Regardless of whether such waste negatively impacts the environment or not, it is generally agreed that nuclear waste does not belong in the ocean.
By Mark Pan
Into the ocean it goes
There were several methods proposed on how to manage nuclear waste: underground storage, reprocessing, even so far as launching it into space*. However, prior to 1993, one of the most cost-effective methods was to simply discard waste into the oceans: the first dumping operation was 80 kilometres off the coast of California in 1946. From then on, countries such as the Soviet Union, the UK, and France joined in on ocean disposal, and this continued on: in total, 13 countries have disposed of nuclear waste in the ocean.
In 1972 the London Convention for the Prevention of Marine Pollution by Dumping of Waste and Other Matter (or the London Dumping Convention, as everyone refers to it) set forth a precedent which came into effect in 1975, prohibiting the dumping of high-level radioactive waste. This includes irradiated (exposed to radiation) nuclear fuel, and any waste material exceeding the following concentrations: 5×10-5 TBq/kg (terabecquerel/kilogram) of alpha radiation emitters; 2×10-2 TBq/kg of beta or gamma radiation emitters with half lives lasting longer than 1 year; and 3 TBq/kg of tritium or beta/gamma radiation emitters with half lives less than 1 year.
Albeit the London Dumping Convention outlawed the dumping of high-level nuclear waste, it did not prohibit the dumping of nuclear waste in general: low-level waste disposal was still permitted with a permit. Dumping continued until 1993, when a Russian vessel was documented pumping liquid nuclear waste into the Sea of Japan, sparking international outrage.
This sparked a resolution at the reconvening 1993 London Dumping Convention which was approved by all the member countries, outlawing any nuclear dumping by means of ocean disposal. Between the 47 years, approximately 63 PBq (63 petabecquerels, or 63 quadrillion becquerels, or 6.3×1016 Bq) of nuclear waste has been disposed of in the oceans, nearly 99% of it being beta/gamma radiation emitting material. 1993 being merely 28 years ago, it is startling how only recently have we started to realize that disposing such waste into the ocean wasn’t perhaps the best solution.
The environmental impact
So how exactly did the dumping effect the oceans? The consensus is mixed: some believe that the ocean is fully capable of diluting the radioactive waste, whereas others believe that the waste will tend to linger in the general vicinity of the dumping area. Several studies and expeditions have been conducted to measure the extent of any effects in areas where dumping had historically taken place, including the Atlantic, Pacific and Arctic Oceans, in an attempt to understand the impact of such activities.
What the present looks like
Currently, nuclear waste is stored on land, and there are stricter and more stringent precautions towards the handling of such waste than there was in the 20th century. The majority of nuclear waste produced is low-level to intermediate-level waste (approximately 97%), with a fraction of it being high-level waste: thus, such waste can be left in storage until it has decayed into a safer state for regular trash disposal.
Several technologies, including vitrification (the process of combining nuclear waste with glass, thus creating a more manageable solid), seem promising and it is imperative that we develop a solution to dispose of the waste, preferably not involving our oceans.
*In case you were wondering, no, shooting our nuclear waste into space simply isn’t feasible. Launching rockets is incredibly expensive, and rockets have a limited payload capacity. Furthermore, rocket failure would result in a catastrophic spewing of radioactive material into the air, which is rather bad.