Ponente
Sr.
Jorge Lerendegui Marco
(Universidad de Sevilla)
Descripción
The spent fuel of current nuclear reactors contains fissile plutonium isotopes that can be combined with 238U to make mixed oxide (MOX) fuels [1]. In this way the Pu from spent fuel is used in a new reactor cycle, contributing to the long-term sustainability of nuclear energy. The use of MOX fuels in thermal and fast reactors requires accurate capture and fission cross sections. For the particular case of 242Pu, there are sizable discrepancies among the cross section measurements available [2-5] all from the 70s, resulting in and uncertainty of 14% and 35 % below and above 2 keV, respectively. In this context, the Nuclear Energy Agency (NEA) recommends in its High Priority Request List (HRPL) [6] and its report WPEC-26 [7] that the capture cross section of 242Pu should be measured with an accuracy of at least 8-10% in the neutron energy range between 500 eV and 500 keV. This work presents the time-of-flight capture measurement on 242Pu, carried out at n_TOF-EAR1 (CERN) [8] featuring a white neutron beam with energies ranging from thermal to GeV. The 242Pu(n,γ) reaction on a sample containing 95 mg of extremely pure 242Pu was measured with an array of 4 C6D6 Total Energy Detectors [9]. This contribution focuses on the analysis and results in its resonance region. In this context, the unique energy resolution feature by the n_TOF-EAR1 facility has enabled to resolve, analyze and extract individual resonance parameters for more than 250 s- and p-wave resonances up to 4 keV, 180 of which are not present in JEFF 3.2. Moreover, the achieved systematic uncertainty in the capture cross section is around 4%, fulfilling the requirements of the NEA-HPRL. Last, the statistical properties of the resonances have been studied in terms of their average resonance parameters and compared to the predictions of theoretical models. A detailed version of this work can be found in Ref. [10].
Acknowledgments
We acknowledge the n_TOF Collaboration. This measurement has received funding from the EC FP7 Programme under the projects NEUTANDALUS (Grant No. 334315) and CHANDA (Grant No. 605203), the Spanish Ministry of Economy and Competitiveness projects FPA2013-45083-P and FPA2014-53290-C2-2-P and the V Plan Propio de Investigación Programme from the University of Sevilla.
References
[1] IAEA, Status and advances in Mox fuel technology, IAEA Technical Reports Series 415 (2003)
[2] F. Poortmans et al., Nucl. Phys A 207, 342-352 (1973)
[3] R.W. Hockenbury et al., SP 425, 584-586 (1975)
[4] K. Wisshak and F. Kaeppeler, Nucl. Sc. and Eng. 66, 363 (1978)
[5] K. Wisshak and F. Kaeppeler, Nucl. Sc. and Eng. 69, 39 (1979)
[6] NEA High Request Priority List http://www.nea.fr/dbdata/hprl
[7] M. Salvatores and R. Jacqmin, Uncertainty and target accuracy assessment for innovative system using recent covariance data evaluations, ISBN 978-92-64-99053-1, NEA/WPEC-26 (2008)
[8] C. Guerrero et al., Eur. Phys. J. A 49, 27 (2013)
[9] R.Plag et al., Nucl. Instrum. and Meth. A 496, 425436 (2003)
[10] J. Lerendegui, C. Guerrero et al., Phys. Rev. C (2017) (submitted)
Autor primario
Sr.
Jorge Lerendegui Marco
(Universidad de Sevilla)
Coautor
Dr.
Carlos Guerrero
(Universidad de Sevilla)
