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Would You Trust an 80-Year-Old Nuclear Reactor?
the_newsbeagle writes "The worst nuclear near-disaster that you've never heard of came to light in 2002, when inspectors at Ohio's Davis-Besse nuclear power station discovered that a slow leak had been corroding a spot on the reactor vessel's lid for years (PDF). When they found the cavity, only 1 cm of metal was left to protect the nuclear core. That kind of slow and steady degradation is a major concern as the US's 104 reactors get older and grayer, says nuclear researcher Leonard Bond. U.S. reactors were originally licensed for 40 years of operation, but the majority have already received extensions to keep them going until the age of 60. Industry researchers like Bond are now determining whether it would be safe and economically feasible to keep them active until the age of 80. Bond describes the monitoring techniques that could be used to watch over aging reactors, and argues that despite the risks, the U.S. needs these aging atomic behemoths."
Meanwhile, some very, very rich individuals have taken an interest in the future of nuclear power.
If I learned anything from SimCity it was to never let your reactor stay online beyond its intended life - unless you have disasters turned off, of course.
1) Just to be clear: There are NO 80 year old reactors. If Chicago-Pile 1 was still operating, it would turn 70 this year. The oldest currently operating nuclear reactor is the Oyster Creek facility. This reactor came online December 23rd 1969 making it 42 years old curerntly. This is according to Wikipedia. http://en.wikipedia.org/wiki/Oyster_Creek_Nuclear_Generating_Station
2) All NRC regulated reactors have maintenance performed on the systems every outage, to the point that much of the facility is newer than the day it turned on. This is due to maintenance and repair activity, as well as upgrades to improve efficiency. The article calls this "midlife refurbishment". The industry does this because it is easier and less costly than a new reactor. The thought process of the industry is that it is easier to tear down and rebuild under the existing license than it is to get approval for a new license. If the industry could feasibly replace a reactor vessel, I would bet they would.
3) ASME Boiler and Pressure Vessel Code Section 3 is a good code. Creep, Fatigue, Corrosion, and many other issues are addressed in this code that the non-nuclear codes for B&PV only tough upon exotic need, and then refer the engineer to the section 3 code. I encourage you to read it.
4) Some reactor operators send material samples to the Advanced Test Reactor at the INL for accelerated radiation age testing. This information is sought by the reactor operators to gain a better understanding for themselves about their own equipment.
5) Reactors are designed for a much longer life than 40 years, but the NRC set the 40 year license to force a mid-life review. Reactors get far better treatment than any car or plane that most people have ever have ridden in. In this context, a 40 year old reactor properly maintained is very possibly not a safety concern.
6) The Davis-Besse RPV head mentioned by the article was a case of criminal conduct in the eyes of some people, and is not considered normal operating behavior by people I have met from the industry. Whatever the facts are, the indictment can be found here. http://www.corporatecrimereporter.com/documents/indictment.pdf
7) Reactors designed to operated under the NRC have a "defense in depth" safety approach. The reactor and facilities are given a design basis accident that is a conservative forecasting of potential accident scenarios.
8) The NRC has a glossary available to you http://www.nrc.gov/reading-rm/basic-ref/glossary.html note the term "meltdown" is not there. Many people associated with the nuclear field feel that it is a poor term that does not adequately describe a problem's behavior or severity. This is borne out of the use of the term for several reactor failures that all had different designs, behaviors, and severity of failure.
9) New reactor designs offer some stimulating improvements. The Generation 4 reactor effort can be found at http://www.gen-4.org/ currently the US is operating Gen 2 reactors.
Once upon a time, back when nuclear power plants were first being built, it wasn't especially clear what effect neutron embrittlement would have over the lifetime of a nuke plant.
As a result, the plants tended to be over-engineered to astonishing degree.
Newer plants weren't over-engineered to such an extreme degree, but were still over-engineered.
In other words, the 40 year design lifetime was a VERY conservative estimate. Whether they can survive 80 years is debatable, but that's a question for the engineers/scientists.
"I do not agree with what you say, but I will defend to the death your right to say it"