Future nuclear weapon policies James M. Acton jacton@ceip

Future nuclear weapon policies

James M. Actonjacton@ceip.org

(Some) elements of nuclear posture

• Force size and structure• Deployed and reserve systems; readiness status

• Military Organization• Troops; training; procedures; operations

• Enabling systems• Command and control; early warning; ISR; targeting

• Infrastructure• Warhead production/maintenance facilities; industrial base; test facilities

• Declaratory policy• Statements; training and exercises; domestic discourse

• War plans• Treaty obligations

Questions raised by reductions

• Can U.S. fulfill “deterrence” requirements?• Will weapons reach target?

• Reliability; pre- and post-launch survivability • Will weapons destroy target?

• Yield, accuracy and target location error• Can requirements be revised?• How will allies/adversaries view U.S. resolve and capability?• What will the effects on “strategic stability” be?• …

Current U.S. force structure

Platform Missile Warhead

ICBM (Silo based) Minuteman III W78; W87

SLBM Ohio-class SSBN Trident-D5 W76-0/1; W88

Heavy Bombers B-2 (Gravity bombs) B61-7/11; B83-1

B-52H ALCM W80-1(+ gravity bombs)

“Tactical” fighters F-15E; F-16C/D (Gravity bombs) B61-3/4/10

Future of the triad

• Political context crucial; in practice force structure will be determined by politics of the moment as much as nuclear strategy• ICBM replacement will probably be delayed further (beyond

2020); early abandonment very unlikely (jobs!)• Very strong support for SLBMs• Multiple decision points related to heavy bombers and tactical

fighters coming up• Air leg most vulnerable

Arguments for heavy bombers and tactical fighters

• Unique ability to hold buried targets at risk• But, how much do these targets really matter?

• Stealth as alternative to speed for defense penetration• But, how likely is effective BMD?

• Recallable• But, how many war plan options include only aircraft?

• Forward deployment as tool for assurance• But, are there alternatives?

• Signaling as tool for crisis management

A growing role for conventional weapons in strategic war plans?

DoD is directed to conduct deliberate planning for non-nuclear strike options to assess what objectives and effects could be achieved through integrated non-nuclear strike options, and to propose possible means to make these objectives and effects achievable. Although they are not a substitute for nuclear weapons, planning for non-nuclear strike options is a central part of reducing the role of nuclear weapons.

Report on Nuclear Employment Strategy of the United States (2013)

• Probably not about large-scale replacement.

Types of target in a “counterforce” attack against North Korea

• Fixed, soft targets• ICBM sitting on a launch pad

• Fixed, buried targets• Warhead storage facilities; leadership; command and control• Probably tens, potentially hundreds of metres deep

• Mobile, soft targets• Road-mobile missiles

Massive ordnance penetrator

• Total mass: 13,600 kg• HE mass: 2,400 kg• Can reportedly

penetrate to 20 m in reinforced concrete (much less than nuclear weapons)

Physics of conventional penetrators

• From Nelson (2002)

Young Penetration Equation (SI Units)

D: Depth S: Penetrability of targetN: Nose performance coefficientm: Mass A: Cross sectional areaV: Speed

CPGS technological approaches

Comparison of penetrator effectiveness

• Ratio of penetration depths: 1.3-2.1• CPGS penetrator would only contain about 10% of

the HE that MOP does.

MOP CPGS

V (m/s) 500 [?] 1,000-1,200

m/A (kg/m) 27,000 14,000-21,000

Mobile missile hunting

• Need to locate and track missiles• If using standoff weapons need to provide inflight target updates

(or risk waiting until they’re stationary)• North Korea has hundreds of mobile ballistic missiles

• Only a small fraction might contain a nuclear warhead, but very hard to tell which is which

• 1991 Gulf War: 1,460 sorties; 0 confirmed kills• 2006 Israel-Hizbollah war: 80-90% of Hizbollah’s medium- and long-

range rocket launchers destroyed. But, took time and relied on attacking launchers after missiles has fired.

Nuclear v. conventional options

• Lethal radius from flechette weapon: <100 m, possibly much less (my calculation)• TEL can traverse this distance in 10 s

• Lethal radius from 100 kT nuclear weapon: 2,900 m (McKinzie et al. 2001)• TEL can traverse this distance in 260 s

• Hunting mobile missiles with conventional weapons much harder than nuclear weapons