The alleged problem of nuclear “waste” is perhaps the most comically overblown aspect of the entire debate over nuclear energy. You would never know it from the usual media reports, but the “waste” product of nuclear reactors—that is to say, the used or spent fuel—actually comprises a comparatively minuscule amount of material. A few weeks ago, I pointed out that the accumulation of used fuel at Canadian nuclear power reactor sites is analogous to each Canadian household producing a gram of garbage per day. That is an almost laughably small amount of waste, and it obviously does not represent any significant problem.
The entire Canadian nuclear power industry has over its 40+ year history produced around 40,000 (that’s forty thousand) metric tons of used fuel. By contrast, a single 1,000-megawatt natural gas-fired generator produces around 4 million tons of carbon dioxide (CO2) in a single year.
In other words:
A single 1,000 MW gas-fired generator produces literally one thousand times as much waste in a single year as all of Canada’s nuclear reactors have produced in more than 40 years.
So why are we wringing our hands over an easily managed nuclear byproduct, while gas-fired plants are busy dumping literally millions of tons of bona fide waste into our air?
While it represents a comparatively tiny amount of material, used nuclear fuel is itself an extremely valuable resource, containing lots of still-usable fuel for future power generation. It also contains isotopes, or sub-groups within chemical elements, that are so valuable to society that it is almost impossible to imagine modern life without them.
These isotopes include significant amounts of strontium-90 (Sr-90) and cesium-137 (Cs-137), which are both fission products, i.e., the lighter fragments of uranium atoms that have split apart in the reactor to produce the heat that makes electricity.
Both Sr-90 and Cs-137 have a bad reputation out in media la-la land, where scary stories are the stock in trade. But among people who work with them every day, these isotopes are extremely valuable and in many cases indispensable life-savers.
For example, Sr-90 is what’s called a beta-emitter, meaning that when it disintegrates it does so by firing out a high-energy electron called a beta particle. This isotope’s unique mass means that the emitted beta particle has a certain energy, which interacts with certain other materials, like the metal in helicopter rotor blades, in a very definite way. This makes Sr-90 a highly effective active ingredient in devices that detect fatigue in rotor blades while the helicopter is in flight. Such information is critical to helicopter pilots and passengers.
Cs-137 is similarly indispensable in other life-or-death situations. When it decays, Cs-137 (actually its daughter isotope barium-137) gives off gamma rays of a certain energy. That energy is suitable for sterilizing blood and blood products. Gamma sterilization is the only way of reducing the chance that certain recipients of blood transfusions—including infants and immuno-deficient patients—will catch a transfusion-related disease that is almost always fatal. There are around 100 Cs-137-loaded blood irradiators in Canada. They save lives.
Sr-90 also creates heat as it disintegrates. That is because those beta particles collide with other material. The collisions generate heat. If you have a lot of Sr-90, you can generate a lot of heat.
What could you use that heat for? I suggested in “Inuvik running out of gas” that Sr-90 could be used to keep water from freezing in northern communities, where water freezing presents a major problem. Sr-90 could also be used to keep sewage warm, thereby promoting anaerobic digestion of harmful sewage material. Anaerobic digestion is most efficient when the digested material is around 50 °C: a difficult temperature to maintain in the arctic.
Remote arctic communities are not the only ones that could benefit from the use of Sr-90. Many if not most communities along Canada’s three ocean coasts dump untreated sewage directly into the sea. This is supposed to stop, but it is very expensive to build and maintain sewage treatment systems, and more so when you have to worry about freezing.
A system that incorporates both Sr-90 and Cs-137 has been proposed for such communities. Sr-90 would keep sewage from freezing and at the optimal temperature for anaerobic digestion. Cs-137’s gamma rays would destroy the remaining pathogens in the sludge.
Sr-90 and Cs-137 are among the most energetic of the isotopes in used nuclear fuel that have half-lives of concern (Sr-90 has a half-life of 29 years; Cs-137 30 years). Those half-lives also make these isotopes extremely valuable. If they were separated from used fuel and used in the ways just described, that would be an immeasurable public health benefit to Canada. Imagine a thirty-year source of heat and sterilization.
Cs-137 gamma rays could also be used to kill microbes in food (see article). Currently there is a major beef recall in Canada. Such episodes could be made nearly obsolete if more food producers and retailers woke up to the benefits of gamma-ray treatment of food. Producers and retailers have tried before to achieve greater uptake of gamma treatment, only to be rebuffed by public authorities with an aversion to criticism—even though that criticism comes from loud and uninformed anti-nuclear fearmongers. What a shame to see authorities cave in to that kind of nonsense.
With Sr-90 and Cs-137 separated from used reactor fuel, the remaining isotopes would consist mainly of unburned uranium and heavier transuranic elements including plutonium isotopes that can and do serve as fission fuel, which is by far the cleanest and most environmentally innocuous fuel for electric power generation.
A small and easily managed “nuclear waste problem” thereby becomes even smaller and more easily managed.
It’s more complex than that: the energy is indeed fixed, but is partitioned in an infinitely variable way between the electron and an electron antineutrino. The antineutrino is very hard to detect. In travelling a few millimetres or centimetres through a medium that can turn its energy into light, a neutrino is likely to lose no energy and make no light.
Since this is also true when it travels millions of metres through rock, and some of the daughters of uranium are beta emitters, neutrino detection, difficult though it is, is being used to answer the question, How much uranium is in the Earth (freely downloadable paper).
Thanks for the clarification and for the link to the Cornell piece. Neutrinos are a pretty interesting subject. But it is the energy from the beta particle that makes beta emitters valuable, no? If the energy is partitioned between the electron and the antineutrino, how is it that the electron leaves such a precise signature?
Reading that PPT document, I don’t see that the strontium-90’s beta rays are doing anything very precise. When there is pressure within a helicopter blade, it holds a thin metal shield between the source and the detector, and when there isn’t, the beta rays get through.
That is refreshing and enlightening Steve. Thanks. Even as an advocate of nuclear energy I would not have guessed it was such a staggering difference between what waste is left behind.
Maybe somebody should tell Justin Trudeau.
Rick, thanks — “staggering” is an excellent way to describe it. The fact that the public sees it exactly the other way round is testament both to the tenacity of the anti-nukes who have dedicated themselves to misrepresenting and to the complacence of the industry in not countering the misrepresentations.
There is a staggering difference between conventional, bona fide, garbage and nuclear “waste.” The former is enormous; the latter is tiny.
I like the creative suggestions for strontium-90 (Sr-90) and cesium-137 (Cs-137) The sewage treatment is a very interesting and needed solution.
There is a possibility of transmuting Strontium into molybdenum using low energy nuclear reactions. Do you think this molybdenum can be used to make technicium 99m for medical isotopes?
Strontium, atomic number 38, into molybdenum, atomic number 42? I have not heard of this process. Do you have a link to some info on it?
There are a lot of other valuable elements in the fission product matrix, like the entire Lanthanide series, most of which become essentially non-radioacrive in less than 50 years. Lots of semi-precious metals, too.
Les, thanks — yes, promethium-147 is in that series and is another relatively high-yield product which is both extremely valuable and relatively short-lived (half life of around 3.5 years).
oh cool. tell that to the people in fukushima an chernobyl. they will be happy.
Jennico, the people in Fukushima would be happy if nobody had died during the needless evacuation. Here we are 574 days since the meltdowns, and there have been exactly zero people who have even gone to the hospital because of radiation.
Come to think of it, the people in Fukushima would be happy if people like you didn’t deliberately spread fear based on junk science. Then their weak and incompetent government wouldn’t have felt it necessary to evacuate all the senior citizens, many of whom died during the evacuation.
There’s also the use of am241 in smoke detectors. That gets really useful because am241 is one of the actually long lived component of nuclear waste, that neither can be reused in new fuel like Pu239 or rests of U235, nor will be gone in 300 years.
Am-241 and the other trace actinides will fission in a fast neutron spectrum, so if you can incorporate it into FBR fuel you can eliminate it. Fast-spectrum reactors have a much lower rate of non-fission neutron captures in Pu, so they produce fewer actinides themselves.
There is a slight possibility of am241 being able to used for weapons.For smoke detectors we will be needing only a few grams, the rest can be made for nuclear weapons, though it is not straight forward.