Posted on 03/29/2016 11:08:55 AM PDT by djf
One of the nuclear reactors at Hanford has had a scram. That means the cooling failed and the reactor automatically shut down.
The news reports say they are checking it out and will restart when it's safe.
I KNEW I’d somehow recognised him in Hunt.
Thanks!
The guy can play a lot of parts!
If you haven’t yet you must see “Clue”.
Well...I was saying that when an uncontrolled reaction (atomic explosion) is the goal, no controls are applied but rather the opposite (compression to critical mass).
The chief danger from a nuclear reactor has always been not an atomic explosion, but uncontrolled release of radioactive materials (as dramatized by Garrett Morris).
IMO the best safety measure is to not build a reactor over a tectonic fault.
We were taught it means, Sh*t! Cut the Rope Ax Man”
As in, lower the rods into the reactor asap.
I don’t think what is happening today has anything to do with earthquakes.
That’s really not quite right.
Radioactivity is the spontaneous decay of a nucleus, usually by alpha (helium nucleus), beta (electron), or gamma (electro-magnetic) emission, although several other forms can occur. Neutrons are rarely emitted by radioactive decay (although the emission of neutrons by radioactive decay is important in controlling a reactor).
Nuclear fission is the splitting of an atom using a neutron typically, resulting in two (or rarely three) atoms, roughly half the mass of the original atom and several neutrons (usually two or three). These released neutrons can then cause additional fissions, which would be a chain reaction.
A sustained chain reaction occurs when the splitting of one atom (usually uranium or plutonium) releases neutrons which cause the splitting of one additional atom.
An uncontrolled chain reaction may occur when the splitting of one atom releases neutrons which cause the splitting of more than one atom (which does not necessarily cause an uncontrolled chain reaction - when a reactor is started up, then the splitting of one atom causes the splitting of more than one additional atoms, but the process is easily controlled).
To control a chain reaction, one can employ several methods. Control rods in the reactor can be moved. Control rods are made of a neutron poison such as silver/indium/cadium or boron. A neutron poison such as boric acid can be manipulated. The coolant temperature or coolant flow can be changed. The leakage of neutrons out of the core (where they can no longer contribute to a chain reaction) can be changed. Carbon is definitely not a neutron sponge.
A problem is that those two atoms resulting from the splitting (fission) of the atom, mentioned above, are radioactive, meaning that they are giving off beta and gamma emissions and releasing energy. The amount of energy being released is about 7% of the reactor power, if the reactor were immediately shutdown. If the reactor was producing 3000 megawatts of energy (a typical amount) and was shutdown, then immediately after shutdown, it would still be producing 210 megawatts, even though the chain reaction has been stopped. The amount of this energy, known as decay heat, gradually diminishes after reactor shutdown.
However, it must be removed to avoid a core meltdown. Normally, the heat is removed using the reactor coolant system, at least initially after shutdown, although other cooling systems will be used as conditions allow following a shutdown.
The emergency core cooling system is used should the reactor cooling system for some reason not be available. The control rods have nothing to do with cooling the reactor. The emergency core cooling system is not a backup to the control rods.
A reactor scram or trip occurs when the reactor is abruptly shutdown. The control rods are inserted when a scram occurs. During a normal shutdown, the reactor power will be decreased in a planned manner, and the reactor may be scrammed when the power is sufficiently low.
Or a scram could occur at full power if conditions warrant.
The reactor at Hanford is a boiling water reactor, which is a common type in the United States and throughout the world. It is not a graphite reactor.
I’ll check it out, thanks!
“We were taught it means, Sh*t! Cut the Rope Ax Man””
Safety Control Rod Axe Man
A very good write up except ... prompt neutrons are a form of radioactivity from the decay of an unstable nucleus.
That means the cooling failed and the reactor automatically shut down.
Um, no that’s not what it means. It means Safety control rod axe man. In other words an emergency shut down of a reactor by inserting the control rods to stop the fission process.
There are many conditions of a reactor that may warrant a SCRAM. Stating a coolant loss issue without supporting facts is fear mongering.
My version is more colorful.... :P
The B Reactor at the Hanford Site, near Richland, Washington, USA, was the first large-scale nuclear reactor ever built. The project was commissioned to produce plutonium-239 by neutron activation as part of the Manhattan Project, the United States nuclear weapons development program during World War II. The B reactor was fueled with metallic natural uranium, graphite moderated, and water-cooled.
The Chernobyl reactor complex just 80 miles north of Kiev, Ukraine is made up of four Russian made RBMK-1000 water-cooled graphite moderated reactor designed to make plutonium for nuclear weapons and modified to also produce electricity. There are 27 RBMK's in the former Soviet Union. One distinguishing feature of the RBMK design is its use of graphite to slow the neutrons produced by the fissioning of uranium-235 atoms. Besides the RBMK reactors, the U.S. Department of Energy operated a graphite-moderated reactor at Hanford, Washington for the dual purpose of producing military plutonium and electricity up until the aftermath of the Chernobyl accident. Within the reactor core of a RBMK, nuclear fuel is placed in long separate vertical channels surrounded by graphite, which is expected to absorb large amounts of heat as a safety feature to give reactor operators ample time to take corrective action in the event of an accident. No More Chernobyls
The N reactor is graphite moderated also.
“OK, reloaded”
OBVIOUSLY YOU DIDN’T CLICK ON MY LINK ...
“The B Reactor “
Uh, the B reactor was shutdown in 1968, ergo it could not be operating now!
Hey, I just saw a girl in a sport ute headed out 240 at 100 MPH in the opposite direction
MANUAL SCRAM FOLLOWING LOSS OF REACTOR CLOSED COOLING
"At 1322 PDT on Monday, March 28, 2016, Columbia Generating Station was manually scrammed from 100% thermal power due to the loss of Reactor Closed Cooling (RCC). Manual scram of the unit is procedurally required upon loss of RCC. The cause of the loss of RCC is being investigated.
"Regulation 10 CFR 50.72(b)(2)(iv)(B) requires reporting within 4 hours of any event or condition that results in actuation of the Reactor Protection System (RPS) when the reactor is critical.
"All control rods were fully inserted. Valve RWCU-V-4 automatically closed upon high water temperature due to loss of RCC flow. No other safety system actuations were reported. All systems operated as expected. Reactor decay heat is being removed via bypass valves to the Main Condenser. The station is in normal shutdown electrical lineup.
"The NRC Resident Inspector has been informed."
No safety/relief valves lifted and no emergency core cooling systems injected following the reactor scram.
Thank you for an informative post as opposed to what passes for “journalism”.
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