On September 26, 2010, I posted an article titled Radiation Hormesis – A Profound Truth That Might Induce a Few More Converts to Support Nuclear Energy in which I described how Lawrence Solomon of Energy Probe had been convinced by science that the low levels of radiation associated with nuclear power plant operation and uranium mining are not high enough to cause negative health effects in humans. Charles Sanders wrote the book Radiation Hormesis and the Linear-No-Threshold Assumption that included enough peer reviewed science to convince a long time skeptic about nuclear energy.
I wrote to Mr. Solomon to find out if his organization was going to change its opinion about nuclear energy and start advocating for it, rather than against it. He told me that his organization’s main issue with nuclear energy development was economic. He was not yet convinced that overturning the Linear No Threshold (LNT) dose assumption would make much difference in nuclear energy costs.
I have begun an effort to find sufficient references to convince him that the LNT is the source of a substantial portion of the costs associated with nuclear energy. Its application has increased both capital costs and operational costs. The LNT is the basis for regulations that assume that any radiation dose, no matter how low, is dangerous enough to avoid, even if avoidance costs substantial quantities of money. The term is ALARA – as low as reasonably achievable – and current regulators take a completely different view of “reasonable” than I do when it comes to cost.
I would love some assistance from knowledgeable readers in this effort to document the costs associated with the LNT.
Here is my first effort.
Larry: (You wrote: “Changes in regulation as a result of a rethink in LNT would make the economics less worse but probably not enough so to make current utility nuclear power generation technology economically viable.”)
One of the many cost increasing effects of the LNT was the decades long effort by the nuclear industry to eliminate steel alloys that contain cobalt (one trade name that you can search for is Stellite). For reasons that are beyond my materials knowledge, these alloys are particularly good at resisting wear in high temperature environments and are widely used in key areas of wear surfaces on pumps, valves and turbines in many industrial applications. Early nuclear plant designers used them in reactor coolant pumps, coolant isolation valves, and in control rod drive mechanisms. Cobalt containing alloys were widely used in the turbines of boiling water reactors.
Unfortunately, cobalt-59 has a fairly high neutron cross section and can become activated to Co-60. Co-60 is a high energy gamma emitter with a 5.27 year half life. ALARA (as low as reasonably achievable) focused researchers determined that Co-60 was responsible for about 80% of the doses received by nuclear plant workers and initiated a campaign to eliminate its use in nuclear applications.
The Electric Power Research Institute undertook a lengthy materials research program to find alloys that could perform the same functions but did not include cobalt.
http://bit.ly/a6sE3B (sorry for the use of the shortened URL, but it leads to a Google book search result that is way too long to include in an email.)
I can send you a PDF of a presentation about the cobalt reduction efforts undertaken at Brown’s Ferry Unit 1 as part of its restart. Reading through that presentation can give you a feel for the amount of attention and cost associated with this effort.(Note: You can download this presentation from TVA Browns Ferry Unit 1.)
This effort to eliminate cobalt continues to add cost to nuclear plant design and construction because the replacement materials do not work as well, so they are not widely accepted by other industrial customers who do not have any worries about neutron absorption. This makes the components for nuclear plants even more “special” and custom than they otherwise would be. As anyone who has purchased a home or an automobile will know, special materials and custom design cost money.
The effort to eliminate cobalt also removes one of the best materials for permanent magnets – samarium-cobalt – and is requiring a continuing effort to find something that works almost as well.
The effort to eliminate cobalt containing materials is driven by the belief that even the smallest radiation doses have a negative effect and must be eliminated at all cost. It is also just one of many the cost increasing effects of the regulatory insistence on using the Linear No Threshold dose response assumption.