NSUF 15-548: Isotopic ratio measurements in MANTRA irradiated samples
Neutron cross sections are essential to most nuclear engineering projects and, even though theoretical progress has been made as far as the predictability of neutron cross-section models, measurements are still indispensable to meet tight design requirements for reduced uncertainties. In particular, the assessment of advanced fuel cycles requires an extensive knowledge of transuranics cross sections. Plutonium isotopes, but also Americium, Curium and up to Californium isotope data are required with a small uncertainty in order to optimize significant features of the fuel cycle that have an impact on feasibility studies (e.g. neutron doses at fuel fabrication, decay heat in a repository etc.). The MANTRA project aims to obtain valuable integral information about neutron cross sections for actinides that are important for advanced nuclear fuel cycles. Its principle is to irradiate very pure actinide samples in the Advanced Test Reactor at INL and, after a given time, determine the amount of the different transmutation products. The determination of the nuclide densities before and after neutron irradiation will allow inference of effective neutron capture cross-sections. The list of actinides that have already been irradiated is the following: Th-232, U-233, U-235, U-236, U-238, Np-237, Pu-239, Pu-240, Pu-242, Pu-244, Am-241, Am-243, Cm-244 and Cm-248. The list of fission products is the following: Sm-149, Eu-153, Cs-133, Rh-103, Ru-101, Nd-143, Nd-145 and Pd-105. In order to obtain effective neutron capture cross sections corresponding to different neutron spectra, three sets of actinide samples have already been irradiated: the first one is filtered with cadmium and the other two are filtered with enriched boron of different thicknesses (5 mm and 10 mm). The cadmium-filtered and the 5-mm-boron-filtered irradiations were completed in January 2013 after, respectively, 55 days and 110 days in the reactor. The last irradiation with the 10-mm boron filter was completed in January 2014 after 110 days in the reactor. After a cool-down time in the ATR canal, the baskets containing the irradiated samples were transported to the hot cells of the Hot Fuel Examination Facility (HFEF) located at the Materials and Fuels Complex (MFC) where they were dismantled. The vials containing the samples were then sent to the nearby Analytical Laboratory for further analyses using the new MC-ICP-MS which was brought online in April 2013. As of today, the MC-ICP-MS analyses have been completed for the samples irradiated with the 5-mm-boron filter and with the cadmium filter. The MC-ICP-MS measurement campaign was very successful with about 65 samples (initial + irradiated) characterized in a relatively short period of time. All the isotopic ratios of interest have an associated 2-sigma uncertainty comprised between 0.5% and 1% which was what was requested. ATR as-run physics calculations using MCNP are also underway and the comparison of the measured ratios with the results of these first MCNP calculations showed larger discrepancies than expected. In this respect it is very important to also have the isotopic ratios in the samples irradiated with the 10-mm-boron filter. Consequently, the objective of this RTE proposal is to finalize the MC-ICP-MS analyses for the samples irradiated with the 10-mm-boron filter. Worthwhile mentioning, the MANTRA experiment was presented to the recently established Organization for Economic Cooperation and Development (OECD) Nuclear Energy Agency (NEA) Expert Group on Improvement of Integral Experiments Data for Minor Actinide Management. The international scientific community has shown its strong interest for such activity and is currently considering the establishment of a large international collaboration under the NEA umbrella, to pool together experiments of different types in different experimental facilities in the world to enlarge the scope of the research. MANTRA, if successful, could give INL, a leading role in such collaborative research.
Additional Info
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| Abstract | Neutron cross sections are essential to most nuclear engineering projects and, even though theoretical progress has been made as far as the predictability of neutron cross-section models, measurements are still indispensable to meet tight design requirements for reduced uncertainties. In particular, the assessment of advanced fuel cycles requires an extensive knowledge of transuranics cross sections. Plutonium isotopes, but also Americium, Curium and up to Californium isotope data are required with a small uncertainty in order to optimize significant features of the fuel cycle that have an impact on feasibility studies (e.g. neutron doses at fuel fabrication, decay heat in a repository etc.). The MANTRA project aims to obtain valuable integral information about neutron cross sections for actinides that are important for advanced nuclear fuel cycles. Its principle is to irradiate very pure actinide samples in the Advanced Test Reactor at INL and, after a given time, determine the amount of the different transmutation products. The determination of the nuclide densities before and after neutron irradiation will allow inference of effective neutron capture cross-sections. The list of actinides that have already been irradiated is the following: Th-232, U-233, U-235, U-236, U-238, Np-237, Pu-239, Pu-240, Pu-242, Pu-244, Am-241, Am-243, Cm-244 and Cm-248. The list of fission products is the following: Sm-149, Eu-153, Cs-133, Rh-103, Ru-101, Nd-143, Nd-145 and Pd-105. In order to obtain effective neutron capture cross sections corresponding to different neutron spectra, three sets of actinide samples have already been irradiated: the first one is filtered with cadmium and the other two are filtered with enriched boron of different thicknesses (5 mm and 10 mm). The cadmium-filtered and the 5-mm-boron-filtered irradiations were completed in January 2013 after, respectively, 55 days and 110 days in the reactor. The last irradiation with the 10-mm boron filter was completed in January 2014 after 110 days in the reactor. After a cool-down time in the ATR canal, the baskets containing the irradiated samples were transported to the hot cells of the Hot Fuel Examination Facility (HFEF) located at the Materials and Fuels Complex (MFC) where they were dismantled. The vials containing the samples were then sent to the nearby Analytical Laboratory for further analyses using the new MC-ICP-MS which was brought online in April 2013. As of today, the MC-ICP-MS analyses have been completed for the samples irradiated with the 5-mm-boron filter and with the cadmium filter. The MC-ICP-MS measurement campaign was very successful with about 65 samples (initial + irradiated) characterized in a relatively short period of time. All the isotopic ratios of interest have an associated 2-sigma uncertainty comprised between 0.5% and 1% which was what was requested. ATR as-run physics calculations using MCNP are also underway and the comparison of the measured ratios with the results of these first MCNP calculations showed larger discrepancies than expected. In this respect it is very important to also have the isotopic ratios in the samples irradiated with the 10-mm-boron filter. Consequently, the objective of this RTE proposal is to finalize the MC-ICP-MS analyses for the samples irradiated with the 10-mm-boron filter. Worthwhile mentioning, the MANTRA experiment was presented to the recently established Organization for Economic Cooperation and Development (OECD) Nuclear Energy Agency (NEA) Expert Group on Improvement of Integral Experiments Data for Minor Actinide Management. The international scientific community has shown its strong interest for such activity and is currently considering the establishment of a large international collaboration under the NEA umbrella, to pool together experiments of different types in different experimental facilities in the world to enlarge the scope of the research. MANTRA, if successful, could give INL, a leading role in such collaborative research. |
| Award Announced Date | 2015-04-22T00:00:00 |
| Awarded Institution | None |
| Facility | None |
| Facility Tech Lead | Alina Zackrone |
| Irradiation Facility | None |
| PI | Gilles Youinou |
| PI Email | [email protected] |
| Project Type | RTE |
| RTE Number | 548 |