Nuclear power in US - safety against unforeseen situations.

AI Thread Summary
The discussion centers on the preparedness of U.S. nuclear power plants in the event of an accident, comparing them to the Fukushima incident. Questions are raised about the availability of equipment similar to Japan's KHG robots and whether U.S. reactors have sufficient emergency response capabilities, such as quickly delivering generators and other critical systems via heavy-lift helicopters. The feasibility of transporting heavy equipment by air is debated, with concerns about the weight limits of available helicopters and the design choices of nuclear facilities, which typically do not include helicopter pads. The conversation also highlights the need for better risk assessment and planning for unforeseen circumstances, emphasizing that current reactor designs incorporate more passive safety features than those used in Japan. Overall, the dialogue underscores the importance of evaluating and improving emergency response strategies for nuclear power plants.
Dmytry
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A couple questions.
1: Does US have anything similar to KHG? US robots on site in Fukushima - one with digital radiation monitor, other looking at first through camera - is that what US would use at US reactor accident? Is there a shortage / unavailability of such equipment for US-built reactors aboard?
2: Can the generators and substitute electrical equipment be quickly delivered on site by heavy transport helicopter in the event of failure of electrical systems like Fukushima (and successfully connected) ? Ditto for fuel and water. Ditto for pumps. So that all the critical safety equipment can be replaced with portable substitute. I know that German equipment is standardized and common industrial generators working at common voltages can be used to power cooling pumps. From Fukushima I know that they could not do this.
3: Why nuclear power plants don't have helicopter pads on the roofs just in case?
 
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3: Why nuclear power plants don't have helicopter pads on the roofs just in case?

In case of what? Wouldn't it be better to have it in an open field nearby? Otherwise you run into the problem of unloading heavy equipment from a rooftop and other things.
 
Oh, also I do know that current reactor designs are much different than the ones in Japan. I believe that there are many more passive safety features that should prevent much of what happened in japan. (In your words this would be "Generic" safety features.)
 
Do you have any answers? I am asking specific questions. So far I take your answer as "No and I don't think anything like that is necessary".
For helicopter pad - auxiliary in the event that there's mess on the ground.
 
Dmytry said:
2: Can the generators and substitute electrical equipment be quickly delivered on site by heavy transport helicopter in the event of failure of electrical systems like Fukushima (and successfully connected) ? Ditto for fuel and water. Ditto for pumps. So that all the critical safety equipment can be replaced with portable substitute. I know that German equipment is standardized and common industrial generators working at common voltages can be used to power cooling pumps. From Fukushima I know that they could not do this.
Weight (mass) of that equipment? How it corresponds to load-carrying capacity of the heavy-lift helicopters available in the market (Mi-26, Chinook, Stallion)? On Fukushima we see that those equipments have been installed after a few days after accident. Is this option so critical for total safety level of power plant?
Dmytry said:
3: Why nuclear power plants don't have helicopter pads on the roofs just in case?
The simple answer to this question - builders build according to the approved design. And in that design the helicopter pad on a roof does not provided.
 
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Joseph Chikva said:
Weight (mass) of that equipment? How it corresponds to load-carrying capacity of the heavy-lift helicopters available in the market (Mi-26, Chinook, Stallion)?
I am asking the question, whenever there is such capability? Until i get 'no' i am not asking why there isn't.
On Fukushima we see that those equipments have been installed after a few days after accident.
Ohh right and then they couldn't power even the spent fuel pool pumps. Meaning the did not have this capability.
Is this option so critical for total safety level of power plant?
I'm curious if engineers think that it is so critical. I'll myself think whenever it looks more like they're planning for 1 in 100 or 1 in 10 000 lifetime risk of failure.
The simple answer to this question - builders build according to the approved design. And in that design the helicopter pad on a roof does not provided.
switchgear in basement however is provided.
 
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I think (sure) that most of that equipment is heavier than any helicopter able to lift.
I asked you about their weights - you maintained Germany origin equipment.

Many kinds of options may be suggested for prompt response. But I think that decision making time much longer than transportation time by helicopters. So, no advantage.
 
Well, the cooling power requirements I (and you) can easily calculate, and then I can look up its weight.
http://en.wikipedia.org/wiki/File:Decay_heat_illustration2.PNG
60 minutes in, you have, let's say, <1.5% , which for 3GW thermal is 45 MW thermal.
http://www.wolframalpha.com/input/?i=75+bar+*+(45+MW+/+water+heat+of+vaporization)/water+density
150kw mechanical power to pump & cool by water boiling off, 750kw electrical should be plenty.
http://cfaspower.com/GTG_1366_Saturn_Mob.doc
7.5 tons for 750kw.
Big transport chopper lifts few tens tons.
Calculating fuel requirements and water requirements is left as exercise for the reader.

Decision making time: got to pre-decide what to do in event of cooling power failure.
 
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Dmytry said:
Decision making time: got to pre-decide what to do in event of cooling power failure.
But also situation should be monitored before, then - decide what to do. It requires much more time than needed for example to trucks.

If 7.5 tons yes - it easily can be transported by heavy-lift helicopters.

But which helicopter can carry a few tens tons?
 
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  • #10
Joseph Chikva said:
But also situation should be monitored before, then - decide what to do. It requires much more time than needed for example to trucks.
You can't bring up pump power (not exactly difficult to monitor) - you look in SAMG - it says to call for external equipment - you do that. It's safety, man, you don't need to be so sceptical about worst cases, you don't need to wait for definite proof external equipment is necessary.
Versus assembling meeting of the top executives etc.
If 7.5 tons yes - it easily can be transported by heavy-lift helicopters.

But which helicopter can carry a few tens tons?
Mi-26 for example.
Natural disaster may damage road.
 
  • #11
Dmytry said:
You can't bring up pump power (not exactly difficult to monitor) - you look in SAMG - it says to call for external equipment - you do that. It's safety, man, you don't need to be so sceptical about worst cases, you don't need to wait for definite proof external equipment is necessary.
Versus assembling meeting of the top executives etc.

Mi-26 for example.
Natural disaster may damage road.
  • Mi-26 can carry only two tens tons. And it is a big question undersling or in cabin.
  • Super Stallion - up to 15
  • Chinook - about 10
But when we have a task of carrying of big load, usage of Chinook is preferable thanks to its design - no main+tail rotors, but two main rotors. This design is less critical how far is the center of mass of load from helicopter's lift center.
 
  • #12
How much it can carry depends to how much fuel it needs. Didn't really realize Mi-26 was so much bigger than all other alternatives (28 ton load+fuel)
In any case, a few choppers can deliver everything necessary for an accident that disabled power plant's electrical system and keep delivering the fuel (delivering the water might be problematic but a reactor ought to have a lot of spare water). The reactors cost multiple billion dollars each, right? And you need only a few such things for many reactors + the helicopters could be provided by military.
Furthermore, the reactor shouldn't really be kept at 75 bar operating pressure during emergency shut-down, right? Make it 7.5 bar and power requirements are 10x less.

Really, I think the biggest problem is the underestimate of risk of unforeseen circumstances. Tsunami is unlikely, terrorist attack is unlikely, sabotage is unlikely, etc etc but this stuff adds up and there's response that can be effective in the multitude of unforeseen circumstances - general ability to replace critical systems. Scepticism is good, but not extreme scepticism when evaluating possible disaster scenarios - instead one has to be sceptical of ability to predict.

edit: also, what is power/weight ratio of air coolers?
So far i can only find rates for small stuff:
http://www.megawavz.com/product.aspx?id=349572&desc=Price_SDVC5000_HVAC_Radiator
700L/s with weight of 32 lbs = 15kg.
the heat capacity of air at standard conditions is about 1.0 kJ/kg K (more at high temperatures), let's suppose we heat air up by 50 celsius, and let's suppose 1 litre of air weights 1.2 grams, 700 *0.0012 = 0.84 kg/s , 42KW cooling for weight of 15kg, so 15 tons for 40MW . 7.5 tons if we heat air up by 100 celsius.
I'd think larger unit would have better dissipation power / weight ratio.
I was really surprised this waste heat was such a big problem. 45MW is not a lot.
 
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  • #13
Dmytry said:
How much it can carry depends to how much fuel it needs. Didn't really realize Mi-26 was so much bigger than all other alternatives (28 ton load+fuel)
In any case, a few choppers can deliver everything necessary for an accident that disabled power plant's electrical system and keep delivering the fuel (delivering the water might be problematic but a reactor ought to have a lot of spare water). The reactors cost multiple billion dollars each, right? And you need only a few such things for many reactors + the helicopters could be provided by military.
Furthermore, the reactor shouldn't really be kept at 75 bar operating pressure during emergency shut-down, right? Make it 7.5 bar and power requirements are 10x less.

Really, I think the biggest problem is the underestimate of risk of unforeseen circumstances. Tsunami is unlikely, terrorist attack is unlikely, sabotage is unlikely, etc etc but this stuff adds up and there's response that can be effective in the multitude of unforeseen circumstances - general ability to replace critical systems. Scepticism is good, but not extreme scepticism when evaluating possible disaster scenarios - instead one has to be sceptical of ability to predict.
Dmytry,
It is easy to calculate 20 tons or 28 tons when you see technical data of device or a few tens tons before seeing.
The problem is not in how we can search and find information or how we can add two numbers. I am a little bit familiar with helicopters and never heard about 28 tons load - minus some fuel. May be carrying of so big load for helicopters is bigger challenge?
And yes, may be disaster damage road. But why not landing near power plant. Why obligatory on the top?
 
  • #14
Not obligatory landing on the roof. A minor safety feature for circumstances that preclude landing on the ground. Not very important, an proxy for safety conscious design.

The point is, this core cooling system loss - the power requirements are laughable. 45 megawatts, and they can't dissipate it with RCIC and some air cooled condenser, like, big HVAC. What the hell. Everywhere I look at nuclear industry, I see something similar to those 2 robots, one with consumer grade radiation monitor (by the look of it, no recording capability lol), other to take readings.
 
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  • #15
Dmytry said:
A couple questions.
1: Does US have anything similar to KHG? US robots on site in Fukushima - one with digital radiation monitor, other looking at first through camera - is that what US would use at US reactor accident? Is there a shortage / unavailability of such equipment for US-built reactors aboard?
2: Can the generators and substitute electrical equipment be quickly delivered on site by heavy transport helicopter in the event of failure of electrical systems like Fukushima (and successfully connected) ? Ditto for fuel and water. Ditto for pumps. So that all the critical safety equipment can be replaced with portable substitute. I know that German equipment is standardized and common industrial generators working at common voltages can be used to power cooling pumps. From Fukushima I know that they could not do this.
3: Why nuclear power plants don't have helicopter pads on the roofs just in case?

1. Yes - the US had robots since the early 1980's. Some are used routinely for inspection of irradiated areas, e.g., steam generators and the primary system.

http://www.iaea.org/Publications/Magazines/Bulletin/Bull273/27304393138.pdf (1985)

http://web.eecs.utk.edu/~parker/publications/Handbook99.pdf (1999)

EPRI has supported many remote inspection and service technologies on behalf of the nuclear industry, and the technology suppliers have developed their own proprietary systems. Some utilities have developed their own systems.

The US does enjoy a common AC frequency nationwide.

Heavy equipment can be brought to any NPP site in the US.

Based on Fukushima, utilities have been reviewing their plant designs for potential vulnerabilities, and their EOPs and SAMGs (severe accident mitigation guidelines).
 
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  • #16
Astronuc said:
1. Yes - the US had robots since the early 1980's. Some are used routinely for inspection of irradiated areas, e.g., steam generators and the primary system.

http://www.iaea.org/Publications/Magazines/Bulletin/Bull273/27304393138.pdf (1985)

EPRI has supported many remote inspection and service technologies on behalf of the nuclear industry, and the technology suppliers have developed their own proprietary systems. Some utilities have developed their own systems.
Good. Then WTF Japanese are doing with those two ibots?
The US does enjoy a common AC frequency nationwide.

Heavy equipment can be brought to any NPP site in the US.
But for that there needs to be a plan... the voltages must match, connectors, etc, the equipment must be ready for delivery.
Based on Fukushima, utilities have been reviewing their plant designs for potential vulnerabilities, and their EOPs and SAMGs (severe accident mitigation guidelines).
Well that's good to know. Pro nuclear people here (certain nuclear engineers supposedly) have almost got me convinced they see no need for ability to replace critical systems in the event of unforeseen circumstances, and argue against it.
 
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  • #17
Dmytry said:
Not obligatory landing on the roof. A minor safety feature for circumstances that preclude landing on the ground. Not very important, an proxy for safety conscious design.

The point is, this core cooling system loss - the power requirements are laughable. 45 megawatts, and they can't dissipate it with RCIC and some air cooled condenser, like, big HVAC. What the hell. Everywhere I look at nuclear industry, I see something similar to those 2 robots, one with consumer grade radiation monitor (by the look of it, no recording capability lol), other to take readings.
I am afraid that information is dosed and consequently it does not correct absolutely to speak about "laughable" requirements.
Regarding offered by you helicopters pad I stay at the same - they won't add more safety.
Certainly, if you Dmytry is customer company and I – the company-contractor, on request for monitoring underwater environment I will provide you though a pocket submarine.
 
  • #18
See, they have 3000MW dissipating equipment that was reduced to scrap metal because they did not have 45MW dissipating equipment. Think a little. UTTER ABSURD just like 2 robots one with radiation monitor other to look at it (unable to see through steam).
 
  • #19
Dmytry said:
See, they have 3000MW dissipating equipment that was reduced to scrap metal because they did not have 45MW dissipating equipment. Think a little. UTTER ABSURD just like 2 robots one with radiation monitor other to look at it (unable to see through steam).
I wouldn’t like to offend you. But everyone thinks himself as great strategist seeing the fight from outside.
 
  • #20
See, I was asking specific questions here. Instead i get arguments like it being too heavy for #2 (ain't true) , the #3 being useless (ain't going to bother to argue), what ever, rationalizing lack of 1,2,3 even before absence is confirmed. That's the typical pro-nuclear behaviour.
Decay heat is nearly trivial (for a system of such operational power, I mean). Can be handled with very simple passive systems (ABWR and simplified BWR). Instead, in old reactors, relies entirely on electrical equipment that can sometimes be found in basement, never upgraded for passive cooling, no indication of well defined plans for response to failure, etc, a lot of apologism for that as well.

Someone asks about reactor uprating, they get told of turbine improvements etc etc, which aren't nuclear, an attempt is made to make it look as if reactor thermal power output uprating by ~7 percent was not common. Typical.
You know, you guys are actually far more effective than greenpeace at showing nuclear industry as unsafe.
 
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  • #21
Dmytry said:
You know, you guys are actually far more effective than greenpeace at showing nuclear industry as unsafe.
From my side I have never said about nuclear power safety but at the same time I say that it has not any alternative. Frankly I was bothered to repeat the same in various variations. Greenpeace can jump up and down but everyone from that respectful organization uses the civilization blessings. This impossible without energy.
Regarding safety level.
It can not be infinitely high but should be reasonably high. As it connected with infinitely high expenses. And every project has limited budget. That's all.
Thanks.
 
  • #22
The safety level can also be just as high as necessary to 'probably' (p<0.5) not suffer an accident in either of a hundred reactors of a particular design during the career of a person in charge of design. If you want nuclear power to have future - you'd better try and convince that the process ensures higher safety than this 'reasonably high' when http://en.wikipedia.org/wiki/Homo_economicus" in charge of the project is doing the reasoning for what safety is best for his own private benefit.
As a null hypothesis, I assume that the safety is in the ballpark of the optimum for people in charge / owners. That is, lifetime risk of severe accident on order of 1/100 .. 1/500 . I'm very curious what rates insurance companies charge nuclear reactor operators.
 
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  • #23
PRA Risk is usually greater then 1/100,000 reactor operating years. When approaching less the 1/10,000, operators will establish added boundaries to protect the site or shut down.

I believe insurance costs are typically 1 to 2 million a year per unit depending on the site. Contact them for more info:

http://www.nmlneil.com/
 
  • #24
i've used NRC figures:
http://www.nrc.gov/reading-rm/doc-collections/fact-sheets/funds-fs.html
says 400K/year paid for single unit reactor site, covering 375M liability , giving a risk of >=375M accident on order of 1/1000 reactor years.
That is the estimate by companies that put their money on the table. I'm pretty sure someone would price cut if they thought the risk was 1/10 000. The risks - the problem is - suppose you analyse the plant, and you see risk of 1/50 000 by combining risks from various scenarios . What is the risk that you overseen some issue? Isn't it helluva lot bigger? Whats about all the potential issues you can't think up, which each is extremely low risk, but they all add up?
 
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  • #25
Note that it says 400k average. If your plant is in the middle of nowhere like Cooper in Nebraska I'm sure it is cheaper then somewhere like Indian Point right outside of New York City or San Onofre outside of LA/Orange County.

The risk I was referring to was the PRA risk which calculates Core Damage Frequency and Large Early Release probabilities. Essentially the probability if a major accident were to occur, what is the probability the core will melt of containment will be compromised and release radionuclides to the atmosphere. Maybe the risk that insurance companies define is broader in damage and account for any accident (ie fire, flooding, etc)
 
  • #26
traijan said:
Note that it says 400k average. If your plant is in the middle of nowhere like Cooper in Nebraska I'm sure it is cheaper then somewhere like Indian Point right outside of New York City or San Onofre outside of LA/Orange County.

The risk I was referring to was the PRA risk which calculates Core Damage Frequency and Large Early Release probabilities. Essentially the probability if a major accident were to occur, what is the probability the core will melt of containment will be compromised and release radionuclides to the atmosphere. Maybe the risk that insurance companies define is broader in damage and account for any accident (ie fire, flooding, etc)
Well, its for liabilities... so it includes anything that nuclear power plant can be found liable for. Which is, incidentally, what I care about if I live next to plant. I don't really care if it just blows up on it's own, or it blows up due to flood. If anything, if i could trade it blowing up by itself for it blowing up during a disaster - i'd rather it blows up by itself, better to deal with nuclear accident alone than it superimposed onto tsunami, don't you think?

Really, the nuclear power plant accidents seem to be all or nothing affairs very much. Either almost no release, or a giant release. No level 6, two level 7.
 
  • #27
Not according to the accident event sheet
http://www.iaea.org/Publications/Factsheets/English/ines.pdf .

And two major accidents in how many operating years worldwide with all the plants that have been online? Take the sum total of all the hours operating at full power. Compare this to all the oil refinery and chemical plant explosions, spills, releases, etc. And not to mention Coal fire plant pollution discharges, fires, acid rain, etc. Also, mind you that Nuke Plants are required to strictly monitor all effluent discharges for radiation, unlike coal plants that spew out large amounts of unmonitored radioactive releases and mercury and sulphur into the air.

http://www.scientificamerican.com/article.cfm?id=coal-ash-is-more-radioactive-than-nuclear-waste

I think in the end, if you want a stable grid with little emissions or environmental impact Nuke are still the safest and cleanest. All energy generation options have their tradeoffs and the goal is to mitigate and control these tradeoffs.
 
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  • #28
Do you have any answers? I am asking specific questions.

I gave you answers. If you don't like them, too bad.

For helicopter pad - auxiliary in the event that there's mess on the ground.

An auxillary pad in case there's a mess on the ground? I see where you would think this would be a good idea, but I don't think there would be any real benefit. If there is a mess on the ground then I see it as unlikely that it would be easier to unload heavy equipment from a rooftop.

So far I take your answer as "No and I don't think anything like that is necessary

That's because I don't see any benefit to your suggestions. I think about it, I compare the suggested use of it against the situations where it would be required, and usually I can think of several reasons why it actually isn't a very good idea to me. Like I said, if you are building auxillary helipads on top of bulidings just in case something on the ground happens, then would it actually be useful in an event like that? I don't think so. Why? Because of difficulties and complexities in loading/unloading equipment from the top of a building and because if the situation on the ground is so bad that you can't land a helicopter I don't see anyone getting any heavy equipment in there at all. Because of that I don't think it's a good idea to build it, not even to build it "Just in case". That's not the way safety works. You don't build random stuff just in case something might happen. You evaluate the possibilities, come up with REASONABLE solutions to those possibilities, and then design your safety off of that. I say reasonable in the sense that it isn't going to bankrupt your company to do these things. That very well might include building an auxillary generator building, or ensuring multiple backups of critical systems, or whatever. But none of those are built just in case something goes wrong. They are built for specific purposes in mind to protect against. I hope you don't misinterpret this as me saying I don't care about safety. Nothing could be further from the truth. What I don't care about is pointless excessive safety that impedes work or runs up costs without a valid reason.
 
  • #29
According to WNN - Both units at the Surry nuclear plant in Virginia shut down automatically as designed when a tornado touched down at the plant's switchyard, cutting off external electricity connection. Backup diesel generators started up immediately to provide the necessary power to keep the two pressurised water reactors in a safe and stable condition. Off-site power was subsequently restored.

Both units are still down pending repairs to equipment.

A tornado (high wind) is one of the natural phenomena that plant designs must concern, even if it is a low probability event.

When hurricane approaches the east coast, plants will go to hot zero power or hot standby, just in case they loose off-site power connection.
 
  • #30
Dmytry said:
Someone asks about reactor uprating, they get told of turbine improvements etc etc, which aren't nuclear, an attempt is made to make it look as if reactor thermal power output uprating by ~7 percent was not common. Typical.
You know, you guys are actually far more effective than greenpeace at showing nuclear industry as unsafe.
No attempt was made here to "make it look as if reactor thermal power output uprating by ~7 percent was not common".

The low power density units can increase power by up to 20%, and some operated on 24 month cycles. The highest power density units are generally limited to about 7% uprate, and they remain on 18 month cycles. I know of one plant that increased the core power by 5%, but then optimized the core design to reduce power peaking, to the peak local powers and burnups are actually less than when they operated at lower power.
 
  • #31
Astronuc said:
No attempt was made here to "make it look as if reactor thermal power output uprating by ~7 percent was not common".

The low power density units can increase power by up to 20%, and some operated on 24 month cycles. The highest power density units are generally limited to about 7% uprate, and they remain on 18 month cycles. I know of one plant that increased the core power by 5%, but then optimized the core design to reduce power peaking, to the peak local powers and burnups are actually less than when they operated at lower power.

Well there was a definite attempt at shift of topic from the reactor uprating to turbine upgrading etc, and to fraction of a percent uprating due to better measurement.

There was also NUCENG who from earlier discussion of role of CsI in the transport of Cs-137 along with I-131, I have assumed was some sort of bystander with no clue how to relate Becquerel to number of atoms and half life (even if it is 10X the Iodine to Caesium in Bq, it is 1/136 or so the Iodine to Caesium in number of atoms coz I-131 has half life 8 days and Cs-137 has half life 30 years). Which would of been totally fine if he was. I don't mind explaining Bq to people outside nuclear industry and how it relates to half life and number of atoms. I don't think everyone has to know how decay works. Then it turns out he's in fact (or claims to be) a nuclear engineer with many years of experience, involved in uprating, and goes on with his ultra arrogant attitude that he knows enough and has nothing to learn. Right, precisely the kind of person I'd trust with uprating.
Really, this forum is such an eye opener.
 
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  • #32
Dmytry said:
Well there was a definite attempt at shift of topic from the reactor uprating to turbine upgrading etc, and to fraction of a percent uprating due to better measurement.
No such attempt. One is simply being dishonest.

There was also NUCENG who from earlier discussion of role of CsI in the transport of Cs-137 along with I-131, I have assumed was some sort of bystander with no clue how to relate Becquerel to number of atoms and half life (even if it is 10X the Iodine to Caesium in Bq, it is 1/136 or so the Iodine to Caesium in number of atoms coz I-131 has half life 8 days and Cs-137 has half life 30 years). Which would of been totally fine if he was. I don't mind explaining Bq to people outside nuclear industry and how it relates to half life and number of atoms. I don't think everyone has to know how decay works. Then it turns out he's in fact (or claims to be) a nuclear engineer with many years of experience, involved in uprating, and goes on with his ultra arrogant attitude that he knows enough and has nothing to learn. Right, precisely the kind of person I'd trust with uprating.
Really, this forum is such an eye opener.
NUCENG made it quite clear about his experience. There is no arrogant attitude, just a preference for honest criticism.
 
  • #33
Dmytry said:
Well there was a definite attempt at shift of topic from the reactor uprating to turbine upgrading etc, and to fraction of a percent uprating due to better measurement.

I must have missed that, can you link to the post where that discussion took place?
 
  • #34
Astronuc said:
No attempt was made here to "make it look as if reactor thermal power output uprating by ~7 percent was not common".

The low power density units can increase power by up to 20%, and some operated on 24 month cycles. The highest power density units are generally limited to about 7% uprate, and they remain on 18 month cycles. I know of one plant that increased the core power by 5%, but then optimized the core design to reduce power peaking, to the peak local powers and burnups are actually less than when they operated at lower power.

Astronuc said:
No such attempt. One is simply being dishonest.
Ok I guess we'd have to disagree on this one, you think that bringing up turbine/transformer/etc upgrading is very relevant to safety of reactor uprating does not constitute attempt to switch the topic, fine. In my eyes it does.
NUCENG made it quite clear about his experience. There is no arrogant attitude, just a preference for honest criticism.
Well, what ever. I guess i'd be flamed for arrogance for assuming that I, without any experience, believe that I know how to convert from Bq/ml to molar concentration. edit: tp clarify, when it comes to discussing compounds like CsI .
 
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  • #35
gmax137 said:
I must have missed that, can you link to the post where that discussion took place?
https://www.physicsforums.com/showthread.php?t=491464
coverage of the turbine improvements, more accurate measurements (fraction of percent), etc. Well, OK enough, they didn't really try a lot to shift the topic away from reactor core power increase compared to typical news pieces. Half of my pissed-off-ness is at NRC page about it, press, etc with their shift of focus and always mixing in / emphasising non-reactor improvements. Got to give credit to guys here that they don't very much want to shift the focus, perhaps only to explain that the increases in power are not totally from the core uprating. Ok, I retract the argument on the turbine improvements etc. Point still holds that in the event of meltdown, obviously more fuel is worse thing (ditto for more fuel that was irradiated for more months at higher neutron flux). More decay heat.

Whenever that increases the risk a lot - dunno, IMO the risk is the risk of human mistake when designing the uprate, and the risk of corruption (given the money involved). Technologically yea I' agree you can uprate safely, in theory.
 
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  • #36
Whenever that increases the risk a lot - dunno, IMO the risk is the risk of human mistake when designing the uprate, and the risk of corruption (given the money involved). Technologically yea I' agree you can uprate safely, in theory.

So you have no problem with the technical aspects of uprating, but you don't think that 100+ people can safely design a reactor? Even though it happens all the time?
 
  • #37
still no definite answers from those in the industry about 1 or 2.

Drakkith said:
So you have no problem with the technical aspects of uprating, but you don't think that 100+ people can safely design a reactor? Even though it happens all the time?
lol.
100+ people can do a lot of things. They can design a reactor safely, or they can rationalize away unsafe changes as not degrading safety, and make very convincing arguments for that. There's the risk of a group of people doing the latter rather than the former.

Consider those re-racked pools. Originally, racked with enough space between the plates so that no neutron absorbers are needed. Later on re-racked for higher density with boral plates, which if they fail, the stuff can go critical. The boral plates do not even behave as originally intended (water seeps in and reacts with aluminium, bulging the plates to the point of fuel assemblies getting stuck).
http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr0933/sec3/196.html
The unintended is then declared to be insignificant. Right.

Now we have Fukushima and we think how did the reactor building 4 explode so bad, and this higher fuel density and boral add a lot of new nasty possibilities. Re-racking may not increase the risk of loss of water in spent fuel pool, but it definitely makes consequences of such loss a lot worse and/or makes them happen earlier. Now, suppose you assume lifetime risk of loss of water is 1/100 000, then the extra risks, they are negligible, it is just the things that happen when you lose water in SPF and a-priori less than 1/100 000 chance that happens. Why, you can add a backup here, a small backup there, decrease loss of risk of water somewhat, and maintain same safety!
Then, suppose the risk of loss of water is somewhere closer to 1/100 - 1/500 due to natural disasters etc (historical, see Fukushima), the stuff that is not part of 1/100 000 figure. Those extra risks are then no longer so negligible, and not easily compensated for.

You see, there's the thing. Nuclear energy is more expensive than coal and gas. It's not some stuff that really got lot of spare money for safety. It's stuff that's barely commercially viable, or not commercially viable, versus fossil fuels. (Yes I do not like fossil fuels either but they exist, and they are going to be all burnt up unless nuclear is *cheaper* than fossil). On top of that, the safety/cost tradeoff that is optimal for power company + farmers, fishermen, etc. is dramatically different from that optimal for the company alone. Company faces a lot of extra financial risk from every safety feature that costs money. It is really easy to get a mindset where you don't add any extras unless it is absolutely, positively proven that you need them. And it is easy to adopt a structure whereby 100+ people would be more trying to disprove need for safety systems - trying to improve the revenue - rather than try to, essentially, find new risks that require protection, and raise the costs of operation and cause financial damage to their employer.

Read this regarding safety:
http://www.fotuva.org/feynman/challenger-appendix.html
Space shuttle. Risk according to management = 1/100 000 . Historical risk = somewhere around 1/60 . Probability that management is right and it was just bad luck = less than 1/1000
 
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  • #38
Astronuc said:
No such attempt. One is simply being dishonest.

NUCENG made it quite clear about his experience. There is no arrogant attitude, just a preference for honest criticism.

Astronuc,
Thank you for trying to defend me to Dmytry, however, it is not necessary. People reading this forum must make their own judgement about my credibility. I did make an error in computation of Bq/cm3 in the Spent Fuel Pool of unit 4. Two readers checked my results and came up with a different result. I thanked them for checking my work and admitted my mistake. So much for arrogance. An engineer unwilling to make a mistake is not able to do anything worthwhile.

I have chosen to ignore Dmytry because I tired of him twisting my words, and reading things into my posts that he alone seems to see. I will keep reading these forums. Should he choose to treat my opions with the respect I offer his, I will even rejoin discussion with him. If everyone agreed with me, I wouldn't have to say anything. When there is disagreement, the need is for communication. Questioning the intelligence, honesty or motives of those who disagree with you isn't communication.
 
  • #39
NUCENG said:
Astronuc,
Thank you for trying to defend me to Dmytry, however, it is not necessary. People reading this forum must make their own judgement about my credibility. I did make an error in computation of Bq/cm3 in the Spent Fuel Pool of unit 4. Two readers checked my results and came up with a different result. I thanked them for checking my work and admitted my mistake. So much for arrogance. An engineer unwilling to make a mistake is not able to do anything worthwhile.

I have chosen to ignore Dmytry because I tired of him twisting my words, and reading things into my posts that he alone seems to see. I will keep reading these forums. Should he choose to treat my opions with the respect I offer his, I will even rejoin discussion with him. If everyone agreed with me, I wouldn't have to say anything. When there is disagreement, the need is for communication. Questioning the intelligence, honesty or motives of those who disagree with you isn't communication.

Don't beat yourself up about a simple miscalculation, look at Fukushima the best scientific minds in the world have managed to cooperate to produce the "biggest radiological Kluster**** the world has ever seen" Perspective
 
  • #40
Caniche said:
Don't beat yourself up about a simple miscalculation, look at Fukushima the best scientific minds in the world have managed to cooperate to produce the "biggest radiological Kluster**** the world has ever seen" Perspective

Thanks, I won't. And Fukushima isn't really the dumbest move ever. That would either have to be launching a land campaign into Russia in winter (tried twice) or the Edsel.
 
  • #41
Einstein once that said there are only two things which are infinite: The universe and the human foolishness. But he wasn't sure with the universe...
 
  • #42
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  • #43
Consider those re-racked pools. Originally, racked with enough space between the plates so that no neutron absorbers are needed. Later on re-racked for higher density with boral plates, which if they fail, the stuff can go critical. The boral plates do not even behave as originally intended (water seeps in and reacts with aluminium, bulging the plates to the point of fuel assemblies getting stuck).
http://www.nrc.gov/reading-rm/doc-co.../sec3/196.html
The unintended is then declared to be insignificant. Right.

What are you talking about? That entire article was devoted to identifying the issue and proposing solutions to it, which it did. Maybe I missed it, but I don't remember the article saying anything about that being insignificant. In fact, it specifically said that the issue could lead to a VERY dangerous situation. The issue met the "Criteria for nuclear criticality safety".

Also, I don't follow where you take your post. As far as I can tell the issue in the article has nothing to do with your post or anything else you've linked. Are you just using it as another hazard to talk about safety?

100+ people can do a lot of things. They can design a reactor safely, or they can rationalize away unsafe changes as not degrading safety, and make very convincing arguments for that. There's the risk of a group of people doing the latter rather than the former.

And your point is what? That there is a risk? Of course there is a risk. From your posts I gather that you simply don't trust anyone in the nuclear industry enough, correct? Is there ANYTHING that we could possible link or tell you that would change your mind?

still no definite answers from those in the industry about 1 or 2.

Didn't astronuc already answer those back on page 1?
 
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  • #44
NUCENG said:
Thanks, I won't. And Fukushima isn't really the dumbest move ever. That would either have to be launching a land campaign into Russia in winter (tried twice) or the Edsel.

There you go again, your model fails to account for the wort case scenario,the Sinclair C5
 
  • #45
NUCENG said:
Thanks, I won't. And Fukushima isn't really the dumbest move ever. That would either have to be launching a land campaign into Russia in winter (tried twice) or the Edsel.
Caniche said:
There you go again, your model fails to account for the wort case scenario,the Sinclair C5

Excellent mention but the Sinclair C5 isn't a Japanese invention(mega-cringe anyway).

How about Toyota's robot that can play violin(they already have a trumpet playing one!)? For when the music stops at Fukushima.

http://afp.google.com/article/ALeqM5hmM0nL3VaYOm_ik334090WpK4Ofg"

edit: oops, the Edsel wasn't Japanese either.
 
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