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!NEW PUBLICATION! in Progress in Nuclear Energy by F. Frieß and W. Liebert

Symbolic picture: PublicationsInert-matrix fuel for transmutation: Selected mid- and long-term effects on reprocessing, fuel fabrication and inventory sent to final disposal

by F. Frieß and W. Liebert

Abstract:
Partitioning and transmutation (P&T) fuel cycles provide a technical approach to ease the problem of radioactive waste disposal. Some of the partitioned components of the waste stream are irradiated while others can be used for energy production or are sent to final storage. Minor actinides are planned to be irradiated in a fast spectrum nuclear facility to transmute them into stable or short-lived isotopes. As minor actinides have negative effects on reactor dynamics, subcritical, accelerator-driven systems are proposed to increase their fraction in the fuel. An example is the MYRRHA research reactor to be built in Mol, Belgium.

This reactor is modeled for depletion calculations. The behavior of special fuel elements that mirror fuel composition as envisioned for large scale transmutation facilities, namely inert-matrix fuels with an increased minor actinide content, are investigated within this reactor environment. It turns out that gamma dose rates, activity and residual heat from the spent fuel elements present significant challenges for implementing a P&T program. Spent inert-matrix fuel element show significantly higher levels than spent fuel elements from fast reactors. This requires long cooling periods and poses unprecedented challenges to reprocessing technology. The problem is amplified by the fact that it is generally agreed upon that due to low transmutation efficiencies several transmutation steps would be necessary. Looking at the radiotoxicity index, the efforts suggested to reduce the minor actinide content in a final repository are justified. The long-term safety case of deep geological repositories, however, implies that certain long-lived fission products are more relevant. The build-up of some of these radionuclides is investigated for two hypothetical German P&T scenarios. Naturally, the amount of fission products increases with continued irradiation. But namely the fraction of Cs-135 increases over-proportionally when inert-matrix fuel rich on minor actinides is used.

The Paper can be found here: https://www.sciencedirect.com/

NEW PUBLICATION: First publication of an ecological vulnerability analysis for the application of a gene drive in a wild insect population!

Carina R. Lalyer published an article titled “Ecological vulnerability analysis for suppression of Drosophila suzukii by gene drives” in the journal Global Ecology and Conservation.


Drosophila suzukii
has been increasingly emerging as an invasive species and agricultural pest in recent decades. It describes a framework for assessing potential ecological impacts and the consequent vulnerability of ecological systems that could result from the release of genetically modified organisms. Such impacts depend on the biology and ecology of the organism but also on the type of gene drive used. The work illustrates reasons for concern and uncertainties when dealing with such a technology. Specific potential effects of the Drosophila suzukii fruit fly were further investigated to assess the vulnerability of related species or parasites.

This work represents the first ecological vulnerability analysis for the application of a gene drive in a wild insect population.

The article is open access and freely available at:
https://doi.org/10.1016/j.gecco.2021.e01883

carina.lalyer(at)boku.ac.at

The Viral Era

Bernd Giese recently published an article titled “The viral era” in EMBO reports under the category ‘Science & Society’. He discusses the developments of modern technologies away from direct human influence towards increasingly autonomous systems. The article illustrates several bio-control techniques, from sterile insect technique (SIT), to gene drives, to viral applications such as Horizontal Environmental Genetic Alteration Agents (HEGAA). The article concludes with a call for adequate safeguards and asking whether our understanding of nature is sufficient for comprehensive management of ecological and socio-ecological systems.

The article is freely available under open access policy at embopress.org.