It is a foregone conclusion that nuclear power will be part of the equation that reduces our carbon emissions in the future. That said, there are plenty of issues that progressive environmentalists need to address with respect to the effort, as we need to be sure that this conversion, which will take place over a number of years, gets handled in the best manner possible.
As policies lean toward increasing our dependence on nuclear, we need to address that conversion's environmental impact. Access to water will become more scarce. Thermal pollution in the water systems must be checked. We need to be sure that plant efficiency gets addressed in a serious way, and discussions about processing and storing nuclear waste have to be at the forefront. And while accidents happen, we need to stick to the real safety issues and leave the straw men at home.
If we are going to influence the people who sit at round table talks about nuclear power in the United States, we need a list of bullet points. The following is just a start.
Nuclear energy is not a renewable technology, and the infrastructure to support it has a significant environmental impact apart from the obvious radiation safety and waste disposal. The reason it is on the table is that it can produce energy on a large scale with very little greenhouse gas emmission.
According to the DoE, Alabama, Arizona, Arkansas, California, Connecticut, Florida, Georgia, Illinois, Iowa, Kansas, Louisiana, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Nebraska, New Hampshire, New Jersey, New York, North Carolina, Ohio, Pennsylvania, South Carolina, Tennessee, Texas, Vermont, Virginia, Washington, and Wisconsin are nuclear states.
By elimination, Alaska, Colorado, Delaware, Hawaii, Idaho, Indiana, Kentuky, Maine, Montana, Nevada, New Mexico, North Dakota, Oklahoma, Oregon, Rhode Island, South Dakota, Utah, West Virginia, and Wyoming are not.
It is safe to assume that the decisions we make today will impact the world for hundreds of years to come. What follows here is a short list of issues for the round table discussions. It is by no means complete -- a good discussion of topics will require a number of heads and series of diaries.
To start, let us consider:
Water Use and Thermal Pollution
Large scale power sources generate heat, and components must be cooled for operation. For a nuclear plant, the need for cooling is substantial and dire. Nuclear plants require more water than coal burning plants, so a proposition of replacing coal burning plants one for one has a significant impact on the local water supply. Water must be available to farmers and residents in the event of a shortage -- the politics of water distribution is increasingly crucial.
Power plants often cool components by heat exchanging a closed water systems with a nearby river. They aren't producing any chemical pollution, but they are heating the natural water system to unnatural temperatures. Often good planning can minimize the impact this has on a local ecosystem. Man made cooling ponds can sometimes be created in exchange for preserving other lands that the ponds destroy. In any case, though, we must carefully consider the real impact that a new plant construction will have on an eco system.
As progressives, let's make sure that our policy makers do not overlook the entire impact of building new infrastructure. Using nuclear power as a stop gap should not mean building new power plants to the exclusion of energy conservation and renewables.
Plant Efficiency
Nuclear power plants operate at roughly 30% efficiency. The main reason? They use water to turn the turbines. Water's boiling temperature is low, so the temperature difference between the hot and cold sinks is small. If that temperature difference increses, the power extracted from the plant increases.
In recent years, there has been innovation to increase plant efficiency -- let me direct you to the MITnews article that discusses some of that research circa 2006. There is always room for innovation.
As progressives, let's work to quash the meme, "We already have the technology for nuclear power." Basic science and technology research can always make it more efficient.
Nuclear Waste Storage
Dealing with nuclear waste is always going to be ugly. One danger that progressives can work to avoid is one of ecojustice. Nobody wants this stuff in their backyard, so the people with fewest resources to organize and object are the more likely to live near a radioactive waste repository than those who have influence. We have to be vigilant about fairness.
With all due respect to Secretary Chu, this quote should give us pause:
I am very confident the Department of Energy with cooperation with other countries can get a solution to the nuclear waste problem.
--Steven Chu
Perhaps we should bookmark PDNC's 350 Climate Action diary for future use. Morality and justice are key.
In choosing a site for a waste dump, the people at round tables consider the time scales at hand. One rule of thumb is 100/1000/10,000. The radioactive waste is highly dangerous for 100 years, it will be reasonably safe from a radioactive standpoint after 1000 years, and the goal is to store the waste for a minimum of 10,000 years. The reason that the folks at a roundtable chose Yucca Mountain, for example, is because it is expected to be stable on a geologic scale, which is a lot longer than 10,000 years. So much for how a committee chose to put a dump site in a volcanic mountain.
Another storage safety benchmark is 1,000,000 years. That is geologic time.
Here are some very rough, order of magnitude time scales about nuclear waste:
Five minutes -- A fuel rod taken from reactor core will kill you stone dead if you are near it. Robots die quicker than people.
Ten hours -- Not safe for people, but can be handled by robot.
Months -- Can be moved by robot from a cool-down area to temporary storage in a pool within the reactor site.
Tens of years -- Process for permanent storage.
As progressives, let's remain vigilant about fair and safe long term waste storage.
Accidents Happen: Chernobyl and Three Mile Island.
Chernobyl was in a test mode during the meltdown -- the problem was that the crew screwed up the test and the emergency shutdown system was designed in a particularly horrible way. Also, as I will repeat, the Chernobyl reactor was not designed to fail safe. The design depended on having a competent crew to maintain operations.
This is my recollection of the story.
They were testing the auxiliary power response for the pump that drove water flow through the core. It was essential that water flowed through the core of this particular (bad) reactor design: without the water flow, the reactor wonn't maintain temperature and will quickly melt down.
The test procedure was to turn off the primary pumps and check that the backup power source deployed. It turned out that the backup source deployed, but failed to drive the pump adequately -- which was a known failure mode for this particular reactor.
What followed was an unfortunate combination of colossal incompetence and frightfully poor engineering.
The fission rate in this reactor was moderated by a Xe isotope. The reaction rate was low when the crew wanted to do the test, because Xe population happened to be high. The crew didn't seem to understand that they should have waited for the Xe to decay before starting the test. Rather than wait for the fission rate to pick up on its own, they chose to remove the control rods from the core.
The feedback inherent to the system was positive -- when they pulled out the control rods, the core heated up and the water in the reactor started boiling. Neutrons passed through the bubbles more efficiently than they did through the liquid water, and the fission rate increased. The crew thought this was a good thing, and that they'd accomplished their mission by removing the rods.
They started the test, and shutdown the primary power to the pump. The backup source didn't adequately cool the core, so the temperature started to rise. After about twenty minutes, the crew tried to shut down the reactor using the emergency shutdown button.
When the shutdown occured, there were no control rods inside the reactor, there was inadequate coolant flow, the power output is about 150% normal, and the core temperature was well over the redline level. This emergency system was set to insert an independent set of control rods to shut down the reactor -- but it removed some of cooling water to make space for the rods before inserting them.
In the ~15 seconds between the time the water was removed and the control rods were inserted, the core underwent exponential growth of the fission rate -- a spontaneous self-generating reaction. This is really no different than what happens inside a nuclear bomb, and it has the mother of all postive feedback.
The fuel rods disintegrated, and the broken pieces blocked the graphite control rods from entering the assembly. Temperature rose without bound inside the reactor, and it took about two minutes before the containment lid blew clean off. The explosion scattered pieces of control rod and spent fuel all over the Chernobyl complex -- all junk that was intensely radioactive. Superheated graphite chunks from the control rods were flaming and strewn everywhere.
The control room crew chief went outside to see what had happened, saw the burning graphite, and didn't realize that there was a meltdown taking place. He called the fire department. The crew didn't realize that their radiation meters were pegged, and that the dose was offscale. And their large scale radation detector was broken and unchecked.
The firefighters did not know they were fighting a reactor fire, and they had no clue that they were being exposed to radiation. They called down by radio and described a feeling that pins and needles were pricking at their faces, though. They managed to put out the fire, but none of them ever came down from the roof.
At dawn people saw the hole in the ground, and finally realized what happened.
The reason that bringing up the Chernobyl disaster is a straw man -- the Chernobyl reactor design failed in many ways that are not relevant to the US designs. This particular accident was riddled with design flaws that do not exists in US reactors. At minimum, they are designed to fail safe, and the design flaw in the emergency shutdown system was peculiar to Soviet power plants. An expert in nuclear power will not take the Chernobyl argument seriously.
That said, Three Mile Island is a much better example for this argument. The rods melted at Three Mile, but the containment vessel was never breached. And they could turn off the machine in a failsafe way. My understanding is that the Three Mile accident was due to a series of faulty sensors that were misunderstood by an inexperienced crew.
As progressives, we need to know that there is adequate safety checking and crew training -- and that we are continually engineering the best failsafe systems possible. Both Chernobyl and Three Mile Island could have been easily avoided.