Comments about technological history, system fractures, and human resilience from James R. Chiles, the author of Inviting Disaster: Lessons from the Edge of Technology (HarperBusiness 2001; paperback 2002) and The God Machine: From Boomerangs to Black Hawks, the Story of the Helicopter (Random House, 2007, paperback 2008)

Tuesday, January 25, 2011

Stuxnet, Iran & SCADA: Compiling the unanticipated consequences

Amid the high-fiving and knuckle-bumping over Stuxnet and the havoc it wrought on the Iranian uranium-enrichment effort at Natanz, a few commentators have brought forward worries about two possible unintended consequences. I'll add a third.

First, a recap of what Stuxnet apparently did. After somebody inserted it into the Siemens-provided SCADA (supervisory control and data acquisition) system used at Natanz, Stuxnet caused some centrifuges to go beyond their red-line limits and break up. 

Not all the Iranian centrifuges were destroyed but it was a big setback. Because operators in the control room normally would have learned from their instruments that this situation was developing early enough to head off the damage, Stuxnet also used a man-in-the-middle attack. Meaning: while things were coming apart, fake data sent to the control room said everything was fine.

One concern already expressed is that the “wrapper” around Stuxnet was rather carelessly put together as far as concealing its creators (news reports suggest the US led off the effort, followed by Israel), and thus could invite a new front in a cyber war. China is no doubt miffed because its factories were affected also.

A second concern is that the West will get complacent about watching the Iranian program. According to the Tehran Times, Iran will forge ahead with enrichment, stux-bugs or no.

My concern: assuming that Iran now harbors serious doubts about its centrifuges, it might resume the work it suspended a few years ago on laser isotope enrichment, or LIS. Unfortunately, it could be a game-changer.

The first revelation of Iran's interest came in August 2002, when the dissident group National Council of Resistance of Iran announced at a Washington, D.C., press conference that Iran had built a laser enrichment facility at Lashkar Ab'ad. After being discovered, Iran allegedly dismantled its LIS gear in 2003.

Why does it matter? If rogue states master the technology, LIS radically increases the risk of nuclear proliferation. To summarize the main points:
  • As is well known, it's a lot easier to build a uranium bomb than a plutonium one ... but only after the fissionable material is in hand;
  • Fortunately for our peace of mind, it's been very difficult to enrich uranium to sufficient levels for bomb use. This has served as a firewall to proliferation;
  • But LIS holds the promise of enriching uranium with small-scale, concealable facilities. Therefore IAEA inspectors will find it very hard to find LIS-equipped enrichment facilities, and if they find them, to know for sure what the facilities are producing;
  • So if LIS gets into general circulation, the last significant barrier to nuclear weapon proliferation among rogue states will fall.
The long, slow rise of LIS has been something the press has mostly ignored, concentrating instead on rogue states' banks of gas centrifuges. Maybe it's because gas centrifuge hardware for uranium enrichment has long been established, and is easily visualized and understood. Gas centrifuges for uranium hexafluoride gas are so specialized that inspectors can spot them right away, once they get inside the facility.

LIS by contrast will be very hard to detect. Fortunately, so far, it is only in early emergence stage when it comes to producing highly-enriched uranium that's suitable for nuclear weapons (generally, this is understood to mean the ratio of U-235 isotope is 80% or more, though the percentage could be significantly less). LIS is already feasible enough for GE Hitachi to propose commercializing it to feed a new wave of power reactors. China is building more than 20 nuclear reactors now.

American research opened this Pandora's box. In 1985 Lawrence Livermore National Laboratory developed the laser separation technique, and announced it to the world as a cost-cutting breakthrough in production of reactor fuel that would enable us to cut our prices for fuel being sold to American and foreign power reactors, far below what had been possible with gas centrifuges, a concept dating to the Manhattan Project.

At the time the U.S. was losing business to centrifuge plants in Europe that were undercutting its aging, energy-wasting gas-diffusion plants in Kentucky, Tennessee, and Ohio. Said an assistant secretary at the Department of Energy: ''This is the way of the next century. It's the world's best way of enriching uranium.''

There are three common methods of laser separation now, but the most developed (and the one Iran has taken an interest in) is called atomic vapor laser isotope separation, or AVLIS. This was the approach developed by Lawrence Livermore.

Here's how AVLIS works. First electron beams produce uranium gas from a slab of unenriched metal. Then a two-stage laser goes to work. The first stage is a high-power copper-vapor laser, which sends blue light over to a dye laser. The dye laser sends red-orange light of an extremely precise wavelength into a cloud of uranium atoms. If tuned with great precision the laser will knock outer-shell electrons off U-235 atoms but not U-238 atoms, because their masses are slightly different. The laser causes the U-235 atoms to become positive ions and fling themselves against a negatively-charged metal plate for removal later. It’s necessary to send the enriched vapor through six stages to bring it to weapons purity.

If this sounds impossibly high-tech for a rogue nation or group, it’s not. 
Worldwide, hundreds of university and government labs already use laser-separation equipment. Usually it’s for peaceful research purposes, but not always. Several labs, including one at Taejeon, South Korea, already have used laser separation to make a few hundred milligrams of weapons-grade uranium.

The IAEA shut down the Republic of Korea’s effort in 2004 after discovering that wisp of enriched fuel but in most cases it’s going to be very difficult to know whether a given set of AVLIS equipment is part of a concealed weapons program or something legitimate. That’s because certain high-tech industries, such as electronics, need certain metals of great isotopic purity, just like nuclear weapons manufacture does, and laser isotope separation is an accepted way to obtain it. So confirming the existence of weapons-purposed AVLIS equipment will be greatly more difficult than spotting high-speed centrifuges for corrosive uranium hexafluoride gas, which are unique and immediately recognized by weapons inspectors.

While it would take dozens of AVLIS machines to make enough material for one bomb a year, the machines are compact enough so that all of them would fit inside the floor space equal to a big-box discount store, and therefore would not be difficult to conceal in tunnels underground. 

If and when AVLIS machines are set up for making weapon-grade uranium, they're most likely to go into tunnels under existing military bases. It's common for military bases to have underground storage.

The pace of LIS is likely to accelerate with advances in industrial lasers, which each year have been dropping in price while going up in efficiency and precision. According to some experts, the eventual spread of AVLIS is as obvious as the spread of advanced chip-manufacturing techniques for computers, which showed up in many nations after a few companies worked out the essential details. 

This suggests to me that anti-nuke-smuggling measures, and (for the worst-case scenarios) forensic analysis, are still timely.

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