EXPERIMENTAL AND SIMULATION ACTIVITIES AROUND
REACTOR ANTINEUTRINOS AND DECAY HEAT
M. Fallot1 1 ERDRE group, SUBATECH (CNRS/IN2P3, Ecole des Mines de Nantes, Université de Nantes), 4, rue A. Kastler, 44307 Nantes cedex 3, France, fallot@subatech.in2p3.fr + Many thanks to J.-­‐L. Tain, A. Porta and A. Algora for the slides and inputs provided for the TAS part On-behalf of the TAS Collaboration for the data part of this talk
J. Agramunt1, A. Algora1, J. Äystö4, V.M. Bui2, D. Cano-Ott5, C. Domingo-Pardo1, V. Eloma4, E. Estévez1, T.
Eronen4, M. Fallot2, W. Gelletly3, G. Giubrone1, J. Hakala4, A. Jokinen4, M.D. Jordan1, A. Kankainen4, E.
Mendoza5, F. Molina1, ,I. Moore4, S.E.A. Orrigo1, A. Pérez1, Zs. Podolyák3, H. Penttilä4, A.Porta2, P. H. Regan3,
S. Rice3, J. Rissanen4, B. Rubio1,J.L. Taín1, E. Valencia1, C. Weber4, A. Zakari2 + IGISOL people
1 IFIC, CSIC-Univ. Valencia, Valencia, Spain
2 Subatech, CNRS/IN2P3, Univ. Nantes, EMN, Nantes, France
3 Univ. Surrey, Guilford, UK
4 IGISOL, Univ. Jyväskylä, Finland
5 Ciemat- Madrid, Spain
Outline
Fission Product Beta Decay properties in Nuclear Reactors:
•  Reactor An+neutrinos: for par+cle physics (Double Chooz) and reactor monitoring •  Pandemonium Effect and Total Absorp+on Spectroscopy Technique •  Latest Published Results: Decay Heat •  Latest Published Results: Reactor An+neutrinos •  Preliminary Results from Latest Experiment ERDRE Group - SUBATECH
•  Forthcoming Experiments 2
Nuclear Reactors
Future reactor criteria
safety, optimized waste management, sustainability, economy, non proliferation
UOx Pu (MOX) Fission process gives thermal energy: n + 235U -­‐> 236U* -­‐> PF1 + PF2 + neutrons (200 MeV) Fission Products (FP) are neutron-­‐rich nuclei, undergoing β -­‐ decay A
Z
A
Z X
X " Z +1A Y + e - + # e
β-
!
  The released γ and β contribute to the “decay heat”   The an+neutrinos escape and can be detected   β-­‐n emi[ers: delayed neutron frac+ons γ
γ
A
Z+1 Y
Reactor monitoring with antineutrinos
235U
239Pu
Ef (MeV)
201.9
210.0
<Eν > (MeV)
1.46
1.32
<Nν>
(E>1.8MeV)
5.58
(1.92)
5.09
(1.45)
Fission Products (FP) are neutron-­‐rich nuclei, undergoing β -­‐ decay A
Z
!
239Pu
235U
X " Z +1A Y + e - + # e
Reactor monitoring with antineutrinos
235U
239Pu
Ef (MeV)
201.9
210.0
<Eν > (MeV)
1.46
1.32
<Nν>
(E>1.8MeV)
5.58
(1.92)
5.09
(1.45)
Fission Products (FP) are neutron-­‐rich nuclei, undergoing β -­‐ decay A
Z
X " Z +1A Y + e - + # e
!
239Pu
235U
⇒  Power Reactors are copious an+neutrino emi[ers => neutrino physics = oscillation
parameter search: θ13, search for sterile neutrinos (reactor anomaly)
⇒  Use the discrepancy between an+neutrino flux and energies from U and Pu isotopes to infer reactor fuel isotopic composition => reactor monitoring, non-proliferation
and interest of the IAEA
UPDATE
*ArXiv : hep-exp/0606025
*http://doublechooz.in2p3.fr/Public/French/welcome.php
DOUBLE CHOOZ EXPERIMENT*
Mixing angle θ13 measurement (limit) + non-proliferation goal
ν flux
Normalization
@400m
ν
oscillation
@1050m
2 identical
8.3t targets
νe
νe,µ,τ
2 PWR-N4
2x4.27 GWth
1021 νe/s
  DC phase 1 (2011-13) : Far detector only, sin2(2θ13)<0.06 (1,5 years, 90% C.L.)
6
  DC phase 2 (2013-15) : Far + near sites, sin2(2θ13)<0.03 (3.5 years,90% C.L.)
UPDATE
DOUBLE CHOOZ:
Full core simulations with the MURE code, with a
follow-up of thermal power and boron concentration
Numerical computation of the systematic error
associated to the fission rates with MURE over the fuel
cycle
A. Onillon’s PhD
Total reactor error: 1.8%
Dominated by σBugey
Rate + Shape Analysis:
sin2(2θ13) = 0.109±0.030(stat)±0.025(syst)
Impact in θ13 knowledge by DC
Combined effect: sin2(2θ13)>0 @ 99.9%C.L.
Y. Abe et al Phys. Rev. Lett. 108, 131801, (2012)
Y. Abe et al. Physical Review D 86, 052008, (2012)
7
PROLIFERATION SCENARIOS WITH ANTINEUTRINOS
  Reactor simulations with MURE:
  Characteristics of the antineutrino emission from diversion scenarios, taking into account reactor
physics, for different types of reactor and fuels (actual and future)
French N4 PWR full core: Double Chooz:
*MCNP Utility for Reactor Evolution, O.
Méplan et al. ENC Proceedings (2005)
Developped by CNRS labs for Generation IV
reactor simulations
CANDU 600 channels
with different refueling periods
Na-cooled Fast Breeder
VHTR pebbles and full
core
Non proliferation scenario studies
Detailed reactor simulations to compute antineutrino emission associated to
diversion scenarios, taking into account accurately reactor physics
French N4 PWR full core
Core
Flux
in Nucifer at 25m of a
205detected
Assemblies
REP N4 (1.1t target)
*MCNP Utility for Reactor Evolution, O.
Méplan et al. ENC Proceedings (2005)
Developped by CNRS/IN2P3/IPNO and LPSC
for Generation IV reactor simulations
264 fuel rods
‣  3 Enrichments
CANDU 600 channels The summation method~6.5%
is the only allowing these with calculations:
different refueling periods 214
Short-term
results:
12.6 mm
mm
2 PhD defended (Van Minh Bui: CANDU, Sandrine Cormon: CANDU, VHTR/PBR, Na214
12.6 mm
FBR) in October andmm
December 2012:
-  Proliferation
scenario results to give to IAEA
CANDU 600
channels
OSIRIS research reactor
Fast Breeder (on-going)
with Na-cooled
different refueling
of CEA/Saclay
VHTR
periods
-  Antineutrino spectra calculations for innovative fuels
(+ pebbles and
full core (on-going)
Zircalloy
participation of a Tokyo-Tech
PhD student, T. Shiba)
Calandria
tube
Annular gas
CO2
Force
tube
Moderator
fuel
Hf
Hf
Control
rods
Hf
Hf
Hf
Hf
coolant
37pins
irradiation
B B
e e
pool
Mirror
B B B B B
e e e e e
Beryllium wall
Reactor: 57 × 57 × 60 cm
Antineutrino Spectra: Fission Product « Summation » Method
*MURE: MCNP Utility for Reactor Evolution:
-
-
-
-
Computes the fission product distributions to couple with
beta decay nuclear databases
Includes off-equilibrium effects
Prediction of any antineutrino energy spectrum for
individual fissible nuclei or full reactor cores, for neutrino
physics or non proliferation
One of the only alternatives to β-spectra measured @ ILL**
*MCNP Utility for Reactor Evolution:
http://www.nea.fr/tools/abstract/detail/nea-1845.
** K.Schreckenbach et al., phys. Lett. B, 160,1985, 325-330;
Hahn et al., phys. Lett. B, 218,1989, 365-368.
But Pandemonium effect:
Requires new measurements of fission product beta decay
properties
⇒  Selection of a list of fission products contributing each by more
than 4% in 2-6MeV bins.
Antineutrino experiments use newly converted
spectra from the ILL reference measurements
instead: Th. Mueller et al. Phys. Rev. C 83, 054615 (2011)., P. Huber,
Phys.Rev. C84 (2011) 024617
⇒ « Reactor anomaly »: all reactor neutrino experiments are below
the prediction (G. Mention et al. Phys. Rev. D83, 073006 (2011)).
10
TAS Technique
Pandemonium effect**:
Due to the use of Ge detectors to measure the decay schemes: lower efficiency at higher
energy
→ underestimate of β branches towards high energy excited states: overestimate of the high
energy part of the FP β spectra
Solution: Total Absorption Spectroscopy (TAS)
Big cristal, 4π => A TAS is a calorimeter !
Picture from A. Algora
** J.C.Hardy et al., Phys. Lett. B, 71, 307 (1977)
11
  12 BaF2 covering ~4π
  Detection efficiency of γ ray
cascade ~ 100%
  Si detector for β
TAGS developed by the Valencia team (Spain, J.L. Tain, A. Algora et al.) : Proceedings of the Int.
Conf. For nuclear Data for Science and technology (ND2010)
RESULTS
TAGS MEASUREMENTS @ JYVÄSKYLÄ UNIV. (JYFL)
  IFIC of Valencia (J.L. Tain et A. Algora et al.)
Reactor Decay Heat in 239Pu: Solving the γ Discrepancy in the 4–3000-s Cooling
Period,
A. Algora et al., Phys. Rev. Lett. 105, 202501 (2010)
⇒  Taking into consideration the TAS data of the
measured @ Jyväskylä
102;104–107Tc, 105Mo,
and
101Nb
isotopes
⇒  i.e. correcting 5 nuclei out of 7 for the Pandemonium effect
β-feeding distribution
105Tc
Proposed correction
12
Impact of the results for 239Pu:
electromagnetic component
RESULTS
Inclusion of the latest TAS data in the Antineutrino Summation
Spectra:
  With the recently measured TAS data set by Algora et al. Phys. Rev. Le[. 105, 202501 (2010): « New an+neutrino energy spectra predic+ons from the summa+on of beta decay branches of the fission products », Phys. Rev. Le[. 109, 202504 (2012), M. Fallot, S. Cormon, M. Es+enne et al. ERDRE group

13
239;241Pu
energy spectra: no+ceable devia+on from unity observed in the 0–6 MeV energy range reaching an 8% decrease.   238U energy spectrum: effect reaches a value of 3.5% at 2.5–3 MeV.   235U: 1.5% at 2.5–3.5 MeV, expected since these nuclei are a small contribu+on to the 235U spectrum. Ratios between two spectra built with
the data set described above over the
same but the new TAS data (JEFF).
RESULTS
Inclusion of the latest TAS data in the Antineutrino Summation
Spectra:
  With the recently measured TAS data set by Algora et al. Phys. Rev. Le[. 105, 202501 (2010): « New an+neutrino energy spectra predic+ons from the summa+on of beta decay branches of the fission products », Phys. Rev. Le[. 109, 202504 (2012), M. Fallot, S. Cormon, M. Es+enne et al. energy spectra: no+ceable devia+on from unity observed in the 0–
6 MeV energy range reaching an 8% decrease.   238U energy spectrum: effect reaches a value of 3.5% at 2.5–3 MeV.   235U: 1.5% at 2.5–3.5 MeV, expected since these nuclei are a small contribu+on to the 235U spectrum. ERDRE group

14
239;241Pu
Ratios between two spectra built with the
data set described above over the same
but the new TAS data (JEFF).
⇒  Shows the important role of the Pandemonium nuclei in the ν summa+on spectra ⇒  The summation spectra are among the only ways to estimate the antineutrino spectra
independently from the measured ILL integral β-spectra
⇒  The summation spectra are the only ones allowing to compute the antineutrino
emission from future reactors and fuels ⇒  New measurements required New measurements @JYFL (Jyväskylä,Finland)
  7 nuclei have been already measured at JYFL of Jyväskylä (Finland), analysis is on-­‐going (J.L.Tain et al. Proceedings of the Int. Conf. ND2010): 86Br, 87Br, 88Br, 91Rb, 92Rb, 93Rb, 94Rb Why JYFL: good selec+on of the measured nucleus needed → IGISOL* + penning trap JYFLTRAP** *J.Ärje et al., NIM A 247,431 (1986)
**V.S.Kolhinen et al., NIM A 528,776 (2004)
15
TAS measurements for reactor antineutrinos
  Antineutrino Spectra with the Summation method:
  List of nuclei of interest for reactor antineutrinos: neutrino physics + non-proliferation
  25 nuclei in common with the priority list for decay heat (WPEC (IAEA/NEA) Subgroup
25) : Consultants’ Meeting on TAGS @ IAEA Headquarters (Janv. 2009)
⇒  Exp. Proposal by SUBATECH - IFIC: reactor antineutrinos: experiment accepted in 2009:
another 9 nuclei, planned in 2013@JYFL
  Experiment at IGISOL-JYFL with JFLTRAP in 2009 on beta-delayed
neutron emitters:
⇒  Could already measure 92Rb, 93Rb extracted from the neutrino proposal ! Reactor
antineutrino Priority 1
+ 92Rb: Priority 2 for Decay Heat in U/
Pu cycle and Priority 1 in Th/U cycle
PhD Thesis work:
•  Z. Issoufou (Subatech – Nantes)
Preliminary Results for 92Rb
Data analysis:
Cleaning of the raw data from
contaminants (background and pile-up)
to obtain the clean spectra (blue)
Calculation of level energy feeding through the
resolution of the inverse problem
di=ΣRij*fj
Clean data
Response matrix Level feeding
From GEANT4
Detector simulation
Clean spectrum
On-going…
PhD Thesis work:
•  Z. Issoufou (Subatech – Nantes)
from A. Porta - Subatech
Example of
Reconstructed
spectrum from feeding
estimation
17
“Decay properties of beta delayed neutron emitters”
and more
•
•
•
•
•
•
Experiment at IGISOL-­‐JYFL with JYFLTRAP TAS measurements for 94Rb, 91Rb, 88Br, 87Br, 86Br (For delayed neutron measurements with BELEN see: J.L. Tain previous JEFF mee+ng) Priority 1 for Decay Heat calcula+ons (U/Pu and Th/U cycles): 86-­‐88Br, 94Rb Determina+on of gamma-­‐neutron compe++on Γγ/Γn: 94Rb, 88,87Br Normaliza+on of Rudstam γ spectral data: 91Rb βn
βn
βn
PhD Thesis work:
•  E. Valencia (IFIC-Valencia)
•  S. Rice (University of Surrey)
from J.-L. Taín – IFIC-Valencia
The case of 94Rb
Analysis: Spectra must be
corrected for several
contaminations:
•  Pulse pileup
•  Daughter (94Sr)
•  Grand daughter
(94Y)
•  βn final nucleus
(93Sr)
•  Neutron
interactions
Par+cularity of these measurements: delayed neutron induced background. Neutron sensi+vity calculated with Geant4: εn ≈40% PhD Thesis work:
•  E. Valencia (IFIC-Valencia)
from J.-L. Taín – IFIC-Valencia
The case of 94Rb
Results: I ! n = 10.2%
Considerable
“Pandemonium”
effect: intensity
redistribution
and loss
HR
I !"
= 59.8%
TAS
I !"
= 89.8%
Considerable
γ-intensity
above Sn
I !"
I !n
PhD Thesis work:
•  E. Valencia (IFIC-Valencia)
! 0.4
E x >Sn
(usual assumption: 0)
from J.-L. Taín – IFIC-Valencia
Conclusions
Motivations: safety, non-proliferation, neutrino physics
From the latest published results we see that:
  Pandemonium nuclei play a major role in the reactor decay heat coming from FPs
in the first 10 thousands of seconds after reactor stops and TAS measurements of
these nuclei will allow to improve drastically the predictiveness of decay heat
calculations ;
  Pandemonium nuclei play a major role in the estimate of the antineutrino spectra using
the summation method and TAS measurements of these nuclei could allow us to
improve drastically the predictiveness of these spectra ;
Analysis on-going:
ERDRE group
  Results from the latest experiment on the beta-n emitters performed @ JYFL are
coming soon: !! see already 94Rb preliminary results shown @JEFF meeting !! ;
21
  Results from 1st priority nuclei for antineutrino spectra are coming soon ;
Mini-workshop about antineutrino spectra held in Valencia in Nov. 2012
JEFF-GEDEPEON nuclear data meeting Nov. 2012 + 5 abstracts accepted @ND2013
Outlooks
2013:
  DChooz continuation: non-proliferation aspects, validation of the MURE simul.
  Another 9 nuclei to be measured in 2013 @ JYFL for antineutrinos & decay heat
  A new PhD student on decay heat: both experimental beta decay measurements +
decay heat simulation including the new data: M. Lenoir, EAMEA-SUBATECH
  Next ESARDA meeting in May In Bruges, antineutrino sub-WG meeting foreseen =>
toward a roadmap for IAEA about antineutrino detection for reactor monitoring
⇒  Motivate our demand for 2013 (10kE simulation + 10kE experimental activities)
Longer term outlooks:
  Still associate simulations and new decay data
ERDRE group
  Participation of the Subatech group to CHANDA, in the FP beta decay properties
part ;
22
  Participation to the IAEA beta-n CRP ;
  Prepare for future experiments @ other facilities: ALTO for instance, SPIRAL2
  …
Backup
Originally : Method based on individual fission
product beta decay summation
N" (E" , t ) = $ Yn ( Z , A , t ) # S" ,n ( Z , A , E" )
fissile
mat. + FY
Core
neutron
geometry
flux !
n
exp.
spectrum
β-spectra database :
Core Simulation
Evolution Code MURE
β- decay rates
Yi ( Z , A , t )
!
models
β-branch
TAGS, Rudstam et al.,
ENSDF, JEFF, JENFL, …
other evaluated nuclear databases
weighted Σ
β- /νe spectra
S" ,i ( Z , A , E" )
Total νe and β - energy spectra
!
with possible complete error treatment
+off-equilibrium effects Full core level with MURE*
  The MURE Code (MCNP U+lity for Reactor Evolu+on) :
-  C++ interface to the Monte Carlo code MCNP (static particle transport code)
-  Open source code available @ NEA: http://www.oecd-nea.org/tools/abstract/detail/nea-1845
-  Used for the 1st phase of the Double Chooz experiment
Double Chooz reactor paper in preparation
Static
computation
t=0
MCNP
+ evolution s
condition (power …)
Static
computation
t = Δt1
MCNP
+ evolution s
condition (power …)
Static
computation
t = Δtx
MCNP
Material evolu,on: Resolu,on of Bateman differen,al equa,ons decays
reactions induced by neutron
 Outputs provided: keff, neutron flux, inventory, reaction rates (fission, capture, …) + adapted to
compute antineutrino spectra
  Development of a complete core simulation with a follow up of core operating parameters
  Can be used also for simple geometries: ILL spectra computation
From A. Onillon
25
UPDATE
DChooz: Antineutrino flux and spectrum prediction
-  Far detector data only
-  No-Oscillation ⇒ reactor flux prediction via core simulations
-  Normalisation to the Bugey-4 cross-section with far detector
only
⇒ Reduced reactor systematics:
Full core simulations with the MURE code, with a follow-up of
thermal power and boron concentration
Numerical computation of the systematic error associated to
the fission rates with MURE over the fuel cycle
⇒  Fractions of fissions per isotope 235U=49.6%, 239Pu=35.1%,
241Pu=6.6%, and 238U=8.7% and the fission rate covariance
matrix.
⇒  Resulting relative uncertainties on the above fission
fractions are ±3.3%, ±4%, ±11.0% and ±6.5%
26
Total reactor error: 1.7%
Dominated by σBugey
Accurate reactor simulations keep the contribution of fission fraction uncertainties low
"
"
28 & 29 October 2010: first meeting of the Novel Approaches /Novel Technologies Working
Group: IAEA participants, inspectorates from IAEA, EURATOM, ESARDA were invited to
present their needs
33rd ESARDA ANNUAL MEETING @ Budapest 2011:
Novel R&D items list (more than 44 items !) discussed in NA/NT WG
"
Creation of a Sub -Working Group devoted to the antineutrino probe:
the membership of the sub-working group is open to associated members (from non-EU
countries) and individuals
A place of discussions and contacts with agencies, researchers from many fields, …
⇒  Antineutrino Monitoring sub-group as broad as possible !
(contact: fallot@subatech.in2p3.fr)
⇒  Towards a roadmap for IAEA about reactor neutrino detection for reactor monitoring
"   34rd ESARDA ANNUAL MEETING @ Luxemburg 2012: overview about antineutrino probe for
safeguards
Next WG meeting: 35rd ESARDA meeting: May 2013, Bruges, Belgium
Key words: an+neutrino detec+on, R&D, compact detectors, PSD, actual and future reactors (Gen IV, ADS, research…), simula+ons, prolifera+on scenarios, NUCLEAR DATA … "
27