Recently in Nuclear weapons Category

The Department of Energy's National Nuclear Security Administration awarded a five-year, $25 million grant to a consortium of academic organizations headed by the University of California, Berkeley (UCB) that will train graduate and undergraduate students to work in the fields of nuclear security and nonproliferation. The National Science and Security Consortium will also involve Michigan State University, UC Davis, UC Irvine, the University of Nevada, Las Vegas, and Washington University in St. Louis.

The students will participate in the nuclear security R&D projects at the NNSA-owned weapons laboratories, Los Alamos, Lawrence Livermore and Sandia national laboratories. Anne Harrington, NNSA deputy administrator for defense nonproliferation, said the UCB collaboration topped a number of bids submitted by other university teams in response to NNSA's request for proposals. The consortium will train students in nuclear physics, nuclear and radiation chemistry, nuclear engineering, nuclear instrumentation and public policy.

Although NNSA annually funds about $15 million worth of research at US universities, those interactions involve directed R&D projects, with the academic partner performing research for one of the three NNSA weapons laboratories. The new collaboration will be "exploratory and we hope, very innovative," she said. "If we don't keep the vital pipeline of talent coming into our laboratories, and more importantly, if we don't excite a new generation about the importance of working on nuclear security and nonproliferation issues, it doesn't matter how beautiful our facilities are; we will not be able to do the work that must be done."

Referring to the collaboration, Per Peterson, chair of UCB's nuclear engineering department, said that "coordinating efforts at the partnering universities and creating linkages with national laboratories will give students the opportunity to gain a much broader interdisciplinary perspective on why their research matters and what it's going to be able to do." Interest in that field has "grown enormously over the past several years," he said, and his students tell him they think they have an opportunity to change the world's future. The consortium goes well beyond typical small grants to principal investigators, which provide a "stovepiped environment."

Through the consortium, participating faculty from engineering, chemistry, physics and public policy departments plan to collaborate in a fashion that mirrors the interdisciplinary model found at national laboratories. If a public policy-related question were to come up, a teleconference could be arranged with officials at NNSA, the Department of State, or other relevant agencies.

Nuclear resonance fluorescence

One topic of investigation for the consortium is nuclear resonance fluorescence for the detection of nuclear materials. The technology, in which gamma-ray photons with the appropriate energy can generate fission in uranium, could provide a new method for detecting nuclear materials in locations that are very difficult to monitor by other means and would also be capable of identifying the specific isotope that is present. "A whole host of applications" could further ensue from developing NRF, Peterson said, such as in verifying arms control agreements, where inspectors have to ascertain the presence of a warhead without disclosing classified design information.

Another topic the consortium could explore is the growing risk that uranium ore concentrates are diverted to terrorists or rogue nations, Harrington noted. The risk is heightened by the fact that many uranium mines are in developing countries having high levels of corruption. "That gives us a natural opportunity to engage a broad set of countries in very low-level, fundamental nuclear forensics materials analysis and characterization using uranium as the base, but in a form that is completely non-sensitive," she said. "So we can explore things like geological watermarking. We can explore different ways of developing and controlling databases on things like uranium ore concentrates." Scientific advances from that work might be transferred into the highly sensitive field of post-detonation nuclear forensics, she added.

Over the program's five years, a total of 230 students are expected to be trained by the program over the five years, Harrington said. Six graduate students are to be enrolled at UCB initially, with that number doubling in later years, Peterson said.

David Kramer

Ensuring that Russia complies with the New START nuclear arms reduction treaty will require more sophisticated and exacting technologies than the counting procedure that was used in the predecessor agreement, according to a senior Department of Energy official.

US arms inspectors who examine Russia's strategic missiles will now employ neutron detectors when they tally warheads, said Anne Harrington, deputy administrator for defense nuclear nonproliferation at the department's National Nuclear Security Administration (NNSA).

Under the previous arms pact, the 2002 Treaty of Moscow, verification consisted of counting the number of so-called shrouded bumps—that is, the warhead-laden reentry vehicles on the tips of strategic missiles. New START stipulates that those bumps will be considered to be warheads unless they can be positively shown to be non-nuclear in nature, Harrington said in a briefing to the President's Council of Advisors on Science and Technology on 8 March.

The neutron detectors currently carried by US inspection teams consist of a tube filled with helium-3 (the detection medium), which is surrounded by polyethylene and encased in cadmium. The cadmium serves to capture any thermal neutrons, which do not necessarily connote a warhead. The polyethylene serves to slow the telltale fast neutrons, which are emitted by plutonium in warheads, and enables those neutrons to be efficiently counted in the tube. Under New START, a neutron count just slightly above background will be considered as showing that a nuclear warhead is present.

Surging demand for ³He used in radiation detection at US ports of entry and a plunge in its production—most ³He comes from the decay of tritium in dismantled warheads—have created a shortage of the isotope. To replace ³He-based neutron detectors, Harrington said that the NNSA has been developing new technologies, some of which are nearing commercialization.

Verifying future treaty stipulations

Further advances in hardware and software will be needed to verify provisions agreed to in future arms reductions accords, she said. One challenge will be developing a system that can be used "in situ, with minimal operational impact" to count stored warheads or their nuclear components, neither of which is covered under the new START.

One technology under development would use a technique developed for high-energy astronomy. Like hard x rays and gamma rays, neutrons emitted by stored weapons cannot easily be focused. In principle, you can form an image by using a pinhole camera, but that approach discards most of the neutrons. A more efficient approach is to send the neutrons through an irregular grid of neutron-blocking areas and open areas, a so-called coded aperture.

"This approach," said Harrington, "allows approximately one-half of the neutrons to be counted and is so much more sensitive than a pinhole, where most of the signal is lost. The neutrons that reach the plane where the film would be in a pinhole camera can then be used to construct an image using a simple computer program."

The technique takes advantage of the ability of neutrons to pass through multiple meters of a variety of intervening materials. In addition, the data reveal little or nothing about the warhead design, allowing those details to be kept secret from the other party. An image of a warhead would consist of bright spots against a dark background.

New START, which took effect in February, requires the US and Russia to reduce their nuclear stockpiles to 1550 deployed strategic nuclear warheads each by no later than 2019. That compares with the 1700 to 2200 warheads that were permitted under the Treat of Moscow, which expired in 2009.

As the numbers of weapons continue to decline, the need for high confidence in the numbers that remain will grow. More intrusive verification measurements and procedures will therefore be needed, Harrington said. In such an environment, the need to keep warhead design information secret can be addressed by putting information barriers in place. Computers can take automated measurements and, using algorithms, verify the data against declarations. The sensitive data measured will not be stored. Instead, an indicator will provide a pass–fail reading. The computer and software can be jointly designed by experts from both parties to a treaty, she added.

The NNSA is also working on techniques to monitor and verify the dismantlement of weapons and the storage and disposal of their fissile materials. There are ways to prove to the other side that a weapon has been taken apart without having to show the parts, she said. For example, a weapon being dismantled might be placed in a container and checked with radiation monitors at multiple points during the process. The monitors would determine the presence of fissile materials consistent with expectations at that point in the disassembly, ensuring that the materials have not been diverted.

Also in development by NNSA is an ultra-fast detection and timing method for measuring the correlated gamma and neutron signals of individual fissile materials, a technology that will provide highly accurate measurements of nuclear materials throughout the dismantlement process.

Harrington said it is inevitable that other nations will join future arms control treaties. Their stockpiles, which are still dwarfed by the US and Russian arsenals, will become relatively larger as those of the two nuclear giants continue their steep declines. She urged other nuclear weapons states to join now in the cooperative development effort for new verification technologies, well before they begin making reductions to their own stockpiles, so that they can feel comfortable with them.

Harrington told the members of President's Council of Advisors on Science and Technology about a warhead dismantlement verification exercise that took place last year, in which Norway played the role of the nuclear weapons state and the UK was the inspecting country. Though longtime allies, the two sides had great difficulty until they agreed to jointly develop the technology they would use in the exercise. "Once they got past that barrier, the rest of the exercise went fine," she said, an indication that "engaging in joint technology can overcome political obstacles to making an exercise successful."

David Kramer

A bill to create a domestic supply base for molybdenum-99, a short-lived radioactive isotope widely used for medical imaging, was reintroduced in the Senate in late January. Virtually identical to a measure that passed the House by a 400–17 vote last year, the bill (S-99) would codify and authorize funds for an interagency effort already under way to help establish a US supply of ⁹⁹Mo that would be produced without the use of highly enriched uranium (HEU).

The introduction of S-99 restarts a legislative push that stalled last year due to opposition from a single lawmaker, Senator Christopher Bond (R-MO). Bond, who retired in December, used a Senate procedure known as a hold to prevent the measure from coming to a vote. The measure aims to establish a reliable source of ⁹⁹Mo in the US and to prevent a recurrence of a shortage like the one that occurred last year, when two of the five research reactors that account for nearly all the world's supply of the radioisotope were shut down for the better part of 2010.

The US, which consumes about half the world's ⁹⁹Mo output, imports material from a Canadian company and from two European suppliers. A fourth producer, located in South Africa, serves mostly customers located outside North America. Because of its 66-hour half-life, ⁹⁹Mo can't be stockpiled. It is the parent of the even shorter-lived technetium-99m, which is used as a tracer in about 18 million US medical diagnostic procedures each year.

At a 1 February hearing before the Senate Committee on Energy and Natural Resources—Parrish Staples, director of the office of European and African threat reduction, at the Department of Energy's National Nuclear Security Administration—welcomed the bill's provisions to phase out use of HEU in ⁹⁹Mo production. The American Medical Isotopes Production Act would prohibit US exports of HEU in seven years, a deadline that could be extended by as much as six years if the administration determines that there is insufficient ⁹⁹Mo produced without HEU.

To reduce the threat the material poses to nuclear proliferation, the Obama administration is pressuring other nations to end all civilian uses of HEU, including for medical isotopes. The US, however, continues to export HEU to Canada for ⁹⁹Mo production there. Since 2005, the Nuclear Regulatory Commission has licensed seven shipments of HEU to Canada and Belgium for use in medical isotope production, according to Margaret Doane, director of NRC's international programs. Two more license applications, from Canada and France, are pending before the commission.

NNSA is offering financial and technical assistance for ⁹⁹Mo producers to convert their HEU-based production processes to low-enriched uranium. Last year, with NNSA's help, the South African Nuclear Energy Corp (Necsa) became the first of the major producers to ship a commercial quantity of the isotope that was made without HEU.

The Senate bill would authorize $143 million over three years for the development of HEU-free domestic production sources. NNSA has cooperative agreements in place with four US industry teams, each of which is developing a different novel approach to manufacturing ⁹⁹Mo. The cost-shared grants allow for up to $25 million in federal funds for each of the teams: GE Hitachi Nuclear Energy, Babcock & Wilcox, NorthStar Nuclear Medicine and Morgridge Institute for Research.

Three of the processes would not require uranium of any type. But Staples warned that long-term subsidies provided to the current HEU-based ⁹⁹Mo producers undercut US efforts to establish a domestic supply. "We must achieve full cost recovery across the entire global commercial industry," he testified. "Any foreign government subsidy of HEU-based production puts the objectives of this legislation at risk."

David Kramer

A National Research Council committee identified flawed testing, faulty cost–benefit analyses, and other problems with the Domestic Nuclear Detection Office's program to develop and deploy improved radiation monitors for the screening of cargo at US ports. The NRC review also found that vendors of the Advanced Spectroscopic Portal (ASP) monitors had failed to deliver a system that meets DNDO's specification for modularity, with the result that the agency is unable to match the best-performing hardware with the optimal data-analysis algorithms, or to allow upgrades as experience is gained with the system.

The findings deal another blow to a program that has been bedeviled for years by performance issues. First planned as a replacement for the network of polyvinyl toluene (PVT) detectors that are currently installed at the nation's ports and border crossings (as shown here), the ASP system has since been relegated to a secondary role, scanning the shipping containers that set off the PVT portal monitors. The NRC panel, chaired by retired University of California president Robert Dynes, endorsed last year's determination by Department of Homeland Security secretary Janet Napolitano that ASP monitors haven't performed well enough to supplant PVTs. DNDO is a unit of DHS.

Ironically, the major motivator for ASP's development was the inability of PVT monitors to distinguish the radiation signatures emitted by threat materials, principally highly enriched uranium (HEU) or plutonium, from those of harmless, naturally occurring radioactive sources such as cat litter or bananas. As a result, PVT monitors at US ports are tripped hundreds of times each day by containers that pass through them. Each false alarm necessitates a secondary, time-consuming inspection by customs agents, who must clamber with handheld radiation detectors through the containers. Like ASPs, handhelds can identify the isotopic source of radiation.

More expensive, less effective

With a life-cycle cost of about $1.2 million each, ASP units are twice as expensive as PVTs, according to the NRC report. But tests have shown that ASPs, while better at detecting moderately shielded HEU, have performed worse than PVTs at uncovering plutonium or HEU that is masked by the radiation emanating from some other—possibly benign—radioactive material in the container. Noting that physical testing couldn't be carried out for every possible configuration of materials, nuclear contraband, and shielding inside shipping containers, the NRC reviewers recommended that DNDO add a significant modeling component to counter that limitation.

In performing its cost–benefit analysis of ASP, DNDO also should have considered the alternative of deploying improved versions of handheld detectors, known as radioisotope identification devices, that employ sodium iodide, germanium, or lanthanum bromide technologies, the committee said. Instead, DNDO's analysis dismissed RIIDs out of hand as unsuitable for external inspection of containers. Nor did it consider advances in RIID software that could improve their performance. According to DHS, advanced RIIDs would cost about $40 000 apiece over a 10-year lifetime, compared with $27 000 for current versions—well below the cost of either ASPs or PVTs.

The panel also admonished DNDO for the agency's ill-conceived effort to devise a single figure with which to summarize and compare ASP performance against other detection technologies. The number, or "figure of merit," was used as input to the ASP cost–benefit analysis, but it represented aggregated test data "in ways that are incorrect and potentially misleading," it said.

Congress had called for the NRC to review the ASP program in 2008, after acquisition of the new monitors was delayed several times over performance issues. The Government Accountability Office has produced several reports in recent years sharply critical of the ASP program, finding among other problems that vendors had inappropriately been involved in DNDO's qualification tests. Congress expressly forbade acquisition of the new monitors until after the DHS secretary personally certified ASP's readiness. In a May 2009 report, the GAO reported that the monitors "have a limited ability to detect certain nuclear materials at anything more than light shielding levels." That report also identified multiple problems with integrating ASPs into customs operations at US ports.

David Kramer

The New START treaty has finally cleared the Senate after a months-long campaign by the Republican leadership to kill it. Passage was finally assured when nine Republicans joined the Democrats to provide the two-thirds majority required to ratify the treaty and break a Republican filibuster.

Treaty ratification was a surprise win for the Obama administration, which for months had been trying to persuade Republican senators, notably Senate Minority Whip Jon Kyl of Arizona, to vote in support of New START. Both Kyl and Minority Leader Mitch McConnell (R-KY) voted against passage, along with 24 of their colleagues.

New START is the first arms control treaty to be ratified by the Senate in a lame duck session. The treaty would cut US and Russian strategic warheads by more than 30% and reintroduce, after a year without them, verifiable inspections of the remaining strategic warheads.

“Today’s bipartisan vote clears a significant hurdle in the Senate,” said Sen. John Kerry (D-MA), chairman of the Senate Foreign Relations Committee, shortly after the Senate voted to close debate. “We are on the brink of writing the next chapter in the 40-year history of wrestling with the threat of nuclear weapons.”

By last weekend, the Obama administration could count on six Republican senators to vote in favor of New START—senators Richard G. Lugar (R-IN), George V. Voinovich (R-OH), Susan M. Collins (R-ME), Olympia J. Snowe (R-ME), Lisa Murkowski (R-AK) and Scott Brown (R-MA). Only in the last few hours of Tuesday morning did the administration get word that other Republican senators, Lamar Alexander (R-TN), Johnny Isakson (R-GA), Bob Corker (R-TN), and Bob Bennett (R-UT), were willing to oppose the Republican leadership and vote in favor. At the last minute, Sen. Judd Gregg (R-NH) also joined those in favor of ratifying the treaty, although he missed the initial vote.

A sweet victory

The debate over New START was unusual, partly because the treaty itself was designed to be so uncontroversial—there are no new verification techniques in it beyond those in the expired START treaties, and the language of the treaty was written in such a way that the US could continue to develop and deploy missile defense systems.

Moreover, the Obama administration agreed to increase modernization funding of such nuclear weapons complexes as Los Alamos National Laboratory (LANL) to $84 billion over 10 years in order to assure the Republicans that the US wasn't weakening its nuclear defenses.

When Kyl announced in November that he wouldn’t support New START and that the Republicans needed more time to study the treaty, it came as a shock to Democrats. The treaty with Russia was signed in April, and more than 18 hearings had been held on it.

Unexpectedly, the Democrats, nudged by Vice President Joseph Biden, started a three-pronged effort led by President Obama, Sen. Kerry, and Secretary of State Hillary Clinton to gather enough support for passage by sidestepping party leadership and approaching Republican senators individually. Obama telephoned and lobbied senators throughout the process. Kerry and Clinton organized both a public and private campaign, which included getting the endorsement of current and former military leaders and the six living secretaries of state from Republican administrations, from Henry Kissinger through Condoleezza Rice. The final clincher appears to have been a weekend classified briefing for senators.

Despite the satisfaction that the administration can feel from today's success, the process provides a warning that further attempts to negotiate with Russia to disarm and dismantle the thousands of tactical nuclear warheads stockpiled by each side may be difficult, since the Republicans gain six seats in next year's Senate. "It is now clear that arms control is fair game in domestic politics and is no longer controlled by the foreign policy elites in either party," writes arms control analysts Nikolai Sokov and Miles A. Pomper of the vote.

The final step before New START goes into effect, ratification by the Duma, the Russian parliament, is expected in the next two weeks.

Paul Guinnessy

The New START treaty is under threat as Republicans in the Senate begin their campaign to make President Barack Obama a one-term president. The treaty would cut US and Russian strategic warheads by more than 30% and reintroduce verifiable inspections of the remaining strategic warheads after a one-year absence.

The administration had been negotiating with Senate Minority Whip Jon Kyl of Arizona who, in the Wall Street Journal last summer, demanded the modernization of such nuclear weapons complexes as Los Alamos National Laboratory (LANL) as part of the price to pass New START. Along with sending members of the Joint Chiefs of Staff to brief Kyl privately on why the military supported the treaty, the administration agreed to provide an additional $4.1 billion on top of the $80 billion modernization program. The program includes building at least two new nuclear weapons production facilities: the Chemistry and Metallurgy Research Replacement Nuclear Facility at LANL and the Uranium Processing Facility at Y-12 in Tennessee.

Last week, however, after consulting with the Republican leadership, Kyl announced that he thought the vote should not take place during the lame-duck session but should wait until the new term, when six new Republicans join the Senate. The move, which caught the administration by surprise, was widely seen as an attempt to kill the treaty. Currently at least nine Republicans are needed to ratify the treaty because New START requires 67 votes to pass the Senate. Kyl was the lynchpin to gain that support.

Push back

Instead of delaying the vote, as Minority Leader Mitch McConnell (R-KY) hoped, the administration decided to go on the offensive. Since last Wednesday, former and current senior officials—including Vice President Joe Biden, Secretary of Defense Robert Gates, Secretary of State Hillary Clinton, former Secretary of State Henry Kissinger, and Senator Richard Lugar (R-IN), who is the ranking minority member of the Senate Foreign Relations Committee—have been speaking out strongly in support of the treaty.

Sen. John Kerry (D-MA), chairman of the Senate Foreign Relations Committee, reemphasized the point that no inspections have been made of Russian facilities since the START II treaty expired in December 2009 and that not passing the treaty "would leave America in danger."

Kerry pointed out that the administration has answered more than 700 questions from senators about the treaty and that he has held 18 hearings on it. There is no reason not to vote in favor of this treaty, he said, and there is "no substantive disagreement" among senators over its validity. "Ratifying New START is not a political choice, it's a national security imperative," he added.

As part of its campaign for ratification, the administration has decided to approach Republican senators individually, instead of working with Kyl and the Republican leadership. The tactic may result in eight Republicans joining forces with Lugar to vote in favor, but it does have one high risk as the Republican leadership is keen to show a united front against any proposals from the Democrats: The administration might lose.

Paul Guinnessy

The recent announcement that nearly 20 kilograms of highly enriched uranium (HEU) in spent fuel was secretly shipped from a disused research reactor outside San Diego to a secure government facility for storage served as a reminder that considerable quantities of potentially weapons-usable material remain outside government control, including within the US. That is the case despite years of US and Russian efforts to reclaim the HEU that they provided decades ago to their allies for reactors and isotope production facilities.

On 8 November, the Department of Energy's National Nuclear Security Administration and the Nuclear Regulatory Commission announced they had completed the transfer of 19.7 kg of HEU spent fuel from an unspecified location in suburban San Diego to an undisclosed "secure federal facility."

Until the 1990s, General Atomics, a privately owned company, operated two of the eponymous TRIGA (Training, Research, Isotope, General Atomics) class of research reactors at its complex just inland of La Jolla. Both reactors are being decommissioned, and their spent fuel was scheduled to be removed from the premises during 2010, according to NRC's website.

The spent fuel was transported in three shipments during August and September, the agencies said, to a location about 1000 miles away. That distance corresponds to Idaho National Laboratory, where stainless steel–clad spent-fuel elements from other TRIGA reactors are in storage.

Since 2004 the NNSA's global threat reduction initiative (GTRI) has converted 22 HEU-fueled research reactors located in the US and abroad to operate with low-enriched uranium (LEU) fuel. That includes two reactors located in China and five Soviet-supplied reactors located in former Soviet states, in Eastern Europe, and in Libya. Six of the 32 operating US research reactors, all but one located at universities, have been converted by the NNSA during the same period.

According to the NNSA, the GTRI has converted or verified the conversion of 72 of the 200 research reactors that are within its "program scope." The World Nuclear Association says 230 such reactors in 56 countries are currently in operation. Another 361 reactors have been shut down or decommissioned, half of them in the US.

Rounding up HEU

Still, there clearly is much work to be done to round up the HEU that remains in civilian hands and make good on President Obama's April 2009 goal to secure all nuclear materials around the world within four years. A number of US reactors still operate with HEU, including at least two that are government-owned: NIST's Center for Neutron Research in suburban Washington, DC, and the High Flux Isotope Reactor at Oak Ridge National Laboratory. Some, like the ones at MIT and the University of Missouri, continue using HEU while awaiting the development of an LEU fuel that is tailored to their core configurations

The US shipped dozens of research reactors and HEU fuel to its allies beginning with the "atoms for peace" program in the 1950s. The commonly used fuel was enriched to 93% uranium—sufficient for a nuclear explosive. In 1978 with proliferation concerns growing, the US began research on retrofitting the reactors to run on low-enriched fuels. The US has also been accepting returns of US-origin HEU fuel.

The NNSA has also been striving to secure Soviet-origin weapons-usable materials—from all sources. On 18 November the agency announced that it had completed the shipment of 10 metric tons of HEU and 3 tons of plutonium—enough to make 775 nuclear weapons, it said—from the Soviet-built BN-350 fast reactor in Aktau, Kazakhstan, to a secure storage site in the northeastern part of that country, home to the former Soviet nuclear test site Semipalatinsk.

The material was placed into 60 specially fabricated casks and shipped more than 3000 km on specially built railcars. The US paid $219 million for the operation, while the UK contributed $4 million, according to published reports. The year-long operation also required the construction of new railroad track.

Located on the eastern shore of the Caspian Sea, the BN-350 was designed to both generate electric power and breed plutonium for the Soviet nuclear weapons program. It was shut down more than a decade ago, and a temporary storage site was built with US help. The BN-350 cache dwarfs the 1479-kg total Soviet-origin HEU fuel, both fresh and spent, that the NNSA had previously secured by returning it to Russia. In most cases, the US has paid the entire cost for packaging and transportation of the material, according to the NNSA.

David Kramer

Department of Energy undersecretary Steven Koonin has tapped David Crandall, the chief scientist at DOE's National Nuclear Security Administration, to devise a program for developing inertial fusion as an energy source.

In his new position, Crandall "will facilitate cooperation and collaboration between NNSA and the Office of Science, which are key to advances in inertial fusion energy," according to a memorandum from NNSA administrator Thomas D'Agostino. In an interview last year with Physics Today, Koonin said he planned to step up research toward the use of inertial fusion for electricity generation. In particular, Koonin pointed to the National Ignition Facility, which was built for inertial fusion experiments in support of the nuclear weapons program, as offering an alternative to the magnetic confinement approach embodied in ITER, the international prototype fusion reactor under construction in France.

D'Agostino named Dimitri Kusnezov, director of research and development for national security science and technology, to replace Crandall as chief scientist.

David Kramer

President Obama's top adviser on preventing nuclear terrorism has declared Pakistan to be his biggest source of concern. Gary Samore serves as special assistant to the president and White House coordinator for arms control and weapons of mass destruction, proliferation, and terrorism. He told an audience at the American Association for the Advancement of Science that the possibility of Pakistan losing control of a nuclear weapon is "the thing that keeps me up at night." With Pakistan's unstable government intending to expand its nuclear weapons program, he warned on 19 October, "things could go bad very quickly in South Asia." But the US has "extremely limited policy tools" to wield in attempting to defuse the threat Pakistan presents, he admitted.

Despite that assessment, Samore said he spends most of his time dealing with Iran's nuclear program, which the US and its allies maintain is focused on nuclear weapons. Economic sanctions imposed by the UN have "probably slowed [Iran's] program down by a few years," he said. The discovery of a second, secret underground uranium enrichment facility in Iran "shook up" Russia and convinced the formerly skeptical nation that its neighbor to the south has nuclear weapons ambitions, he said.

Samore went on to say that persuading existing nuclear weapons states to give up their arsenals will not be possible as long as sovereign nations view them as essential to deterrence and defense. Until then, world powers must prevent the further spread of fissile material production technologies to nations such as Iran. Countries with the capability to produce nuclear fuel should supply reactor fuel to countries that aspire to generate nuclear energy, as the US will do under a recently signed bilateral agreement with the United Arab Emirates.

The world was "extraordinarily lucky" that neither nuclear weapons nor significant amounts of fissile material got into the hands of terrorists following the collapse of the Soviet Union, Samore said. Except for "a couple of cases" in the early 1990s involving kilogram quantities of highly enriched uranium (HEU) and plutonium from former Soviet states, which were broken up by police, the vast majority of nuclear smuggling incidents have been "bogus," he said.

David Kramer

The UK government, which consists of a coalition between the Conservatives and the Liberal Democrats, is split on how to handle the future of the UK's nuclear deterrent. Currently the system consists of 58 nuclear-armed Trident II D-5 ballistic missiles that are carried on four Vanguard-class submarines. One submarine remains on patrol at all times.

Each Trident missile contains between three and ten nuclear warheads that have a yield between 10 and 100 kilotons. Under the previous Labour government's plan, three of the four submarines would be replaced in the early 2020s.

In the run-up to this year's general election, the Liberal Democrats campaigned on getting rid of the Trident system, whereas the Conservatives supported upgrading and modernizing the UK's nuclear deterrent.

Recently, the coalition government announced that they were going to defer the question over what to do about Trident until after the next election, which must be held by May 2015. The government opted for the delay partly for budgetary reasons and partly because of the stress any decision would put on its stability.

Threats to UK science

The government has resolved, however, that its next budget will include cuts of 20–25% in funding for scientific research. In response, a group of 36 scientists has written to Prime Minister David Cameron urging his administration to scrub the UK's nuclear deterrent and invest the savings in civilian science.

Specifically, the scientists, who include ex-Royal Society president Michael Atiyah and Nobel Prize winner Harold Kroto, propose that the nuclear warheads be taken off the Vanguard submarines and put into storage; plans for an updated deterrent should be scrapped entirely.

The UK government currently spends £8 billion (US$12.8 billion) on R&D, of which 25% (US$3.2 billion) is spent on defense projects. "Much of this funding is used to support defence industry projects at a time when the industry is reaping bumper profits due to the massive increase in global military expenditure over the last decade," say the scientists in their letter to the prime minister.

Replacing Trident is still someways off. However, to keep staff at the Atomic Weapons Establishment (AWE), which manages the UK warheads, up-to-date with techniques for modernizing and maintaining the warheads, the Ministry of Defence decided last year to spend an extra $1.6 billion annually over the next three years on the UK's three most powerful supercomputers (two codenamed Willow; one codenamed Blackthorn) and on a new hydrodynamics facility (codenamed Hydrus) that will conduct stockpile stewardship experiments.

"It's completely irrational to cut scientific research into medical and environmental problems," says Stuart Parkinson, executive director of Scientists for Global Responsibility, who coordinated the letter, "whilst pouring billions of pounds of research money into facilities for designing new nuclear warheads."

Does the UK need nukes?

"The major security threats we will face in the coming years have their roots in problems like climate change and resource shortages," says Parkinson. "These are the areas where more of our research should be focused, and yet the UK currently devotes 20 times more research funding to military projects than to renewable energy. If cuts have to come, it's clear to us that [AWE] is where the axe should fall."

Moreover, in their letter to the prime minister the scientists argue that by keeping its nuclear deterrent the UK is undermining progress toward multilateral nuclear disarmament, despite being a signatory to the Treaty on the Non-Proliferation of Nuclear Weapons. They write:

These developments are going ahead despite serious questions existing about the future of the UK's nuclear weapons program and a recent pledge by President Obama that the US will not develop new nuclear warheads.

We therefore urge ministers to shift their priorities so that science and technology can contribute to tackling the real threats to the UK's present and future security.

Paul Guinnessy