Of Pandora and Prometheus

The myths of Pandora and Prometheus are some of the most interesting of the Greek myths.

What I didn’t realize until recently is that these two myths are related.

Prometheus—whose name means “forethought” or “forward thinker”—was a Titan who helped to create humans and stole fire from Zeus and the rest of his Olympus gang to help humans live a better life.

For his troubles, Zeus eventually chains him to a rock and has an eagle eat his liver each day. The liver grows back each night so that the punishment can be eternal.

Many know this myth and many nuclear projects use the word “Prometheus” in honor of his actions.

Certainly, given nuclear energy’s potential it feels a great deal like we’ve stolen the ultimate fire from the universe.

Pandora, though, I was less familiar with.

Like most folks, I knew that Pandora’s box was filled with evil things and that she loosed them on the world by unlocking a box she’d been told to keep shut.

We’ve all heard the phrase “opened

Pandora’s box” to connote something that someone had done that created all kinds of problems.

Anti-nuclear activists like to describe nuclear technology as an act of opening a Pandora’s box.

They almost gleefully describe a litany of ills and problems that the curious scientists that developed this technology have opened with their discovery.

When the documentary “Pandora’s Promise” was released this past summer, and director Robert Stone explained that Pandora’s myth ends with the revelation that hope for all mankind was at the bottom of the box, I decided to investigate a bit further the story of Pandora.

Who was this Pandora woman anyway?

Pandora—the name means “all gifts”—is the first human woman in Greek mythology. Before her, all females were either gods or Titans.

Zeus demanded that the other Olympian gods create her in order to play a trick on mankind as punishment. What transgression was Zeus so angry about? He was angry because Prometheus stole fire and gave it to mankind.

Depending on the version of the myth, the gods first tried to give her to Prometheus, who recognized the potential trick and refused her.

The gods then give her to Epimetheus, Prometheus’s brother. Epimetheus means “after thought” or “hindsight.” He’s less well known than Prometheus, mostly because he always failed to plan ahead.

These myths are compelling. Nuclear technology is indeed the fire we stole from the gods.

As mere mortals, it has taken thousands of competent and dedicated engineers and scientists to wrest this fire from Olympus and bring it to mankind.

Some days, it certainly feels like our livers are being pecked out by something—and that, like Prometheus, we are being punished.

However, the campaigns by anti-nuclear activists over the past several decades now appears to be Epimetheus-like.

Lacking any foresight, they’ve been seduced by a pretty vision of the future. The ills our continued reliance on fossil fuels has created certainly seems to be Pandora’s box.

Our air is dirtier, our energy more expensive and less reliable, and our future less certain because of the delays in getting nuclear energy used more widely, not just in the U.S, but globally.

But there is still hope at the bottom of that box.

Many environmentalists have rejected the traditional anti-nuclear stance. There has been quiet talk in the corners of the movement that perhaps that knee jerk stance was wrong.

The documentary “Pandora’s Promise” brings that discussion into the forefront and perhaps begins to get us to the bottom of that box and to the hope that it brings.

This article was originally published in Fuel Cycle Week #543, 10.31.2013. where Margaret is a regular columnist. To become a subscriber, go to fuelcycleweek.com or contact the publication at info@fuelcycleweek.com.

Spent Nuclear Fuel

This is a reprint of an article written for SAM group. The first article was an overview of nuclear power.

The last time I wrote here, I filled up my space with an explanation of the basics of nuclear power technology. I left with a cliffhanger on what to do with spent fuel.  I was not ignoring or lightly treating the question. It deserves a column all its own for more complete discussion. Trying to tack it on to the end of that column would have been a disservice to all.

Before we can discuss options for spent fuel, we must have a common basis of understanding. So back to the reactor for a moment. All fission reactors work essentially the same way, they split a larger atom (usually Uranium) into two smaller atoms and two or three extra neutrons. The amount of uranium loaded into a core at the start of a typical two year cycle is about 50 metric tons. Of that, less than 2.5 metric tons is U-235 (the isotope that splits most easily), the rest is U-238. Typically, this fuel would stay in reactor six years or so and generate over 21,000,000 MWhr of electricity. When the fuel is removed, there is still about 48 metric tons of uranium, but only about 0.5 metric tons of U-234. However, there is now about 0.5 metric tons of plutonium that was generated when the U-238 picked up a neutron and lost an electron. So of the initial 50 metric tons of uranium, at the end of six years of operation we still have about 48.5 metric tons of material that could still be used in a reactor (uranium and plutonium). Only 1.5 metric tons are the fission remnants (called actinides).

To put this on an annual basis, each year, each reactor in the US generates, on average, 24.25 metric tons of reusable material and 0.75 metric tons of actinides. For a total spent fuel mass of about 25 metric tons. With 104 operating reactors, that means about 2600 metric tons of material is generated, with about 2522 metric tons of reusable material and about 78 metric tons of true waste material. If all 2600 metric tons was stored in one place, it would require about 3200 square feet of storage 10 feet deep – an area less than the end zone of a football field. If we consider only the material that cannot be reused, this space drops to an area about 96 square feet.

All of the spent material from every operating reactor in the US for their entire operating life can be contained on one football field to a depth of about 17 feet. Of this, only one end zone is needed for the waste material.

So what do we do with the stuff? I’m going to stay out of the politics of this and stick with technical options that are available today. A blue ribbon panel appointed by President Obama and Secretary of Energy Steve Chu are beginning to process of considering these options, singly or in combination, to make a recommendation.

  1. Reprocess the material and extract the usable fuel components – uranium and plutonium. This is being actively pursued in France and Japan and several other countries around the world. The US has not pursued this option for fear of proliferation risk, but could at some point in the future.
  2. Store the material in a central repository with the idea of being able to retrieve it at some point in the future if option 1) is ever exercised. This was the Yucca Mountain repository. Part of the reason it was selected as the site to consider for long term storage was that it provided the option of retrieval.
  3. Store the waste in a permanent non-retrievable depository. There is a salt mine in New Mexico that is doing just that with some government materials. However, once the material becomes encased in salt retrieval is impractical. There are a number of additional options in this category.
  4. Store the waste in situ at each reactor site until option 1) and 3) are fully up and operational. This has become the de facto solution on the ground. Most of the spent fuel is being stored in deep pools of water. These pools allow continued cooling of the material as decay of radioactive elements occurs. At most sites in the US, additional dry cask storage has been constructed to store some of the oldest fuel. These dry case storage yards are well within the plant’s security boundaries and present no additional radiation risk to the public or to the workers at the nuclear site.

Considering that many industries take the stance of dump and run with the toxic wastes that they generate, the nuclear industry has worked hard to keep all of the toxic waste materials from its industry contained and controlled. All of these options require manufacturing, construction and engineering design work. As the nuclear industry continues to move toward an expanded energy role, all kinds of industries will be needed to provide support. SAM group can help you figure out what you need to do to get started.

Nuclear Power Tutorial

I am writing a series of articles for a training organization called SAM group. I’ve been working with them to develop and offer a course in Nuclear Quality Assurance Auditor Training. We are also working together to provide consulting to businesses interested in getting into the nuclear power industry. The next few blog posts are reprints of those articles.

*************************************

It occurred to me that while much has been discussed about nuclear power in the news and in many opinion pieces, there has been an assumption that the reader is at least somewhat familiar with the technology. This has created some significant misunderstandings and some unwarranted concerns about commercial nuclear power.

Let me spend a few minutes of your time providing a groundwork about the technology and some of the buzzwords and acronyms that get thrown around by those of us who have lived and worked inside the industry for more years than we care to admit.

Nuclear power plants around the world basically generate heat. That heat is converted to steam and the steam is used to spin a turbine which drives a generator and creates electricity. The concept is the same as coal based electricity generation, just using nuclear fuel to boil water instead of burning coal.

So how is the heat generated? Very simply, when an atom is split, it converts a small about of matter into energy. The energy is in several forms, but all of them can be readily converted to heat. Because Einstein’s famous equation E=MC2 comes into play, very small amounts of matter create very large amounts of energy. This is why small pellets of uranium can create more energy that car loads of coal. It takes about 120,000 tons of coal to equal 1 ton of uranium.

There are several reactor types in operation today. Light Water Reactors (LWR’s) are the most common, by far, of operating reactors around the world today. The concept is a simple one. Regular water (called Light Water) performs two functions within the nuclear core. First, it absorbs the heat being generated and creates steam (directly or indirectly, depending on the specific design). Second, water helps to slow down the neutrons being generated. Slower neutrons do a better job of splitting uranium atoms (specifically a type of uranium called U-235).

In order to make these reactors operate, the amount of U-235 has to be increased above the naturally occurring amount in uranium (about 0.7%). Commercial LWR’s today use uranium enriched to less than 5%. This enrichment level is well below weapons grade. No commercial LWR fuel can be made into a nuclear bomb. Enriching is done via a variety of means. In all cases, one has leftover depleted uranium that contains even less U-235 than natural uranium ore.

For LWR’s the fuel is manufactured into assemblies (also called bundles) of about 100 tubes with stacks of uranium dioxide pellets. Each assembly weighs from 200-400 Kg (440-880 pounds) depending on the specific reactor design. Prior to insertion in a nuclear core, this fuel is quite benign, one can stand next to it and not receive any significant radiation dose. It requires exposure to neutrons to start a chain reaction. A single fuel bundle cannot sustain a nuclear chain reaction even after exposure in the core. Fuel assemblies are generally left in a reactor core for 4-8 years. During this time, each assembly will generate 250,000-500,000 MWh of electricity. That is the equivalent of powering about 3500 homes for that time.

Of course, the natural question. Why call them LWR’s if they use regular water? There is a second technology used today in several countries called a Heavy Water Reactor (HWR). Instead of enriching uranium, these use an enriched form of water. Hydrogen has two naturally occurring isotopes besides the common single proton you might remember from high school physics. The two isotopes add one or two neutrons to the nucleus to increase the mass. Otherwise, these reactors operate similarly.

Spent fuel is stored for at least 10 years under many feet of water. The water again serves two purposes. The first is to provide cooling to the spent fuel assemblies while the hottest isotopes decay away. The second is to provide shielding to those who work at the power plant. By keeping the assemblies underwater, virtually all of the radiation being generated is stopped by the water. After 10 years or so, most of these very high energy isotopes are gone and the fuel is easier to handle.

The rest of a discussion regarding spent fuel is another topic for another day.

Nuclear power is one of the safest and cleanest available sources of power and one of a very few options that can replace coal as our nation’s main source of base load power. The opportunities to support this industry and expand the U.S. based supply for these plants are growing as more utilities and more vendors get into the nuclear industry. SAM group can help you and your team supply parts and services to this industry with training and consulting.

Definitions and other matters

Once again, while wandering on another social media site, I ran across a question that needed answering. This time, someone wanted to know why hydrogen was never mentioned as a renewable energy source. As I wrote a response to this individual, I realized that there is significant potential for confusion and incorrect thinking around all of these terms that are thrown around today for various energy sources.

Baseload Power – Power that is generated pretty much continuously. Electrical use goes through peaks and valleys over time periods, baseload is that minimum power level that is pretty much always demanded. Most utilities will define different baseload levels for summer and winter. This seems to be a concept our FERC chairman, Mr. Wellinghoff, does not grasp. Baseload power is usually generated by the least expensive source available to the utility, but supply must be highly reliable. The three sources most commonly used for baseload power today are coal, nuclear, and hydro. Some regions use oil.

Low Carbon (Carbon free) Energy – Those sources of energy that emit little or no carbon dioxide (CO2) in the generation of energy. There is significant disagreement over how to tally the carbon impact of each energy source. Usually, it depends on the agenda of the author of any given study. Most agree that all hydrocarbon sources are NOT low carbon energy sources. All others can be considered low/no carbon sources. This includes geo-thermal, hydro, nuclear, solar, and wind. There are several more under development that may be added to this list.

Reliable Energy – Energy sources that can be relied on for consistent power generation over long periods of time. These sources are frequently considered for baseload supply. This term is not used as frequently because in the developed world, energy reliability is inherently assumed. However, as we consider new energy sources, reliability becomes important. For this article, I will assume reliable energy must be available > 75% of the time. Reliable energy sources today are coal, nuclear, hydro, oil, natural gas, wood.

Renewable Energy – These are those sources of energy that are either easily regrown, or are constantly available. Renewable forms of energy include, ethanol, solar, wind, hydro, geo-thermal, wood pellets. Renewable energy is perhaps the most misunderstood phrase in the energy pantheon. Many people believe that renewable implies ecologically sound, sustainable energy. This is not the case. Ethanol and wood pellets both are sources of atmospheric carbon, both are also not sustainable in the long term. Ethanol is currently made using corn. This places food and energy production in direct competition for land and resources.

Sustainable Energy – Those sources of energy that can be used long term with minimal total impact on the environment and without depleting the fuel source. Most consider this the intersection of renewable and low carbon sources. Typically, solar, wind, and geo-thermal are considered sustainable energy sources. Arguments for nuclear, hydrogen, and hydro are also quite compelling.

I hope that by spending a few minutes reading these definitions, I have provided some clarity to these discussions.

Solar Panels – the math

On another social media network, the question was posed…”If every single rooftop in the country was covered in PVs, I’ve heard that we would generate enough electrical energy not to need any other source of electrical power! But, has anyone done the maths?”

The questioner was from the UK. Many people immediately jumped on the issue as a dumb idea because of many other logistical issues, but no one “did the math”. Anyone that knows me at all knows that I tend to “do the math” first then look at the resulting implications.

Basis and Assumptions:

On average the sun provides about 1000 watts per square meter (at sea level, higher as you go up in elevation, but a convenient number for my purpose…)

Current solar panels are currently less than 30% efficient. We’ll use 30% because it makes the math easier. We’ll add “windage” later.

Let’s be generous – given Britain’s famous weather – and say you can generate electricity from all panels at this peak efficiency for 10 hours per day, 365 days a year.

Current consumption in UK is nearly 400TwH per year.

The Math

Solar panels (at 30% efficiency) generate 300 watts per square meter. So for each hour of sunlight, they generate 300 watt-hours or 0.3 KwH.

Over a 10 hour period, each square meter of solar panel can generate 3 KwH of electricity. Over the course of a year, each square meter could produce just over 1 MwH of electricity.

To generate 400 TwH of electricity would require almost 400 square kilometers of solarpanels.

If, on the average, one could put 2 square meters of PV’s in the most optimal south facing position on the roof of a building, then you would need 200,000,000 buildings.

Given my rather positive assertions related to both efficiency, and available sunlight, I would double that for a realistic scenario. SO, you would need to put PV’s on 400,000,000 buildings

Conclusions

Solar panels are not a panacea that will solve all of our problems. My scenario above ignores the complex grid and energy storage structures that would be required to move electricity from such a dispersed generation to concentrated population centers and industrial applications and storing summer generation for use in winter. I’m sure any utility engineer could add dozens more considerations that I’ve not mentioned.

I believe that all of the low carbon emission options must be explored and applied to the maximum extent feasible to lower both dependence on non-domestic sources of fuel and GHG impact on our planet. But, we must maintain a balanced application of all of these technologies in order to maintain a society we all want to live in.

A Parable of Power

Originally posted May 2009, given today’s news about Venezuela’s electricity woes, it seems appropriate to repost. I predict sales of diesel generators to do up exponentially across Venezuela on the heels of this news.

A farmer in western Venezuela is tired of his intermittent electric power. For several hours every day he is without electricity. Why? Primarily because Venezuela’s government controlled electrical system is inadequate to the growing population. They have large hydro electric dams in the eastern part of the country, closer to Caracas, to the major population center of the country. But that power must travel across the country on an unreliable grid to get to the farmer’s property in the mountains above San Cristobal in the west. So, for several hours each day, the farmer is without power.

This is more than just annoying for the farmer. Because he has no centralized source for water, he relies on a local well for his water with a pump. When there’s no electricity, there’s no water either. If there’s not water, he can’t water the tender plants in his subsistence garden when the rains don’t come at the right time. He also can’t get water for bathing and cooking.

So what should this farmer do?

Well, first, he built some additional tanks to store water so that during these outages, he can water his plants, cook his food, and keep himself and his family clean. But still, this lack of power holds the farmer back. Unreliable power is a key contributor to his community’s inability to grow and develop. They cannot count on electricity to light their homes, heat their water, run their computers.

So what should this farmer do?

He decided to put in something to generate electricity whenever the government provided system failed. What should he install?

A solar array? He lives in an equatorial region high in the mountains, a solar array would certainly provide significant power, but only during daylight hours and not at peak efficiency when it rains (a frequent occurrence in this region). To install a solar array means that he must also install a complex battery storage system and inverters. He is not a technical person, this is more than he can manage.

A wind turbine? The wind blows down the valley to his home pretty steadily, but again, there is an inconsistency to deal with. Perhaps it would still suffice, at least most of the time, the wind blows sufficently.

A nuclear plant? Geo-thermal facility? Both require far more resources than the farmer has at his disposal, even his little community could not band together to build such complex facility. The Venezuelan government is giving serious consideration to a nuclear plant, but the time is years away.

So what DID the farmer do?

He installed a gas-powered generator. Why? Because the Venezuelan government subsidizes gasoline to where it costs about 5 cents/gallon. A generator is easily started when it is needed and can be run only when it is needed. It is a relatively simple mechanical system that the farmer and his community can maintain without a degree in engineering. At 5 cents/ gallon, fuel is relatively inexpensive compared to his income, so the operating costs as well as the initial installation costs are low.

So what is the lesson from this parable?

Ultimately, all of the “green options” failed for this farmer. Instead, he chose a technology that provided him with the needed power, in a way he could understand and manage. We, in the developed countries, sit in our heated and air-conditioned homes, with our computers, microwaves, and refrigerators and argue the relative merits of the low-carbon options that are available to us.

How do we change this conversation?

Added 5/5/09  This is not just a parable, but a true story, not something made up by me to provoke discussion. I personally know the farmer involved in making this decision. Some facts have been altered to preserve his anonymity.