Newspapers reporting “radiation leak” – that may or may not actually exist.
Some anti-nuclear folks here in Australia have quickly jumped on to this recent media report.
“A minor contamination involving the chemical beryllium was reported on 2 November 2007 at the Defence National Storage and Distribution Centre, at Moorebank in New South Wales,” the statement said.
“It is believed the contamination occurred as a result of packaging of damaged equipment items returning from the Middle East.”
Everyone at the site was evacuated and firefighters were called in to assess the hazard.
Hazardous materials experts detected “two low-level positive indicators for the presence of beryllium”.
The area was declared safe on November 6.
“Occupational health and safety briefings have been provided to the small number of staff that may have been exposed and counselling is available on request.
“Those personnel exposed to the site will undergo thorough on-site medical testing.
“An investigation is currently underway to determine the immediate and follow-on action required to prevent a reoccurrence.”
It was not immediately clear why defence waited six days to issue the statement.
Now – my question is how exactly the mainstream media can get from “A minor contamination involving the chemical beryllium” to a “radiation leak”.
Essentially all Beryllium in nature consists of the stable isotope Beryllium-9 – Beryllium, in general, is not radioactive, unless a sample of radioactive 10Be, for example, which has been produced in a particle accelerator or reactor, is being considered. Of all the the other isotopes, only Beryllium-7 and Beryllium-10, with half-lives of 53.2 days and 1.51 million years respectively, have long enough half-lives to be of radiological significance – the half-lives of all other isotopes are extremely short, anywhere from 13.8 seconds for Be-11 down to 92.6 keV for Be-6 (The “lifetimes” of such extremely unstable nuclear states, which are only of academic interest to experimental physicists, are usually expressed in terms of a decay width, with units of energy – to convert to units of time, t = h-bar / E, where h-bar is the reduced Planck constant, which gives us, in this case, something of the order of 10^-21 seconds.)
Beryllium is a toxic metal – with the potential to cause severe health impacts if it is inhaled. As it is a stable, solid material with a very low atomic number, Beryllium is very useful as a neutron moderator – and as a neutron reflector. It has found applications in nuclear weapons technology for this reason, as well as nuclear reactors and similar technologies, occasionally. As a very lightweight, thermally stable metal, it is also extensively used in high-performance components for rocket engines, gyroscopes, satellites and missiles – clearly, it is not unheard of to find Beryllium metal components in military technologies.
10Be is a naturally occuring, cosmogenic radionuclide, and is one of the more common radioactive isotopes, along with 14C, produced in the atmosphere by cosmic ray spallation of oxygen and nitrogen. Cosmogenic 10Be accumulates at the soil surface, where its relatively long half-life of 1.51 million years permits a long residence time before it decays.
Studies of 10Be and its daughter products have been used to examine soil erosion, soil formation from regolith, the development of lateritic soils, as well as variations in solar activity and the age of ice cores.
However, radioactive 10Be or 7Be are not employed in any technological, industrial or practical applications, and these radionuclides are not manufactured, except for very small scale use in experimental physics, perhaps, or in biochemistry, where 7Be has been used as a biochemical tracer.
There was significant media attention and controversy earlier this year, after Tritium contamination was found at a workshop used for the repair of electronic instruments, where numerous devices such as compasses or gunsights containing Tritium light sources were handled, at an Australian Army barracks.
However, I find it hard to believe that any journalist could get Tritium confused with Beryllium, without willingly making stuff up. It should be noted that the phrase quoted from the official Department of Defence media release does not make any mention of radioactivity at all.
The other thing I considered is that we could be dealing with a neutron source, containing beryllium mixed with a alpha-emitting radioactive isotope, such as 241Am – although, in this case, it is not the beryllium that is radioactive, such sources are always sealed sources, and I can’t think of why they’d be used by the defence force in the Middle East – possibly in moisture gauges for civil engineering?
I await more information on this issue – hopefully I will be able to find the DOD’s media release. Until then, I’m strongly inclined to believe that this is little more than a badly written, unscruplous piece of journalism design to incite further hysteria about nuclear technologies and keep people scared of radioactivity, for the sake of someone’s political agendas.
Beryllium optics and mirrors are commonly encountered in high-performance optical systems, particularly operating in the infra red spectrum – Thermal cameras, FLIR systems, Space Telescopes, and IR-sensing devices for military applications are amongst the largest applications of such optical components. Optical systems operating in the IR spectrum often use Thorium Fluoride as a coating material on the optical components.
I can confirm that the PAVETACK FLIR pod used on the F-4 and F-111 fighters, as well as the FLIR system used on the F-18, uses beryllium optics, and that the aperture windows on these systems have a Thorium(IV) Fluoride coating. Whilst it is only a tiny bit of Thorium, presumably the material can be released if the aperture window is broken, and this has been known to occur, for example, as a result of bird strikes on the aircraft’s FLIR pod.
It is possible that a damaged FLIR head, or Mirror Control Assembly from the PAVETACK, could be contaminated with Thorium – and toxic Beryllium too – but clearly this is of very minimal risk, and not of any risk to people, aside from people who are handling it.
In that regard, I wouldn’t consider it any different to handling Thorium-containing welding rods, which are routinely used and are available to the public, or the use of camera optics with Thorium oxide in the glass – again, these are a common item in public circles.
I cannot confirm that this was the actual material involved in this incident that is being reported, but it sounds like the most plausible explanation to me – and even in the event that a thorium fluoride coated optical component was involved, it’s a far cry from a “radiation leak” – do we cry “radiation leak” in the press every time somebody uses a TIG welding rod, or drops an old camera lens? I think not.