Can a nuke power plant just blow up?

  • Thread starter alancj
  • Start date
  • #1
58
0
Ok, I was watching the movie "Resident Evil: The Apocalypse" the other day. The big evil "Umbrella Corporation" nukes a city to kill the T virus (which is what makes the people turn into zombies :surprised ) The cover up for the city getting vaporized is too just say that the local nuclear power plant had a meltdown. I laughed because I don't even think it’s possible for a power plant to just detonate like that. Don't you need highly specific conditions in order to get that kind of a nuclear explosion; something that purposely cannot be met in a nuclear reactor?

-Alan
 

Answers and Replies

  • #2
151
0
It took a lot of smart people many years to make the first nuclear bombs. It's not something that just happens. Probably the worst-case scenario for a reactor would be a steam-explosion, like Chernobyl. It was enough to blow chunks of the reactor core through the roof of the reactor building. Unlike Chernobyl, all commercial reactors in the US have a large steel-reinforced concrete containment building around the reactor core meant to contain such an explosion, so even that type of scenario is very unlikely.
 
  • #3
Pengwuino
Gold Member
5,009
16
I think he meant the real whole nuclear explosion type deal which is impossible. You'd need to introduce a tremendous number of neutrons very very quickly to create an explosion I believe.
 
  • #4
58
0
Pengwuino said:
I think he meant the real whole nuclear explosion type deal which is impossible. You'd need to introduce a tremendous number of neutrons very very quickly to create an explosion I believe.
Exactly what I thought...
 
  • #5
Astronuc
Staff Emeritus
Science Advisor
19,843
3,329
Pengwuino said:
I think he meant the real whole nuclear explosion type deal which is impossible. You'd need to introduce a tremendous number of neutrons very very quickly to create an explosion I believe.
One could have a prompt critical event, but not like a nuclear warhead. The critical mass in a warhead is nearly pure fissile material and then it is compressed (density increased above normal).

Likely in a nuclear reactor, the prompt event could initiate a pressure pulse which, if strong enough, could cause piping to rupture, or perhaps the pressure vessel to rupture, but then the coolant (assuming water) would flash to steam and one would have a thermal/steam explosion, not a nuclear explosion.

However, introducing sufficient reactivity, by say removing all control rods rapidly is essentially physically impossible.
 
  • #6
It is impossible to have a nuclear explosion.

The uranium in nuclear reactors a mixture of U235 and U238, where U235 is only a small percentage, in order to control the reaction.
 
  • #7
30
1
You can have a steam explosion.

But a nuclear one? No. The uranium used in reactors is not enriched enough.
 
  • #8
58
0
Well, I guess I shouldn't expect too much from a movie like that. I hate plot holes though; and I think that that movie had some to spare...
 
  • #9
PerennialII
Science Advisor
Gold Member
900
1
alancj said:
Well, I guess I shouldn't expect too much from a movie like that. I hate plot holes though; and I think that that movie had some to spare...

........ perhaps they wanted to explain the casualties and not the event itself, it's not like people are lining up to see the results anyways :rolleyes: .
 
  • #10
58
0
PerennialII said:
........ perhaps they wanted to explain the casualties and not the event itself, it's not like people are lining up to see the results anyways :rolleyes: .
No, it was supposed to cover up the nuclear bomb that they drooped on the city. Which is basically what the characters said in the movie, "they’ll nuke Raccoon City with a 5 kiloton bomb and say it was a meltdown at the nuclear power plant."

Pretty freaking dumb…

-Alan
 
  • #11
Pengwuino
Gold Member
5,009
16
alancj said:
No, it was supposed to cover up the nuclear bomb that they drooped on the city. Which is basically what the characters said in the movie, "they’ll nuke Raccoon City with a 5 kiloton bomb and say it was a meltdown at the nuclear power plant."
-Alan

Yah, no one except 99% of hte general public would believe that crap.

On a related note... some science show (on a reputable channel!) was talking about fusion experiments such as ITER. They were saying that there was a possibility that a fusion test reactor like ITER or the NIF could blow up when started in a small thermonuclear explosion. They can't be using that much fuel could they???
 
  • #12
Morbius
Science Advisor
Dearly Missed
1,125
6
Pengwuino said:
On a related note... some science show (on a reputable channel!) was talking about fusion experiments such as ITER. They were saying that there was a possibility that a fusion test reactor like ITER or the NIF could blow up when started in a small thermonuclear explosion. They can't be using that much fuel could they???
Pengwuino,

With respect to NIF - that sounds like the same fear mongering that the local anti-nuclear
group "Tri-Valley CARES" has been spreading.

For example, LLNL recently enhanced its security by adding Dillon Aero M134 Gatling
guns to the Lab Protective Force's arsenal of weapons:

www.llnl.gov/pao/com/2006/spring_discover_llnl.pdf[/URL]

The M134 fires depleted uranium rounds. The anti-nukes leafeted the houses near
the Lab, including mine; stating that if they shoot those guns then my house will be
radioactive for 1,000 years [ where they got that number, I don't know - it has
nothing to do with the 4.5 Billion year half-life of the U-238 in depleted uranium] and
that my house value is now zero. I won't be able to sell my house.

The anti-nukes are so self-righteous that they believe they can tell any type of lie
they want in order to further their cause.

Dr. Gregory Greenman
Physicist
 
Last edited by a moderator:
  • #13
151
0
Morbius said:
stating that if they shoot those guns then my house will be radioactive for 1,000 years [ where they got that number, I don't know - it has nothing to do with the 4.5 Billion year half-life of the U-238 in depleted uranium]

A lot of those folks don't do big numbers. I guess anything over 1000 is all the same to them. Too bad the ones protesting Yucca Mountain can handle the large numbers better. :grumpy:

One of the saddest 'facts' I ever saw on one of those 'DU is destroying the world' type webpages was this: "IN A SINGLE GRAM OF URANIUM-238, THERE ARE MORE THAN 12,000 RADIOACTIVE DECAYS PER SECOND!!!!!!!!!" (not sure about the number of exclamation points.) It was sad because the number is correct, and the person who sat down and computed the specific activity surely knew 12,400 decays per second is miniscule. A gram of Technetium-99m, which is regularly injected into people for diagnostic tests, has a specific activity of ~2x1017 decays per second. They just chose to portray the facts in a way that would scare uneducated people.
 
  • #14
Morbius
Science Advisor
Dearly Missed
1,125
6
Grogs said:
They just chose to portray the facts in a way that would scare uneducated people.
Grogs,

Exactly!! Nuclear technology is not something that is taught as part of the "general
education" one gets in K-12 schooling. Since people don't know anything about the
technology - it is easy to scare them by telling them it does something it doesn't -
like blow up.

Dr. Gregory Greenman
Physicist
 
  • #15
In the movie "K-19: The Widowmaker" a Russian nuclear submarine reactor malfunctions and (in the movie) the crew was worried about a minor explosion triggering warheads aboard. I was always under the impression for the warheads to work they must go through specific steps.( like a gun-triggered fission bomb for example)
 
  • #16
NateTG
Science Advisor
Homework Helper
2,450
6
The hard part is getting the fissible material. The gun-barrel designs can be quite simple - they can be triggered by a single explosive charge. (Implosion designs tend to be more complicated.)

Generally, nuclear plants are designed to fail in a less catastrophic fashion.
 
  • #17
Morbius
Science Advisor
Dearly Missed
1,125
6
Vincent Vega said:
In the movie "K-19: The Widowmaker" a Russian nuclear submarine reactor malfunctions and (in the movie) the crew was worried about a minor explosion triggering warheads aboard. I was always under the impression for the warheads to work they must go through specific steps.( like a gun-triggered fission bomb for example)
Vincent,

Yes - at least the USA's weapons, and I assume the Soviet weapons, have "locks" on
them. Some are known as PALs - "Permissive Action Links".

The weapons are locked so they can't be detonated in an accident, and a rogue
military officer can't launch a nuke without orders. For example, on USA Trident subs
the "Captain's missile key" is not in the possession of the boat's skipper. It is locked
in a safe. Nobody on board has the combo to the safe. The combo to the safe is
received as part of the order to launch. For more on this see the book "Big Red":

https://www.amazon.com/gp/product/0060194847/?tag=pfamazon01-20

Dr. Gregory Greenman
Physicist
 
Last edited by a moderator:
  • #18
Morbius
Science Advisor
Dearly Missed
1,125
6
NateTG said:
The hard part is getting the fissible material. The gun-barrel designs can be quite simple - they can be triggered by a single explosive charge. (Implosion designs tend to be more complicated.)

Generally, nuclear plants are designed to fail in a less catastrophic fashion.
Nate,

It's not quite as simple as you make it out to be.

Dr. Gregory Greenman
Physicist
 
  • #19
Astronuc
Staff Emeritus
Science Advisor
19,843
3,329
NateTG said:
Generally, nuclear plants are designed to fail in a less catastrophic fashion.
:rofl: Generally, nuclear plants are designed NOT to fail!!!!!
 
  • #20
lol I love the RE movies, I dont care what people say about them!
Anywho, nuclear reactors employ moderators (like heavy water, carbon, etc) that absorb the neutrons from the fuel (Uranium or Plutonium). By absorbing neutrons, a chain reaction cannot occur causing a powerplant to explode. As previously and correctly stated in earlier posts, the fuel is not nearly enriched enough (you need it to be about 80-odd% enrichment, I think).
To my understanding, one of the factors leading to Chernobyl was because one of the technicians pulled out the moderator ---> chain reaction --->boom (well, implosion).
[Feel free to correct me, if I got anything absurdly wrong]
I suppose it just goes to show how misconceptions are purveyed in a society that is very nuclear-illiterate. :cool:
 
  • #21
396
2
I do not think enrichment in reactors is so high. I recall it is closer to 5~6% w/o U-235. Also, the way I understand it, the moderator in Chernobyl was not removed, but instead because of the positive void coefficent of the reactor, it ceased moderating as well as it should have (basically the density of the moderator decreased, and the cross section of the moderator along with it).
 
  • #22
Astronuc
Staff Emeritus
Science Advisor
19,843
3,329
The maximum allowable U-235 enrichment in commercial nuclear fuel is 5%, but that usually means 4.95% to allow for uncertainty. This limit is generally applied world-wide in the nuclear power industry.

In Chernobyl, control elements were being moved with protection systems disabled, since I believe the maneuver should have activated the protection systems. Anyway, the power increased too rapidly to respond, and the coolant (pressurized water) changed phase from liquid to steam, which in the graphite-moderated RBMK added more reactivity to the reactor - which led to a rapid power excursion and steam explosion.
 
  • #23
Morbius
Science Advisor
Dearly Missed
1,125
6
Astronuc said:
The maximum allowable U-235 enrichment in commercial nuclear fuel is 5%, but that usually means 4.95% to allow for uncertainty. This limit is generally applied world-wide in the nuclear power industry.

Small research reactors which used to run on fuel with high enrichment are now mostly
limited to 20%. The enrichment used by naval warships is still high.

In Chernobyl, control elements were being moved with protection systems disabled, since I believe the maneuver should have activated the protection systems. Anyway, the power increased too rapidly to respond, and the coolant (pressurized water) changed phase from liquid to steam, which in the graphite-moderated RBMK added more reactivity to the reactor - which led to a rapid power excursion and steam explosion.

At Chernobyl, the operators were planning an experiment with the reactor when it
was going to shutdown for an outage. They lowered the power of the reactor in
preparation for doing the experiment. However, before they began the experiment,
the electric load controller in Kiev called them and asked that they remain online
for a few hours more. The plant stayed online for about another 12 hours at this
lowered power level. It was then that the operators began their previously planned
experiment.

However, whenever you shutdown or lower the power level in a reactor, there is a
temporary buildup of Xenon-135, which is the radioactive daughter product of the
fission fragment Iodine-135. The reactor undergoes what is called a "Xenon
transient" because Xenon-135 is THE world champion neutron absorber!!! If
memory serves, it has a thermal absorption cross-section of 6 Million barns.

At the time of the accident, about 12 hours after power was reduced; the Chernobyl
reactor was right in the middle of the Xenon transient - right when Xenon concentration
peaked. The Xenon "poisons" the reactor, and makes it difficult to control and stay
in operation.

In fact, in order to keep the reactor working - the operators had to completely remove
ALL control rods from the reactor - in violation of approved operating procedures.
With the reactor in this VERY unstable state, with Xenon poisoning, and control
rods withdrawn - the operators began their experiment. The experiment required that
the operators disable the reactor safety systems, as they would prevent the
experiment from being conducted.

Nobody ever planned on doing this experiment in the middle of a Xenon transient
with all control rods removed, and nobody knew what the effects would be!!!!
With the safety systems turned off - the operators began the experiment with the
very unstable reactor and..... the rest is history.

A totally preventable accident - if only people would THINK about what they were
doing. However, in an oppressive society like the USSR - you did as you were told.

Dr. Gregory Greenman
Physicist
 
Last edited:
  • #24
396
2
Wow, my professor just covered Xe-135 poisoning this past week. Was there much known about poisoning at the time of the accident?
 
  • #25
Astronuc
Staff Emeritus
Science Advisor
19,843
3,329
theCandyman said:
Wow, my professor just covered Xe-135 poisoning this past week. Was there much known about poisoning at the time of the accident?
It has been well known for years before the Chernobyl accident since the 1950's. I believe it was Enrico Fermi who figured it out.

Here is a useful resource on nuclear power - http://book.nc.chalmers.se/KAPITEL/CH19NY3.PDF [Broken]
 
Last edited by a moderator:

Related Threads on Can a nuke power plant just blow up?

Replies
2
Views
3K
  • Last Post
2
Replies
30
Views
6K
  • Last Post
Replies
6
Views
9K
  • Last Post
Replies
4
Views
5K
Replies
7
Views
10K
Replies
8
Views
22K
  • Last Post
Replies
14
Views
5K
Replies
50
Views
18K
  • Last Post
2
Replies
25
Views
5K
Replies
4
Views
3K
Top