Nuke Software Topics

[Luz Ignasiak]

Ithought that nuclear power, because of the existence of immeasurably long-lived radioactive waste, simply had risks way above and beyond any other energy form. In this light it was entirely reasonable to reject nuclear power, period. The thinking behind it is quite startling when you spell it out loud:

The Finnish Radiation Safety Authority (STUK) assessed several safety evaluations during the preparations for the Onkalo nuclear waste repository in Finland. Their worst case scenario is summarised well in this excellent collection of research on nuclear safety by Janne Korhonen and his banana infographic:

Update: helpful experts have pointed out to me that there are several ways that the passive safety principles (not only with molten salt reactors type where a frozen plug melts, but other solutions that work with gravity, freely circulating air with sodium cooling etc,) exist, and even current light water reactors have incorporated several levels better safety mechanisms. More about Russian working examples of Integral Fast Reactors that can process fuel here and here. Good overviews of all different reactor types by Instititue for Energy Environmental here, as well as by a non-profit young engineer site here.

Enthusiastic about this new type of technology, and worried about the trajectory of climate change, I became more interested in questions of energy in general. Discussions on nuclear power turned out to be very tricky, however, and following the reasoning of a great number of conversation participants helped me pinpoint something I had been guilty of myself, too, all this time:

I was floored when I realized how vastly much larger were the scale of the waste problems, the seriousness of their health implications, and their radioactive contamination issues with the waste from coal.

If radiation hazard still were the number one worry, we would actually have even more reason to replace coal with nuclear. That way, we would produce less radioactive waste that spreads into the environment, and would diminish our radiation exposure.

But even so, the risks to human health from the radiation from either, nuclear or coal, are actually very very low. The really big killer is particulate air pollution from burning of fossil fuels, which kill millions every year.

We tend to think that if radioactive waste exists somewhere, its mere existence carries with it an immeasurable risk. But it is actually much harder for radioactive material to cause problems than we would imagine. For the radiation to cause any significant health problems, it needs to reach us in considerable dosage. It would have to get transported, somehow, while remaining in a highly enough concentrated form.

If we are talking about the actual long term repositories, such a scenario is so unlikely that it is more a point of scientific curiosity rather than part of a realistic risk assessment. If, say, an earthquake or a volcanic eruption would, against all odds, disrupt a previously stable location in the middle of a tectonic plate of bed rock, where the waste was stored, it could bring nuclear waste out of its containment in some form, and expose it to the elements. What would happen then?

In Gabon, West Africa, some 1.7 billion years ago, groundwater flowing through a rich deposit of uranium ore (comparable grade to the fuel used in power plants) resulted in constantly recurring 3-hour cycles of fission chain reaction during hundreds of thousands of years. These 16 natural reactor sites are estimated to have consumed five tons of Uranium 235. Many papers have been published analysing them, for instance: 2 billion year old natural analogs for nuclear waste disposal: the natural nuclear fission reactors in Gabon (Africa). It has also been covered at length in a blog on the Scientific American.

Despite the fact that these reactors and their waste were for the most part close to ground and in contact with flowing streams of ground water for the unimaginable stretch of time during which the shapes of the continents were transformed beyond recognition and life itself evolved to all its current splendor, most of the dangerous waste had traveled less than a few meters from its point of origin.

Nuclear power is the only energy form which does collect and take permanent responsibility for all its waste products. The discussion about the safety of the long term storage of nuclear waste is, quite literally, bananas: while direct exposure to high level radiation is certainly harmful, delivering that harm into the environment is far slower and less efficient than we think. The worst case scenario from a leak would amount to a person eating two extra bananas per year, for the people living directly atop that leak. In fact, even completely natural, near-ground stores of nuclear waste from natural fission reactors in West Africa, freely in contact with groundwater, have passively remained in perfect containment for soon two billion years.

UPDATE: in addition to reading more about the waste, I have now also widened my perspectives by visiting a Swiss nuclear waste interim repository and handling facility! You can read more about that in Warming My Hands on Nuclear Waste.

This article was updated June 2021, replacing the older US Department of Energy data on material requirements (as presented by Environmental Progress), with a fresh new chart from International Energy Agency on mineral requirements. More discussion on the more recent estimates on concrete, steel, and other materials by Bright New World here.

For more of my articles on climate and energy, look here. Even better idea, however, is to read the short, evidence-dense book Climate Gamble or browse the graphs in their blog. If you would like to have a discussion in the comments below, please take note of my Commenting policy. In a nutshell:

Thank you for the input! This article got longer and longer, and still I feel I could have kept adding so much important info. Especially the when where and which types of reactors, that was definitely one of those topics still lacking.

The source of waste: High-level and long-lived waste is produced when radiation damaged and incompletely used solid fuel rods are removed from the reactor and this solid fuel is not reprocessed thereafter.

The liquid-fuels are not prone to radiation damage. Fuel can be kept in the reactor as long as 40 years (Reference: ORNL-TM-7207 Denatured Molten Salt Reactor). And these liquid-fuel reactors may cost less than other advanced technologies, if given a chance to prove.

However actinides in solid fuels can be reprocessed and reused to reduce long-lived waste.

There are two types of solid-fuel reprocessing techniques. Pyroprocessing and aqueous processing (PUREX for plutonium fuel cycle & THOREX for thorium fuel cycle)

The fast reactors with integrated reprocessing employ pyro-processing which involves dissolving solid fuels in molten-salts and seperating unused fuel and minor-actinides. Pyro-processing is efficient and proven in EBR-2.

The currently employed technique is aqueous processing which is established but very inefficient and costly.

I agree that ANY type nuclear waste is more manageable than carbon-dioxide and methane from coal, hydro reservoirs or natural gas. But this should not be used as an argument against nuclear innovation and to prevent the development of pyro-processing and liquid-fuel reactors.

Actually, the reuse of nuclear waste was part of the original plan. Since, quite obviously, it is much better to use nuclear material several times, and to reduce the amount of waste that has to be deposited. Consistenty, plants like Sellafield in the UK or la Hague in France were built.

Writing from Germany, I remember that there was a breeder reactor in Kalkar in the 70s and violent fights in Bavaria (Wackersdorf) where a nuclear plant like Sellafield was about to be built in the 80s. Chernobyl stopped the latter project, and Fukushima finished off nuclear energy here some 25 years later.

Thus, today, we have a lot of nuclear waste, a large CO2 burden (since nuclear power had to be replaced by coal), wind mills all over the place, and a Green movement that wants to shut down coal power stations in due time. I am not surprised to learn that this does not look too attractive from the outside, and that clean(er) and safe(r) nuclear energy is making a comeback.

All the information I can find points toward a reduced risk, if anything, which is true already for many Gen2, and all Gen 3 and Gen 4 nuclear reactor types, as I have understood it.

Thanks again for reading. Please let me know if you have specific concerns that you can enlighten me of.

+Some of the real nuclear experts at Los Alamos or Oak Ridge have stated, no doubt correctly that a bomb could be made from this, that, or the other type of nuclear waste. I have little doubt that such real nuclear experts could do so.

But with their level of expertise, or that of anybody that could also do it, surely the way that Little Boy and Fat Man were made is easier?

A somewhat clumsy analogy would be the following:

You are asked to play a game of Russian roulette using a gun with 1000 chambers. If you win you become the richest person in the world (or whatever mythical reward you can think of). If you lose, you die. Would you play the game? Most people would answer negatively because no matter what the benefit is, the existential threat potential renders the benefit irrelevant.

Therefore I believe the atomic energy discussion shall focus on studying and quantifying the existential threat of large scale atomic energy utilization.

Your article provides some good arguments and thank you for that

[quote] This showed that the effect of exposures at Chernobyl has been an increase in cases of thyroid cancer reported in children and adolescents in Ukraine, Belarus and the four most affected regions of the Russian Federation. Up until 2005, 6,848 cases were reported in those under the age of 18 at the time of exposure. Only 15 of these proved fatal as thyroid cancer is mostly treatable.33 [unquote]

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