Monday, January 30, 2012

Update on Byron Nuclear Plant: Diesel Generators Used for Vent, Excelon Says Tritium Is Natural

From Rockford Register Star (1/30/2012 8:43PM):

ROCKFORD — A loss of power coming into the Byron nuclear plant caused one of two reactors to automatically shut down about 10:15 a.m. today.

Backup diesel generators were activated after the power outage and were being used for safety equipment that vents heat from the reactor, according to a spokeswoman from the Nuclear Regulatory Commission in Lisle.

“Right now, we believe the plant is in a stable condition,” said the NRC’s Viktoria Mitlyng. “There is no danger to the workers or the public.”

Exelon, which operates the Byron plant, declared an “unusual event” — the lowest of four emergency classifications established by the NRC — after the outage.

Mitlyng said two NRC resident inspectors are monitoring the plant.


Byron station spokesman Paul Dempsey said crews are still trying to determine how power coming to the generator was interrupted. The steam release, which he said made a whooshing sound, was expected to continue into the evening.

The steam contains tritium, a hydrogen isotope with low levels of radioactivity. Exelon, in a news release, said tritium occurs naturally and is found in virtually all surface water, although it is found in greater concentrations near nuclear reactors.

It was the first automatic shutdown of the plant since 2007 when a dime-sized hole in a water cooling pipe led to the shutdown of both reactors.

(Full article at the link)

They all say the same thing. It is safe, radioactive materials are natural. Soon they'll be talking about bananas and transcontinental flights and X-rays.

From wiki on tritium from fission:

Tritium is an uncommon product of the nuclear fission of uranium-235, plutonium-239, and uranium-233, with a production of about one per each 10,000 fissions.[7][8] This means that the release or recovery of tritium needs to be considered in the operation of nuclear reactors, especially in the reprocessing of nuclear fuels and in the storage of spent nuclear fuel. The production of tritium was not a goal, but is rather just a side-effect.


Anonymous said...

Whooshing steam continuing through the evening...Followed by some light rain tomorrow.

Yes, that is the extent of the local news coverage.
Not one single channel/report asked what the volume of the release was/is and importantly what other elements are in that steam, and the concentration of those.

It's a little tritium.
It's safe.
They said so.

Feeling a little dangerous, think I'll go eat a banana

Atomfritz said...

Ahh, yes.

Next time they will tell us that radioactive Cesium is also natural because you can find astronomically minute trace quantities in uranium metal. Like plutonium and other "natural" elements.

Anonymous said...

Good to know that Tritium is natural, otherwise I might have become concerned. I am just waiting for a NRC spokesperson to say the people next to the plant should smile more....

By the way, a malignant tumour is also natural and it is natural to die. So do not worry and keep smiling, everything is natural...

Anonymous said...

"aid crews are still trying to determine how power coming to the generator was interrupted."

This sounds alarming, Was he referring to the turbine generator(s) or the Diesel generator(s). interruption of power from the Diesel generators is very concerning since its the only lifeline to keep the coolant flowing.

I recall another news article about this incident that mentioned smoke was seen from the transformer yard, which means that a electrical component failure occured. Perhaps one of the transformers failed.

I really wish the modified the shutdown policy to keep the turbines running until they have confirmation that the diesels are running and they have the reactor temperature under control. The problem is that it can take a while to restart the steam turbines after they shut them down. Using the turbines to power the plant during a cool down cycle seems more prudent method. Keep the turbines spooled up in an event that the plant loses grid power provides a backup to the backup diesels incase something malfunctions (transfer switch, problem with the diesels, or some other electrical problem)

Greyhawk said...

Naturally occurring tritium is extremely rare on Earth. It is carcinogenic. Exelon is lying. Period.

Steve From Virginia said...

Tritium in the turbine loop means a leak in the reactor heat exchanger.

You bet they will cover that up b/c repairing or replacing the heat exchanger is massive job.

It also means the leakage from steam primary into turbine circuit has been ongoing, there is no reason why not.

If Tritium emission is high it also means fuel rod cladding is compromised w/ leakage from fuel elements.

Words of wisdom from my brother the plumber: "if man builds it, it will leak."

Half life is 12 years so it persists for over a century in your back yard.

Steve From Virginia said...

Morgaine said...

It turns out the problem that interrupted power was a broken insulator.

From Associated Press:

"Illinois reactor shutdown blamed on bad insulator
CHICAGO (AP) — A failed electrical insulator in a switchyard was to blame for the power failure that caused one of Exelon Energy's nuclear reactors in northern Illinois to shut down, company officials said Tuesday....
.....The insulator, a piece of protective equipment that helps regulate the flow of electricity in the plant's switchyard, failed Monday morning and fell off of the metal structure to which it was attached. That interrupted power and caused the reactor to shut down automatically as a precaution.
It was not immediately clear what caused the insulator to fail, but the part will be sent to a lab for analysis, Dempsey said."


If you haven't seen a "proximity-to-normal-folks" image of Byron venting, here's one from March 2011:

BTW, does anyone know what the white blotches/squares are in the photo? Perhaps it's the tritium they swept up that morning...


Morgaine said...

About tritium...I vote with Greyhawk. They are lying.

This is a Greenpeace/NIRS document. There are two new realizations I obtained from this report.

1. I started paying serious attention at page 7. Quote from page 8 raises an issue I am finding on reviewing info about tritium: the studies are mostly about "HT" and not "OBT." This Greenpeace report describes the significance of this better than I can:

"Organically bound tritium (OBT)
OBT is tritium which has become chemically attached to carbon atoms3 in organic molecules.
Organic binding is tritium’s most significant property, but, unfortunately, official dose models
for OBT underestimate its hazards.
Humans can accumulate OBT in two ways. The first is by consuming OBT in food, e.g.,
vegetables, wheat, honey, milk, that has been grown and harvested in areas near Candu
reactors contaminated by tritiated water vapour. The second is by drinking/eating, breathing,
and absorbing tritiated water that then is then both metabolised into organic molecules
needed by the body, and incorporated into new cells.
OBT is more problematic than HTO for two reasons. First because OBT’s residence time (i.e.,
half-life) in humans is much longer (20 to 50 times) than HTO’s residence time (see Part 2 of
this report). And second because OBT must by definition be located near organic molecules
(such as DNA) more often than HTO. As stated by Taylor et al (1990) ”... the concentration of
OBT in tissues of interest, are greater by up to an order of magnitude after ingestion of OBT
than after HTO ingestion...”. This means that radiation exposures from OBT are much larger
than that from HTO."

2. The other thing I learned from this report that I didn't know before is this: in the land of radiation biology, the weaker the decay particle, the more effective it is in causing damage to us. How many times have you seen a radionuclide decay particle described in a newspaper or by Tepco as "weak" did you see the disclaimer, "BTW, with decay particles, the weaker (less energy they produce) the more damaging they are to us"? Me? Never.

Here's a quote from the Greenpeace/NIRS report:

"However, some
radiation authorities continue to assert, rather misleadingly, that tritium is a “weak” radionuclide
because the energy of its decay particle is very low. However, paradoxically, in radiation biology
the weaker a particle the more effective it becomes. Unfortunately this remains unrecognised in
official circles and tritium’s official dose factor (i.e., the dose given by the disintegration of one
atom of tritium) is currently very small."

Anonymous said...

"in the land of radiation biology, the weaker the decay particle, the more effective it is in causing damage"

Usually its because there are more abundant. Most of the fission products give off alpha and beta radiation. Outside the body, they cause little damage. However if they are inside the body (inhaled or ingested) they do a great deal of damage. Outside the body its the high energy gammas that are the concern since they can easily penetrate clothing and skin.

Alpha particles are the nuclei of helium atoms had bounce off human skin. Beta Particles are ejected electrons from a decaying neutron particle. These are ejected at very high speeds and because of there small size they can penetrate up to a few millimeters below the skin. Gamma rays are ultra-high energy light particles. They are like x-rays only with a much shorter wavelength, these can penetrate throw the entire body and some gamma radiation can penetrate more than a meter of solid lead.

Tritium emmits beta radiation. Internal expose from tritium is bad. Most tritium is bound up in water, where it can be inhaled or ingested. Tritium originates from the reactor water as neutrons from fission are absorbed by the hydrogen atoms in water. It doesn't have anything to do with the fuel rod jacket being compromised.

In the end it not so much significant the energy emissions of exposure. Its all harmful and should be avoided.

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