Maralinga Mystery

Prologue

In 1956 and 1957, seven atomic bombs were exploded at a remote site named Maralinga in the state of South Australia. Australia has never had, and has never possessed, nuclear weapons, so the question is how could there be atomic explosions in a country that has never had such bombs? And, to add to the mystery, in the period 1960–63, another fifteen bombs were exploded in a manner which precluded nuclear detonation, but which spread plutonium and uranium over a vast area of pristine Australian bush. The answer to my question is that Australia wished to have nuclear weapons and hoped to gain access to the technology by collaborating with Britain as they developed their weapon. Part of that collaboration was to allow Britain access to Australian territory to test the weapons, and it was British bombs that were tested and exploded.

In 1993, the Australian government embarked on a partial clean-up of a small portion of the most contaminated part of the site. A couple of years after the project was complete, a ‘final’ report of the project was tabled in the Australian House of Representatives on the 25th of March 2003, by the Minister for Science, Mr Peter McGauran. The minister said, "It is with a considerable sense of accomplishment that I table the report of the Maralinga Rehabilitation Technical Advisory Committee, MARTAC, entitled Rehabilitation of former nuclear test sites at Emu and Maralinga (Australia). He continued, The MARTAC report describes in detail the $108 million clean-up of the former British nuclear test sites in South Australia. The project achieved its goals and a world best practice result. He concluded, I commend the MARTAC report to members."

Mr Albanese, the Labor Member for Grayndler, was the first speaker to respond, saying, It is with a considerable sense of sadness that I respond to the statement of the Minister for Science on the Maralinga Rehabilitation Technical Advisory Committee report. He continued, "The minister has said that the clean-up is world’s best practice. The importance of this claim to the minister was evident when, in the course of his statement, he attempted to explain away the dumping midstream of the preferred in situ vitrification of treating contaminated material, going instead for a cheaper reburial option. He added, What we are left with is a cheap and nasty solution which certainly saved money but which failed to meet the standards adopted at the outset of the rehabilitation process and which also failed to conform to international safety standards and practices."

Two differing claims. They cannot both be right. Which is to be accepted and which rejected? Should it be the Australian approach adopted by the department and supported by Mr McGauran, or the international approach, which had been carefully planned and initially adopted, and favoured by Mr Albanese? Did the project conform to international practice or not? Did the project achieve its goals as claimed by Mr McGauran? Why did the department reject the plan developed by their own advisory committee? Did the department really make any savings by adopting the simple burial approach in preference to the original, carefully considered and approved, plan?

The project had its beginnings in the immediate post-war years, but was not concluded until almost seventy years later, although one might argue that it has not been concluded even now because the plutonium contamination on the ground surface will remain for thousands of years. The partial clean-up was possibly the largest project of its kind in the world in terms of area. It still attracts both national and international attention, and the controversial end puts a blemish on a project that had promised so much.

Australia’s Nuclear Program

Chapter One – Atomic Jargon

This book is really about three projects that were years apart. The first was Britain’s development of its own atomic bomb with considerable willing assistance from Australia, and that project was inextricably linked to the third, which was dealing with the aftermath. In between was Australia’s second attempt to acquire nuclear weapons. I was far too young to be associated with the first project, but I was involved in both that second attempt and the aftermath of the British program.

A detailed understanding of nuclear jargon is not necessary to understand this book, but some atomic jargon, such as isotope and half-life, is unavoidable. To give my readers some help, I explain these and a few other terms in a manner that is easily understood, and I can think of no better place to do so than in this opening chapter.

The starting point is of course, the atom, which the ancients thought were the smallest things in the universe and could not be divided. We now know that is not the case. An atom consists of a nucleus, which comprises protons and neutrons, with orbiting electrons. The proton holds a positive electrical charge, which is balanced by the negative charge of the orbiting electrons. The neutron has no charge. The number of protons in the nucleus determines the element. While the number of protons is static for each element, the number of neutrons varies, and these variations are known as isotopes. Isotopes of the same element have the same chemical properties, but different physical properties, so generally the separation of different isotopes of the same element is achieved by physical means.

There are ninety-two elements which occur naturally, and they can be plotted on a chart of the nuclides. At the bottom of the chart is hydrogen. An atom of hydrogen has a single proton and no neutrons, but one in every 6,400 hydrogen atoms contains a single neutron; that isotope is known as deuterium. When hydrogen is combined with oxygen, it forms water, but if one hydrogen atom contains that neutron, the outcome is heavy water, and that occurs in one in 3,200 cases. But pure heavy water requires two of those deuterium atoms to combine with oxygen, and that occurs only once in 41 million cases. So, most heavy water is not pure but is a combination of the two types, plus a very small fraction of ordinary water.

At the top of the chart of naturally occurring elements is uranium, which is given the symbol ‘U’. It contains ninety-two protons and differing numbers of neutrons. Natural uranium, as it occurs in nature, comprises three isotopes: 99.3 percent is U-238, 0.7 percent is U-235 and there is a very small trace of U-234. Uranium-238 contains 92 protons and 146 neutrons, hence 92 + 146 = 238. Uranium-235 contains only 143 neutrons and 92 + 143 = 235. Uranium-235 is what we call ‘fissile’ which means that the nucleus can be split (fissioned) whereas U-238 is not fissile but can be made to split or can fission spontaneously.

Since the advent of nuclear energy, several more elements now exist beyond the top end of the chart, these are known as transuranic elements and one in particular is important in this work, that being Plutonium-239, which is made in a nuclear reactor.

These sub-atomic particles were discovered during the period from 1897 when the electron was discovered, through 1911 with the discovery of the proton, to 1932 when the neutron was discovered. During all those years of physicists trying to understand the atom and its properties, splitting the uranium atom was proving most difficult. The key was when James Chadwick discovered the neutron in 1932. In December 1938, the German scientist, Otto Hahn, bombarded uranium with slow-moving neutrons and became the first person to split the uranium nucleus. It was the slow-moving part that was important because a fast-moving neutron would simply bounce off the uranium nucleus, or at least would not be captured.

I should explain about the difference between fast and slow-moving neutrons. When a nucleus is split, it releases two or more fast-moving neutrons, which need to be slowed to be captured by another nucleus to continue the reaction. That is, its speed needs to be moderated, and this is achieved by a moderator which does not absorb the neutron but bounces it around and thereby slows it so that it can be captured. The moderator can be graphite, beryllium or water – either ordinary (light) water or heavy water.

Some years before Hahn split the uranium nucleus, the Hungarian physicist Leo Szilard realised that if two or more neutrons are released when a nucleus is split, then a chain reaction would be possible. Fission occurs when the nucleus of a U-235 atom is hit by a slow-moving neutron, which enters the nucleus and converts it to U-236 (since it now contains one more neutron). The U-236 nucleus then splits to form two other nuclei at about half way up the table of nuclides, and releases two or more fresh neutrons. One of those neutrons hits another U-235 atom to continue the chain reaction. The process of splitting is known as fission, so I have been known to describe the two new nuclei as fission chips.

Some of the released neutrons hit the U-238 atoms and are absorbed, so changing to U-239. Within less than half an hour, the U-239 decays by another process to become Neptunium-239 which, within a couple of days, decays to become Plutonium-239. And that is what was wanted. As the uranium fuel remains in the reactor core that plutonium absorbs further neutrons and becomes Pu-240, or Pu-241, or higher.

Today, everybody has heard of plutonium, but most would not know that there are different kinds. Many will tell you that plutonium lasts for 24,000 years, which in itself is incorrect. That is approximately the half-life of Pu-239, the period during which half of the original plutonium has decayed to become another element – hence the term ‘half-life’. Another isotope has a half-life of 14 years, and yet another has a half-life of 373,000 years.

All of the isotopes that are radioactive are constantly changing. They are subject to radioactive decay and while they might start out as a pure element, they are gradually becoming a mixture of elements depending on the mode of decay. As an example, let me explain the radioactive decay of Plutonium-239. That isotope has 94 protons and 145 neutrons in its nucleus: 94 + 145 = 239. It decays by the emission of alpha particles – the emission of the nuclei of the helium atom which contains two protons and two neutrons. If you subtract two from both the number of protons and the number of neutrons of the Pu-239 nucleus, you finish with 92 protons and 143 neutrons – which gives you U-235. Plutonium-239 has a half-life of 24,400 years and in that time, half of the plutonium has decayed to become uranium. Just to give that some context, remember that only 25,000 years ago, Neanderthals roamed this earth, and boy have we changed since they left!

That is just about all the atomic jargon needed to read and understand this book. You might not believe me, but if you have absorbed the above, you probably have a better understanding of nuclear physics than some whose job it was to oversee the latter phase of the Maralinga project.

Chapter Two – The Learning Curve

August 1945 and I was in class at my grammar school at Mile End Lane in Stockport when bells rang throughout the school. We all knew that signified the end of the war, which was welcomed by cheering from every classroom. Some would say it was a year to remember as it marked one of history’s turning points. It was the year when I, in common with almost everybody else on the planet, first heard anything about nuclear explosions.

We schoolboys (in those days it was an all-male school) heard that two cities in Japan had been destroyed, each in an horrendous way by a single bomb. We did not know that there were two types of atomic bomb, and both had been developed in something called the Manhattan Project. None of us knew anything about that project. Most people would not have known anything about uranium and would have been puzzled by the term enriched uranium. And I doubt if more than a handful had heard of plutonium. Yet the first of those bombs, dropped on Hiroshima, was made from enriched uranium, and the second, which destroyed Nagasaki, employed plutonium. We had no knowledge of the fact that there had been a test explosion of the Nagasaki type of bomb at Alamogordo in New Mexico on 16 July 1945. That was the first nuclear explosion, code-named Trinity.

At that age, I could not foresee that one day I would be a member of a team working on plans to build an atomic power station in Australia, which would in fact be part of a larger project of Australia’s second attempt to acquire nuclear weapons. Nor could I imagine that I would be the key person in a project to clean up the aftermath of testing nuclear bombs in a far distant country on the other side of the world. I could not have envisaged that I would stand at ground zero at Hiroshima, or at ground zero of nine atomic explosions in Australia, and several in the USA, both above ground and below ground. Neither could I expect to walk over a vast area of the Australian outback which, thanks to British atomic tests, is still contaminated with plutonium. And I could not have imagined my time working, as a contractor, within the murky world of the Australian public service.

Before any of that could eventuate, I had to complete my education, become qualified in some field or other and build up my experience in that field. I did not know that my future career would start in the peaceful use of nuclear power, but would end at an atomic bomb test site in a far distant country.

When nuclear weapons were introduced to the world, I was one of the millions who had no idea that something as innocent, insignificant and invisible as a neutron could make metals violently explode. In any case, most people, including me, would not have known what a neutron was – it had been discovered only a year before I was born.

I would have been in my third year at grammar school when our maths teacher mentioned somebody called Einstein and said that you have to be able to think in many dimensions to begin to understand him. I could only think of three dimensions – I hadn’t even thought of the dimension of time. Had our lesson been a few years earlier and in Germany, our teacher would have been hauled off by the Gestapo for teaching Jewish science. As for me, I knew nothing about Einstein and his famous formula equating energy and mass, yet that was to be the basis for my future career in the nuclear industry.

When the war ended and the bombing of those two Japanese cities was reported, I remember seeing photos of the destruction, and newspapers depicted what would happen to cities such as London, Birmingham or Manchester should they be hit by an atomic bomb. Rather too frightening to contemplate.

While our political leaders might have had some knowledge of what was happening in Germany, the general public did not know that a Nobel Laureate theoretical physicist named Werner Heisenberg had been trying to develop a nuclear weapon. When Germany overran Belgium in May 1940, they seized a large stockpile of uranium ore. Britain also knew that Germany was attempting to build a nuclear reactor and that could eventually lead to a new kind of weapon, now known as an atomic bomb.

The Australian government at the end of the war was under the prime ministership of Ben Chifley. He was naturally concerned for national security and looked to Britain and the Empire for assistance. In fact, defence of the Empire was predicated on the potential deployment of nuclear weapons. This defence of the Empire – Britain, Australia, Canada, South Africa and New Zealand, would cause problems for Britain and Australia thanks to American resistance.

While I was getting to grips with my studies at school, somebody called Christopher Hinton was appointed Deputy Controller of Production – Atomic Energy, for the British government. That was in 1946, and he was given the task of producing sufficient plutonium to make an atomic bomb, and have it ready by the beginning of 1952. Since plutonium does not occur in nature, his first problem was how to make it. He gathered a team around him and built two reactors, specifically for the purpose, at a place called Windscale on the Cumbrian coast in the north-west of England. He also had to construct a chemical plant to separate the plutonium from the reactor fuel.

At intervals in this book, I relate how I have seen something and had no idea what it was, and then years later, I learned what it was and how it was used. An early example was when we children watched as aircraft flew over our countryside in Cheshire and dropped strips of aluminium foil. We collected as many strips as we could, having no idea at all as to what we were collecting. It was many years later when I learned that we had been witnessing preparations for D-Day, the invasion of France by Allied forces. The foil, known as Window by the British and Chaff by the Americans, was dropped from bomber aircraft to confuse German radar.

When I left school and started work, I had no idea what I wanted to do for a career, but my first employment was with an engineering firm in Stockport called Crossley Motors which used to be well known for the cars and other vehicles that it designed and built. So it was that I started my path to becoming a nuclear engineer in an industry far removed from the atomic world, but my first tenuous links to the nuclear industry were experienced during my time with the company when one of the men, operating a centre lathe, had to turn some small caps, about an inch diameter and made from some new type of metal – an alloy of magnesium and aluminium. They were end caps for fuel elements in a nuclear power station.

My second connection was while I was making bevel gears and another man worked on some hollow ‘boxes’ made from aluminium. He machined hundreds of those mysterious boxes, and others assembled what were now recognised as gear boxes with an impeller to move some gas or other fluid. It was years later when I found that they were at the heart of uranium enrichment as I saw lines of them in a huge factory.

All the time that I was learning my trade with a view to later becoming an engineer, somebody was in Australia letting off atomic bombs, of which I knew nothing. Not a word. Or if I did hear of it, I immediately forgot it, or dismissed it since it was on the other side of the world. While I was making drawings of jigs or tools in the drawing office, or operating a lathe in the tool room, or perhaps even turning out bevel gears in the workshop, somebody called William Penney exploded an atomic bomb aboard a ten years-old British warship in a lagoon in the Monte Bello islands off the north-west