[PPT] - AIT-WATCHMAN A Remote Reactor Monitor and Advanced Instrumentation PowerPoint Presentation

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AIT-WATCHMAN

A Remote Reactor Monitor and Advanced Instrumentation Testbed

Christopher Grant

On behalf of the WATCHMAN Collaboration

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The link between nuclear reactors and nuclear weapons

September 11, 2019 TAUP 2019 - Toyama, Japan 1

!

235U 85Kr 141Ba Energy

! ! !

235U 235U

A source of fissionable material, such as 235U, is required to manufacture nuclear weapons However, 235U is not ideal due to its rare isotopic abundance (0.7%) and the challenge of achieving over 90% enrichment needed for a weapon

SLIDE 3

September 11, 2019 TAUP 2019 - Toyama, Japan 2

The link between nuclear reactors and nuclear weapons

!

238U

An alternative method, and one that was used by many countries, involves the production of 239Pu via the transmutation of natural Uranium inside a nuclear reactor

239U

"

#/%~ 23 min

' ()

239Np

"

#/%~ 2.4 days

239Pu

"

#/%~ 24,000 years

' () ̅ + ̅ + Plutonium can be easily separated from Uranium with chemistry

SLIDE 4

Reactors are operating all over the world

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S. M. Usman, G. R. Jocher, S. T. Dye, W. F. McDonough, and J. G. Learned, Scientific Reports 5, Article number: 13945 (2015)

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Non-Proliferation Treaty (NPT) – an attempt to mitigate the risk

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Nuclear Weapon State Ratifiers Nuclear Weapon State Acceders Other Ratifiers Other Acceders or Succeeders Withdrawn Non-signatory Unrecognized State, abiding by acceders

These agreements are supported by physical measurements and monitoring systems overseen the International Atomic Energy Agency (IAEA) and the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO)

SLIDE 6

Can neutrinos be used to monitor distant reactors?

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Roughly 6 ̅ "# released per fission and ~1021 fissions per second in a typical 3 GWt power reactor, means that you have ~1022 ̅ "# per second isotropic emission

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Can neutrinos be used to monitor distant reactors?

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25 km stand-off

Water Cherenkov Detector

Inverse Beta Decay (IBD):

̅ "# + % → '( + )

Roughly 6 ̅ "# released per fission and ~1021 fissions per second in a typical 3 GWt power reactor, means that you have ~1022 ̅ "# per second isotropic emission

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Can neutrinos be used to monitor distant reactors?

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25 km stand-off

! " ~ 10&'( cm( "+

(

Water Cherenkov Detector

Inverse Beta Decay (IBD):

̅

. + 0 → 23 + 4

Can expect “several” interactions per kiloton of water per day at 25 km distance Roughly 6 ̅

. released per fission and ~1021

fissions per second in a typical 3 GWt power reactor, means that you have ~1022 ̅

. per

second isotropic emission

SLIDE 9

Can neutrinos be used to monitor distant reactors?

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25 km stand-off

! " ~ 10&'( cm( "+

(

Water Cherenkov Detector

Inverse Beta Decay (IBD):

̅

. + 0 → 23 + 4

Can expect “several” interactions per kiloton of water per day at 25 km distance

Monitoring capability with antineutrinos studied in great detail in the following reference:

A. Bernstein, et al., Science & Global Security, 18:127–192, 2010

Roughly 6 ̅

. released per fission and ~1021

fissions per second in a typical 3 GWt power reactor, means that you have ~1022 ̅

. per

second isotropic emission

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AIT-WATCHMAN

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(Advanced Instrumentation Testbed – WATer CHerenkov Monitor of ANtineutrinos)

NNSA’s Office of Defense Nuclear Nonproliferation has funded WATCHMAN R&D since 2012. Mission need: demonstrate and evaluate the viability and scalability

f antineutrino-based technologies for remote reactor discovery and monitoring.

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AIT-WATCHMAN

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(Advanced Instrumentation Testbed – WATer CHerenkov Monitor of ANtineutrinos)

Primary Goals:

Confirm existence of an operating reactor (ie. determine unknown reactor is
perating in presence of another known reactor)
Determine power plant operational status with and without prior knowledge
Demonstrate Gd-loaded water as a scalable detector medium
Enable future technology upgrades:

Water-based liquid scintillator WbLS, Large-Area Picosecond Photodetectors (LAPPDs), techniques for Cherenkov and scintillation light separation, etc. NNSA’s Office of Defense Nuclear Nonproliferation has funded WATCHMAN R&D since 2012. Mission need: demonstrate and evaluate the viability and scalability

f antineutrino-based technologies for remote reactor discovery and monitoring.

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AIT-WATCHMAN

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Hartlepool Reactor AIT-WATCHMAN at Boulby Underground Lab

(Advanced Instrumentation Testbed – WATer CHerenkov Monitor of ANtineutrinos)

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AIT-WATCHMAN

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Hartlepool Reactor AIT-WATCHMAN at Boulby Underground Lab

25 km

(Advanced Instrumentation Testbed – WATer CHerenkov Monitor of ANtineutrinos)

Hartlepool Reactor has two cores, each operates at a power of 1.5 GWt for a total of just over 3 GWt

WATCHMAN

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Baseline WATCHMAN Detector Design

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Gd-doped (0.1%) water Cherenkov detector
~1 kiloton fiducial volume
~3600 high quantum efficiency, low radioactivity,

10” PMTs (~20% photocathode coverage)

Active outer veto
Multiple calibration system access ports and large

central access plug for future instrumentation Gd-loaded water was chosen because of it’s scalability over other media - it’s the most viable path to a 100 kt – 1 Mt scale detector

Cutaway view

~20 m ~20 m

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Advantages of gadolinium loading

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̅ "# $ %

Gd

& & &

Prompt signal Delayed signal (~8 MeV gamma cascade)

'(

Gd provides roughly 70% neutron detection efficiency in WATCHMAN

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Gd-loading demonstrator

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The Gd-loading and water purification system is based on EGADS (Evaluating Gadolinium’s Action on Detector Systems). This was built to test Super-K detector materials in contact with Gd-doped water. System is essentially lossless – it extracts Gd, purifies the water, and adds the Gd back in. Water transparency remained within the SK ultra-pure range for over two years.

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Backgrounds for reactor monitoring

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Gammas from radioactivity within detector materials or within the internal water volume Detector related backgrounds (random coincidences) γ γ In addition to antineutrinos from the Earth and from other nuclear reactors, the following backgrounds need to be addressed…

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Backgrounds for reactor monitoring

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Gammas from radioactivity within detector materials or within the internal water volume Detector related backgrounds (random coincidences) γ γ In addition to antineutrinos from the Earth and from other nuclear reactors, the following backgrounds need to be addressed… "

#

Fast neutrons from nearby rock muons "

9Li

Long-lived radionuclides produced by spallation (9Li and 8He) that undergo $-decay with neutron emission

#

Cosmogenic related backgrounds (correlated events)

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Background Measurements

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PRELIMINARY Multiplicity And Recoil Spectrometer (MARS)

Plastic scintillator + GdO2 (1%) 12 layer detectors Neutron converter

3,560 lbs of lead

in a steel table Neutron energy spectrum was measured by MARS at three different depths in Kimbleton Underground Research Facility (KURF). The data was compared with an existing model and other measurements.

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Background Measurements

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Neutron multiplicity 2 3 4 ]

1

Rate [day

2 −

10

1 −

10 1 10

Data FLUKA Geant4

PRELIMINARY

2-ton Gd-loaded water target surrounded by pure water veto

WATCHBOY Detector

Watchboy was deployed at the same depth as

MARS. FLUKA simulations of neutrons in

WATCHBOY, using the MARS measured neutron energy spectrum as input, agree with the data.

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Boulby Underground Laboratory

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Depth of 1.1 km (2805 mwe) Cleanliness in the underground lab will reduce the impact of dust and other environmental contamination This facility is well-established, hosting a variety of low- background particle physics experiments and other multidisciplinary projects

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Estimated sensitivity for the baseline design

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Component Events/week Core-1 4.2 Core-2 4.2 World reactors 1.5 Accidentals 0.9 Fast neutrons* 0.6 Radionuclides 0.1 Total 11.3

*Fast neutron sims with FLUKA still in progress

Summary of background budget WATCHMAN simulations use combination of customized rat-pac with BONSAI for event reconstruction

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Estimated sensitivity for the baseline design

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! (1) Observe any reactor ̅ ! signal over background?

25 km

unknown

~1 week of detector live time (95% C.L.)

Component Events/week Core-1 4.2 Core-2 4.2 World reactors 1.5 Accidentals 0.9 Fast neutrons* 0.6 Radionuclides 0.1 Total 11.3

*Fast neutron sims with FLUKA still in progress

Summary of background budget WATCHMAN simulations use combination of customized rat-pac with BONSAI for event reconstruction

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Estimated sensitivity for the baseline design

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! (1) Observe any reactor ̅ ! signal over background?

25 km

! (2) Observe the presence of another reactor?

25 km

!

unknown known unknown

~1 week of detector live time (95% C.L.) ~1 month of detector live time (95% C.L.)

Component Events/week Core-1 4.2 Core-2 4.2 World reactors 1.5 Accidentals 0.9 Fast neutrons* 0.6 Radionuclides 0.1 Total 11.3

*Fast neutron sims with FLUKA still in progress

WATCHMAN simulations use combination of customized rat-pac with BONSAI for event reconstruction Summary of background budget

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Estimated sensitivity for the baseline design

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! (1) Observe any reactor ̅ ! signal over background?

25 km

! (3) Observe ON/OFF transition of one reactor?

25 km

!

known known unknown

~1 week of detector live time (95% C.L.) ~10 months of detector live time (95% C.L.)

Component Events/week Core-1 4.2 Core-2 4.2 World reactors 1.5 Accidentals 0.9 Fast neutrons* 0.6 Radionuclides 0.1 Total 11.3

*Fast neutron sims with FLUKA still in progress

Summary of background budget WATCHMAN simulations use combination of customized rat-pac with BONSAI for event reconstruction ! (2) Observe the presence of another reactor?

25 km

!

unknown known

~1 month of detector live time (95% C.L.)

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Approximate Timeline for WATCHMAN

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2019 2020 2021 2022 2023 2024 2025

Design Phase Excavation AIT Installation Commission/Calibrate WATCHMAN

2026 2027

AIT Future

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Future R&D for the Advanced Instrumentation Testbed (AIT)

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We are actively pursuing technology that could be deployed in WATCHMAN to greatly enhance reactor monitoring and increase physics

potential. Improved calorimetry, particle ID,

and directionality are key interest. Water-based Liquid Scintillator (WbLS) Large Area Picosecond Photodetectors (LAPPDs) Dichroic Winston Cones (“Dichroicons”)

Courtesy of T. Kaptanoglu (U. Penn), DPF 2019

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Potential physics in current and future phases

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Baseline WATCHMAN will be a valuable trigger for supernova neutrinos, providing input to

SNEWS. Roughly 4,000 total

events are expected for a SN located 10,000 light years away.

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Potential physics in current and future phases

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Baseline WATCHMAN will be a valuable trigger for supernova neutrinos, providing input to

SNEWS. Roughly 4,000 total

events are expected for a SN located 10,000 light years away.

WATCHMAN

Could the addition of WbLS, with greatly improved energy resolution, yield interesting oscillation physics? Investigations are currently underway…

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AIT-WATCHMAN Collaboration

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20 Institutions and 96 Collaborators from the US and UK

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Backup

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