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SUMMARY:Fission-Fraction Uncertainties in the Calculation of the Antineutr
 ino Flux from a VVER-1000 Reactor
DTSTART;VALUE=DATE-TIME:20261027T162500Z
DTEND;VALUE=DATE-TIME:20261027T163000Z
DTSTAMP;VALUE=DATE-TIME:20261106T051349Z
UID:indico-contribution-6415@cern.ch
DESCRIPTION:Speakers: Ivan Zhutikov (MEPhI/NRC KI)\nThe uncertainty associ
 ated with reactor fission fractions is an important contribution to precis
 ion predictions of the antineutrino flux and to antineutrino-based reactor
  monitoring. We evaluate the uncertainties and correlations of the fission
  fractions of $^{235}U$\, $^{238}U$\, $^{239}Pu$\, and $^{241}Pu$ for a VV
 ER-1000 reactor and propagate them to the calculated electron-antineutrino
  flux. Burnup-dependent atomic densities and one-group microscopic fission
  cross sections are obtained with the Serpent Monte Carlo code and combine
 d with BIPR-7A full-core calculations for the 13th fuel cycle of Unit 3 of
  the Kalinin Nuclear Power Plant. A Monte Carlo procedure is used to vary 
 the nuclide atomic densities and fission cross sections within their adopt
 ed uncertainties\, providing fission-fraction distributions\, standard unc
 ertainties\, and correlation coefficients throughout a 500 effective-day f
 uel cycle. The correlations between the isotope fission fractions evolve s
 ignificantly with burnup and are explicitly included in the uncertainty pr
 opagation. The resulting relative contribution of fission-fraction uncerta
 inties to the antineutrino flux uncertainty increases from approximately 0
 .25% at the beginning of the cycle to 0.42% at the end. This contribution 
 remains below the uncertainty associated with reactor-antineutrino spectru
 m models\, but is comparable to the characteristic thermal-power uncertain
 ty and should therefore be included in precision VVER-1000 antineutrino-fl
 ux calculations.\n\nhttps://indico.particle.mephi.ru/event/626/contributio
 ns/6415/
LOCATION:Sevastopol hotel Conference Hall 1
URL:https://indico.particle.mephi.ru/event/626/contributions/6415/
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