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(First of a series)
Jonathan Medalia is a specialist in nuclear weapons policy for the Congressional Research Service in Washington.
It was Medalia’s job last week to address those in attendance at the Nuclear Deterrence Summit in Washington.
Thinking Inside the Boxes: Can Existing Buildings Meet Department of Defense’s Pit Needs?
Needless to say, Los Alamos came up often during Medalia’s talks.
First Medalia gave a little history.
“As most of you know, a pit is a hollow plutonium shell. When imploded by conventional explosives, the energy from the resulting nuclear explosion detonates the rest of the weapon. During the Cold War, the Rocky Flats Plant made pits on an industrial scale, sometimes over 1,000 per year. Rocky Flats ceased production in 1989. Since then, the U.S. has been unable to make more than about 10 pits per year (ppy), and post-1989 attempts to produce pits at a higher rate have failed. Yet DOD says it needs 50 to 80 ppy by 2030 in order to extend the life of certain types of nuclear weapons,” he said.
“There’s a debate on the need for 80 ppy. But my focus is on a topic that hasn’t been debated: how could the US produce pits at the maximum rate DOD says it needs, 80 per year?
“The takeaway is that some options may permit reaching that capacity by using existing buildings, at relatively modest cost and schedule, with minimal environmental impact, or by using new, smaller, less costly buildings.”
Medalia then got talking about the Los Alamos National Laboratory where pit production is done in PF-4, which opened in 1978.
“ It has a foundry and other equipment for making pits. It also houses other plutonium projects, such as a Pu-238 line, the ARIES line for turning pits into plutonium oxide, a line for recovering plutonium from nitric acid solution, plutonium R&D, and some AC. Most AC is done in the Chemistry and Metallurgy Research Building, CMR, operational since 1952. One report called it “genuinely decrepit”; another called it “structurally unsound.” It is seismically fragile. The National Nuclear Security Administration (NNSA) wants to exit CMR by 2019.”
Then Medalia discussed two pit production options.
“One would use new buildings called modules; the other would use existing buildings. There are no unclassified sketches of a module.
“Modules would be reinforced-concrete structures for such high-MAR tasks as pit fabrication and Pu-238 work. They offer several potential advantages.
“Large buildings have been rejected repeatedly; modules would be smaller, less costly, and more likely to receive support. Indeed, Congress authorized NNSA to pursue this strategy in the FY2014 National Defense Authorization Act.
“Each module would be designed for a single task, so would not have to meet regulatory requirements imposed by other tasks. On the other hand, there are questions about the need for modules, given other options; whether they are needed now; and how much they would cost.
“Note that even if a pit foundry and Pu-238 work were moved into modules, space would still be needed outside of PF-4 for AC because it would be very difficult to reconfigure PF-4 to perform most types of AC efficiently, especially for a capacity of 80 ppy. Nor would modules be cost-effective for AC, which is low-MAR, since they would be designed for high-MAR work.”
On Tuesday, Medalia will talk about existing buildings and how they may work in developing pit production.
• MAR, which stands for Material At Risk. This is the aggregate amount of radioactive material of all types permitted in a building.
• Hazard Category (HC). The standard to which a plutonium building must be designed depends on the amount of Pu-239E it is intended to hold
• Radiological Facility. Some buildings, such as some labs, are expected to hold only a small amount of radioactive material, 38.6 g of Pu-239E or less.
• Buildings are also rated by Security Category (SC) based on the attractiveness of the material, especially to terrorists. Buildings with weapons, or with more than 2 kg of weapons-grade plutonium, are in SC-I and require elaborate security measures. At the other end of the spectrum, SC-IV buildings hold low-grade material, which is less attractive to terrorists. As a result, less stringent security measures suffice.
• Analytical Chemistry (AC) supports pit production. It determines the isotopic composition, and amount and type of impurities, in plutonium samples from pits
• Plutonium-238 (Pu-238) is an isotope of plutonium. It is 275 times more radioactive than Pu-239 and glows red hot. It is used to power space probes. It is not suitable for pits. Pu-238 in quantities less than 16 kg is high-MAR but low-SC.