Atomic Thunder
Page 14
The first Kittens trials at Emu Field were intended to test ‘initiators’ – mechanisms within the atomic assembly that switch on the supply of neutrons to enable a chain reaction. The experiments concerned timing the release of neutrons used by a fission weapon to split the atom. The five Emu Field Kittens experiments used the toxic (but non-radioactive) element beryllium as well as the short-lived radioactive element polonium, releasing both into the local environment. William Penney said the Kittens experiments were undertaken in Australia rather than in the UK ‘since they could be done in conditions where dispersal of the short-lived radioactive material used in the initiating of the nuclear explosion would not pose a hazard’.
Rats and Tims were held at Maralinga. The Rats experiments measured how materials were compressed under the high pressure inside a nuclear warhead when it was detonated. Tims was similar to Rats but used a different measurement method. In the Tims experiments, one of the materials measured was plutonium, so Tims left more significant contamination.
They were initially called minor trials, and this was followed by other innocuous names – in 1959 there were ‘assessment tests’ and from January 1960 the Maralinga Experimental Programme, often abbreviated to MEP. Justice James McClelland commented on the ‘almost comical touch of camouflage in the changes of name of the minor trials’, especially given the ban on nuclear tests being negotiated at the time.
Vixen B investigated questions about safety of storage and transportation of nuclear material. How would bombs and related paraphernalia behave if, for example, a plane laden with nuclear warheads crashed on take-off? The ‘broken arrow’ scenario – ‘an unexpected event involving nuclear weapons that results in the accidental launching, firing, detonating, theft or loss of the weapon’ – loomed large after several crashes of aircraft carrying atomic weaponry. Since 1950, a large (and mostly secret) array of accidents involving nuclear weaponry had occurred, sparking fears of a nuclear catastrophe caused by accident or terrorism.
When Vixen B was first planned in 1958, Britain had undertaken six years of atomic weaponry testing, and its nuclear arsenal was sufficiently advanced to go into operational deployment. Blue Danube was a tactical nuclear weapon (soon to be replaced by the smaller Red Beard), deployed to the RAF. When the Vixen B series began in 1960, Britain had rejoined the newly amenable Americans and, among other things, embarked upon a series of similar tests. The US Roller Coaster tests, which examined environmental dispersal of plutonium, had slightly narrower objectives to Vixen B, but similar methods. The Vixen B tests in Australia explicitly addressed the broken arrow scenario in addition to plutonium dispersal. Some people also suspected that Vixen B was more than just a safety test series. According to nuclear engineer Alan Parkinson, ‘While they were said to be to test the safety of nuclear weapons in storage or transit, there was also an element of weapons development in these trials’. The data from Vixen B are still retained by the UK Ministry of Defence, long after the 30-year rule, meaning no-one is entirely sure exactly what they found or how it was used for weapons development.
The 12 Vixen B experiments at Taranaki between 1960 and 1963 involved blowing up plutonium-239 with conventional explosives. Nuclear warheads were strapped on feather beds 2 metres above the ground and subjected to so-called one-point safety trials. This meant detonating one point in a matrix of, say, 32 points of high explosive that must all explode in a rapid sequence to ignite an atomic blast. The plutonium was contained within the bundle of explosives. When the explosive was detonated, the plutonium was compressed and became molten. Plutonium is pyrophoric – it burns on contact with air – and when blown up it produced an aerosol of plutonium oxide particles that spread out from the Taranaki site. Narrow plumes of plutonium aerosol stretched many kilometres out in a hand-like shape over the northwest to northeast. The one-point trials were intended to show that igniting one point in the matrix would not set off the nuclear fission of an atomic blast and apparently succeeded in doing so, at least for low-yield weaponry.
This form of experiment was dangerous, as the British acknowledged in their secret correspondence. AWRE safety co-ordinator Roy Pilgrim noted in a memorandum ‘the potential catastrophic nature of a mistake’ and urged ‘rigid adherence to the planned procedure’. The tests were not intended to produce nuclear reactions, but, in the event, as secretly predicted by the British, fission and fusion reactions did occur. Indeed, Pilgrim discussed fission openly with Ernest Titterton in a letter of October 1962, saying, ‘Whereas for previous Vixen B firings the experiments were so designed that fission products could not be present in quantities sufficient to add a radiotoxic effect … we are now seeking greater flexibility in the design of the experiments and to achieve this we need the freedom to plan in such a way that fission products may be generated’.
While the Vixen B test series used most of the plutonium-239 that contaminated Maralinga, various isotopes of plutonium were used extensively in other minor trials too. In one Tims trial, half a kilogram of weapons-grade plutonium was fired into a pad filled with salt, and six drums containing the contaminated salt were then buried at the Maralinga airport cemetery. This plutonium was mostly plutonium-239, along with some shorter lived isotopes – plutonium-240 and a tiny amount of plutonium-241. The plutonium from this test became the centre of a media controversy in 1978 when a secret Cabinet submission revealing the burial site was leaked to journalist Brian Toohey (see chapter 10). It was repatriated to Britain in 1979, the only loose plutonium from Maralinga to be recovered.
These high explosive tests ceased in 1963 when both Britain and Australia became signatories to the United Nations Partial Test Ban Treaty that outlawed atmospheric testing. The official name for the partial test ban treaty was Treaty Banning Nuclear Weapons Tests in the Atmosphere, in Outer Space and Under Water. It was signed in Moscow on 5 August 1963. An earlier moratorium on nuclear weapons testing, from 1958 to 1961, may have been knowingly subverted by the British test authorities in the case of the Vixen B tests, largely through the use of innocuous names (‘minor trials’, ‘assessment tests’), and without telling the Australian Government exactly what the tests involved. John Moroney wrote later:
Both [the UK and US] believed that these [one-point] studies were not nuclear weapons tests within the terms of the moratorium, but they were anxious not to be seen to be infringing the terms in any way. Accordingly, they performed the tests on reduced assemblies of the fission triggers to ensure that any nuclear yield was small, and conducted them under tight security, away from prying eyes.
As a direct result of the Vixen B tests, the feather beds, and lots of other equipment and buildings in the area, became impregnated with the most dangerous plutonium isotope, plutonium-239. The explosions created a kind of ‘dirty bomb’, releasing significant quantities of radioactive material into the atmosphere and subsequently onto the ground. In a submission to the Royal Commission, the ARL (now ARPANSA) ‘estimated that there were between 25 000 and 50 000 plutonium-contaminated fragments in the Taranaki area, although the number might need to be doubled if missed and buried fragments were included … The finding of this large number of plutonium-contaminated fragments was a surprise and changed the whole concept of hazard assessment of the plutonium-contaminated areas’. Over time, this calculation was revised to three million fragments. Staging the Vixen B trials cost Australia a lot of money – the cost for the first series alone was over £25 000 in labour, materials, plant hire and other expenses. It reaped three million loose fragments of plutonium.
Small particles of plutonium can be picked up readily in dust and can swirl around the landscape. Anyone in the vicinity might breathe it in. It is an insoluble particle that, if inhaled, lodges in the lungs, where it can stay throughout a person’s lifetime and irradiate its surroundings, possibly causing lung cancer. The risk is precisely proportional to the dose. If a person breathes in enough plutonium-239 to receive a dose of 1 millisievert (a unit of biological absorption of ionising
radiation) the risk that he or she will get lung cancer is about one in 20 000. If a person ingests or inhales enough to receive a dose of 100 millisieverts then the risk is one in 200.
Leaving such a substance lying around on the ground was reckless. The widely dispersed Vixen B plutonium was not enough to kill people immediately through radiation sickness, but it could cause cancer over longer time frames. Given the ‘dusty lifestyle’ of the Indigenous population in the area, this was an unacceptable risk according to accepted international guidelines on the use of radioactive substances. While the AWRE maintained it followed the protocols laid down by the International Commission on Radiological Protection at the time of Vixen B, the plutonium contamination around Taranaki shows these assurances to be unfounded. The commission protocols relevant to the British tests were established in 1950 and updated several times during the test program, most notably in 1958. By the time of Vixen B these protocols had established that there was no threshold above which exposure became dangerous. Any exposure was dangerous.
Another risk was visitors coming to the site and picking up ‘souvenirs’, also unacceptable under the guidelines. To this day, no-one knows if such mantelpiece ornaments are out there – for several years during the 1970s the test range was not patrolled, and anyone visiting the area could have picked up a lump of plutonium-soaked rock or metal. The Commonwealth Police provided security services at the Maralinga site throughout the test program and remained there until 1 March 1974. In December 1976, when stories started appearing in the South Australian media about the Maralinga aftermath, the Australian Federal Police resumed surveillance. In between, only two civilian caretakers were on site.
In 1979, as the Maralinga story was breaking in the national media, South Australian scientists found that 19 rabbits around the Taranaki site had taken up a variety of radioisotopes in their fur, including plutonium-239, and this was cause for some consternation. In their report, quoted by Australian journalist Robert Milliken, a prominent chronicler of the British nuclear tests, they noted, ‘It is possible for rabbits, that are notorious for their ability to excavate burrows in almost any material, to gain access to the [Taranaki test debris burial] pits by simply burrowing under the 6 inch concrete slabs … As we are discussing products that have a half life of 24 000 years, it would seem almost a statistical certainty that in some time in the future the rabbits may have access to a pit’. The pits were dug into limestone, which formed the walls of the pits, and capped with concrete.
After the well-controlled media coverage up to the mid-1950s, from 1957 onwards journalists stopped writing stories about the British atomic tests. Once Howard Beale had gone to Washington and William Penney was engaged in Operation Grapple in the Pacific and, later, with the UK Atomic Energy Authority, the ongoing activities at Maralinga were not reported. However, both the British and the Australian authorities knew the Vixen B trials might attract media interest and planned for it. A sequence of correspondence in the second half of 1960 disclosed some of the official thoughts shared between the respective governments.
On 27 September 1960, Maurice Timbs, assistant secretary in the Prime Minister’s Department (and from 1964 to 1973 an executive member of the Australian Atomic Energy Commission), sent Menzies a statement drafted by the British, to be used ‘in the event of any public disclosure of the existence of these experiments [Vixen B] … The intention is that it will be held in readiness and released only if there is a public disclosure that these experiments are being carried out’.
The letter had a handwritten annotation, above Menzies’ initials: ‘Discussed with Mr Townley [Defence minister] and approved as amended’. An attached media statement with handwritten corrections asserted that no nuclear explosions were being carried out on the Maralinga range. More detailed information about the activity at the range was crossed out, in particular a statement that the experimental program involved radioactive or nuclear materials. What remained was the following:
The Range is being used for experiments conducted on behalf of the United Kingdom Energy Authority which has a need to explore systems of safeguards [the previous few words crossed out by hand] to eliminate or to minimise the hazards which could arise from accidents involving radio-active materials. The Australian Government has agreed to the use of Maralinga for these experiments which are carried out in accordance with the requirements of the Safety Committee established by the Australian Government and under carefully controlled conditions to avoid any significant radio-active hazard.
On 20 October, the office of the UK high commissioner in Canberra replied, unhappy with ‘systems of safeguards’, saying it ‘may lead to difficulties and misunderstandings’ because it was similar to terminology being used in negotiations for the new Geneva nuclear weapons treaty. The International Atomic Energy Agency (IAEA) was also using the term in regards to civil uses of nuclear technology. ‘Thus the term “systems of safeguards” has already acquired rather special connotations. It is therefore felt that it would be better if possible to avoid it in the draft press statement.’
After further correspondence, a final version – with ‘systems of safeguards’ removed – was watered down a little more to produce a 100-word media statement. It was never issued, because no journalist ever inquired. Despite growing public disquiet since 1956, the media did not notice the signs that major activities were afoot at Maralinga, overlooking the increases in military personnel and much to-ing and fro-ing. Unless an official media release heralded it, the media seemed to show no interest in the events at Maralinga. Of course, this suited the British test authorities, who consciously sought to maintain secrecy.
The media blackout that descended over Maralinga was extremely successful. Given both the level of previous coverage of the British nuclear tests and the rise of anti-nuclear movements throughout the world, the lack of media activity is conspicuous. Vixen B, a test series that ran for three years and involved hundreds of personnel on site, does not appear to have been covered at all. As Lorna Arnold wrote, ‘Outside official circles, very few people apparently realised that Maralinga was used for these experimental programmes, and that it continued to be used after Antler’.
Arnold claimed that the British authorities were ‘particularly anxious’ not to attract any publicity during international negotiations to limit nuclear weapons testing. Vixen B was the major reason for this anxiety, since it produced nuclear fission, albeit in small amounts, and tested an apparatus that came close to many of the characteristics of an actual nuclear warhead. Vixen B was right on the borderline of international law and may have crossed into illegality. The behaviour of the AWRE authorities at the time suggests that they knew Vixen B was in a grey area and political reasons dictated secrecy.
Intergovernmental moves to find a politically acceptable way to slow the race for nuclear arms had begun in 1958. US president Dwight Eisenhower had proposed that test ban negotiations should begin on 31 October that year, pledging a one-year moratorium on weapons testing, and the Soviet Union had agreed. On that date, the Conference for the Discontinuance of Nuclear Weapons Tests had opened in Geneva. A moratorium on the testing of atomic weapons actually stayed in place until September 1961. In 1963, a permanent partial test ban treaty came into effect.
The Geneva agreement was a complication for the AWRE. The UK weapons authorities had no choice but to comply with the agreement, which was binding on the UK. On the other hand, they had an extensive program at Maralinga and plans to expand it. The easiest thing to do was to behave as though the minor trials were not happening. The attitude of the time was summarised by the Australian chronicler of the tests, John Symonds: ‘There is no reason to believe that these experiments could be regarded as an evasion of a Treaty, whatever the outcome of the present Geneva discussions. While there is no need to raise the point specifically in Geneva, there is no need to deliberately conceal it, but no public statement is to be volunteered’. Without public statements, there was no media coverage.
The dangers were grave, although there is considerable dispute about their extent. Lorna Arnold took the view that the people exposed to the tests were not seriously affected by radiation, doses of which she said were well within the guidelines laid down by the International Commission on Radiological Protection: ‘The people most affected … were the Aboriginals, because of damage to their way of life rather than directly to their health. They had no rights and their interest in the land was not realized or respected; but this was, and had been, their general situation and was neither new nor peculiar to the weapons trials’.
Vixen was initially proposed as one kind of test, but it evolved into two – Vixen A and Vixen B – a year or so after its first formulation. Vixen A, the original form of the experiments, used mostly beryllium and small quantities of plutonium. It involved studying how radioactive and toxic materials including beryllium, uranium and plutonium might behave in an incendiary or explosive accident and specifically examined how weather conditions influenced the spread of such materials. The tests involved burning the substances in a petrol fire or electric furnace, or dispersing them by high explosive. Thirty-one Vixen A experiments were carried out at the Wewak site, about 15 kilometres to the southeast of Taranaki.