Since 1945, the nuclear powers have exploded more than 2,000 nuclear devices.50 years into the nuclear age, it seems we're finally coming to our senses. Next year the major nuclear powers look set to sign a treaty banning just about all nuclear testing. But before it signs, France insists on slipping in 8 more underground tests.
The French have exploded 175 in the Pacific.
The outrage at the French government's decision is universal: it's been decried as arrogant colonialism, jeopardising progress to a nuclear weapons-free world.
But there's also the strong belief that French nuclear tests have contaminated the Pacific and its people.
Given the litany of lies we've been told about nuclear tests - from the Marshall Islands to Maralinga - people are understandably sceptical of France's assurance that all is safe. Claims that France's testing has poisoned the environment and caused cancers and birth defects are of great concern, but must be viewed in the light of the available facts. Tonight, we weigh up the scientific evidence. Is radioactivity the real danger?
Radioactivity is something we all have to live with, all the time. Cosmic rays from space, traces of radioactive elements in soil and our food; they make up what's called natural or background radioactivity. For Australia and South Pacific nations that's measured as 2 MilliSieverts a year.
To put that in perspective: every time you have a medical procedure like a CAT scan or barium meal, you're exposed to about 4 times that radioactivity, up to 8mS.
Most experts agree the 2 mS background radiation does us little or no harm. But when it comes to additional radioactivity: the less you're exposed to, the better.
In March 1954 the United States exploded a 15 megaton bomb on Bikini Atoll. People on some nearby Marshall Islands received a tragically high dose of radioactivity, with tragically clear results: thyroid disease and cancers, for which the United States belatedly paid compensation.
We know from the survivors of the first nuclear weapons at Hiroshima and Nagasaki that doses of radioactivity above around 500 mS do cause extra cancers and birth defects in a population. The Marshall Islanders were exposed to four times that level, nearly 2,000mS. The case is not so clear cut in French Polynesia.
Between 1966 and 1974, France exploded 41 atmospheric tests in French Polynesia. The total yield was 15 megatons equal to one US test on Bikini atoll.
Dr Murray Matthews "Our estimate is that on average in the Pacific Islands from the entire history of atmospheric weapons tests individuals in the islands would have received around about one miliSievert over their entire life times from that testing."
National Radiation Lab New Zealand.
One mS spread over 50 years. How can we be sure the exposure was so low? The figures come from the Australian Radiation Lab and the National Radiation Lab in NZ. Both exist to monitor radiation hazards and protect the populations. The labs have no vested interest in the nuclear industry - NZ doesn't even have a nuclear reactor.
During the whole period of French atmospheric testing New Zealand monitored the levels of fallout at their network of South Pacific stations.
The fallout was low, but uneven. There were rainouts, times when winds blew a cloud of radioactivity over island populations. If it rained, fallout rained down too.
Q. So that's still a tenth of the background radiation?Dr Murray Matthews National Radiation Lab New Zealand. "The most significant event occurred in 1966 when there was what we call a blow back from Mururoa towards Samoa in particular where the from the test went westward instead of eastward and it was caught in a heavy rain event at Samoa and this resulted in quite a lot of local contamination even then though the dose in that year from that event would have only been around naught point two miliSieverts.
A. 1/10 of the annual background."
There was another rainout in Tahiti in 1974, but again fallout was well below background. We know of one other rainout, in the Gambier Islands, just to the southeast of Mururoa. Fallout was higher, 4 mS, twice background radiation, but many hundreds of times lower than Marshall islands. Now, some of these figures do come from France's monitoring stations, but they closely correspond to the levels and patterns of fallout monitored by New Zealand.
Dr Andrew McEwan "The radiation doses were so low that no effects from radiation would be expected. If there is no radiation there can be no radiation effects."
National Radiation Lab, New Zealand
So what are we to make of the worrying claims that birth defects and cancer rates have increased in French Polynesia since the tests? As harsh as it may seem, reports of an increase of birth defects are all anecdotal - there simply isn't a register of birth defects in French Polynesia. And while evidence is building that cancers are increasing, there are other explanations.
Dr Andrew McEwan "Increasing cancers will rise if the people live longer, if the life expectancy goes up then the cancer rates go up because cancer rates increase with age. Another cause of increased cancer is changes and life style factors such as increases in smoking and if the population is smoking heavily then there will be a very considerable rise in lung cancers and other cancers."
National Radiation Lab, New Zealand
Mururoa is a seamount- formed more than 7 million years ago when a volcano erupted beneath the sea. When lava hits cold water it forms intertwining tubes of rock, which build up a mountain.
The mountain erodes leaving a basalt base and a middle layer of soil. The top layer of limestones and corals leaks like a sieve.
Prof Michael Michael O'Sullivan "There's a very permeable zone from the level where the arrow at about 400 hundred meters below sea level up to the surface and that consists of limestones which are naturally very permeable and very leaky and the heavy ocean water here drives the water through the atoll up into the lagoon."
University of Auckland
Any nuclear waste would get through these middle and top layers very quickly. But the shafts for the underground tests are up to 1,000 metres deep in the basalt base, supposedly well clear of the leaky layers.
Megan James "What happens when you add a nuclear explosion or two according to the French?"
Prof Michael Michael O'Sullivan "Well we detonate a bomb//down in these deep basalts and then what the French claim is this kind of scenario where we have a chamber here which consists of glassified rock which is broken up in little lumps and surrounding that they say the rock is not very badly effected. So the natural flow of water is virtually unaffected by the bomb going off and radioactivity is safe down in the volcanic rock."
University of Auckland
But there's a problem. The French claim the chamber is sealed, yet cools quickly. The only way it could cool quickly is if the chamber is really so cracked it allows cooling water to get in and out.
Prof Michael Michael O'Sullivan, "Now we have a large fractured chamber// Then the water can get down into the bomb site and up again."
University of Auckland
Professor O'Sullivan concludes radioactivity must, in time, leak out. Is it leaking now?
The latest evidence we can now reveal strongly supports France's claim underground testing has not poisoned the marine environment.
These are samples of foodstuffs collected on Mururoa by the International Atomic Energy Agency. Fish from the lagoon, spiny lobster, molluscs and coconut milk.
The Australian Radiation Laboratory was one of 8 around the world given samples of the same organisms collected at the same time. The analysis shows there is radioactivity in the samples, but the levels are very low.
The results are credible because all 8 labs concur. Among them was New Zealand's National Radiation Laboratory.
Dr Andrew McEwan "The levels in those fish did show traces of Caesium 137 and strontium 90 which one would expect and the levels were fairly consistent with what one would expect from global fallout but there is certainly no evidence of significant leakage of any type."
National Radiation Lab, New Zealand
Mururoa may not be leaking now, yet even the French admit the radioactive waste stored under their feet will eventually escape. But they say it won't be for thousands, perhaps 10,000 years.
The French claim the basalt that forms the base of Mururoa is not very porous; so any water in the blast chambers will take thousands of years to move through the rock. But there's good evidence it will happen much more quickly than that.
Megan James "So these are actually samples from Mururoa itself?"
Prof Peter Davies "That's correct."
University of Sydney
Professor Peter Davies visited Mururoa in the early 80s. He studied just how porous the atoll's base is. Some parts are far leakier than others.
Prof Peter Davies "If you look at this sample for example there are nicks and cracks through the sample indicating that there are fisures which run through the sample and that is very important in terms of the conactivity of the pores in other words how water will transport through the rock."
Megan James "And from the variety of porosities that you're looking at here how did you redo the sums on the how long it would take for leakage to occur from these basalt chambers?"
Prof Peter Davies "From that I calculated best case scenarios of greater than 500 years for leakage fluids from the middle of the atoll."
Megan James "And a worst case scenario?"
Prof Peter Davies "Well the worst case scenario is related to something happening associated with the test and that's almost instantaneous."
And accidents have happened. In July 1979, a 120 kiloton bomb got stuck halfway down the shaft, at 400 metres. They exploded it anyway, and because tests were then on the rim of the atoll, part of the southern side collapsed in an underwater landslide.
Prof Peter Davies "The French have admitted to some million cubic meters of rock having come away from the side of the atoll. Well a million cubic meters is substantial however think of what it means: it's a hundred meters by a hundred meters by a hundred meters// that is actually a small portion of the atoll but nevertheless// they've also moved their tests back into the lagoon. And I don't think that they have reported or anybody has reported land slides since."
University of Sydney
Because the tests are now in the centre of the atoll, and the bombs are now smaller, the risk of a major collapes is very low. Long term leakage remains by far the most realistic scenario.
Prof Peter Davies "In 500 years or whatever it is and I don't know what the exact time is but at whatever time, there will be the potential for Mururoa to leak radionuclides into the biosphere."
University of Sydney
But such leakage may not be as dangerous as we've been lead to believe.
Dr Murray Matthews "Well a key factor which seems to be overlooked in most people's arguments is just what the source term is, how much radioactivity is locked up in Mururoa after all of these tests, it seems that in many circles some people think a very large amount of radioactivity is there and it should be called into perspective how much is there. "
National Radiation Lab New Zealand.
The total fallout from all atmospheric tests ever conducted is 300 megatons. The total of France's underground tests to date is just under 3 megatons. We know that from New Zealand's seismic monitoring stations.
Most of that 3 megatons is locked in the glassy lining of the cavity created by the explosion. Only around 5% is loose in the blast chamber.Let's imagine for a moment that somehow it all leaked out tomorrow. Incredible as it may seem, the sums done by NZ's radiation scientists suggest there'd be no great danger to environment or health.
Dr Murray Matthews "Well most of our reasoning in this area is based on recommendations of the International Commission on radiological protection and that body produces recommendations for limits of intake - they call annual limits of intake and if all of the material presently in Mururoa were to dissolve in a lagoon that size if it were fresh water, one could drink around about 300 litres of that before one would reach the annual limit of intake".
National Radiation Lab New Zealand
Megan James "What about in a couple of hundred years, which is the best estimate, what would be the danger then?"
Dr Andrew McEwan "Well if one goes to hundreds of years to the future, then the fission products of more particular concern like caesium 137, strontium, they have halflives of 30yrs, so going 90 years is going through three half lives that the total amount is down to 1/8th - go another 90 yrs it is down to a 64th so it is actually decaying away and if you go hundreds of years into the future then you probably haven't got a lot of radioactivity to worry about."
National Radiation Lab, New Zealand
None of these scientists is saying that Mururoa is contamination-free. It's known that in 1981 a typhoon washed between 10-20 kgms of plutonium, the legacy of earlier weapons safety tests, into the lagoon. Plutonium, when it's in the air and can be inhaled, is one of the deadlies substances we know. But in a marine environment like the lagoon, plutonium gets very strongly bound up in sediments, very little gets into the food chain. (as confirmed by the latest IAEA study.)
Megan James: A lot of people might interpret this information as scientists saying that the testing is ok. That it can go ahead?
Dr Murray Matthews "Well there are two distinct sets of issues related to Mururoa as the public see it. There are the what I would call political philosophical issues of whether we want weapons to be developed, whether we want nuclear proliferation, whether we want more people with nuclear weapons on the planet, there are those political and philosophical issues and then there are the environmental ones which I have been talking about. All I'm saying is that the environmental issues are not as great as people will appear to think they are".
National Radiation Lab New Zealand
Prof Peter Davies "The French are their own worst enemy. I think they have a huge data base which if shared properly with the scientific community would help to dispell many many of the problems that people currently relate to what is happening at Mururoa because on the basis of easily verifiable experiments it would be possible to show that much of the French data is correct. But they label everything confidential and therefore it never sees the light of day- it does them no good at all I said this to them in 1984."
University of Sydney
The weight of scientific evidence is that the test pose no great danger to human health or the environment of the region. The real danger is that France's and China's resumption of testing may derail progress to a world free of nuclear weapons.
Dr Karin von Strokirch "Well President Chirac gave the most detailed statement about the purpose of the nuclear tests one month after his announcement of test resumption. He explained to the French senate in Paris that of the eight tests four would be used to perfect computer simulation of nuclear tests two would be used to test the reliability and effectiveness of ageing detonators and fuses and the remainder, that is to say two, would be used to test what he called a new war head."
Australian National University
That new warhead may be TN75, the TN100 or a new generation variable yield warhead: potential first strike weapons.
Many of the new generation nuclear warheads are small enough for their testing to be hidden.
Dr Peter Wills "The thing that really makes me suspicious is that the military the French military wanted to to conduct 20 tests they said before France signed the comprehensive test ban now that makes me wonder if the eight tests which have announced involve something of the order of 20 devices rather than just eight as you would have thought."
Greenpeace Spokesperson
Dr Karin von Strokirch "Well I believe that in the past the United States has conducted two nuclear weapons test explosion simultaneously, there's no reason to believe that France can't do that."
Australian National University
If the French do test 2 devices simultaneously, we won't know. The Seimological Centre in Canberra will be the first place in Australia to detect any explosion. But from this distance, they can't identify an explosion under 1 kt, if masked by a larger one.
Dr Peter Wills "In the broader picture in the long run the reason to have a comprehensive test ban and to stop testing is to inhibit the development of nuclear weapons and the great offence which France is causing at the moment is that they say they will sign the comprehensive test ban when they have developed the means for circumventing it."
Greenpeace Spokesperson
Those means are computers. France needs the field data from the Mururoa tests to perfect its computer simulation programs. But even if we stopped the French tests, other nuclear nations could continue the electronic version of the arms race. Because even under the proposed treaty banning all field tests, nuclear weapons are allwed to be developed and refined, via computers.
We've directed all our protest efforts at trying to stop this series of French tests, as though stopping them would somehow stop the arms race. Perhaps our protests would be better directed at ensuring next year's treaty is comprehensive in its truest sense.
Dr Karin von Strokirch "No nuclear tests full stop no simulation full stop don't allow it nothing nothing is going to be allowed that will help a nation to develop nuclear weapons. "
Australian National University
"The opportunity we have now for achieving a comprehensive test ban is greater than it's been at any time since nuclear weapons have been invented//And the danger is if we don't achieve a ban within the coming year the political situation could change in any one of the main players' countries. For example the United States is having presidential elections Russia is looking towards presidential elections the Chinese paramount leader may die in the not too distant future and if the political context changes in one of the nuclear weapons states it may change the whole of the nature of the negotiations for a comprehensive test ban".
Megan James "We would have lost that opportunity?"
Dr Karin von Strokirch "Mmm this is a window of opportunity now and we need to take it while its there."
Australian National University
This program was produced by Quantum and 1st screened on August 23 1995
It was written and reported by Megan James.
Copyright Australian Broadcasting Corporation 1995.