Title: Evaluation of ceria as a surrogate material for UO₂ in experiments on fuel cracking driven by resistive heating

Abstract

A variety of normal operation and accident scenarios can generate thermal stresses large enough to cause cracking in light-water reactor (LWR) fuel pellets. Cracking of fuel pellets can lead to reduced heat removal, larger centerline temperatures, and localized stress in cladding all of which impact fuel performance. Furthermore, pellet cracking also contributes to a temperature reduction in the pellet since the pellet fragments tend to move towards the heat sink (cladding), and the heat flow remains predominantly radial despite the presence of cracks. It is important to understand the temperature profile on the pellet before and after cracking to improve cracking models in fuel performance codes However, in-reactor observation and measurement of cracking is very challenging owing to the harsh environment and design of fuel rods. Recently, an experimental pellet cracking test stand was developed for separate effects testing of normal operations and accident temperature conditions, using thermal imaging to capture the pellet surface temperature for evaluation of thermal stresses and optical imaging to capture the evolution of cracking in real time. Cracking experiments were initially performed using ceria (CeO₂) as a surrogate fuel material, which is useful for developing and demonstrating the experimental approaches but is also valuable inmore » its own right for cracking model development and validation. A combination of induction and resistance heating was used for volumetric heat generation in the pellet creating a thermal gradient. The material properties of CeO₂ and UO₂ are reviewed and compared for use in model development. Simulations of the experiment were performed to evaluate the behavior of the surrogate (CeO₂) fuel in BISON. The measured temperature profiles from BISON models match reasonably well with the observed experiments for the ceria pellets before cracking. The findings from this work will help improve confidence in fracture models used for fuel pellets under similar in-reactor conditions.« less

Authors:

Patnaik, S. ^[1]; Lopes, D. A. ^[2]; Spencer, B. W. ^[3]; Besmann, T. M. ^[1]; Roberts, E. ^[1]; Knight, T. W. ^[1]

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+ Show Author Affiliations

1. Univ. of South Carolina, Columbia, SC (United States)
2. Westinghouse Electric, Västerås (Sweden)
3. Idaho National Lab. (INL), Idaho Falls, ID (United States)

Publication Date:

Mon Oct 04 00:00:00 EDT 2021

Research Org.:

Idaho National Lab. (INL), Idaho Falls, ID (United States)

Sponsoring Org.:

USDOE Office of Nuclear Energy (NE)

OSTI Identifier:

1833553

Alternate Identifier(s):

OSTI ID: 1894411

Report Number(s):

INL/JOU-20-60738-Rev000
Journal ID: ISSN 0029-5493; TRN: US2300070

Grant/Contract Number:  

AC07-05ID14517; NE0008531; NE-0008531

Resource Type:

Accepted Manuscript

Journal Name:

Nuclear Engineering and Design

Additional Journal Information:

Journal Volume: 384; Journal ID: ISSN 0029-5493

Publisher:

Elsevier

Country of Publication:

United States

Language:

English

Subject:

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS; Resistive heating; Infared imaging; Optical imaging; Fracture; Ceria