Nuclear Weapons: Sources of Strength or Vulnerability? Physics Dept. CCNY, 25 April 2017 Aron M. Bernstein Physics Dept., Lab For Nuclear Science MIT

Some say nuclear disarmament is utopian, premature, a dream. I say the illusion is that nuclear weapons provide security” UN Secretary-General Ban Ki-moon. Seoul, Oct. 2012

• current dangers, pathways to nuclear war? • nuclear weapons, Hiroshima, atomic scientists • force deployment; deterrence, war by accident? • NPT, Iran Agreement, N. Korea • maintenance/modernization • outlook- citizen education, participation

Why think about nuclear weapons?

• Not used since 1945 -Hiroshima and Nagasaki (nuclear taboo) • No danger since 1991-Soviet Union collapsed. • deterrence works (peace through strength) “If you want peace prepare for war” (Roman) • let's work on more important issues like climate change…. It is two and a half minutes to midnight

2017 Doomsday Clock Statement

Science and Security Board Bulletin of the Atomic Scientists

Editor, John Mecklin

Why think about nuclear weapons?

• Not used since 1945 -Hiroshima and Nagasaki (nuclear taboo) • No danger since 1991-Soviet Union collapsed. • deterrence works (peace through strength) “If you want peace prepare for war” (Roman) • let's work on more important issues like climate change….

dangers are increasing Bulletin of Atomic Scientists “Doomsday Clock” reset to Cold War era levels

IT IS TWO AND A HALF MINUTES TO MIDNIGHT©

cold war legacy: concepts, weapons, deployment modes • US, Russia have 900 weapons ready to fire tension increasing Ukraine, Crimea, Syria modernizing weapons, delivery systems arms race • proliferation: India, Pakistan, N. Korea Nuclear Weapons Education Initiative

participate in education, public discourse

• give a few lectures in undergraduate courses • could be part of a modern physics, science, history, politics,…course • give a focused course on nuclear weapons (preferably interdisciplinary) • objective, factual, discussion of the issues • this is not a call to politicize the classroom • it is a call for creativity and moral responsibility • informal network of interested faculty members/students • students can request courses/information from the faculty How do weapons work? Critical Mass ≈10kgm 235U, ≈ 6kgm 239Pu > 2 neutrons per fission Nuclear Weapons - basic technology concepts [UNC] 1/15/13 4:47 PM

escape and a chain reaction is not possible; such a mass is termed subcritical. If the neutrons generated exactly equal the number consumed in subsequent fissions, the mass is said to be critical. If the mass is in excess of this, it is termed supercritical.

Fission (atomic) weapons are simply based on assembling a supercritical mass of fissile material quickly enough to counter disassembly forces.

The majority of the energy release is nearly instantaneous, the mean time from neutron release to fission can be of the order of 10 nanoseconds, and the chain reaction builds exponentially. The result is that greater than 99% of the very considerable energy released in an atomic explosion is generated in the last few (typically 4-5) generations of fission -- less than a tenth of a microsecond.*

This tremendous energy release in a small space over fantastically short periods of time creates some unusual phenomena -- physical conditions that have no Nuclear Weaponsequal on earth, Physics: no matter orderhow much of TNTmagnitude is stacked up. estimate 235 239 Plutoniumfissionable (239Pu) ismaterial the principal fissileU, materialPu used in today's nuclear completelyweapons. The fission actual amount1 kgm of -> this 20kTon fissile material explosion required for a nuclear weapon is shockingly small. blast lasts ~ 1 u sec Below is a scale model of the amount of 239Pu required in a weapon with the force thattemperature destroyed the city> interior of Nagasaki of sun in 1945:

critical mass 15 Kgm (U) , 5Kgm (Pu)

In the Fat Man (Nagasaki) weapon design an excess of Pu was provided. Most of the remaining bulk of the weapon was comprised of two concentric shells of high explosives. Each of these was carefully fashioned from two types of explosives with differing burn rates. These, when detonated symmetrically on the outermost layer, caused an implosion or inward-moving explosion.

The two explosive types were shaped to create a roughly spherical convergent shockwave which, when it reached the Pu 'pit' in the center of the device, caused it to collapse.

The Pu pit became denser, underwent a phase change, and became supercritical.

A small neutron source, the initiator, placed in the very center of this Pu pit, provided an initial burst of neutrons -- final generations of which, less than a

http://simplethinking.com/home/nuclear_weapons.htm Page 2 of 8 Hiroshima Aug. 6, 1945 15kTons ~ 2% efficient ≈35% killed, ½ first day, blast, burns, radiation Modern bombs are ≥ 10 times more powerful high altitude bomb-EMP could destroy all US electronics one bomb, one city, many bombs - nuclear winter

We Meant so Well

I.I. Rabi at Los Alamos on the 40th anniversary of Trinity

• First we were afraid that Hitler would get the bomb

• Then we were afraid that we would get it

Debate: Utility of Nuclear Weapons

Pro Con • not necessary; were • Ended war in Japan the first step in the • Saved casualties in cold war WW2 • Needlessly killed • Prevented (deterred) Japanese civilians WW3 US/USSR • European war was not likely without nuclear weapons Expectations about the bomb: 1945 • Atomic Scientists(Oppenheimer,Bohr,Franck, Szilard) so terrifying that war could be ended • genocidal weapons • common problem that mankind should solve together no secret, no monopoly, no defense international control required One World or None • Politicians (Churchill, Roosevelt, Stalin,..) a powerful tool to influence (coerce) others

Expectations about the bomb: 1945 • Atomic Scientists(Oppenheimer,Bohr,Franck, Szilard) so terrifying that war could be ended • common problem that mankind should solve together no secret, no monopoly, no defense international control required One World or None • Politicians (Churchill, Roosevelt, Stalin,..) a powerful tool to influence (coerce) others

neither was fully correct • small coercive influence during US monopoly (45-49) USSR took over Poland, Czechoslovakia China entered the Korean War • after NPT (1970) deterrence, abhorrence ⇒ non-use (nuclear taboo)

number of warheads cold war N. Korea ~5-10 Do we need to improve our nuclear arsenal?

US Trident II Submarine • 24 missiles x 4 = 96 warheads • could destroy that many targets • warheads;100kT, 475kT (Hiroshima ~15kT) • delivery time 15-30 min • total explosive power > 10MT • total allied bombing in WWII ~ 3 MT • could cause worldwide nuclear cooling, famine

• US 14 subs, England 4 (12+2 at sea) Can Nuclear War Happen?

not rationally- no country wants it but tense situations can get out of control

remainder of talk will focus on this Launch on Warning: accidental nuclear war?

• US and Russia have ~ 900 missiles on alert status • delivery times ~15 (30) min SLBM (ICBM) based • decision times ~ 10 min • first strike capability • false alarm (cyber?) -> mutual destruction global nuclear winter for ~ decade • US president has nuclear black box 24-7 • probability of error not negligible (complex systems) • each side vulnerable to the other’s system • Russian early warning system less robust • need public education, pressure to change Other Possible Pathways to Nuclear War

• escalation of a conventional war • Pakistan and India have ~ 100 weapons worldwide nuclear winter for several years.

• North Korea 5 nuclear weapons tests, developing delivery missiles threatens to use them- could get out of control

• complacency: nuclear weapons will never be used” no urgency to solve problem Luck has saved us on many occasions

• 1962 Cuban Missile Crisis -Soviet nuclear submarine commander did not fire his nuclear weapons. • US false alarm Nov. 1979 warning of 200 Soviet missiles on their way • 1983 a false alarm in the Soviet early warning system indicated a US missile attack; Soviet officer on duty did not report this to his superiors, preventing a nuclear war; similar incident on US side 1983-L. Perroots • many incidents-nuclear weapons dropped by accident-did not detonate (Schlosser- Command and Control) • hacking of early warning system?

• do nuclear weapons provide security or endanger it?

Nuclear Weapons Maintenance • Last US test 1992 ( No. 1132) • 1994 Science Based Los Alamos Stockpile Stewardship maintains weapons without exploding them: experiments test components, supercomputers model weapons • enhanced safety, reliability • Life extension, annual assessment

Modernization [arms race-decreased security?]

• 30 to 50 year plans to modernize all strategic delivery systems • new Start level-although Pentagon certified 1/3 reduction OK • cost ~ $18b/y 2021 to 2035 in FY 2016 dollars, increase of ~ 3% to 7% of military budget • total cost of ~ $1T over the next 30 years ($90 million/day) • improved accuracy: B61-12 bomb (bombers), improved fuzing Initiation of nuclear war

“Nuclear Button” National Security State • set up 1947; cold war, • atom bomb required quick action

• daily presidential security briefing nuclear briefcase Obama participated, not Trump

• effect on president’s policy? Nuclear Non-Proliferation Treaty (NPT) 1970 • 189 countries • P5 :US, Russia, China, England, France committed to disarm; no time schedule: article 6 • resolution to ban nuclear weapons-UN • Iran: 2015 agreement • outside treaty: India, Pakistan, Israel • N.Korea: joined, withdrew: 5 tests

N. Korea serious problem, not a crisis permanent war footing, spends ~25% of GNP on military army 1.1 Million ~ 15%

Seoul -1.1 million people -35 miles from N. Korea- ~13,000 artillery there Korean war 1950-53 armistice, no peace treaty

5 nuclear weapons tests • first (2009) ~0.5kT detected international monitoring stations • 2 in 2016 • accelerated ballistic missiles program (26 in 2016). • violation of UN Security Council resolutions.

Obama policy “strategic patience”- sanctions waited for N. Korea to change course did not work-sanctions evaded, capabilities increasing

Trump policy: get China to solve problem, threaten force direct diplomacy needed: carrots and sticks start with freeze

negotiations with N. Korea Zigs and Zags

N. Korea signs NPT 1985. safeguards started in 1992 serious problems emerged with IAEA Agreed framework 1994- 2002; N.Korea shut down its reactor, to be replaced mutual accusations of not carrying it out Jan. 2003: N. Korea withdraws from NPT first bomb test 2006 ≈ 0.5 kT (fizzle?)- detected CTBT0 negotiations in 2008, 9 didn’t succeed

US regarded agreement as freezing weapons development, N. Korea wanted diplomatic recognition, normalization and aid

N.Korea background information China does not want a failed nuclear weapons state on their border 90% of the trade that North Korea has is with China US THAAD (Terminal High Altitude Area Defense) missile deployment- problem with China

N. Korea made recent overtures-ignored

“Reckless Leader Nuclear Strategy Theory” (Thomas Schelling) leader cannot be counted on not to initiate nuclear war

Nixon-Kissinger tried this to end Vietnam War secret operation Giant Lance, Oct. 10, 1969- placed U.S. nuclear assets on high alert bomber squadron with nuclear weapons flew patterns near USSR. didn’t work and was terminated

What happens when 2 leader try the same tactic?? Kim Jong-un has been threatening to use nuclear weapons for years Trump – deterrence through threats “all options are on the table” weapons-grade plutonium, for possible military dimensions. For 10 15 years, and it does not intend to Capping Iran’s LEU years, if Iran violates the agreement, do so thereafter. Stockpile UN sanctions will snap back into place 8,000 kg and the United States and the inter- Intrusive Monitoring national community will have the The agreement will put in place time necessary to respond. Though enhanced international monitoring 6,000 the UN Security Council’s previous and accountancy to promptly detect prohibition on nuclear- capable missile and deter Iranian noncompliance. work will end after eight years, mis- The agreement will set up a multi- 4,000 siles without nuclear warheads are a layered system to monitor and significantly lesser threat. inspect every aspect of Iran’s nuclear supply chain and fuel cycle, 2,000 No Deal, No Limits including continuous monitoring The final P5+1 agreement with Iran at some sites for 20–25 years. Other should not be judged on how it ad- elements, including access to a wider 0 dresses any single element of Iran’s Nov. Nov. Nov. June 10 Years number of nuclear sites—notably 2012 2013 2014 2015 nuclear program. Instead, policy- centrifuge manufacturing sites—and makers should assess its overall inspections on short notice under the Source: JCPOA impact on reducing Iran’s nuclear terms of Iran’s additional protocol, capacity and improving international will be permanent. Inspectors will Incentives for Iranian monitoring and verification. have access to any site, anywhere, Follow-Through There is no better deal on the including military sites, if there The structure of the nuclear deal gives horizon. is evidence of suspicious nuclear Iran incentives to follow through on Congressional efforts to block activities. A special adjudication its commitments. No sanctions relief implementation would unravel the commission will ensure disputes will be granted until Iran has taken deal, undermine global support for are settled within 24 days; this steps to limit its uranium-enrichment the existing sanctions architecture, will ensure prompt access when program, convert the Arak heavy- and allow Iran to accelerate its nuclear necessary. With sufficient resources, water reactor, provide required trans- program and escape more-intrusive in- the International Atomic Energy parency, and give the IAEA the infor- ternational monitoring. The risk of an Agency will be able to verify Iran’s mation needed to resolve questions Iranian nuclear weapon and a military commitments effectively. about about past activities with conflict over the issue would grow. Key Restrictions Will Last Well Over a Decade Iran Agreement(2015)

Implementation of additional protocol, commitment not to reprocess plutonium, NPT obligations

Continuous surveillance of uranium mines and mills

Continuous surveillance of centrifuge production areas

LEU stockpile capped at 300 kg, no enrichment at Fordow, no new heavy-water reactors ~1/2 bomb

Limit of 5,060 IR-1 operating centrifuges extends breakout time to > 1y Very limited R&D on advanced centrifuges

Implementation begins 5 years 10 years 15 years 20 years 25 years

•The blocks Arms Control239Pu path to bomb (need ≈ 4Kgm ) Association is an independent, membership-based organization dedicated to providing authoriative information and practical policy solutions to address the dangers posed by the world’s most dangerous weapons. For more information, unfinished Arak reactor reconfigured: 6 Kgm Pu/y -> 1 Kgm/y visit www.armscontrol.org. no weapons-grade plutonium, ship all spent fuel (Permanent) • no addional heavy water reactors, will not reprocess fuel-15 years.

• but US polics prevenng taking full advantage of this opportunity Obama’s Nuclear Weapons Legacy?

• April 2009 Prague speech –abolish nuclear weapons • New Start Treaty (Feb. 2011)-agreed to modernize arsenal • improved Nuclear Security (Summits) • tried to engage Russia in further steps (failed) • Iran agreement (2015) • ~1000 nuclear weapons still on launch on warning (US, Russia) • N. Korea • did not declare a no first use policy • did not get the CTBT(Comprehensive Test Ban Treaty) ratified

Outlook; some reasons for guarded optimism

• no nuclear war since 1945 deterrence, nuclear taboo, luck • despite strains, NPT working reasonably well • CTBO in operation: detected ~0.5kT N.Korean test • budget constraints in Russia and US may lead to nuclear force reductions • world wide discussion of zero nuclear weapons • humanitarian renunciation of nuclear weapons (UN general assembly) • public education, opinion counts! Plenty of Work to Reduce Danger of Nuclear War

• take weapons off hair trigger alert • Iran agreement -follow through, don’t scrap it! • N. Korea-negotiations, not threats, involve China • US-Russia-reduce weapons to ~1000 including tactical, • stockpile stewardship program (maintain, not modernize) • use budget constraints to improve nuclear weapons policy • make NPT more effective prod US-Russia for reduction timetable • US discretionary budget > 50% military

• scientists/academics: nuclear weapons education • we need help with education project

discretionary_spending_pie,_2015_enacted.png 1,003×915 pixels 11/29/16, 3:25 PM

~ $600 Billion > next 7 countries

https://media.nationalpriorities.org/uploads/discretionary_spending_pie%2C_2015_enacted.png Page 1 of 1 Will Trump rip up the Iran agreement as he promised during the election campaign? “the stupidest deal of all time”

It is not just a US-Iran agreement the rest of the P5+ 1 want to keep it they are lifting sanctions and doing business

James Mattis, nominee for defense secretary NYT, Dec. 2 ”Despite his tough stance on Iran.. he thinks that tearing up the agreement is favors keeping the agreement would hurt the US and favors working with allies to enforce it’s terms”.

Bulletin of the Atomic Scientists

!(2.5min) 2017