"SOME PHYSICAL AND ENGINEERINGIMPLICATIONS OF NUCLEAR EXPLOSIVES"
by
Brian J, O'Brien
Chairman, Environmontal Protection Authorityand Director of Environmental Protoction
1 Mount Street, Forth, W.A. 6000
August, 1973
Paper dolivorad «t ANZA/VS"Tlie Implications of Nuolaar Kxploaiv*aM
45th ANZAAS Congress PerthAugust 13-17. 1973
INTRODUCTION
The title of this Symposium "The Implications
of Nuclear Explosives1* rather than "Nuclear Explosions"
gives me the opportunity to draw on experience of
the past as well as speculate on the future*
Nuclear explosives oan, of course, bo ua«d
for purposes either peaceful or nan-peuoeful (albeit
generally as a so-called "nuclear deterrent"). Gomo-
tlmets these Interests partially overlap, off where
a high-altitude nuclear explosion might provide to
military personnel valuable data on lonosphorio
interference of missile tracking and provide also
data of a "controlled" experiment category to scientists.
I will concentrate in my introductory comments on
"peaceful" aspects, with some historic background
information.
i note also that with the particular interests
and expertise of the following jpeakern, Professor
Titter ton and Dean Hasselwood, I will initially oonfino
my comments to a few general comtnonta on soiontifio
and technological aspects, rather than biotnedioal,
moral or political matters.
CATEGORIES OF PEACEFULUSES OF NUCL12AH EXPLOSIVES
Nuclear explosives can be used "poacefUlly"
In the following; regions:
1) Outer—space - above say ̂ R (25,0001cm)
2) Upper Atmosphere - above say 30km (io rocket-borne)
3) Atmosphere - above ground but below 30kin
(ie balloon-borne or by aircraftdrop)
k) Surface or near-surface - to produce cavities
open to the atmosphere
and
5) Deep sub-surface - to produce undergroundcavities
3. • \
POTENTIAL USES OF JIUCLi;:.Vtt liil'i.O3XVBP
iPotential uses of nuclear explosives in Category 1, j
(outer-space) would be those associated with, say,
aelenological studies (eg creating cavities in the
Slide 1 moon's surface), studies and/or calibration of celestial j
sources of X-rays, and no doubt other exotic experl- j
ments. X know of no serious suggestion that outer- !
space nuclear explosions should take place, and !
certainly from the point of view of them contaminating \
the little-known outer-space environment X would f
bo vigorously opposed to such experiments. I
CatoKory 3 jUpper atmosphere tests (> 30km altitude }/lu7vo j
been carried out by the USA and the USSU, principally |
in 1958 and 1962. There is little point in listing jj
these explosions here, but X do vish. to comment on j
one of them specifically later insofar as it la of i
relevance to the total issue. X refer to the July 9, j
1962 "Starfish" explosion of 1,40O,O0G tons (1 »k MT) \
of TNT equivalent.' • '
Category 3 (atmospheric) tests such as thoeo
recently carried out by the French and Chinese,
scarcely enter the realm of poaceful uses. In fnot,
us long as they aro carried out below say 30km altitude,
any potentially interesting scientific "spin-off11
suoh as studies of X-rays, artificial auroras, artificial
radiation zones etc. is negligible. There may be
some scientific interest in atmospheric and meteorological
effects, both short-term and long-term but I have no
relevant data on such aspects.
Category h explosions, those which create [
cavities open to the atmosphere aro of considerable
interest to many. It has been proposed that they
could be used to make harbours, canals, dams and the
like, and X will discuss some aspect a in detail
particularly as they might pertain to Western Australia,
k.
Category 5 explosions, creating underground
cavities, have been the subject of much study, eg in
tho USA in Project Gasbuggy. w / Th«» object of such
an exorcise was to significantly increase the recovery
of natural gas. For example, in the first Gnsbuggy
detonation on December 10, 19<>7» & 26 klloton explosion
was triggered at n depth of 1,292 meters in a low
permeability natural gas reservoir.
Other usea claimed for Category 5 cavities
(eg Figure 2 of Project Gnome) are for stimulation
of natural gas and oil reservoirs, storage of natural
gas and liquid hydrocarbons, water storage and waste
disposal.
Probably the most publicly controvaralal of
all those categories of nuclear explosions is that
of Category 3 - explosions in tho lower atmoaphoro.
These were included in the August 1963 Partial Nuclear
Test Ban Treaty, to which Australia and some 105
other countries are signatories. I expect this
category to receive moat attention during tho lator
sessions, and therefore now I will oonfine remarks
to Categories 2 and 4 - explosives in the upper
atmosphere and those that produce open cavitiea in
the ground.
NUCLE\R EXPLOSIONS
My first detailed professional atudy of nuclear i
explosives was in 1962* In particular on July 9th 1
at 0300 hours GMT, the United States exploded a |
1.4 megaton nuclear device at an altitude of 250 •
miles above Johnston Island in the Pacific. There .1
had been strong criticism of the proposal to carry j.t
out such a large high-altitude test because somo ]
considered that i t was not known for certain what |
the consequences would be. Some experts in the U.S. J1
who had been involved in the earlier 1958 upper |atmosphere tests , which were conduoted with bombs j
i
at lower altitudes, predicted that there would notbe any particular significant problem which would
be so great as to adequately argue against the Pentagon
proposal to carry out the test in America's other
interests.
My involvement with the results of this test
came about because I was Scientist and 12ngineor in
charge of the satellite, Injun 1, launched on Juno 29»
19^1 from the U.S. This was a completely nonclasslfied
satellite and was designed to study ionizing radiation
such as in the Van Allen zones and in tho aurora and
polar regions and also to study the optical emissions
from airglow and aurora.
Injun 1 therefore had mapped out the radiation
around the earth for rather more than a year before
the test and had produced the most definitive map
of radiation levels at roughly a thousand kilomotrea
than had ever been produced at that date. In other
words we knew what the natural levels of radiation
wore.
I was interested as a scientist, of course,
in what radiation levels would result at such an
altitude following the Starfish explosion and I was
very carefully nursing the satellite along (since
6.
it was gettine old for that time) so that it would
still be operational at the time tha dovlco finally
was detonated.
There were some three to four months of false
alarms before a missile took Starfish to the 250 mile
altitude and it was detonated. The test was timed
so that there would be no satellites directly above
it or in the near proximity, and in fact Injun 1
at the time was approaching: the coast of North
America. However, by the time the satellite, travel-
ling at some five miles per second, had reached
South Africa a band of such intense radiation enveloped
it that the geicercounters were saturated. (Figure 3) i
This belt of radiation, artificially produced,
was dominantly fission electrons of energies of
several MEV and therefore very penetrating. The
increase in radiation level is illustrated by tho
accompanying elides and it will be neon that it vrae
some 10,000 times more intense than natural radiation I
at an altitude of 1 ,000 kilometres over tho U.S. (figure
The magnitude of the explosion can be gauged by tho
accompanying two slides (Figures 5 and 6) which show
the artificial aurorae that were caused in the vicinity
of Johnston Island. The ionising radiation produced
corresponding aurorae at the other end of the magnetic
field lines in the southern hemisphere. For interest
I show in the next slide (Figure 7) a photograph of
a naturally produced aurora, which WAS produced in
the Arctic by low energy electrons*
During the following months we analyse* the
Injun 1 data and were able to see the rate at which
the radiation belt slowly faded away.
As it turned out because the Injun operation had •
already been going for over a year we had a very
efficient data classification and analysis technique
worked out and consequently within three woeks after
the blast I was able to write a scientific report
on the now artificial radiation *'
Shortly thereafter the National Aeronautics
and Space Administration experts were analysing why
their satellites, Transit 4A, Traac and tL\e joint
US/lJK Ariel 1, were not working too well. The total
cost of the satellites, of course, plus thai? rockets
was several tens of millions of (US) dollars.
Once we put together the radiation data that
Injun 1 hud oollootod and on analysis was made of
solar-coll deterioration under radiation it was found
that tha Starfish ./ 'Vad^offeotively lowered tho
power capability of each satellito to tho point of
being virtually non-operable.
It is a rather amusing ironic fact that Xhjun 1
continued to operate during this period and that
there was a simple explanation for this. The other
satellites which had gone non-operational were using
very high efficiency solar-cells of some 12 to 13
per cent which are very readily degraded by radiation.
Injun 1 on the other hand wus using, because of tho
amall budget with which X was working, 5 to f> por
cent efficiency solar-cells which vroro essentially
rejects and so degraded that they could not deffrcu*
any morel
The message, therefore, of Starfish really is
"don't use nuclear explosives unless you know what
they are going to do"t Starfish effectively blew .
the top off the atmosphere over Johnston Island and
sent ionizing radiation out some 10,000 miles whero
it became trapped in a radiation belt and was partly
a hazard and certainly a nuisance for those who wero
trying to explore the natural environment at high
altitude.*2'
I wish to comment briefly on the scientific
potential of high-altitude nuclear explosions*
The 1953 Argus series and the 1962 Pishbowl
series of US tests (including Starfish) were con-
ducted by US defence agencies. Nevertheless, a con-
aiderable amount of "pure" scientific information
flowed from them.
From Argus came thin shells of fission electrons
enveloping the earth, and from Explorer XV studies
came proof and validation of Mcllwains model * ' of
the geomagnetic field and the motion of charged
particles trapped therein.
From Sturfieh came artificial auroraa, ploama i
studies**-' and an understanding of the natural rata §
of loss of trapped particles. Knowing cmoh loaa \i
rates, one can investigate what the previously unknown !
source rate and hence what the unknown source o£ \
Van Allen radiation might be. ji
Another potential use of high-altitude nuclear- ;
explosives has been discussed for at least a decade, i
We know that the solar wind distorts the geomagnetic :
field, compressing it on the sunwards side and extend-
ing it in a long comet-like tall on the night* *' oido.
The geomorphology is extremely oomplex, and much of ;
the ultimate understanding of oolar-torrontriaJ. i
relationships is hidden due to our incomplete Icnowletl&o
of the geomagnetic configuration. j' ' ' • i
Xt has therefore been suggested that a seriee ;
of say 1 KT nuclear devices exploded at various j
meridians and at latitude intervals above aay J\ « *5 |
could resolve these problems. From a simplistic ' |
view, one could study conjugate points and determines '•?
which magnetic field lines are "open* and which are I
•closed1. • I'I
' " . • • !
However, no substantive proposal of such a 1
project has been put forward because of the 1963
Partial Nuclear Tost Dan Treaty,
9.
EXCAVATION BY NUCLEAR DEVICES
Peaceful uses of nuclear explosives which have
been given most attention art those associated in
one way or another with underground explosions. Tho
underground explosions might be treated as in the
case of Gasbuggy's towards liberating large amount is
of gas for peaceful u«ea, or again nuclear dovloon
might be utilised to carry out excavations for such
purposes as the creation of a dam or the creation
of an artificial harbour and the like.
In various countrias of the world much work
has been carried, out (some of which is not available
to the general public) on the development of such
techniques. The prospect of widely publicised explos-
ions of this type has aroused considerable concern
from some conservationists oa witnessed with the
Amchitka Island Alaska explosion which raised a storm
of controversy in the US to the extent that legal
arguments went as far as the US Court of Appeal.
Tho Amchitka explonion was approximately 5 NT,
detonated about a mile bolow the Ground in November
1971* It produced prompt earth tremors ranging between
6.8 and 7.5 on the Richter scale. When the hot gases
cooled, there was an earth slump same 38 hours after
the explosion, and this slump caused a Richter reading
of 5.
The only reports I have at hand on environmental
damage to fauna listed a few hundred dead fish,
18 sea otters, four seal, and 15 birds, Seme two
weeks after the explosion it was reported that the
beach and ocean floor in the vicinity appeared to
have been lifted permanently by several feet* ,
However, these are largely press roports and
doubtless others here have more reliable scientifio
reportB which they may wish to discuss.
10.
The Amchitka test was not directed at creating
a crater but rather at testing the Spartan ABM warhead a
In the general context of ABM's, ICDM's, MIRV( 5)
etc. I refer you to the review by York. '
Unfortunatalyt tho taulutioal information 1
have at hand on such tests is roetrioted to US tusta
up to about two years ago. I am given to understand
that there has been considerable work in the USSR
but I do not have reliable data here.
As mentioned, T will concentrate on aspects
euch as harbour making, canal excavation and creation
of dams and the like.
Such studies began with the first thermonuclear
or fusion oxploalon of 10 N T in the Euiu-o* ok atoll,
in 1952. The crator produced wua about 1700 miitqro
wide and 50m deep. The estimated eartu-movisifi oootn
were calculated to be only a few cents per cubic
meter.
Project Plowshare vas established at 1 ivermore
(Lawrence Radiation Laboratory, University of California)
in 1957* Since then, several hundred underground
tests have been carried out, with about 150 during
the period 1958-1961 alone.
Clearly therefore, a great deal of technical
information has been acquired, and there is no
possibility of adequately covering all these findings
hare.
In December, 1961 the Gnome explosion of J,h K T
at a depth of 365m in bedded salt at Carlsbud produced
a cavity (Figure 2 ) about 50m in diameter and 21m high.
In 19^2 Project Sedan (Figure 8 ) was carried
out. A 100 K T nuclear device wae exploded at a depth
of almost 200m. The resultant crater was about 100m
deep with an average diameter of about 400m. It is
I I
stated that less than 30$ of the energy was from
fission and less than 10$ of the total radioactivity
was rolonsed us prompt fallout*
A contrast to the single-shot Sedan experiment
was tho March 12, 1968 Buggy experiment (Figure 9).
In Ruggy flvo 1 KT nuclear explosives wore fired
simultaneously to form a ditch 2km <£at»p, some 275m
long and about 90ra wide.
In studies of canal construction or harbour
construction (Figure 10), studies need to be made
of geological structures and the like, but in general
the multiple rather than aingle-shot techniques seem
to be preferred.
In such excavations nuclear explosives possess
two very significant advantages over chemical (con-
ventional) explosives.
Hie firat advantage of the nuclear oxplouivo
io its concentration of tremendous energy in a small
volume. The largest chemical charges over detonated
are of the order of a few kilotons because of the
practical limitations imposed by weight and size.
A chemical explosive has approximately the density
of water and a yield of one kiloton, or 1,000 tons
of TNT, represents a volume of 1 ,000 cubic moters
(35»OOO cubic feot). By contrast, nuclear explosives
with yields up to 100 kilotona can be designed for
cylindrical cannisters 28cm (11 inches) in diameter
and about 5m (15 feet) long,
Tho second advantage of nuclear devices is
their relatively low cost. (Figure 11)
Consequently many projects which could not
even be considered because' of cost and size limitations
of chemical explosives could become practicable
through use of nuclear techniques.
12.
However, I now wish to explore not 90 much as
to whether they are practicable but whether they are
desirable or acceptable.
13.
ASPECTS OP EXCAVATION BYNUCLEAR DEVICES
Tho engineering economioo of the use of nuclo&r
devicer for excavations has been mentioned. Disadvantages
In the public view include:
1) stray or residual radioactivity j
2) potential shock effects - whether in water ;
or on land j
3) air shock, including focussing by atmospheric \i!
refraction S
'0 residual seismic instability !
3) effoots on local hydrology j
6) effects on local fauna particulurly fisheries !
resources* '!
To discuss these in detail one has to take a
particular example, with prior geological, hydrological
and other surveys for the site in question. Such an
examination is beyond the scope of this paper.
However, in reviewing the litorature, many studied*"1*
stress the desire to go forward with these projects
not so much because of their direct benefit to mankind,
but because they will fvive a (treat deal of new eHifjinaQE*-
ing information with which future projects con bo
undertaken — in other words, they ara largely oxpMericneatal.
To quote from Toman*5' "it would appear that
construction of a relatively low-cost harbour (lass
than $20 million) would be a reasonable first step
in demonstrating the usefulness of nuclear excavation |
as an engineering tool. The tremendous amount of
information that would be obtained is direotly applies- |
able to much larger projects, such as an interocoanic 'i
canal, and would provide a real basis for comparing If
conventional versus nuclear excavation.n - referring
to the Cape Keraudren project.
A similar uncertainty apparently surrounded
the Amchitka test, as regards to whether a crater
would develop. I have only press reports, but according
to them 20 hours after the event, when the "expected11
crater had not formed, a press statement by an AEC
spokesman, Mr, David Jackson, was as follows:
"It may be a matter of days - or it may not even )
occur." 1I
However, when the crater was apparently formed \
at T + 38 hours, it was claimed that the settling i
occurred as expected, i
The paradox confronting us therefore in Australia '/
is whether, noting the economics involved in, for ]
example creating large harbours with such devices, ;I
but noting also all their largely experimental and !hence uncertain consequences, one should allow j
Australia to be used as a testing ground. Although ii
the study of the art has significantly advanced i
since the Starfish explosion in 1962 I must admit '
that personally I take the conservative view that
at this point in time such explosions should not
be encouraged. X well remember the British Prime
Minister, Winston Churchill, on the occasion of
previous activities relating to the use of nuoloar
devices in the vicinity of the Hikini atoll saying
that he must remind his American colleagues that
the Pacific is not an American Lake.
In summary, with Starfish, the engineering
reports and Amchitka, the scale of the projects and
their complexity is such that the outcome is not fully
predictable. In such cases, in the end, the decision
to go ahead with a project is a political one, as
it was with Starfish, and as it was with Amchitka.
And as soon as this element is introduced, one ha©
tu oonsidor what mny bo called a Nbonofit-risk
1is
i
15.
BENEFIT RISK ANALYSIS
In his paper entitled "A Suggested Guideline
for Low Dose Radiation Exposure to Populations Based
on Benefit Risk Analysis" Jerry Cohen from the Lawrence
Radiation Laboratory of the University of California.(a)
providedv/ some interesting comments. He stated that
for the USA current standards for allowable exposure
of general population to ionizing radiation proscribed
at a minimum exposure of 500 milligram per year to
Individual** and an avnrage exposure of 170 milligram
per your to on it ably asuossod groups. Thosn Mton<lux*de)
as sot by the International Commission on Ktull a Ionian!,
Protection (iCRP), the US National Council on Radiation
Protection (NCRP), and the US Federal Radiation Council
(FUC) he says are generally accompanied by such admoni-.
tions as, and he quotes from NRCi', 1 "it is recommended
that all doses be kept as low as practical and that
any unnecessary exposure be avoided", and from FRCP
reference 2, "it is critical that this could bo applied
with reason and judgement". As I understand it tho
170 milligram per year standard 1» the moat
usid us a basin for comparison with ronotor
studies or plough-share of fact •val\u\tioiiHe
rationale Dr. Cohen goes on to consider.
The relevant point here from his discussionp
however is that instead of using qualitative emotivo
terms such as radiation doses to be "as low as
practicable" he wants a quantitative definitive
guideline as to what is acceptable or not from a
total viewpoint, ie from economics savings benefit
of a new harbour not otherwise practical and so onp
ae woll as any potential disadvantage a duo to radio-
activity and other factors listed above.
Now to carry out such a study one is confronted
very quickly with the problemt how many dollars in
a human life worth?
16.
Cohen' ' did not hesitate. He puts a value of
8250,000 on a human life, and as he comments, others
have found this morally objectionable but still others
have devised similar estimates.
*7'Cohon devised a unit called the "Her" and
elaborated on it. One Mer is defined as the amount
of benefit required to Justify an exposure to one
rein of radiation. At first it was proposed "tongue-
in-cheek" but later it was developed by Cohen and
others.
Figure 12 shows some Her equivalents for the
USA. Cohen' ' lists other authors aa indicating,
in place of his £250,000 values of $250,000, $100,000,
810,000, S200 and $100.
I might add that In a quick independent survey
of my staff last week X was given estimates of the
worth of a human life as:
$100,000 (three times)
$150,000
§50,000
$3O,000
$3«000 (she had a migraine headache at the time)
and $2,000 (she was typing my ANZAAS manuscripts
at the time).
Clearly, however, this is where th«* importance
of nuclear explosives moves outside the immediate
professional field of the environmentalist and into
the moral and political fields, which no doubt will
be discussed later.
REFERENCES
1. O'Brien, B.J., Laughlin, CD., and Van Allen, J.A.
Nature, Vol.195, 939, 1962
a. Proceedings of a Conference on the Artificial
Radiation Belt of July 9, 1972, Journal of
Geophysical Research, Vol,65t February 1,
3. Goonuclear Nobol i'uso Haport "A New Conoopt
in LDxplosivas
'••. O'Brien, B.J., "Interrelations of Enargotic
Charged Particles in the Magnetosphere" Chapter 6
Solar-Terrestrial Physics, Academic Press Inc.
London, 1968
5. York, H.F., "ABM, MIRV and the Arras Race"
Science, i6£, 257, July, 1970
3. Toman, J., "Summary of Nuclear Excavation
Applications" Lawrence Radiation Laboratory,
University of California, Livennoro, 1970
7. Nordyke, Milo I). , "Underground Engineering
Applications - Concepts and Experionoo"
Lawrence Radiation Laboratory, University of
California, Livermore, 1971
8. Kncx, Joseph B., Tewas, Howard A. t Crawford,
Todd V., Gibson Jr, Thomas A., "Radioactivity
Feleaaed from Underground Nuclear Detonations:
Source, Transport, Diffusion, and Deposition"
Lawrence Radiation Laboratory, University of
California, Hvonnoro, March 2, 1970
9. Cohen, Jerry J., "A Suggested Guidollue for
Low-Dose Radiation Exposure to Populations
Based on Benefit-Iliak Analysis11 Lawrence
Radiation Laboratory, University of California,
Livermore, June 1971
FIGURE CAPTIONS
Figure 1 : Table 1 - Regions of Use of Nuclear Explosives
Figure 2: Project Gnome (3kt at 365m)
Figure 3: Comparison radiation intensity over South
Africa before Starfish and at x + k5 minutes
Figuro hi Comparison altitude profilo of radiation
before and after stnrfiau
Figure 5: Artificial aurora over Johnston Island
caused by Starfish, verticle scale 3»000
kilometres
Figure 6: Artificial aurora over Johnston Island
caused by the shock wave from the blast
Figure 7: Naturally produced aurora over the Arctic
Figure 8: Project Sedan - crater resulting from
the 100 kiloton nuclear dovico
Figure 9: Ditch created by 1968 Buggy experiment
of 5 1 kiloton nuclear explosive Tired
simultaneously
Figure 10: Diagramatic illustration of a deop harhouK1
which could be produced by nuclear explosives
Figure 11 : Comparative costs of nuclear devices of
various yields versus conventional explosives
Figure 12: Suggested "Mer" equivalence for the USA
(from Cohen reference 9)
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