The Koeberg nuclear plant near Cape Town requires about thirty tons of uranium fuel per year.  Unlike a fuel such as coal, this uranium is not burnt up.  It undergoes a nuclear reaction, which transforms it into other elements, some of which are highly radioactive. Burning or any other chemical process does not reduce the radioactivity.

That means that over thirty tons of spent nuclear fuel (SNF) are removed from the reactors each year.  So far over a million kilograms of this SNF (over 2000 fuel elements)  have accumulated since Koeberg began operating in 1984.

Let’s get technical for a moment…
When SNF is removed from the reactor, it is extremely radioactive, so much so that standing next to it for a few seconds would result in a lethal dose, with death occurring a few days later.  This means it must be handled remotely, usually by robotic arms and lifts.

It also gives off heat, at a rate of about 5kW per fuel element, which means each element could boil a home hot water cylinder in about two hours.  If this SNF is left out of water, it will heat up until it melts and ignites the flammable zirconium cladding around the fuel elements. This can result in molten uranium from multiple fuel elements pooling, causing what physicists call criticality, or is commonly called a nuclear explosion. This means the SNF must be kept under water which is constantly circulated to prevent it boiling away.

These two factors combined make dealing with this waste “one of the most complex challenges facing nuclear technological development” [1] according to scientists.

At the moment, high level nuclear waste is being produced worldwide faster than disposal sites are being designed, let alone built.

A timeline…
The history of this waste in South Africa is unfortunately not encouraging. If past performance is any indication of future performance, we may be in trouble…

1975-1979	Koeberg design is finalised, includes space to store 5 years of SNF
1980-1984	Koeberg first starts producing power
1985-1990	Space in the cooling ponds runs out
1991-1995	Triple racking used to squeeze more waste into the ponds
1995-1999	Promulgation of the National Radioactive Waste Disposal Institute (NRWDI)
2000-2004	‘Temporary measures’ used during 2000 refuelling to cater for lack of cooling pond space
2005-2009	Promulgation of the NRWDI in 2009
2010-2014	Minister announces launch of NRWDI on 1st April 2014
2015	NRWDI investigated by Minister for mismanagement
2016	Minister of Energy states in parliament on 8 April that the “NRWDI is not yet operational”

It’s not too clear what they are accused of mismanaging in 2015, as they are still not operational. The waste disposal problem was meant to be solved 5 years after the plant started up, and so is now 26 years behind schedule.

Some common nonsense….
The nuclear industry has three common tactics to attempt to minimise the problem of this waste:

1. One day we will find a use for it! It’s really a resource!
2. Its not that much! It would fit into a block 6m x 6m x 6m.
3. Soon we will be using breeder reactors [2] that will just eat up all that waste we are producing now!

Unfortunately, these are all really lame, and each of these is dealt with in turn below:

1. We might not find a use for it and future generations may be saddled with an expensive problem with no good solution. All scientific studies to date have concluded that reprocessing is not economically viable.  It also is the way to isolate plutonium, which is the ideal element to use in a nuclear bomb, so it is generally considered a very bad idea to allow development of reprocessing technology and facilities under any circumstances.
2. A detail this point omits is that If anyone was stupid enough to put this waste in such a block, it would achieve criticality, and result in a catastrophic nuclear explosion. I most recently heard this nonsense spouted by an Eskom employee at a public meeting in Kenilworth (run by GIBB consulting, who unsurprisingly omitted this from the minutes they released).
3. Breeder reactors are not popular, and the experience to date has not been good. Monju is a breeder reactor in Japan which was built at the same time as Koeberg, and has so far generated electricity for just one hour, due to a series of failures and accidents.  Less than 1% of nuclear power reactors in the world are breeders (none of them in the West), and with good reason, as there are significant engineering problems with regard to the coolant.

Why don’t we hear more about this?
Unfortunately, the handling of nuclear waste is a complex issue and not well suited to fund raising campaigns, and so has been largely ignored by NGOs in South Africa.

In other countries the picture is very different. In Sweden an NGO has been formed with the sole mandate of looking at the high level nuclear waste disposal issue.  The Office for Nuclear Waste Review (Miljöorganisationernas kärnavfallsgranskning, or MKG) functions as a critical, science based watchdog which examines the plans for nuclear waste as formulated by the cosy partnership of the large nuclear industry and government bodies.  MKG also contributes to scientific studies about waste disposal possibilities, and participates in international conferences on the subject.

This contrasts starkly with South Africa, where no site for disposal has been identified, no disposal technologies have been evaluated and the governmental body meant to have been accepting high level waste since 1991 is not yet operational.

In conclusion…
We are leaving over a million kilograms of dangerously radioactive waste to future generations as part of our legacy. Good luck guys!

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References

1. DEVELOPING A FRAMEWORK FOR EVALUATING SPENT NUCLEAR FUEL MANAGEMENT OPTIONS FOR SOUTH AFRICA, The South African Journal of Industrial Engineering, V.G. Twala1,  T. Auf der Heyde , P.J. Bredell, and L. Pretorius
2. How do fast breeder reactors differ from regular nuclear power plants? Scientific American, P. Andrew Karam
3. Swedish NGO Office for Nuclear Waste Review