Neutrinos & Non-proliferation in Europe

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2 Neutrino Sciences 2005 Neutrinos & Non-proliferation in Europe Michel Cribier CEA/Saclay DSM/DAPNIA/SPP & APC December 16, 2005 Michel Cribier 2/39

3 Physics principles allowing monitoring December 16, 2005 Michel Cribier 3/39

4 Fission with two humps Pu U December 16, 2005 Michel Cribier 4/39

5 A complex physic to predict emitted ß spectrum a simple example 1 year Q β = day Q β = s Q β = U Cooling time Q β =1917 Q β =567 December 16, 2005 Michel Cribier 5/39

6 Few basic numbers 235 U 239 Pu released energy per fission maximum energy of ν ν per fission > 1.8 MeV average inter. cross section MeV MeV 9.0 MeV 7.4 MeV cm cm 2 # int 235 U # int 235 Pu = =1.60 December 16, 2005 Michel Cribier 6/39

7 A toy model of a nuclear power plant Order of magnitudes of the effects A very simplified view of the core homogeneous neutron flux <Φσ> Allow to size the difficulty of the question December 16, 2005 Michel Cribier 7/39

8 The burn-up up (n,γ) fission ß December 16, 2005 Michel Cribier 8/39

9 The 1st cycle 110 tons of 3.5% in 235 U December 16, 2005 Michel Cribier 9/39

10 A normal cycle 107 tons of 238 U 225 kg of 235 U 50 kf of Pu December 16, 2005 Michel Cribier 10/39

11 Thermal power December 16, 2005 Michel Cribier 11/39

12 Neutrino Spectrum : d only 1 reactor "Double Chooz 150 m December 16, 2005 Michel Cribier 12/39

13 Neutrino Spectrum : d only 1 reactor "Double Chooz 150 m December 16, 2005 Michel Cribier 13/39

14 Neutrino Spectrum : d only 1 reactor "Double Chooz 150 m December 16, 2005 Michel Cribier 14/39

15 A diversion 2.96 Molten salt reactors 2.94 without stop in a 12.7 m Diversion signature 3 ν 50 m Remove 20 kg of Add 28.4 kg of 239 Pu 235 U Michel Cribier April 27, AntiNu/d 6150 Power in GWatts GWatts 6100 ν detected per day ν counting in 10 days : - normal : ± diversion : ± 250 a 1 σ effect Time in days 6000 December 16, 2005 Michel Cribier 15/39

16 More sophisticated simulations Professional reactors codes MCNP, Appolo, determinist codes Evolution : Mure, Origen Emission of antineutrinos in time, in energy Coupling with detector simulation and backgrounds Study of diversion scenarios simplist : invented by physicists realist : interaction with AIEA Neutrino monitors for control masse, performances, place simplification needed what can be really controled? Is it needed? December 16, 2005 Michel Cribier 16/39

17 Computations with MURE What is MURE*? *Mure : Blackberry in french MCNP Utility for Reactor Evolution C++ code interfacing MCNP and an Evolution code. S. David, O. Laulan, O. Méplan, F. Michel-Sendis, A. Nuttin, L. Perrot, F. Perdu, J. N. Wilson December 16, 2005 Michel Cribier 17/39

18 Principle MCNP : Monte Carlo code designed for calculations of neutron flux inside a reactor. MURE runs MCNP to evaluate production of nuclei Evolution code to follow transmutation of these nuclei December 16, 2005 Michel Cribier 18/39

19 Evolution MCNP = photography of core at given time Build a «Base of links» between all potential nuclei in material Then, solve Bateman equations : dn dt i = j j λ i j N which is j λ N i i + j N j σ i j is done in time steps (Bsteps): j φ N i r i σ r i φ Δt MCNP = N B δt B December 16, 2005 Michel Cribier 19/39

20 Approximations Optimize computation time by-pass short half lived nuclei (the ones that β-decay ) Reaction rate <σφ< σφ> extrapolation between 2 MCNP runs December 16, 2005 Michel Cribier 20/39

21 Could we deduce isotopic composition from neutrino measurements? Recorded positron spectrum A different spectrum by fissile isotope December 16, 2005 Michel Cribier 21/39

22 What is the precision required? P. Huber & T. Schwetz, hep-ph ph/ , Precision spectroscopy with reactor antineutrinos 10 6 evts : 10 10m in 10d Power determ. in 3% Pu content poorly > 10% in 10d with present knowledge of flux Improve flux determ. December 16, 2005 Michel Cribier 22/39

23 Related experimental effort in France O. Bringer 1, S. Chabod 1, S. Cormon 2, M. Fallot 2, H. Faust 3, Y. Foucher 2, U. Kayser 4, A. Letourneau 1, P. Mutti 3, Y. Tall 2, K. Zbiri 2 1 CEA Saclay (SPhN) 2 Subatech (Nantes) 3 ILL Grenoble 4 Univ. Braunschweig December 16, 2005 Michel Cribier 23/39

24 Experiments at ILL D 2 O tank 2 IL - Mini-Inca chamber 180 cm α, γ,β spectroscopy H9 beam channel (98% thermal spectrum) ( n/s/cm 2 ) Lohengrin mass separator 125 cm Samples automatically - transported Irradiations <=> Measurements December 16, 2005 Michel Cribier 24/39

25 Individual ß spectrum of short life fission products Fission rate /s at target Several target : Np -> Cf thus explore fission humps The Lohengrin spectrometer at ILL selection in A/q On line selection by isobar access to FP µs Measure Q ß important for detected ν December 16, 2005 Michel Cribier 25/39

26 A fact An ambitious experimental fact (quoted by C. Bemporad) programme unknown decays contribute as much as 25% of the antineutrinos at energies > 4MeV! Integral spectra measured by precision better than 2% up p to 8 MeV Fission products contributions to neutrino spectra measured by Schreckenbach et al. measurements of Tengblad et al. disagreement with experimental integral spectra important errors : 5% at 4MeV, 11% at 5MeV and 20% at 8MeV Focus on n-rich n nuclei with yields very different in 239 Pu and 235 U fission : 86 Ge, Se, Kr, 100 Rb, Sr, Mo, Tc, Ru Irradiation tests last summer. Analysis in progress Ru 9 janvier 2004 Michel Cribier 26/10

27 90 40 Zr 50 stable Y d β Sr y β Br : Q β 10.3MeV 90 Rb : Q β 6.6MeV Yields dominated by Kr and Rb Rb min β Kr min β Kr s β β-γ Br s β β-n 0.23 December 16, 2005 Michel Cribier M. Fallot, November 19., Heidelberg 27/39

28 94 40 Zr 54 stable Y min β Br : Q β 13.3MeV? 94 Kr : Q β 7.7MeV 94 Rb : Q β 10.3MeV Yield of 94 Br = 100 to 1000 times less than isobares Sr min β Rb s β β-n Rb s β β-n Kr s β β-n Kr ms β β-n Br ms β- 0.70? β-n 0.29? December 16, 2005 Michel Cribier M. Fallot, November 19., Heidelberg 28/39

29 Integral ß spectrum ILL high flux : 1 day (H9) 20d PWR Fast measurements of decays products ß spectrum study for : U, 239 Pu - different irradiation time : burn-up - different cooling time β to install December 16, 2005 Michel Cribier 29/39 γ α

30 Within The near 200 m from cores December 16, 2005 Michel Cribier 30/39

31 What is planned? Wonderful overlap with Double Chooz oscillation (θ( 13 experiment need to improve neutrino spectrum need to improve knowledge of burn-up up no new equipment required Precise ν spectrum vs fissile element ( U, Pu) : high statistic with Double Chooz (near( near) ) : 5x10 5 ν detected per year correlation with fuel composition correlation with thermal power Good exchange with EDF needed history of the fuel rods,, position At least a valuable database Project : install a smaller detector closer from cores 13 ) December 16, 2005 Michel Cribier 31/39

32 Toward a prototype of monitor Double Chooz approach good energy measurement good signal/noise too sophisticated expensive Sands approach weak ν signature not enough rejection of background robust,, simple automatic cheap December 16, 2005 Michel Cribier 32/39

33 Interest? Closer cooperation with LLNL Combine mutual experience of detectors Test/measure at ILL : core of pure 235 U very pure ν signal vs burn-up up calibration of the ν vs thermal power simple simulation of the nuclear core A demonstrator to be shown at AIEA An already usable tool to measure the thermal power December 16, 2005 Michel Cribier 33/39

34 Conclusions Non prolif.. issues : a tough job! realistic diversion ( 50 kg Pu) is a small effect define correct conditions : detector size/positions re-measure ν spectrum emitted in fissions correlation between isotopic content and measured spectrum in Double Chooz (near( near) detector Thermal power : a less difficult job a new tool to monitor/measure measure the thermal power not so well known (> 2 %?) apparently thru temp. and flow measurement effort also needed on ν spectrum from fissions An external/independant device to monitor nuclear reactor disuasive by itself : cannot hide stops or change of power virtually impossible to fake the ν signal December 16, 2005 Michel Cribier 34/39

35 An (even( even) ) more difficult demand An interest in remote detection of kton atomic test neutrino is an unambiguous signature An extremely weak signature 1 kton atomic 100 km => 3 interactions in a 1.7 Mton detector (120m) 3 Geoneutrinos detectors paved the way for a global network of survey December 16, 2005 Michel Cribier 35/39

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