NON-PROLIFERATION AND
REACTOR MONITORING
Yeongduk Kim
Center for Underground Physics, IBS
Sejong University
2016. 7. 4.
Neutrino 2016, LONDON
Reactor Monitoring with neutrinos
2
l  Antineutrino detection can monitor ;
1.  Reactor Power
2.  Fissile content of the reactors.
l  Such monitoring may be useful for the IAEA’s reactor safeguards and
Non-Proliferation since IAEA can’t directly measure fuel contents
while fuel is loaded.
Historical measurements by SONGS to see the neutrino rates dependence on the fuel –
by Bernstein.
3
Milestones
1.  Kurchatov, Mikaelian et al. ~1990
l  The correlation of the antineutrino signal with the thermal power and the burnup was demonstrated by the Bugey and Rovno experiments.
2.  LLNL, Sandia National Laboratories. Bernstein et al., ~ 2000
l  The LLNL/SNL has installed and operated a prototype detector at the 3.46
GWth San Onofre Nuclear Generating Station (SONGS) in Southern
California.
3.  New short baseline detectors ~ 2010
l  With the reactor neutrino anomaly, dozens of proposals for short baseline
neutrino experiments are proposed. Many of these experiments can work for
reactor monitoring too.
4.  Remote Sensing ~ 2020 ?
l  A large (> kton) detector can be used to identify unknown reactor activity.
World neutrino map is available. New prpposals.
4
Reactor power vs neutrino spectra
l  The antineutrino production rate varies with fissioning isotopes : PLWR example
X.B. Ma et al., Phys.Rev. C88 (2013) no.1, 014605 235U
238U
239Pu
241Pu
E(fission, MeV)
201.9
205.5
211.0
213.6
N(nu) (E>1.8MeV)
1.92
2.38
1.45
1.83
E(nu) (MeV)
5.23
7.04
3.80
4.96
Calculated according to
Huber Phys.Rev. C84
(2011) 024617
Burn-up & Fuel composition
5
Calculated according to Huber, Phys. Rev. C84 (2011) 024617
S(0)/S(500)
T=0
S(0)
T=500
ROVNO exp. Klimov et al., Atomic Energy 76, (1994)
S(500)
Neutrino
Event Rate
~ 1 event/day
for
1GW reactor
& 1ton detector
@ 1km
6
Experiments for reactor monitoring & safeguards
Exp
P
Units
MW
Nucifer
70
mTC
Detector
L
Time
Rate
S/B
(m)
(days)
On-Off
/day
Gd-LS
7
145-106
280
0.25
20
B-PS
5
PANDA
3420
PS
35.9
30-34
~22
?
DANSS
3000
PS
11
P2.075
iDREAM
~3000
Gd-LS
?
P2.088
NuLAT
20
6Li-PS
4.7
Vidarr
1600
Gd
60
STEREO
57
Gd-LS
10
P1.089, P3.062, P3.072,P3.073
Neutrino-4
90
Gd-LS
7
P1.080
SOLID
72
CHANDLER
60
6Li+PS
5.5
PROSPECT
85
6Li-LS
7-12
NEOS
3000
Gd-LS
24
WATCHMAN 3758
Gd-W
~10km
~0.2
6LiF:ZnS 5.7
PS:Plastic Scintillator,
Posters @ Neutrino 2016
P1.084
P1.081, P3.059, P3.060
P1.053, P3.054, P3.055,P3.056
180-30
2000
LS:Liquid Scintillator, W:Water
23
P3.052
7
Detection of antineutrinos
ν e + p → e+ + n
1-10 MeV
n +155,157 Gd →156,158 Gd + γ s(~ 8MeV )
n + 6 Li → 4 He + 3 H + 4.8MeV
4.8 MeV alphas
8 MeV gammas
~10 micro s
t
l  Bowden’s talk on tomorrow (Tue.) 14:50
“Review of short-baseline reactor antineutrino experiments”
Will cover Neutrino-4, STEREO, PROSPECT, DANSS, Chandler
I don’t have enough time to cover all the experiments.
l  miniTimeCube (mTC)
l  PANDA
l  iDREAM
Nucifer
8
PRD 93, 112006 (2016)
Reactor(containment(building(
0(m(
Water(pool(
Core(
8(8(m(
Nucifer(
8(11(m(
Concrete(founda/on(slab(
Singles (Reactor OFF)
Singles (Reactor ON)
0
Counts Per Bin (arbitrary unit)
10
−1
10
−2
10
−3
10
0
500
1000 1500 2000 2500 3000 3500 4000 4500
Total Charge (pe)
20
P=70 MWth Research reactor at CEA Saclay.
L∼7 m, at the lowest reactor level
V=850L Gd-LS
Low overburden, muon flux attenuation of 2.7.
Even with high reactor related gamma
background, surprisingly precise neutrino rate :
281 ± 7(sta) ± 18(sys) ν / day à 7% error
Neutrino candidates
Exponential Fit
15
Event Rate Per Day
l
l
l
l
l
10
5
0
−5
0
50
100
∆ t (µs)
150
200
9
Sensitivity to plutonium content
340
95% CI
Data
458 g 239Pu
data
Neutrino Rate [/day]
320
300
1370 g
95% confidence
2390 g
3530 g
239
Pu
239
Pu
239
Pu
4460 g 239Pu
6090 g 239Pu
280
l  238U(82kg)+235U(20kg) loaded.
(19.75% enriched)
l  92% of fissions from 235U.
l  14kg 235U and 450 g of 239Pu
on average for 21 day cycle.
260
ß Various amount of 239Pu are
added in simulation to see the
effect of neutrino rate change.
240
220
200
0
50
100
150
Time [days]
200
250
l  Fuel burn-up effect : only 3.5 % lower than initial load
à No sensitivity to diversion of fuel (undeclared retrieval of Pu)
l  Reversely, replacing 235U by 239Pu
à 1.5 kg of additional Pu can be identified by 95% confidence.
Cf. 0.4% increase in neutrinos with 20 kg of Pu removal from 3GW reactor.
10
Search for Oscillations with Lithium-6 Detector
ü  P=60-80 MW, BR2 at SCK-CEN (Belgium)
ü  3D composite scintillator segmented detector
§  5cm PVT cube scintillator with 6LiF:ZnS(Ag)
§ Technology fulfilling the safety requirements
ü  Successful run of first real scale prototype SM1 in 2015
Stable rates of EM and neutron signals
ü  SoLid Phase I (2017-2019)
§  from 5.7m from core
§  1.6t fiducial mass
MC signal
EM
Correlated bkg (data)
Data
neutron
Accidental bkg (data)
Can identify neutrons in tens of
million events !
High segmentation improves
background rejection
Phase I
11
l
l
l
l
l
l
NuLat: 6Li scintillator and a ROL
Raghavan Optical Lattice (ROL)
15x15x15 cubes 6Li-loaded plastic scintillator
Each 2.5” on a side (total volume 0.86 m3)
Instrumented with 600 2” PMTs.
Pulse shape discrimination
Light transmit by total reflection.
Demonstrating NuLat with the Rol53
l
l
l
A 5×5×5 Cubes with 150 PMTs.
Demonstrate reactor monitoring by
deploying at commercial power plant.
Measure backgrounds by deploying at
NIST in NuLat shielding
Vidarr (Ecal)
12
•  Based on T2K-ND280 ECal
•  Plastic scintillator, WLS fibre, MPPCs
•  Lead replaced with Gd.
•  M~1 ton active mass
•  Deployed @ Wylfa power station, UK
•  P=1.6 GWth , L ~60 m from the core.
•  Reactor start-up observed.
l
l
Upgraded Detector - Vidarr
l  Custom built readout & DAQ
l  Replace repurposed T2K electronics.
l  ~100% live-time, lower energy thresholds, greater sensitivity
l  Working with John Caunt Scientific Ltd to deliver commercial re
ady device.
Collaboration with National Nuclear Lab Ltd (NNL)
l  Anti-neutrino flux, core isotopes fractions, 5MeV bump study.
DQ issues
NEOS (Neutrino Experiment for Oscillation at Short baseline)
13
•  Hanbit Nuclear
Power Plant
●
RENO
near
detector
l NEOS at the!
5th reactor!
Reactor
Core
Liquid Scintillator (LS) 1000 L,
LAB + Altima-Gold F (9:1) +
38 8’’ PMTs in mineral oil.
0.5 % Gd loaded.
Borated PE (10 cm)
10 cm lead shield
l
l
l
l
l
Plastic scintillator for muon veto
P=3 GWth, located at RENO Site.
L∼24 m, Detector inside Tendon Gallery
V=1000L, Gd-LS
~8m overburden, at least 3.5 m of soil.
Took 6 month data and removed detector
due to Tendon maintenance.
14
High S/B ratio due to overburden
NEOS Preliminary
Reactor on: ~ 2000/day
Reactor off: ~ 82/day
Reactor on
Reactor off
𝛾-like
Signal / Backgrounds ~ 23
Cut off
n-like
15
Notable results (Details by Yoomin Oh’s poster P3.052)
1. Data/MC shows ~ 5MeV bump similar to RENO/DayaBay/DC.
Compared with Huber
2. Data(1st month)/Data(6th month) shows increase as expected from the Burn-up.
Reactor monitoring sensitivity :
2000 neutrinos/day à 0.4% statistical
error for 1month data à sensitive to 20
kg Pu removal from a reactor in a
month data !
Ultimate reactor neutrino spectra ?
16
l
l
l
A new ~ 2ton size detector with photocathode coverage > 70% at
shorter baseline (~15m) can have an energy resolution better than 3%
and high statistics (>10000 events/day)
Can study 5 MeV bump, potential other deviations from the prediction,
and E>7MeV region precisely. (maybe useful for mass hierarchy exp.)
Tendon Gallery may be extended in a new reactor under consideration
in Korea or China for complete burn-up measurements.
Experiments for Non-proliferation, remote sensing
17
l  ‘‘NUDAR’’ (NeUtrino Direction and Ranging), points that measurement of the
observed energy spectrum can be employed to locate a neutrino source from even
a single detector thanks to unique energy-dependent character of neutrino
oscillations and can be improved still further by the use of multiple detectors.
Lasserre arXiv:1011.3850, Jocher et al., Physics Reports 527 (2013) 131–204,
Askins et al., arXiv:1502.01132
l  The Water Cherenkov Monitor for ANtineutrinos (WATCHMAN) is designed to satisfy a
US Nonproliferation initiative.
l  Proposed as a demonstration of remote reactor monitoring for future nonproliferation
and cooperative monitoring agreements.
18
WATCHMAN deployment options
The WATCHMAN baseline deployment: a kiloton scale gadolinium-doped Water Cherenkov
antineutrino detector deployed 10-20 km from a US or UK reactor.
Reactor Location
Thermal Power (MWt)
Detector Location
Standoff
Overburden (mwe)
Approval status
Preferred
Alternate
PERRY Reactor
Perry Ohio
Hartlepool, England
3875
2 x 1575
Morton Salt/IMB mine
Painesville, Ohio
13 km – only US at a suitable
distance from a deep mine
1430
Boulby underground
science lab
~25 km
Morton Salt has approved
installation
Strong encouragement from mine
operators and science directorate.
3000
The baseline WATCHMAN design
19
l
3.5:1 kTon total:fiducial
l
Gd-H2O with recirculation
l
20% PMT coverage
l
Detector geometry in the RATPAC simulation environment
(B. Land, UC Berkeley)
Option for water-based
liquid Scintillator.
Close-up of Veto PMT Wall
78 feet
Example deployment at the Morton Salt Mine in the United States
Summary
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l
l
l
l
Neutrino detector near reactors can be a new tool for reactor
monitoring.
Compact, portable detector with segmentation is under development
for ground level monitoring. (Nucifer analysis shows promising)
More precise reactor neutrino spectra can show detail understanding
of neutrino production inside the reactor. (NEOS demonstrates)
Remote sensing with a 1-1000 kton WBLS neutrino detector can be
used to sense some unknown reactors, so for nuclear safeguards.
Backups
21