Whole core analysis of the single-fluid double-zone thorium molten salt reactor (SD-TMSR)

O. Ashraf, Andrei Rykhlevskii, G. V. Tikhomirov, Kathryn D. Huff

Research output: Contribution to journalArticlepeer-review


The SD-TMSR (2,250 MWth) is a Single-fluid Double-zone Thorium-based Molten Salt Reactor. The active core of the SD-TMSR is divided into the inner zone (486 fuel tubes) and the outer zone (522 fuel tubes) to improve the Th-U3 breeding performance. This work adopted the SERPENT-2 Monte Carlo code to analyze the whole core model of the SD-TMSR. Built-in SERPENT-2 capabilities simulated online reprocessing and refueling and calculated the multiplication factor and Breeding Ratio (BR). We found that the molten salt Temperature Coefficient of Reactivity (αT) was negative for initial and equilibrium states. This study investigated the variation of the multiplication factor, BR, and build-up of important nuclides in the core as a function of burnup. Under online reprocessing and refueling, we studied the variation of the reactivity during 60 years of reactor operation. Additionally, the neutron spectrum shift during the reactor operation was calculated. Finally, these simulations determined the appropriate 232Th and 233U feed rates for maintaining criticality and enabled analysis of the overall SD-TMSR fuel cycle performance.

Original languageEnglish (US)
Article number107115
JournalAnnals of Nuclear Energy
StatePublished - Mar 2020


  • Breeding reactor
  • Burnup
  • MSR
  • Monte carlo code
  • Online reprocessing
  • Thorium fuel cycle

ASJC Scopus subject areas

  • Nuclear Energy and Engineering


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