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Title: Molten uranium dioxide structure and dynamics

Journal Article · · Science
 [1];  [2];  [3];  [4];  [3];  [4];  [3];  [3];  [4];  [5];  [3]
  1. Argonne National Laboratory (ANL), Argonne, IL (United States); Stony Brook Univ., Stony Brook, NY (United States); Materials Development Inc., Arlington Heights, IL (United States)
  2. Stony Brook Univ., Stony Brook, NY (United States)
  3. Argonne National Laboratory (ANL), Argonne, IL (United States)
  4. Materials Development Inc., Arlington Heights, IL (United States)
  5. Carnegie Inst., Washington, DC (United States)

Uranium dioxide (UO2) is the major nuclear fuel component of fission power reactors. A key concern during severe accidents is the melting and leakage of radioactive UO2 as it corrodes through its zirconium cladding and steel containment. Yet, the very high temperatures (>3140 kelvin) and chemical reactivity of molten UO2 have prevented structural studies. In this work, we combine laser heating, sample levitation, and synchrotron x-rays to obtain pair distribution function measurements of hot solid and molten UO2. The hot solid shows a substantial increase in oxygen disorder around the lambda transition (2670 K) but negligible U-O coordination change. On melting, the average U-O coordination drops from 8 to 6.7 ± 0.5. Molecular dynamics models refined to this structure predict higher U-U mobility than 8-coordinated melts.

Research Organization:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Organization:
USDOE Office of Science (SC)
Grant/Contract Number:
SC00112704
OSTI ID:
1174101
Report Number(s):
BNL-107388-2015-JA; R&D Project: LS001
Journal Information:
Science, Vol. 346, Issue 6212; ISSN 0036-8075
Publisher:
AAASCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 63 works
Citation information provided by
Web of Science

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Cited By (6)

High wettability of liquid caesium iodine with solid uranium dioxide journal September 2017
Investigation of Structure and Dynamics in Disordered Materials Using Containerless Techniques with In-Situ Quantum Beam and Thermophysical Property Measurements journal February 2018
Corium lavas: structure and properties of molten UO2-ZrO2 under meltdown conditions journal February 2018
Polymorphic transition and nucleation pathway of barium dititanate (BaTi2O5) during crystallization from undercooled liquid journal May 2019
Using laser remote heating to simulate extreme thermal heat loads on nuclear fuels journal January 2020
Superionic UO 2 : A model anharmonic crystalline material journal May 2019

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