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Title: Godiva-IV Dosimetry Exercise 2022 Preliminary Results

Conference ·
OSTI ID:2205152
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  1. Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
  2. Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
  3. Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
  4. Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
  5. Savannah River Site (SRS), Aiken, SC (United States)
  6. Hanford Site (HNF), Richland, WA (United States)
  7. Oak Ridge Y-12 Plant (Y-12), Oak Ridge, TN (United States)
  8. Naval Dosimetry Center, Bethesda, MD (United States)
  9. Atomic Weapons Establishment, Reading, Berkshire (United Kingdom)
  10. Inst. de Radioprotection et de Sûrete Nucleaire (ISRN), Fontenay-aux-Roses (France)

Integral Experiment Request (IER) 538 is part of a series of dose characterization and nuclear accident dosimetry (NAD) exercises performed under the Department of Energy (DOE) Nuclear Criticality Safety Program (NCSP). This is the second NAD exercise using the Godiva-IV critical assembly and the third NAD exercise overall. The participating laboratories provided their own dosimeters that were mounted on the Lawrence Livermore National Laboratory (LLNL) BOttle Manikin ABsorption (BOMAB) phantoms and aluminum plates. The BOMABs and plates were placed at two, three, and four meters away from the center of Godiva. Alongside the NADs, there was a LLNL Passive Neutron Spectrometer (PNS), Atomic Weapons Establishment (AWE) PNS, and Y-12 Sphere present to measure the neutron dose from Godiva. Two irradiations were conducted to test the NAD performance from each laboratory and assesses their performance to the DOE-STD-1098-2017 part 515 criteria. Neutron and gamma doses were measured prior to this exercise. This work presents a model for the neutron and gamma dose respectively to serve as the reference value. A code written in C/C++/ROOT was used to fit the measured neutron and gamma dose with the new models. It was assumed that the neutron and gamma doses are proportional to the change in temperature of Godiva after a burst irradiation. Uncertainties for the reference values were calculated using error propagation of the model’s parameters. Preliminary results (within twenty-four hours) and final results were compared for each laboratory. On average of all the participating laboratories, 32% of neutron doses and 78% of gamma doses were outside the DOE standards. One laboratory did not report their dose readings and were not included in this average. There is a bias for a lower neutron dose and a higher gamma dose based on the distribution of results. In comparison with the past Godiva-IV NAD exercise, there is an improvement in neutron dose readings by 20%.

Research Organization:
Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Los Alamos National Laboratory (LANL), Los Alamos, NM (United States); Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Savannah River Site (SRS), Aiken, SC (United States); Hanford Site (HNF), Richland, WA (United States); Oak Ridge Y-12 Plant (Y-12), Oak Ridge, TN (United States); Naval Dosimetry Center, Bethesda, MD (United States); Atomic Weapons Establishment, Reading, Berkshire (United Kingdom); Inst. de Radioprotection et de Sûrete Nucleaire (ISRN), Fontenay-aux-Roses (France)
Sponsoring Organization:
USDOE National Nuclear Security Administration (NNSA), Nuclear Criticality Safety Program (NCSP)
DOE Contract Number:
89233218CNA000001
OSTI ID:
2205152
Resource Relation:
Conference: 17. International Symposium on Reactor Dosimetry, Lausanne (Switzerland), 21 May 2023; Related Information: https://isrd17wp.reactordosimetry.org/
Country of Publication:
United States
Language:
English