Neutrinos and Nuclear Non-Proliferation August 12, 2019 Bryce - - PowerPoint PPT Presentation

Neutrinos and Nuclear Non-Proliferation

Bryce Littlejohn

Illinois Institute of Technology

August 12, 2019

Trinity: Alamagordo, New Mexico, USA

Trinity: Alamagordo, NM, USA, 1945 22kT TNT, 239Pu implosion device

Shock wave: 16 ms post-detonation

Trinity: Alamagordo, New Mexico, USA

Genbaku (A-Bomb) Dome, Hiroshima Peace Memorial Park

Hiroshima and Nagasaki, Japan, 1945

• Over 100,000 men, women and children lost 


their lives in the first nuclear attack at Hiroshima

• Over 50,000 lost in the subsequent Nagasaki attack

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Hiroshima Peace
 Memorial Park Remembrance Hall, Nagasaki

Hiroshima and Nagasaki, Japan, 1945

• Over 100,000 men, women and children lost 


their lives in the first nuclear attack at Hiroshima

• 235U gun design: 15kT
• Over 50,000 lost in the subsequent Nagasaki attack
• 239Pu implosion device similar to Trinity: 20kT

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Hiroshima Peace
 Memorial Park Genbaku (A-Bomb) Dome, Hiroshima Peace Memorial Park Remembrance Hall, Nagasaki

Tsar Bomba: Severny Island, Russia, 1961

• 50 MT multi-stage thermonuclear (fusion) device
• 10x more energetic than all explosives used in World War II
• 1500x more powerful than Hiroshima/Nagasaki a-bombs
• Total destruction radius (red) compared to Paris (yellow)

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Punggye-ri, North Korea, 2017

• Underground explosion estimated at 70-280 kT
• At least >4x more powerful than Hiroshima device
• Thought to be a fusion-boosted fission device
• Most recent of 6


North Korean
 device tests

• Some successfully tested


devices are rocket-mountable

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Nuclear Stockpiles

• We know that a single nuclear weapon is capable of causing a

humanitarian catastrophe

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The Point of All That

• Nuclear non-proliferation is more than an academic exercise
• Lives have been lost or changed forever from use of nuclear

weapons; lives currently are at risk.

• Fundamental science permits


functional nuclear weapons

• Can science also help to


control/monitor them?

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Peace Bell, Hiroshima Peace Park Hibakusha: Hiroshima and Nagasaki survivors

Nuclear Explosion Concepts

• Neutron-induced fission chain reactions
• Absolutely essential ingredients: 235U or 239Pu
• Nearby neutron likely to cause fission and release >1 neutron as a product
• These isotopes aren’t found in enriched form in nature

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Nuclear Control

• To control nuclear weapons, control/catalog 235U and 239Pu
• Control/monitor reactor operation = 239Pu control/monitoring
• ALL reactors make 239Pu;


some better than others

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• Reactor νe: made in beta-decay of 239Pu, 235U fission products
• Each isotope: different branches, so different neutrino energies (slightly)

Reactor Antineutrino Production

Antineutrino Energy (MeV) neutrinos/fission

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(Pu, U) Nucleus fission product beta, nuebar

reactor core

…

fission product beta, nuebar stable isotope

fission isotopes fission products νe-producing
 beta decays Table of the Isotopes

Reactor Antineutrino Detection

• Detect inverse beta decay with liquid or solid scintillator, PMTs
• IBD e+ is direct proxy for antineutrino energy

13 Energy (MeV) Daya Bay Monte Carlo Data

Prompt e+
 spectrum Delayed n-cap spectrum

Energy (MeV)

~30us capture time

Example: Daya Bay Detector

nGd nH

Neutrino Energy (MeV) Nuebar/Fission IBD X-section (x10-42)

• Fissions make both neutrinos AND energy
• More power made = more neutrinos released
• An IBD-based ex-situ reactor power monitor
• Achieved already in numerous reactor experiments up to >km distances

Reactor Power Monitoring

14 Daya Bay, Chin. Phys. C 41(1) (2017)

A reactor turned off. It turned back on.

• Fissions make both neutrinos AND energy
• More power made = more neutrinos released
• An IBD-based ex-situ reactor power monitor
• Know power without any in-core instruments (good for sodium reactors)
• Discover reactor or monitor operational status very far away (50+ km)
• None have been explicitly implemented as monitoring sub-systems

Reactor Power Monitoring

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• We know 239Pu makes fewer neutrinos than 235U
• Change in IBD/day is a direct measure of kg of 239Pu bred into fuel
• Numerous IBD experiments have seen reduction in IBD/day over fuel cycle
• Drawback: degeneracy between power and 239Pu content

Rate-Based 239Pu Monitoring

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Isotope

IBD/fission (x10-43)

238U

10.1

235U

6.7

241Pu

6.0

239Pu

4.4

Huber-Mueller
 Model

SONGS, nucl-ex[0808.0698]

• We know 239Pu makes lower energy neutrinos than 235U
• IBD prompt energy is a direct measure of kg of 239Pu bred into fuel
• Daya Bay has observed this change in spectrum
• Power (IBD rate) and 239Pu (IBD energy) can be independently monitored

Energy-Based 239Pu Monitoring

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Antineutrino Energy (MeV) neutrinos/fission

Christensen, Huber, Jaffke, ins-det[1403.7065]

QUESTIONS?

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