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Chapter 1
Dealing with the
civilian/military ambivalence
toward tritium
1.1 Introduction
Tritium has various military as well as civilian applications. The latter have always
lagged behind military applications and were partly enabled or triggered by the
availability of tritium from military production.
Tritium is believed to be used by all nuclear weapon states in most of their
nuclear warheads. Even de facto nuclear weapons states have engaged in tritium
technology. Tritium on its own is neither suﬃcient to produce nuclear weapons, nor
a necessary component to design a simple nuclear warhead. It becomes strategically
signiﬁcant only when it is combined with either plutonium or highly enriched
uranium-235 (HEU) in a complex design which requires a high degree of technical
competence. Whereas plutonium-239 and uranium-235 are the ﬁssile materials that
provide the yield, the main military application of tritium is to fuse it with deuterium
so as to release neutrons which in their turn increase (“boost”) the eﬃciency
and thus the explosive yield of a given amount of plutonium-239 and uranium-235.
Due to its short half-life of 12.3 years, tritium has to be replenished on a regular basis.
Since no natural resources are available, tritium has to be produced in nuclear
reactors, which implies the diversion of nuclear energy for military purposes.
With the horizontal and vertical proliferation of know-how and the capacity to
produce nuclear weapon, tritium and tritium technology are clearly gaining signiﬁcance
within the nuclear proliferation process. This is exempliﬁed by the partially
successful attempts of undeclared nuclear weapons states to acquire tritium and
tritium technology or by the large investments planned by the U.S. to develop and
establish a new military tritium production facility despite the progress in nuclear
disarmament.
In the 1990s, the control of tritium became a topic on the political agenda which
resulted in several activities to strengthen and harmonize export control measures
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“Kalinowski” — 2004/2/16 — page #16
and in a mandate for EURATOM to control tritium that is being supplied by
Canada to fusion research facilities in EURATOM member states. A further prominent
proposal is to consider tritium during negotiations for a veriﬁed agreement on
a production cutoﬀ for ﬁssile materials. Tritium might even play a key role in the
nuclear disarmament process due to its radioactive decay.
Neither the quantity of tritium nor its mode of production, chemical state, physical
condition, or degree of purity determines or indicates an intended military or
civilian use. Since it is impossible to physically diﬀerentiate between “military tritium”
and “civilian tritium,” the respective sociotechnological environment has to
be taken into account if a judgment is required. Since physical barriers can never be
completely tight, the most eﬃcient way to prevent the diversion of tritium for military
purposes, besides binding and veriﬁed political commitments, is to minimize
any production and application.
1.2 Tritium and tritium technology
Tritium1
(symbol: T or 3
H) is the superheavy isotope of hydrogen, which is
the lightest element with just one proton in its nucleus. Ordinary hydrogen
(H or 1
H) has no neutron; heavy hydrogen (D or 2
H), also known as deuterium,
has one neutron; and tritium has two neutrons in its nucleus. Their relatively large
mass diﬀerences have no signiﬁcant inﬂuence on the chemical behavior of the three
hydrogen isotopes. Tritium is a gas and appears in molecular form as T2. It can
substitute ordinary hydrogen in any of its compounds. Of particular importance
is its oxidized form as “superheavy” water (T2O), as tritiated water (HTO), or
tritiated heavy water (DTO). The main physical data are summarized in Table 1.1.
Table 1.1 Main physical data of tritium.
atomic weight 3.017
half-life [years] 12.36
decay path beta (100%)
decay product 3
He
maximum beta energy [keV] 18.6
average beta energy [keV] 5.7
speciﬁc activity of T2 [TBq/g] 358
speciﬁc activity of T2O [TBq/g] 268
speciﬁc activity of HTO [TBq/g] 53.7
volume of 1 g tritium at standard temp. and pressure [l] 3.720
decay heat [W/Bq] 9.2×10−16
biological half-life [days] 8−12
dosage produced by 1 GBq in man (70 kg) [mSv/day] 1.19
The physical properties of the three hydrogen isotopes diﬀer signiﬁcantly. Their
diﬀerent mobilities and boiling points can be used for isotopic separation. The
most remarkable characteristic of tritium as compared to the other two hydrogen
isotopes is its radioactive decay. It emits a beta particle to become the stable
isotope helium-3.
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“Kalinowski” — 2004/2/16 — page #17
T → 3
He + β−
+ ¯νe + 18.6 keV . (1.1)
The half-life of tritium is 12.3 years, i.e., a given quantity of tritium decreases
at a rate of about 5.5% per year by radioactive decay. The speciﬁc activity of
pure tritium is 360 TBq/g. Due to its decay, tritium does not accumulate. In
the biosphere, tritium exchanges rapidly and establishes equilibria between various
systems (International Atomic Energy Agency [IAEA], 1979). It is not possible to
ﬁnd any water sample which does not contain tiny amounts of tritium.
The bulk of natural hydrogen is the normal hydrogen and some 0.015% is deuterium.
The concentration of naturally produced tritium is one atom of tritium
in 1018
atoms of hydrogen. Accordingly, the unit for tritium concentration has
been deﬁned as 1 TU = 10−18
. This corresponds to 0.120 Bq/l. The whole natural
inventory of tritium in the hydrosphere amounts to a mere few kilograms.
Artiﬁcial production and emission of tritium has increased the natural concentration
several times. About one hundred kilograms have been emitted from artiﬁcial
sources, basically by atmospheric testing of nuclear weapons in the late 1950s and
early 1960s. Table 1.2 shows the total steady state inventory of the biosphere from
natural and artiﬁcial sources.
In terms of radiation safety, tritium is a major radionuclide emitted by nuclear
reactors and reprocessing plants during normal operation.2
A survey on the containment
performance of various tritium facilities and the radiological impact of
tritium emissions showed that the radiation dosages received by the most exposed
individual during normal operation of large facilities can come close to the regulatory
limits (Kalinowski, 1993). However, in the case of accidents at proposed fusion
reactors which use state-of-the-art technology, compliance with regulatory limits
cannot be guaranteed (Kalinowski, 1993).
The natural abundance of tritium is so low that it cannot be economically exploited.
It has to be produced artiﬁcially by means of a nuclear reaction. This can
be done in nuclear reactors (see Section 2.4). In thermonuclear weapons, tritium is
produced in situ from lithium deuteride via the following nuclear reaction:
6
Li + n → α + T + 4.78 MeV . (1.2)
Most civilian applications use the energy of the beta particle which results from
the decay of tritium (see Section 1.3.1). A mixture of gaseous tritium and deuterium
is used in nuclear weapons as a source of neutrons (see Section 1.3.2). For this
purpose the following nuclear reaction is used:
D + T → α + n + 17.6 MeV . (1.3)
This reaction releases fusion energy, but the insertion of gaseous tritium adds little
to the explosive yield of the nuclear weapon. In thermonuclear weapons, tritium is
produced in situ and most of the total energy release originates from the fusion of
tritium and deuterium (see Section 1.3.2).
If the amount of tritium handled exceeds a certain limit, it will be necessary to
undertake a certain technological eﬀort in order to contain the tritium and to protect
workers and the environment from contamination. With the exception of some medical
and tracer research applications, tritium beyond this limit is usually required.
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“Kalinowski” — 2004/2/16 — page #18
Table 1.2 Tritium inventory in the biosphere from natural atmospheric production, nuclear
weapon tests, and emissions from nuclear facilities.
source production rate
[triton/(cm2
s)] a
production
or emission
rate [g/y]
steady state
content in the
biosphere [kg]
remark
natural
prod.
0.12−1.2 100−1000 1.8−18 review of 13 studies
(1953−67)
(UNSCEAR, 1977)
natural
prod.
0.14−0.90 110−700 1.9−12 review of 5 studies
based on cosmic
ray and nuclear
cross-section data
(Phillips and
Easterly, 1980)
natural
prod.
0.25±0.08 200±64 3.5±1.1 good estimate (Craig
and Lal, 1961)
natural
prod.
0.14−2.0 110−1600 1.9−28 review of 5 studies
based on
geochemical
inventory (Phillips
and Easterly,
1980)
natural
prod.
0.5±0.3 400±240 7.0±4.2 best estimate (Craig
and Lal, 1961)
natural
prod.
0.39+0.09−0.29 310+70−230 5.5+1.2−4.0 more recent study
R¨other (1980)
emissions − 500−700 9−12 see footnote b
nuclear
expl.
− − 90−56+230 see footnote c
total 100−200 see footnote d
a A triton is the completely ionized nucleus of tritium. The earth surface area is 510.1×106 km2.
b In the past, the largest contribution to tritium releases from nuclear facilities stemmed from
emissions of tritiated heavy water from nuclear power plants at a rate of some 1% of the inventory
per year. Reprocessing of spent fuel constitutes the second largest contribution. A signiﬁcant
increase in this kind of release is expected for the next ten years. See Section 2.6.9.
c The total release of tritium by nuclear weapons tests in the late 1950s and early 1960s was about
465 kg (United Nations Scientiﬁc Committee on the Eﬀects of Atomic Radiation (UNSCEAR),
1977). The ﬁgure was calculated from an estimate of the total inventory in 1970 (300 kg).
Allowing for decay, some 90 kg did exist at the end of 1991. The total explosive power of
thermonuclear bomb tests above ground was 318 Mt TNT. Estimates for the production factor
range from 190 to 1800 PBq/Mt TNT (Phillips and Easterly, 1980). Therefore, the total tritium
production from thermonuclear bomb tests lies between 170 and 1600 kg, i.e., between 34 and
320 kg did still exist. Contributions from ﬁssion bomb tests are less than 4 kg.
d According to CFFTP (1988), the total amount in the atmosphere (0.6 kg, 0.4%), continental
waters (18 kg, 12.5%), and oceans (129 kg, 90%) was 144 kg in 1986. According to UNSCEAR
(1977) 7.2% can be found in the atmosphere, 27% in land surface and biosphere, and 65% in
oceans.
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“Kalinowski” — 2004/2/16 — page #19
Safe handling of tritium involves various technology components for transporting,
storing, measuring, handling, and containing tritium. A minimum conﬁguration for
tritium handling encompasses storage (e.g., uranium getter storage), instruments for
inventory measurements (e.g., a steel tank with pressure gauge, thermometer, and
mass spectrometer), equipment for transfer processes (e.g., pipes, loading device,
vacuum pump), provisions for radiation protection (glove box, emergency device to
remove tritium from air), devices for emission control and monitoring (molecular
sieve and catalyst for oxidizing tritium gas, stack, and room air monitor), and a
waste treatment facility.
The establishment of a complete production line necessitates the use of more
sophisticated tritium technology for breeding (irradiation target for nuclear reactor),
puriﬁcation, and isotopic separation (e.g., gas chromatograph) (see Section 2.4 and
Albright and Paine, 1988).
Measurement of tritium concentrations in air for radiation monitoring is very
diﬃcult. Tritium is one of the most challenging isotopes to detect because it emits
only beta rays which have an exceptionally low energy (maximum of 18.6 keV).
The average travel distance of these beta particles before being absorbed is
some 5 mm in air and 6 µm in water. The most widely used method to measure
tritium is to apply a scintillation detector. In this case, air or water samples
are mixed with a liquid scintillator. Gas proportional counters can be employed if
the tritium to be measured is made to replace an ordinary hydrogen atom in the
counter gas methane.3
1.3 The use of tritium
1.3.1 Civilian uses of tritium
Tritium is oﬀered commercially as gas with a typical purity of about 90% (Lieser,
1980) or as tritiated water.
The development of commercial tritium applications was intensiﬁed in the early
1960s, primarily because excess amounts of tritium were made available by the U.S.
Atomic Energy Commission (USAEC). USAEC made 100 g of tritium available in
1959, which was subsequently sold by the Oak Ridge National Laboratory (ORNL)
for peaceful applications. In comparison, 4.1 g of tritium had been sold in 1958,
and only 1.3 g in the period between 1948 and 1957 (Anonymous, 1959). Tritium
was primarily welcomed as a pure beta emitter to replace radium in self-powered
light sources whose gamma radiation causes unacceptable radiation doses.
The historical development of worldwide civilian demand can be seen in
Figure 1.1. At the end of the 1960s, the worldwide consumption of tritium was
about 20 g per year. In the early 1970s, the European tritium industry put annually
about 30 g of tritium in luminous paints and 20 g in self-luminating lights (“betalights”)
(Desroches, 1973). The worldwide demand increased slightly to 100 g per
year in the mid 1970s, basically for radio-luminous paints and self-luminating lights
(“beta-lights”). For 1978 the amount of tritium used in consumer goods was estimated
to be 100 g in Europe and 200 g worldwide (Krejci, 1979). In 1979 the
commercial consumption of tritium peaked4
at approximately 800 g, but in 1980 it
dropped markedly back to about 100 g/y because safety regulations were tightened
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“Kalinowski” — 2004/2/16 — page #20
1970 1975 1980 1985 1990 1995
0
100
200
300
400
500
600
700
800
900
yearlyamount[g/y]------>
time [y] ------>
Figure 1.1 Historical development of worldwide civilian demand for tritium. Values for
1991 to 1995 are estimates.
after concerns about radiological problems arose. Since then, the yearly tritium demand
slightly increased again to about 400 g/y at the beginning of the 1990s. The
international trade in the 1980s was on average slightly more than 220 g per year.5
Demands for fusion research have increased their share to about 10%. Shipments
of more than 1 g are received from manufacturers at most two to ﬁve times a year.
A single production charge for luminous paints contains a maximum of 0.1 g of tritium.
Only 4 out of 21 large commercial tritium manufacturing and trading facilities
are located in the nonnuclear-weapons states, Canada, Germany, and Switzerland
(see Appendix A on tritium facilities).
Nearly all civilian demand was satisﬁed by supplies from the ORNL sales oﬃce.6
Its price has risen from $10,000 per gram in the early 1980s to $29,000 in the late
1980s.7
It is conceivable that China, the U.K.,8
France, and Russia9
would be able to
export tritium originating from their military production in signiﬁcant quantities
(several tens of grams). Smaller amounts of tritium are available from civilian
sources in Belgium10
and France.11
In the early 1990s, Ontario Hydro (Canada)
appeared as the main supplier of tritium from civilian sources on the world market.
This company initially intended to gain approximately 2.5 kg of tritium per year
from its newly built Tritium Removal Facility (TRF) at Darlington. It started to
undertake a special eﬀort with the support of the Canadian government to establish
new applications of tritium (especially runway landing lights) to increase the market
and to sell as much as possible of its tritium. The rest of the material is left to
decay.
The main importing countries are the U.K., Japan, and Switzerland. The
stated uses are basically for self-powered lights and radio-luminous paint. Table 1.3
presents the variety of commercial products which make use of tritium. Most
of them contain very small quantities of tritium, as can be seen from the table,
which shows the diﬀerent applications ordered by the decreasing quantities typically
required.
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“Kalinowski” — 2004/2/16 — page #21
Table 1.3 Tritium in commercial products.
product content content
[GBq] a
[µg]
radio-luminous products containing tritium in paint or plastic
compasses 0.2−2 0.5−5
instrument dials and markers, automobile shift
quadrants
1 2.5
sprit levels 0.2−1 0.5−2.5
timepieces 0.04−1 0.1−2.5
automobile lock illuminators 0.07−0.6 0.2−1.5
bell pushes, rims for underwater watches 0.01 0.03
radio-luminous products containing tritium in sealed tubes b
runway landing lights for remote airﬁelds <40,000 <100,000
exit signs 70−4000 200−10,000
helicopter rotor blade tip markers 2000 5000
night sight for artillery weapons 70−2000 200−5000
aircraft instrument panel illumination 70−700 200−2000
map readers for night use 200 500
markers 150 250
instruments, signs and indicators, step markers,
mooring buoys and lights
70 200
marine compasses 7−70 20−200
public telephone dials 20 50
night sights for small arms (pistols, riﬂes) 4−20 10−50
timepieces, ordinary compasses 7−15 20−40
backlights for liquid crystal displays in watches,
light switch markers
7 20
bell pushes 0.4 1
electronic and other devices
tritium targets for neutron source, typical size 0.04−100 0.1−300
tritium targets for neutron source, large special <220,000 <615,000
gas chromatographs 10 25
electronic tubes 0.0001−0.4 0.0003−1
antistatic devices contained in precision balances 0.04 0.1
cold-cathode tubes 0.003 0.008
glow lamps 0.0004 0.001
low-energy electric lights 0.2×10−6
0.5×10−6
a Figures are taken from International Atomic Energy Agency (1979) and other sources.
b These products are sometimes called “beta lights” or gaseous tritium light sources (GTLSs).
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There are also some applications of tritium in research (Evans, 1974). Most
research applications require only very small quantities (a few µg or less). In the
following list the various applications are arranged in order of decreasing require-
ments:
• Fusion energy research (presently a few 100 g worldwide)12
In recent years, fusion research makes increasing use of tritium. The
main goal is to learn about the behavior of tritium in various components of
fusion reactors, such as breeder blankets, oﬀ-gas processing systems, structure
materials, etc. If a fusion power reactor ever started operation, it would
contain a steady inventory of a few kg and burn about 180 kg per GWey.
• 14 MeV neutron sources (up to 600 mg each) (Kobisk, 1989)
Tritium can be used for relatively compact generators of 14 MeV neu-
trons.13
These high energy neutrons are useful for various applications such
as neutron activation analysis, production of tiny amounts of special radionuclides,
and for the study of nuclear reactions induced by 14 MeV neutrons.
• Biological, medical, chemical, and geological research, especially as tracer
(µg quantities)
Tritium is frequently used as tracer for chemical compounds which contain
hydrogen. Some of the hydrogen is replaced by tritium. The behavior
of the labeled molecules (pathways, residence time, etc.) can be studied by
measuring the activity of diﬀerent samples. Tracer studies are conducted especially
in biology, medicine, physics, chemistry, agriculture, and geology. Small
amounts of tritium are used in experiments as a source of Bremsstrahlung or
beta particles.
1.3.2 Military uses of tritium
There are various military applications of tritium within the category of conventional
weapons. These are primarily dual-use applications, mostly using tritium
as self-powered light sources for conventional weapon systems. They are similar
to commercial applications of tritium and are included in Table 1.3. The largest
quantities of tritium for these applications are used in airﬁeld runway landing lights
like those employed during the U.S. invasion of Grenada.
Some tritium is used for research in inertial conﬁnement fusion (ICF). These
experiments are closely linked to nuclear weapons research (Schaper, 1991 and
Gsponer and Hurni, 1998).
The largest amount of tritium required for military purposes is used in nuclear
weapons. In these, tritium is mainly used to generate neutrons from fusion with
deuterium according to the following equation:
D + T → α + n + 17.6 MeV . (1.4)
The fusion energy released by this reaction does not contribute signiﬁcantly to the
total yield of the nuclear weapon.
Although attempts have been made to construct thermonuclear weapons which
do not require a ﬁssion primary, it is generally believed that they have not been
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“Kalinowski” — 2004/2/16 — page #23
successful. Some analysts (Gsponer and Hurni, 1998; Makhijani and Zerriﬃ, 1998;
Jones and von Hippel, 1998; and Jones et al., 1998) fear that this might change
with the increased research eﬀorts regarding thermonuclear weapons physics (U.S.
Department of Energy, 1996). Thus, tritium is neither suﬃcient nor necessary to
produce a nuclear weapon. Obviously, it is less signiﬁcant for nuclear weapons
than uranium and plutonium. However, it becomes strategically signiﬁcant as an
addition to ﬁssionable material. Tritium is believed to be a component of most
nuclear weapons currently in the stockpiles of all nuclear weapons states. Its primary
purpose is to increase (“boost”) the explosive yield of a given amount of ﬁssionable
material. Hence, the particular signiﬁcance of tritium for the nuclear arsenal is to
guarantee a higher total yield. Without tritium the total yield would be lower by
one order of magnitude (see Sections 1.6.2 and 1.6.3).
Tritium is further used for selectable yields, for radiation enhanced weapons,
and for the thermonuclear stage in fusion weapons. The use of tritium in nuclear
weapons, therefore, leads to vertical proliferation from ﬁrst-generation ﬁssion devices
to more sophisticated boosted or thermonuclear weapons.
The following list explains the diﬀerent uses and estimated quantities of tritium
in nuclear warheads:14
1. Neutron generator (0.1 mg): The nuclear ﬁssion chain reaction is started by a
shower of neutrons. In early weapon designs a bimetallic neutron source was
used for this purpose. Pulverized beryllium and an alpha emitter are mixed
and generate neutrons according to the nuclear reaction 9
Be + α → 12
C + n.
A Ra-Be neutron source with 10 Ci Ra-226 emits some 108
neutrons per second
(see, e.g., Lieser, 1980). Within the ﬁrst generation of neutrons15
this
source emits just one neutron. A stronger pulse of neutrons is desirable because
the higher the number of neutrons in the ﬁrst generation, the more
reliably can the beginning of the chain reaction be predicted.16
Precise timing
of the pulse is more important, however, as it has a considerable impact on
the yield.
This can be achieved with an electrostatic neutron generator in which
deuteron ions accelerated by a high voltage strike a metal tritide target.17
Typical targets contain up to 0.1 mg of tritium (see, e.g., Evans, 1974). Neutron
showers with some 5×1012
neutrons per second are available for civilian
purposes (Lieser, 1980). Such neutron generators were ﬁrst used by the U.S.
in 1953 and are today as small as a ﬁst (Cochran, 1987a).
In contrast to the bimetallic neutron source, this type of neutron generator
is an external neutron source, i.e., neutrons are shot from the outside into
the core of the critical mass. The cavity in the core is a precondition for the
boosting which is described in the next paragraph.
2. Boosted ﬁssion weapons and boosted primaries in thermonuclear weapons
(2–3 g):18
The principle of fusion-boosted ﬁssion bombs was declassiﬁed in
1974.19
In these devices a mixture of tritium and deuterium gas is injected
from an external gas capsule at high pressure (about 107
Pa) into the hollow
core of the plutonium sphere before the chain reaction is initiated. For a short
time, both temperature and pressure in the center of the nuclear explosion are
high enough to allow tritium and deuterium to fuse. The neutrons released
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“Kalinowski” — 2004/2/16 — page #24
from this fusion induce further ﬁssions, thereby increasing the eﬃciency of the
ﬁssionable core and possibly of the surrounding tamper (fertile material, e.g.,
uranium-238). As a result, the yield can be multiplied — depending on the
ﬁssion eﬃciency without boosting — by a factor of 2 to 10 (Hansen, 1988) or
even 100.20
As a consequence, boosted weapons can achieve explosive yields up to
400 kt,21
but are still heavy. However, thermonuclear weapons with boosted
primaries can have high yield-to-weight ratios (see Figure 1.4), allowing highyield
(100 to 500 kt) warheads to be small and light enough (100 to 400 kg) to
ﬁt into long-range missiles with multiple warheads, as well as into torpedoes
and artillery shells (see Figure 1.4).
In addition, it may be assumed that boosted weapons are more reliable
than ordinary ﬁssion bombs concerning their explosive yield, because the reduced
quantity of plutonium is easier to compress by means of a conventional
explosion and thus has a reduced probability of predetonation. To put it
another way, the probability of predetonation remains the same when a plutonium
bomb with a lower content of plutonium-239 utilizes tritium.
Boosting is believed to be applied in most of the small ﬁssion weapons and
in all triggers of thermonuclear weapons in the current U.S. nuclear arsenal
(see Section 1.6.2).
The quantity of tritium used for boosting (2–3 g) can be estimated from
the U.S. stockpile on the assumption that all nuclear weapons make use of
boosting and that not all military tritium is used for this purpose.22
The complete
fusion of 3 g of tritium with 2 g of deuterium releases enough neutrons
to induce ﬁssion of 240 g of plutonium. The ﬁssion releases more than 4 kt
of TNT, whereas the fusion energy contributes no more than 0.4 kt. In thermonuclear
weapons the largest fraction of the energy comes from fusion (see
item 5 below).
A high purity is required for the mixture of tritium and deuterium.23
3. Selectable yield (2–3 g): This is a special feature used for some boosted warheads.
The desired yield can be selected immediately before its delivery by
varying the timing of its application or by inserting more or less (from zero to
all) capsules each containing a fraction of the total tritium. There are some
other methods that can be used as well to enable yield selection. The new
modiﬁcation of the B61 (mod. 11) has the widest known range of yields from
0.3 to 340 kt (Mello, 1997).
4. Neutron bomb (Gsponer, 1984 and Huaqiu, 1988) (10–30 g):24
Tritium is used
in a similar way in radiation enhanced weapons (neutron bombs), which are
designed to maximize the portion of energy which is carried by the neutrons.
The 14 MeV neutrons generated by fusion have a higher probability of escaping
than of being stopped by inducing further ﬁssions. Therefore, these
weapons have a comparatively low yield (about 1 kt of TNT) and a large ﬂux
of high-energy neutrons. The amount of tritium needed for this sort of nuclear
weapons is of the order of a few tens of grams.
When no tritium is inserted, a neutron bomb works like a simple low-yield
ﬁssion weapon.
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“Kalinowski” — 2004/2/16 — page #25
5. Thermonuclear weapon: The primary material of thermonuclear stages is LiD.
Tritium is bred in situ from lithium by capturing a neutron. Some of the
lithium hydride can be added in the form of LiT. This is not necessary, but is
probably done in some weapon designs to facilitate the beginning of the fusion
reaction (see, e.g., Winterberg, 1981). Quantities are not publicly known.
Most information regarding the use of tritium for nuclear weapons is classiﬁed.
More details are described elsewhere (see, e.g., Albright and Paine, 1988; Cochran
et al., 1984; Gsponer and Hurni, 1998; Hansen, 1988; Seifritz, 1984; and Winterberg,
1981). All quantities given above are educated guesses which have been neither
conﬁrmed nor denied by oﬃcial sources.
The strategic signiﬁcance of tritium for the nuclear arsenal is to provide a high
total yield or a high yield-to-weight ratio (see Section 1.6.2).
The military facilities for the production of tritium and their capacities in the
nuclear weapons states are described in Section 2.7. Tritium-related activities in de
facto nuclear weapon states are dealt with in Section 1.7.
1.3.3 Civilian/military ambivalence of tritium
Tritium has various military (nuclear and nonnuclear-weapons related) as well as
civilian (industrial and scientiﬁc) applications.25
The relationship between civilian
and military uses of tritium becomes particularly apparent when reviewing the historical
development.
History of civilian and military uses of tritium:26
1934 The British scientist Lord Rutherford discovers tritium by a nuclear reaction.
1939 Luis Alvarez from the University of California discovers the radioactive decay
of tritium.
1944 During World War II, the ﬁrst calculations regarding the use of fusion energy
in nuclear weapons are undertaken by scientists of the Manhattan Project in
Los Alamos.
1950 Under the impression that the ﬁrst Soviet nuclear weapon test has been
carried out, research on thermonuclear weapons is enhanced in the U.S.
1951 On May 8, tritium is used for the ﬁrst time in a nuclear weapon test by the
U.S. During “Operation Greenhouse,” a fusion-boosted ﬁssion device with the
code name “George” is tested on the Enewetak Atoll in the West Paciﬁc.
1952 On November 1, the U.S. explodes the ﬁrst thermonuclear device at the same
site. This shot, called “Mike,” weighs 82 tonnes and has a yield of 10.4 Mt of
TNT, that is, 500 times the yield of the Nagasaki bomb.
1955 At the Savannah River Plant (South Carolina, U.S.), the ﬁrst military reactor
dedicated to the production of tritium starts operation. Further military
tritium production reactors are commissioned at Marcoule (France, 1956),
Chelyabinsk (U.S.S.R., 1957), Chapel Cross (U.K., 1958), China (1968), and
Dimona (Israel, 1968).
© 2004 by CRC Press LLC