Transmutation of spent nuclear fuel Jaroslav Šoltés 1 Jiří Skalička 2 1 – Czech Technical University, Prague 2 – Brno University of Technology 3 – Joint Institute of Nuclear Research, Dubna Supervisor: Lukáš Závorka 3
Feb 25, 2016
Transmutation of spent nuclear fuel
Jaroslav Šoltés1
Jiří Skalička2
1 – Czech Technical University, Prague2 – Brno University of Technology3 – 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
232Th-12: 3,64*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
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