Admiral Hyman Rickover Descent Into Circular Nuclear Reactor Shell at Shipping Port Power Facility Shutterstock

How We Can Get Clean Energy—Is Nuclear Power Safe?

Robert Zubrin
Robert Zubrin
13 min read

Editor's note: this is the second in a three-part series on how we can get clean energy. Part I explains the relationship between Fuel and Human Progress, Part II answers the question “Is Nuclear Power Safe?” and Part III provides an answer to “What Needs to Be Done?”

A lot of fuss has been raised about nuclear power plants. Some say they emit cancer-causing radiation, that there is no way to dispose of the wastes they produce, that they are prone to catastrophic accidents, and could even be made to explode like bombs. These are serious charges. Let’s investigate them.

Routine Nuclear Power Plant Radiological Emissions

Americans measure radiation doses in units called rems or, more often, millirems (mrem), which are thousandths of a rem. Europeans use units called sieverts (1 sievert equals 100 rems). While high doses of radiation delivered over short periods can cause radiation poisoning or cancer, there is, according to the U.S. Nuclear Regulatory Commission, “no data to establish unequivocally the occurrence of cancer following exposure to low doses and dose rates—below 10,000 mrem.” Despite this scientific fact, the NRC and other international regulatory authorities insist on using what is known as the “Linear No Threshold” (LNT) method for assessing risk.

According to the LNT methodology, a low dose of radiation carries a proportional fraction of the risk of a larger dose. So, according to LNT theory, since a 1000-rem dose represents a 100 percent risk of death, then a 100-mrem dose should carry a 0.01 percent risk. If this were true, then one person would die for every 10,000 people exposed to 100 mrem. Since there are 330 million Americans and they already receive an average of 270 mrem per year, this would work out to 90,000 Americans dying every year from background radiation, a result with no relationship to reality. Fundamentally, the fallacy of the LNT theory is the same as concluding that since drinking 100 glasses of wine in an hour would kill you, drinking one glass represents a one percent risk of death. It’s quite absurd, and the regulators know it. But we are talking government regulators here, so, naturally, they use it anyway. That said, let’s look at the data.

The annual radiation doses that each American can expect to receive from both natural and artificial radiation sources are provided in the table below.

Examining the table, we see that the amount of radiation dose that members of the public receive from nuclear power plants is insignificant compared to what they receive from their own blood (which contains radioactive potassium-40), the homes they live in, the food they eat (watch out for bananas!), the medical care and air travel they enjoy, the planet on which they reside, and the universe in which their planet resides.

In fact, far from increasing the radiological exposure of the public, nuclear power plants reduce it. Coal contains radioactive constituents. Worldwide, coal-fired power stations release some 30,000 tons of radioactive radon, uranium, and thorium into the atmosphere every year. They also emit millions of tons of highly toxic chemical ash containing mercury, arsenic, and selenium, not to mention over 10 billion tons of CO2 per year. In addition to 10 million tons of CO2, a single 1,000 MWe coal-fired power plant produces 200,000 tons of ash annually and, as well as several hundreds of tons of mercury and other chemical poisons, sends some 27 tons of radioactive material—half radon, the other half uranium and thorium—right up the chimney. The amount of uranium and thorium emitted to the environment as pollution by coal-fired power plants would be more than enough to fuel every nuclear power plant in the country to produce equivalent power without any of the CO2, toxic gas, or radiological emissions.

Natural gas is much cleaner than coal, but it contains radioactive radon. Not much, to be sure, typically about 0.03 microcuries per cubic meter. But that adds up. A 1000 MWe natural gas power plant sends about 8 curies of radon into the environment every month. That’s just about the same as what the Three Mile Island nuclear power plant let loose just once—during its world-famous meltdown in March 1979!

Now, I am not saying that coal and natural gas power plants should be shut down because of their radioactive releases. But since they routinely emit more radiation than not only well-functioning nuclear power plants but also a nuke during the worst reactor accident in US history, the fervor of the authorities and activists in this area would appear to be wildly misplaced.

Nuclear Waste Disposal

One of the strangest arguments against nuclear power is the claim that there is nothing that can be done with the waste. In fact, the compact nature of the limited waste produced by nuclear energy makes it uniquely attractive. A single 1000 MWe coal-fired power plant produces about 600 tons of highly toxic waste daily, more than the entire American nuclear industry does in a year. The portion of this that is not simply sent up the stack piles up near the power plant, or is dumped somewhere else, eventually finding its way into the biosphere. Despite the clear, non-hypothetical consequences of this large-scale toxic pollution, no one is even talking about establishing a waste isolation facility for this material, because it is not remotely possible. In contrast to such an intractable problem, the disposal of nuclear waste is trivial.

It must be said: The hazards of nuclear waste disposal have been exaggerated by environmentalists, with the openly stated purpose of seeking to create a showstopper for the nuclear industry. They claim to be interested in public safety and ecological preservation. Neither claim is supportable. By protecting fossil fuel power from nuclear power, those who are anti-nuke are perpetuating environmental destruction. Regarding public safety, they are even worse. Indeed, it must perplex the rational mind that anyone can agitate, litigate, and argue with a straight face that it is better that nuclear waste be stored in hundreds of cooling ponds adjacent to reactors located near metropolitan areas all across the country than that they be gathered up and laid to rest in a government-supervised depository far removed from civilization. Yet that is what they do.

There are two excellent places to store nuclear waste: under the ocean floor or under the desert.  The US Department of Energy has opted for the desert, but the ocean solution is much simpler and cheaper. Let’s talk about that first.

The way to dispose of nuclear waste at sea works as follows: First, you glassify the waste into a water-insoluble form. Then you put it in stainless steel cans, take it out in a ship, and drop it into the mid-ocean, directly above sub-seabed sediments that have been, and will be, geologically stable for tens of millions of years. Falling through several thousand meters of water, your canisters will reach velocities that will allow them to bury themselves deep under the mud. After that, your waste is not going anywhere, and no one will ever be able to get their hands on it. Furthermore, no nomads roaming the earth after the next ice age has eliminated all records of our civilization will ever be harmed by accidentally stumbling upon it. (I mention this latter point because the protection of the public for the next 10,000 years, under all contingencies, has been made a Department of Energy nuclear waste repository requirement.)

This solution has been well known for years. Unfortunately, it has been shunned by Energy Department bureaucrats, who—despite their concern for post-Ice Age wandering cannibals—seemingly prefer a large land-based facility because it involves a much bigger budget, as well as by environmentalists who wish to prevent the problem of nuclear waste disposal from being solved. Thus, in the 1980s, the Department of Energy looked the other way and allowed Greenpeace to pressure the London Dumping Convention into banning sub-seabed disposal of nuclear waste. That ban expires in 2025. If world leaders are in any way serious about finding an alternative to fossil fuels to meet the energy needs of modern society, they will see to it that the ban is not renewed.

If the ban is not ended, that leaves the Department of Energy’s plan to put the waste under Yucca Mountain in the Nevada desert as an alternative. While wildly over-priced, the plan has been exhaustively and thoroughly vetted, and it meets the most stringent standards of public safety.

However, regardless of the fact that the project has been thoroughly analyzed—the site has been called “the most studied real estate on the planet”—environmentalist lobbying caused the Obama administration and allied lawmakers to oppose the project, and in 2011, federal funding for it was revoked. The Government Accountability Office noted that no technical or safety reasons were provided for shutting down the project. The Trump administration pledged to restart the project but did not, and the Biden administration, while claiming that it sees climate change as an “existential crisis” (i.e., one that involves the survival of humanity), has chosen not to do so, as well. Meanwhile, even with funding revoked, the government faces a liability of $15 billion, growing by another billion every two years, for failing to meet its contractual obligations to produce a nuclear waste repository.

Nuclear accidents

Nuclear accidents are certainly possible, but rare. Throughout its entire history, the world’s commercial nuclear industry has had three major accidents: Three Mile Island, Pennsylvania, in 1979; Chernobyl, Ukraine, in 1986; and at Fukushima, Japan, in 2011.

The Three Mile Island event was the only nuclear disaster in US history. It is also unique in another sense: it was the only major disaster in world history in which not a single person was killed or even injured.

There were two 843 MWe Pressurized Water Reactors (PWRs) at Three Mile Island, labeled TMI-1 and TMI-2. On March 28th, 1979, TMI-1 was shut down, but TMI-2 was operating at full power when its turbine tripped. This shut off the secondary loop water flow to the steam generator, which meant that nothing was taking away heat from the primary loop cooling the reactor. As a result, the control rods dropped into place, instantly shutting down the chain reaction. But, because the reactor had been operating for some time, the large volume of highly radioactive fission products that had built up in the core continued to generate heat via radioactive decay.

The fact that a reactor would continue to generate decay heat even after the chain reaction had been shut down was well known. According to anti-nuclear activists, it meant that, while loss of coolant would cause nuclear fission to cease, the uncooled reactor would melt itself down, with a mass of highly radioactive fission products unstoppably melting its way through the 20-cm (8 in.) thick steel pressure vessel, then through the 2.6-meter (8.6 ft) thick containment building floor, then right on down through the earth, all the way to China.

But instead of the hot fission products melting their way through the pressure vessel, the containment building, and the earth, all the way to China, they actually melted their way a couple of centimeters (about an inch) into the pressure vessel and stopped there. That was it. A billion-dollar reactor was lost, but the containment system was never even seriously challenged. A few curies of radioactive iodine-131 gas (half-life: ∼ 8 days) were vented, exposing the public in the area to about 1 mrem of radiation, equivalent to the extra dose they would have received during a five-day ski trip to Colorado instead of staying in Pennsylvania. The environmental impact was zero. If anyone was harmed, it was because the very anti-nuclear lawyers running the Nuclear Regulatory Commission decided that the accident warranted keeping the untouched TMI-1 unit shut down for the next six years, and it is estimated that the pollution emissions over that time released by the coal-fired power plants used to replace its output were probably responsible for hundreds of deaths.

The 2011 Fukushima accident was much more serious. Caused by a powerful undersea earthquake and the resulting tsunami that buffeted the facility with waves nearly fifty feet high, the power plant flooded, and both grid power and the on-site backup diesel generators were knocked out, eliminating the emergency core cooling system. This eventually led to full meltdowns of three of the six reactors. Nevertheless, if anything, the Fukushima event proved the safety of nuclear power. Amid a disaster that killed some 28,000 people by drowning, collapsing buildings, fire, suffocation, exposure, disease, and many other causes, not a single person was killed by radiation. Nor was anyone outside the plant gate exposed to any significant radiological dose.

IAEA experts deaprt Unit 4 of TEPCO's Fukushima Daiichi Nuclear Power Station on 17 April 

IAEA experts depart Unit 4 of TEPCO's Fukushima Daiichi Nuclear Power Station on 17 April 2013 as part of a mission to review Japan's plans to decommission the facility. Photo Credit: Greg Webb / IAEA

From the point of view of radiation release, Chernobyl was the most serious nuclear plant disaster of all time. At Chernobyl, a runaway chain reaction led to an explosion that breached all containment. Approximately 50 people were killed during the event itself and the firefighting efforts that followed immediately thereafter. Furthermore, radioactive material comparable to that produced by an atomic bomb was released into the environment. According to a study by the International Atomic Energy Agency and World Health Organization using LNT methodology, over time, this fallout could theoretically cause up to four thousand deaths among the surrounding population. Chernobyl was really about as bad as a nuclear accident can be. Yet, even if we accept the exaggerated casualties predicted by LNT theory as being correct, in comparison to all the deaths caused every year as a result of the pollution emitted from coal-fired power plants, its impact was minor. Chernobyl -like catastrophes would have to occur every day to approach the toll on humanity currently inflicted by coal. By replacing a substantial fraction of the electricity that would otherwise have to be generated by fossil fuels, the nuclear industry has actually saved countless lives.

Still, Chernobyl-like events need to be prevented, and they can be by proper reactor engineering. In the first place, the Chernobyl reactor had no containment building. If it had, there would have been no radiological release into the environment. In the second place, had the reactor been designed to lose reactivity beyond its design temperature—as all water-moderated reactors are—the runaway reaction would have never occurred. The key is to design the reactor in such a way that as its temperature increases, its power level will go down. Water is necessary for a sustained nuclear reaction in a pressurized water reactor because it serves to slow down, or “moderate,” the fast neutrons born of fission events enough for them to interact with surrounding nuclei to continue the reaction. It is physically impossible for such a water-moderated reactor to have a runaway chain reaction because as soon as the reactor heats beyond a certain point, the water starts to boil. This reduces the water’s effectiveness as a moderator, and without moderation, fewer and fewer neutrons strike their target, causing the reactor’s power level to drop. This is why Captain Hyman Rickover chose the water pressurized reactor as the system for powering the submarine Nautilus, which, after its launch in 1954 then became the model for the Pressurized Water Reactors and related types that have comprised the vast majority of nuclear power plants ever since. The system is intrinsically stable, and there is no way to make it unstable. No matter how incompetent, crazy, or malicious the operators of a water-moderated reactor might be, they can’t make it go Chernobyl.

In contrast, the reactor that exploded at Chernobyl—a Soviet RBMK reactor—was moderated not by water, but by graphite, which does not boil. It therefore did not have the strong negative temperature reactivity feedback of a water-moderated system, and in fact, because water absorbs neutrons while graphite does not, it actually had a positive temperature coefficient of reactivity, which caused power to soar once water coolant was lost. It was thus an unstable system, vulnerable to a runaway reaction when its operators decided to do some really dumb experiments. Furthermore, with a huge amount of hot graphite freely exposed to the environment once the reactor was breached, fuel was available for a giant bonfire to send the whole accumulated stockpile of radioactive fission products right up into the sky. The Chernobyl reactor wasn’t just unstable, it was flammable!

No such crazy system could ever get permitted in the United States or any other civilized country by the local fire department, let alone the nuclear regulators. Those who died at Chernobyl weren’t victims of nuclear power. They were victims of the Soviet Union.

Can Reactors Explode Like Bombs?

In a word, no. Because water is used as both coolant and moderator in a water-moderated reactor and is replaced by cooler water when it gets too hot, it is physically impossible for such a reactor to sustain a runaway chain reaction, let alone explode like a bomb. Chernobyl was a runaway fission reaction, but it was not an atomic bomb. The strength of the explosion was enough to blow the roof off the building and break the reactor apart into burning graphite fragments, but the total explosive yield was less than that provided by a medium-sized conventional bomb.

Bombs require uranium enriched to contain over 90 percent fissile U-235, much more than the 3 to 5 percent enriched material used in commercial nuclear reactors. Highly enriched fuel is used in nuclear submarines. But even if a terrorist managed to steal the reactor out of a submarine while no one was looking, he still wouldn’t be able to make it explode like a bomb. Exquisite engineering design is required to bring a critical mass of highly enriched fissile materials together so fast that heat generated by a partial chain reaction cannot blow them apart before they can combine, all while ensuring the chain reaction occurs before the materials can separate. It took the concerted efforts of some of the world’s greatest scientists working at Los Alamos to design and implement such a controlled “implosion” system during World War II. A reactor has no such mechanism.

Nuclear Proliferation

But can’t the industrial infrastructure used to produce three percent enriched fuel for nuclear reactors also be used to make 90 percent enriched material for bombs?

Yes, it can. It is also true, however, that such facilities could be used to make bomb-grade material without supporting any nuclear reactors. In fact, until Eisenhower’s Atoms for Peace policy was set forth, the AEC opposed nuclear reactors precisely because they represented a diversion of fissionable material from bomb-making. If plutonium is desired, much better material for weapons purposes can be made in standalone atomic piles than can be made in commercial power stations. This is so because when fissile plutonium-239 bred from U-238 is left in a reactor too long, it can absorb a neutron and become Pu-240 which is not fissile, and which ruins it for bomb-making purposes. Both the United States and the Soviet Union had thousands of atomic weapons before either had a single nuclear power plant, using either highly enriched uranium or plutonium made in special military fuel production reactors that allow constant removal of fuel. Others desirous of obtaining atomic bombs could and would proceed the same way today.

As an additional safeguard against nuclear proliferation, thorium reactors can be used in lieu of uranium reactors. Thorium (atomic number 90; atomic weight 232) is about four times as plentiful as uranium but only about one-third as radioactive.

In the late 1970s, the Carter administration became interested in promoting proliferation-proof reactors and commissioned Admiral Rickover to convert the original Shippingport Atomic Power Station reactor to uranium-233/thorium. This conversion was entirely successful. However, with the halt in new reactor orders in the US following the Three Mile Island event, it has been left to India, which is uranium-short but very thorium-rich, to move forward with the technology.

Nuclear power is safe. Close to a thousand pressurized water reactors have been operated on land and sea for the past seven decades without causing harm to a single member of the public. No other major power source has a safety record that is even remotely comparable. Moreover, it is clean and unlimited. Yet because of a scare campaign mounted by opponents motivated by ignorance, ideology, or interests, we have been denied the immense benefits that it offers.

How can this situation be rectified? In the next part of this series, I will lay out what needs to be done.

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Robert Zubrin is an aerospace engineer and the author of eleven books on space exploration, with a particular focus on Mars. He holds a Ph.D. in nuclear engineering from the University of Washington.