1. March 19. 2009 AAP09 - Brazil - M. Fallot et al. Collaborations Double Chooz, Nucifer and MURE Time evolution of reactor antineutrino energy spectrum and flux

2. March 19. 2009 AAP09 - Brazil - M. Fallot et al. Outline 2 reasons why antineutrino spectrum and flux vary with time : - Non equilibrium : U and Pu istope  and  energy spectrum simulations - Variation of the fuel isotopic content of a reactor core : reactor antineutrino spectrum and flux simulation proliferation scenario (taking into account out of equilibrium effects when rapid power changes)

3. March 19. 2009 AAP09 - Brazil - M. Fallot et al.  Integral  - spectra measurements: [ A. Hahn et al., Phys. Lett. B, 218, (1989)] 235 U, 239, 241 Pu targets @ILL, at better than 2% until 8 MeV  Summing individual  -spectra : [ Tengblad et al. (NPA503(1989)136) 111 nuclei @OSIRIS Studsvik and ISOLDE ]  Conversion  -  e : global shape uncertainty from 1.3%@3MeV to 9%@8MeV  Measurement only related to thermal fission  Irradiation time dependence (20 min & 1.5 d)  Don’t agree with the experimental integral spectra (important errors : 5% at 4MeV, 11% at 5MeV and 20% at 8MeV) -spectra determinations  Remaining short-lived, high Q , unknown nuclei

4. March 19. 2009 AAP09 - Brazil - M. Fallot et al.  In agreement with Chooz and Bugey data (1.9% on the e flux ) -  i (t) : relative contributions to the total fission (  i =1) -  i (E) : -spectra 235 U, 239 Pu, 241 Pu, and 238 U (Schreckenbach et al. and P. Vogel  Don’t take into account  - decay from products of radiative capture of neutron Determination of the -spectra :  Theoretical approach : Microscopic cal. of trans. mat. elts [ H-V. Klapdor, Phys. Rev. Lett., 48, (1982)] Phenomenological model for unknown nuclei + databases [ P. Vogel et al., Phys. Rev. C, 24, (1981)] Determination of the reactor -spectra :  V. Kopeikin : Resolution of the Bateman equations for selected set of fission products + fission rates from the power plants + neutron capture contributions (ENDF database)  Antineutrino experiment approaches: -spectra determinations

5. March 19. 2009 AAP09 - Brazil - M. Fallot et al. Neutron capture, non equilibrium effects « In the antineutrino energy range 1.8-3.5 MeV, the relative contribution of the additional radiation during the reactor operating period (Figs. 1, 5) is about 4%, which is somewhat greater than the error of the ILL spectra [5]. » Ratio of the reactor -spectrum obtained by conversion + calculation methods  to the - spectrum obtained by conversion method only  convers. : 1 – the additional contribution from fission product residual - activity of the previous two reactor cycles; 2 – from neutron capture by fission products; 3 – from increase of fission product - activity of the current reactor cycle from 1 day to 0.5 year; 4 – the sum (4=1+2+3) V. Kopeikin et al., arXiv:hep-ph/0110290

6. March 19. 2009 AAP09 - Brazil - M. Fallot et al. Addition to the  spectrum : 1, 2 and 3 correspond to the beginning, middle and end of the reactor operating cycle Modification of the  - and  spectra associated with neutron capture by fission products Neutron capture, non equilibrium effects But also the evolution of the  and spectra during operating (ON) and shutdown (OFF) periods Solid line is the ratio of the spent fuel pool  - spectrum to the reactor  spectrum. Dashed lines are the ratios of the reactor  - spectrum after the reactor is shut down to the reactor  - spectrum at the end of the operating cycle.  (E,t off ) /  (E,t on = 1 yr) Spent Fuel Pool 0 0.02 0.04 2 3 2.53.5 t off = 1yr t off = 1 d V. Kopeikin et al., arXiv:hep-ph/0110290

7. March 19. 2009 AAP09 - Brazil - M. Fallot et al. Developed simulation tools And results on U and Pu isotopes spectra

8. March 19. 2009 AAP09 - Brazil - M. Fallot et al. Principle of our strategy weighted  Monte-Carlo Simulation : Evolution Code MURE  - branch database : BESTIOLE, … Total e and  - energy spectra with complete error treatment  - decay rates    / e spectra Two distinct studies fissile mat. + FY neutron flux Core geometry nuclear database exp. spectrum models   -  e conversion : pas branch by branch method : no additional error  Neutron capture taken into account  Long lived fission products accumulation  Error treatment and propagation  Nuclear database tests

9. March 19. 2009 AAP09 - Brazil - M. Fallot et al. The e spectra formulation Coulomb corrections Phase space Spectral Shape factor (Well controlled for allowed and forbidden unique transitions) with depends on the  transition : Branching Ratios, End-Points,spin, parity of the mother and daughter nuclei branching ratios  individual spectra S, n (Z,A, E ) =  b n,i (E 0 ). i i P(E 0, E ) i - --  Remaining short-lived, high Q , unknown nuclei

10. March 19. 2009 AAP09 - Brazil - M. Fallot et al. Bestiole Database (ROOT and ASCII formats) Collect all available information : Nuclear Database : ENSDF Experimental spectra  111 nuclei @ISOLDE [O. Tengblad et al., Nucl. Phys. A, 503, (1989)] 950 nuclei : ~ 10000  branches ~ 500  -n branches Tag all relevant information : Forbiddenness (spin & parity) Level of approximation CEA/Saclay/SphN : D. Lhuillier, Th. Müller et al.

11. March 19. 2009 AAP09 - Brazil - M. Fallot et al. MURE * *MCNP Utility for Reactor Evolution, O. Méplan et al. ENC Proceedings (2005) Developed by CNRS/IN2P3/IPNO and LPSC Geometry Evolution Open source code : adapted to antineutrino needs (simple geometry implementation, easy coupling to databases …) Benchmarked with APOLLO2 code Fuel Burnup Fission product distributions Refined effects : out of equilibrium spectra Neutron capture on FPs …  proliferation scenario calculations Possibility to simulate : Simple cases : pure U or Pu isotope fissions and associated  spectra Complexe cases : reactor and associated  spectra

12. March 19. 2009 AAP09 - Brazil - M. Fallot et al. Obtained spectra X  4% agreement in the range 2 -6 MeV with Schreckenbach’s data, higher discrepancy at high energy X simulation errors (cf. Th. Müller’s talk) within the experimental error bars Données :[ A. Hahn et al., Phys. Lett. B, 218, (1989)] Rudstam data + Bestiole + JENDL + Qb Rudstam data + Bestiole Ratio : (MURE - DATA)/DATA

13. March 19. 2009 AAP09 - Brazil - M. Fallot et al. Several tracks to solve these problems : - Use of Gross Theory in existing databases such as JENDL3.3 when the considered nuclei have been treated, other models… (QRPA) - Inclusion of existing TAGS nuclear data and new measurements - Sensitivity to fission yields databases Origins of the discrepancy and solutions  - ? ZANZAN Z+1 A N-1 γ γ γ2 γ1 Pandemonium effect : use of Ge detectors to measure the decay schemes : underestimate of b branches towards high energy excited states : overestimate of the high energy part of the FP b spectra Unknown fission products contribute importantly at E>5-6MeV - an alternative : the « ratio method » (see Th. Müller’s talk) : relying on the very precise Schreckenbach’s team 235U and 239Pu b spectra measurements + corrections to be applied for time evolution and neutron capture

14. March 19. 2009 AAP09 - Brazil - M. Fallot et al.  decay database testing and fission yields Treatment of Pandemonium with JENDL3.3 : Gross Theory spectra Rudstam et al. data JENDL total JENDL exp. (ENSDF) BESTIOLE exp. (ENSDF) BESTIOLE beta-n branches (ENSDF) 142 Cs 83 As 85 As 89 Br Different databases for fission yields : important input for MURE simultion : Yields from JENDL3.3 Yields from ENDFB Yields from JEFF31 With beta spectra from : BESTIOLE + JENDL Gross Theory + Q  approx. Ratio : (MURE - DATA)/DATA 235 U [K. Takahashi and M. Yamada 1969] -> comparer JENDL avec JEFF3 et ENDFBVII M. Fallot et al. ND2007, L. Giot et al. Physor 2008

15. March 19. 2009 AAP09 - Brazil - M. Fallot et al. Evolution of the spectrum shape with time 235 U under monoenergetic n flux (no moderation) : evolution during 1 year To be studied in the reactor framework : under realistic n spectrum Bin per bin comparison with respect to 0.7day -spectrum for 60 time steps during 1 year 0 2 4 6 8 10 12 Energy (MeV)

16. March 19. 2009 AAP09 - Brazil - M. Fallot et al. World-wide initiatives 238 U  - spectrum integral measurement in Münschen (Niels Haag et al. @Garching ) : March-April 2009 (now !!!) 235 U/ 239 Pu ratio measurement in Moscow @Kurchatov institute (V. Kopeikin et al.) Measurements of Pandemonium nuclei : Total Absorption Spectrometry collab. (Valence group) D. Jordan, PhD Thesis TAS measurements @ Univ. Jyvaskyla Using large 4  scintillation detectors, aims to detect the full  -ray cascade rather than individual  -rays 12 BaF 2 Crystals New Surrey-Valencia Total Absorption Spectrometer

17. March 19. 2009 AAP09 - Brazil - M. Fallot et al. Antineutrino energy spectrum and flux reactor simulations, « gross » proliferation scenarios

18. March 19. 2009 AAP09 - Brazil - M. Fallot et al. Scenarios and reactors of interest for IAEA ?  PWRs  BWR, FBR, CANDU reactors  Research reactor/isotope production reactors Pth >10MWth  Future reactors (PBMRs, Gen IV reactors, ADS, especially reactors using carbide, nitride, metal or molten salt fuels.  PWRs : PWR (full core) simulation and simple refuelling scenario studies  BWR, FBR, CANDU reactors : channel simulation, simplistic refuelling scenario study  Research reactor / isotope production reactors Pth >10MWth : started OSIRIS simulation for Nucifer, and high flux ILL reactor simulation  Future reactors (PBMRs, Gen IV reactors, ADS, especially reactors using carbide, nitride, metal or molten salt fuels.  An antineutrino measurement is directly related to the fission process in the reactor core.  An antineutrino measurement can provide in real time information on isotopic fission rates, which can be related to the thermal power and fissile inventory of the reactor. International expert meeting organized by the Department of New Technologies of IAEA, October 26-28. 2008 :

19. March 19. 2009 AAP09 - Brazil - M. Fallot et al. Chooz-B reactors (I, II) 2 core N4 series : 4.27 GW th 13 m 4,5 m Moderator/coolant ‣ pressurized borated water (155 bars) 560 K < T H2O < 620 K ( ρ = 0.7 g.cm -3 ) Moderator/coolant ‣ pressurized borated water (155 bars) 560 K < T H2O < 620 K ( ρ = 0.7 g.cm -3 ) 3,8 m 4,8 m Fuel ‣ enriched UO2 pellet : 1.8, 2.4 and 3.1 % ( ρ = 10.85 g.cm -3 ) 700 K < T UO2 < 1400 K Fuel ‣ enriched UO2 pellet : 1.8, 2.4 and 3.1 % ( ρ = 10.85 g.cm -3 ) 700 K < T UO2 < 1400 K 9 mm 13 mm

20. March 19. 2009 AAP09 - Brazil - M. Fallot et al. PWR N4 : Chooz-B (I, II)-like reactor Fuel element ‣ 317 pellets / h = 4.2 m ‣ Zircaloy coating / 0.6 mm ‣ 3 Enrichments : (1.8, 2.4, 3.1 %.) 12.6 mm ‣ Zircaloy structure ‣ 24 ‘guide’ tubes (poison, instrumentation,..) 214 mm Assembly 264 Core ‣ 3(4) enrichment zones ‣ Refueling 1/3(4) 11 months 205 PWR : full core simulation. Approx. : No control rod reactor driving yet : constant power, Boron diluted into water and mean k eff =1 PWR : full core simulation. Approx. : No control rod reactor driving yet : constant power, Boron diluted into water and mean k eff =1

21. March 19. 2009 AAP09 - Brazil - M. Fallot et al. Neutronics inputs ➡ Systematic effects : ✓ Temperature : Thermalisation & Doppler effect ✓ Neutron Absorbant : Bore ➡ Systematic effects : ✓ Temperature : Thermalisation & Doppler effect ✓ Neutron Absorbant : Bore A matter of neutronics : neutron flux & interaction cross sections (n,x) Fast neutrons Fission spectrum ~ 2MeV Fast neutrons Fission spectrum ~ 2MeV Slow neutrons thermalisation ~ 0.025eV Slow neutrons thermalisation ~ 0.025eV Epithermal domain +moderator 1eV< E n < 1MeV Epithermal domain +moderator 1eV< E n < 1MeV ‣ Φ ~ 3,5.10 14 n.cm -2.s -1 | ~ 0.7 MeV Burnup effect σ (n, f ) 238 U σ (n,γ) 238 U σ (n, f ) 235 U σ (n,γ) 235 U

22. March 19. 2009 AAP09 - Brazil - M. Fallot et al. ‣ Thermal bump displacement : Systematic effects Thermalization : Doppler effect : 0 K 1800 K Boron Cross sections  1/v ‣ Harder neutron spectrum T fuel ➚ ⇒ Resonant captures ➚ Criticity control with soluble boron : ‣ C bore adjusted at each time step t, = 1 Criticity control with soluble boron : ‣ C bore adjusted at each time step t, = 1

23. March 19. 2009 AAP09 - Brazil - M. Fallot et al. Systematic effects Guessed uncertainties on input parameters Inventory : ΔN (%) N fission : Δ(Nf/s) (%) 235 U 238 U 239 Pu 241 Pu 235 U 238 U 239 Pu 241 Pu ΔT m = 30 K 0.5< 0.11.0.8 0.4< 0.1 1.5 ΔT f = 200 K 1.< 0.12.2.51.0.50.81. Δc B = 200 ppm 0.7< 0.12.1.82.42.0.50.8 Δ(mean keff=1 or keff=1) 0.24.40.82.2 Systematic study : ‣ T moderator : 300, 600,... 1200 K ‣ T fuel : 300, 600,.... 1500 K ‣ Boron Concentration : 0, 500,... 3000 ppm mass. Systematic study : ‣ T moderator : 300, 600,... 1200 K ‣ T fuel : 300, 600,.... 1500 K ‣ Boron Concentration : 0, 500,... 3000 ppm mass.  n, En, keff( , Inventory, Nf/s.  n, En, keff( , Inventory, Nf/s. Also studied : - self-shielding effect on inventories and fission rates, - influence of the Monte-Carlo seed Studied effects : of the order of 2% or lower on main fission rates (exc. 238 U)

24. March 19. 2009 AAP09 - Brazil - M. Fallot et al. PWR refueling simulation Constant power : 4.27GW th Boron concentration 1000ppm Mean keff = 1 PWR refuelled every year : 250kg 239 Pu retrieval 900kg 235 U adjunction Constant power simulation of N4 PWR 6.4% Folded by Nucifer response @25m : Preliminary Antineutrino rate/s in Nucifer

25. March 19. 2009 AAP09 - Brazil - M. Fallot et al. Filling all control rods with 238 U 25*205 control rods : +11.5t 238 U => 238 U mass increase of 10% Folded by Nucifer response @ 25m : 235 U : +150kg 239 Pu :+100kg 235 U and 239 Pu fission rates change by -5.5% and +2.5% resp. Antineutrino flux : Change of 0.5% ! Because of 238 U fission rate increase +6-8% : mimick 235 U 238 U inventory 235 U and 238 Pu inventory Fission rates Antineutrino rate/s in Nucifer Preliminary

26. March 19. 2009 AAP09 - Brazil - M. Fallot et al. Removal of the control rods Corresponds to 65kg 239 Pu removal, without changing 238 U and 235 U masses as rods are replaced by fresh U nat Amount of 238 U stays ~ the same, so no compensation by 238 U of 235 U and 239 Pu fission rates variations Preliminary 1.3% Normal refuelling Replacement of the control rods

27. March 19. 2009 AAP09 - Brazil - M. Fallot et al. CANDU reactor specifications (CANada Deuterium Uranium) http://canteach.candu.org  Heavy water as moderator and coolant and natural uranium as fuel  Spatial separation of coolant (in force tubes) and moderator (between force tubes)  On-line refuelling : Plutonium proliferation  Antineutrino flux and spectra : refuelling and 239 Pu proliferation scenarii Calandria moderator Force tubes V.M. Bui PhD, Collaboration with A. Nuttin (LPSC) (*)A. Nuttin, Physor-2006, Study of CANDU Thorium-based Fuel Cycles by Deterministic and Monte Carlo Methods.

28. March 19. 2009 AAP09 - Brazil - M. Fallot et al. Simulation inputs A channel A bundle Fresh fuel 132 Pool 451’1’ Irradiated fuel Moderator Mirror Annular gas CO2 coolant Calandria tube 37pins Force tube  Refuelling of a channel 2/3 fresh fuel and 1/3 irradiated fuel Different simulation steps :  Force tube → c hannel of 12 fuel bundles  1 bundle + mirror → full reactor, homogeneous, infinite (no leak)  Fit boundary mirror dimensions to obtain the CANDU moderation ratio  Temperature dependance : T mod = 300 K T cool = 600 K T fuel = 1200 K  Spatial dependance of the neutron flux  Dwell time def. : threshold 1.05 (A. Nuttin* et al.) : leaks : 3000pcm, absorptions (Boron and impurities) : 2000pcm. T= 300 K for all components Correct mean temperatures Dwell time : 200d

29. March 19. 2009 AAP09 - Brazil - M. Fallot et al. Channel simulation & gross diversion scenario  3 channels (12 bundles) simulations with 100d, 200d and 300d refueling periods  Principle : refuel faster some channels to take Pu away and refuel slower the same number to mask diversion  Isotopic Vector Plutonium: Pu of military quality (VP>90%)  2 “full core” refuelling scenarii - Standard : 400 channels refueled @200 days - Proliferant : 200 channels refueled @ 100d + 200 channels refueled @ 300d to mask diversion  X-checks : collaboration with A. Nuttin et al., Physor 2006 Conf. Proc., comparison between MURE and deterministic code DRAGON Inventory @ refuelling period 100d Inventory @ refuelling period 200d Inventory @ refuelling period 300d

30. March 19. 2009 AAP09 - Brazil - M. Fallot et al. A gross proliferation scenario e in Nucifer (Hz) Fits and sums Folded with Nucifer response @ 25m for 1 channel with different refueling periods : 100d 200d 300d 0 100 200 300 400 0 100 200 300 Time (days) 0 100 200 300 400 Time (days) 400 channels (~ CANDU600-like) refueled every 200d, @ 2 channels per day : adequation between dwell time, daily number of refuelled channels and total number of channels : flat profile of the flux « Normal refueling » : +…+ Adding 400 channels with history shifted by 1 day 0 100 200 300 400 0.02588 Hz => 2236 per day in Nucifer Preliminary Time (days)

31. March 19. 2009 AAP09 - Brazil - M. Fallot et al. Core refuelled @ 100d and 300d Folded by Nucifer response @ 25m : 200 channels refuelled every 100d, 200 channels every 300d, @ 2 channels per day 3.5% discrepancy in the antineutrino rate !!! Nucifer reaches 1% statistic precision after 1 day 3.5% discrepancy in the antineutrino rate !!! Nucifer reaches 1% statistic precision after 1 day Fission rates : Normal refuelling : 54.1% 235 U - 45.9% 239 Pu Diversion scenario : 60,1% 235 U - 39,9% 239 Pu Time (days) 0 100 200 300 400 +660kg 235 U after 200x100d + 200x300d -430kg 239 Pu including 152kg from 100d channels 0.02497 Hz => 2157 per day 0 100 200 300 400 Time (days) 0.02588 Hz => 2236 per day +600kg 235 U after 400x200d -464kg 239 Pu

32. March 19. 2009 AAP09 - Brazil - M. Fallot et al. Conclusions and outlooks  A set of performant tools (MURE+BESTIOLE+databases…) to compute the antineutrino energy spectrum and flux under various conditions : experiment and reactor simulations  Neutron capture and long-lived fission products contributions to the spectrum : need to be evaluated carefully and compared with Kopeikin’s et al. results  Simulation of different kinds of reactors, including Chooz-B ones for the Double Chooz experiment  First gross proliferation scenarios studied, with PWR and CANDU reactors, including the response of the Nucifer detector placed at 25m from the cores  Nucifer sensitivity in 239 Pu content : ~+-65kg 1% change in the measured antineutrino flux by Nucifer @25m of a PWR core, 1% statistical accuracy reached in 4days by Nucifer in these conditions

33. March 19. 2009 AAP09 - Brazil - M. Fallot et al. Backup Slides