Rend. Fis. Acc.

Lincei (2014) 25:119–126

DOI 10.1007/s12210-013-0247-z

ANTHROPOCENE - NATURAL AND MAN-MADE ALTERATIONS OF THE EARTH

Nuclear energy and Anthropocene

Ettore Fiorini

Received: 23 April 2013 / Accepted: 5 July 2013 / Published online: 15 October 2013
Ó The Author(s) 2013. This article is published with open access at Springerlink.com

Abstract After a short introduction on the basic physical countries. This has been accomplished so far only by fission,
problems of the application of nuclear physics to unfortunate and the hopes of civil production by fusion have been so far
military scopes and to civil production of nuclear energy we frustrated. We will therefore be concerned here only to the
will consider their relatively recent and possible important former of these processes.
impact on Anthropocene. Special emphasis will be devoted The potentiality to produce nuclear energy can be easily
to the present continuous production of nuclear wastes and to understood by inspecting Fig. 1 where the binding energy
their disposal, particularly in deep storage locations. of a nucleus is divided by its atomic number A. It can be
seen that the most stable nuclei present a maximum mean
Keywords Nuclear energy  Nuclear wastes  Disposal  binding energy when A is around 60. As a consequence
Deep storage energy can be obtained either by splitting heavy nuclei like
235
U (fission) or unite light ones (fusion).
1 Introduction
2 Nuclear fission
The effects of nuclear energy in Anthropocene are relatively
recent and can be due in principle both to fission and fusion.
Civil nuclear energy by fission is mainly produced by
The military application of nuclear fission led about seven
capture on 235U of thermal neutrons with a very low energy
decades ago to the nuclear test in New Mexico followed by
(about 0.025 eV).
the tragic events of Hiroshima and Nagasaki. From then the
application of fission and fusion to nuclear tests produced nthermal ¼ [ 235 U þ X þ Z þ m nfast
considerable and sometimes hidden effects in the environ- where X and Z are fission fragments and the number m of
ment. Since about six decades interest was also addressed to generated neutrons is in average of 2.47. The energy of these
the civil production of nuclear energy which has now reached neutrons is, however, too large to produce further fissions and
a considerable percentage in the energy balance of many has to be reduced by means of a suitable moderator (Carbon,
H2O, D2O etc.). Moderated neutrons can then produce further
This contribution is the written, peer-reviewed version of a paper fissions and give rise to the chain reaction shown in Fig. 2.
presented at the conference ‘‘Anthropocene—Natural and man-made The role played by Uranium isotopes in nuclear fission is
alterations of the Earth’s fragile equilibrium’’, held at Accademia reported in Table 1. The captured thermal neutron delivers to
Nazionale dei Lincei in Rome on November 26–27, 2012.
the nucleus an excitation energy which should be larger than
E. Fiorini (&) the activation energy needed to produce fission. Only the 233
Dipartimento di Fisica and INFN, Università di Milano-Bicocca, and 235 isotopes of Uranium obey this rule, with isotopic
Piazza della Scienza 3, 20126 Milan, Italy abundances of 0.005 and 0.72 %, respectively. The abun-
e-mail: ettore.fiorini@mib.infn.it dance of the former is too low for its use in a reactor, unless
E. Fiorini produced in other ways, while the one of 235U can be suffi-
Accademia Nazionale dei Lincei, Rome, Italy cient in some reactor, like the first one built by Fermi, but it

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Fig. 1 Mean binding energy as

a function of atomic number

Fig. 2 Scheme of nuclear

fission chain

Table 1 Properties of some relevant isotopes

has to be enriched in most of the power reactors presently
running. One can note the attractive properties of the artificial
Nucleus Binding energy Activation energy r (barn) isotope 239Pu which we will consider later.
232
Th 4.8 6.7 \10-6
233
U 6.8 5.85 531.8
235
U 6.5 5.9 579 3 Nuclear wastes
238
U 4.8 5.8 2.7 9 10-6
239
Pu 6.5 6.3 742 The main problem and challenge in the present and
especially in the future civil and unfortunately military

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Fig. 3 Proton versus neutron

number. Stable nuclei are shown
in black

development of nuclear energy stays in the unavoidable 2. Cosmogenic radioactivity due to activation by inter-
production of radioactive isotopes: the so called nuclear actions of Cosmic Rays
wastes. In heavy nuclei, the presence of neutrons with 3. Anthropogenic radioactivity due to isotopes produced
respect to protons has to be larger to keep them together, mainly by nuclear explosion or tests, by the production
overcoming the larger coulomb repulsion (Fig. 3). This is of nuclear energy or even of radioisotopes for medical
less true for fission fragments much richer in neutrons and/or other civil applications
and therefore unstable. They are below the line of the
stable nuclei evidenced in the figure and tend to stability
with a chain of beta decays of generally increasing half
4 Nuclear reactors
lifetime.
The presence of these isotopes of both civil and military
A draft of the first nuclear reactor constructed by Fermi in
origin adds to the natural radioactive environment as
the swimming pool of the University of Chicago and
shown in Fig. 4. Present environmental radioactivity is in
secretly sketched against the strict military secrecy laws is
fact due to.
shown in Fig. 5. We would like to stress that the scope of
1. Fossil radioactivity from pre-existing atoms like this reactor was not the production of energy, but just to
Uranium, Thorium or Potassium prove the possibility to produce a chain reaction for

Fig. 4 Present gamma

spectrum of the sum of fossil,
cosmogenic and anthropogenic
radioactivity

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Fig. 7 The Oklo l reactor: 1 Nuclear reactor zones. 2 Sandstone.

3 Uranium ore layer. 4 Granite

It could be of some interest for geologists that nuclear

reactors existed in Nature! In present reactors the natural
abundance of 235U (0.72 %) has to be increased by about
Fig. 5 The first reactor three times to allow the chain fission reaction to occur in a
reactor, but a moderator has to be present. Billions years
ago 235U and 238U existed with the same amount, but the
abundance of 235U decreased more rapidly than for 238U
due to the lower half lifetime (0.704 instead than 4.47
Gigayears). In geological times the ratio between isotopes
235 and 238 was therefore much larger than the present
one, but a chain fission could only occur in presence of a
suitable moderator. In some case, however, water was
present. A known and proved case was the Oklo reactor in
the African region of Gabon shown in Fig. 7 where
apparently a moderator like water or granite was present.
The occurrence of this reactor about 1.7 Gigayears ago was
geological suggested, but later also proved by specific
measurements which revealed a geologically abnormal
lack of 235U and the presence of isotopes which could only
be produced by a chain reaction. (Curtin University 2012).
Two major disasters due to nuclear reactors took place
so far: one in 1987 in Chernobyl (then USSR) and recently
in Fukushima (Japan).
The effect on environmental radioactivity by the Cher-
nobyl accident in Milan is shown by our gamma ray
spectrum of Fig. 8 recorded then. One can notice the pre-
sence of the radioactive isotopes of Iodine, Ruthenium and
Cesium in addition to the lines due to natural radioactivity.
We would like to note that, due to its relatively long life-
Fig. 6 A present power reactor time (30.07 years), a minor contribution from 137Cs due to
the Chernobyl accident is still present in air particulate in
military purpose. This brought to the nuclear military era Italy.
with great efforts for the development and test of nuclear Despite the much larger distance from Fukushima we
weapons. It was only with the sixties that interest was were able to detect recently the contamination of the iso-
devoted to reactors specifically constructed for the pro- topes of Cesium and Iodine (Clemenza et al. 2012) as
duction of energy (Fig. 6). shown in Fig. 9.

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Fig. 8 Additional
environmental radioactivity due
to the Chernobyl incident in
1986

Fig. 9 Evidence in Milan

particulate of the effects of the
Fukushima incident

5 Disposal of nuclear wastes related to the future destiny of nuclear energy and depends on
the quantity and lifetime of the produced radioactive iso-
Nuclear wastes come from various sources: military and civil topes. We can roughly classify these radioactive nuclei
reactors, nuclear tests and pacific application of nuclear according to their lifetime as shown in Table 2.
physics (medical, agricultural, industry). We will not be The general classification of nuclear wastes is unfortu-
concerned here with the third, since it is negligible with nately controversial and different among the various
respect to the first two. A great amount of wastes were pro- nuclear countries (Sook Jung et al. 2012). According to the
duced at the beginning of the nuclear era especially in USA International Atomic Energy Agency (IAEA) wastes can be
and in USSR for their competition in the production of classified as following:
atomic bombs. In particular the dangerous plutonium was
1. High-level wastes (HLW): wastes containing larger
produced also as a reactor fuel in the worry of lack of Ura-
concentrations of both short- and long-lived radionuc-
nium. Further wastes were and are continuously generated
lides than ILW and generally having an activity
for civil production of energy by the large number (almost
concentration of 104–106 Bq/g
500) of operating power reactors. The concern is obviously

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Table 2 Classification of nuclear wastes according to their lifetime

Lifetime Fission products
72
1–10 days Zn, 67Ga, 77As, 82Br, 90Y, 95Nb, 99Mo, 103Rh, 105Rh, 109Ag, 115Cd, 115I, 127Sb, 131Te, 131I, 132Te,129Xe,
133
Xe,135Xe,135Ba,140La, 143Ce, 147Pm, 14Pm, 151Eu, 153Eu, 155Eu, 161Gd, 161Tb, 166Dy, 166Ho
86
10–100 days Ru, 89Sr, 91Y, 95Zr, 95Nb, 103Ru, 115Cd, 117Sn, 124Sb, 126Sb, 125Te, 129Te, 131Xe, 131Cs, 143Pr, 147Nd, 151Pmk, 156Eu, 131Te,
131
Te, 131Te, 131Te,
119 123 121 127 134 144 147 154 135 151
100 days– Sn, Sn, Te, Te, Cs, Ce, Pm, Eu, Eu, Sm
10 years
10-5 9 108 years 85
Kr, 90
Sr, 93
Zr, 93
Nb, 99
Tc, 107
Pd, 107
Cd, 107
Ag, 121
Sn, 126
Sn, 129
I, 135
Cs, 137
Cs, 131
Te,
8 82 87 116 130 114 147 152
[5 9 10 years Se, Ru, Cd, Te, Nd, Sm, Gd,

2. Intermediate level wastes (ILW): wastes requiring a nuclear reprocessing reduces the volume and the long-term
greater degree of containment and isolation than that radiation hazard and heat dissipation capacity needed.
of nearer surface disposal Reprocessing does not, however, eliminate the political
3. Low level wastes (LLW): these wastes are suitable for and community challenges and require the need for the
near surface disposal. They generally have a limit of repository of nuclear wastes where they can be safely
400 Bq/g on average (4,000 Bq/g for individual pack- insulated from the biosphere for at least hundred thousand
ages) for longer lived alpha emitting radionuclides years (Pusch 1994; Ojovan and Lee 2005; Pusch 2008).
We will be concerned here with the deep storage for
In a simplified approach two categories can be consid-
geological times, because it can be closely connected with
ered from the storage point of view:
Anthropocene.
1. Low level materials to handle strongly radioactive In USA, a country heavily involved since the beginning,
parts of reactors (e.g., cooling liquid, contaminated like USSR, in the military applications of nuclear age many
parts), radioactive sources even from nuclear medi- equipments were contaminated with amounts of radioac-
cine, industry etc., with limited lifetimes to be tivity. This was mainly due to the production of nuclear
disposed for tens of years in pools or concrete weapons during WWII and the Cold War. They have been
structures shipped to WIPP (Waste Isolation Pilot Plant) where the
2. Actinides (in particular Plutonium) produced during contaminants are permanently isolated and stored. This site
fission, to be stored for geological time or reprocessed is used even now to store nuclear wastes, but it is presently
inadequate for the large amount of continuously produced
One way to solve the problem of nuclear wastes is to
radioactive material.
limit their production with new types of reactors, or to
Many hopes were addressed in USA on the so called
reduce the produced ones by partitioning and transmutation
Yucca project (Fig. 10) initiated in 1978 for a long-term
(Ojovan and Lee 2005; Sook Jung et al. 2012). The former
geological depository for spent nuclear fuel and high-level
process consists in separating out of the spent fuel the
radioactive wastes. Recently, however, after animated lit-
radiotoxic components, the latter is based on recycling
igation between the local agency for Nuclear Project of the
them in a way to minimize their toxicity and recover their
State of Nevada and the Obama Administration the Yucca
contained energy in a useful way. We note that one or the
Project has been definitely canceled (New York Times
Fukushima reactors was charged also with Plutonium. This
2011, May 9). This leaves United States civilians without

Fig. 10 The proposed Yucca

site

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Table 3 Presently studied sites for disposal of nuclear wastes

Country Facility name Location Waste Geology Depth Status

Argentina Sierra del Medio Gastre Granite Under discussion

Belgium High-level waste Plastic clay *225 m Under discussion
Canada OPG DGR Ontario 200,000 m3 Argillaceous 680 m Licence application 2011
L&ILW limestone
Canada Spent fuel Under discussion
China Under discussion
Finland VLJ Olkiluoto L&ILW Tonalite 60–100 m In operation 1992
Finland Loviisa L&ILW Granite 120 m In operation 1998
Finland Onkalo Olkiluoto Spent fuel Granite 400 m Under construction
France High-level waste Mudstone *500 m Siting
Germany Schacht Asse II Lower Salt dome 750 m Closed 1995
Saxony
Germany Morsleben Saxony- 40,000 m3 Salt dome 630 m Closed 1998
Anhalt L&ILW
Germany Gorleben Lower High-level waste Salt dome Proposed, on hold
Saxony
Germany Schacht Konrad Lower 303,000 m3 Sedimentary rock 800 m Under construction
Saxony L&ILW
Japan High-level waste Under discussion
Korea Gyeongju L&ILW 80 m Under construction
Sweden SFR Forsmark 63,000 m3 Granite 50 m In operation 1988
L&ILW
Sweden Forsmark Spent fuel Granite 450 m Licence application 2011
Switzerland High-level waste Clay Siting
United High-level waste Under discussion
Kingdom
USA Waste Isolation Pilot New Mexico Transuranic waste Salt bed 655 m In operation 1999
Plant
USA Yucca Mountain Project Nevada 70,000 ton HLW Ignimbrite 200–300 m Proposed, canceled 2010

any long-term storage site for high-level radioactive waste 6 Conclusions

apart WIPP.
Deep geologic disposal has been and is being studied by The future of the production of energy of nuclear origin is
practically all nuclear countries since several decades, the object of animated economical, political, environmental
including laboratory tests, as shown by Table 3 (Wikipedia and even ethical discussions. There is no doubt, however,
2012). The need for safe disposal of high-level nuclear waste that the major problem, despite in some way the future
(HLW) has been in focus of the International Atomic Energy destiny of nuclear energy, is the need to dispose nuclear
Agency and of a number of national authorities for decades. wastes. Even if new types of reactors capable to ‘burn’ or
Various concepts have been proposed for deep deposition in reduce future wastes, the already existing, and most likely
salt, argillaceous and crystalline rock, but no large repository the future ones will require their disposal in deep cavities to
has yet been constructed. Many countries outside USA that avoid any contact with the biosphere.
focus on disposal of nuclear wastes are interested in the On the other side excavation of a large and suitable deep
design developed by the Swedish Nuclear Fuel and Waste cavern to house nuclear wastes presents great difficulties
Company based on tunnels at about 400 m depth with large- from the mechanical, environmental, geological, financial
diameter extending vertically from the tunnel. The plan is to and even psychological point of views. The unexpected, at
place the waste in shallow places for tens of years after least for me, failure of the Yucca project is a clear example.
extraction to reduce radioactivity and the consequence The efforts to investigate this problem and especially to
release of heat and then to encapsulate them in a 400–500 find suitable solution are at present in my opinion insuffi-
deep repository in rock (Pusch and Weston 2012). cient and require a further increased collaboration of

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geophysics with physics and other fields of science. This is New York Times (2011) GAO: Death of Yucca Mountain caused by
the message of nuclear energy to Anthropocene. political maneuvering
Ojovan MI, Lee WE (2005) An introduction to nuclear waste
immobilisation. Elsevier Science Publishers, Amsterdam. 315,
Open Access This article is distributed under the terms of the and references therein
Creative Commons Attribution License which permits any use, dis- Pusch R (1994) Waste disposal in rock, Dev Geotech Eng, Elsevier
tribution, and reproduction in any medium, provided the original Publisher Co. 76, 7 and references therein
author(s) and the source are credited. Pusch R (2008), Geological storage of radioactive waste, 978-3-540-
77332- Springer, Berlin, also for previous references]
Pusch R, Weston R (2012) Superior techniques for disposal of highly
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