Direct exposure of polychlorinated biphenyls to the radiation field of used nuclear fuel.

[NNadir]

Halogenated organic molecules, both those being actively produced as well as those which represent legacy production represent one of the most important (and dangerous) environmental issues today.

For many years, it was dangerous to eat bluefish caught from the Hudson River because of discharges over many decades of the mid 20th century of PCB (polychlorinated biphenyls) from the General Electric plants (for capacitor manufacture) at Hudson Falls and Fort Edward.

Millions, hundreds of millions of transformers were manufactured which contained PCB's.

In 2003 it was reported by scientists at the Department of Materials and Nuclear Engineering, University of Maryland, College Park that...

...about 125 million transformers containing PCBs were in use as of 1999, based on required user information data compiled by the United States Environmental Protection Agency (EPA) Office of Pollution Prevention and Toxics (1).Although there were, on average, about 25 000 high-level concentration (>500 ?g g^-1) PCB transformers disposed of per year from 1990 to 1994 (2), the current U.S. inventory has remained essentially constant since 1988. This is primarily due to three factors. First, there are only four incinerator disposal facilities for high-concentration PCB-laden oils left in the United States. Second, the disposal costs are continuing to increase as access to facilities becomes more limited. Last, there are no regulatory requirements or incentives for early (i.e., before end-of-life) PCB disposal.

(Source: Cynthia G. Jones ,† Joseph Silverman , and Mohamad Al-Sheikhly *, Environ. Sci. Technol., 2003, 37 (24), pp 5773–5777

Because of the unusual strength of carbon-halogen bonds, particular those of fluorine, chlorine, and, in aromatic compounds utilized widely until recently as flame retardants, bromine, consider energy is required to break these bonds in order to mineralize (convert to salts like sodium fluoride, sodium chloride...etc and carbon dioxide) these compounds.

The best and in many cases the only way to break these bonds is radiolysis, and the higher the energy of the radiation, the better. As a practical matter, gamma rays, x-rays, and to a lesser extent UV radiation is required.

This was widely understood by previous generations, who explored this approach for quite some time, but has been forgotten because of fear and stupidity about radiation and its potential to save lives other than by being the largest source of climate change gas free energy ever developed.

While searching the scientific literature recently on the subject of the radiolysis of organohalogens I came across a cool paper from 1993 where scientists at the Idaho Engineering Laboratory directly exposed PCB's to the intense radiation field of used nuclear fuel directly from a reactor.

The widespread environmental distribution of polychlorinated biphenyls (PCBs) has been well documented(1-3). The persistence of PCBs in the environment, coupled with their apparent toxicity ( I ) , led the United States to pass the Toxic Substances Control Act (TSCA)in 1976. The current TSCA approved methods for destroying PCBs are high-temperature incineration or high-efficiency boilers (1). Destruction of PCBs by incineration, however, is meeting with increasing public opposition. The public's fear of incomplete incineration and the possible formation of highly toxic dioxins and dibenzofurans, if the combustion temperature is not held sufficiently high, has significantly reduced the general acceptance of this technique. Many PCB-containing solvents are valuable products in the absence of PCB contamination.

What is needed is a process that would degrade the PCBs and allow the solvent to be recycled rather than destroyed. Towards this end, radiolysis offers many attractive features such as (a) minimization of gaseous and particulate effluents, (b) potential of recovering the bulk solvent for recycling, (c) ability to verify that the hazardous constituents have been reduced to acceptable limits, and (d) possibility of in situ destruction in selected applications due to the highly penetrating nature of ?-rays.

Now for the fun part of the paper which surprised even me.

Irradiations. Samples were ?-rays irradiated using spent nuclear fuel at the Advanced Test Reactor (ATR) at the Idaho National Engineering Laboratory. Spent nuclear fuel is an excellent source of y-rays with an average kinetic energy of 700 keV. Depleted fuel elements from the reactor are stored vertically in grids in an adjacent canal under approximately 6.5 m of water. A dry tube extends from the surface of the water into the grid, and the fuel elements are placed around it. Proper positioning of the fuel elements around the dry tube allows for the selection of dose rates up to 25 Gy h^-1. PCB samples were contained in 1.5-mL glass septum vials…

Environ. Sci. Technol., 1994, 28 (12), pp 2191–2196

Although in this experiment, the PCB's were completely and totally mineralized, it's not something I would recommend industrially, since used nuclear fuel is also a neutron source, and on an industrial scale, chlorine might be transformed into ³⁶Cl which is radioactive and would only prove useful for tracer experiments.

This said, among many the fission products, ¹³⁷Cs, is an excellent source of ?-rays. In particular, certain titanates, which have been used as ion exchange materials in removing ¹³⁷Cs from water are excellent materials for the degradation of water supplies contaminated with organohalogens and other organic pollutants.

Were we to get over the stupid enterprise of waiting like D'Estragnon for Godot, for the grand so called "renewable energy" industry to produce 100% of the world's energy, even though trillions of dollars and decades of effort and cheering have not caused it to produce 5% of the world's energy, we would be reprocessing used nuclear fuels, collecting the very valuable materials therein, including highly radioactive materials like ¹³⁷Cs to solve problems about which, including but not limited to climate change, we are content to do nothing.

Esoteric, but interesting.

Have a nice Sunday afternoon.

[Vogon_Glory]

1. Thanks for posting this

PCB contamination does concern those of us who care about clean waterways during and after the time of Thump and his horrible environmental policies. I find it amusing that one pollutant (and a pollutant we're stuck with, even if we gave in to anti-nuclear Pollyanna-ism and shut down each and every fission reactor tomorrow morning) can solve the PCB problem for us and our posterity.

[NNadir]

2. Thank you for your comment. Persistent organic pollutants (POP), particularly halogenated cases...

...are one of the most serious issues before humanity, not only in waterways, but in soils, the tissues of living things - including but hardly limited to human tissues and fluids (including breast milk), and the atmosphere, where some of them, including some still being manufactured on a vast scale - SF₆, albeit a persistent inorganic pollutant, comes to mind - are very potent greenhouse gases.

The key to solving this problem - and I've been studying it a long time - is to recognize that so called "nuclear waste" is not "waste" at all, but that fission products - especially fission products - are valuable materials that may prove essential to remediation of some very serious widely distributed pollutants.

In 30 years of study of the issue, I have convinced myself that there are zero constituents of used nuclear fuel that cannot be utilized, both those that are radioactive, and those which have decayed to non-radioactive stable elements.

It breaks my heart that these materials have not been isolated, and that, for one example, ¹³⁷Cs is being allowed to decay in isolated sealed containers instead of being placed in solid matrices like synthetic pollucite or - even better - cesium aluminum titanates to destroy, at the very least, via heat driven convection, atmospheric SF₆ and the related very problematic N₂O, which is the third most important greenhouse gas after methane and carbon dioxide, and is also a very potent ozone depleting agent.

Both SF₆ and N₂O have been utilized in devices known as Frick dosimeters which measure radiation by following the radiolytic decomposition of these gases. This represents a huge opportunity to industrialize atmospheric clean up, particularly in the troposphere in which we live. The destruction of N₂O at ground level would have the added benefit of destroying ground level ozone. Ozone is a wonderful thing in the stratosphere, but down here it a serious pollutant, and is a factor in the destruction of the seven million lives lost each year to air pollution.

Thanks again.