Forensic Measurements for Nuclear Archaeology: Insights from Trawsfynydd Revisited
Explore the fascinating field of nuclear archaeology with a focus on Trawsfynydd, delving into topics such as fissile material declarations, plutonium estimates, and the complexities of isotope ratio methods. Discover the historical context of the Trawsfynydd reactor, operational details, and the innovative approaches in forensic measurements. Uncover the challenges, uncertainties, and the quest for verifying nuclear material stockpiles through meticulous analysis and reconstruction efforts.
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Presentation Transcript
Forensic Measurements for Nuclear Archaeology - Trawsfynydd revisited Lukas Rademacher, Malte G ttsche
A fissile material baseline declaration Yongbyon reactor Keith Luse Hanford plutonium production DOE, Plutonium The First 50 Years 2 Forensic Measurements for Nuclear Archaeology Trawsfynydd revisited | Lukas Rademacher, Malte G ttsche | 22.07.2024
Nuclear archaeology Reconstruction of fissile material production and removal history Goal: Establish and verify existing stocks of nuclear material U.S. plutonium inventory DOE, Plutonium The First 50 Years 3 Forensic Measurements for Nuclear Archaeology Trawsfynydd revisited | Lukas Rademacher, Malte G ttsche | 22.07.2024
Nuclear archaeology Trawsfynydd Plutonium Estimate Analysis of samples taken from moderator graphite Measurement of Ti-48/Ti-49 ratio to deduce neutron fluence (Isotope Ratio Method IRM) Conversion of neutron fluence to plutonium production Good agreement between estimate and declared Trawsfynydd Plutonium Estimate Brude D. Reid et al. 4 Forensic Measurements for Nuclear Archaeology Trawsfynydd revisited | Lukas Rademacher, Malte G ttsche | 22.07.2024
Nuclear archaeology IRM - Caveats Significant uncertainty on plutonium estimate Complex production histories: civil/mil. mix, tritium production, more complex relation between fluence and PU production Verification of declarations besides/beyond PU production More details on operational history should be verified! 5 Forensic Measurements for Nuclear Archaeology Trawsfynydd revisited | Lukas Rademacher, Malte G ttsche | 22.07.2024
Nuclear archaeology A new approach 6 Forensic Measurements for Nuclear Archaeology Trawsfynydd revisited | Lukas Rademacher, Malte G ttsche | 22.07.2024
Trawsfynydd reactor Magnox reactor 870 MW (therm.) Operation: 1965 1981 ~20 MWd/kg total reactor burnup 2 6 refuelings per channel 2D infinite lattice model 7 Forensic Measurements for Nuclear Archaeology Trawsfynydd revisited | Lukas Rademacher, Malte G ttsche | 22.07.2024
Sensitivity analysis Step 1: Single depletion cycle Parameter Reactor power Cycle duration Fuel enrichment Range 85 1700 MW 400 3650 days 0.711 1.5 % Fuel temperature Cladding temperature Graphite temperature Graphite density 200 600 C 200 450 C 150 400 C 1.45 1.75 g/cm3 8 Forensic Measurements for Nuclear Archaeology Trawsfynydd revisited | Lukas Rademacher, Malte G ttsche | 22.07.2024
Sensitivity analysis 9 Forensic Measurements for Nuclear Archaeology Trawsfynydd revisited | Lukas Rademacher, Malte G ttsche | 22.07.2024
Sensitivity analysis Step 2: Complete histories Parameter Reactor power Fuel enrichment Graphite temperature Total active time Shutdown period Range 85 1700 MW 0.711 1.5 % 150 400 C 1200 25550 days 365 3650 days Total energy 102 43435 GWd 10 Forensic Measurements for Nuclear Archaeology Trawsfynydd revisited | Lukas Rademacher, Malte G ttsche | 22.07.2024
Sensitivity analysis 11 Forensic Measurements for Nuclear Archaeology Trawsfynydd revisited | Lukas Rademacher, Malte G ttsche | 22.07.2024
Sensitivity analysis Ratio H-3/Li-7 Fe-54/Fe-55 S-32/S-33 Cl-35/Cl-36 Ca-41/Ca-43 Ti-48/Ti-49 V-50/V-51 Sensitivities Shutdown period, power Shutdown period, power Total energy Total energy Total energy Total energy Total energy Ratio Cr-50/Cr-54 Ni-59/Ni-63 Sr-86/Sr-87 Te-122/Te-130 Ba-130/Ba-132 W-183/W-184 Sensitivites Total energy Total energy Total energy Total energy Total energy Total energy 12 Forensic Measurements for Nuclear Archaeology Trawsfynydd revisited | Lukas Rademacher, Malte G ttsche | 22.07.2024
Bayesian inference ? ? ? ?(?) ?(?) ? ? ? = P(A): Prior assumptions, info from documentation, P(B|A): Likelihood obtained from repeated sampling of datapoints/events 1. Sample parameter values from prior distribution 2. Calculate resulting data/isotope ratios 3. Calculate probability that prediction is compatible with measurement 4. Determine likelihood by combining sampled probabilities P(A|B): Posterior distribution, updated prior ? ????????? 2 ? ? ?????????? 2?? ? ? ? ? = exp ?=1 13 Forensic Measurements for Nuclear Archaeology Trawsfynydd revisited | Lukas Rademacher, Malte G ttsche | 22.07.2024
Gaussian Process Regression Inference requires thousands of predictions to produce meaningful results Obtaining predictions from full reactor simulations is unfeasible Surrogate model: Gaussian Process Regression Figueroa & G ttsche, Gaussian Processes for Surrogate Modeling of Discharged Fuel Nuclide Compositions 14 Forensic Measurements for Nuclear Archaeology Trawsfynydd revisited | Lukas Rademacher, Malte G ttsche | 22.07.2024
Reconstruction 15 Forensic Measurements for Nuclear Archaeology Trawsfynydd revisited | Lukas Rademacher, Malte G ttsche | 22.07.2024
Conclusion & Outlook Extension of IRM methodology Isotopic ratios with sensitivities to operational parameters available, but not numerous Reconstruction of reactor power, total active time, total energy and shutdown period Ongoing work: Different depletion cycles Detailed investigation of uncertainties Fine tuning isotope selection & reconstruction algorithm 16 Forensic Measurements for Nuclear Archaeology Trawsfynydd revisited | Lukas Rademacher, Malte G ttsche | 22.07.2024
Thank you for your attention! Questions?
