WATCHMAN Analysis
(Preliminary Results)
Using antineutrino detectors for nonproliferation
WATCHMAN project collaboration meeting
Blacksburg, Virginia – May 1, 2014
Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin
Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000. SAND NO. 2014-3627 C.
Applications of large antineutrino detectors
This analysis seeks to understand the usefulness of antineutrino
detectors for nonproliferation monitoring, particularly in
comparison to existing technologies
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Key features of antineutrino signal
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Produced in decay chain that follows nuclear fission
Highly penetrating and detectable at long ranges
Effectively impossible to falsify, disguise, or shield
Applications considered
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Detection of nuclear explosions (e.g., nuclear tests)
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Subject of prior study (Bernstein, West, and Gupta, 2001)
50 kT detector could sense 1 kT test within 10 km (3 MT ⇒100 km)
Monitoring nuclear reactors
Preliminary Results - 2
Reactor monitoring
“By 2016, demonstrate remote monitoring capabilities for reactor operations.”
-NNSA Strategic Plan (May 2011)
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Reactors play a key role in nonproliferation
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Plutonium is primarily produced in nuclear reactors when neutrons
are absorbed by uranium
A State seeking to develop a clandestine nuclear weapons program
might use plutonium from undeclared reactors
Reactor monitoring can support nonproliferation mission
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Providing assurances to international community that only declared
reactors are being operated (no undeclared reactors)
Revealing presence of undeclared reactors
Verifying declarations from a State regarding its reactor operations
Preliminary Results - 3
Using antineutrinos to monitor reactors
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Antineutrinos provide complementary information to
other safeguards
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Allow remote, persistent, nonintrusive monitoring
Provide direct information about conditions in the core
Antineutrinos can be used to determine
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Existence of reactor
Operational status of reactor (e.g., on/off)
Power level of reactor
Type/burn-up of reactor fuel
Location of reactor (?)
Increasing data
quality required
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Preliminary Results - 4
Reactor monitoring scenarios
Reactor Exclusion Zone
No Undeclared Reactors
Ensure that there are no
reactors operating in an area
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Simplest scenario
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Easiest to find reactors built after
detector installation
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Search for excess antineutrino
signal above background levels

Similar to previous case except…
 Requires understanding of
antineutrino signal from declared
reactors
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Might work for existing reactors
Potentially subject to
countermeasures
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Ensure that only declared
reactors are operating
State being monitored could build
declared reactor near detector
CM might be restrained by political
or economic factors

Build small detectors near each
declared reactor and/or model
based on safeguards declarations
Lower sensitivity due to higher
backgrounds from declared
reactors
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Might reduce impact of CM since
expected sensitivity is lower
Preliminary Results - 5
Reactor monitoring scenarios (cont.)
Verify Declarations
Verify that declarations about
reactor operations are accurate
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Verify operational status, power
level, and/or burn-up of fuel in one
or more reactors
Good signal quality required

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Good statistics / high count rate
May be difficult to monitor many
reactors with one detector
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Deconvolving signals adds extra
challenge
Employment Regimes
Standoff
Range
Detector
Size
Low
< 1 km
1 – 10 T
Medium
1 – 25 km
0.1 – 1 kT
High
25 – 1000 km
0.1 – 1 MT
Engagement with State being monitored
Cooperative
Allows installation and access
to detectors and data
Semicooperative
Allows installation of detectors
but limits access to detectors
and/or data
Noncooperative
Does not permit installation of
detectors
Preliminary Results - 6
Analysis of Use Cases
Suitability analysis
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Following slides address the suitability of antineutrino
detectors for different use cases
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“Are antineutrino detectors a good fit, based on technical and
operational considerations?”
Analysis does not yet address need for such capabilities
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Comparison to other technologies in progress
Analysis methodology
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Driven by expert feedback
Focused on mission suitability and need
Did not independently verify technical capabilities of
antineutrino detectors or project-management assumptions
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Information from project team regarding sensitivity, range, timeline,
size, budget, etc., was assumed to be correct
Preliminary Results - 8
Antineutrino detectors can support dual
missions
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Detectors can support nonproliferation and scientific research
Detectors may provide advantages to host country
 Access to world-class research facility
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Gives State an incentive to be monitored
May entice third-party State to allow cross-border monitoring
Potential for influx of foreign capital investment
Cost sharing with scientific organizations is possible
 State being monitored may be willing to pay for detectors to enhance
scientific capabilities
 Foreign states may contribute to join collaboration
Detectors provide focus for multinational scientific collaboration
 Provides a basis for interpersonal and organizational relationships that
could ease diplomatic tensions
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Preliminary Results - 9
Suitability of antineutrino detectors
Cooperative and
Semi-cooperative
Low
Standoff
Medium
Standoff
Non-cooperative
High
Standoff
Low
Standoff
Medium
Standoff
High
Standoff
Exclusion
Zone
No
Undeclared
Reactors
Reactor
Verification
Poor fit
Poor fit, but might have
niche applications
Moderately good fit,
but with caveats
Good fit
Preliminary Results - 10
Suitability of Antineutrino Detectors
Cooperative and
Semi-cooperative
Low
Standoff
Exclusion
Zone
No
Undeclared
Reactors
Reactor
Verification
Poor fit
Medium
Standoff
Non-cooperative
High
Standoff
Low
Standoff
Medium
Standoff
High
Standoff
• Access to site an important differentiator between use cases
• Cooperative and semi-cooperative rankings similar
• Non-cooperative cases create additional challenges
• Antineutrino detectors do offer advantages that my be
particularly helpful for semi-cooperative cases
• Remote monitoring capability permits non-intrusive
installation (e.g., off-site)
• Signal provides little information about other activities
Poor fit, but might have
niche applications
Moderately good fit,
but with caveats
Good fit
Preliminary Results - 11
Suitability of Antineutrino Detectors
Cooperative and
Semi-cooperative
Low
Standoff
Medium
Standoff
Non-cooperative
High
Standoff
Low
Standoff
Medium
Standoff
High
Standoff
Exclusion
Zone
No
Undeclared
Reactors
Reactor
Verification
Poor fit
• Antineutrino signal offers unique opportunities for detection of
undeclared reactors
• (Semi) cooperative use makes countermeasures unlikely
• Ratings assume country is willing to accept detector
Poor fit, but might have
niche applications
Moderately good fit,
but with caveats
Good fit
Preliminary Results - 12
Suitability of Antineutrino Detectors
Cooperative and
Semi-cooperative
Low
Standoff
Medium
Standoff
Non-cooperative
High
Standoff
Low
Standoff
Medium
Standoff
High
Standoff
Exclusion
Zone
No
Undeclared
Reactors
Reactor
Verification
Poor fit
• Similar advantages to cooperative exclusion zone
• Declared reactors lower sensitivity and necessitate models and/or
calibration detectors to separate their signals
Poor fit, but might have
niche applications
Moderately good fit,
but with caveats
Good fit
Preliminary Results - 13
Suitability of Antineutrino Detectors
Cooperative and
Semi-cooperative
Low
Standoff
Exclusion
Zone
No
Undeclared
Reactors
Medium
Standoff
Non-cooperative
High
Standoff
Low
Standoff
Medium
Standoff
High
Standoff
• Small, close detector (e.g., outside containment dome) provides
sufficient signal without intruding on reactor operations
• Larger detectors less favorable
• Increased cost with no clear benefits
• Increased likelihood of capturing signals from other reactors,
which complicates signal analysis
Reactor
Verification
Poor fit
Poor fit, but might have
niche applications
Moderately good fit,
but with caveats
Good fit
Preliminary Results - 14
Suitability of Antineutrino Detectors
Cooperative and
Semi-cooperative
Low
Standoff
Exclusion
Zone
No
Undeclared
Reactors
Reactor
Verification
Poor fit
Medium
Standoff
Non-cooperative
High
Standoff
Low
Standoff
Medium
Standoff
High
Standoff
• Non-cooperative case
presumably involves crossborder detection due to
size and complexity of
detector
• Seems implausible to have
area of interest within 1 km
• May be niche cases in which
10’s of km are sufficient
Poor fit, but might have
niche applications
Moderately good fit,
but with caveats
Good fit
Preliminary Results - 15
Suitability of Antineutrino Detectors
Cooperative and
Semi-cooperative
Low
Standoff
Exclusion
Zone
No
Undeclared
Reactors
Reactor
Verification
Poor fit
Medium
Standoff
Non-cooperative
High
Standoff
Low
Standoff
Medium
Standoff
High
Standoff
• Antineutrino signal offers unique opportunities for
detection of undeclared reactors
• This range is potentially sufficient to reach areas of
interest, even with cross-border placement
• There exists the potential for countermeasures that
would lower the detector’s sensitivity
• Declared reactors lower sensitivity and necessitate
use of models and/or calibration detectors to
separate their signals
Poor fit, but might have
niche applications
Moderately good fit,
but with caveats
Good fit
Preliminary Results - 16
Suitability of Antineutrino Detectors
Cooperative and
Semi-cooperative
Low
Standoff
Exclusion
Zone
No
Undeclared
Reactors
Reactor
Verification
Poor fit
Medium
Standoff
Non-cooperative
High
Standoff
Low
Standoff
Medium
Standoff
High
Standoff
• High-standoff, non-cooperative (cross-border)
monitoring possible, but far from ideal
• Potential for countermeasures
• Complex data analysis
• Potentially useful capability in certain cases
• Unique features of antineutrino signal might
provide data otherwise unattainable
• Specific placement of reactors might mitigate
analysis challenges
Poor fit, but might have
niche applications
Moderately good fit,
but with caveats
Good fit
Preliminary Results - 17
Suitability of Antineutrino Detectors
Cooperative and
Semi-cooperative
Low
Standoff
Medium
Standoff
Non-cooperative
High
Standoff
Low
Standoff
Medium
Standoff
High
Standoff
Exclusion
Zone
No
Undeclared
Reactors
Reactor
Verification
Poor fit
Poor fit, but might have
niche applications
Moderately good fit,
but with caveats
Good fit
Preliminary Results - 18
Case Studies
Case Study: North Korea
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Context
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De-facto weapons state with 3 known nuclear tests, 4th possibly imminent
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Primary acquisition pathway is reprocessing of spent fuel from Yongbyon reactor
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Enrichment program currently being expanded, makes LEU for reactors, possibly HEU
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Inspections and technologies cannot provide a system solution
Reactors
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Yongbyon Nuclear Complex
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5 MWe reactor (20-30 MWth), est. capacity 4-6 kg Pu/year
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25 MWe reactor (~80 MWth) under construction
Antineutrino detector deployment scenarios
1. Reactor monitoring at Yongbyon using low-standoff detector under future agreement
2. MT detector deployment in China as a science facility that monitors Yongbyon reactor
activity as a secondary benefit
Preliminary Results - 20
Reactor Monitoring at Yongbyon
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Assumes a future agreement permitting inspector re-entry into Yongbyon
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Ton-scale antineutrino detector could be used to monitor operational status of
5 MWe and 25 MWe reactors
kT-scale detector would be useful to monitor complex
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There may be risk associated with investments in NK
Detailed analysis of detector at Yongbyon by Christensen, Huber, and Jaffke*
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Key benefit is recovering from loss of continuity of knowledge
1989 unloading of 5 MWe – deliberate steps to obfuscate fuel rod positions
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Operators declared spent fuel rods were reloaded into reactor
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Apart from costly fuel rod isolation and assays no way to confirm
If antineutrino monitors were in place, they could detect the difference in fuel
burnup of fresh vs. spent fuel
* “Antineutrino reactor safeguards – a case study,” E. Christensen, P. Huber, P. Jaffke, arXiv:1312.1959 (2013).
Preliminary Results - 21
MT Detector in China
Country
N. Korea
S. Korea
China
Japan
Total BG
Incl. Under Construction*
Capacity (GWth) Signal (ev/year/MT)
0.11
2,287
78.5
44,917
133.4
40,629
138.9
21,741
350.8
107,287
350
Detection Time to 3σ
[days]
100 km
Detector primarily a scientific facility
• Engage China in intl. “big-science” collaboration
• Chinese already invested in Daya Bay experiment
Secondary benefit of monitoring activity at Yongbyon
Complex
• Large background signal from regional nuclear reactors
300
1 MT
250
5 MT
200
150
100
50
0
Assumptions
• 50% efficiency
• 100% reactor operation factor
• 4000 mwe – no other cosmogenic BG
• 3σ confidence
*IAEA Power Reactor Information System (PRIS) Database
0
50
100
Reactor Power [MWth]
1 MT
5 MWe
xxx
25 MWe
130 days
Both Reactors 70 days
150
5 MT
180 days
26 days
14 days
Preliminary Results - 22
Case Study: Iran
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Context
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Uncertainty in assessment of Iran’s nuclear intentions and capabilities
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Proper combination of diplomacy, sanctions, and military action controversial
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Nov. 2013 agreement provides potential diplomatic solution with intrusive inspections
Facilities
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Bushehr Power Reactor (1000 MWe)
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Upcoming: Darkhovin (360 MWe LWR) and Arak (40 MWe HWR)
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Additional 16 reactors planned over next 15 years
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Broad-based facilities covering fuel cycle except reprocessing
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Esfahan Nuclear Complex – 3 small research reactors
Antineutrino detector deployment scenarios
1. Real-time reactor monitoring at Bushehir, Arak, and other reactors
2. Confidence-building measures through deployment of a kT detector at Esfahan to provide
an exclusion zone
Preliminary Results - 23
Real-time remote monitoring of reactors
Benefits for detector deployment
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Reduce inspector burden to refocus on unannounced inspections
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Independent check on operator declarations
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Near real-time warning of unexpected events such as reactor shutdowns
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Provide fine-grained diplomatic options in a semi-cooperative scenario to limit
escalation
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Remote, unattended operation possible
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Limited information provided by antineutrino detectors may be more acceptable to State
being monitored
Preliminary Results - 24
Confidence-building measures:
Esfahan exclusion zone
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Esfahan Nuclear Complex
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24 km2, operated by Atomic Energy Org. Iran (AEOI)
Center of expertise for conversion, fuel fabrication,
reactor operations, reactor R&D, ~ 3000 scientists
Tunnel complex – discovered 12/2004, violation of
IAEA safeguards, possibly 30-500 mwe
Deployment scenario and potential benefits
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40 kT detector in tunnel complex would monitor site
for hidden reactors
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Excludes 10 MW reactor from 2 km radius in 2 months @ 30 mwe, 5 km for 500 mwe
Continuous international presence in tunnels reduces likelihood of covert
activity
Engage Iranian scientists in large-scale scientific collaborations using detector
Counterarguments
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Scientific cost/benefit ratio needs to be weighed against other instruments and
collaboration
Preliminary Results - 25
Summary
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When used for nonproliferation purposes, antineutrino detectors…
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Antineutrino detectors are potentially well-suited to a variety of
cooperative monitoring situations
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Offer a uniquely robust signal that allows remote, persistent monitoring
Permit non-intrusive monitoring that directly probes core
Can support both scientific and nonproliferation missions
Providing verification of international agreements
Unclear if need exists (gap analysis in progress)
Opportunities for non-cooperative use are limited
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Areas of interest unlikely to be within range of low- and medium-standoff
detectors (T to kT)
High-standoff detectors (MT) potentially useful for revealing undeclared reactors
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Subject to countermeasures
Long range may increase backgrounds and complicate analysis
May be specific cases where these challenges can be addressed and detectors
could provide valuable data (e.g., cross-border monitoring of Yongbyon)
Preliminary Results - 26