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Nuclear Archaeology

Nuclear archaeology is an ensemble of scientific methods aimed at reconstructing past operation of nuclear facilities and improving our understanding on the past production of nuclear materials for military purpose. These methods use on-site measurements of specific indicators from which information on the past operation of the facility can be inferred. Most often, these indicators are specific isotopes' concentration or ratios of them in structural materials or waste where the production process has left its fingerprint. First, the facility past operation must be modelled in order to predict the evolution of chosen indicators. In the second phase, these indicators are measured on-site and their values are compared to the modelled predictions. This comparison allows us to gain more information on specific parameters of the past operation of the facility such as the burnup level of nuclear reactors or the separative power of enrichment plants. Methods of nuclear archaeology can offer rigorous and effective tools to verify baseline declarations of historic nuclear materials production.



The same reactor can be used to produce plutonium or tritium. Not knowing which materials was produced in a reactor prevents accurate estimates on past production. This work presents the first scientific methods to deduce whether a reactor was used in a plutonium production or tritium production mode. Changes in the fuel arrangements between production modes induce changes in the physics of the reactor which are reflected in certain isotope ratios. Measuring these isotope ratios allows to deduce the past production mode of a reactor.

Verifying Nuclear Reactors' Production Modes

Collaborators on this project: Alexander Glaser, Malte Göttsche

Publication: J. de Troullioud de Lanversin, M. Göttsche, A. Glaser, “Nuclear Archaeology to Distinguish Plutonium and Tritium Production Modes in Heavy-Water Reactors,” Science & Global Security, 26 (2018)


North Korea has been using its graphite-moderated, gas-cooled 5-MWe reactor to produce plutonium for its nuclear arsenal since 1986. Nuclear archaeology can help verify historical production of plutonium in the 5-MWe reactor. Specific isotope ratios in the graphite moderator can be measured to infer the fluence level of the reactor which, in turn, can be related to plutonium production. In this project, ONIX is used to identify the few isotope ratios that can be used today to estimate historical plutonium production in the 5-MWe reactor.

Nuclear Archaeology for North Korea's 5-MWe Reactor

Collaborators on this project: Moritz Kütt

After irradiation in a nuclear reactor, plutonium can be extracted from the spent fuel via reprocessing. Reprocessing generates waste which are stored in high-level waste tanks. The isotopic composition of the waste is characteristic of the design and operation of the reactor used to irradiate the spent fuel. This work looks at possible methods to infer the burnup levels of spent fuel by measuring isotopic concentrations from reprocessing wastes.


Estimating Past Plutonium Production with Reprocessing Waste

Collaborators on this project: Malte Göttsche (lead), Holger Tietze-Jaesch

Publication: M. Göttsche, J. de Troullioud de Lanversin, Holger Tietze-Jaensch, “Examining Reprocessing Waste to Help Estimate Past Plutonium Production,” 58th Annual INMM Meeting, Indian Wells, California, July 17-21

Methods of nuclear archaeology can offer very powerful tools to verify past nuclear materials production. However, many source of uncertainties at different stages in the implementation of these methods can reduce their practicability. This includes uncertainties on past operation of the facility, on the design, approximations made in the numerical model, computational errors, or uncertainties in isotope ratios measurements. This project intend to make an exhaustive review of these uncertainties and qualitatively assess their impacts.


Understanding Uncertainties in Nuclear Archaeology 

Collaborators on this project: Moritz Kütt, Malte Göttsche

Publication: M. Kütt, J. de Troullioud de Lanversin, M. Göttsche, “Understanding Uncertainties in Nuclear Archaeology,” 59th Annual INMM meeting, Baltimore, MD, July 22-26

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