Following up on yesterday's post about the status of a nuclear power plant in the path of Hurricane Katrina, a BB reader whose father is a longtime employee of the plant's operator says:
Alright, nobody seems to want to speak plain English, but from what I can put together, the plan is ready to get running, but FEMA won't let them. It has something to do with FEMA's requirements for exacuation plans and such.
Speaking of FEMA (…) I know they threw people out of a hotel (when they previously said do not leave the hotel if you're in one) to make room for themselves.
They also have 0 presence in East Biloxi, where residents have turned a church into an Emergency Aid Center.
The people in charge say a FEMA rep came by the second day in, the never came back. The FEMA head is saying they "don't want to bring in to many people and harm the infrastructure."
Previously:
update on New Orleans nuke plant status
Reader comment: Harlan says,
Here is the link for archived Nuclear Regulatory Comission events.
On September 1st, one update reads:
"Waterford 3 will commence a plant shutdown to Mode 4 on August 28, 2005 at 1100 CDT. The goal is to be approximately 325 deg F reactor coolant system temperature with both trains of Shutdown Cooling in service [expected at approximately 0100 CDT 08/29/05] . This is approximately 2 hours before hurricane force winds are expected on site."
Also, the current power level of reactors is listed here. Waterford is naturally at 0. PS For the non-nuclear geeks, the vast majority of the events are nothing. Their reporting level is akin to doing a reboot for a typo, and a format/reload for a floppy error.
Reader comment: Eric McErlain, Senior Writer for the Nuclear Energy Institute and Editor of NEI Nuclear Notes says:
Xeni, saw your item on the Waterford nuclear plant, and thought you might want to see the series of blog posts we've done following the events in the gulf:
Entergy Copes with Katrina Damage, Entergy and Southern Company Boincing Back.
Here are the NRC releases on their activities in the Gulf area regarding Waterford and other plants in the area: one, two.
And here's the AP story on the potential plant restart: Link.
Reader comment: Phil Camp, Jr., who knows a hell of a lot more than me about nuclear energy, says:
Reactors work by the chain reaction of fissioning (splitting) Uranium atoms into pieces, two or more "daughter" nuclei plus typically two to five neutrons per reaction. All nucleons (protons & neutrons ) attract each other much more strongly than the electric repulsion between protons (protons all have a + charge while neutrons have none), but the nuclear force has a very limited range, becoming exponentially weak at a distance not much bigger than a proton's diameter. Because of this, as nuclei go to higher atomic numbers, they need to have many more neutrons than protons to stay together. So the atomic wieght (total # of neutrons & protons) goes up more than twice as fast as the atomic number (number of protons). Examples: Oxygen, O16, has 8 each; Iron, Fe56, has 26 protons and 30 neutrons, and U235 has 93 protons and 142 neutrons.
But if a nucleus has too many neutrons, it will eject some or turn one into a proton + electron, eject the electron (called a beta ray), and bump its atomic # up one. So when U235 breaks up, there are extra neutrons ejected, which would be of little interest except that U235 just happens to fission when it absorbs a neutron, and so we get the chain reaction.
Now some of the daughter products are unstable and decay into nuclei which absorb neutrons. This slows down the reaction, but these are created only slowly, so the continued neutron flux neutralizes them.
When the reaction stops though, they build up. Many of them are unstable themselves, but have much longer half lives, so if you wait too long, the fuel rods become "poisoned" (from a nuclear standpoint now), and the reactor won't start up again till you let the poisons decay (long time) or replace the rods (mucho $). On naval reactors this is about a week, but they are pretty small; the deadline is probably longer with the big commercial reactors, but they may be in trouble if they wait too long.
Reader comment: Eric McErlain of nei.org says,
Xeni — saw the update with the comments about the decay of fuel rods and their affect on the Waterford re-start. I showed the post to one of our fuel experts, Felix Killar, and this is what he wrote in response:
In commercial reactors the time for restart following a reactor shut down is dependent on where it was in the operating cycle when it was shut down. Commercial reactors refuel every 18 to 24 months while naval reactors are fueled for the life of the vessel (well over 20 years). As a result the commercial reactor has about 1/3 fresh fuel in it which has less then one operating cycle, this provides excess neutrons if needed to restart the reactor and fewer fission products that absorb neutrons.
However, even with this, if the reactor is close to the end of the cycle there may not be sufficient neutrons to restart the reactor with out a long waiting period. The waiting period allows for some of the neutron absorbing fission products to decay to non-absorbing fission products.
If the reactor is shut down early in the cycle it can be restarted within hours to days without any problems. If it is in the end of the cycle it will be days to weeks before it can be restarted. If a shutdown were to occur close to the end of the operating cycle, due to the delay to restart, the reactor may go into refueling rather then restart.
The replacement of the fuel is expensive, however, the loss of the power production is expensive as well. Therefore, the opportunity costs are considered in making the decision to wait to restart (and pay replacement power costs) vs. going into an early refueling (and losing some of the energy in the 1/3 of fuel that will be removed.)
