Uranium critical point problem

Iosilevskiy, Igor; Gryaznov, V. K.

doi:10.1016/j.jnucmat.2005.04.011

Cited by 30 publications

(18 citation statements)

References 27 publications

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“…to liquid uranium in the temperature range of 1000-7000 K will help to determine the critical point, which is highly uncertain for this metal. Measurements with uranium-containing compounds like uranium dioxide can confirm or disprove predicted different chemical compositions of coexisting phases, which is referred to non-congruent evaporation [4,6,7].…”

Section: Quasi-static Heating Of Stack Targetsmentioning

confidence: 96%

“…Hence, the caloric expansion coefficient a p ¼ ðoq=oHÞ p is obtained. Since at t ¼ t x the heated sample is fairly homogeneous, a measurement of the surface temperature defines the thermal expansion coefficient a 0 p ¼ ðoq=oTÞ p and the heat capacity c p ¼ ðoH=oTÞ p [4,5]. The proposed experimental scenario applied, e.g.…”

Section: Quasi-static Heating Of Stack Targetsmentioning

confidence: 99%

“…The main goal is to detect the moment t x when the pores of the heated sample close [4,5]. This corresponds to the time when quasi-isobaric expansion of each single grain is terminated and quasi-isochoric heating of the bulk sample begins.…”

Section: Introductionmentioning

confidence: 99%

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Quasi-static heating of stack targets with intense ion beams for equation of state measurements

Tauschwitz

Efremov

Maruhn

et al. 2009

Nuclear Instruments and Methods in Physics Research Section B:

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Section: Quasi-static Heating Of Stack Targetsmentioning

confidence: 96%

Section: Quasi-static Heating Of Stack Targetsmentioning

confidence: 99%

See 1 more Smart Citation

Quasi-static heating of stack targets with intense ion beams for equation of state measurements

Tauschwitz

Efremov

Maruhn

et al. 2009

Nuclear Instruments and Methods in Physics Research Section B:

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“…Studies of the EOS of nuclear materials such as uranium oxide at temperatures up to 10 4 K have been published elsewhere [8][9][10][11]. On the other hand, the experimental data at temperatures above 10 4 K are scarce even for nonnuclear materials because such high temperatures are not attainable by static methods in common laboratories.…”

Section: Introductionmentioning

confidence: 99%

Numerical Analysis of the Hydrodynamic Behavior of Ion-beam-heated Uranium Targets for Equation-of-state Studies under Extreme Conditions

et al. 2015

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The equation of state (EOS) of fissile materials under extreme thermodynamic conditions is of great importance to assess the safety of nuclear energy systems related to extremely severe nuclear accidents and intentional nuclear terrorism. In this study, for a simple, safe, and precise measurement of these properties, we propose an experimental setup in which a small amount of fissile material sample is homogeneously heated by an intense short-pulsed heavy-ion beam, and subsequent hydrodynamic motion is examined. As an example, we investigated the response of a slab of uranium foam (density = 5% of solid density) to a pulsed 23 Na + beam with a duration of 2 ns and peak irradiation flux of 5 GW/mm 2 . The target thickness and incident beam energy were adjusted to 80 μm and 1.5 MeV/u, respectively, for the beam-energy deposition to occur almost at the top of the Bragg peak and inhomogeneity in the stopping power to be 2.5%. The hydrodynamic motion of the target during and after irradiation was calculated with a one-dimensional radiation hydrodynamic code. To calculate beam-energy deposition in the target, we used density-and temperature-dependent projectile stopping data obtained with a finite-temperature Thomas-Fermi target atomic model and degeneracy-dependent dielectric response functions. The numerical results showed that the target was almost isometrically heated up to 10 5 K well before the rarefaction wave reached the center of the target, and fairly homogeneous temperature and density distributions were obtained at the end of the pulse duration. We discuss the feasibility of experimental EOS studies, such as the evaluation of pressures at off-Hugoniot conditions as a function of internal energy from the measurements of the target expansion velocity.

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“…EOS of nuclear materials such as uranium oxide at temperatures up to 10 4 K (kT ≈ 14; 1 eV) has been studied elsewhere (Morita & Fischer, 1998;Ronchi et al, 2004;Iosilevskiy & Gryaznov, 2005;Pflieger et al, 2011). However, the data in the temperatures over ≈ 10 4 K are generally not available by static methods.…”

Section: Introductionmentioning

confidence: 99%

Numerical research on the ion-beam-driven hydrodynamic motion of fissile targets for nuclear safety studies

2014

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As a method to evaluate high-temperature equation of state (EOS) data of fissile materials precisely and safely, we numerically examined an experimental setup based on a sub-range fissile target and a high-intensity shortpulsed heavy-ion beam. As an example, we calculated one-dimensional hydrodynamic motion of a uranium target with ρ = 0.03ρ solid (ρ solid ≡ solid density = 19.05 g/cm 3 ) induced by a pulsed 23 Na + beam with a duration of 2 ns and a peak power of 5 GW/mm 2 . The projectile stopping power was calculated using a density-and temperature-dependent dielectric response function. To heat the target uniformly, we optimized the experimental condition so that the energy deposition could occur almost at the top of the Bragg peak. The energy deposition inhomogeneity could be reduced to ±5% by adjusting the incident energy and the target thickness to be 2.02 MeV/u and 180 μm, respectively. The target could be heated homogeneously up to kT =7 eV well before the arrival of the rarefaction waves at the center of the target. In principle, the EOS data can be evaluated by iteratively adjusting the data embedded in the hydro code until the measured hydrodynamic motion is reproduced by the calculation. This method is consistent with the conditions of nuclear nonproliferation, because a very small amount of fissile material is enough to perform the experiment, and no shock compression occurs in the target.

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Uranium critical point problem

Cited by 30 publications

References 27 publications

Quasi-static heating of stack targets with intense ion beams for equation of state measurements

Quasi-static heating of stack targets with intense ion beams for equation of state measurements

Numerical Analysis of the Hydrodynamic Behavior of Ion-beam-heated Uranium Targets for Equation-of-state Studies under Extreme Conditions

Numerical research on the ion-beam-driven hydrodynamic motion of fissile targets for nuclear safety studies

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