By Dr Cathy Foley
The announcement by President Chirac that France will undertake a few quick nuclear weapon tests created a response in Australia that has taken many by surprise.
Since the end of the Cold War and the signing of the Strategic Arms Limitation Treaty, there has been a major drop-off in the membership of anti-nuclear groups such as my own. Most of those who moved away joined the environment movement, which has grown tremendously during the '90s.
Many believed that with the demise of the Soviet Union and the reduction of nuclear weapons, the world had immediately become safe from the nuclear threat. There have been few media reports on the insidious mini arms race that has continued since the Cold War in which the '80s trend of Mutually Assured Destruction (MAD) has moved to the design and testing of "mini-" or "micro-tactical" nuclear weapons, which the military believe can be added to conventional weapons arsenals.
As we have become sensitised to the concepts of the environment movement, we are well positioned to understand the implications of the resumption of nuclear weapons testing. The high level of media reporting on the nuclear testing at Moruroa atoll has also started to reveal a new nuclear arms race.
Why are the French testing nuclear weapons?
A series of 10-20 tests had been recommended by French weapons research scientists to obtain sufficient scientific data to check that nuclear weapons are robust enough to be maintained under a test ban.
The key issues that need to be addressed are production problems with bonding, mixing and plutonium metallurgy. This has resulted from the development of miniaturised warheads which, they claim, are more sensitive than US weapons. They need confirmation that the primary explosion (the first stage of the bomb which starts the nuclear chain reaction) will generate the thermodynamic conditions for successful boosting to the yield required to drive the secondary explosion, which is the main destructive process of the weapons.
Why test at all?
The design of nuclear weapons has always been primarily based on computations and computer simulations. These simulations are based on known laws of physics, but they make use of simplified physical models and approximations to describe a process too complex to allow precise description. These models contain adjustable parameters to obtain a best fit between computed and observed results in nuclear, hydronuclear and hydrodynamic tests (physical processes that create a nuclear explosion).
If nuclear tests could no longer be conducted under a Comprehensive Test Ban Treaty (CTBT), hydrodynamic and hydronuclear studies of the implosion phase of the primary (the initial ignition required to set off the nuclear chain reaction) could still be done and the information obtained used to extend and further improve the computer simulation of the primary implosions.
However, the experimental study of the boosting process, the primary explosion, energy transfer to the secondary, the secondary implosion and the secondary explosion could not be done. Experiments at the US National Ignition Facility (NIF) (a $1.2 billion facility built to continue weapons development in the US under a CTBT) would have only marginal, and possibly zero, value if ignition is not achieved, in improving the computer simulation of these aspects of thermonuclear weapons.
France can avail itself of experimental and test facilities comparable to those planned in the US if it wishes to do so, including the facilities of the NIF. French decision makers understand that large, expensive new facilities are not technically required to maintain the French nuclear weapon stockpile. Rather, they serve, along with more directly relevant computations, to maintain the interest and skills of a group of scientists whom France might call upon, at some future date, to resume the testing of thermonuclear weapons if future strategic developments should prompt French withdrawal from the CTBT.
Also, the French test moratorium decision by former president Mitterrand was made purely on political grounds to strengthen the non-proliferation regime. The chief of the armed forces did not know in advance about the moratorium initiative of April 1992, nor did the minister of defence.
How fragile is Moruroa atoll?
In 1988 France moved its testing from Moruroa to Fangataufa. Then, the state of Moruroa atoll was becoming dangerous and the cost of testing in the lagoon area too high. Every explosion produces a cavity and also shatters the rock for some distance around the cavity.
The exact extent of this shatter pattern depends upon both the size of the explosion and the nature of the rock. For a large-scale test, the shattered zone could easily be 400 metres or more in diameter. This indicates that the separation between test sites needs to be a minimum of 1 kilometre. Were the cavities to link together, and then link to the ocean, all the nuclear breakdown products would be released in a period of 1-2 years rather than the thousands of years presently assumed by French reports.
Most of the 123 tests have been conducted around the periphery of the atoll, which has a circumference of about 60 kilometres. Since there are to be further tests, the grounds for concern about the spacing between test sites is obvious.
The tests are conducted at a depth of 1000 metres. To ensure the necessary separation by operating at a different level, it would be necessary to sink the test shaft to almost twice the present depth, which is extremely expensive.
The radioactive waste which will eventually leak out will be diluted with a considerable volume of sea water. However, it will be reconcentrated, to some extent, by its passage through the food chain. Since fish are such a vital part of the diet and the economy of the local populations, if there is any substantial leakage, it will create a severe threat to the health of the native population.
Do underground tests crack the atoll?
In 1983, a team of six scientists visited Moruroa on behalf of the New Zealand, Australian and Papua New Guinean governments at the invitation of the French government. The purpose was to verify French statements that nuclear testing at Moruroa poses no threat to the integrity of the atoll or to the health of the South Pacific population.
The report stated that there were no significant atmospheric radiation levels and fallout. The structural integrity of Moruroa atoll had been impaired by nuclear testing in the coral limestone, but leakage from detonation chambers would take 500-1000 years. Venting of gaseous and volatile fission products does not occur at amounts which could be determined. Leaching from the underground test site could enable contaminated water to reach the biosphere in a time period greater than 500 years. Waste management, which was poor, is now very good.
The report was based on the idea that no more tests were to be carried out. Since then, tens of tests have occurred. The scientific team was greatly restricted in the measurements taken; for example, it was unable to collect samples from the lagoon or to inspect the fissures generated by testing.
Structural integrity of the explosion chambers is paramount to the containment of the water that flows into the cavities after the test. When the test explosion occurs, pressure and heat cause the volcanic material of the chamber casing to be vitrified or made glass-like. The concept is that the nuclear contaminant fallout materials from the nuclear test are constrained in this "glass" container.
However, computer simulations by New Zealand geophysicists have indicated that there would be cracks in this glass ball. This is quite a different scenario from that painted by Christian Lepareur, the French Atomic Energy Commission's technical director, who claims that there would only be hairline cracks radiating a dozen metres through the basalt layer and that there is no danger of radiation being released or of the rock cracking open.
What happens during a nuclear test?
A test shaft 1.5 metres in diameter, similar to an oil well, is drilled to a depth of 600-1000 metres. The measurement equipment in a 20-metre-long container is placed in the shaft and connected to computers which record the data as the test takes place. The parts of the test weapon are delivered by air to the area and assembled on site. The test piece is lowered into place by divers and connected by cable to the raised control platform from which the device is triggered. The shaft is sealed with a mixture of rock debris and cement designed to reduce the shock waves and prevent radioactive leaks.
Once detonated, the underground blast lasts for a few millionths of a second, causing a shock wave which makes the water in the lagoon heave and foam and is followed by a 15-second seismic wave. The enormous release of energy is recorded by the electronic equipment and the data are immediately relayed to recording computers before the equipment is destroyed by the blast. The data collected are of paramount importance to the weapons scientists.
The elevated platform, provided for the staff, is for safety in the event of the shock of the explosion causing unexpected waves to form.
What are the biological effects of the tests?
At the present time there is no real way of knowing the biological impact of underground testing, because there have been no independent measurements to assess the present state of the atoll and its surrounding area. Because atmospheric testing was undertaken in the region until 1974, it would be difficult to determine the contribution to any radioactive contamination by the underground testing.
The 1983 visit by independent scientists did not include a medical expert. It should be noted that the French National Radiation Laboratory has been strictly forbidden from making investigations in Polynesia. The only reports published are by army doctors who, from 1966 to 1974 in their annual reports to the UN Scientific Committee on the effects of the atomic radiation, never included the health statistics.
Up to 1983, the local health department, run by army doctors, refused to divulge any health figures. Death certificates are not required to show the disease which caused death. In 1983, under pressure from the World Health Organisation, a set of totally inadequate statistics was released. It showed only figures from the civilian hospital, whose staff consists mainly of army doctors. It excluded patients of the 80 private doctors, the military hospital and the numerous Polynesian healers.
No statistics have been presented of the many French Polynesians who have been treated for cancer in France. The repeated requests of the Territorial Assembly (the representatives of French Polynesia) for an independent commission of inquiry into the health statistics have been vetoed by France.
One measurable biological consequence of testing in French Polynesia is the increase in the occurrence of ciguatera poisoning. Ciguatera is a serious human intoxication that can result from eating certain species of tropical fish which live in reef waters. In the period 1960-1984, more than 24,000 patients were recorded having ciguatera intoxication from French Polynesia alone, which is more than six times the average for the Pacific as a whole.
The ciguatera organism grows on coral rubble and bushy seaweed substratum. It produces neurotoxins which concentrate through the food chain. It is possible to eat a small meal of contaminated fish without suffering immediate consequences, but subsequent contaminated fish meals, weeks later, can suddenly bring on neurological or gastro-intestinal disorders. Extreme cases lead to death. There is no anti-toxin or specific treatment.
Informed scientific opinion attributes the increase of ciguatera in the Pacific to the increasing disturbance of the coral reef environments, thus providing more substrate for the growth of the toxic organism. In addition to the destruction of reefs by cyclones and illegal dynamite fishing and tourist developments, increasing military activities in the Pacific Islands are also considered to be an important culprit. The sudden rise in fish toxicity on Hao atoll in the Tuamoto Islands, for example, clearly followed reef disturbance by the French Atomic Energy Commission (CEA).
Before 1964, there had never been any cases of ciguatera on Hao. In January 1965, the CEA began work to develop a staging base for its nuclear weapons testing program on Moruroa to the south. The work involved the beaching of landing craft from Tahiti and later included piers, dredging and other shore-side changes. The first toxic fish on Hao atoll was caught in August 1966 at the original French landing site. In subsequent years, ciguatera poisoning has reached 100 cases per month and has affected 43% of the 650 inhabitants. Similar effects have resulted from US tests in Micronesia.
What does this all mean?
French nuclear testing at Moruroa atoll will probably not cause that much more damage to the already environmentally destroyed atoll. These tests are much smaller in size than the previous ones (100 tonne equivalent TNT compared with 1 million tonne equivalent TNT), but there is always the danger that these tests may be "the straw that breaks the camel's back".
However, the resumption of French nuclear testing has raised other issues: France does not respect the sovereignty of the indigenous people to allow them to determine the use of their own lands; nuclear weapons are still being developed and these new "mini-" or "micro-nuclear weapons" are considered as useable weapons.
Furthermore, the Non-Proliferation Treaty which prevents non-nuclear weapon states from acquiring nuclear weapons is being jeopardised, since Article 6 requires the nuclear states to work towards the abolition of weapons. This round of testing proves that the nuclear states do not take this aspect of the treaty at all seriously.
[Dr Cathy Foley is the national president of Scientists for Global Responsibility.]