Energy Policy and Environmental Choices: Rethinking Nuclear Power

Will the public rethink nuclear power?

I have not posted anything to this blog about pebble bed reactors for months. I have been busy developing a way to educate the general public about the broader issues of nuclear power.

Most people to whom I have presented the pebble bed reactor have been encouraging and supportive. The most common query I receive is "what about the waste?".

I now think public acceptance of nuclear power will depend on reprocessing to burn up the most hazardous radioactive waste. Also, reprocessing will wondrously provide a century of power just from the existing spent fuel inventories at nuclear power plant sites. Not only can non-fissile U-238 be bred into plutonium fuel, but abundant thorium can also be bred into U-233 fuel. We can have fuel that meets all our energy needs for thousands of years and waste that decays in a few hundred.

I have tried to rethink the advantages and disadvantages of pebble bed reactor technology. which I summarize below.

ADVANTAGES

• Passive safety makes core meltdown impossible.
• Modularity allows smaller plants, with less capital investment risk, and distributed siting.
• Small size permits factory mass production and on-site assembly.
• High temperature, air cooled reactor needs no water for cooling.
• 50% efficiency means 2/3 the fuel use.
• High temperature permits direct hydrogen production.
• Multi-layer pebbles containing all reaction waste products are ready for burial.

DISADVANTAGES

• Technology learning curve not yet fully traversed.
• Licensing in the US will require new NRC skills and knowledge.
• US needs more nuclear power now, from already approved designs.
• Fuel supply will be strained at the proposed one-unit-per-week installation schedule.
• Reprocessing fuel in the hard pebbles will be difficult.

DARTMOUTH COLLEGE ILEAD
ENERGY POLICY AND ENVIRONMENTAL CHOICES:
RETHINKING NUCLEAR POWER

This is an 8-week course developed for the Dartmouth Ilead continuing education department. The course meets 2 hours a week beginning March 31, 2008, at Dartmouth College in Hanover NH. More information is available at http://rethinkingnuclearpower.googlepages.com.

The PowerPoint slides and audio of the talks will be posted after each session.

Syllabus

Global warming continues. The world consumes oil and gas faster than finding it. We import oil from unstable countries. Producing ethanol from corn consumes almost as much energy as the ethanol delivers. Sites for wind and hydro power are limited. Can more nuclear power help? Are the health risks acceptable? One theme will be how many? How many acres of corn? How many power plants? How many windmills? How many tons of uranium? How many tons of CO2?

1. Introduction

Energy units, uses, sources
Social benefits, demand growth, conservation, developing world
Periodic table, nuclear fission, nuclear power plants

2. Fear

Chernobyl, Three Mile Island
Radiation, health, safety, waste
Nuclear weapons proliferation

3. Environmental choices

Oil and gas depletion
Global warming, mining, coal, oil shale, tar sands
Wind, hydro, solar
Corn, sugarcane, cellulosic ethanol, biodiesel
Uranium and thorium availability

4. Current technology

Submarines and ships
Operating nuclear power plants, industry structure, NRC
Current products: GE, Westinghouse, Toshiba, Areva

5. Nuclear power plant visit

Vernon

6. New technologies

High temperature gas reactors, liquid metal reactors
Hydrogen production, hydrocarbon synthesis, coal-to-liquid, electric cars

7. Global Nuclear Energy Partnership

Integral fast reactor, waste reprocessing
Fuel supply for non-nuclear nations
Current public awareness, funding, activities

8. Debate

Antinuclear activism, Union of Concerned Scientists, Caldecott
Public opinion, NEI, environmentalist shifts
Congressional and presidential candidate's views

Idaho National Laboratory would build the first US PBR

INL Very High Temperature Reactor

In the hospital waiting room last week I was astonished to find the January 2, 1989, copy of Time magazine. Time described an "inherently safe...heat-resistant ceramic spheres...cooled by inert helium gas" reactor to be built by the US government in Idaho Falls. This pebble bed reactor project has been awaiting funding for at least 18 years.


The 1989 Time magazine also contained an article, Global Warming Feeling the Heat, quoting remarks by James Hansen, head of NASA's Goddard Institute for Space Studies, the first high level US scientist to emphasize the effect of society's CO2 emissions on climate.




It's taking us more than 18 years to face up to the facts that

• our CO2 emissions contribute to global warming, and
• nuclear power can reduce CO2 emissions.

Idaho National Laboratory

Idaho National Laboratory (INL) is situated on 890 square miles of the southeastern Idaho desert. Established in 1949, it has been the principal locus of research and testing of nuclear power systems in the US. The first nuclear reactor to produce electric power operated there in 1951. INL has designed and constructed 52 nuclear reactors, including breeder reactors, marine propulsion reactors, boiling water reactors, and a gas cooled reactor. INL employs approximately 8,000 scientists, engineers, technicians, and management personnel.

INL currently operates two nuclear reactors, including the Advanced Test Reactor, used to test materials for building future reactors. Materials can swell or become brittle after long periods of radiation. This reactor operates at such a high neutron flux that the effect of years of exposure in commercial reactors can be duplicated in weeks or months.


Pebble Bed Reactor Fuel

Together with Oak Ridge National Laboratory and BWXT, INL has been fabricating ceramic-encapsulated uranium fuel for the pebble bed reactor in 2006. Sample fuel cylindrical pellets were placed in the Advanced Test Reactor to test the materials in the high neutron flux. These fuel pellets will be removed and examined in 2008, having been exposed to the equivalent of many years of exposure within a pebble bed reactor. INL plans to test the complete fuel spheres as well.

US Energy Policy Act of 2005

The US Energy Policy Act of 2005 directs the establishment of a Next Generation Nuclear Plant to produce electricity, hydrogen, or both. INL is specified as the site of the nuclear reactor and associated plant. The Act authorizes $1.25 billion for the project, however the Congress has not yet appropriated this money.

Currently there are six candidate technologies under study at INL.

• Gas Cooled Fast Reactor (GRF)
• Very High Temperature Reactor (VHTR)
• Supercritical Water Cooled Reactor (SCWR)
• Sodium Cooled Fast Reactor (SFR)
• Lead Cooled Fast Reactor (LCR)
• MSR Molten Salt Reactor (MSR)
  

Nuclear Hydrogen Production

Hydrogen is a feedstock for the production of hydrocarbon vehicle fuels, such as H3COH (methanol) and H3COCH3 (dimethyl ether). Efficient production of hydrogen is possible with the high 900-950 C temperature of a very high temperature gas reactor, such as the pebble bed reactor. Two candidate hydrogen production technologies are the sulfur-iodine cycle and high-temperature electrolysis under study at INL.

The PBR is a prime candidate for the Generation IV prototype to be built at Idaho National Laboratories.

PBRs can halve global warming CO2

In February, 2007, the Intergovernmental Panel on Climate Change published the report Climate Change 2007 which gave further evidence that (a) the climate is warming, and (b) human activities are part of the cause. Most of the press coverage focuses on the warming, the shrinking glaciers, starving polar bears, and rising oceans. The evidence that man-made greenhouse gasses actually cause the global warming is harder to communicate. The report quantitatively models the contributions of various human-caused components, such as CO2, N2O, and CH4, of which CO2 is the largest.

To my mind, the clearest evidence is the above chart, published by NASA. Over the last 170,000 years atmospheric CO2 levels and global average temperatures have changed in tandem. The two graphs are too similar to be attributed to chance. The frightening aspect, at the top right, is the sudden increase in CO2 levels of the last decades. This portends a similar increase in temperatures. Pebble bed reactors can decrease future CO2 emissions. Here's how.


Quads of fossil fuels burned annually in the US


One quad is one quadrillion [10^15] BTU per year. The first post in this blog has a DOE energy flow chart indicating consumption of 55 quads of US fossil fuel plus 29 quads of imported petroleum. These 84 quads are burned, producing CO2. US coal, primarily for electric power, accounts for 23 quads of this. We can begin to cut CO2 emissions by replacing coal electric power with nuclear electric power.

The previous post showed how pebble bed reactors can be built in factories, much as Boeing builds airliners. Boeing builds at least one airliner per day. Let's suppose we build just one PBR module each week to replace coal-burning electric power. The thermal efficiency of a coal power plant is about 33%, so it takes 3 times as much energy in as it sends out. Here's how many quads of fossil fuel one 100 megawatt PBR module can save.

100 x 10^6 watt [1 megawatt = 106 watts]
x 3.4 BTU / watt hour
x 24 hours / day
x 365 days / year
x 3 [to account for 33% efficiency]
x 1 quad / 10^15 BTU / year
= 0.0089 quad

So building one PBR module per week displaces 0.0089 x 52 = 0.46 quads of fossil fuel energy every year thereafter. The bar chart above illustrates the concept. The displaced quads can be from coal, crude oil, or natural gas.

Deploying pebble bed reactors can reduce the US-produced CO2 that contributes to global warming, by half, in this century.

We can solve the US energy crisis

MIT pebble bed reactor drawing

The United States has an energy crisis, incorporating energy costs, global warming, and national security. A pebble bed reactor is a nuclear power plant that can generate electricity and hydrogen, eliminate carbon emissions, and cut US dependency on unstable oil producing nations.

We'll introduce the pebble bed reactor in more detail later. Now let's recap some facts about US energy.

Energy costs are high and rising, perhaps +40% in 2005. The price of gasoline surged through $2.00 per gallon, through $3.00, fell back to $2.00, and now hovers near $2.50. Much of the public agitation associated with $3 gasoline has waned, but the crisis is real as ever.

US carbon dioxide emissions continue to rise at 2% per year. The US did not sign the Kyoto accord to reduce them because we don't have the energy structure and policy in place to do this. Meanwhile we contribute to global warming.


80% of US energy comes from fossils

Eighty percent of all US energy comes from fossil sources that include coal, petroleum, and natural gas. We do derive 11% of our energy from the 100 nuclear power plants that were constructed decades ago; none have been started since the 1970s. Only 1% comes from solar, wind, and geothermal energy.


32% of US energy is imported

We import just about as much energy as we expend in the transportation sector. The figures above are in quads, quadrillions of BTUs. Above is the 2005 energy flow diagram from the US Department of Energy. It's worth while to browse the extensive statistics available at the DOE Energy Information Administration.

Of course billions of dollars flow to the oil producing nations such as Saudi Arabia, Iraq, Iran, and Nigeria. Much of this money in turn flows to fanatics and terrorists. Reducing our energy imports will improve national security.

Imported energy also increases the trade deficit. On a micro scale, think of a car driving 60 miles per hour at 20 miles per gallon. That's 3 gallons an hour, or $9.00 per hour. Nearly two thirds of that money, $6.00 per 60 minutes, flows back to the energy suppliers. So just envision each automobile tailpipe pumping 10 cents per minute into the coffers of Saudi Arabia, Iran, Venezuela, etc.