Transport code studies of INTOR at PPPL

Solar particle events (SPEs) can pose serious threats for future crewed missions to the Moon. Historically, there have been several extreme SPEs that could have been dangerous for astronauts, and thus analyzing their potential risk on humans is an important step towards space exploration. In this work, we study the effects of a well-known SPE that occurred on 23 February 1956 on a mission in cis-Lunar space. Estimates of the proton fluence spectra of the February 1956 event were obtained from three different parameterized models published within the past 12 years. The studied geometry consists of a female phantom in the center of spherical spacecraft shielded by aluminum area densities ranging from 0.4 to 40 g cm−2. The effective dose, along with lens, skin, blood forming organs, heart, and central nervous system doses, were tallied using the On Line Tool for the Assessment of Radiation In Space (OLTARIS), which utilizes the High Z and Energy TRansport code (HZETRN), a deterministic radiation transport code. Based on the parameterized models, the results herein show that thicknesses comparable to a spacesuit might not protect against severe health consequences from a February 1956 category event. They also show that a minimum aluminum shielding of around 20 g cm−2 is sufficient to keep the effective dose and critical organ doses below NASA’s permissible limits for such event. In addition, except for very thin shielding, the input models produced results that were within good agreement, where the doses obtained from the three proton fluence spectra tended to converge with slight differences as the shielding thickness increases.

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Experimental and simulation study of impurity transport response to RMPs in RF-heated H-mode plasmas at EAST

Journal of Plasma Physics ◽

10.1017/s0022377821000222 ◽

2021 ◽

Vol 87 (2) ◽

Author(s):

Germán Vogel ◽

Hongming Zhang ◽

Yongcai Shen ◽

Shuyu Dai ◽

Youwen Sun ◽

...

Keyword(s):

Inner Core ◽

Extreme Ultraviolet ◽

Transport Coefficients ◽

Three Dimensional ◽

Line Emission ◽

Core Region ◽

Emission Mitigation ◽

One Dimensional ◽

Impurity Transport ◽

Transport Code

Spatial profiles of impurity emission measurements in the extreme ultraviolet (EUV) spectroscopic range in radiofrequency (RF)-heated discharges are combined with one-dimensional and three-dimensional transport simulations to study the effects of resonant magnetic perturbations (RMPs) on core impurity accumulation at EAST. The amount of impurity line emission mitigation by RMPs appears to be correlated with the ion Z for lithium, carbon, iron and tungsten monitored, i.e. stronger suppression of accumulation for heavier ions. The targeted effect on the most detrimental high-Z impurities suggests a possible advantage using RMPs for impurity control. Profiles of transport coefficients are calculated with the STRAHL one-dimensional impurity transport code, keeping $\nu /D$ fixed and using the measured spatial profiles of $\textrm{F}{\textrm{e}^{20 + }}$ , $\textrm{F}{\textrm{e}^{21 + }}$ and $\textrm{F}{\textrm{e}^{22 + }}$ to disentangle the transport coefficients. The iron diffusion coefficient ${D_{\textrm{Fe}}}$ increases from $1.0- 2.0\;{\textrm{m}^2}\;{\textrm{s}^{ - 1}}$ to $1.5- 3.0\;{\textrm{m}^2}\;{\textrm{s}^{ - 1}}$ from the core region to the edge region $(\rho \gt 0.5)$ after the onset of RMPs. Meanwhile, an inward pinch of iron convective velocity ${\nu _{\textrm{Fe}}}$ decreases in magnitude in the inner core region and increases significantly in the outer confined region, simultaneously contributing to preserving centrally peaked $\textrm{Fe}$ profiles and exhausting the impurities. The ${D_{\textrm{Fe}}}$ and ${\nu _{\textrm{Fe}}}$ variations lead to reduced impurity contents in the plasma. The three-dimensional edge impurity transport code EMC3-EIRENE was also applied for a case of RMP-mitigated high-Z accumulation at EAST and compared to that of low-Z carbon. The exhaust of ${\textrm{C}^{6 + }}$ toward the scrape-off layer accompanying an overall suppression of heavier ${\textrm{W}^{30 + }}$ is observed when using RMPs.

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Development of high-fidelity neutron transport code STREAM

Computer Physics Communications ◽

10.1016/j.cpc.2021.107915 ◽

2021 ◽

pp. 107915

Author(s):

Sooyoung Choi ◽

Wonkyeong Kim ◽

Jiwon Choe ◽

Woonghee Lee ◽

Hanjoo Kim ◽

...

Keyword(s):

Neutron Transport ◽

High Fidelity ◽

Transport Code

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Modelling and Experimental Studies of Sorption in the Near Field of a Cementitious Repository

MRS Proceedings ◽

10.1557/proc-176-591 ◽

1989 ◽

Vol 176 ◽

Author(s):

P.L. Brown ◽

A. Haworth ◽

R. McCrohon ◽

S.M. Sharland ◽

C.J. Tweed

Keyword(s):

Near Field ◽

Experimental Studies ◽

Mass Action ◽

Chemical Equilibria ◽

Transport Code ◽

Mass Action Model ◽

Action Model ◽

Modelling Studies ◽

Simple Mass

ABSTRACTA joint experimental and modelling programme is reported, which aims to improve our understanding of sorption processes of radionuclides onto repository materials. Diffusion/sorption experiments of sorption onto cement are described, although results are limited at this stage. The modelling studies use the coupled chemical equilibria and transport code CHEQMATE to simulate some of these experiments. The chemical part of the model is based on a simple mass-action model of sorption. More detailed comparisons will continue when the experiments are terminated, and the samples are sectioned.

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