The Nuclear Power Thread

[jim hardy]

Something to consider when developing an exotic nuclear fuel system.
https://www-nds.iaea.org/sgnucdat/a6.htm

That's interesting. Does Americium build up in MOX fuel early in cycle ?

 

[Astronuc]

That's interesting. Does Americium build up in MOX fuel early in cycle ?

Am-241 comes from the beta decay of Pu-241, which accumulates in UO₂ fuel as it is used. After shutdown, without a thermal neutron flux, Am-241 starts to build up. This is why burnup is limited on UO₂ fuel in countries recycling UO₂ fuel into MOX, or recycling MOX, and why reprocessing occurs as soon as possible.https://www.oecd-nea.org/pt/docs/iem/mol98/session4/SIVpaper3.pdf

See chapter 11 in this book https://books.google.com/books?id=m...297#v=onepage&q=Americium in MOX fuel&f=false

 

[jim hardy]

wow for some reason i thought Americium only fast fissioned...
wiki mistake ?

The longer spent nuclear fuel waits before reprocessing, the more 241Pu decays to americium-241, which is nonfissile (although fissionable by fast neutrons)

https://en.wikipedia.org/wiki/Plutonium-241
i didn't know it had such a cross section

http://www.osti.gov/scitech/servlets/purl/4511543/

and neutron yield., ~3 per your link.Does it build up enough concentration to account for significant reactivity ? 14 yr halflife in from Pu241, 432 years out to Np237 ? Seems it's build in fuel that's stored for a decade or two...

Please excuse my lack of fluency, i only took one reactor physics course and that was in 1968.

old jim

 

[Astronuc]

http://www.osti.gov/scitech/servlets/purl/4511543/

That's an old document, so there are better data now for the TU nuclides.

Looking at the thermal cross-sections at NNDC, Am-241 has a σ_λ of about 619 b and a σ_f = 3.14 b, so it is more likely to capture a neutron and become Am-242, which has a high thermal fission cross-section, σ_f = 2095 b, and a smaller capture cross-section, σ_λ = 219. There should be some IAEA reports that give isotopic vectors for UO₂ and RG MOX at different burnups.

 

[mheslep]

Entergy announced plans to close Fitzpatrick on Ontario, its 2nd closure announcement this month, after Pilgrim. BWR, 35 yrs old, 835 MWe, licensed through 2034.
http://www.nrc.gov/info-finder/reactors/fitz.jpg

Off the top of my head, for the last couple years the list of closed or soon to be closed US nuclear includes SONGS, Yankee, Pilgrim, Fitzpatrick.

What's going on? Cheap gas, yes, but gas is not cheaper than nuclear fuel at ~1c/kWh. One explanation: Per the NYT, Fitzpatrick employs 600, with an average annual salary $120K, or $75 million in salary alone per year spread over a single reactor plant. What's the shift staff for a gas plant? 20? Another reason: the US industry was obligated by the NRC under the maniacal Jackzo to spend $3 billion to retrofit Fukushima lessons learned, or $50 million per US plant. I imagine Entergy calculates no federal regulator can hit up their gas plants for $50 million each.

 

[wizwom]

In regards to the Nuclear plant closings, the issue is not spent fuel, or cost to run the plant - the cost per kWh is the lowest for ANY method of production.
The issue is the negative bids from renewables, making plants running baseload actually pay to feed the grid. I don't know why they continue to run at full power during those times, but I think it has to do more with cultural inertia than with physics or engineering.
So, a plant like Clinton runs $400 million in the red in 2014, and Excelon is trying to figure out how to stop losing money.

 

[mheslep]

In regards to the Nuclear plant closings, the issue is not spent fuel, or cost to run the plant - the cost per kWh is the lowest for ANY method of production.
The issue is the negative bids from renewables, making plants running baseload actually pay to feed the grid. I don't know why they continue to run at full power during those times, but I think it has to do more with cultural inertia than with physics or engineering.
So, a plant like Clinton runs $400 million in the red in 2014, and Excelon is trying to figure out how to stop losing money.

Are there some references showing this to be the case for closed/soon closing plants? This contradicts the explanation from Entergy, which cites costs. How do you get to lowest cost per kWh with a plant staff of 600 at $120K/yr each?

 

[etudiant]

Wizwom's input does highlight an interesting extra dimension in the current electric generating economy.
I had not known of 'negative bids', but am not surprised, the financial community is expert at manipulating the power markets, as was demonstrated in California.
Is it possible to put a nuclear plant into warm standby, so it could easily be spun up again when power prices improve or is that impractical?
Given that these plants take a decade to build, it seems poor policy to shutter them because of a price fluctuation which could reverse abruptly.

 

[Astronuc]

Negative pricing with wind and inexpensive natural gas (and low capital cost) has put some nuclear units at risk for closure.

I believe one or two units in the US are doing reduced power operation as a result of surplus power on the grid, but I'll have to check. The French utility EdF routinely does reduced power (and load follow and frequency control) and periodic shutdown to hot zero power (HZP) because their grid is predominantly nuclear. However, many of their units are on annual cycles. In contrast most US plants provide base load on 18 or 24 month cycles, and many try to achieve capacity factors > 90%.

 

[anorlunda]

Wizwom's input does highlight an interesting extra dimension in the current electric generating economy.
I had not known of 'negative bids', but am not surprised, the financial community is expert at manipulating the power markets, as was demonstrated in California.
Is it possible to put a nuclear plant into warm standby, so it could easily be spun up again when power prices improve or is that impractical?
Given that these plants take a decade to build, it seems poor policy to shutter them because of a price fluctuation which could reverse abruptly.

There is no need to infer improper financial manipulation. Those nuclear plants put in negative bids because to avoid expensive shutdown/restart cycles, or simply to avoid moving control rods. That is perfectly proper market behavior.

In the early 70s, the ability to "load follow" was touted as a competitive advantage. BWRs especially touted the ability to change power by varying recirc flow (and in extreme cases bypassing the HP turbine). The rates of change and the ranges of load following varied with different designs. I believe that all time champion load follower was the ancient and unique Dresden 1. However, because of the relatively low costs of nuclear power in that period, they were sought by utilities for base load. The market didn't value load following enough. Other design tradeoffs dominated and load following capabilities were not pushed as much as they could have been. Once again, perfectly proper market responses.

The more interesting engineering question is to what extent the design of a nuclear plant can be tweaked over time to optimize property B instread of the original design's optimization of A. I suspect that there are numerous success and failure stories related to that question.

 

[mheslep]

I had not known of 'negative bids', but am not surprised, the financial community is ...

Negative bids come not from some manipulative financial maneuver but from renewable energy producers who produce more than what's needed at a moment in time, yet the capacity is mandated by renewable portfolio standards and the like.

 

[etudiant]

Thank you, anorlunda and mheslep, for getting me educated.
I had not known the regulatory framework was so irrational that negative bids were a reasonable decision. It seems that little has been learned from the debacle that was deregulation in the California power market.
Stepping back, it is difficult to envision committing to a $10-20B twenty year investment targeted at this business sector. The nuclear renaissance may occur, but only under different jurisdictions.

 

[anorlunda]

I think negative bids are perfectly rational. Remember they occur only a few hours per year do they have little effect on anyone's yearly profit.

As for blaming it on renewables, they have just as much right top bud what they want as you do. The market does not belong to you.

 

[etudiant]

I have no doubt these bids are quite legal and rational, as anorlunda has pointed out.
I'm simply highlighting that such pricing indicates a regulatory malfunction which discourages long term investments such as nuclear power.

 

[anorlunda]

I'm simply highlighting that such pricing indicates a regulatory malfunction which discourages long term investments such as nuclear power.

There is no malfunction by anybody's definition. I think your understanding of energy markets and the meaning of negative bids is less than perfect.

The foremost goal of any free market is to be fair to all participants. For example, the stock market must not allow some participants to buy at lower prices than others. Deviation from that is not only wrong, it is criminal in many cases. If you want to promote nuclear (or Tesla Motors Inc., or anything else) for any reason, you may not do it via unfair biases in the energy market (or the stock market).

Negative prices: Suppose you gave your broker an order to sell IBM at a price of "-$10 or higher." That would not cause the market price of IBM to crash to -$10. Instead, you would get paid today's market clearing price for IBM (perhaps +$99). In fact, you will always succeed in selling your IBM stock unless all the other sellers had bids more negative than -$10. Indeed, your reason for the negative bid could be that your boss said, "Sell those stocks today regardless of price or you're fired." [Yes, I know that stock markets allow "sell at market" offers with no floor price, but energy future markets don't have that. Negative price bids, approximate "sell at market" offers.]

It is the same in energy markets. Negative bids appears in the bidY box every day, but only 2-3 times in the past 15 years that I remember has the market clearing price in my state ever gone negative for an hour or two. The negative bidders get paid the same market clearing price as everyone else for all those other hours. Economically, those negative bids have negligible impact on real life for any market participants. All those bidders are trying to say, is "Take my power at any price and pay me the going market rate." You can not call that a regulatory malfunction.

Therefore, in a free market, all participants including nuclear, renewable, and whatever compete on price and operating flexibility. The problem many nuclear plants had is that they were designed for 45 year lifetimes as base load units. That was the standard assumption in the 1970s, but it seems rather arrogant in retrospect. The owners were betting that their technology was not only cheaper in 1975, but that it would remain the cheapest form of generation for the next 45 years. That sounds pretty stupid today. Would you pay $2000 for a smart phone built to last 45 years, or would you rather have a phone that you can discard every year or two so you can buy a new one with the latest technology?

The wisdom of any energy investment that needs decades to pay off the investment is dubious. Heck, any technology investment of any kind that needs decades to pay off the investment is dubious.

Times change. Base load units may need to become intermediate or peakers in the future. The standard lifetime of a capital investment can change from 45 years to 5 years. Keep up with the times or die. Do not expect the energy markets to bail you out.

BTW, I've worked as a nuclear engineer myself and I've always been pro nuke. But I also worked in energy futures markets and I understand how they must work.

 

[gmax137]

... The foremost goal of any free market is to be fair to all participants. ...
Therefore, in a free market, all participants including nuclear, renewable, and whatever compete on price and operating flexibility. ...

Do you really see the present arrangement as a free market?

 

[anorlunda]

Do you really see the present arrangement as a free market?

The market in the state I'm most familiar with, New York, absolutely yes.

Some states still have the old vertically integrated monopoly model. Some have an unholy mix of both independent and utility owned generation which just begs for failure. But where generation is fully divested from the transmission owners, yes it is a free market.

 

[mheslep]

The market in the state I'm most familiar with, New York, absolutely yes.

When a utility is required to ask approval from government officials to raise utility rates, ask approval to build new capacity, how does that situation qualify as laissez faire?

 

[anorlunda]

When a utility is required to ask approval from government officials to raise utility rates, ask approval to build new capacity, how does that situation qualify as laissez faire?

The wholesale energy market matches sellers of energy (owners of generation) with buyers (utilities that serve retail customers) and with owners of the transmission (also utilities, but not necessarily the same utilities as the loads. In states where none of the generation is owned by the utilities, that is a free and open market. I have sat through meetings where the competing interests debate the rules for the markets, and then vote on them. I can tell you that it is not government that made those rules.

However, at the retail and transmission ends, we still have regulated monopoly utilities. Competition can't work at that level because we don't want an additional set of poles and wires on each street for each additional competitor.

So yes, those utilities are regulated as you say. The difference is that they used to own the power plants also. Now they buy their energy on the free wholesale market. For example, take the famous Con Ed in NYC. Con Ed used to own its own power plants. Con Ed was forced to sell all those power plants to private parties who are not utilities, and it buys energy from the independent power plant owners. It buys about 50% on the free wholesale market in New York, and 50% via long-term contracts with power plant owners. But Con Ed's retail rates are dictated by the state government.

To repeat, the wholesale market is free (in some states), the retail market is strictly regulated like it always was. To consumers, the wholesale market is mostly invisible. Does that explain?

 

[mheslep]

Yes, agreed, I'm aware that the wholesale market is unregulated, the retail end as you describe. However the two, wholesale and retail, are of course coupled, so I think "free" goes to far as a description, in the way that, say, the smartphone market is free.

 

[etudiant]

Clearly there are different visions of the best way to provide electricity and other utilities which are essential.
The one approach is to provide controlled service, designed to be abundant and reliable, which usually implies lots of excess capacity, with associated costs, as well as restricted market entry. The pre deregulation air service in the US was an excellent example, 50% load factors and high fares, never worry about getting a seat,. That is not true any more as that regulatory approach has changed to a free market focus.
The other approach is that the services should be freely supplied, with competition regulating the market. In air transport, this has led to dramatic supplier consolidation and much lower fares, albeit at reduced levels of service. How easily this model can be applied to the electrical market, where there can be large stranded costs generated by the change is still open. Also, the example of the cable industry suggests oligopoly control of supply and abusive market behavior are real concerns.

 

[anorlunda]

Also, the example of the cable industry suggests oligopoly control of supply and abusive market behavior are real concerns.

Sure they are concerns, but don't assume that markets are static and unable to adapt.

The organizations that run the markets (called ISOs) are governed by the market participants (MPs). The MPs make the rules. If any class of MPs feel that they are being treated unfairly, they lobby to change the rules. If that fails, they complain to FERC (which does have regulatory authority over the ISOs). If that fails, they can elect to buy or sell their energy outside of the markets. Participation is voluntary, so an unfair or abusive market is not sustainable.

My point is that oligopoly control of supply and abusive market behavior are not sustainable in voluntary markets that are able to adapt.

 

[krater]

I think "free" goes to far as a description, in the way that, say, the smartphone market is free.

Smartphones are but an expensive novelty without the huge communication infrastructure that gives them much of their utility value. Said infrastructure is heavily regulated by government agencies. The power grid is not identical but obviously definitions of "free" markets can get complicated in the modern world, that is the whole term has become to some degree subjective.

 

[Astronuc]

TerraPower publications - http://terrapower.com/publications

 

[Astronuc]

World starts up 10, shuts down eight, nuclear reactors in 2015
http://www.world-nuclear-news.org/N...wn-eight-nuclear-reactors-in-2015-411601.html

Last year saw new reactors with total capacity of 9497 MWe connected to the grid, up from the 4763 MWe added in 2014. China added eight units, which were, in month order: Fangjiashan 2, Yangjiang 2, Hongyanhe 3, Ningde 3, Fuqing 2, Yangjiang 3, Fangchenggang 1 and Changjiang 1. South Korea and Russia added Shin Wolsong 2 and Beloyarsk 4.

Uprates saw a further 484 MWe added. South Korea, the USA and Sweden accounted for 19 MWe, 290 MWe and 175 MWe of this total. There were two downrates, of 19 MWe each, at South Korea's Wolsong 3 and 4.

As of 31 December 2015, there were 439 reactors in operation, with a total 382.2 GWe. For comparison, at the start of 2015 there were 437 operable reactors and a total nuclear generating capacity of some 377.7 GWe.

Apparently, China's goal is to have several hundred nuclear plants by 2040/2050 as part of a plan to raise standards of living for 800 million people.

Meanwhile - "Unit 3 of South Korea's Shin Kori APR-1400 nuclear power plant was connected to the grid on 15 January and has started supplying electricity, plant owner Korea Hydro and Nuclear Power (KHNP) announced yesterday."
http://www.world-nuclear-news.org/NN-Grid-connection-for-first-Korean-APR-1400-1901164.html

 

[mheslep]

Yesterday a Japanese court ordered two of the four reactors restarted since Fukushima to shut down.
http://www.bbc.com/news/world-asia-35761440

 

[xpell]

Yesterday a Japanese court ordered two of the four reactors restarted since Fukushima to shut down.
http://www.bbc.com/news/world-asia-35761440

Japanese public opinion on nuclear power flipped from 65% for to 70% against with the Fukushima disaster, and this change seems to be persistent. Municipalities which used to roll out the red carpet for nuclear power are now extremely wary of their voters' opinion. Courts which systematically ruled for nuclear power now don't. For what it's worth, according to a couple Japanese acquaintances who used to be pro and now are against, the decades-old campaign reassuring everyone that a nuclear accident was impossible in Japan and that the anti-nuclear crowd were illiterate bumpkins if not dangerous anarchists or the like backfired massively as the reactor buildings blew up on live international TV. Actually it's quite obvious: if you have been bombarded all your life with a "nuclear is totally safe" campaign, then you see those buildings blowing up in pieces on live TV, you're not going to trust them much anymore. The helicopters hovering above the wrecked plant with buckets of God-knows-what felt really "Chernobyl-ish." The damage actually caused by the tsunami in nearby areas also felt quite "Pripyat-ish." Images are very powerful and stick deep.

After such a breakdown of trust, the intricacies of the "hey they're just hydrogen explosions!" argument didn't stick much. The contradictory information about radioactive releases and the true state of the reactors and the storage pools didn't help. And the information about how TEPCO ignored the seismic history of the area up to the point of building 5 to 10-meter defenses in a region with registered 38-meter tsunamis (actually the tsunami hitting the Fukushima NPP proper was "only" about http://www.oecd-nea.org/news/press-kits/fukushima.html), or the seismic problems at the "moving nuclear plant", as well as other heavy violations of nuclear safety, definitely didn't help at all. Public trust in their nuclear industry was totally shattered and people went heavily against, even in the face of rising energy prices. No wonder that restarting those plants is now a political and judicial nightmare.

I'm reasonably pro-nuclear, but honestly I can't blame the Japanese for this. They were basically betrayed in their trust during their entire lifetimes, and most of them have reacted as easily expected. I'd like to add that any campaign based on the "accidents can't happen here" idea (nuclear or otherwise) is always a very, very stupid move.

 

[mheslep]

If the nuclear discussion is to be refraimed in Japan, it should to convey that the against-nuclear position is actually the "switch from nuclear" to coal and gas, making clear that while the Fukushima accident has been expensive, the radiation didn't kill anyone but increased coal emissions will.

 

[xpell]

If the nuclear discussion is to be refraimed in Japan, it should to convey that the against-nuclear position is actually the "switch from nuclear" to coal and gas, making clear that while the Fukushima accident has been expensive, the radiation didn't kill anyone but increased coal emissions will.

Fully agreed, that's one of the many reasons why I'm "reasonably pro-nuclear." But you know, that's not how the general population uses to react when facing such facts. Actually I'd say that the discussion has already been reframed, and that new frame is quite anti. See, recently the Sakurajima volcano has been erupting. Not a big deal in the Pacific Ring of Fire, and actually this volcano has been intermittently erupting for thousand of years, with an increased activity since 1955. It happens to be that the Sendai NPP, the only fully reactivated one, was built about 50 km away. With these last eruptions, a major talking point was if it was safe or wise to have nuclear power plants operating in a highly seismic, highly volcanic country. That's something you would rarely have heard outside of "radical" circles in the old pre-Fukushima-disaster times. When Sendai was reactivated in August 2015, the very former Prime Minister during the disaster Naoto Kan, not exactly an eco-anarchist fighting the system, attended the rally against the restart telling to the fellow protesters: "We don't need nuclear plants." Go imagine your former President or Prime Minister doing that in your country. You get the mood.

I must clarify that there's still some uncertainty among sections of the public ("anti" scores 70% in the polls, but "strong anti" seems to be lower at about 53%), and the current Government is doing as much as they can to "rescue" some trust for the nuclear industry and regulators and restart plants. But if they have just one more incident, not necessarily "another Fukushima" but just a worrying incident, I'd bet dollars to donuts that nuclear power is dead in Japan.

 

[Jon Richfield]

I agree with the foregoing postings on Fukushima. Although I am quite strongly pro-nuke, my support is predicated on the assumption that nuclear power can be safe and should be safe (make that "must be safe").
The Fukushima meltdowns horrified me, because in my innocence as a non-nuclear non-engineer, I had been under the impression that all western (yeah, yeah I know, I know, including Japan!) power plants included passive fail-safe systems that did not rely on power or importation of water or whatever was necessary to snuff out and contain excursions even if everyone in the plant had dropped dead. (Asteroid strike? If we get a serious asteroid strike, we will have worse things to worry about than a few incidental nukes getting in the way!)
Now, however naive I was, I still insist that if that is not how things are, it is how things should and MUST be, because although one could argue that to design nuclear power plants for passive containment would double their cost (probably not really anything so extravagant, but choose a figure), but even without the political and social costs, the cost of NOT having done so could double the costs anyway (probably not really anything so conservative, but choose a figure). Would anyone believe that the Fukushima failure doubled the effective costs of the power stations? More than doubled? Any bets?
And if such safety measures were to make the power plant uneconomic, that would mean that in such a situation nuclear power would be uneconomic, though to my mind all it would show is that you had the wrong engineers on the job (and maybe the wrong economists as well; to say nothing of politicians).
Another thing is that lately developments in so-called renewable energy (bloody inaccurate name, but never mind) have been making such strides, and in the face of numerous assurances that it never could happen, that it is thoroughly possible that fossil fuels, whether carbon-based or fissionable-fuel-based could be phased out almost entirely in favour of sustainable energy sources before the end of the century, even though it also is possible to use nuclear power safely and economically. But the likes of idiocies like Chernobyl and Fukushima and even TMI will be what excludes nukes from consideration.
In any case, burning fossil fuels makes as much sense as burning banknotes, except to the social parasites who wish to perpetuate the practice because it is what makes them rich while impoverishing humanity and the planet.