As Obama Prepares to Push Nuclear Test Ban, Technological Basis Still Debated

(Jul. 15) -A 1971 French nuclear test nuclear at Mururoa Atoll, French Polynesia. Experts continue to differ over the effectiveness of systems that would be critical to detecting nuclear test blasts and assessing nuclear-weapon reliability if the Comprehensive Test Ban Treaty enters into force (Getty Images).
(Jul. 15) -A 1971 French nuclear test nuclear at Mururoa Atoll, French Polynesia. Experts continue to differ over the effectiveness of systems that would be critical to detecting nuclear test blasts and assessing nuclear-weapon reliability if the Comprehensive Test Ban Treaty enters into force (Getty Images).

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WASHINGTON -- It has been 12 years since the U.S. Senate last considered the Comprehensive Test Ban Treaty, which supporters say has been enough time for technology to catch up with the concerns that previously derailed the pact (see GSN, May 11).

Those developments, they hope, will give the treaty a fighting chance when it goes back to Capitol Hill.

Since the early days of his term, President Obama has made it clear he intends to submit the accord for approval by the Senate as part of his administration's broader nonproliferation campaign. Top officials have discussed the general outlines of a strategy for securing ratification, but it remains to be seen when it will be put into play.

Treaty proponents argue that the United States should now feel assured it can keep its nuclear arsenal in working order without actually setting off weapons, and can be confident that no other nation could carry out a secret test blast.

They say the time is right for lawmakers here to ratify the treaty, furthering its chances to become a global regime and taking another step to stem the spread of nuclear weapons.

"It is really very difficult to develop a functional nuclear weapon without the nuclear tests. And for those countries that already have nuclear weapons it puts a cap on new and advanced nuclear weapons," said Annika Thunborg, spokeswoman for the Preparatory Commission for the Comprehensive Test Ban Treaty Organization.

"The ultimate question is ... what world do countries want to live in? And this is of course a question that many American presidents have asked," she told Global Security Newswire.

Critics have a different take, saying developments since 1999 have only made more obvious the dangers of accepting a binding prohibition on nuclear blast trials.

Computer modeling cannot effectively replace actual testing in terms of ensuring the upkeep of today's stockpile, nor for preparing new nuclear weapons that might one day be necessary to safeguard the United States from future threats, skeptics assert.

They question whether other governments would fall in line behind Washington in approving the agreement, and argue that some nations could still pull off atomic explosions without the outside world knowing.

"Entry into force would buy nothing," said Kathleen Bailey, former U.S. deputy assistant secretary of State. "States could still cheat without detection, and probably would."

A History of Testing

The United States set off the atomic arms race with the development and use of nuclear weapons during World War II. Over 51 years, there would be more than 2,000 underground, underwater and above-ground nuclear test detonations by the five recognized nuclear powers: China, France, Russia, the United Kingdom and the United States.

The technical purpose was to ensure the efficacy of nuclear weapons and to determine how they worked against buildings and living beings. Politically, they were forceful demonstrations of certain nations' military capabilities.

The impact of these events was not limited to assisting the proliferation of nuclear weapons, though the total environmental and human cost might never be known.

More than 500 atmospheric tests conducted by the nuclear powers from 1945 to 1980 spread radiation across the globe, according to one assessment. A 2003 study by the Centers for Disease Control and Prevention and the National Cancer Institute estimated that roughly 11,000 deaths might have been caused by radiation from the blasts, primarily through thyroid cancer linked to exposure to iodine 131. Other projections have been more dire.

"There have been lots of very depressing studies about the impact around Semipalatinsk," the Soviet nuclear testing site in what is now Kazakhstan, "but I wouldn't want my worst enemy to have to view some of that stuff," according to arms control specialist Jeffrey Lewis.

Pressure to curb nuclear testing began in the early years of the atomic era, according to a CTBTO history. There was some success through agreements such as the 1963 Limited Test Ban Treaty that prohibited atmospheric, underwater and space-based testing, but for decades no full-scope prohibition.

Two years of talks in Geneva, Switzerland, ended in 1996 with formalization of the Comprehensive Test Ban Treaty, which today has 182 signatory states. Each member has agreed not to conduct any nuclear trial blast no matter how small the yield, Thunborg said. That assertion, like many involving the accord, is questioned in some quarters.

The Preparatory Commission was stood up to lay the groundwork for an actual CTBT verification organization, once the agreement enters into force.

That, though, has proved sticky. The pact must be ratified by the "Annex 2" states -- 44 nations that were involved in negotiations while in possession of nuclear research or power reactors. There are still nine holdouts among that group: China, Egypt, India, Indonesia, Iran, Israel, North Korea, Pakistan and the United States.

Washington has observed a voluntary moratorium on nuclear testing since 1992. The Clinton administration submitted the treaty for Senate advice and consent, only to see it rejected in a 51-48 vote in October 1999. The tally was less close than it might seem, as two-thirds backing would be required for ratification.

Lawmakers and former top officials at the time raised a number of objections to the agreement, such as its potentially detrimental effect on the U.S. nuclear deterrent.

The U.S. Stockpile Stewardship Program had been initiated only five years earlier. The effort was intended to ensure the U.S. arsenal remained safe, secure and reliable without nuclear tests, but its capability to do that at the time remained in question, the Congressional Research Service said in a 2008 report.

"If we need nuclear weapons, we have to know they work. That is the essence of their deterrence," former Reagan administration Defense Secretary Caspar Weinberger asserted during the first debate. "The only assurance you have that they work is to test them."

Another major concern was whether the detection regime was up to the task of catching cheaters. While the five nuclear powers had by that time on their own stopped detonating nuclear devices, rivals India and Pakistan just one year earlier had conducted a series of underground test blasts.

The debate goes on regarding whether those concerns have been fully addressed in the years since the 1999 debate.

Catching Nuclear Cheaters

Twelve years ago, no detection stations or laboratories had been certified for inclusion in the planned web of technology for identifying nuclear detonations, according to Lassina Zerbo, director of the CTBTO International Data Center.

The treaty's International Monitoring System ultimately will feature 16 laboratories and 321 stations to detect seismic rumbles, radiation releases or other signs of nuclear explosions that might occur underwater, in the atmosphere or below the earth's surface.

"Ten years ago ... we had no certified facilities, today we have 265 certified facilities," Zerbo, whose operation analyzes and transmits information from the detection facilities, told GSN during a March interview at the organization's headquarters in Vienna, Austria.

The Preparatory Commission cites detection of North Korea's 2006 and 2009 underground nuclear blasts as evidence of its capabilities.

Even with less than two-thirds of the detection system installed five years ago, more than 20 facilities identified the seismic impact of the North's first test. Data and a preliminary analysis pointed to an underground nuclear detonation; information including the magnitude, depth and time of the event was issued to CTBT member states within hours, and a full report confirmed the assessment two days after the incident.

A radionuclide station in Canada reported elevated levels of xenon gas that the organization was able to track back to North Korea, further cementing the conclusion that the Stalinist state had, as promised, detonated a nuclear device.

The organization's detection infrastructure was nearly 80 percent ready when the North conducted its second nuclear blast in 2009. Even as television news reports noted an earthquake in the region, the CTBT office in Vienna had again gathered detailed information suggesting that the event appeared instead to be an explosion.

Treaty states within 48 hours received tangible, detailed evidence indicating the North had set off another nuclear device, according to CTBT officials.

Critics have noted that the detection complex in 2009 did not pick up any noble gases that would be expected to be emitted by a nuclear explosion.

"It is the quality, not the quantity, of measurements or devices that could theoretically detect a nuclear explosion that really matters," Senator Jon Kyl (R-Ariz.), a longtime opponent of the CTBT regime, said in March during the Carnegie International Nuclear Policy Conference. "I would note that even if you add the sophisticated United States capabilities beyond the international capabilities, we were not even able to verify the test that was announced in advance by the North Koreans in 2009."

Zerbo said there are "different schools of thought" on why that occurred, but declined to elaborate.

"No one picked up on the noble gas ... not the United States, not Russia, not China, not South Korea, not Japan," he said.

Nonetheless, it is "unlikely for several reasons" that any nation could get away with a nuclear test unnoticed, Zerbo asserted. The organization's seismic monitoring system has been found able to detect blasts with yields much lower than 1 kiloton, Thunborg said.

The 2006 North Korean blast has been assessed at about a half-kiloton. By comparison, the U.S. Trinity nuclear test in 1945 had a 19-kiloton yield.

Skeptics remain unconvinced that the door has closed on the possibility of secret, undetected nuclear explosions.

There are a number of options for nations to get away with nuclear testing, such as conducting a "decoupled" blast within a specialized container or underground space, the National Institute for Public Policy said in an analysis issued this year."This can reduce the seismic signal below the threshold of detectability."

Nuclear blasts of a kiloton or higher could be masked against detection while still offering value in creation of new weapons and in maintaining existing systems, the report asserts.

"Most experts with relevant technical expertise agree that the [CTBT International Monitoring System], even supplemented with national technical means, cannot detect decoupled nuclear explosions of one to two kilotons, and perhaps of several kilotons," Bailey, who co-authored the NIPP report, stated by e-mail.

Treaty evaders could pull off a series of successive activities that might allow them to quietly build up reserves of information and know-how, according to some observers. They could glean information on nuclear physics and testing, among other related matters, through detonations of minimal yield.

Undersecretary of State for Arms Control and International Security Ellen Tauscher played down that threat in May.

"Could we imagine a far-fetched scenario where a country might conduct a test so low that it would not be detected? Perhaps. But could a country be certain that it would not be caught? That is unclear," she said during the Arms Control Association's annual meeting in Washington. "Would a country be willing to risk being caught cheating? Doubtful, because there would be a significant cost to pay for those countries that test."

Tauscher did not elaborate on the costs.

Analysts emphasize the value added by national capabilities to the treaty organization's complex of detection equipment. The pact authorizes states to use their own means for determining whether a nuclear test explosion has occurred, including satellites, intelligence and any of the 16,000 seismic stations installed across the globe, said Jenifer Mackby, a former CTBTO official who is now an adjunct fellow at the Center for Strategic and International Studies in Washington.

The International Monitoring System provides data that no country could access on its own, Mackby said. Alongside that infrastructure "you have enhanced national capabilities. Almost all countries in the world have seismic stations," she told GSN. "So I think that's a large development as well. ... You have more capability in some respects than any country could gather on its own."

Mackby also noted that bringing the treaty into force would allow treaty states to request that the CTBTO Executive Council authorize short-notice, on-site inspections of states suspected of conducting a nuclear test. She acknowledged others' doubts on whether an executive body of member nations with varying allegiances would sign off on such a visit. However, Mackby said representation by the five nuclear powers makes it "quite feasible" that the council could gather the votes in support of an inspection.

"If countries send qualified experts to the council, most of the members will vote on the technical and credible merits of the case rather than making it strictly a political exercise," Mackby stated.

The converse fear is that the treaty's contribution to nuclear nonproliferation could be undermined if a nation simply forgoes testing in developing a weapon, possibly by using an existing design acquired from another country.

"Today, I’m not so sure that you need” a test detonation to verify a nuclear weapon works as planned, former International Atomic Energy Agency chief inspector Olli Heinonen said during a panel discussion this week in Washington. “I don’t think there’s an easy answer, but I would not start to wait for a nuclear test" (see GSN, July 14).

Stockpile Stewardship

Speaking on May 10, Tauscher highlighted U.S. capabilities both to support the international regime against nuclear testing and to keep its own nuclear weapons in working order.

Directors of the nation's national laboratories say the Stockpile Stewardship Program, carried out by the Energy Department's semiautonomous National Nuclear Security Administration, "has provided a deeper understanding of our arsenal than they ever had when testing was commonplace," she said.

The effort involves a number of activities carried out at the nuclear laboratories and associated facilities, including surveillance of weapons parts as they age and production of replacement components. The United States through last fall had also conducted 24 "subcritical" tests to study the behavior of plutonium under explosive conditions without actually setting off a nuclear detonation.

Stockpile Stewardship, which in recent budgets has received more than $6 billion in annual funding, has formed the basis for yearly findings that the arsenal is both safe and reliable, the 2008 CRS report states.

A key 2002 study from the National Academy of Sciences also determined that with sufficient resources and focus, the nation could carry out the technical operations to ensure the viability of the stockpile under the CTBT regime.

The ability of supercomputers to model the behavior of a nuclear-weapon detonation is paramount to this program, and was central to the treaty's defeat in 1999, according to Lewis.

"Computing power was a crucial benchmark that was established in the 1990s and concerns about computer power were front and center in the objections of many senators, most of [whom] did not object to the treaty directly but only to what they claimed was an early consideration of it," the expert, who heads the East Asia Nonproliferation Program at the James Martin Center for Nonproliferation Studies, told GSN.

During the 1999 debate, heads of some of the nation's nuclear-weapon laboratories said it would be years -- possibly up to a decade -- before supercomputers would have the capacity to perform their stockpile mission.

Bruce Goodwin, a veteran nuclear-weapon scientist with the Los Alamos and Lawrence Livermore national laboratories, at the time said he could imagine by 2004 to 2005 a computer with 100 teraflops of computing power -- meaning it could conduct 100 trillion floating-point operations per second.

In 2008, the Energy Department said its new "Roadrunner" computer could conduct more than one thousand trillion calculations per second. An even more powerful computer was set to be assembled at the Lawrence Livermore National Laboratory this year.

The massive leaps in supercomputing power should resolve questions about nuclear blast modeling, surmounting another obstacle to U.S. approval of the treaty, Lewis said.

Questions persist on whether life-extension activities including replacement of parts would over time change warheads to the degree that testing would be necessary to ensure they still function as expected. Updating today's weapons "beyond the design envelope validated by nuclear testing ... could result in defects in life-extended warheads that could cause them to fail," the Congressional Research Service said in its 2008 assessment.

The JASONs, a group of high-level scientific advisers to the government, said in 2009 that there is "no evidence that accumulation of changes incurred from aging and [life-extension programs] have increased risk to certification of today's deployed nuclear warheads."

Speaking at the Carnegie conference, Kyl said that Stockpile Stewardship has offered "both good news and bad news" about the state of the U.S. nuclear arsenal. He expressed doubt that stockpile upkeep and life-extension efforts could ultimately keep the weapons working, and said the time is not yet right to forever swear off nuclear testing.

The lawmaker's office did not respond to requests for further comment about the stockpile issues cited in his speech.

There is also the question of whether today's arsenal will hold up for the challenges posed by future threats, particularly if the personnel and facilities central to sustaining the complex are allowed to stagnate, critics say.

New weapons might be required to counter new dangers, and testing might be necessary for the design and manufacturing of new deterrence systems, according to the NIPP report.

The United States could determine it requires a nuclear warhead capable of eliminating hardened, underground facilities that pose a threat to national security, only to be prohibited by the test ban treaty, said Baker Spring, a research fellow on national security policy at the conservative Heritage Foundation.

The Bush administration pursued research on a nuclear "bunker buster," but ultimately dropped the effort in the face of congressional opposition (see GSN, Oct. 26, 2005).

"A strict adherence to the CTBT as drafted would prevent the creation of new nuclear weapons to meet new nuclear missions. To me that's the fundamental flaw with the treaty," Spring said.

All of these issues -- and more -- could be raised when the treaty goes back to the Senate. How much sway the technological developments of the last decade will have in determining the accord's chances for approval will be determined only then.

"Everything in D.C. these days is extremely polarized," Mackby said. "No matter what the virtues are, in the end this treaty and many other things are likely to be based on political decisions, more than technical."

On Monday, Global Security Newswire will look at the Comprehensive Test Ban Treaty's ratification prospects in the U.S. Senate, and how the outcome might affect the calculus of other nations needed to bring it into force.

July 20, 2011
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First in two-article series