Talk:Nuclear reactor

From Wikipedia, the free encyclopedia

You have new messages (last change).
Former FA This article is a former featured article candidate. Please view its sub-page to see why the nomination failed. For older candidates, please check the archive.

Contents

[edit] Integral Fast Reactor

IMHO we need to build a section on the IFR. It is an extreamly important advanced design and it was shut down for political reasons. Combined with this we need to talk about High Temperature Electrolysis and what this can mean for the hydrogen economy... since it can be up to 55% efficient. This has the potential to replace steam reformation which can currently produce hydrogen at about 0.65 per lbs.

We currently have a hydrogen source from steam reformation, however it is less energy efficient than just buring the methane. Not only this, the methane source IS NOT GOING TO BE THERE. Here is why I say this. Canada produces about 6.3TCF per year and exports about 55% to the USA. Source - BP statistical review. Please look it up and correct my figures if they are not correct. Now Tar Sands operations are expected to ramp up to about 5 million barrels per day by 2015-2020.

In order for this to happen they need a source of hydrogen which in the past has been steam reformation (or taken straight from the methane... I need to check this). In fact Tar Sands by my esitmates (which will need to be recalculated) the amount of NG required will be fully 1/2 of Canada's expected production by 2020. This means that Canada has to completely eliminate NG exports to the USA in order to produce the synthetic crude. Since the USA is already short of natural gas, another option might be to try to wean the lion's share of Canadian current consumption in order to make some gas available to the USA. A third alternative is LNG imports and perhaps we can import what we need.

However, we do have the nuclear option and the IFR combined with high temp electolysis supporting tar sands operations would be a very attractive option. The waste heat can be turned into process steam and tar sands needs this as well.

If we do this, then we are taking the first steps into the hydrogen economy. It is just that we are hooking the hydrogen up to carbon atoms and storing it as synthetic oil instead of trying to store it in a tank by itself.

CANDU can be used in place of IFR but the temps are about 300C instead of the 850C required by the High Temp Electrolysis process. By simply increasing the pressure we can raise the tmep but I was unable to find out if this is compatible with the High Temp Electrolyiss process.

In any event, all of this should be written up into a series of articals. We should definately delinate the short sighteness of the political reasoning of 1994 when congress shut down the IFR program at Argonne Labs. If as I expect we start to see a MAJOR energy crisis develope then having these reasons written up will provide excellent background information of why people are freezing their butts off in the dark and why we are building up nuclear wastes when we clearly have excellent alternatives like burning up the damn actinides in an IFR.

Can you give us some good references on that? I found one [1], written by a fan, but a few with more technical details and criticisms would be helpful. --Andrew 08:18, Dec 24, 2004 (UTC)
Ok I wrote Integral Fast Reactor. Go to town. --Andrew 01:47, Feb 3, 2005 (UTC)

[edit] Natural Reactors

Can someone add information on the "natural nuclear reactors" that sometimes form in Uranium deposits.. I know there's at least one somewhere in Africa.. I'll try to find a source, but I'm sure someone out there right now knows exactly what I'm talking about. --Dante Alighieri 22:22 Dec 5, 2002 (UTC)

Gabon I think is the only site yet discovered. I'll add something when I have a moment, or do a search on "gabon fossil nuclear reactor" or similar. Or there's a link to some info in Talk:Plutonium Andrewa 21:54 Mar 17, 2003 (UTC)

I have just been studying the topic and have a little information from "Radiochemistry and Nuclear Methods of Analysis" a text by Ehmann and Vance (Chemical Analysis volume 116 Wiley-Interscience Publication 1991). The possible site of the natural nuclear reactor was in the Oklo Mine in Gabon, Africa. Some of the evidence which points to the existance of a natural reactor are higher than average decreases in isotopic enrichment of U-235 (used as fuel), higher than average decreases in isotopic enrichment of isotopes of other elements that are neutron absorbersw (i.e. the isotopes that were neutron absorbers are decreased with respect to those that are not),and soil containing sufficient water to slow cosmic neutrons to acceptable energies for initiation of a fission reaction.

[edit] Danger of NP

Copied from the danger of nuclear power. I think most of the points are already in the article.

Nuclear power is considered to be unsafe by some, who claim:

  • There is no solution to the problems related to disposal of highly radioactive waste.
  • There is no solution and often no money to safely decommission a nuclear reactor.
  • The mining, processing and handling of nuclear materials is spreading radioactive waste into our environment.
  • The plants are potential terrorist targets.
  • Many plants have had accidents in which radioactive materials have been leaked into the environment.
  • During regular operation of these plants, many different radionuclides are released into the environment.
  • The fuel and waste from the plants has facilitated the spread of nuclear weapons across the planet.
I didn't notice before, but that last comment is particularly controversial. There have been dual-use plants, certainly, but nobody has yet produced a bomb by diverting material from a plant built purely as a power reactor, and there are good reasons for thinking nobody ever will.
This whole section was POV, in my opinion. In hindsight there is also some possibility that the attempt to redefine the term LWR to include Chernobyl, which I addressed below, was politically motivated. Andrewa 09:03 30 Jun 2003 (UTC)

Most of these points are false. The idea of no solution for radioactive wastes is a perfect example because we have fuel re-processing in Europe and Japan which gets rid of the Pu, then we have spallation and IFR technology literally sitting on the door step.

About the only criticm that is valid is that when you have vast amounts of energy in a small place then any problems can take on a sinister new meaning. This is true of any concentrated energy sources such as explosives, oil tankers and expecially the LNG tankers, big bottles of propane and so forth. It isn't the nuclear character which is the problem - it is the concentration of the energy.


Actually, in regards to the danger of nuclear power, most of these points are correct, verifiable and with historical precedent. I would also like to point out that fuel re-processing is neither a solution for nuclear waste, nor as you erroneously stated, does it get rid of Pu. None of the technologies you mentioned either reduce the radioactive hazard of nuclear waste or provide a solution for it's long term storage. I think that it's extremely important to be objective about this type of article, but ignoring proven facts just because they don't fit with your own view of nuclear energy or because they are sometimes spouted by radical environmental groups shouldn't preclude them from this article. I think it would be highly pertinent, for example, to include links to the websites of such groups in the interest of balance and to allow the reader to make their own conclusions.

Fuel reprocessing can remove all but trace amounts of uranium, neptunium, plutonium, americium, and curium, and all those can be used to fuel a fast-neutron reactor.
The remaining waste will only be hazardous for centuries instead of millennia.
That does indeed get rid of the plutonium, reduce the radioactive hazard, and provide a solution for long-term storage. Oralloy 05:10, 20 December 2005 (UTC)
Many of these problems are either A. Negligent, B. False, or C. Solvable. I also agree that these are POV and should not be introduced into the article.--128.227.142.136 15:40, 25 September 2006 (UTC)

[edit] LWR vs RBMK vs PWR know your terminology

I hope I have not been too harsh in my comment, calling what I have corrected a "major error". The original said a light water reactor was so called because of its *cooling*. It is in fact called a light water reactor because of its *moderator*. I thought it very important to make it clear because it's a common mistake, and some people even confidently tell me that Chernobyl was a PWR. Of course it was not, it was not an LWR at all. It *was* light water cooled, but the RBMK has very little in common with a PWR (more in common with a BWR maybe, but still not a lot). Andrewa 21:54 Mar 17, 2003 (UTC)

[edit] Economics

The economic discussion is misleading. Current production costs (fuel+O&M+capital and, for nuclear, + D&D) of electricity from nuclear power plants are in the $15-$17/MWhrE range, coal in the mid $20's, and natural gas in the $40's and climbing every day with gas prices. Should check the facts against recent FERC reporting.


Added this information. The main problem isn't the cost per megawatt, the problem is the total cost per plant. Roadrunner 21:53, 1 Apr 2004 (UTC)
added this problem: reconversion of several millions of tons of uraniumhexafluoride worldwide. who`s gonna pay for that?? repaint the steel containers every 50 years for the next some billion years ?now think about and let us know. TREE, 3 april
added this problem : tritium (radioactive hydrogen) concentration in public drinking water has a tenfold increase(~1945-2003),tendency rising. hydrogen is essential for genetic "language". how do you calculate the cost of a cripple?? ten cripples? lots of them? TREE, 3april
I cut the above link out of the article because the site is not very well done, hard to navigate and I am not sure how good the study actually is. But it seems to go into some technical detail and may be of value - so I am pasting it here for reference, and maybe someone can glean some information from it and include the information into the article and then use the study as a reference. Until then I say we keep it off of the article page. Trelvis
  • During regular operation of these plants, radiation is released into local environments.

that is how you call it. it is definitely wrong and misleading.correct term is: "radioactive matter" and not just "radiation" you should be educated enough to recognize the difference.plus you are supposed not to tell lies.now please re-add my link to the stormsmith(elstatconsultant) website and let the people judge themselves. the work is profound and very well done . let me add ,that i`ve been in the nukebusiness myself. like mine,your head is round,to give way for thoughts to change direction sometimes . yours TREE

If the work on the stormsmith site is profound and very well done, then by all means work the material into this article, and cite that page. If you think parts of this article are wrong or misleading, please change them and help us make this article more accurate. If you simply want to complain while questioning other contributor's educations and head shapes, then you will be frustrated to learn you will for the most part be ignored. Trelvis 17:01, Apr 2, 2004 (UTC)

[edit] Cooling Tower

For a change from the wrangling: Practically every analytic geometry book has a picture of a nuclear reactor cooling tower as an example of a hyperboloid of revolution. We have one here, in this article. Why are the cooling towers that shape? Are they actually that shape in most plants? --Andrew 07:11, Apr 25, 2004 (UTC)

I think most reactors are sited near some body of water - river, lake, ocean - which they use as a heat sink, but yes, those that have cooling towers do use this shape. I don't know the math, but the shape plus the heat from the reactor creates a strong draft in the chimney so that fans aren't needed to move air through the tower. Altough large, the structure is relatively cheap because, as the hyperboloid of revolution shows, it can be built out of straight pieces. --wwoods 17:33, 3 May 2004 (UTC)
The "nuclear" cooling tower is an effective way to increase the convection cooling of a liquid. The cloud coming out of the tower is always water vapor (not steam) and the inside of the cooling tower is quite cold. Cooling towers are used in any temperature difference driven power generator (basically everything but hydroelectric and some solar). This is because the effeciency of a generator is proportional to the difference in temperatures between the engine and the coolant. People often see a cooling tower and assume that the power plant is nuclear, but this usually isn't the case. --Ignignot 13:28, Sep 1, 2004 (UTC)

[edit] Gabon reactor

If it is not too late to comment, there are many articles on the OKLO (Gabon) reactors (there were more than one) listed on the web - a good one to start with was prepared by the American Nuclear Society It is at http://www.ans.org/pi/np/oklo/.

There is still research going on in analysing the neutronics of the reactor.

Dave Eissenberg eissenbd@sover.net

Quote from the article:

"seawater has enough uranium to power the world's current industrial civilization until the sun becomes a red giant"

This is not true. Current industrial civilisation needs about 10 TW of power. Even if we can get 1014 J out of 1 kg of uranium (slightly more than the total energy released by fission), we would need 0.1 kg of uranium per second, or about 1.6 × 1016 kg in 5 billion years, the estimated time till sun becomes a red giant. According to webelements [2], there are 3.3 ppb per weight uranium in seawater. So we would need about 4.8 × 1024 kg seawater, which is more than three quaters of the earth's mass. There is not that much seawater on earth.

With a volume of the oceans of about 109 km3 there's about 1021 kg of water in the oceans. With a more realistic estimate of how much energy one can get out of uranium, the 10 TW could only be produced for a few 105 years. 193.171.121.30 18:56, 30 Jun 2004 (UTC)

While the quote is overblown, the amount of U that can be extracted from seawater is much larger than the amount currently in solution in seawater. Water circulates through the upper crust and can dissolve more. Not necessarily the most cost-effective method of mining it, but hey...
--wwoods 19:31, 30 Jun 2004 (UTC)
True, but then it was at least misleading because it said "... seawater has enough uranium ...". 193.171.121.30 21:43, 12 Jul 2004 (UTC)

Um...wow...

This article is bad, but I've no idea how to fix it.

Issues:

1. Blatantly POV at the end, in the nonproliferation section...Not to mention contradictory.

First ir says the US "claims" NK has nuclear weapons.

Then it says the NPT "clearly" has not prevented NK from producing them.

2. "This seems like good public policy, because of the good safety record of commercial aircraft."

Whether it is or isn't (and I think it is), how is this NPOV?

--Penta 23:32, 1 Jul 2004 (UTC)

The NPOV phrases Penta mentions probably shouldn't be in this article at all - the article is about nuclear reactors, and there is a separate article (which this article links to) on nuclear proliferation. If proliferation is mentioned here, it should be strictly in terms of how it relates to the operation of (civilian or military) nuclear reactors. --Dachannien 20:30, 2 Nov 2004 (UTC)

The article lists Pebble bed reactors as the most common type of modern gas-cooled reactor -- am I wrong in my belief that there are no operational PBR's other than research reactors? Are there any PBR's that are actually providing power to residential/industrial/governmental users? Not attacking the concept of PBR's, just questioning the use of "common" in this context.

If I recall correctly, South Africa is producing commercial PBR's. --Ignignot 13:35, Sep 1, 2004 (UTC)

The end of the article needs to be cleaned up. I'm not even sure the natural nuclear reactors section deserves its own heading; the "proponents say..." paragraph is completely inane and sounds like it was made up on the spot. With that paragraph removed the entire section is a couple sentences.

[edit] Ongoing Edits

Over the next week or so I'll be editing this article to improve it. I'm shocked at how poorly written it is. Almost every sentence in the first section has its own paragraph. The entire article seems to focus more on the debate about use of nuclear power instead of the process of producing energy from a nuclear reaction, which should be the main thrust. The entire thing needs to be reorganized, and much needs to be rewritten into better prose. Please post any comments about my edits here. I'll put up a sign saying I'm editing when I have the page open. --Ignignot 13:40, Sep 1, 2004 (UTC)

[edit] Number of active reactors.

"In 2000, there were 438 [...]

In 2001, there were 104" Is this really true? Do we have references?Rich Farmbrough 10:54, 6 Oct 2004 (UTC)

As of September 30, 2004: 438 worldwide, 103 USA
http://www.uic.com.au/reactors.htm
Background: Throughout the World, there were 438 commercial nuclear generating units with a total capacity of about 351 gigawatts.
http://www.eia.doe.gov/cneaf/nuclear/page/nuc_reactors/reactsum2.html
Introduction: As of August 3, 2004, there are 104 commercial nuclear generating units that are fully licensed by the U.S. Nuclear Regulatory Commission (NRC) to operate in the United States.
http://www.eia.doe.gov/cneaf/nuclear/page/nuc_reactors/reactsum.html
—wwoods 15:23, 6 Oct 2004 (UTC)

[edit] Removed text

From the bullet point on fast reactors:

This type of reactor is used in some mobile applications, where space constraints are a major concern,

I don't think that's true. The thermalised units used by the US navy are at least as successful as the liquid metal cooled fast reactors of the Soviet navy. There may be advantages to this class of propulsion unit, but they have yet to be proven. Andrewa 06:22, 26 Nov 2004 (UTC)


[edit] Obsolete v. Obsolescent

The UK still has several active Magnox Reactors, and the one at Wylfa has several more years left. The AGRs have no announced closure programme. The article as a whole is too US-centred.

Linuxlad 08:56, 26 Nov 2004 (UTC)

Hyperdictionary defines obsolescent as becoming obsolete. This seems an accurate description of the three classes of reactor listed. All are still in service, but it is doubtful that any new ones will be built as power stations. I add that disclaimer because North Korea has built several Magnox plants apparently as part of a weapons project. In hindsight the AGR project was doomed from the start because the proposed beryllium based fuel cladding failed under neutron irradiation (the work that showed this was done here in Australia at HIFAR).
Wikipedia has a chronic problem with US-centricity, and always will IMO. By all means correct the balance. But IMO if the UK was to order more NPPs right now, they'd be PWRs just like the last one was. Andrewa 19:55, 26 Nov 2004 (UTC)

[edit] New article

This article currently covers a great breadth of subjects, from types of nuclear reactor to nuclear power stations. I've replaced the redirect at nuclear power plant by a stub, and propose to progressively move material from this article to more suitable places, including the new stub. Help of course welcome! Andrewa 21:09, 26 Nov 2004 (UTC)

-you should use that article for discussion of the nuclear fission reactor, and not redirect Nuclear Power here - that should be a disambuguation page pointing to Nuclear Power Plant or History of Nuclear Power. Any thoughts (ricjl)

[edit] Nuclear Reactor Types

Can someone add the different types or make it more clear. This article talks about a type IV reactor.

Researchers from the US Government's Idaho National Engineering and Environmental Laboratory (INELL) and the private company Ceramatec say a computer model shows they could separate hydrogen from hot water by using a nuclear reactor.
The method would yield more hydrogen than does electrolysis, which runs electricity through water to separate hydrogen and oxygen.
The researchers say the conversion rate of water into hydrogen ranges between 45 and 50 per cent in high temperatures, compared with about 30 per cent in electrolysis.
"This is a breakthrough ... [and] a crucial first step toward large-scale production of hydrogen from water, rather than from fossil fuels," said Stephen Herring, consulting engineer at INELL.
Mr Herring says the nuclear reactor method should be cheaper and more environmentally friendly.
However, the method would work with Generation IV nuclear reactors, which the United States no longer makes.

Using Reactors to Extract hydrogen

Thanks --Llbbl 15:21, 30 Nov 2004 (UTC) i need someone really bad!

Someone may want to add something about Generation IV reactors or other critical systems, or the six reactor variations listed in that article. I'm not sure where to best put them in since many of them are paper designs and have not been used. Should they be under # 5.3 Other types of reactors or # 5.4 Advanced reactors? Lcolson 01:04, 28 November 2005 (UTC)
I'd put them in a new section titled "Generation IV" since they are more advanced than the reactors in the "advanced" section.
And maybe mention of the Very High Temperature Reactor in "the future of the industry" because it has been selected for the most aggressive funding by the US.
Regarding the Australian article, I'm not sure that last line makes any sense. There may come a time when the US no longer makes Generation IV systems, but no one in the world will even *start* making them for another couple decades. Oralloy 06:49, 20 December 2005 (UTC)

[edit] Trigor's edit

I have erased claim that nuclear waste is stored in unprotected place and that is vulnerable to terror attack in most plants. No offense but that is not truth because this waste has containment and most often it is in reactor containment itself. I have added the link. Also I have added some data about terrorist attacks as well as link.

I have pointed out that there is no proof that low level radiation is harmful.

I have also pointed out that there are uses for depleted uranium.

Please write if you are unpleased with edit.

Thanks for the references; I cleaned up the formatting and grammar a bit. Please do be careful to avoid duplicating content; a few of the things that were added were there just a paragraph before. To be fair, the article is already full of duplication and needs cleanup, but let's try not to make it any worse... --Andrew 03:59, Feb 2, 2005 (UTC)

I agree with all of your comments save one. One regarding low level radiation. ICRP said in theirs recommendations that low levels of radiation to general population are not concern and that there is indeed no proof that they can cause any injury. If one 1mSv is problem than perhaps people should also know that someone who lives in Balkan will receive 2mSv, someone in Sweden 4mSv and someone in Dower 7msV but to make it simple I have just put what I did. Do you think that that is biased and why?

Thanks for your help :)

TRIGOR

(changed indentation for clarity)
I said that the dangers of low-dose radiation are controversial because they are. There have been a bunch of studies on radiation hormesis that suggest that low doses may actually be beneficial; there are agencies (often coalitions of nuclear power companies, who may be biased but may also know more) who claim it's not dangerous; and there are (many!) groups who claim it's very dangerous no matter the level (the linear no-threshold model). So this is a subject in which one good reference is not enough; you'd need several on each side, and this is not necessarily the place for that. So I flagged it as controversial (regardless of what I, personally, believe).
In practical terms, also, if this article says "it's safe", people will be forever coming in and changing it to "no it's not"; if we say "it's dangerous", people will forever be changing it to "it's perfectly safe". At least if we flag it as controversial and take a neutral point of view, some of them will stop and think. --Andrew 02:00, Feb 3, 2005 (UTC).

Official stance of IAEA, ICRP and Association of world's nuclear operators and many others is that it is safe. That is official position based on conclusive and verifiable body of evidence. No official government and international agency has claimed that it is dangerous. Debate between small and sometimes pseudo scientific groups should not have place in this article. I believe that if you reject to say it is safe than you could at least cite opinion of ICRP and NRC. These agencies do not see controversy and that can be read on their respectful websites.

Sincerely Trigor

I have to agree with Andrew. We should probably list LNT, hormesis and the worst than LNT theorys. This should probably be at Ionizing radiation, this article is already getting a little long. pstudier 03:52, 2005 Feb 3 (UTC)

[edit] Old "Reactor design section"

In the vast majority of the world's nuclear power plants, heat energy generated by fissioning uranium fuel is collected in purified water and is carried away from the reactor's core either as steam in boiling water reactors or as superheated water in pressurized-water reactors.

In a pressurized-water reactor, the high temperature water in the primary cooling loop is used to transfer heat energy to a secondary loop for the creation of steam. In either a boiling-water or pressurized-water installation, steam under high pressure is the medium used to transfer the nuclear reactor's heat energy to a turbine that mechanically turns an electrical generator.

Boiling-water and pressurized-water reactors are called light water reactors, because they utilize ordinary water as the moderator. In all light water reactors to date, this water is also used to transfer the heat from reactor to turbine in the electricity generation process. In other reactor designs, the heat may be transferred by light water, pressurized heavy water, helium, liquid sodium, or another substance.

[edit] Energy development WikiProject

Please add Wikipedia:WikiProject Energy development to your Watchlists and participate in any polls and discussion there. Thanks in advance. We really need some additional input. We are kind of at a standstill on some issues. Tom Haws 05:50, Feb 26, 2005 (UTC)

[edit] Operational Safety

What about operational safety? For example, I've been reading the us government accident reports on criticality accidents alone, and they're pretty disturbing. For example, the technicians responsible for the Tokaimura incident weren't even informed what a criticality was! Public information archived before it was "yanked" by 9/11 hysteria can be found here:http://www.fas.org/sgp/othergov/doe/lanl/index.html

Tokaimura was not a nuclear reactor facility. I am not defending anything, but it wouldn't belong in a Nuclear reactor article. I had a quick scan through the article lists but couldn't see any really relevant ones; can you be more specific. Dabbler 12:35, 28 Feb 2005 (UTC)

[edit] Gas / Vapor Core Reactors

Why is there no mention of Gas Core or Vapor Core reactors? I have heard of these ideas several times from other sources. I guess I should just be bold and start it.

Perhaps you are thinking of Gaseous fission reactors, a kind of nuclear thermal rocket? They're still very speculative.
Currently, this page is focused on reactors used for commercial power; much of the information belongs on nuclear power plant. This page could then be generalized to discuss all sorts of nuclear reactors. --Andrew 19:51, Mar 10, 2005 (UTC)
Vapor-Core Reactors offer very high efficiency, but will be quite a ways into the distant future. Even molten-core reactors, while having a representative (the Molten Salt Reactor) in the Generation IV reactor initiative, are not likely to be built for quite some time. Oralloy 07:54, 20 December 2005 (UTC)

[edit] Separate nuclear power

Shouldn't we have a seperate article for nuclear power where the theoretical process is described? This article should be about the reactors themselves, their commercial applications and all that. Peter Isotalo 13:24, Mar 30, 2005 (UTC)

Well, we currently have a page for nuclear power plant which seems to be what you are talking about. I'm not sure what's wrong about the current article, except perhaps the section on their technical workings could be scaled down a bit and shifted to another article (sort of how nuclear weapons design is an offshoot of nuclear weapon). --Fastfission 17:35, 30 Mar 2005 (UTC)
Well, if there's a nuclear power plant, then this article should definetly be nuclear power and nuclear reactor should be a redirect to nuclear power plant. Doesn't that seem logical to you? Peter Isotalo 20:56, Mar 30, 2005 (UTC)
Hmm, it sounds like some refactoring is in order. We want nuclear power, nuclear power plant, and nuclear reactor articles (or redirects). It seems to me that nuclear reactor ought to cover all types of nuclear reactor, including those for electrical power generation, vehicle propulsion, research, and plutonium production (for example, the Windscale reactor that caught fire was incapable of producing electrical or other power, as the cooling air was vented directly to the chimney). Nuclear power plant ought to contain information on those aspects of nuclear reactors specific to nuclear power generation (cooling towers, gas turbines, proliferation risks, when was the first nuclear power station built). Nuclear power should be on the idea of nuclear power generation, its history and politics, environmental impact, etcetera.
Does this sound reasonable? I think the most important point is that nuclear reactor should not be restricted to those used for power generation. Maybe the other two should be a single article, although I think they are notionally different enough to warrant two articles.
As for where the text currently at this article belongs, that's a different question, which we can't answer until we figure out what should go where. --Andrew 22:18, Mar 30, 2005 (UTC)
I created nuclear power; all three pagesneed tidying. --Andrew 23:10, Mar 30, 2005 (UTC)

[edit] David Hahn's nuclear reactor

The contraption that David Hahn built was in fact a nuclear reactor - not a critical one, nor did it carry out chain reactions, but it did produce (some) fissile material by direct exposure to neutron radiation. It certainly produced other radioactive material by neutron activation as well.

I think this is semantics: by the definition we give, a nuclear reactor need not have a critical mass; all that needs to happen is that nuclear transformations need to happen in a controlled way.

But the fact remains that as described in the Harper article, his machine could and did produce (some) fissile materials. Do you have another reference? --Andrew 21:25, Apr 26, 2005 (UTC)

Well, there are Subcritical reactor so I won't quibble about it being critical. However, his neutron source was radium/polonium and aluminum/beryllium based. From Neutron source Neutrons are liberated when beryllium is hit by alpha particles at about 30 neutrons/million alpha particles. Not enough neutrons to transmute any significant amount of material. The book reported that the radioactivity steadily increased, but this was from the buildup of daughters of thorium (see http://www.uic.com.au/neAp2.htm):

Th-232 -> Ra-228 + alpha, half life 14 billion years
Ra-228 -> Ac-228 + beta, half life 5.8 years
Ac-228 -> Th-228 + beta, half life 1.9 years
Th-228 -> Pb-208 + 5 alphas + 2 beta, chain of several reactions, max half life 3.6 days

A fresh sample of Thorium a couple weeks old would be pure Th-232. Over the next several years all these daughters would build up, increasing the radioactivity of the sample. The book is very confused on this point. Apparently, the author does not understand physics. pstudier 22:17, 2005 Apr 26 (UTC)

So a reactor is just a neutron source and a fissile target? That sounds like a pretty loose definition of the term... if that were the case, then Fermi invented the reactor in 1934, not 1942. (And really, since no "subcritical reactors" have ever yet been created, why use them as the baseline for our definition?) --Fastfission 22:50, 26 Apr 2005 (UTC)
Well, a chemical reactor is just a vessel used to carry out chemical reactions, so it seems natural to call the analogous thing a nuclear reactor. It's not a nuclear fission reactor (in any significant way), although a plutonium-based RTG is fission-based even though there are no significant chain reactions.
Maybe we should have a stricter definition, but remember that there aren't any chain reactions or any fission in a fusion reactor (whether a tokamak, an inertial confinement machine, or a Farnsworth-Hirsch fusor). Granted, this article is not about those, but they are called nuclear reactors. On the other hand, giant particle accelerators used for making new elements are not usually called nuclear reactors...
Anyway, whether to call it a nuclear reactor or not is not very relevant.
The real question we should sort out is whether David Hahn actually produced any significant neutron activation. He should have been able to tell; simply (say) exposing a piece of aluminum to the output of his "neutron gun" and then measuring the induced radioactivity would be enough.
I don't think simple aging of the thorium is sufficient to account for the high (and increasing) levels of radioactivity - after all, the thorium was from gas mantles, and if that was the only effect, his levels of radioactivity should not have increased much faster than those of the gas mantles (which people habitually store for years).
On the other hand, many of the produced neutrons will have hit non-thorium and non-uranium atoms, activating them.
What's more, he had a lot of radium, initially mostly shut up in the lead box, but I imagine he tracked it (and other radioactives) around a lot. This is almost certainly why "radiation could be detected as far away as the neighbors' house".
Let's do a calculation: 10 g of radium, say, is 370 GBq, mostly alphas. That's about 10 million neutrons/sec (using the beryllium number above). Multiply by 2.5 million seconds (about a month) and that's 2.5x10^13 neutrons. If they all made U-233, that would be 2.5\times 10^13 \times \ln 2 / (159200\times 3.16\times 10^7) = 3 decays per second. So the radioactivity certainly wasn't due to U-233 (or U-238, which has an even longer half-life). Whether you consider 10 ng of U-233 a significant quantity or not is up to you.
I can't find a reference for that 30/million number, but one page on neutron generators claims that isotopic neutron generators are suitable for neutron fluxes < 10^8 per second, so it's quite plausible. There are many pages describing experiments inducing measurable radioactivity from isotopic sources, such as this one describing a class demonstration, and this one describing irradiated dimes.
So I think we can say:
  • He did generate neutrons
  • He generated tiny amounts of fissile materials
  • He produced some radioactivity by neutron activation
  • He spread radioactive contamination all over the place
What the article should actually say is up for debate. --Andrew 08:02, Apr 27, 2005 (UTC)
10 grams of radium would have killed him. IIRC, at 1 meter, this would be a dose of 10,000 mR/hr. 30 hours near this would have made him sick. In contrast, a radium alarm clock on Ebay was claimed to have 0.6mR/hr on the faceplate, which would probably be about 0.006mR/hr at one meter. More importantly, by your calculations, the induced radioactivity was 3 decays per second compared to 370 billion decays per second, or one hundred billionth of the source. This is not significant!
I was trying to get an upper bound. He did find a bottle of radium paint in an old clock, which is how he got so much. How do you get 10,000 mR/hr at 1 meter? Radium yields mostly alphas, which are easily stopped; plus he knew enough to put the stuff in a lead box.
From [3] we find that the daughter Pb-214 has a 0.25Mev gamma, and Bi-214 has a 1.5Mev gamma. This source also mentions the use of sealed sources for cancer treatment. I can't find a reference for 1,000 mR/hr at 1 meter for 1 gram of radium. Note that 1 gram of radium is about 1 curie. [4] gives the value of 370mR/hr for Cs-137, whose daughter has a 0.66Mev gamma, so I claim my figure is plausible. pstudier 21:02, 2005 Apr 27 (UTC)
The induced radioactivity was probably not alpha particles, but you're probably right that it was negligible compared to what he started with. --Andrew 19:11, Apr 27, 2005 (UTC)
From the decay chain one finds that old thorium will have 10 times the number of decays per second as pure Th-232. Very approximately, 6 year old thorium will have about 5 times the number of decays per second as fresh.
The thorium he got was likely to be old, but it's probably a factor. --Andrew 19:11, Apr 27, 2005 (UTC)
Usually, the definition of reactor includes a significant amount of reaction. Changing a few atoms doesn't count, IMHO. Therefore I am reverting. pstudier 18:33, 2005 Apr 27 (UTC)
Hmm, fair enough. I might go in and edit it a bit, but I won't try to claim it was a reactor. --Andrew 19:11, Apr 27, 2005 (UTC)

I would be much more comfortable disagreeing with the Harper's article if we could find a reference to support our claims. --Andrew 19:11, Apr 27, 2005 (UTC)

Ha... 10g of radium? That's was about the world supply of the stuff, isolated, in 1920... remember that Madame Curie had to have an international fundraiser to buy her own gram! --Fastfission 03:38, 28 Apr 2005 (UTC)
Didn't David Hahn get in the Us Navy's nuclear power program for that stunt?

Edit: Crap. I forgot my sig, again. --Admiral Roo 11:43, Jun 16, 2005 (UTC)

Shouldn't this section be moved to an entirely different article? David Hahn's reactor doesn't belong in the *definition* of a nuclear reactor - it is simply a cute story about a young kid who created something like a nuclear reactor. It is a famous story and is worth an article, but it doesn't belong in here, IMO. --Goodkarma 00:54, 14 October 2005 (UTC)


I agree. Be brave and do it! DV8 2XL 03:07, 14 October 2005 (UTC)
Sure. Merge with the David Hahn article. Simesa 13:06, 14 October 2005 (UTC)


I removed the section, the David Hahn article covers the topic in enought detail.

The radioactive Boy Scout

In 1995, a 17-year-old Boy Scout named David Hahn attempted to build a small nuclear reactor in a potting shed in his back yard. This reactor was far too small to be critical, but it included a neutron source and moderator. He collected sufficient quantities of radioactive materials that the US EPA had to be called in to saw up and dispose of the entire potting shed in a radioactive waste dump. David's parents had already secretly disposed of some of the most dangerous material by throwing it in the garbage. The reactor was built with radium (from old paint) and americium (from smoke detectors) as sources of alpha particles, which struck aluminum and beryllium to produce fast neutrons. The resulting neutrons were used to irradiate thorium (from gas mantles) and uranium (obtained as samples from a Czech company). The required information to obtain the elements and design the reactor were obtained by the simple expedient of writing letters to various organizations, claiming to be working on a merit badge or as "Professor Hahn" teaching a high-school physics class. The event received little publicity at the time but was investigated and written up three years later in The Radioactive Boy Scout, a Harper's Weekly article by Ken Silverstein (who also wrote a book of the same title; see below). In 2003, Eagle and Eagle Television, a UK production company, did a show about David and his exploits called "The Nuclear Boy Scout." The show has aired a few times on UK Channel 4.

Moved by DV8 2XL 18:39, 14 October 2005 (UTC)

[edit] US Navy clean

"The first organization to develop utilitarian nuclear power, the U.S. Navy, is the only organization worldwide with a totally clean record. "

Do we have any references for this, because it's open to some interpretation. What do we mean by "totally clean"? Never had a radiation leak? Also the British Navy has a pretty good reactor safety record. DJ Clayworth 21:38, 26 Apr 2005 (UTC)

This certainly does seem to be too strong an absolute, even for giant organizations. Has EdF had a severe accident? The Germans? The Japanese have had problems with their breeders and reprocessing plant, but I know of no other problems with their normal plants. I'd support a wording change to "The first organization to develop utilitarian nuclear power, the U.S. Navy, conspicuously has had a totally clean record." Simesa 16:22, 10 August 2005 (UTC)
In 2002 or 2003 the nuclear power plants that supplied power to much of Japan were found to have cracks, and other damage that had not been properly reported or fixed, which led to their shutdown. This caused an energy crisis in Japan. I agree with the wording change though. --Ignignot 13:26, August 11, 2005 (UTC)

[edit] Cancellation of US plants by year

This information was requested in a note in the article. As can be seen from the data, significant numbers of cancellations had started even before Three Mile Island (1979). After Chernobyl (1986) few plants were cancelled.
Plants cancelled by year [5]:
1974 - 5 1975 - 6 1976 - 1 1977 - 7 1978 - 8 1979 - 4 1980 - 15 1981 - 10 1982 - 14 1983 - 6 1984 - 6 1985 - 2 1986 - 2 1987 - 0 1988 - 1 1989 - 0 1990 - 1 1991 - 0 1992 - 0 1993 - 0 1994 - 1 1995 - 2
3 TVA plants haven't officially been cancelled even yet
Simesa 15:54, 10 August 2005 (UTC)

[edit] Image deleted

Image Image:AKW-LeibstadtCH.jpg was apparently deleted by user:Mel Etitis - anyone know why? Simesa 11:40, 18 September 2005 (UTC)

I see that the image was deleted due to no source info being entered and thus being a possible copyvio. I tracked back to the original entry, and it was in early May by an anon user - I've left a message on their talk page. I've written to NEI for a photo we can use. Simesa 12:29, 18 September 2005 (UTC)

There are many photographs of nuclear reactors available for free, so there's no reason to use a suspiciously sourced one. Ones already in use include Image:Nuclear_Power_Plant_Cattenom.jpg and Image:Three Mile Island (color).jpg (a decent picture of a reactor, though using a pic of TMI might be bad judgment for a page on reactors). I'm sure there are many others available in the public domain if we search around a bit; pictures of reactors from a distance are usually not hard to get. --Fastfission 16:04, 18 September 2005 (UTC)

There are a ton of images on Commons as well. Take your pick! --Fastfission 16:07, 18 September 2005 (UTC)

Thank you for Commons - I hadn't used it before. Simesa 17:53, 18 September 2005 (UTC)

[edit] Break nuclear power controversy into its own article

Is there anyone else out there that thinks that there should be an article devoted to the "nuclear power controversy"? This has been done with other aticles as well and really helps to clean them up. I am proposing that we do this because currently, on many nuclear powerplant related articles the same arguments against nuclear power are listed over and over again. Also, it reads poorly to have things like

"Currently all commercial nuclear reactors are based on nuclear fission, and are considered problematic by some for their safety and health risks. Conversely, some consider nuclear power to be a safe and pollution-free"

in the opening paragraph. The article is supposed to be about nuclear reactors, not the controversy. By inserting the controversy for every nuclear article, we lose conciseness. I don't want to look like a nuclear proponent here (although I am), but take a look at evolution and how they introduce the controversy page.

This "problem" happens way to frequently in the nuclear articles and is messing them up, lets move the controversy to its own page so the articles read like an encyclopedia entry and don't read like arguments. Nuclear power is a technology, and as such, it should be defined like one, let the politics have there own page. I'm not saying we ignore the nuclear opponents, this will actually give us a more standerdized and, I think, fairer way of covering the arguments.Lcolson 19:31, 17 December 2005 (UTC)

I agree. We should mention the controversy where appropriate but it should not get in the way of explaining what anuclear reactor actually is. I have noticed similar things in pebble bed reactor, list of nuclear accidents, and its children. --Ignignot 19:35, 17 December 2005 (UTC)
Agree agree. zowie 00:04, 21 December 2005 (UTC)

[edit] Attempt at NPOV

Some experts predict that electricity shortages, fossil fuel price increases and concern over Greenhouse gas emissions will renew the demand for nuclear power plants. Watts Bar 1, which came on-line in 1997, was the last U.S. commercial nuclear reactor to go on-line.

As of 2004, the immediate future of the industry in many countries still appeared uncertain,...

As the introduction to the section on The future of the industry, that's both US-centric and extremely misleading. As the section already later (grudgingly? and unclearly) admitted, there has been little if any hesitation, ever, on the part of most other countries in adopting this technology. That's not to say that there have been no demonstrations! There has been political activity everywhere. But only in the USA, the Philippines and parts of Europe has it been successful.

Despite my admitted POV (green and pro-nuclear, both for >40 years) on this I think something needed to be done. That sort of political spin is I would hope embarrassing to all Wikipedians.

(IMO the export of expensive Western politics to the economically defenceless Philippines at a cricial time in the development of their democracy will one day be seen as one of the saddest developments of the entire 20th century. But that's another story! I think we agree on one thing: Whoever was to blame, the story of Bataan Nuclear Power Plant is quite tragic.)

The phrasing is still not entirely consistent, and I'm not altogether happy with still starting the section with the US perspective, but it is IMO the most frequently quoted worldwide by both sides so perhaps it's not inappropriate if properly identified as a US perspective. Andrewa 16:16, 1 February 2006 (UTC)

Something that still needs fixing: The second paragraph still reads as though the PBMR is a third alternative to thermal and fast neutron technology. This is not true of course; The PBMR is a gas-cooled, graphite-moderated thermal reactor with the neutron moderator integral with the fuel elements. Andrewa 16:22, 1 February 2006 (UTC)

[edit] Fuel quantity

How much fuel is in a fission reactor? I have heard up to 100tons of uranium, but that seems a bit much. Is it linked to the chance of nuclear meltdown? Could someone please edit this into the article, and include a credible source? Thankyou :) - Jak (talk) 14:53, 16 July 2006 (UTC)

[edit] Waste storage above ground

I have removed this request by an IP poster from the article text for consideration here: “Storing high level nuclear waste above ground for a century or so is considered appropriate by many scientists. Someone who knows what this means, please clarify.” Moonraker88 18:20, 15 August 2006 (UTC)

[edit] Clarification / Rewrite?

192.235.8.4 changed a paragraph to read "Pressure vessels holding steam heated by the reactor are used by most commercial and naval reactors. The pressure vessel serves to balance out pressure transients in the primary loops which occur with reactor power changes. The pressure vessel also serves a small role as a primary coolant make-up source. The pressure vessel is almost always lined up to the reactor and is only isolated from the reactor for special maintenance or testing." This paragraph is confusiong to me, a nuclear engineer -- normally the RPV (reactor pressure vessel) is the "pot": 192-235.8.4 seems to be confusing the pressure vessel hull of a submarine with the RPV. I'm not sure how a steel pressure vessel serves as a coolant makeup source. Without unilaterally rewriting this text, would others care to comment? Simesa 21:25, 21 November 2006 (UTC)


This is talking about a Pressurizer vessel, used on PWR type reactors. 204.96.197.19 22:17, 10 January 2007 (UTC)Kyle Kennett

[edit] MYRRHA

Recently an unregistered user requested the creation of an article on this reactor in development. Please feel free to discuss the issue here and incorporate relative information into the Nuclear reactor article. I have very little knowledge of reactors and would not be able to contribute much to the article. - cgilbert(talk|contribs) 02:47, 27 January 2007 (UTC)

[edit] Risks to Humans section

User:Uruiamme clearly does not now how to write for an encyclopedia and does not seem to understand Wikipedia's content policies. While a section on risks to humans is clearly important and probably needed, the current one is a mixture of uncited assertions, personal disgressions, unencyclopedic style ("I must interject" -- hello?), etc. I have removed the section and put it below. Someone with a better understanding of how to write for an encyclopedia is encouraged to re-write it. --24.147.86.187 17:46, 24 February 2007 (UTC)


[edit] Risks to Humans

A nuclear reactor is an extremely complex device. Depending on the design, there are certain risks that a reactor plant could be damaged by some accident, and subsequently, spread this damage to the surrounding environment. Such an accident is called loss of containment. The effects to people in the vicinity might be exposure to a number of different health risks, including:

  • radiation: Gamma radiation or neutron radiation can be deadly, especially during a power excursion that exceeds a plant's design.
  • high temperatures: Nuclear reactors operate far above room temperature even on a normal basis.
  • mechanical havoc: the destruction of a reactor, as containment vessels are breached, is violent enough to cause explosive effects.
  • steam: Water and steam are normally contained around a reactor, the release of which can be deadly.
  • fires: The heat and the smoke of any fire can be deadly.
  • direct contamination: The presence of nuclear isotopes on a person's body or clothing, which give off alpha, beta, and gamma rays, is contamination. Plant workers might be contaminated during an accident.
  • indirect contamination: If nuclear isotopes fall from the sky from a burning or damaged reactor plant, the contamination is the result of "fallout." Indirect contamination could occur at any time, even thousands of years after an accident!
  • exposure to radioactive gases: Many fission products happen to be gaseous and can be breathed.
  • consumption of contaminated food: Contaminated birds, animals, fish, crops, water, and milk pose a health risk if consumed.
  • long-term, chronic effects from any of the above, such as radiation sickness, leukemia, or cancer.

[edit] Known Fatalities

Of course, nuclear reactors have been operating successfully since the 1940s, and accidents which have led to the death of people are rare. A single death occurred in 1958 at a research reactor in Vinca, Yugoslavia. In 1983, there was a single fatality at the RA-2 research reactor facility in Argentina. There has really only been one widespread nuclear catastrophe in the civilian power industry, the Chernobyl disaster of 1986. It led to the death of 56 people, according the sources cited by that Wikipedia article. I must interject that the RBMK reactor used at Chernobyl was designed to be able to acquire weapons-grade plutonium, even retrieving and refueling the reactor while operating. In other words, its design offered a military advantage and suffered from numerous safety disadvantages. Its design is extremely unwise. See civilian nuclear accidents

As for the military, both the US Army and the Soviet Navy have encountered fatal nuclear mishaps while operating reactors. In the US Army's single fatal accident, the SL-1 reactor near Idaho Falls, Idaho was destroyed in 1961 during a shutdown maintenance activity. All three personnel on site were killed when the reactor's central control rod was manually pulled out too far. The US Army no longer operates any reactors. The Soviet Navy, however, had a long history of repeated accidents and failures. Contrast this to the US Navy, which has never had a major nuclear accident of any kind.

For a list of military nuclear reactor incidents, see List of military nuclear accidents (although this describes problems with nuclear warheads, nuclear fissile material, and nuclear waste, too), Database of radiological incidents and related events, and WISE - Nuclear issues information service. There you will find descriptions of the Soviet's K-8 sub (high radiation doses), K-19 submarine (fourteen total deaths), the Icebreaker_Lenin (thirty estimated deaths), the K-27 sub (nine deaths), the K-314 submarine (ten deaths), and other non-fatal accidents.

In all subjectivity, besides Soviet-designed reactor plants, there appears to be a very small casualty rate amongst nuclear reactor plants in the last sixty years (five). This is a volatile subject, however, since in most cases there is a tendency to lump reactor plant incidents with other radiological incidents, as seen in the websites above. With thousands of reactor plant years in operation, the designs of the civilian nuclear power industry in the West have a good track record of being safe. This includes dominant nuclear reactor designs in Canada, France, Germany, Great Britain, Japan, Switzerland, and the United States. The designs utilized in the West typically include a heavy emphasis on safety, containment, and emergency systems. None of these countries have suffered a human casualty in any commercial reactor plant due to a reactor accident.

[edit] Industrial and Radiological Health Hazards of the Fuel Cycle

But to the great discredit of even the best designed reactor plants, there are still enormous issues regarding the acquisition, installation, removal, and processing of the fissile material required for operating all of these "safe" reactors. Nuclear waste is a "hot" topic, for health and safety reasons. It used to be that even the most conscientious of nuclear programs would overlook the need to effectively dispose of waste nuclear materials. The US Navy used to release their radioactive resin and other wastes into the open ocean, saying to the world, "Dilution is the Solution to Pollution." While true to some extent, this 1950s ideology is not going to last much longer. I think even the Navy got tired of issues in which radiation alarms would be set off by submarines with leaky valves and contaminated hulls, so they voluntarily stopped their waste discharge practices in the 1970s<citation needed>.

To start a reactor out fresh, it needs fuel. It takes literally months or years for the raw uranium to be mined, processed into LEU/HEU (if necessary), combined with oxygen (for U2O), and formed into pellets. There are often nuclear poisons mixed in, too. By the time the fuel is pelletized and ready, it usually has to be inserted into special fuel cell components, as mandated by the design. This must all be done with careful regard to criticality and radiation levels of the people performing this manufacture. This can all be dangerous work, especially the mining of the raw uranium and the enrichment process.

Once nuclear fuel is spent, it must be removed from a reactor core and disposed. If you thought being careful with new fuel is imperative, try to be even more careful with spent fuel! Fission products are practically laden with radioactive elements of all kinds. The radiation level of spent fuel is so enormous, that it is essentially the last thing in the world anyone would ever steal. Many refueling operations allow for a temporary "cooling off" period in which the spent fuel containers are allowed to remain submerged in a pool of water to help remove heat and to maintain a radiation barrier. However, temporary storage of spent fuel is becoming permanent in many reactor facilities due to the fact that few are prepared to process the spent fuel. It is extremely expensive, life-threatening, and challenging to handle and dispose of spent fuel. A lot of this must be done by robotics and machines and cranes and lead-lined boxes.

Where does all of the high level waste go? More often than not, it goes nowhere, literally. Most plants have to keep their spent fuel. Low-level waste is challenging enough, but it can be processed safely.

So although the operation of most nuclear reactor plants can be shown to be extremely well-organized, well-designed, and well-maintained, we must also consider the offshoots, or the sidelines, which require similar vigilance and attention to detail. A lot of focus is placed on the reactor plant itself, but what about the guy who mines uranium? What about the researcher who handles small amounts of fissile material? Is the crane operator in charge of refueling the reactor plant trained to handle fissile material? Will he cause the safest reactor in the world to meltdown by moving the fuel too sloppy? These issues are just as important to the safety of the public as the operation of the reactor itself.

Retrieved from "http://en.wikipedia.org../../../n/u/c/Talk%7ENuclear_reactor_ca04.html"