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Research Project Highlights

Analysis of a Gen-IV Liquid Salt Cooled High Temperature Reactor

Advanced High Temperature Reactor

Advanced High Temperature Reactor

  • AHTR proposed in 2003 for 3,400 MW power production at high temperature (650 – 750 °C) and low pressure (1 atm) operation with solid fuel form
  • High temperature allows for high efficiency electricity production using Brayton Cycle and thermochemical production of hydrogen
  • Low operating pressure alleviate need for thick-walled pressure vessels and passive decay heat rejection systems
  • Solid fuel form helps minimize coolant radioactivity and prevent fission product corrosion mechanisms

*image: D.E. Holcomb, D. Ilas, V.K. Varma, A.T. Cisneros, R.P. Kelly, J.C. Gehin, “Core and Refueling Design Studies for the Advanced High Temperature Reactor”, Oak Ridge National Laboratory, ORNL/TM-2011/365, September 2011

Fuel Description

  • Plank based, graphite moderated  fuel form with LiF-BeF2 (“FLiBe”) coolant and embedded TRISO fuel particles
  • FLiBe coolant, though expensive, has good heat transfer characteristics, irradiation performance, and low activation
  • Plank form provides greater design C / HM ratio  flexibility, allows for direct instrumentation, and has enhanced passive cooling capabilities
  • Fuel dispersed in two fuel stripe regions for improved heat conduction

Fuel Cell example

T-H Coupled Simulations

T-H Coupled Simulations

T-H Coupled Simulations

Employing Enhanced Accident Tolerant Claddings in LWRs

Alternate Cladding Material

  • The reactivity of the design has a dependence on the cladding material due to different thermal neutron absorption properties.
  • A reduction in overall reactivity can result in the inability to meet cycle length requirements of the reactor
  • Depletion of UO2 fuel was calculated in the 2D lattice physics models with the cladding materials
  • BWR study focused on FeCrAl and SiC as they performed better neutronically than austenitic cladding options

Full-Core BWR Simulations

  • Parametric study performed with FeCrAl bundles in full-core model
  • Enrichment and cladding thickness perturbed until matching base case cycle length
  • Full-core simulations were consistent with lattice physics results

Fuel Core Simulations