Wednesday, June 29, 2011

The Nuclear Safety Paradox: Guest Post by Jeff Schmidt

This is a guest post by Jeff Schmidt on an important subject: The Nuclear Safety Paradox. Schmidt's previous guest post was Flawed Analogies, describing common but misleading ways of describing nuclear plants.

Over the past several months, a thought has been at the back of my mind about nuclear safety. I feel is important to enter this issue into the ongoing discussion about Nuclear Power in our country.

There are many people who are opposed to new nuclear. They look at the events that have unfolded over in Japan, and worry that the same can happen here, unless we quickly move away from nuclear power. To that end, they actively seek to slow or block the certification of new designs, and the construction of new power plants.

Rod Adams of the Atomic Insights Blog has recently posted an example: "Friends of the Earth" seeking to stall certification of the AP1000 design . The AP1000, for folks who are not familiar with it, is a new design by Westinghouse Electric (a subsidiary of Toshiba), which adds an emergency passive cooling system to the Light Water Reactor. This cooling would operate in the case of a complete loss of electric power for active cooling, as was the case in Fukushima.

A passive cooling system uses basic physics to work. Passive cooling systems do not require any outside intervention, like electric power, fuel, or other inputs. They work automatically, and always work because those principles of physics never change. Examples of passive cooling techniques include convection in the cooling fluid, air cooling, gravity-fed water cooling, etc). Such passive cooling will keep cooling the reactor from melting down for an extended period of time, when no outside power is available for pumping cooling water.

This is, objectively, a good safety improvement over previous designs, such as those at Fukushima Daiichi Nuclear Power Plant, or any of the reactors currently in use in the U.S. (I would add that GE-Hitachi Nuclear also has a new design for the BWR which adds passive emergency cooling, which they are trying to put into the market, and I believe other companies and researchers have other ideas for passive cooling systems in new designs).

So, why don't we have any of these new, safer designs in the U.S.? Largely because we can't get any new designs certified or built.

The Paradox

I have come to believe that in the U.S., we have a Nuclear Safety Paradox - namely, that because of our concern for safety, we are keeping older, less safe designs in active service longer, because new designs have not, and are not, being certified and built. I realize that many of the people who are opposed to nuclear, and are attempting to block forward progress, truly feel that no nuke is good, no nuke can be safe.

In contrast, I believe that most Americans, like myself, do have faith that engineers can create safer designs, in time. I also believe that, while there is probably some good opportunities to put solar and wind power to use in our country, we are not at the necessary technology level to try to deploy Wind and Solar on the scale necessary to completely replace nuclear. We may get there some day, or we may not, but we need much bigger advances in technology to get to a total renewable solution, compared to building safer nuclear reactors.

Now, I don't think the older designs present a large safety threat - after all, there has only been one meltdown in U.S. reactor history, Three Mile Island, and that was, in the end, from a safety perspective, a non-event. But there is still a risk that certain circumstances, very rare, but not impossible, can come in and cause loss of cooling to the old reactors, and that in some circumstances, they might not handle the loss of cooling as gracefully as a reactor which has a passive cooling system. None of us want to face the prospect of having to evacuate a 10 or 20 mile zone around a nuclear plant for 6 months, or a year, or potentially longer. None of us want to see a situation where one natural disaster is followed by a nuclear incident that makes cleanup and repair of the damage from the natural disaster be delayed for long periods.

In particular, I don't think Vermont Yankee presents a big threat to Vermont, as I think Meredith has made many good arguments over the past several years about the safety of even the "old" generation of nuclear plants. Nuclear plants here in the U.S., including Vermont Yankee, have added some additional safety features to, e.g. prevent building up hydrogen gas and resulting hydrogen explosions - safety features apparently lacking at the FD reactors in Japan. We have already made upgrades, well BEFORE the Fukushima reactor meltdowns and explosions, to address some of the exact scenarios that the Japanese ran into. That tells me that to a large extent, our engineering and regulatory systems are very actively working to prevent such a disaster.

The Missing Conversation

However, I suspect that we'd be having a much different conversation if there were plans to be building new nuclear power plants around the country, and in Vermont. Nuclear Power currently provides about 20% of the electricity generation in the United States. To take that offline, we need something to replace it. We could build natural gas (and, in fact, that is happening), but natural gas is not without its problems, either - environmental damage, deaths from gas explosions , and supply which, while ample in the short term, does not promise long term security.The Natural Gas marketers themselves only claim a 100 year supply , and that is including speculative, undiscovered resources. Also, that 100 years is only if we don't increase exports and domestic consumption. We can't expect "cheap" natural gas to last forever. Wind and Solar may someday be able to supplant nuclear power, but there are enormous technical and financial challenges, larger than even for Nuclear, in trying to do a truly massive build-out of Wind and Solar.

I've heard some people compare Fukushima Daiichi (and before that, Chernobyl) to the Titanic. They like to say that "The Titanic was a New, Safer Design - until it sank on it's maiden voyage." But we didn't stop designing or building ships because of the Titanic, and I think everyone would agree that large commercial ships have gotten much, much safer - both as a result of improved design, as well as improved operational practice, over the years. I truly believe that with iteration (that is, the design and construction of new generations of technology after learning lessons with previous generations), all technology gets better with time.

This is almost surely to be true of Solar and Wind as well, but today nuclear reactor technology is better positioned to provide that power than Solar and Wind. As well, I'd rather see the market pick winners and losers than a system that hamstrings one solution (nuclear), while pushing forward another solution, based upon an inflated sense of risk and fear.

I've had the privilege of growing up in a period of extreme technological advancement in nearly every field of engineering, but perhaps none is more illustrative of the power of iterative improvement as computers and electronics. Since the 1970s, we've probably had close to 40 generations of computer technology (about one generation per year). Computers have gotten staggeringly faster, with more storage space, better reliability, more RAM, amazing graphics, very high speed networked communications, high quality sound, much smaller physically, and all at orders of magnitude lower cost. This is the result of lots of iterative improvement.

Where are the Iterations? Where are the New Nuclear Plants?

If there had been built, in the last 10 or 20 years, a gigawatt or two of new, safer nuclear power plants in Vermont, I bet Meredith, nor anyone else, would be trying to keep Vermont Yankee running, because there would be something better in place already, and it would just be time to retire that particular plant. The most natural way to get rid of old nuclear power plants is to build new, improved nuclear power plants to replace them. Without replacement, the result is (and we are seeing this all over the country) that we keep older plants online longer (however, those older plants are upgraded and updated with new safety features, new pipes, new turbines, etc, to keep them as safe as possible).

The most natural way to make nuclear safer is to increase the rate of iteration of generations of the technology. Of course, we need to go at a slow enough pace that we aren't risking disasters, but I think we can do better than 30 years per generation. I think the key is what standard we hold the NRC to: we can enable iterative improvement not by giving it a mandate to ensure 'perfect' safety, because they really can't ensure perfect safety, but rather, our standard should be, "Are the new designs being considered at least AS SAFE OR SAFER than any current designs".

That is how you achieve progress in any field of engineering - not, "Is it perfect, right now", but "Is it better than what we already have". Perfection is a goal we are always chasing, never achieving. This is why computers can keep getting better and better and better, and why nuclear reactors could keep getting better, and better, and better.

Ending the Paradox

Let's end the nuclear safety paradox by getting new, safer reactors built to replace the older reactors, and by giving the NRC the resources, people, and mandate to improve and speed up the certification process. We should enable a fairly rapid iteration of improved generations of nuclear reactor technology. As with other technologies, new improved generations will fairly quickly replace the old generations, leading to ever safer nuclear reactor designs.

AP 1000 illustration courtesy of Westinghouse through Wikipedia
Vermont Yankee photo also Wikipedia.

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