Atomic Thunder

by Elizabeth Tynan

  The Vixen A experiments were troublesome for several reasons, not least because the balloons used to hoist a variety of monitoring devices aloft before detonating the bundles of radioactive materials kept slipping their moorings and heading off into the open sky. After one such incident in July 1959, a balloon was found the next day about 10 kilometres away from the test site. Another escaping balloon was not found. The balloon accidents associated with Vixen A caused major disruptions to the test program. In fact, these problems turned out to be a foretaste of more serious balloon incidents in September 1960 connected with Vixen B.

  During a storm on the night of Friday 23 September 1960, seven of the eight captive balloons that had been placed for the start of the Vixen B experiments broke free. This was before the first Vixen B experiment, so the balloons were not contaminated. One of the balloons was discovered at Hungerford just over the New South Wales–Queensland border, about 1400 kilometres from Maralinga, and another at Cobar in New South Wales. The recovered Cobar balloon was found to have a faulty mooring system. Test authorities were worried that the footloose balloons would provoke media reports, but while some media did report the escaping balloons, none gave much detail.

  After these incidents, the Australian Department of Defence ordered an inquiry, which was carried out by a senior official from the Department of Supply (and included John Moroney on the committee). It recommended that the use of balloons be restricted and proper safety plans be formulated. The inquiry had found that ‘a safety plan … did not exist … In consequence, the necessary criteria had not been laid down to ensure the development of such balloon safety and mooring systems and handling procedures that would have avoided any escape from the Maralinga range’.

  Vixen B proceeded despite the balloon dramas and ongoing problems with the weather. The health and safety controls for these dangerous new experiments included a larger than normal stand-clear zone and dosimetry gauges to detect radiation to be worn by all site personnel. Those in the forward area close to the firing site also wore radiation protection suits, gloves, boots and full-face respirators. The only personnel allowed to be stationed close to the Taranaki site during Vixen B were British service personnel and AWRE representatives; not even the Australian health physics representative Harry Turner was allowed onto the Taranaki site during a firing. Turner’s health physics unit was involved from a distance, however, since the health physics requirements for Vixen B were the most demanding of the tests after the major trials.

  The exclusion zone in the first Vixen B in 1960 was within a radius of 40 kilometres from the place of detonation. This was expanded to 43 kilometres in 1961 and ultimately to 56 kilometres by 1963. This compares with safety radii of between 5 and 25 kilometres for the other minor trials conducted at Maralinga at that time. John Symonds noted that the larger than normal safety zones induced speculation and curiosity. Years later, Moroney told his colleague Geoff Williams that ‘there was a genuine concern, albeit small, that one of the Vixen Bs could indeed have gone full nuclear’.

  The greatest area of radiological contamination from the Vixen B tests was found in, roughly, a 1-kilometre radius from the firing pads. Arrays of sampling instruments were arranged to the north of the Taranaki firing range, to measure atmospheric dispersal and contamination levels for each Vixen B firing, although bad weather often compromised the readings.

  The Vixen B assemblies were deliberately made to fit a definition imposed unilaterally by the AWRE (a definition not ratified by the Conference for the Discontinuance of Nuclear Weapons Tests in Geneva) that they ‘did not give a nuclear reaction in excess of ten tons of fission TNT equivalent’. At the Royal Commission, WE Jones, the AWRE’s co-ordinator of operations for Vixen B, revealed how the test authorities skirted around the new international restrictions on atomic testing. McClellan asked him, ‘In scientific terms there was no difference of real significance if you stayed under the ten tons, but the chances are you would not get caught, is that right?’ Jones: ‘I suppose that is a way of putting it politically’.

  Each Vixen B blast blew the feather beds apart, so they could be used only once, after which they were buried in pits dug close to the Taranaki site. British engineer Raymond Carter, at the site during Vixen B, later asserted that the ‘quantities of contaminated debris at the Firing Sites had been much greater than originally planned’. In total, Vixen B scattered 22.2 kilograms of plutonium-239 around Taranaki. Although exact figures have never been established, it was later found that rather than 20 kilograms sitting safely in the Taranaki burial pits (there were 19 pits at the time, and two more were dug during the clean-up operations), it was actually spread all around the site, and well beyond, in particles of widely divergent sizes. When Vixen B was underway, a wire fence enclosed the contaminated areas with ‘keep out’ signs hung at regular intervals, while maps prepared for site staff showed the areas not to be entered. Most of the fences and signs were removed during the Brumby clean-up operation in 1967, in an effort to return the site to its pre-test appearance. In effect, the visible signs of the British tests were removed, but the invisible and more dangerous residue was not.

  Plutonium-239 is a dangerous and persistent substance that delivers ionising radiation – the kind that changes the cells of a living body by knocking electrons out of stable atoms – when ingested or inhaled. It must enter the body to do harm – its weak alpha particles can travel only a few centimetres in air. Plutonium is one of the most toxic substances known, and its modern-day uses are strictly controlled, with licences and transparent monitoring protocols required. The small amount of plutonium-239 used in Australia these days is mostly under the auspices of the Australian Nuclear Science and Technology Organisation, which adheres to safety requirements laid down in the Australian Radiation Protection and Nuclear Safety (ARPANS) Act 1999, in addition to the ARPANS Regulations 1999. It is used mostly as a measurement standard and to calibrate radiation detection equipment. It can no longer be blown up or spread around an open landscape. Current protocols for the use of plutonium both in Australia and internationally recognise its dangers, including its potential for terrorism. According to scholar Shaun Gregory, ‘It has been estimated that one millionth of a gram of plutonium-239 may be sufficient to cause lung cancer if inhaled … The fissile core of a single weapon would, if perfectly dispersed so that each individual had one millionth of a gram in his or her lungs, be sufficient to threaten cancer in every single member of the human race’.

  When plutonium was blown up on the feather beds at Taranaki, the main safety procedures were an exclusion zone during the detonations and some safety equipment, often not properly used. Later many service personnel sought compensation for damage they claimed to have suffered based on several main factors, including the lack of information they received and the inadequate safety measures in place during the tests, particularly Vixen B.

  Plutonium poses two main kinds of health hazards: deterministic (also known as non-stochastic) and stochastic. The deterministic hazard involves a threshold level of radiation exposure above which people may be severely harmed or killed, sometimes quickly – for example, by radiation sickness. The stochastic hazard, on the other hand, is based on the probability of developing cancer or genetic damage, which is directly correlated with dose. There is no threshold, meaning in effect that if a given number of people are exposed to any amount of ionising radiation, the probability is that a statistically predictable number of them will suffer cancer or genetic damage. There is no safe dose; any exposure may cause risk of serious illness.

  The best known anecdote of deterministic harm caused by British nuclear tests is the ‘black mist’ experienced by Indigenous people (see chapter 7). For the minor trials, the stochastic effects have caused the greatest concern. These occur over a long time so may not be apparent for many years after exposure. This means the risks are hard to manage and to compensate, particularly since medical science cannot distinguish if a specific cancer is caused by radiat
ion. The kind of contamination present at Maralinga does not pose a hazard when outside the body. Inside the body, the dangers are immense. According to Dr Keith Lokan, then head of the ARL, plutonium particles

  may remain in the lung for a long time where they may expose the lung tissue and give rise to lung cancer. Alternatively … because of its long residence time, this material can very slowly dissolve in the lung fluids. Once it goes into solution … it can cross the boundary between the lung and the bloodstream and then make its way to the bones, and it is acknowledged as a potential source of some forms of bone cancer.

  Given the character of plutonium-239, it seems remarkable now that the AWRE authorities did not name it when they briefed the Australians on the Vixen B test series. In the end, this backfired. The Australian authorities began to wonder why they seemed to be cut off from crucial information and eventually changed how minor trial information was provided. As a result, planning for the Vixen experiments did not proceed smoothly. Without doubt, this was more to do with the associated politics and the increasing restiveness of the Australian Government than what now seems to be the sheer foolhardiness of the experiments themselves. When the British were devising the Vixen series, even the notably compliant Australian authorities were starting to have serious doubts, not least because the tests seemed, even to a superficial examination, close to breaching the nuclear weapons moratorium agreed in Geneva. This jousting with international law was becoming a cause of disquiet among the select few who knew about the tests in Australia, as well as much scrambling among the British authorities to make the minor trials fit the new treaty conditions.

  The concern about the tests being made public meant that shipping in about 500 personnel to carry out the 1961 Vixen B tests posed a potential threat to security. Noting this, John Symonds commented, ‘A disclosure that an operation of the present magnitude was in hand would be difficult to handle’. AWRE officials first hinted to the Australians that they proposed to use the long-lived isotope of plutonium in May 1959. However, the exact description was revealed only after repeated inquiries. The AWRE wanted to augment the existing Vixen series ‘by adding a few burning trials to determine the dispersion of plutonium under representative field conditions’. The AWRE endeavoured to slip these tests under the radar, using the cover of Ernest Titterton’s insider soundness. Titterton was explicitly criticised by the McClelland Royal Commission over the minor trials, in part because he had advised the British to say that the fission yield of the 1960 Vixen B tests was zero when he knew it was not: ‘The yield was expected to be small, even very small, but not zero’, the report said.

  Roy Pilgrim, head of safety co-ordination for the AWRE at Aldermaston, issued the highly confidential and later contentious MEP 1960 safety statement at the end of 1959. The 1960 experimental program mentioned Vixen B for the first time, but without specifics: ‘Vixen B firings will use long lived radioactive elements including fissile materials. In some rounds the possibility of a fissile reaction is envisaged but the quantity of fission products which would be produced is not radiologically significant compared with the parent material’. A short, handwritten list at the end of the document contained the names of people to whom copies should be sent, including Titterton. The report of the Royal Commission noted that Titterton ‘did not advocate a further formal approach through the Commonwealth Relations Office because, inevitably, detailed questions would be asked about the precise nature of the experiments, and how they differ from those already approved’. The sorry saga of how the British tried to dupe the Australians about the true nature of Vixen B had a finale of sorts in London in 1985, as Noah Pearce felt the hostile glare of the Royal Commission. Peter McClellan put it to Pearce, ‘You would agree that the 1960 [Vixen B safety statement] document certainly was a totally inappropriate basis on which to form a judgement as to the safety of what was proposed?’ Pearce had no choice but to meekly agree.

  The tussle over Vixen B between the UK and Australia was only one side of the issue. For the AWRE authorities back at Aldermaston, the main problem was events in Geneva. A 1958 document prepared at Aldermaston by the AWRE’s senior superintendent of weapons assembly AR Bryant under the direction of the assistant deputy director of the AWRE Admiral PWB Brooking shed light on this. In a top-secret memorandum titled ‘Maralinga Minor Trials in Relation to a Ban on Nuclear Testing’, distributed only to three other people including Brooking, Bryant acknowledged that increasing evidence showed most of the minor trials could be safely carried out in the UK, except for

  the precise wording of a statement given by Lord Salisbury to Parliament, which in fact bans firings at Foulness [the AWRE test range on the Thames estuary] using hazardous materials, even in amounts so small that the experiment as a whole involves no hazard. This illustrates the importance of precise phrasing and definition in any policy ban imposed internally in the United Kingdom.

  In the UK House of Lords on 7 April 1954, the marquess of Salisbury, the lord president of the council, had stated, ‘I can say definitely that no nuclear explosions have been or will be made, nor will experiments be made with fission products or any other hazardous radioactive material’. According to the Royal Commission, this statement was often cited ‘as constituting an unbreachable veto on the use in Britain of radioactive materials in explosive nuclear experiments’. Bryant’s memorandum suggested two definitions of minor trials to ensure no apparent conflict with the international ban on nuclear testing. The first was a trial in which ‘small amounts of radioactive or fissile material are involved in association with the detonation of conventional high explosive in such a manner that no fission results’. The second was a trial in which ‘radioactive materials are not dispersed so as to exceed certain agreed tolerance levels outside some agreed radius X miles from an agreed site Y’. Neither of these definitions applied to Vixen B, which clearly produced fission – soon to be acknowledged in Pilgrim’s safety statement – and whose radioactive materials were dispersed in plumes far beyond an agreed radius and tolerance levels.

  In a top-secret note to Sir William Cook, the AWRE chief scientist leading the British H-bomb project in the Pacific, Brooking explained why he had ordered the memorandum. If Britain had to continue its trials after internationally agreed suspension, as he assumed, it would need ‘Ministerial and Australian agreement’ on a definition which, ‘to be useful to us, must not rule out trials involving RadioActive [sic] materials (e.g. Rats) or even fissile material’.

  A few weeks later, when Brooking wrote to Cook to put in writing further advice the pair had been discussing, he observed, ‘If we are convinced that Maralinga is THE place to do these “unsuspended” trials, then the Australian Government will have to be told or asked’, though he noted that this would have to wait until after the Australian elections in November. In the meantime, however, in the light of the international agreement it was essential that the UK and US agree on a definition of what ‘we are willing to suspend’ so that at the October talks in Geneva both sides would ‘talk with one voice’. Brooking also recorded that Cook felt ‘radio-active contamination in U.K. is politically impossible’.

  The tests continued to take place at Maralinga. Now that the US had removed the decade-long constraints on joint UK–US atomic weapons development and testing imposed by the McMahon Act, they soon took place in Nevada and Los Alamos too. Personal rapport between the UK prime minister Harold Macmillan and President Eisenhower helped the two old nuclear weapons partners to resume their relationship, just as the Soviet launch of the Sputnik satellite in 1957 raised geopolitical tensions and made rapid Western technological progress more urgent than ever.

  Brooking wrote another letter, on 29 September, discussing in more detail the definitions of minor trials doing the AWRE rounds:

  From the purist’s point of view it might be taken to rule out ‘single point detonation’ trials and maybe certain nuclear trials which could give rise to small amounts of fission. We can however argue that such f
ission is not the intention of the trial and that if we did produce any it would be an accident, which we are, of course, unable to guard against.

  This appears to imply that fission could be produced ‘accidentally on purpose’, after which culpability could be plausibly denied if they were found out. Brooking noted the US intended to do the same ‘if their politicians will let them’. And they did, with the Roller Coaster experiments in Nevada.

  Justice McClelland took a jaundiced view of this series of AWRE documents, used as evidence during his Royal Commission. ‘The disingenuous tone of this debate … hardly encourages a belief that the Royal Commission has been told the full story of the minor trials.’

  AWTSC secretary John Moroney had pointed to potential problems with plutonium from the Vixen B experiments in November 1963. He wrote to Roy Pilgrim, setting out his concerns about the test range:

  » Residual plutonium will continue to constitute the predominant radiation hazard at the Range.

  » There are a few areas, which we believe to be well protected, in which the plutonium levels could constitute a serious radiation hazard.

  » The present residual plutonium contamination at Maralinga will continue to be a potential hazard for many years and far beyond the period for which activities at Maralinga of the MEP type can be envisaged.

  Moroney correctly pointed out that the main hazard at the site was from inhalation of the dust. ‘Experience at Maralinga indicates that plutonium moves quickly into the top few millimetres of soil; we do not know how deep it will move ultimately but in a low rainfall region such as Maralinga it may not go far.’ He suggested that using the Maralinga site to conduct experiments to assess the hazards of soil-borne plutonium would be a good use of the facilities.