonium as is now being considered for disposal there. And, in fact, the site has seen two accidents in recent years.

"These accidents during the first 15 years of operation really illustrate the challenge of predicting the behavior of the repository over 10,000 years," said Rod Ewing, the Frank Stanton Professor in Nuclear Security at Stanford and a senior fellow at the Center for International Security and Cooperation.

What's more, there's more plutonium proposed for disposal at WIPP in the future, a result of treaties with the former Soviet Union and now Russia to decrease the number of nuclear weapons by dismantling them.

A recent assessment of what to do with the plutonium from dismantled weapons has proposed that the material be diluted and disposed of at WIPP. But this analysis does not include a revision of the safety analysis for the site, wrote Ewing and his two Stanford co-authors in the Department of Geological Sciences, postdoctoral scholar Cameron Tracy and graduate student Megan Dustin.

They call on the U.S. Department of Energy, which operates WIPP, to take another look at the safety assessment of the site. Particular emphasis should be on the estimates of drilling activity in the oil-rich Permian Basin, where WIPP is located, and on the effects of such a huge increase in the plutonium inventory for the pilot plant.

"The current regulatory period of 10,000 years is short relative to the 24,100-year half-life of plutonium-239, let alone that of its decay product, uranium-235, which has a half-life of 700 million years," the researchers wrote.

"We cannot be certain that future inhabitants of the area will even know WIPP is there," they added. As a result, it is important to understand the impact of future drilling in the area.

The waste is stored 2,150 feet below the surface in hundreds of thousands of plastic-lined steel drums in rooms carved out of a 250-million-year-old salt bed. The repository is at about half of its planned capacity and slated to be sealed in 2033.

The researchers question some of the assumptions used in the safety studies. For example, to determine the odds of oil drilling in the future, the study uses a 100-year historical average drill rate, even though drilling has intensified in recent decades, throwing this assumption into question.

The Stanford experts also suggest more attention to how the buried materials may interact with each other, particularly with salty brine, over centuries. A single storage drum may contain a variety of materials, such as lab coats, gloves and laboratory instruments; thus, the chemistry is complex.

Ewing said that the complacency that led to the accidents at WIPP can also occur in the safety analysis. Therefore, he advises, it is important to carefully review the safety analysis as new strategies for more plutonium disposal are considered.