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Nebraska nuclear plant thread.

by HowlerMonkey
Tags: nebraska, nuclear, plant
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Orcas George
#37
Jun26-11, 11:53 PM
P: 20
This is what drives me nuts about the circle the wagons mentality whenver there is a nuclear "oopsie".

The Omaha Public Power District has said the complex will not be reactivated until the flooding subsides. Its spokesman, Jeff Hanson, said the berm wasn't critical to protecting the plant but a crew will look at whether it can be patched.

"That was an additional layer of protection we put in," Hansom said.
OK, so this dam wasn't important or anything, they just put it in there as a backup. Redundancy, multiple lines of defence, defence in depth and all that good stuff.

The berm's collapse didn't affect the reactor shutdown cooling or the spent fuel pool cooling, but the power supply was cut after water surrounded the main electrical transformers, the NRC said. Emergency generators powered the plant until an off-site power supply was connected Sunday afternoon, according to OPPD.
Somehow that negates the idea that this was a non-critical backup just to be on the safe side...
NUCENG
#38
Jun27-11, 05:00 AM
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Quote Quote by Orcas George View Post
There is a lot more water in the system than in normal times so the dam is near maximum capacity. That has more to do with anything than differential pressure which isn't usually a factor.

There are a lot of things involved in a flood; the change in force from a normal river to one at flood stage is something that has to be seen to be believed. There a lot of debries upstream that wants to come dow and it tends to collect into a large mass. Earth berms get soaked and the dirt looses its cohesion. Water going over the top of a dam quickly erodes even concrete. Temporary dams of junk form and suddenly release, which can increase the force in the system briefly and cause break throughs.


It is easy to underestimate what a couple of feet of water can do (ask the Japanese about that one.) Never drive through a flooded street, nor go kyaking on a flooded river. (I drove over a flooded bridge once which turned out not to be the smartest move of my life; if you can't be good be lucky...)
Thank you,. I claim no expertise in civil engineering, and that is a little counter-intuitive. If the dam is near capacity are they releasing water?
NUCENG
#39
Jun27-11, 05:02 AM
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P: 916
Latest event report updates:

http://www.nrc.gov/reading-rm/doc-co.../event/en.html
zapperzero
#40
Jun27-11, 06:11 AM
P: 1,042
Quote Quote by NUCENG View Post
Thank you,. I claim no expertise in civil engineering, and that is a little counter-intuitive. If the dam is near capacity are they releasing water?
Releasing water to where, exactly? I mean, what are you asking?
zapperzero
#41
Jun27-11, 06:30 AM
P: 1,042
Slightly(?) offtopic. Minot is being flooded.
http://abcnews.go.com/US/minot-north...ry?id=13913535
Minuteman III nuclear missile silos are also in the flood's path. At least two silos are being protected by sandbags and pumps, but are reported to be safe.
Joe Neubarth
#42
Jun27-11, 10:11 AM
P: 238
Quote Quote by zapperzero View Post
Slightly(?) offtopic. Minot is being flooded.
http://abcnews.go.com/US/minot-north...ry?id=13913535
Minuteman III nuclear missile silos are also in the flood's path. At least two silos are being protected by sandbags and pumps, but are reported to be safe.
Nothing to worry about there. If the silos are flooded the missiles can not launch. I would expect that the warheads would have been removed days before any serious flooding scenario, but even if they weren't, they would cause no problem other than the fact that they would have to be retired from present service and ten tons of paperwork would have to be filed with all of the military agencies that would be involved. I was a Nuclear Weapons Officer at one time. Believe me, you do not want to do that paperwork.
Orcas George
#43
Jun27-11, 10:23 AM
P: 20
Quote Quote by NUCENG View Post
Thank you,. I claim no expertise in civil engineering, and that is a little counter-intuitive. If the dam is near capacity are they releasing water?
Yes, which is why it is flooding downstream of the dam(s). The odd thing to realize is that these floods are "controlled"; the engineers have to make the heartbreaking decision to flood the towns downstream in order to prevent an uncontrolled dam collapse. Obviously the natural tendancy is to hold off doing it as long as possible in hopes that it stops raining but the longer you wait the worse it gets if you have to do it. This is one reason why NOAA (the national weather forecasting office) is such a critical resource to the country.
Joe Neubarth
#44
Jun27-11, 10:29 AM
P: 238
Quote Quote by NUCENG View Post
Thank you,. I claim no expertise in civil engineering, and that is a little counter-intuitive. If the dam is near capacity are they releasing water?
In the overwhelming majority of dams I have seen close up, the spilling of water when they reach rated capacity is usually built right into the dam design, with the spillway designed to carry any water in excess of the rated maximum water height limit. I suppose you could sand bag the tops of the spillways to try to retain more water if you wanted to.

Off topic. It is a shame that we can not divert that flood water every spring to west of the Rockies. We sure could use it in the states further west. We could actually put people to work in agriculture in Arizona, Nevada, and California if only we could get it to the Colorado River.
robinson
#45
Jun27-11, 11:07 AM
P: 201
The dams are supposed to used for flood control. There is much irony that they have led to the record flooding instead.
zapperzero
#46
Jun27-11, 11:09 AM
P: 1,042
Quote Quote by Joe Neubarth View Post
Nothing to worry about there. If the silos are flooded the missiles can not launch. I would expect that the warheads would have been removed days before any serious flooding scenario, but even if they weren't, they would cause no problem other than the fact that they would have to be retired from present service and ten tons of paperwork would have to be filed with all of the military agencies that would be involved. I was a Nuclear Weapons Officer at one time. Believe me, you do not want to do that paperwork.
I don't think it's any sort of danger either. The thought of those missiles maybe drowning in mud made me giggle a bit, in fact, unlike that other little mishap at Minot a few years ago which still gives me the nuclear heebie-jeebies whenever I think about it.
Astronuc
#47
Jun27-11, 11:14 AM
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Quote Quote by NUCENG View Post
The one specific to Ft. Calhoun is # 46988

http://www.nrc.gov/reading-rm/doc-co...n.html#en46988

See also -
http://www.world-nuclear-news.org/RS...d_2706112.html
NUCENG
#48
Jun27-11, 12:03 PM
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P: 916
Quote Quote by zapperzero View Post
Releasing water to where, exactly? I mean, what are you asking?
In past years I have been in areas with flooding and was always told the worst thing for a dam is "over-topping" or water overflowing the dam itself. So most dams in this area have spillways to allow flow downstream to prevent that condition which could lead to dam failure. My understanding, may be wrong, so I'm asking if the dam upstream of Ft Calhoun is releasing water?
robinson
#49
Jun27-11, 12:05 PM
P: 201
All the dams are releasing water. If an old earth fill/chalk damn is over topped it will fail. They have the spillways full open and are praying nothing more will happen.
NUCENG
#50
Jun27-11, 12:10 PM
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Quote Quote by Astronuc View Post
I heard a report this morning on TV that they reconnected one line of offsite power to Ft Calhoun. Any confirmation?
Joe Neubarth
#51
Jun27-11, 07:39 PM
P: 238
Quote Quote by zapperzero View Post
I don't think it's any sort of danger either. The thought of those missiles maybe drowning in mud made me giggle a bit, in fact, unlike that other little mishap at Minot a few years ago which still gives me the nuclear heebie-jeebies whenever I think about it.
That incident was embarrassing to the Air Force but not THAT dangerous unless the plane carrying the weapon system crashed. Of course that can happen any time you transport a weapon via air in cargo planes. Weapons being returned are supposed to be separated from their delivery vehicle. In this case the young men involved did not understand that and just shipped the whole assembly on the wing of a plane back to the facility where they had the capacity to remove the weapon.
Drakkith
#52
Jun27-11, 08:16 PM
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Quote Quote by Joe Neubarth View Post
That incident was embarrassing to the Air Force but not THAT dangerous unless the plane carrying the weapon system crashed. Of course that can happen any time you transport a weapon via air in cargo planes. Weapons being returned are supposed to be separated from their delivery vehicle. In this case the young men involved did not understand that and just shipped the whole assembly on the wing of a plane back to the facility where they had the capacity to remove the weapon.
The issue was the result of a number of people assuming that the multiple required checks to ensure that no weapons were inside the missiles were done and that "there's no way everyone didn't check this already". Which in fact was what happened. We have a term for that in the Air Force: Complacency. The people involved never knew the weapons were even loaded until after the plane landed and the weapons were found.

The weapons themselves were never in any danger, like you said, but as seen in the past B-52's do crash, so better safe than sorry!
Joe Neubarth
#53
Jun27-11, 11:27 PM
P: 238
Quote Quote by Drakkith View Post
The issue was the result of a number of people assuming that the multiple required checks to ensure that no weapons were inside the missiles were done and that "there's no way everyone didn't check this already". Which in fact was what happened. We have a term for that in the Air Force: Complacency. The people involved never knew the weapons were even loaded until after the plane landed and the weapons were found.

The weapons themselves were never in any danger, like you said, but as seen in the past B-52's do crash, so better safe than sorry!
When I went through Nuclear Weapons School they told us to NEVER sign off on anything unless we are absolutely certain that it has been done according to the book. That screw up in the Dakotas was a perfect example of young people trying to brush off the paperwork.

An age old Military axiom comes to mind: "You get what you INSPECT."
Drakkith
#54
Jun28-11, 01:17 AM
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Quote Quote by Joe Neubarth View Post
When I went through Nuclear Weapons School they told us to NEVER sign off on anything unless we are absolutely certain that it has been done according to the book. That screw up in the Dakotas was a perfect example of young people trying to brush off the paperwork.

An age old Military axiom comes to mind: "You get what you INSPECT."
Take the "Young" out of "Young People" and you've hit that on the head.


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