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PostPosted: Nov 23, 2014 12:04 pm 
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I didn't see a dedicated topic about security of Nuclear Power Plants against malveillant actions (if there is already one, I apologize) so let's begin one.

These last times nearly all of the french nuclear power plants (and the reprocessing plant of La Hague) have been overflyed repeatedly by mysterious drones whereas it is forbidden. It is very strange, we still don't know who control them. Some people here think there are maybe terrorists who prepare a vast attack, greater than the 9/11.

The containment building can not be damaged by a drone (or a bomb carried by a drone) but there are other parts of the plants which are more vulnerable, the spent fuel buildings for example, are not sufficiently protected say some people. There are also the diesel generators and the big spent fuel pools at La Hague. EDF and AREVA say that these buildings are sufficiently robust whereas some people say not.

They are maybe reconnaissance missions.

The transformers are also vulnerable. An expert say that if all the transformers are destroyed, France will be without electricity for a long time, bringing chaos.

Or they are just jokers ...

What do you think about it ?

For now the best thing is to destroy these drones and reinforce the security, it seems that the autorities will do that.

For the new designs of power plants I think that the spent fuel pool (or the separated fission products for LFTR ) must be inside a containment, below grade (with nothing below them except the steel liner and the concrete bedplate), protected by a shield building and passively cooled (so it would maybe be easier to put the spent fuel pool directly into the containment buiding of the reactor)

For the transformers and other sensible parts of the electrical grid I think we should have protected replacement parts of these systems for rapid repair of the grid.

For an eventual terrestrial terrorist attack I guess that there is already enough security.


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PostPosted: Nov 24, 2014 1:05 am 
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Nuclear power plants are good terror targets because the terrorists can both disrupt our daily lives by taking out the electricity, and by stealing nuclear material for dirty bombs.

The first can be dealt with by smart design of the electrical grid. I'm not necessarily talking about "the smart grid" that tell the utility when we're cooking supper or watching TV. Get distributed power, redundant systems where they make sense, and some other things. Bullet proofing transformers, as some politicians proposed after some yahoo shot some holes in a transformer in California, just sounds silly to me.

The second issue of terrorists trying to steal radioactive material can be dealt with by some properly designed reactors. Reactors like LFTR and DMSR that do not allow fissile material to build up in the fuel without also having some nasty isotopes in the mix to make the fuel salt worthless for bomb making.

I believe that natural disasters and our own government failures are greater threats to us than any terrorist.

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PostPosted: Nov 24, 2014 9:16 am 
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Really in any first world country the thought of terrorists being able to steal radioactive material from a plant is absurd.
They have ten minutes from breaching the wire to being buried under armed police and even every nearby military unit (and before anyone says Posse Comitatus in the US - the commander who took the call will likely happily resign afterwards).


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PostPosted: Nov 24, 2014 1:39 pm 
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It seems that the main threat is an attempt with big drones carrying a bomb crashing on the power plants.
The people say that the main targets are :

- destruction of the transformers or the electrical cables for a general blackout
- impact on the spent fuel building and the diesel generators for massive contamination

Some of the drones was 2 meters long. Nearly all of the power plants have been overflown several times.
The 31th october there have been 5 different Nuclear Power Plants overflown by a drone at the same night. That made us think that is a coordinate action with an organization behind it.

But a lot of people say also that they are not terrorists because they should have attacked a long time ago to take us by surprise. It is maybe some anti nuclear organization which try to demonstrate the vulnerability of the power plants and fool the autorities.


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PostPosted: Nov 24, 2014 4:07 pm 
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I think bombing a large number of big transformers at one time could make a lot of trouble. The ordering time for large transformers is quite long. Also, the production capacity is not large, because the demand is low. Most critical electricity users have back-up generators, but these are designed for outages of a few days, not many weeks on end.


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PostPosted: Nov 24, 2014 9:25 pm 
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The same would be the case with any number of other generators.

At least with an NPP the transformer is already inside a security cordon, not scattered to hell and gone across the countryside.


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PostPosted: Nov 25, 2014 3:38 am 
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NPPs require protection against storm produced missiles and such for the safety related equipment and support equipment. That includes the transformers for safety grade diesel generators.

If both main and aux (safety) transformers are outside in the open, that is bad design. It would not suprise me if some plants have actually done this wrong. Most nuclear regulators are too interested in codes and paperwork and "quality control" to focus on real safety issues. As made evident with Fukushima.


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PostPosted: Nov 25, 2014 1:51 pm 
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E Ireland wrote:
Really in any first world country the thought of terrorists being able to steal radioactive material from a plant is absurd.


I agree. Stealing radioactive material from an operating nuclear power plant is not some smash and grab job like someone stealing a fistful of diamond earrings. It is a lengthy process that requires great care or the people trying to steal the stuff will get such a heavy dose of radiation that they would not be able to walk off the property alive.

E Ireland wrote:
They have ten minutes from breaching the wire to being buried under armed police and even every nearby military unit (and before anyone says Posse Comitatus in the US - the commander who took the call will likely happily resign afterwards).


As one that believes strongly in the separation of powers and limited government I have no problem with military being called up to protect radioactive material from theft. Presumably the intent of stealing this material is not to feed and clothe the poor but to create a weapon. Such a weapon would only be of interest to people that wish to engage in war or rebellion. As it turns out the Posse Comitatus Act has an exception in the law for calling up the military for the prevention of the spread of nuclear materials.

Even with the great hazards that one would have to overcome (radiation poisoning from the material or "lead poisoning" from government agents) to steal nuclear material or damage a nuclear power plant I still feel that we can do much more with minimal cost to deter such acts. To make the cost manageable these deterrents must be considered at the time of construction, trying to bolt them on afterward can make costs soar.

I feel that there is a much greater threat in the spent fuel from nuclear power plants. The highly radioactive isotopes will decay off in perhaps decades. The "poison" isotopes that make the plutonium in the fuel rods undesirable have a shorter half life than the stuff someone could use in a weapon. That means to me that at some point in the future these fuel rods will contain weapon grade plutonium. That time frame may be hundreds of years but nuclear waste sites like Yucca Mountain intend to store this stuff away for thousands of years. That means some future generation will have to be concerned about the weapon potential this stuff poses.

If we are going to concern ourselves with the legacy we leave for the future in nuclear hazards then we need to find a way to burn up these spent fuel rods rather than store them away and allow them to effectively enrich themselves into weapons grade material.

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PostPosted: Nov 25, 2014 4:33 pm 
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Quote:
there are other parts of the plants which are more vulnerable, the spent fuel buildings for example, are not sufficiently protected say some people.


Some people... don't understand the stopping power of 8 meters of water. In some ways water is a better events shield than concrete since it self seals up again any hole.

Even if the spent fuel pool is in a flimsy building you get all that water on top of the spent fuel. Even if you could damage the spent fuel that is not enough to cause a large release because the water absorbs all the fission products.

For this to be a serious accident a terrorist would have to penetrate 8 meters of water, then damage a big portion of the spent fuel (how has he done this with a thin penetrator that can pierce the water?) and it has to punch a hole in the 2+ meter thick reinforced concrete spent fuel pool itself. That hole also must be big enough for the many makeup systems to be unable to keep up, or the makeup systems have to be sabotaged and mobile makeup systems somehow thwarted.

Its all so far fetched. The only way to effectively do this is to use a bunker buster (which terrorists don't have) combined with elaborate sabotage of emergency makeup equipment.

A nuclear powerplant is not an attractive terrorist target. It is a very hard industrial target with no one living next to it. Exactly the opposite of what terrorists would be looking for, they want soft targets with lots of people in it and nearby.


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PostPosted: Nov 25, 2014 6:07 pm 
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Cyril R wrote:
they want soft targets with lots of people in it and nearby.


I agree. Perhaps, for an example, lines and lines of people crowded outside a TSA checkpoint at an airport on the day after Thanksgiving?

I know that my comment is leaning off topic but things like this come to mind at this time of year.

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PostPosted: Nov 25, 2014 7:28 pm 
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Kurt Sellner wrote:
Even with the great hazards that one would have to overcome (radiation poisoning from the material or "lead poisoning" from government agents) to steal nuclear material or damage a nuclear power plant I still feel that we can do much more with minimal cost to deter such acts. To make the cost manageable these deterrents must be considered at the time of construction, trying to bolt them on afterward can make costs soar.

I feel that there is a much greater threat in the spent fuel from nuclear power plants. The highly radioactive isotopes will decay off in perhaps decades. The "poison" isotopes that make the plutonium in the fuel rods undesirable have a shorter half life than the stuff someone could use in a weapon. That means to me that at some point in the future these fuel rods will contain weapon grade plutonium. That time frame may be hundreds of years but nuclear waste sites like Yucca Mountain intend to store this stuff away for thousands of years. That means some future generation will have to be concerned about the weapon potential this stuff poses.

The NRC is already fully paranoid in nuclear safety matters. Unless you are directly involved with the nuclear security process, I doubt you can contribute to make the process safer, as you don't know all the safety contingencies. If I learned anything 100% clear in the 3 years I've been reading about nuclear power is that the NRC doesn't care about costs, they are dedicated to making the nuclear industry as expensive as possible by going full crazy on nuclear over regulation.

Reactor grade plutonium is next to useless for nuclear weapons making. Much easier to just enrich Uranium and make a U-235 bomb. Making a nuclear weapon with reactor grade plutonium is very dangerous unless its going to be used immediately. High risk of premature detonation. High risk of duds.
That's one more point in for MSR reactors. They could continuously recycle the fuel, leading to a very high Pu-242 content, which would make that plutonium 100% useless for bomb making. Need a high minimum level of Pu-239 in order to get a nuclear detonation at all.

When we'll we understand that ?

We should be moving away from once through fueling. Once we do reprocessing, we could recycle 100% of the Plutonium, Neptunium and Uranium on current water cooled reactors. With MSRs we could recycle 100% of fissile and fertile (assuming a stockpile of Plutonium to increase fissile ratio) and Fast Reactors once started up only need fertile material, and can take in as much SNF as available.

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PostPosted: Nov 25, 2014 9:42 pm 
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The only danger from terrorists to nuclear power in the US I can see would be to try to cause a situation similar to Fukushima at some plant that needs an upgrade. I don't think we have any of those.

Clearly, the transmission lines are vulnerable so one could easily imagine an attack to take out key transmission lines and power substations and try to cause cascading failures. The nuclear power portion of our society is probably amongst the most robust against attack.


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PostPosted: Nov 25, 2014 10:25 pm 
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macpacheco wrote:
The NRC is already fully paranoid in nuclear safety matters.


I agree. The NRC is so afraid of something going wrong that they don't want to try anything new. This status quo means that nothing "unsafe" can be done, or that any current policy or practice that can be proven unsafe will be ended.

macpacheco wrote:
Reactor grade plutonium is next to useless for nuclear weapons making.


I understand that. What I was pointing out is that the "bad" plutonium isotopes have a shorter half life than that of the "good" isotopes. That means that the spent fuel rods that are piling up instead of being recycled are slowly turning from reactor grade plutonium into weapons grade plutonium. Just one example of how bad policy does not go away.

I also understand that the self enrichment of decaying plutonium is a process that can take hundreds or even thousands of years. What government policy is now is to take the spent fuel from reactors and put it in a hole for hundreds or thousands of years, instead of recycling it. That means some future society can dig up this weapons grade plutonium. At the current pace of government change on nuclear material policy that plutonium in the SNF could actually decay into weapons grade before the policy on recycling it changes.

This government policy that is supposed to deter proliferation of nuclear weapons is actually making the problem worse. They are allowing plutonium to pile up instead of destroying it. The bonus to destroying the plutonium and getting rid of the problem is that lots of energy can be made in the process.

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Disclaimer: I am an engineer but not a nuclear engineer, mechanical engineer, chemical engineer, or industrial engineer. My education included electrical, computer, and software engineering.


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PostPosted: Nov 27, 2014 12:12 pm 
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There are projections that reactor grade plutonium can be used to build subkiloton nuclear weapons that have a high degree of reliability - but those are not the type of weapons a terrorist group is likely to be able to manufacture in the near future.


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PostPosted: Nov 29, 2014 3:49 pm 
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Kurt Sellner wrote:
I understand that. What I was pointing out is that the "bad" plutonium isotopes have a shorter half life than that of the "good" isotopes. That means that the spent fuel rods that are piling up instead of being recycled are slowly turning from reactor grade plutonium into weapons grade plutonium.
Waiting for higher isotopes to decay is not a practical way to get your bomb grade Plutonium. Half lives of Pu 240 = 6,564 years. Pu 241 = 14.35 years. Pu 242 = 373,310 years. Pu 243 = 4.9 hours. Pu 244 = 80.8 million years.

Any thing smaller than a State sized effort to make a reliable fission weapon from reactor grade Plutonium would be futile, and even they may not be succeed.

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