Another Isotope has been found at minute concentrations at the Vermont Yankee leak site
Once again, the forces that are bound and determined to shut down the Vermont Yankee nuclear power plant and remove its 620 MW of reliable (90% capacity factor) electricity from the competitive supply of electricity in New England have found another hook. The incredibly detailed analysis that is being conducted of the soil next to the location where the leak from the Advanced Off-Gas (AOG) pipe tunnel was detected and fixed has revealed the presence of Cesium 137 (Cs-137) at a level of approximately 300-1200 picocuries per kilogram (0.00000000003 to 0.00000000012 curies per kilogram). In the same soil sample, the investigators have detected manganese-54, cobalt-60, zinc-65.
(See the March 31, 2010 update from the Vermont Department of Health on their page titled Investigation into Tritium Contamination at Vermont Yankee Nuclear Power Station)
Cs-137 is not a naturally occurring isotope; it is only produced when uranium is split in a fission reaction. It is not produced with every fission, breaking uranium nuclei with a neutron is a process that nearly always produces two different atomic nuclei of various sizes, but exactly which two is a matter of probabilities. There are more than one hundred different combinations where the number of protons between the two elements add up to 92 and the number of neutrons in the isotopes adds up to about 140 or 141 (if the nucleus that breaks apart is U-235). (If the original nucleus that fissions is Plutonium-239, which happens even in a uranium fueled reactor, the number of neutrons will add up to either 142 or 143.) The reason that the number of neutrons in the fission products is less than the number in the original source nucleus is that several neutrons get releases as individual particles in atomic fission.
Here is an illustration of the fission yield curve for various fissile materials.
Image Credit – Wikipedia (http://en.wikipedia.org/wiki/File:ThermalFissionYield.svg. This work is licensed under the Creative Commons Attribution 3.0 License.)
Fission products are not a “natural” part of our environment, but they are a part of our existing environment at minute quantities, mainly due to the left-overs from the atmospheric testing of nuclear weapons conducted during the 1940s-1960s. Between the US and the Former Soviet Union, hundreds of fission weapons were exploded, allowing fission products to be widely distributed among surface soils all over the world. Since Cs-137 has a 30 year half life, a bit more than 50% of whatever was released during that testing still exists and continues to decay.
It is unlikely that atmospheric testing is the source of the tiny quantities found near the leak at Vermont Yankee at a depth of 15 feet. The fission products were most likely deposited in the soil as a part of the same water that included the tritium that was the focus of months worth of discussion and speculation.
In a nuclear power plant, every effort is made to keep fission fragments inside the fuel elements through the use of corrosion resistant cladding as a first layer of containment, but cladding failures are not entirely unknown. There are a LOT of fuel rods in a nuclear fission core bundle and they occasionally fail.
According to some reports, Vermont Yankee has had a few fuel element failures in its 38 year operating history. It is possible that some of the corrosion products that form what nukes know as “crud” still contains a bit more Cs-137 than is typical for those normal bits of rust and that some of those bits ended up in the AOG piping to be carried into the soil along with the nearly, but not completely, pure H2O that leaked out into the soil.
(Remember, the new report of finding another isotope is NOT a report of a new leak from piping at the plant. It is the SAME leak that has been found and stopped. The Cs-137 is simply another component of the SAME fluid that has been found at levels several times above background but still in extremely tiny quantities – 0.00000000003 to 0.00000000012 curies per kilogram – and still in a very limited quantity of soil. That soil was found 15 feet below the surface of an industrial facility. It is not a public health risk.)
Additional reading
Breathless headline from WMUR New Hampshire – New Contamination Found At Vermont Yankee
Ruthland Herald – New radioactive isotope found at Vermont Yankee
Huffington Post – Second radioactive substance at Vermont Yankee
(The commercial media has to capture attention so they can sell ads, after all.)
Minor correction – it is 300-1,200 pCi per kilogram, not liter.
This compares to natural soil radioactivities of:
Radon – 170 pCi/kg
Uranium – 700 pCi/kg
Thorium – 1,100 pCi/kg
Radium – 1,300 pCi/kg
Potassium-40 – 11,000 pCi/kg
http://www.physics.isu.edu/radinf/natural.htm
On an unrelated note, you are probably aware of this news?
uvdiv – unit correction appreciated. I have updated the post.
I was aware of the fact that the USS New Mexico has recently been commissioned. We are commissioning about one new Virginia class sub each year. Within a few years, that rate will increase to 2 per year. The benefits of series production, even with that kind of unit volume, have worked to drive the cost per unit down to about $2 billion from an initial $3 or $4 billion for the first ones. An old friend and classmate of mine had a lot to do with that successful effort to improve the cost performance.
I see that Rod hasn’t added your blog to his blog-roll yet.
Noted and corrected. Thank you for pointing this out; apparently I never got “a round tuit” for adding The Capacity Factor.
Another typo, I think ‘…neutrons in the isotopes adds up to about 232 or 233′ should be nucleons, or spelt out as netrons + protons, or neutrons adds up to 140 or 141
Luke – thank you for the catch. I have made the correction.
Thank you Rod! Such terrific support for Vermont Yankee. You did the numbers, explained the fission issues, and just generally wrote a great post. I plan to steal some of the numbers and ideas for one of my posts. The only problem: I don’t know quite how to enhance or improve what you did! Thank you again.
We had a Helen Caldicott visit yesterday at neaby at Dartmouth. Sheesh. Are we having fun yet?? Howard went to the meeting and reported that Caldicott said “If we relicensed Vermont Yankee, I will never come back to Vermont again.” (more or less quoted). Wow. Relicensing would give us a good future TWO different ways. Nuclear power AND no Caldicott visits.
Outrageous lies from Helen Caldicott:
Citing the acute effects of radiation on the rapidly dividing cells in children, Caldicott said the students of Vernon Elementary School, located adjacent to the plant, are in danger of exposure to radiation.
Quick! Evacuate VT, NH and upper state NY
Given that natural concentration of radioactive materials in the soils of the world far exceeds anything that may have leaked from VY, we need to evacuate the whole planet!
The radioactivities of the various components of coal ash/fly ash would be interesting for comparison purposes. I believe there is significant concentration of uranium and thorium in fly ash.
Fly ash has 10 to 30 ppm uranium, according to the only reference I can find.
http://pubs.usgs.gov/fs/1997/fs163-97/FS-163-97.pdf
However, I consider fly ash to be “weaponized.” That is, it is pretty small (they catch everything bigger than 2.5 microns) which means it can lodge in your lungs. Comparing the contents of a reactor or fuel pool or dry cask to fly ash assumes that delivery methods don’t count. Inhaling fumes of bleach would be bad for me. Having a bottle of bleach under my kitchen counter (locked when the grandkids come) is no big deal. Delivery counts.
I’ve been studying the French National Academy vrs the NAS view on the LNT hypothesis a bit lately. I like the NAS statement a bit better as it seems to be better written, although I would like the French view to ultimately prevail, because the French say no one should pay attention to LNT given recent data. Perhaps the problem with the writing style is the French document is the fact that it is a translation. I’m going to check out what the rest of the National Academies say. It is astonishing to me that there is disagreement at this late date at this high of a level. Although the NAS document states “radiation is one of the most thoroughly studied potential hazards to humans”, obviously, there is one hazard that has been studied in more depth and in greater detail.
Aside: There is nothing like this type of high level dispute between National Academies over climate science – the world’s Science Academies are totally unified about the gravity of the problem and what civilization needs to do. They have issued repeated joint statements directed to G8 leaders pleading with them to eliminate the emissions of fossil fuels. End of aside. (I love the way Rod puts these “asides” into his podcasts).
My point? I don’t see where it matters what view prevails in the end. One thing I’d like to see the NAS way of calculating radiation risk applied to is a shipment of bananas – how many excess solid cancers can be expected to develop as a result of each shipload of bananas entering the US? And the same for coal plant fly ash – how many extra tumours will develop, as the NAS states so clearly that they will, as a result of the hundreds of times greater exposure of the general public to ionizing radiation coming from coal plants than nukes? What about all that radioactive “fracked” natural gas? The regular old gas exposed consumers to 10 – 15 times the radiation that living next door to a nuke as the proverbial Fencepost Man would, what about this new stuff extracted from uranium ores like the Marcellus Shale?
Its criminal, really, that all this cancer is being caused, left and right, when we have nuclear technology at hand to dramatically reduce it.
PS. that article Meredith linked to says uranium 10 – 30 ppm PLUS thorium 10 – 30 ppm, so its 20 – 60 ppm uranium + thorium in the ash. 99.5 % of this fly ash is often captured and dumped, so that’s 0.5% emitted into the air around the plant. According to this article, http://www.ornl.gov/info/ornlreview/rev26-34/text/colmain.html , which calculates emissions as tons per coal plant per year and states each coal plant as of 1982 produces 5.2 tons of Uranium and 12.8 tons of thorium, if 0.5% of this is emitted as fly ash to the air, 52 pounds of Uranium and 128 pounds of Thorium are packaged up in tiny glass particles and shot high into the air by each US coal plant each year, all of them ready to be inhaled to get to work causing cancer right away. This sounds like a hell of lot more than picocuries.
Caldicott-isms,
– from an appearance at the Washington DC restaurant and bookstore “Busboys and Poets”, 11/3/2008, taped and aired by the producers of the podcast “Earthbeat”.
It was horribly tedious to listen to, but I did. I took notes. Actual words Caldicott uttered are in quotes:
We must close down every single nuclear power plant in this country and in the world. Anyone advocating even keeping any existing nuclear plants open is “insane”. The industry, and scientists, it appears, do nothing but emit “lies” about nuclear power.
Nuclear power is evil. Just using nuclear power for a few generations will cause this:
you can imagine, generations hence, people waking up in the morning, their babies have already been irradiated in utero, maybe been born deformed, or with genetic disease, the breast milk already radioactive, children getting cancer at the age of six instead of sixty, because they were exposed to radiation very early in life. And children are ten to twenty times more sensitive to radiation than adults
Nuclear power is: “evil because you don’t kill people to turn on your lights”.
You need to always remember that nuclear power is the prodigal son of the weapons industry. It’s splitting the atom, it’s producing energy, available inside the Sun
and obviously, no one wants that.
She even comments on the extra danger for us all now that someone mumbled “peak oil” at her somewhere: “how will our descendants transport huge vats of radioactive waste and radioactive fuel rods and the like WITHOUT ANY OIL to transport it? Imagine that.”
Since global warming is assured to cause sea level rise, Caldicott has a brand new concern:
many reactors are built at sea level, the seas are rising, the control rooms will be drowned. We’ll have meltdowns.
Obviously: “the people who want to build more reactors are insane. They need mental health therapy”