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Xu, Peng

Publications and source records attributed to Xu, Peng.

3 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

MARVEL Corrosion Test Interim Report

This study explores eutectic gallium-indium-tin (e-GaInSn) as a potential coolant for the intermediate heat exchanger for the MARVEL microreactor. E-GaInSn has an exceptionally low melting point of 10.8 °C and a high boiling point exceeding 1300 °C [4]. This wide temperature range provides designers with a significant margin to coolant boiling, even under severe accident conditions. Moreover, e-GaInSn is highly stable in both air and water demonstrating a high coefficient of thermal conductivity compared to conventional coolants like water or polymer-based solutions, along with a large heat capacity and low vapor pressure [5, 6]. While its heat transfer characteristics may not match those of some other liquid metals such as sodium, they are still quite favorable [6]. More importantly, gallium does not present issues related to chemical activity in a nuclear reactor environment. These unique and advantageous properties make e-GaInSn an attractive option for reactor applications. However, it is essential to thoroughly evaluate the compatibility of E-GaInSn with structural materials, particularly steels, for which it has a relatively high affinity. Presently, the compatibility data for these liquid metals or alloys with candidate structural materials remains limited, underscoring the need for further research to ascertain their suitability as liquid breeders or coolants [7

11 - NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2024

Runtime performance of a GAMESS quantum chemistry application offloaded to GPUs

Summary Computational chemistry is at the forefront of solving urgent societal problems, such as polymer upcycling and carbon capture. The complexity of modeling these processes at appropriate length and time scales is mainly manifested in the number and types of chemical species involved in the reactions and may require models of several thousand atoms and large basis sets to accurately capture the chemical complexity and heterogeneity in the physical and chemical processes. The quantum chemistry package General Atomic and Molecular Electronic Structure System (GAMESS) has a wide array of methods that can efficiently and accurately treat complex chemical systems. In this work, we have used the GAMESS Effective Fragment Molecule Orbital (EFMO) method for electronic structure calculation of a challenging mesoporous silica nanoparticle (MSN) model surrounded by about 4700 water molecules to investigate the strong scaling and GPU offloading on hybrid CPU‐GPU nodes. Experiments were performed on the Perlmutter platform at the National Energy Research Scientific Computing Center. Good strong scaling and load balancing have been observed on up to 88 hybrid nodes for different settings of the execution parameters for the calculation considered here. When GPUs are oversubscribed by offloading work from multiple CPU processes, using the NVIDIA multi‐process service (MPS) has consistently reduced time to solution and energy consumed. Additionally, for some configuration parameter settings, oversubscription with MPS improved performance by up to 5.8% over the case without oversubscription.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗