DP (2002–2022)

Summary

This document celebrates the 20th anniversary of the bilateral agreement between France’s CEA/DAM and the United States’ DOE/NNSA on fundamental science supporting stockpile stewardship. It highlights two decades of collaborative research spanning nuclear data, fission dynamics, material properties under dynamic compression, laser shock physics, opacities, and machine learning methods.

Cover & Imprint (Pages 1–2)

2002–2022 | 20 years of the CEA/DAM NNSA/DP Agreement / 20 ans de l’accord CEA/DAM NNSA/DP. Partners: CEA, NNSA (National Nuclear Security Administration), Lawrence Livermore National Laboratory, Los Alamos National Laboratory, Sandia National Laboratories. Report Number: LLNL-TR-843073. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. Los Alamos National Laboratory is operated by Triad National Security, LLC for the National Nuclear Security Administration of the U.S. Department of Energy (Contract No. 89233218NCA000001). Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.

Introduction / History of the Agreement (Page 3)

Introduction & History of the Agreement (M. Kreisler, NNSA & O. Vacus, CEA/DAM): For the past twenty years, there has been a very active, productive International Agreement between France and the United States of America for Cooperation on Fundamental Science supporting Stockpile Stewardship. Under this Agreement the scientists at the nuclear weapons laboratories in both countries have collaborated on many unclassified research projects in areas such as Materials in Extreme Conditions, Nuclear Physics, and Atomic and Plasma Physics. The results have enhanced the physics base of computer codes essential to the mission of ensuring nuclear stockpiles are safe, secure, and effective.

History: In 1998, Jacques Bouchard (Director of CEA/DAM) sent Daniel Gogny to LLNL to explore collaborative efforts. In January 2000, Director Bouchard wrote to Bruce Tarter (LLNL) and John Browne (LANL) suggesting formal collaboration. In March 2000, BG Thomas Gioconda (Acting Deputy Administrator for Defense Programs, US DOE) affirmed interest in establishing an unclassified basic science agreement. A seminal meeting took place at Bruyères-le-Châtel in October 2000. Formal signing occurred on March 13, 2002 by Alain Delpuech (CEA/DAM) and John Gordon (DOE/NNSA). The Agreement is managed by a Steering Committee with Co-Chairs Olivier Vacus (CEA/DAM) and Njema Frazier (NNSA), MPOCs David Riz (CEA/DAM) and Michael Kreisler (NNSA), and Technical Coordinators Thomas Mattsson (SNL), Jason Harke (LLNL), James Colgan (LANL), and Cyrille De Saint Jean (CEA/DAM). Over 125 collaboration proposals have occurred, with 20–30 active projects at any given time.

Table of Contents (Page 4)

Table of Contents:

Fission cross section measurements for high specific activity actinides (pp. 02-03)
Prompt neutron and photon emission measurements in fission (pp. 04-05)
Integral cross section measurement of the 235U(n,n’)235mU reaction in a pulsed reactor (pp. 06-07)
Collaborative exchanges of nuclear reaction algorithms and data (pp. 08-09)
Uncertainties and covariances in nuclear data, Application to plutonium (pp. 10-11)
Experimental study of the reaction zone of explosives (pp. 12-13)
Radiative neutron capture cross sections on the Lu isotopes: 176,175,174,173Lu (pp. 14-15)
Electromagnetic cascade in Monte Carlo codes and radiography (pp. 16-17)
Stellar interior opacities (pp. 18-19)
Validating the surrogate technique for (n,γ) (pp. 20-21)
Thermodynamic study of actinide alloys (pp. 22-23)
Orbital free simulation of hot dense matter (pp. 24-25)
Effects of whistler waves in the near-Earth environment (pp. 26-27)
Simulating nuclear fission dynamics (pp. 28-29)
Measurement of short-lived isomers in the radiative capture and fission reactions (pp. 30-31)
Additive manufacturing for basic shock wave physics (pp. 32-33)
Laser shock compression of hydrogen and helium to deep planetary conditions (pp. 34-35)
Microscopic theory for inelastic scattering reactions (pp. 36-37)
Studies of electron beam propagation in gas-filled cells (pp. 38-39)
Kinetics of phase transformations in metals under dynamic compression (pp. 40-41)
Fission product yield measurements (pp. 42-43)
Time dependent study of materials under dynamic compression in a diamond anvil cell (pp. 44-45)
The use of deep learning in a simulation program (pp. 46-47)
Pressure measurements in high explosives (pp. 48-49)
Methodologies for accurate determination of the refractive index of materials in the x-ray spectral range (pp. 50-51)
Glossary (pp. 52-53)
References (pp. 54-59)
Acknowledgements (p. 60)

Fission Cross Section Measurements for High Specific Activity Actinides (Page 5)

Authors: A. Chatillon, B. Mauss, P. Morfouace, J. Taïeb (CEA-DAM Île de France, Université Paris-Saclay), M. Devlin, K. J. Kelly (Los Alamos National Laboratory). Summary: Investigates 238Pu fission cross section relative to 235U from 0.7 MeV threshold up to 25 MeV. Due to high alpha activity of 238Pu (T1/2 = 87.7 y), new multibody fission chambers with excellent alpha/fission discrimination have been developed at WNR/LANSCE. Initial qualification experiments study 242Pu and 240Pu before final measurements on 238Pu.

Prompt Neutron and Photon Emission Measurements in Fission (Page 6)

Authors: A. Chatillon, B. Mauss, P. Morfouace, J. Taïeb (CEA-DAM), M. Devlin, K. J. Kelly, R. Haight (LANL). Summary: Measurement of prompt fission neutron spectra (PFNS) for 239Pu and 235U using Chi-Nu at LANSCE, PPAC detectors, and DAM’s new VENDETA array of 72 neutron detectors deployed for 238U experiments.

Integral Cross Section Measurement of the 235U(n,n’)235mU Reaction in a Pulsed Reactor (Page 7)

Authors: G. Bélier, V. Méot, P. Romain, N. Authier, D. Hyneck, X. Jacquet, Y. Jansen, J. Legendre (CEA-DAM: Île de France, Valduc), E. M. Bond, D. J. Vieira (LANL), J. A. Becker, R. Macri (LLNL). Summary: Measures integral inelastic cross section feeding the 26-minute isomer 235mU using the CALIBAN critical pulsed reactor at Valduc. The obtained integral cross section is 1.00 ± 0.13 barns, consistent with TALYS-1.4 evaluation (0.97 barns).

Collaborative Exchanges of Nuclear Reaction Algorithms and Data (Page 8)

Authors: M. Dupuis (CEA-DAM), T. Kawano (LANL). Summary: Refinement of nuclear reaction models (pre-equilibrium and compound nucleus decay, spin/parity distributions) and comparison against 238U(n,n’γ) and tungsten isotopes (182,184,186W) experimental data.

Uncertainties and Covariances in Nuclear Data, Application to Plutonium (Page 9)

Authors: C. De Saint Jean, D. Regnier, S. Hilaire, E. Bauge (CEA-DAM), T. Kawano, D. Neudecker, A. Lovell, P. Talou (LANL). Summary: Implementation of Bayesian inference methods to estimate uncertainties and covariances for fission yields, prompt neutron multiplicities, spectra, and cross sections, notably for 239Pu and 252Cf.

Experimental Study of the Reaction Zone of Explosives (Page 10)

Authors: E. Bouton, A. Sollier, Ph. Hébert, A. LeFrancois (CEA-DAM: Le Ripault, Île-de-France, Gramat), D. Dattelbaum, S. Sheffield, R. Gustavsen (LANL). Summary: Measurement of the Chemical Reaction Zone (CRZ) and von Neumann spike in TATB (PBX 9502, T2) and TNT explosives using VISAR, PDV/HetV, impedance-matched Kel-F 800 windows, and optical shadowgraphy.

Radiative Neutron Capture Cross Sections on the Lu Isotopes: 176,175,174,173Lu (Page 11)

Authors: O. Roig, A. Ebran, D. Denis-Petit, S. Hilaire, V. Méot, B. Morillon, S. Peru-Desenfants, P. Romain, C. Theroine (CEA-DAM), G. Rusev, E. M. Bond, T. A. Bredeweg, A. J. Couture, R. C. Haight, M. Jandel, T. Kawano, F. M. Nortier, J. M. O’Donnell, R. S. Rundberg, W. A. Taylor, J. L. Ullmann, D. J. Vieira (LANL). Summary: Precision measurements of radiative neutron capture cross sections across Lu isotopes using DANCE at LANSCE and targets produced via mass separation (SIDONIE) and proton irradiation (IPF at LANL), validating QRPA photon strength function formalisms.

Electromagnetic Cascade in Monte Carlo Codes and Radiography (Page 12)

Authors: S. Lemaire, M. Caillaud (CEA-DAM), G. H. Hughes, J. E. Sweezy (LANL). Summary: Cross-code comparison and benchmarking between 3D Monte Carlo electron-photon transport codes MCNP (LANL) and DIANE (CEA/DAM) for flash X-ray radiography diagnostics, improving angular deflection and knock-on electron modeling.

Stellar Interior Opacities (Page 13)

Authors: Ch. Blancard, Ph. Cossé, G. Faussurier, F. Gilleron, J.-Ch. Pain (CEA-DAM), J. E. Bailey, T. Nagayama, G. P. Loisel, G. A. Rochau, S. B. Hansen, G. S. Dunham, R. More, T. A. Gomez (SNL), C. A. Iglesias, D. A. Liedahl, B. Wilson (LLNL), J. Colgan, C. Fontes, D. Kilcrease, M. Sherrill (LANL), R. C. Mancini (Univ. Nevada - Reno), J. J. MacFarlane, I. E. Golovkin (Prism Computational Sciences). Summary: Experiments on Sandia’s Z machine at extreme temperatures (>2 MK) investigating the solar opacity discrepancy for iron (Fe), chromium (Cr), nickel (Ni), and oxygen, utilizing ultra-fast time-resolved X-ray spectroscopy.

Validating the Surrogate Technique for (n,γ) (Page 14)

Authors: O. Roig, V. Meot, A. Ebran, A. Blanc, C. Theroine, P. Chau, P. Romain (CEA-DAM), J. T. Harke, J. Escher, R. O. Hughes, N. Scielzo, I. Thompson (LLNL), M. Jandel, T. Bredeweg, E. Bond, R. Rundberg, D. Viera, J. Wilhelmy, F. Nortier, W. Taylor, J. Ullmann, A. Couture, J. O’Donnell, R. Haight, J. Wouters (LANL). Summary: Validation of surrogate reaction techniques for (n,γ) reactions in deformed nuclei (specifically 175Lu and 173Lu) using transfer reactions (3He,p), (3He,α), and (p,d) at the Orsay Tandem and TAMU Cyclotron.

Thermodynamic Study of Actinide Alloys (Page 15)

Authors: B. Oudot, C. Ciszak (CEA-DAM Valduc), A. Perron, E. E. Moore, P. E. A. Turchi (LLNL). Summary: Development of self-consistent CALPHAD thermodynamic databases informed by ab initio electronic structure calculations for multi-component plutonium alloys: Pu-(U)-Ga, Pu-(U-Am-Al)-Ga, and Pu-(U-Fe)-Ga systems.

Orbital Free Simulation of Hot Dense Matter (Page 16)

Authors: J. Clérouin, P. Arnault (CEA-DAM), L. Collins, C. Ticknor, J. Kress, A. White (LANL). Summary: Application of the Orbital-Free Molecular Dynamics (OFMD) code to model matter at extreme densities and temperatures (millions of Kelvin), examining transport properties, viscosity, and diffusion in asymmetric mixtures such as hydrogen-silver.

Effects of Whistler Waves in the Near-Earth Environment (Page 17)

Authors: J.-F. Ripoll (CEA-DAM), G. S. Cunningham (LANL). Summary: Modeling and satellite observation (NASA Van Allen Probes RBSP, ESA PROBA-V) of whistler-mode wave interactions with relativistic electrons in Earth’s radiation belts, including natural lightning superbolts and ground VLF transmitters (NWC Australia).

Simulating Nuclear Fission Dynamics (Page 18)

Authors: D. Regnier, N. Dubray (CEA-DAM), N. Schunck, M. Verriere, P. Marevic (LLNL). Summary: Development and application of time-dependent generator coordinate method (TDGCM) solver FELIX to microscopically simulate nuclear fission dynamics, scission, fragment mass/charge distributions, and angular momentum in 240Pu and fermium isotopes.

Measurement of Short-Lived Isomers in Radiative Capture and Fission Reactions (Page 19)

Authors: O. Roig, D. Denis-Petit, A. Ebran, A. Francheteau, L. Gaudefroy, V. Méot, B. Morillon, P. Romain (CEA-DAM), G. Rusev, E. M. Bond, T. A. Bredeweg, A. J. Couture, M. Jandel, T. Kawano, S. Mosby, J. M. O’Donnell, P. Talou, J. L. Ullmann (LANL). Summary: Measurement of isomeric ratios, delayed gamma cascades, and lifetimes for 177Lu, 236U, and spontaneous fission of 252Cf using DANCE and NEUANCE at LANSCE and 4π NaI arrays at CEA/DIF.

Additive Manufacturing for Basic Shock Wave Physics (Page 20)

Authors: S. Chupin, D. Rochais, Ph. Belleville, Y. Scaringella-Guerritat, L. Soulard (CEA-DAM: Le Ripault, Île de France), D. Dattelbaum, K.-S. Lee, M. Lewis (LANL), M. Kumar, J. Lind (LLNL). Summary: Direct ink write (DIW) 3D printing of cellular polymer composites (Al2O3/PDMS, graphite/PDMS, TiO2/PDMS) and ceramics, combined with ABAQUS modeling and dynamic plate-impact shock experiments diagnosed with X-ray phase-contrast imaging at the Advanced Photon Source.

Laser Shock Compression of Hydrogen and Helium to Deep Planetary Conditions (Page 21)

Authors: S. Brygoo, P. Loubeyre, F. Occelli (CEA-DAM), P. M. Celliers, J. H. Eggert, D. Fratanduono, M. Millot, Y.-J. Kim (LLNL). Summary: Dynamic laser shock compression of pre-compressed diamond anvil cell (DAC) targets and cryogenic H2/D2/He mixtures at NIF, reaching >800 GPa to study insulator-to-metal transitions, planetary interior equations of state, and phase separation in giant planets.

Microscopic Theory for Inelastic Scattering Reactions (Page 22)

Authors: M. Dupuis, S. Péru (CEA-DAM), J. E. Escher, W. Younes, E. Chimanski (LLNL). Summary: Combining deformed QRPA with Gogny interactions and reaction theory (DWBA/coupled-channels) to calculate inelastic nucleon scattering, transition densities, and rearrangement corrections in Zr, Mo, and actinides.

Studies of Electron Beam Propagation in Gas-Filled Cells (Page 23)

Authors: J. Gardelle, D. Hebert, N. Szalek, P. Grua, X. Davoine, L. Gremillet (CEA-DAM: Cesta, Île-de-France), C. H. Moore, B. M. Medina, K. L. Cartwright, I. Owens, E. L. Rhoades (SNL). Summary: Investigation of pulsed relativistic electron beam (10–100 ns, >100 keV, >1 kA) transport in low-pressure gas (0.1–10 mbar) using facilities (CESAR, RKA at CESTA; SPHINX, SATURN, HERMES at SNL) and hybrid PIC/fluid codes (EMPIRE, GAZEL, CALDER).

Kinetics of Phase Transformations in Metals Under Dynamic Compression (Page 24)

Authors: C. Chauvin, D. Palma de Barros, C. Voltz (CEA-DAM: Valduc, Gramat), J.-P. Davis, J. L. Brown, T. Ao, M. D. Knudson, D. H. Dolan (SNL). Summary: Magnetic ramp compression (ICE) of tin (Sn) across the β-γ phase transition (9.4 GPa) on pulsed-power machines (Thor at SNL; GEPI, ICE16 at CEA Gramat), combined with dynamic X-ray diffraction (DXRD) and pyrometry.

Fission Product Yield Measurements (Page 25)

Authors: P. Morfouace, G. Belier, J. Taïeb, A. Chatillon, B. Mauss (CEA-DAM), T. A. Bredeweg, M. E. Gooden, P. Talou, T. Kawano, A. Lovell (LANL), A. Tonchev, J. Silano, A. Ramirez, R. Malone, N. Schunck, M. Verrière (LLNL). Summary: High-precision measurements of energy-dependent fission product yields for 235U, 238U, and 239Pu using CALIBAN, ORPHEE, TUNL/HIGS photofission, NCERC Flattop-HEU critical assembly, and inverse kinematics with VAMOS at GANIL.

Time Dependent Study of Materials Under Dynamic Compression in a Diamond Anvil Cell (Page 26)

Authors: C. Pépin, F. Occelli, R. André, P. Loubeyre (CEA-DAM), Z. Jenei, E. F. O’Bannon, D. T. Sneed, W. J. Evans (LLNL). Summary: Development of the piezo-driven dynamic Diamond Anvil Cell (dDAC) achieving compression rates up to tens of GPa/ms and microsecond-resolved X-ray diffraction at European XFEL (studying Bi-III to Bi-V phase transitions) and resistive high-temperature heating.

The Use of Deep Learning in a Simulation Program (Page 27)

Authors: G. Kluth, G. Salin (CEA-DAM), B. K. Spears, B. Garcia, K. D. Humbird, J. Koning, K. Lewis (LLNL). Summary: Implementation of deep neural network surrogate models to replace costly NLTE atomic physics/spectral opacity calculations in Inertial Confinement Fusion (ICF) multi-physics simulation codes for NIF and LMJ, demonstrating 7x speedup.

Pressure Measurements in High Explosives (Page 28)

Authors: A. Lefrancois, V. Chuzeville, Y. Barbarin, M. Genetier, D. Picart (CEA-DAM: Gramat, Le Ripault), J. Jordan, D. Dattelbaum, R. Huber, J. Lang, D. Tasker (LANL). Summary: Project P208 focusing on piezoresistive and electromagnetic stress gauge diagnostics in high explosives (HE), addressing calibration, circuitry, bandwidth, and viscoelastic modeling in PMMA and HMX-based formulations.

Methodologies for Accurate Determination of the Refractive Index of Materials in the X-Ray Spectral Range (Page 29)

Authors: A. Rousseau (CEA-DAM Île-de-France), Y. Ménesguen, M.-C. Lépy (CEA-Saclay, LNHB), F. Delmotte, E. Papagiannouli (Université Paris-Saclay, LCF), R. Soufli, C. Burcklen, M.-A. Descalle (LLNL). Summary: Development of transmission and reflection measurement methodologies (15 eV – 100 keV) at the Advanced Light Source (ALS beamline 6.3.2) and LNHB to derive accurate mass attenuation coefficients, optical constants (δ, β), and Kramers-Kronig transformations near absorption edges.

Glossary & Acknowledgements (Pages 30–34)

Glossary of Partner Agencies & Large Facilities: Agencies: CALTECH, CEA, CENBG, DAM, DIF, DOE, EC-JRC-IRMM, ESRF, FUSTIPEN, Gramat, LANL, LETI, LLNL, Le Ripault, NNSA, ORNL, Rensselaer Polytechnic Institute, SNL, 3 Degrees of Separation (3DS), Valduc. Facilities: CALIBAN, DANCE, FIGARO, GANIL, GEANIE, GODIVA IV, HFIR, LANSCE, LSDS, LTD 1 MV, MLNSC, Moronvilliers/PEM, Accélérateur tandem Orsay, SIDONIE, STARS-LIBERACE, URSA Minor LTD, WNR.

Steering Committee: Laurence Bonnet (CEA), Catherine Cherfils (CEA), Njema Frazier (NNSA), Mike Kreisler (NNSA), Olivier Vacus (CEA).

Laboratory Technical Coordinators: James Colgan (LANL), Paul Dotson (LANL), Jason T. Harke (LLNL), Thomas Mattsson (SNL), David Riz (CEA), Cyrille de Saint Jean (CEA).

Editors: Jason T. Harke (LLNL), David Riz (CEA). Graphic Designer: A. Diaz (lead, LLNL). Web Designers: J. Barrett, D. Fenstermacher, K. Paschal, G. Pinkela, M. Regynski, A. Simpson, P. Williams, C. Willis-Chun (LLNL).