Safeguards and Cooperative Monitoring of
Reactors With Antineutrino Detectors
Lawrence Livermore National Laboratory
Adam Bernstein P.I.
LLNL
Sandia National Laboratories
Nathaniel Bowden P.I.
This work was partially performed under the auspices of the US Department of Energy by the University of
California, Lawrence Livermore National Laboratory, under contract No. W-7405-Eng-48.
CRS 3/24/2016 # 1
How Does The IAEA Monitor Fissile Material Now ?
(1-1.5 years)
1. Check Input and
Output
Declarations
2. Verify with Item
Accountancy
3.Containment and
Surveillance
(months to years)
1 ‘Gross Defect’
Detection
2 Continue Item
Accountancy
3. Containment and
Surveillance
(months)
(forever)
1 Check Declarations
2 Verify with Bulk
Accountancy:
Operators Report Fuel Burnup and Power History
No Direct Pu Inventory Measurement is Made Until the Fuel is Reprocessed
LLNL
Antineutrino Detectors Offer Unique Advantages for Reactor
Safeguards
A. Measure fissile content directly
B. Measure thermal power, which constraints fissile content
C. Operate continuously, nonintrusively, and remotely
• our experimental work has already demonstrated B
and C with a simple detector, and our data are fully
consistent with A
• This approach complements Item Accountancy of
assemblies with Bulk Accountancy of plutonium at
the earliest possible moment in the regime
LLNL
Properties of Antineutrinos
Rates near reactors are high
- 0.64 ton detector, 25 m from
reactor core
- Core thermal power = 3.46 GW
- 4000 events/day/0.64 ton with a
100% efficient detector
- Our detector is about 10% efficient and
counts 400 events per day
Rate and energy spectrum are sensitive to the isotopic
composition of the core
• 200-250 kg of new plutonium is generated in a typical cycle
• Real data and detailed reactor simulations show a
reduction in the antineutrino rate of about 8% through a
500 day cycle caused by Pu ingrowth
LLNL
The Basic Technical Idea
A.
Monitor operating reactors with ~1 m3 antineutrino detectors placed a few tens of meters
from the reactor core
B.
Compare measured and predicted antineutrino rate or spectra to identify changes in fissile
content.
Pu-241
U-238
Daily antineutrino count rate
LLNL
How Does it Work Operationally ?
100% of rate
90-95% of rate
Non-antineutrino backgrounds
days
Persistent antineutrino signal
from distant reactor
LLNL
The systematic shift in inventory is reflected by the
changing antineutrino count rate over time
Testing the Idea at a Reactor Site
25 meters standoff from core
20 meter heterogenous overburden
LLNL
A crack team of
investigators
Cutaway Diagram of the LLNL/Sandia Antineutrino Detector
Currently operational:
4 cells with 640 kg of scintillator;
quasi-hermetic muon veto; hermetic water shield
LLNL
Detection of Antineutrinos
• The antineutrino interacts with a proton producing…
– A 1-7 MeV positron
– A few keV neutron
– mean time interval 28 sec
• Both final state particles deposit energy in a scintillating detector over
10s or 100s of microsecond time intervals (depending on the medium)
• Both energy depositions and the time interval are measured
LLNL
Daily Power Monitoring Using Only Antineutrinos
100
500
80
400
60
Net 400 events/day
300
20
200
Predicted count rate using
reported reactor power
Observed count rate, 24 hour average
Reported reactor power
100
0
2/28/05
3/7/05
3/14/05
Date
LLNL
40
3/21/05
3/28/05
0
-20
Reactor Power (%)
Counts per day
600
A Preliminary Indication of the Burnup Effect
600
Counts per day
550
500
450
400
Jun '05
Predicted
Data
Fit to data
Jul '05
Aug '05
Sep '05 Oct '05
Date
LLNL
Nov '05 Dec '05
Current Work: Compare Effectiveness against Diversion
Scenarios With and Without an Antineutrino Detector
Use reactor and detector simulations and a ‘fault-tree analysis’
to compare safeguards with and without the antineutrino detector
LLNL
Next Steps in the LLNL/SNL program
Complete quantitative comparison with existing IAEA safeguards
Solicit further input from Safeguards Agencies
Applied Antineutrino Physics Workshop September 25-26
at Lawrence Livermore National Laboratory, Livermore CA
(Link soon at www.llnl.gov/neutrinos)
Reduce detector footprint and increase sensitivity
Detector deployment is essential for demonstrating practical
utility: Deployment in a non-nuclear weapons state under
IAEA safeguards is the best way to demonstrate the
effectiveness of this technology
LLNL