Neutrinos and Nuclear Non-Proliferation August 12, 2019 Bryce Littlejohn Illinois Institute of Technology
Trinity: Alamagordo, NM, USA, 1945 Trinity: Alamagordo, New Mexico, USA 22kT TNT, 239 Pu implosion device Shock wave: 16 ms post-detonation
Trinity: Alamagordo, New Mexico, USA
Hiroshima and Nagasaki, Japan, 1945 Remembrance Hall, Nagasaki • 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 Genbaku (A-Bomb) Dome, Hiroshima Peace Memorial Park Hiroshima Peace Memorial Park 4
Hiroshima and Nagasaki, Japan, 1945 Remembrance Hall, Nagasaki • Over 100,000 men, women and children lost their lives in the first nuclear attack at Hiroshima • 235 U gun design: 15kT • Over 50,000 lost in the subsequent Nagasaki attack • 239 Pu implosion device similar to Trinity: 20kT Genbaku (A-Bomb) Dome, Hiroshima Peace Memorial Park Hiroshima Peace Memorial Park 5
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) 6
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 7
Nuclear Stockpiles • We know that a single nuclear weapon is capable of causing a humanitarian catastrophe 8
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? Peace Bell, Hiroshima Peace Park Hibakusha: Hiroshima and Nagasaki survivors 9
Nuclear Explosion Concepts • Neutron-induced fission chain reactions • Absolutely essential ingredients: 235 U or 239 Pu • Nearby neutron likely to cause fission and release >1 neutron as a product • These isotopes aren’t found in enriched form in nature 10
Nuclear Control • To control nuclear weapons, control/catalog 235 U and 239 Pu • Control/monitor reactor operation = 239 Pu control/monitoring • ALL reactors make 239 Pu; some better than others 11
Reactor Antineutrino Production • Reactor ν e : made in beta-decay of 239 Pu, 235 U fission products • Each isotope: different branches, so different neutrino energies (slightly) Table of the Isotopes (Pu, U) Nucleus fission product fission product stable isotope … fission isotopes beta, nuebar beta, nuebar reactor core fission products neutrinos/fission ν e -producing beta decays Antineutrino Energy (MeV) 12
Reactor Antineutrino Detection • Detect inverse beta decay with liquid or solid scintillator, PMTs • IBD e+ is direct proxy for antineutrino energy Prompt e + spectrum Energy (MeV) ~30us capture time IBD X-section (x10 -42 ) Nuebar/Fission Delayed n-cap spectrum nGd nH Neutrino Energy (MeV) Energy (MeV) Daya Bay Monte Carlo Data Example: Daya Bay Detector 13
Reactor Power Monitoring • 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 It turned back on. A reactor turned off. Daya Bay, Chin. Phys. C 41(1) (2017) 14
Reactor Power Monitoring • 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 15
Rate-Based 239 Pu Monitoring • We know 239 Pu makes fewer neutrinos than 235 U • Change in IBD/day is a direct measure of kg of 239 Pu bred into fuel • Numerous IBD experiments have seen reduction in IBD/day over fuel cycle • Drawback: degeneracy between power and 239 Pu content SONGS, nucl-ex[0808.0698] 238 U IBD/fission (x10 -43 ) Huber-Mueller 10.1 Model 235 U 241 Pu 6.7 6.0 239 Pu 4.4 Isotope 16
Energy-Based 239 Pu Monitoring • We know 239 Pu makes lower energy neutrinos than 235 U • IBD prompt energy is a direct measure of kg of 239 Pu bred into fuel • Daya Bay has observed this change in spectrum • Power (IBD rate) and 239 Pu (IBD energy) can be independently monitored Christensen, Huber, Jaffke, ins-det[1403.7065] neutrinos/fission Antineutrino Energy (MeV) 17
QUESTIONS? 18
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