Nuclear power in US - safety against unforeseen situations.

[Dmytry]

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.

 

[Astronuc]

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.

 

[gmax137]

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?

 

[Dmytry]

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.

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 .

 

[Dmytry]

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.

 

[Drakkith]

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?

 

[Dmytry]

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

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

 

[NUCENG]

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.

 

[Caniche]

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

 

[NUCENG]

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.

 

[clancy688]

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...

 

[Astronuc]

There is a fair amount of oversight of the safety of US plants.

The NRC has a program - http://www.nrc.gov/reactors/operating/ops-experience.html

and there is a program by INPO, and internal programs at the utilities.

 

[Drakkith]

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?

 

[Caniche]

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

 

[Danuta]

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

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.