Neutron Production in a Massive Uranium Spallation Target

Transcription

1 Neutron Production in a Massive Uranium Spallation Target L.Zavorka+c, J.Adam, A.Baldin, W.Furman, J.Khushvaktov, Yu.Kish+u, V.Pronskikh+f, A.Solnyshkin, V.Stegailov, V.Tsoupko-Sitnikov, S.Tyutyunnikov, R.Vespalec+c, J.Vrzalova+c, M.Zeman Joint Institute for Nuclear Research, Dubna, Russia Technical University, Prague, Czech Republic u Uzhhorod National University, Uzhhorod, Ukraine f Fermi National Accelerator Laboratory, Batavia, USA c Czech V.Chilap CPTP «Atomenergomash», Moscow, Russia P.Caloun, M.Suchopar Nuclear Physics Institute, Rez, Czech Republic P.Zhivkov Institute for Nuclear Research and Nuclear Energy, Bulgaria & colleagues of the E&T-RAW collaboration QUINTA

2 «Energy and Transmutation of Radioactive Waste» J.Adam, A.Baldin, A.Berlev, W.Furman, N.Gundorin, B.Gus kov, M.Kadykov, J.Khushvaktov, Yu.Kish, Yu.Kopatch, E.Kostyuhov, I.Kudashkin, A.Makan kin, I.Mar in, A.Polansky, V.Pronskikh, A.Rogov, V.Schegolev, A.Solnyshkin, V.Tsupko-Sitnikov, S.Tyutyunnikov, A.Vishnevsky, N.Vladimirova, A.Wojciechowski, R.Vespalec, J.Vrzalova, L.Zavorka, M.Zeman Joint Institute for Nuclear Research, Dubna, Russia V.Chilap, A.Chinenov, B.Dubinkin, B.Fonarev, M.Galanin, V.Kolesnikov, S.Solodchenkova CPTP «Atomenergomash», Moscow, Russia M.Artyushenko, V.Sotnikov, V.Voronko KIPT, Kharkov, Ukraine A.Khilmanovich, B.Marcynkevich Stepanov IP, Minsk, Belarus K. Husak, S.Korneev, A.Potapenko, A.Safronova, I.Zhuk JIENR Sosny near Minsk, Belarus M.Suchopar, O.Svoboda, V.Wagner INP, Rez near Praha, Czech Republic Ch. Stoyanov, O.Yordanov, P.Zhivkov Institute of Nuclear Research and Nuclear Energy, Sofia, Bulgaria M.Shuta, E.Strugalska-Gola, S.Kilim, M.Bielevicz National Centre for Nuclear Research, Otwock-Swerk, Poland S.Kislitsin, T.Kvochkina, S. Zhdanov Institute of Nuclear Physics NNC RK, Almaty, Kazakhstan M. Manolopoulou Aristotle Uni-Thessaloniki, Thessaloniki, Greece W.Westmeier Gesellschaft for Kernspektrometrie, Germany R.S.Hashemi-Nezhad School of Physics, University of Sydney, Australia

3 Motivation 1990s E&T-RAW 2016? J.W.Weale, et al., Journal.of Nucl.Ene.,A&B 14 (1961) 91. Y. Kadi, A.H-Martinez NIM A 562 (2006) 573. S. Andriamonje, et al., Phys.Lett.B 348 (1995) 697

4 Introduction The main aim of the E&T-RAW research: Investigation of electronuclear production of neutrons for nuclear energy generation and transmutation of spent nuclear fuel in the deep subcritical Accelerator Driven Systems (ADS) Attention has been focused on core with maximally hard neutron spectrum 4

5 Hard neutron spectrum Transmutation of long-lived actinides and fission products (FP) into shortlived or stable isotopes 237 Np Cross Sections (n,g) (n,f) (n,xn) Cross section (b) (n,f) (n,g) (n,2n) Neutron energy (GeV) 5

6 Introduction A recently introduced scheme of subcritical ADS with a hard spectrum has been called Relativistic Nuclear Technology (RNT) deep subcritical natural (depleted) uranium/thorium core spent nuclear fuel elements high-temperature helium coolant minimal neutron leakage Energy of incident particles E p,d ~ 10 GeV 6

7 Crucial point in RNT: Beam energy V.Yurevich, et al. PPN (2006) ø 20 x 60 cm lead target E d (GeV) < E n > (MeV) W/E d (%) A. Krása, et al. NIM A (2010) ø 10 x 100 cm lead target compilation of experimental data + new measurement maximum neutron production around the beam energy 1 GeV Kinetic energy of neutron radiation E kin and mean neutron energy < E n > grow Energy W spent on neutron production increases as well STILL Optimal beam energy for ADS: OPEN 7

8 Neutrons at higher energies Considerable increase in average multiplicity of prompt-fission neutrons up to E n = 200 MeV Prompt-fission neutron average kinetic energy (Watt spectrum) increases as well (20% higher at E n = 200 MeV) Prompt neutron yield (ppf) U EXFOR: J.Taieb, J.Frehaut, J.Frehaut, T.Ethvignot, I.Asplund-Nilsson, Neutron energy (MeV) 8

9 Fundamental requirement: Maximum hard neutron spectrum Increase in: Neutron multiplicity due to (n,xn) Mean neutron energy f(e beam ) Average kinetic energy f(e n ) Neutron yield f(e n ) Decrease in: Neutron production per one proton above 1 GeV Neutron flux (cm -2 GeV -1 deuteron -1 AGeV -1 ) Monte Carlo simulation tools: MARS15 R 30 R 30 R 120 R 120 R = 30 mm Neutron energy (GeV) R = 120 mm Experimental investigation at the quasi-infinite target 9

10 RNT Dubna Central part of the quasi-infinite uranium target QUINTA has been studied since kg set-up of metallic natural uranium irradiated by deuteron beams of energy from 0.5 AGeV up to Experimental investigation of neutron spectrum and transmutation of actinides Beam power gain approx. 2 Calculated neutron leakage 80% 10

11 QUINTA target assembly 11

12 QUINTA Nuclotron 512 kg nat U December 2013 Deuteron beam: (Al, Cu monitors) E d = 2.12(3) particles E d = 6.08(6) particles 30 cm 12

13 Activation samples Natural uranium Enriched uranium 95.17% Enriched uranium 4.83% 235 U and 238 U 238 U 235 U 99.28% Natural uranium 0.72% Cross section (b) Cross sections U(n,f) U(n,f) U(n,g) 238 U(n,2n) JENDL-HE/2007 TENDL 2013 TALYS Neutron energy (MeV) Reactions: 235,238 U(n,f) 238 U(n,g) 239 Pu 238 U(n,2n) 237 U Followed by two b - decays 13

14 Experimental methods Activation measurement technique Gamma spectroscopy with the use of HPGe detectors Canberra and ORTEC (20%, resp. 30% relative efficiency) Calibrated with standards made in 2013; Efficiency compared with MC simulation 14

15 Isotope identification Half-life (min. 6 measurements) Energy and intensity of gamma line Reaction rates calculated from measured activity Included corrections: decay during irradiation, cooling and measurement, dead time, detector efficiency, nonlinearity, beam instability, gamma line intensity, self-absorption, gamma coincidence summing, nonpoint-like source 15

16 Results on 238 U(n,2n) 238 U(n,g) Radial production after section U(n,2n) 237 U U(n,g) 239 Pu Reaction Rate (1E-28 AGeV -1 ) 100 Reaction Rate (1E-28 AGeV -1 )

17 Results on 238 U(n,2n) 238 U(n,g) Radial production after section U(n,2n) 237 U 238 U(n,g) 239 Pu Reaction Rate (1E-28 AGeV -1 ) Reaction Rate (1E-28 AGeV -1 )

18 Results on 238 U(n,2n) 238 U(n,g) (n,2n)/(n,g) spectral indices Spectral index (n,2n)/(n,g) (-) after 2 nd section Spectral index (n,2n)/(n,g) (-) after 4 rd section

19 Results on 238 U(n,2n) 238 U(n,g) Longitudinal production U(n,2n) 237 U U(n,g) 239 Pu Reaction Rate (1E-28 AGeV -1 ) 100 Reaction Rate (1E-28 AGeV -1 ) Longitudinal distance (mm) Longitudinal distance (mm) 19

20 Fission rate in 235 U and 238 U Reaction rate Reaction rate / Yield 1E-25 1E-26 1E-27 1E E E E E E E-25 a) c) Central region Periphery Enriched uranium Central region Periphery Mass number Enriched uranium Reaction rate / Yield Reaction rate 1E-25 1E-26 1E-27 1E E E E E E E-26 b) Natural uranium Central region Periphery d) Natural uranium Mass number Central region Periphery ENDF/B-VII.1 CUMULATIVE YIELDS 87 Kr 88 Kr 91 Sr 92 Sr 95 Zr 97 Zr 99 Mo 103 Ru 105 Ru 129 Sb 131 I 133 I 135 I 140 Ba 143 Ce 147 Nd 149 Nd Mass number 1.0E Mass number 20

21 Results on 235 U(n,f) 238 U(n,f) Radial distribution after section Reaction rate (1E-26 AGeV -1 ) U Reaction rate (1E-26 AGeV -1 ) U 15 z = 254 mm 1 z = 254 mm 21

22 Results on 235 U(n,f) 238 U(n,f) Radial distribution after section Reaction rate (1E-26 AGeV -1 ) z = 516 mm 235 U Reaction rate (1E-26 AGeV -1 ) z = 516 mm 238 U 22

23 Results on 235 U(n,f) 238 U(n,f) Relative contribution of 235 U(n,f) to nat U(n,f) Relative fission of 235 U in nat U (%) U in nat U z = 254 mm Relative fission of 235 U in nat U (%) U in nat U z = 516 mm 23

24 Results on 238 U(n,2n) 238 U(n,g) Longitudinal relative contribution of 235 U(n,f) to nat U(n,f) Relative fission of 235 U in nat U (%) U in nat U Longitudinal distance (mm) 24

25 Conclusion Radial and longitudinal distribution of (n,2n) and (n,g) reaction rates in 238 U and fission rates in both 235 U and 238 U have been measured Results revealed a shift in the mean energy of neutron spectrum towards higher energies when increasing the deuteron beam energy from to Contribution of 235 U to the total fission rate in nat U was determined to be up to 10% in the peripheral region of the QUINTA target and is beam-energy-dependent

26 Future plans 500 kg 20 tons Experiments with BURAN (20t nat U) will be realized in the near future (2016) Phasotron E p = 660 MeV: Neutron spectrum measurements with a set of 235,238 U, 232 Th, Bi, Au, Y, Co, Al monoisotope activation detectors (unfolding of neutron spectra) Collaboration is welcome

27 Thank you for your attention

28 Activity (s -1 ) Experimental results on p-t-v Mean neutron energy in dependence on mass distribution of fission products Pd 112 Ag Time (days) Yield (%) MeV 100 MeV 50 MeV 1 MeV 91 Sr 112 Ag Inverse peak-to-valley (p-t-v) 97 Zr ratio for 238 U using 112 Ag, 115 Cd isotopes in valley 238 U 115 Cd 135 I 133 I 131 I 143 Ce Mass number TALYS 1.4

29 Experimental results on p-t-v 112 Ag inverse peak-to-valley ratio 112 Ag inverse peak-to-valley ratio 112 Ag inverse peak-to-valley ratio (-) E d = z = 254 mm 91 Sr 97 Zr 131 I 133 I 135 I 143 Ce 112 Ag inverse peak-to-valley ratio (-) E d = z = 254 mm 91 Sr 97 Zr 131 I 133 I 135 I 143 Ce Ag inverse peak-to-valley ratio 112 Ag inverse peak-to-valley ratio 112 Ag inverse peak-to-valley ratio (-) E d = z = 516 mm 91 Sr 97 Zr 131 I 133 I 135 I 143 Ce 112 Ag inverse peak-to-valley ratio (-) E d = z = 516 mm 91 Sr 97 Zr 131 I 133 I 135 I 143 Ce