EPJ Nuclear Sciences & Technologies (Jan 2018)

Sensitivity and uncertainty analysis of βeff for MYRRHA using a Monte Carlo technique

  • Iwamoto Hiroki,
  • Stakovskiy Alexey,
  • Fiorito Luca,
  • Van den Eynde Gert

DOI
https://doi.org/10.1051/epjn/2018023
Journal volume & issue
Vol. 4
p. 42

Abstract

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This paper presents a nuclear data sensitivity and uncertainty analysis of the effective delayed neutron fraction βeff for critical and subcritical cores of the MYRRHA reactor using the continuous-energy Monte Carlo N-Particle transport code MCNP. The βeff sensitivities are calculated by the modified k-ratio method proposed by Chiba. Comparing the βeff sensitivities obtained with different scaling factors a introduced by Chiba shows that a value of a = 20 is the most suitable for the uncertainty quantification of βeff. Using the calculated βeff sensitivities and the JENDL-4.0u covariance data, the βeff uncertainties for the critical and subcritical cores are determined to be 2.2 ± 0.2% and 2.0 ± 0.2%, respectively, which are dominated by delayed neutron yield of 239Pu and 238U.