Liquid salt cooled flexible conversion ratio fast reactor: Neutronic design

Eugene Shwageraus, Pavel Hejzlar, Michael J. Driscoll

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


This paper presents the neutronic design of a liquid salt cooled fast reactor with flexible conversion ratio. The main objective of the design is to accommodate interchangeably within the same reactor core alternative transuranic actinides management strategies ranging from pure burning to self-sustainable breeding. Two, the most limiting, core design options with unity and zero conversion ratios are described. Ternary, NaCl-KCl-MgCl2 salt was chosen as a coolant after a rigorous screening process, due to a combination of favourable neutronic and heat transport properties. Large positive coolant temperature reactivity coefficient was identified as the most significant design challenge. A wide range of strategies aiming at the reduction of the coolant temperature coefficient to assure self-controllability of the core in the most limiting unprotected accidents were explored. However, none of the strategies resulted in sufficient reduction of the coolant temperature coefficient without significantly compromising the core performance characteristics such as power density or cycle length. Therefore, reactivity control devices known as lithium thermal expansion modules were employed instead. This allowed achieving all the design goals for both zero and unity conversion ratio cores. The neutronic feasibility of both designs was demonstrated through calculation of reactivity control and fuel loading requirements, fluence limits, power peaking factors, and reactivity feedback coefficients.

Original languageEnglish
Pages (from-to)2626-2645
Number of pages20
JournalNuclear Engineering and Design
Issue number12
StatePublished - 1 Dec 2009
Externally publishedYes

ASJC Scopus subject areas

  • Mechanical Engineering
  • Nuclear and High Energy Physics
  • Safety, Risk, Reliability and Quality
  • Waste Management and Disposal
  • General Materials Science
  • Nuclear Energy and Engineering


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