Month: June 2014

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Minor Uranium Isotopes in Enrichment Tails

Originally for my project this summer I wanted to try to model the IR-40 pressurized heavy water reactor (PHWR) to test if the thermohydraulics of the reactor were still sound even at an enrichment level different from the natural uranium design. Ultimately my project was changed and now I am going to be researching minor uranium isotopes. These are a few brief comments on what I hope to learn and accomplish from this research project.

Uranium enrichment today is done one of two major ways, gaseous diffusion and centrifugation. These two processes take uranium in the gaseous uranium-hexaflouride form (UF6) and use the (slight) mass difference between uranium 235 (U-235) and uranium 238 (U-238) to separate the isotopes and enrich the percentage of U-235 per unit mass of total uranium metal. The significance of this information is that in nature another isotope exists: U-234. This isotope due to being significantly smaller than the U-238 atoms, tends to “stick” with the U-235 during enrichment. In reprocessed uranium fuel several different isotopes are created through irradiation and decay. These include U-232, U-233, and U-236 in addition to the U-234 already present in the system. While these isotopes increase the complexity of the system when it comes to separation for enrichment, they have potential nuclear forensic applications.

In binary systems and models we would only deal with separating U-235 and U-238, unfortunately this is an oversimplified model given the previously stated information. In order to more accurately and realistically model the enrichment of natural or reprocessed uranium a model must be used that takes into account the multiple species that are present in the system. Using this information I aim to answer if it is possible to use the minor isotopes to determine the enrichment capabilities of a state and can it be attributed to a state in the case of smuggled material all by the concentrations of the minor isotopes in either the product stream or the tails. In order to do so I am researching mathematical models of isotope enrichment per stage in a cascade and computing the separation factors of each species and unit.

Ultimately I aim to assess the feasibility of using these minor isotopes as a “forensic fingerprint” by identifying the separation processes and the effects the different feeds can have in the minor isotope concentrations at different parts of the enrichment cycle.

-Cervando Banuelos is currently a Nuclear Safeguards Intern at Lawrence Livermore National Laboratory, a Graduate Research Assistant at the Monterey Institute of International Studies where he is currently pursuing a master’s of arts in nonproliferation and terrorism studies, and holds a bachelor’s of science degree in nuclear engineering, with a minor in radiological health engineering, from Texas A&M University. His interests include passive cooling systems in boiling water reactors, nuclear forensics, arms control treaties, treaty verification, and steaks wrapped in bacon. He hopes to some day work for the United Nations, a national laboratory, or the CTBTO.

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Nuclear Safeguards Course Day 1

I am currently attending the International Nuclear Safeguards Policy and Information Analysis Course at the Monterey Institute of International Studies also co-sposnsored by the U.S. Department of Energy’s National Nuclear Security Administration (NNSA), the James Martin Center for Nonproliferation Studies (CNS), and Lawrence Livermore National Laboratory (LLNL).

Yesterday was day 1 of the course, and for 8 hours we sat and listened to experts outline the origins of safeguards, the foundations of the Nonproliferation Treaty safeguards (NPT), facility-level safeguards implementation, and even got to play with some of the equipment an IAEA inspector would use at a site inspection.

I just want to take a few lines and outline a few points that I find interesting to the research work I have done at CNS, and that I hope to incorporate into the research project I plan to undertake at LLNL this summer as an intern.

During the first presentation we discussed and dove into the different statutes of the International Atomic Energy Agency (IAEA) to understand the nature and origins of safeguards as outlined by the international community. Here I realized the explicit purpose of safeguards is not to prevent the diversion of nuclear technology from peaceful uses, but rather the detection of said diversion. This is an interesting view that I had never realized and why it leads to some states to be “sneaky” about going about their clandestine nuclear programs. What I also learned was that despite this, safeguards do in fact deter diversion indirectly. Nobody likes to get caught redhanded breaking a big treaty like the NPT, so the risk of being caught diverting material deters the diversion of material. This goes on to show the power and need for nuclear safeguards.

When we reviewed the history and foundation of the NPT safeguards, I learned about the bilateral safeguards agreements that started during the early days of the atomic era where one nuclear state would share the technology to an allied state it trusted to not divert from peaceful uses. This presented a problem since it left out non-allies and left many partnerships that had no security assurances over others and that were vulnerable to changes in governance of the state, such as the case with the Iranian Revolution. These bilateral arrangements led to the first nuclear weapons free zone under the first nonproliferation treaty, not a misuse treaty. The Treaty of Tlatelolco (1967) provided nuclear negative security assurances between states and states with territories in the South American and Caribbean region after Brazilian and Argentinian interests in nuclear technology, and was a landmark for nuclear safeguards and eventually the NPT regime.

These two thoughts stuck with me and I made sure to make a specific note on them. The whole course has been going quite well and we still have 4 days to go through, with case studies, activities, and discussions where we will review the challenges of safeguards to the 21st century and how they apply to nuclear security.

 

-Cervando Banuelos is currently a Nuclear Safeguards Intern at Lawrence Livermore National Laboratory, a Graduate Research Assistant at the Monterey Institute of International Studies where he is currently pursuing a master’s of arts in nonproliferation and terrorism studies, and holds a bachelor’s of science degree in nuclear engineering, with a minor in radiological health engineering, from Texas A&M University. His interests include passive cooling systems in boiling water reactors, nuclear forensics, arms control treaties, treaty verification, and long walks on the beach. He hopes to some day work for the United Nations, a national laboratory, or the CTBTO.

 

The views expressed within this op ed piece DO NOT in any way, shape, or fashion reflect the opinion or views of the Monterey Institute of International Studies, the James Martin Center for Nonproliferation Studies, the NNSA, nor Lawrence Livermore National Laboratory. The above statements are only the reflections of the author and his experiences.