Atomic Thunder

by Elizabeth Tynan

  They slog through this routine for six days without incident and all seems well. The Pearce Report seems more or less to reflect the reality on the ground, with only a few anomalies or hotspots. But on Sunday things start to get strange. If ever the biblical commandment for a day of rest made sense, it is after spending a long, hot, dusty week routinely walking backwards and forwards slowly covering a large swathe of the vast testing site. Most of the field staff take the opportunity to drive north for a day’s visit to the Emu Field test site. Burns, Cooper and Williams stay behind to ‘have a play around’ at Taranaki.

  Suddenly, the readings begin revealing multiple radiation hot-spots that are definitely unexpected. The Pearce Report suggests the levels of contamination will remain fairly stable, and smoothly continuous – with no big changes over a 100-metre stretch, for example. Yet Burns, Cooper and Williams start to get wildly fluctuating readings over relatively short distances. This is not supposed to be happening. The scientists start to think about putting on face masks and other protective gear. At the Taranaki firing pads they are intrigued to find themselves kicking plutonium-soaked lumps of metal, rock and soil with their boots. Their Geiger counters go berserk near the hotspots. They find radioactive material in many places, particularly around the firing pads. The last of the big ‘mushroom cloud’ bomb detonations was conducted here. Between 1960 and 1963 it was also the site for the totally secret Vixen B radiological experiments. On 12 occasions during those years, simulated nuclear warheads containing plutonium were blown up using TNT.

  No-one can remember now why part of the Maralinga range is named after a region in the North Island of New Zealand. Perhaps it is related to the fact that New Zealand military personnel were part of the uniformed force stationed at Maralinga. Maybe it is an echo of the brilliant New Zealand scientist and Nobel Laureate Ernest Rutherford, whose basic nuclear physics research at Cambridge University made nuclear weaponry possible (although Rutherford was born on the South Island). Some people have speculated that the name was intended to be Tarakan, site of a battle during World War II in Borneo, but it was written down wrongly and the typo stuck. Certainly some of the other Maralinga test sites, such as Wewak and Biak, reference names familiar to Australian troops who served in Papua New Guinea during the war. Whatever the reason for the name, Taranaki will soon become infamous for its extensive radioactive contamination, the greatest amount on the Maralinga range. In fact, Taranaki will soon be revealed as one of the most contaminated places on the planet. The scientists, like all Australian officials, believed the plutonium was safely buried there, not spread around the landscape. When they report their findings, pressure will grow on the Hawke government, and soon a Royal Commission will be called that will systematically review what happened during the atomic tests. Amazingly, up to that time, the sovereign government of Australia actually has no idea.

  The scientists are perplexed by the wildly jumping radiation detectors and review their measurements. ‘I had a monitor in my hand, switched the speaker on and monitored the ground’, Peter Burns will say later, during an interview with the New Scientist journalist Ian Anderson.

  I ended up drawing a circle of about 2 inches in diameter, and you could sort of see the whole of the [radio]activity within that one little area. And Mal [Malcolm Cooper] got a shovel and dug it up and put it in a plastic bag. We monitored the hole again and there was nothing there, so we started squeezing around in this plastic bag and there was a lump of metal in the bottom.

  Williams uses two garden trowels bought at his local hardware store in Melbourne to investigate. He halves the soil sample repeatedly, with smaller and smaller portions containing all the activity, until he isolates the small metallic grey lump. Williams holds it in the palm of his hand – a discrete piece of blown-apart bomb debris loaded with plutonium. ‘Until that time, we had no idea we were looking for bits and pieces like that’, Burns will say.

  The British team testing the site in 1966 took soil samples back to the UK, but not the metallic lumps. The soil samples showed nothing untoward back then. Routine soil sampling would be highly unlikely to capture a discrete lump of extremely active material. But the ARL team now finds large quantities of plutonium on the ground.

  Plutonium. The material is not found in nature. It is created in a nuclear reactor by bombarding uranium with fundamental atomic particles called neutrons. In the words of nuclear chemist Glenn Seaborg, one of the team who created this dense, silvery substance in February 1941, plutonium ‘is unique among all of the chemical elements. And it is fiendishly toxic, even in small amounts’.

  Various kinds of plutonium were used in bomb experiments at Maralinga, but one of grave concern is particularly abundant – an isotope of plutonium known as plutonium-239 or 239Pu. Isotopes of an element have the same number of protons but differing numbers of neutrons. Protons define the elements, while neutrons can vary their properties. This means that while it is the same element chemically, each isotope has slightly different nuclear properties, and this leads to different physical behaviour. Plutonium in fact has up to 20 isotopes, each with the same number of protons but different numbers of neutrons. The highly toxic plutonium-239 has 145 neutrons and 94 protons in its nucleus, giving it a total atomic weight of 239.

  All the plutonium isotopes are radioactive and undergo a process of ‘decay’, releasing radioactivity in several different forms and eventually turning into other elements over time. The radioactive half-life (the time required for half of the nuclei of a radioactive isotope to undergo radioactive decay) of plutonium-239 is more than 24 000 years, much longer than the other plutonium isotopes. This long half-life means that plutonium-239 will be present in the environment so far into the future that it might as well be called forever. The persistence of its radioactivity is not the only reason plutonium-239 is especially dangerous. Even in small doses, it can cause terrible damage if absorbed into the body. By the time of the 1984 expedition the scientists know that it is subject to the strictest of controls; when the British were at Maralinga it was released onto the open range. To make it worse, much of the Maralinga plutonium was turned by the Vixen B tests into a fine form that could be inhaled. This made it potentially hazardous for anyone who encountered the dust of the area. The risks are well known: if you inhale 20 milligrams you will probably die of pulmonary fibrosis within a month. Inhaling a milligram will lead to lung cancer. The strange thing about plutonium is that it is relatively safe outside the body, and in fact you can touch a lump of it (as Williams does that Sunday). The alpha rays that it emits would not get past your skin. But once it’s inside the body, it turns deadly. It can be inhaled into the lungs, ingested through the mouth or absorbed through a wound, and if it enters the body through these pathways, there is a strong statistical probability that it will cause various kinds of cancers.

  The Pearce Report does not mention any fragments contaminated by plutonium. As a consequence, the AWTSC, whose job was to oversee safety standards at the Maralinga range during the tests and afterwards, disregarded the possibility that later visitors to the site might unknowingly pick up these fragments and take them away.

  The fragments are ejecta, metallic debris from firing simulated nuclear warheads during the Vixen B experiments. These so-called minor tests left terrible contamination, far greater than the more dramatic mushroom clouds. The simulated warheads containing plutonium were exploded using TNT. As a direct result the metallic scaffolds that held the assemblies aloft, the oddly named feather beds, were imbued with plutonium-239, as the ARL scientists, to their growing concern, are now discovering. The nature of the fragments varies. In some places, they will say in the report to be written directly after this landmark survey, are fractured pieces of steel, light alloy or other material coated with plutonium. The most radioactive piece found is a concave trapezoidal sheet of 12-millimetre steel plate, about 250 millimetres long and 120 millimetres wide, roughly the dimensions of a piece of A4 paper folded lengthways and pulled slight
ly out of shape. This metal has a massive 7 gigabecquerels (7 billion becquerels) of plutonium-239 on its inner surface. Most of the fragments are smaller, though, ranging from about half a millimetre to a few centimetres in length.

  The scientists also find evidence of plumes. These elongated hand-shapes on the ground trace the curves of the great clouds of fine plutonium oxide particles that lifted 1000 metres with each Vixen B detonation, were dispersed in the direction of the prevailing winds, then drifted down to the surface. The plumes splay out to the west, northwest, north and northeast of the firing pads. They can be detected because the plutonium carried back down still sits close to the surface.

  The Pearce Report says that 20 kilograms of the 22.2 kilograms of plutonium-239 is safely buried in pits at Taranaki, bulldozed and sealed in years ago. Why are the ARL scientists finding lumps of the stuff, and plumes picked out in surface-dwelling plutonium? An evenly dispersed sprinkling of sparse tiny particles would barely trouble the Geiger counters. But they are finding a web of hotspots that together contain kilograms of the most deadly form of plutonium known. It turns out the Pearce team back in the 1960s was made up of low-rank military personnel told to take various measurements without ever understanding the physics of what they were doing. Their measurements were effectively worthless. Because of the spotty nature of the plutonium hotspots, their monitoring methods totally missed the plutonium scattered all over the Maralinga range. The Australian Government accepted the return of the site from the British in 1968 on the basis of a fundamentally flawed report.

  As Peter Burns will drily observe years later, ‘If they had been as far out in their design of the bomb, they would never have been allowed to build atom bombs in the first place’.

  The analytical techniques of 1984 are more sophisticated than those of the 1960s, but there was still enough knowledge to survey the area properly back then. The wonder is why the British chose not to do the job they should have done but instead ordered untrained junior troops to walk around a relatively small part of the range taking surface alpha radiation measurements and picking up a few soil samples for analysis in the UK. Alpha radiation measurements are notoriously difficult to detect in the field because alpha particles emitted by radioactive elements travel only a short distance through the air. ‘Take the lackeys out there, start at ground zero, take a compass bearing, walk every 100 metres and measure, which is what they did. And frankly if you go out and try to measure like that now you would get the wrong answer’, Burns will later say.

  This inadequate technique produced a politically acceptable and expedient outcome but did not get anywhere near the truth. The ARL scientists are using a range of methods, including specially designed portable field probes for detecting the gamma ray emissions from the radioactive element americium, an excellent marker for plutonium in the environment. The peculiar physics of plutonium means that as it emits radioactivity over time, part of the plutonium is transformed into americium in a predictable way. Measuring the ratio of plutonium to americium gives a sensitive gauge of the true plutonium concentrations in the field. By 1966–67, americium would have been present in the surface soil at the site. Although the British did not have the same techniques for measuring americium then, they could have performed other kinds of experiments that would have given them a workable ratio. As Williams will tell Ian Anderson in 1993, ‘It is hard to see why they didn’t appreciate the physical deficiencies in the method that they used’.

  If an important part of the tests was getting information on where the plutonium ended up, the environmental consequences, then you would think they would put the effort into more scientific thought into getting those measurements more or less right. We know full well that other countries performing these experiments at the same time certainly did get it right. The Americans got it right. So you would think that the British would have given thought to getting those measurements.

  Why did they not put in the effort to get it right? We can only surmise now, but it is at least possible that the British had moved on by 1967 and their focus was to divest themselves of the inhospitably hot and remote Maralinga range. Perhaps they wanted to tie up the loose ends as efficiently and quickly as possible. A superficial and inadequate survey, unsupervised by Australian authorities, produced a convenient outcome. It was good enough.

  The British attitude since Australia started becoming restive over the issue in the late 1970s has been an irreconcilable combination of ‘there is no risk at the site’ and ‘if there is a risk, the Australian Government knew about it and accepted it, and it is their problem not ours’. Margaret Thatcher’s UK Conservative government will, later in 1984, present a submission to the Royal Commission that will say in part:

  The Australian government knew that the nuclear tests to be carried out [at Maralinga] would cause residual contamination and that, for that reason, public access to it would need to be restricted for the foreseeable future … Scientific knowledge is not now, and certainly was not then, sufficiently advanced to enable a complete decontamination of an area in which nuclear explosive tests have taken place. In 1955 [when the agreement to establish Maralinga was being negotiated] the Australian government did not seek such an onerous, if not impossible, undertaking from the UK government, nor would the UK government have committed itself to the use of the Maralinga range if it had contemplated any such requirement.

  But, as we will see, the British authorities did not tell the Australians that plutonium-239 would be dispersed in this way at the site. At the time of the agreement to establish Maralinga, the 1960s minor trials were not part of the negotiations. The Australians didn’t know exactly what went on at Taranaki until the ARL scientists discovered the reality and the science started pouring in after their landmark survey. Australia should have known, but it didn’t.

  Soon after the political delegation returns to Canberra from Maralinga, ARL makes contact with one of the visitors, the federal minister responsible for Maralinga, Senator Peter Walsh. They tell him that the site does not conform to the information in the Pearce Report. Walsh immediately announces in parliament that the scientists have found 28 plutonium-contaminated fragments at the site. The ARL scientists have provided the number 28 deliberately at this stage – a number they can verify based on the data available. When they started to get hotspot readings during their survey, the scientists conducted a scan across one of their rectangles, focusing their attention on a narrow area, and documented 28 fragments in that designated zone. Later surveys will ultimately find about three million fragments spread over square kilometres.

  The discovery of fragments is highly significant, not just because their presence undermines the assurances given by the British. Before this, everyone connected to the site believed that the major danger would be from inhaling the dust containing small particles of plutonium, although they think that this particular risk is minimal (a view that will soon also be challenged). The fragments suggest new risks. They are highly radioactive and if handled by people – for instance, visitors collecting souvenirs from the site – the radioactivity might enter the body by other means, such as through wounds. The Australians at the site have started to realise what they are facing.

  Each fragment is found to be significantly radioactive, measuring about 100 kilobecquerels or more. To put this into perspective, in Australian universities in the 21st century a researcher who wants to do an experiment using radioactive material that is 400 becquerels or more will need a special licence and training, and extensive special handling equipment. This for material that has only one-twenty-fifth the amount of radioactivity of each one of the fragments found at the Maralinga site during May 1984. Moreover, plutonium in these quantities is a safeguardable nuclear material. Under the terms of the Non-Proliferation Treaty of 1968 (which will be extended indefinitely in 1995), to which Australia is a signatory, all material that could be used to create a nuclear weapon has to be declared and prevented from being used for weaponry. Such material shou
ld not be lying around on the surface in collectible quantities. Then there are the fingerprints of British atomic weapons fuel remaining in that plutonium, which will shortly be discovered by the ARL scientists in their forensic ‘nuclear archaeology’ laboratory analyses of the material. The exact way that each nuclear nation makes its bombs is highly classified, yet the material left behind on the ground at Maralinga was open to analysis, thus revealing some of the secrets of the British bomb. Nothing could be more foolhardy or irresponsible, not to mention the mockery made of all the paranoid secrecy during the test series in Australia. Millions of these fragments will eventually be found lying on or just below the surface at Maralinga, readily accessible to anybody casually visiting the area. The Pearce Report contains no hint of this possibility.

  A long period of analysis of the Maralinga site will follow this fateful ARL visit. The ARL scientists will document the major discrepancies between the levels of contamination claimed in the Pearce Report and what they have found on the ground and will present several influential reports to the Royal Commission. Later still, even more damning information will detail the magnitude of these discrepancies and British culpability (see chapter 11).

  Later in 1984, Peter Walsh speaks several times in federal parliament about Maralinga. This issue is both a growing priority and an irritant to him. The treasurer Paul Keating nicknames him Sid Vicious because of his dour, unsentimental personality and his tough, pragmatic approach to all issues in his portfolio, including Maralinga. In a lengthy statement to parliament on 4 May 1984, Walsh confirmed that he was seeking to release publicly the entire Pearce Report. That week investigative journalist Brian Toohey published his brilliant National Times story based in part on the leaked report. In his parliamentary statement, Walsh said, ‘Let me assure the Senate and the Australian people that this Government has no interest or intention of keeping facts relating to the nuclear tests in Australia secret’.