Transmutation of spent nuclear fuel Jaroslav Šoltés1 Jiří Skalička2 1 – Czech Technical University, Prague 2 – Brno University of Technology 3 – Joint Institute of Nuclear Research, Dubna Supervisor: Lukáš Závorka3

Main goals of transmutation Burnup of minor actinides in spent nuclear fuel to reduce its radioactivity (Am, Cm) Converting fertile isotopes to fissile isotopes (232Th, 238U)

Accelarator driven systems High energy and intensive neutron source is needed They cannot be obtained via standard thermal or fast fission in a reactor Spallation reactions are required which can be achieved only by using an accelerator driven system (ADS)

Accelerator driven systems

Neutron reactions in the ADS core Fission of heavy nuclei (Am, Cm, U, Th, Pu) Neutron capture on Th, U and fissile isotopes creation (n,xn) on Th creating additional neutrons

QUINTA experiment

HPGe γ - spectrometer Ortec

Measurements carried out Time of irradiation: 16 h Number of measurements: 8 Measured 2 h, 3 h, 11 h, 28 h, 36 h, 50 h, 45 d and 105 d after irradiation

Samples evaluation Identification of dominant gamma peaks in spectra Energy calibration Non-linearity correction Background correction Single escape and double escape peak correction Effectivity calibration correction Isotopes identification

Identified isotopes Fission products: 85mKr, 85mSr, 85mY, 87Kr, 88Kr, 88Rb, 90mY, 91Sr, 92Sr, 92Y, 93Y, 95Nb, 95mTc, 96Nb, 97Zr, 99Mo, 103Ru, 105Ru, 105Rh, 123I, 127Cs, 127Sb, 128Sb, 131Ba, 131I, 132Cs, 132I, 132Te, 133I, 134I, 135I, 135Xe, 138Cs, 139Ba, 139Ce, 140Ba, 140La, 141Ce, 142La, 143Ce Decay products of (n,xn) reactions isotopes: 210Po, 210mBi, 213Bi, 214Pb, 219Rn, 223Ra, 224Ac, 226Ac, 226Ra, 227Ac, 230Th Activation product of 232Th: 233Pa

Detected nuclei count Nuclei count: 232Th-11: 3,52*1020 233Pa-11: 7,72*108 233Pa-12: 4,46*108

Conclusion Detected fission products indicate fast neutron fission of the target 232Th Detected isotopes of 233Pa which beta-decays into 233U show effective fissile fuel breeding possibilities ADS (n,xn) reactions are important additional source to neutron balance 232Th is therefore ideal candidate for the ADS breeding zone

Thank you for your attention soltes.jaro@gmail.com jiri.skalicka@gmail.com