The physical principles of thermonuclear explosives, inertial confinement fusion, and the quest for

236 Pages·2010·3.74 MB·English

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This document is the electronic version of the third printing (October 2002) of
theseventhcorrectedandexpandededitionofareportfirstdistributedatthe1997
INESAPConference, Shanghai, China, September8–10,1997.
ThesecondeditionofthisreportwastranslatedinRussianin1998bytheRussian
Foreignministryin Moscow.
Some minor modifications were made in order to achieve a proper linking of the
figures, which could not be modified so that a double numbering scheme had to
beused.
Afewpapers,Refs.[591]to[596],whichappearedafter2002areappendedtothe
bibliographyas additionalreferences.
iii
To TheodoreB. Taylor
and MarekThee
iv
Executive summary
This report is an assessment of the prospect of developing new (i.e., fourth gen-
eration) nuclear weapons in the context of the Comprehensive Nuclear Test-Ban
Treaty(CTBT)thatwasadoptedbytheUNGeneral Assemblyin1996andofthe
current moratoriumon nucleartestingineffect in allnuclear-weapon States.
The first chapter is a primer on thermonuclear weapons based on a scientific
understanding of the physical principles of existing nuclear weapons and on the
results of ISRINEX, a simple thermonuclear explosion simulation program spe-
cially developed for independent disarmament experts. Using this insight, it is
shownthattheconstructionofhydrogenbombsisinfactmuchlessdifficultthanis
generally assumed. Using present-day nuclear and computer technology, almost
anymodernindustrialcountrycould,inprinciple,buildsuchaweapon. Similarly,
it is shown that “boosting,” i.e., the technique of using a small amount of tritium
to enhance the performance of a fission bomb, is also much easier than generally
assumed. In particular, usingthistechnique, buildinghighlyefficient and reliable
atomic weapons using reactor-grade plutonium is straightforward. Moreover, in-
dependently of the type of fissile material used, the construction of “simple” and
“deliverable” tritium-boosted nuclear weapons can be easier than the construc-
tion of primitive Hiroshima or Nagasaki type atomic bombs. In May 1998, both
India and Pakistan showed that they had successfully developed boosted fission
weapons. Moreover, India claimed to have tested an advanced hydrogen bomb
concept,anditisbelievedthattwooftheirotherfourdeviceshaveusedplutonium
thatwas notclassified as weapons grade.
Thesecondchapterisatechnical andlegalanalysisofthenucleartestswhich
are allowed by the CTBT: microexplosions and subcritical experiments. It is
found that this treaty explicitly forbids only nuclear explosions in which a diver-
gent fission chain reaction takes place. Therefore, it is possible to develop new
typesoffissionexplosivesinwhichsubcriticalfission-burnistheyieldgeneration
mechanism. Similarly, new kinds of fusion explosives, in which the trigger is no
longera fissionexplosive,arelegalundertheCTBT.
Thethirdchapterisdevotedtothemilitaryapplicationsofinertialconfinement
fusion (ICF) and other pulsed-power technologies. The capabilities of modern
v
vi
laboratory simulation techniques for weapons physics research are shown to sig-
nificantly overlap with those of underground nuclear testing. Moreover, these
technologies are found to enable the study of a number of physical processes —
especially electromagnetic energy cumulation techniques and advanced nuclear
processes that are not restricted by existing arms control treaties — which are
useful in refining existing nuclear weapons and essential in developing fourth
generationnuclearweapons.
Thefourthchapterisdevotedtofourthgenerationnuclearweapons. Thesenew
fissionorfusionexplosivescouldhaveyieldsintherangeof1to100tonequivalents
ofTNT,i.e.,inthegapwhichtodayseparatesconventionalweaponsfromnuclear
weapons. These relatively low-yield nuclear explosives would not qualify as
weapons of mass destruction. Seven physical processes which could be used to
makesuchlow-yieldnuclearweapons,ortomakecompactnon-fissiontriggersfor
largescalethermonuclearexplosions,areinvestigatedindetail: subcriticalfission-
burn, magnetic compression, superheavy elements, antimatter, nuclear isomers,
metallichydrogenandsuperlasers(i.e.,ultrapowerfullaserswithintensitieshigher
than1019 W/cm2).
The conclusion stresses that considerable research is underway in all five
nuclear-weaponStates(aswellasinseveralothermajorindustrializedStatessuch
as Germany and Japan) on ICF and on many physical processes that provide the
scientificbasisnecessarytodevelopfourthgenerationnuclearweapons. Substan-
tial progress has been made in the past few years on all these processes, and the
construction of large ICF microexplosion facilities in both nuclear-weapon and
non-nuclear-weapon States is giving the arms race a fresh boost. The world runs
the risk that certain countries will equip themselves directly with fourth genera-
tionnuclearweapons,bypassingtheacquisitionofpreviousgenerationsofnuclear
weapons.
In this context, the invention of the superlaser, which enabled a factor of one
millionincreaseintheinstantaneouspoweroftabletoplasers,ispossiblythemost
significant advance in military technology of the past ten years. This increase is
of the same magnitude as the factor of one million difference in energy density
between chemicaland nuclearenergy.
A major arms control problem of fourth generation nuclear weapons is that
their development is very closely related to pure scientific research. The chief
purpose of the CTBT is to freeze the technology of nuclear weapons as a first
step toward general and complete nuclear disarmament. In order to achieve that,
it is necessary to implement effective measures of preventive arms control, such
as international legally binding restrictions in all relevant areas of research and
development,whethertheyare claimedtobeformilitaryorcivilianpurposes.
Contents
Executive summary v
Acknowledgments xiii
Introduction xv
Units,
conversion factors
and metricprefixes xvii
1 The PhysicalPrinciples ofThermonuclear Explosives 1
1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 ISRINEX 2.6 physics . . . . . . . . . . . . . . . . . . . . . . . . 2
1.3 Fissionexplosivesand boosting. . . . . . . . . . . . . . . . . . . 7
1.4 Modernboostedfissionexplosives(Figs.1.1–1.2) . . . . . . . . . 11
1.5 Theprincipleofthehydrogenbomb . . . . . . . . . . . . . . . . 18
1.6 TheTeller-Ulam method(Fig.1.3) . . . . . . . . . . . . . . . . . 22
1.7 “Mike,”thefirst hydrogenbomb(Figs.1.4–1.7) . . . . . . . . . . 27
1.8 B-28: Thefirst “miniature”
multi-purposeH-bomb(Figs.1.8–1.10) . . . . . . . . . . . . . . 32
1.9 1970-1980thermonucleardesigns(Fig.1.11) . . . . . . . . . . . 36
1.10 Thermonucleardetonationwavesand
sparkignition(Fig.1.12) . . . . . . . . . . . . . . . . . . . . . . 39
2 Nuclear WeaponsDevelopment under the CTBT 59
2.1 TheComprehensiveTestBan Treaty . . . . . . . . . . . . . . . . 59
2.2 Subcriticaltestsand treaty limitations . . . . . . . . . . . . . . . 60
2.3 Microexplosionsandtreaty limitations . . . . . . . . . . . . . . . 62
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viii
2.4 Nuclear explosionsand the“zero-yield”CTBT . . . . . . . . . . 65
2.5 Nuclear activities not prohibited by the CTBT and advanced nu-
clear processes . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
3 Nuclear WeaponsApplicationsofInertial Confinement Fusion 71
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
3.2 Inertial Confinement Fusion(Fig.3.1) . . . . . . . . . . . . . . . 72
3.3 Total energy versusenergy density(Fig.3.2) . . . . . . . . . . . . 78
3.4 Equationofstate(Fig.3.3) . . . . . . . . . . . . . . . . . . . . . 80
3.5 Opacity (Figs.3.4–3.5) . . . . . . . . . . . . . . . . . . . . . . . 81
3.6 Compressibleturbulence(Figs.3.6–3.7) . . . . . . . . . . . . . . 83
3.7 Radiation-drivenhydrodynamics(Fig.3.8) . . . . . . . . . . . . . 84
3.8 Pure hydrodynamics(Fig.3.9) . . . . . . . . . . . . . . . . . . . 85
3.9 Radiativetransport(Fig.3.10) . . . . . . . . . . . . . . . . . . . 85
3.10 ICF and nuclearweapons proliferation . . . . . . . . . . . . . . . 85
4 FourthGeneration NuclearWeapons 103
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
4.2 Subcritical and microfissionexplosives(Figs.4.1–4.2) . . . . . . . 106
4.3 Transplutonicand superheavy elements . . . . . . . . . . . . . . 110
4.4 Antimatter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
4.5 Nuclear isomers . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
4.6 Super-explosivesand metallichydrogen . . . . . . . . . . . . . . 130
4.7 Pure-fusion explosives . . . . . . . . . . . . . . . . . . . . . . . 136
4.8 Superlasers (Figs.4.3–4.4) . . . . . . . . . . . . . . . . . . . . . 146
4.9 Technologyoffourthgeneration
nuclearweapons (Fig.4.5) . . . . . . . . . . . . . . . . . . . . . 152
5 Conclusion 163
6 Bibliography 171
6.1 Nuclear armamentand disarmament . . . . . . . . . . . . . . . . 171
6.2 Fissionweapons . . . . . . . . . . . . . . . . . . . . . . . . . . . 176
6.3 Fusionweapons . . . . . . . . . . . . . . . . . . . . . . . . . . . 177
6.4 Third andfourth generationnuclearweapons . . . . . . . . . . . 180
6.5 Inertial confinementfusion . . . . . . . . . . . . . . . . . . . . . 181
6.6 Subcritical fissionand microfission . . . . . . . . . . . . . . . . . 185
6.7 Shockwaves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186
6.8 Equationsofstate . . . . . . . . . . . . . . . . . . . . . . . . . . 187
6.9 Opacities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188
6.10 Instabilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188
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6.11 Superheavy elements . . . . . . . . . . . . . . . . . . . . . . . . 189
6.12 Antimatter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192
6.13 Nuclearisomers . . . . . . . . . . . . . . . . . . . . . . . . . . . 198
6.14 Super-explosivesand metallichydrogen . . . . . . . . . . . . . . 201
6.15 Pure-fusionexplosives . . . . . . . . . . . . . . . . . . . . . . . 204
6.16 Cumulationofenergy . . . . . . . . . . . . . . . . . . . . . . . . 208
6.17 High-energy-densityand pulsed-powerfacilities . . . . . . . . . . 209
6.18 Superlasers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211
6.19 Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215
6.20 Additionalreferences . . . . . . . . . . . . . . . . . . . . . . . . 216
x