"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)