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Title: Integration of TRISO Fuel with Open-Cell Foam for Increased Performance and Manufacturability

Abstract

Tristructural isotropic (TRISO) fuel is a key component of advanced small modular nuclear reactors due to its inherent safety at high temperatures and irradiation levels and decreased proliferation risk relative to current reactors. TRISO particles are combined with a carbonaceous matrix and formed into various fuel element geometries. For high temperature gas-cooled reactors (HTGR), a more efficient cooling method for TRISO fuel elements may increase thermal control and allow for an increase in fuel density. At the same time, reducing fission product gas buildup and resultant stress on cladding in TRISO fuel elements for gas-cooled fast reactors (GFR) operating using a deep burn fuel cycle would significantly increase fuel lifetime. For HTGRs, the potential exists to cast and sinter a slurry of TRISO particles and graphite powder into the open cells of highly porous ceramic foam that has hollow ligaments. The foam will provide structural reinforcement for the TRISO-graphite mixture and the hollow ligaments will serve as a network of cooling passages allowing for coolant flow in much closer proximity to the fuel particles compared with current fuel elements. For GFRs using a deep burn fuel cycle, the potential exists to make TRISO-like hollow-ligament foam in which the ligaments aremore » composed of the same fuel and cladding layers as current TRISO particles and the hollow ligaments areused to vent fission products. The proposed technology development represents both near-term (HTGR) and longer-term (GFR) applications for hollow-ligament foam. In this project, the initial feasibility of an innovative cooling method for HTGR and a means of venting fission products for GFR was demonstrated for different forms of TRISO fuel. Oak Ridge National Laboratory (ORNL, Oak Ridge, TN) performed computational fluid dynamics (CFD) thermal and transport modeling of hollow-ligament foam and preliminary fuel assembly design for both fuel concepts. Ultramet fabricated development specimens using surrogate fissile materials. For the HTGR application, a slurry composed of graphite powder, zirconia particles similar in size to TRISO particles, and a phenolic binder was cast into hollow-ligament silicon carbide foam, followed by high temperature pyrolysis. Surface and cross-sectional analysis was performed to characterize infiltration uniformity and distribution of the particles within the graphite. For the GFR application, niobium facesheets were deposited over the outer surfaces of niobium foam, followed by grinding to expose the hollow ligament ends. Helium flow and vacuum tests were performed to establish gas-tight bonding between constituents. The proposed technology is anticipated to be ideal for small modular reactors currently under development by X-energy (Greenbelt, MD) and others. These advanced reactors have dramatically improved performance and operational safety margins and decreased proliferation risk compared with existing nuclear power generation technologies.« less

Authors:
;
Publication Date:
Research Org.:
Ultramet (Pacoima, CA)
Sponsoring Org.:
USDOE Office of Nuclear Energy (NE), Fuel Cycle Technologies (NE-5)
Contributing Org.:
Oak Ridge National Laboratory (ORNL, Oak Ridge, TN)
OSTI Identifier:
1495225
Report Number(s):
DOE-ULTRAMET-0017881
ULTRA-TR-18-16612
DOE Contract Number:  
SC0017881
Type / Phase:
STTR (Phase I)
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS; 36 MATERIALS SCIENCE; 42 ENGINEERING; nuclear energy, TRISO fuel, high temperature gas-cooled reactor, gas-cooled fast reactor, hollow-ligament foam, cooling, venting

Citation Formats

Williams, Brian E., and Youchison, Dennis L. Integration of TRISO Fuel with Open-Cell Foam for Increased Performance and Manufacturability. United States: N. p., 2018. Web.
Williams, Brian E., & Youchison, Dennis L. Integration of TRISO Fuel with Open-Cell Foam for Increased Performance and Manufacturability. United States.
Williams, Brian E., and Youchison, Dennis L. Mon . "Integration of TRISO Fuel with Open-Cell Foam for Increased Performance and Manufacturability". United States.
@article{osti_1495225,
title = {Integration of TRISO Fuel with Open-Cell Foam for Increased Performance and Manufacturability},
author = {Williams, Brian E. and Youchison, Dennis L.},
abstractNote = {Tristructural isotropic (TRISO) fuel is a key component of advanced small modular nuclear reactors due to its inherent safety at high temperatures and irradiation levels and decreased proliferation risk relative to current reactors. TRISO particles are combined with a carbonaceous matrix and formed into various fuel element geometries. For high temperature gas-cooled reactors (HTGR), a more efficient cooling method for TRISO fuel elements may increase thermal control and allow for an increase in fuel density. At the same time, reducing fission product gas buildup and resultant stress on cladding in TRISO fuel elements for gas-cooled fast reactors (GFR) operating using a deep burn fuel cycle would significantly increase fuel lifetime. For HTGRs, the potential exists to cast and sinter a slurry of TRISO particles and graphite powder into the open cells of highly porous ceramic foam that has hollow ligaments. The foam will provide structural reinforcement for the TRISO-graphite mixture and the hollow ligaments will serve as a network of cooling passages allowing for coolant flow in much closer proximity to the fuel particles compared with current fuel elements. For GFRs using a deep burn fuel cycle, the potential exists to make TRISO-like hollow-ligament foam in which the ligaments are composed of the same fuel and cladding layers as current TRISO particles and the hollow ligaments areused to vent fission products. The proposed technology development represents both near-term (HTGR) and longer-term (GFR) applications for hollow-ligament foam. In this project, the initial feasibility of an innovative cooling method for HTGR and a means of venting fission products for GFR was demonstrated for different forms of TRISO fuel. Oak Ridge National Laboratory (ORNL, Oak Ridge, TN) performed computational fluid dynamics (CFD) thermal and transport modeling of hollow-ligament foam and preliminary fuel assembly design for both fuel concepts. Ultramet fabricated development specimens using surrogate fissile materials. For the HTGR application, a slurry composed of graphite powder, zirconia particles similar in size to TRISO particles, and a phenolic binder was cast into hollow-ligament silicon carbide foam, followed by high temperature pyrolysis. Surface and cross-sectional analysis was performed to characterize infiltration uniformity and distribution of the particles within the graphite. For the GFR application, niobium facesheets were deposited over the outer surfaces of niobium foam, followed by grinding to expose the hollow ligament ends. Helium flow and vacuum tests were performed to establish gas-tight bonding between constituents. The proposed technology is anticipated to be ideal for small modular reactors currently under development by X-energy (Greenbelt, MD) and others. These advanced reactors have dramatically improved performance and operational safety margins and decreased proliferation risk compared with existing nuclear power generation technologies.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2018},
month = {3}
}

Technical Report:
This technical report may be released as soon as February 20, 2023
Other availability
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