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[en] A theory of shocks dominated by radiation energy flux in optically mixed thin-upstream thick-downstream systems, in which the temperature immediately ahead and some short distance behind the shock front are equilibrated by radiation transport, is presented. This theory is applied to determine properties of the normal and oblique radiative shock, followed by applications to interactions when radiative and polytropic shocks are present in the same system. Comparison with experimental data is presented.

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[en] A general formulation of all track-length-type estimators is given, based directly on the random walk process. Two of the commonly used track-length-type estimators are shown to be special cases of the general form, and a set of new estimators is derived

[en] MCNP is a Monte Carlo radiation transport code that has been under development for over half a century. Over the last decade, the development team of a high-energy offshoot of MCNP, called MCNPX, has implemented several physics and algorithm improvements important for modeling galactic cosmic-ray (GCR) interactions with matter. In this presentation, we discuss the latest of these improvements, a new Cosmic-Source option, that has been implemented in MCNP6.

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[en] Since the operational commissioning of the LMJ in October 2014, with the first bundle of eight beams, several experimental campaigns have been achieved. They have proven the good performance of LMJ and demonstrated its aptitudes to achieve experiments for the Simulation Program. Six experimental configurations have been defined during the ramp-up of LMJ till the completion of the facility with 176 beams and more than 30 diagnostics. This gradual phase permit to explore some of the experimental topics of the Simulation program: hohlraum energetics, radiation transport, fundamental data, implosion hydrodynamics, hydrodynamic instabilities, and fusion studies. To complete the experimental capabilities of LMJ, a PW beam, PETAL, has been added to the LMJ’s beams. PETAL offers a combination of a very high intensity multi-petawatt beam, synchronized with the nanosecond beams of the LMJ. This combination expands the LMJ experimental field in high energy density physics (HEDP). LMJ-PETAL is open to the academic communities for 20%–30% of the operating time; the first experiments have been performed in 2017. (paper)

[en] For many real-world applications in radiation transport where simulations are compared to experimental measurements, like in nuclear criticality safety, the bias (simulated - experimental k_eff) in the calculation is an extremely important quantity used for code validation. The objective of this project is to accurately predict the bias of MCNP6 [1] criticality calculations using machine learning (ML) algorithms, with the intention of creating a tool that can complement the current nuclear criticality safety methods. In the latest release of MCNP6, the Whisper tool is available for criticality safety analysts and includes a large catalogue of experimental benchmarks, sensitivity profiles, and nuclear data covariance matrices. This data, coming from 1100+ benchmark cases, is used in this study of ML algorithms for criticality safety bias predictions.

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