Atom bomb on wheels

[kevarc]

Dave and Overmod - thank you for your posts. My Dad Worked for Westinghouse - Bettis Atomic Power Lab outside of Pittsburgh for over 40 years. He was there from the beginning till he retired. He built reactors for many subs and was Chief Test Engineer for the 1969 Refueling of the Enterprise and then ran the office at Ingall's Shipbuilding in Pascagoula from 1970-1975. He was always fustrated with people who have no freaking clue talking about nucs. As I do.

Nucs are safe.

[jchnhtfd]

QUOTE: Originally posted by BentnoseWillie

QUOTE: Originally posted by daveklepper

Storing hydrogen in solid state takes enourmous amounts of presssure, and if the container is breached you have hydrogen gas instantly.

I was under the impression that fuel cell technology involved bonding hydrogen to another substance in a true solid to avoid pressure vessels altogether.

Did I err?

well, BW, yes -- but I can see quite easily how, so don't be upset!

The fuel cell itself is a device which takes a fuel (usually hydrogen, but it doesn't have to be) and an oxidizer (usually oxygen naturally present in the air -- but again, it doesn't have to be) and allows them to combine in such a way that, during the combination, the electrons involved in the reaction have to go through a wire, rather than just zip from atom to atom. Then you take the wire and cut it, and connect the cut ends to an electrical device (such as a light bulb, cell phone -- or electric motor) and presto! Electric power. The chemical reactions are exactly the same as if you were to burn the fuel in an engine, but they take place at a much lower temperature and the energy released shows up as electric current, rather than heat.

The 'exhaust' from a fuel cell is exactly the same compound or compounds that would be generated by the using the same fuel in an engine (OK, guys -- don't get picky; the higher temperatures in an engine do generate some side products which fuel cells don't); for a fuel cell running on hydrogen and oxygen, the 'exhaust' is water vapour.

Where the bonding of hydrogen to something (a metal) to avoid the use of pressure vessels gets involved is in the technology needed to store the hydrogen (which will later be used as a fuel). One of the approaches is to combine the hydrogen with certain metals, which produces a more or less stable group of compounds called metal hydrides, which don't have to be stored under pressure but which can be persuaded to give up the hydrogen later, fairly easily.

Metal hydride storage is quite feasible. It is also quite heavy...

Overmod, your comments on nuclear power are wonderful, as usual! As you point out, there are a number of reactor designs which have better emergency characteristics than the GE BWRs; one of my favourites has always been the CANDU design -- but I'm biased! BTW, my dad worked on the CANEL project in the 50s, which investigated nuclear power for very long range aircraft. My recollection of that reactor agrees with your description. The thing actually did fly, in a modified B-36. The B-36 was a bit of a dog anyway (even with the 4 jet engines on later models) and the weight of the reactor -- which didn't power it, just along for the ride -- made it pretty close to useless.

[88gta350]

QUOTE: Originally posted by Overmod
88gta350, would you care to comment on the recent records set by TMI unit 1 -- which should shut up many armchair critics... both of nuclear technology's reliability, and of the ex-GPU's ability to build a quality plant.

For those that don't know, in 2003 TMI Unit 1 set a world record for longest continous run by a PWR(It was Unit 2 that had the accident in '79). It was a breaker to breaker run between refuelings, which means it ran continously for about 18 months without any unplanned shutdowns. This is a relatively rare occurance in the nuclear industry, as even the smallest problems can cause SCRAMS. Keep in mind that nuclear plants need offsite power to run, so if they lose power for whatever reason, the reactor SCRAMS. A surge in the tranmission grid can trip breakers, even the smallest vibration in a pump or motor can be detected and cause a SCRAM.

In 2004 we set a site record (not sure how it relates to other plants) of about 4 REMS of exposure to site employees.

GPU sold TMI-1 in 2000 to Exelon, which is the largest operator of nuclear plants in the country. Because they have so many plants, Exelon has a huge knowledge base of experience to pull from and can implement some great best-practice policies. Of course, problems still occur, pumps and motors fail, breakers trip, valves stick, but Exelon's focus on preventative maintainance and the expeerience they have in nuclear power allows them to reduce these problems aand deal with them very effectively when they do occur. If a problem occurs, it's cause and solution is quickly distributed to every other plant in the fleet so that the problem can be looked for in those other plants, and a solution quickly applied if the problem is found/occurs.

We have our next refueling outage this fall and we are on course to have another breaker to breaker run.

The nuclear industry in general has made great strides in recent years, (and Exelon is continuoslly cited as one of the best operators in the country) but of course there are still improvements to be made. The Davis-Bessie ordeal is one example. But I would have no problem living near one of these plants, and I certainly don't have any problem working there.

As for TMI-2, that was in commercial nuclear power's infancy, and I don't think the industry had enough respect for the power they were dealing with. An unfortunate series of events came together for that accident, and young, inexperienced operators were overwhelmed. I'm confidant the lessons learned from that accident and the 25+ years of operations since, and all the training they now go through, have all but eliminated the chances of an accident like that happening again. The nuclear industry has to make sure it never gets overconfidant again.

Was that what you were looking for overmod, or did you want something else in an answer?

[BentnoseWillie]

QUOTE: Originally posted by daveklepper

Storing hydrogen in solid state takes enourmous amounts of presssure, and if the container is breached you have hydrogen gas instantly.

I was under the impression that fuel cell technology involved bonding hydrogen to another substance in a true solid to avoid pressure vessels altogether.

Did I err?

[spbed]

Yes with what the RRs used in fuel I agree that electrifaction would be the way to go. BTW when I lived in NJ I used to see 1 GG1 pulling a very, very long string of cars going along at a very quick pace![:o)][8D]

Originally posted by up829

Living nearby to MP 186 of the UPRR  Austin TX Sub

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The following is copied from: http://www.bbc.co.uk/schools/gcsebitesize/sosteacher/physics/43446.shtml

Question
Please can you explain Nuclear Fission, Chain Reactions and Nuclear reactors because i really dont understand it at all! Thanx.

Answer
The centre of the atom is made up of the nucleus. Nuclei contain around the same number of protons and neutrons, but some very large nuclei in certain isotopes have an imbalance. They often have too many neutrons, and this imbalance causes the nucleus to be unstable. These are radioactive substances, the nuclei of which often break up into two or more smaller fragments. Part of the split-up nucleus will become one or more smaller elements, while neutrons are also often released. These travel away from the split nucleus and can find their way into the nucleus of other heavy elements. This can again cause an imbalance with too many neutrons and this next nucleus will also break itself up. This again releases neutrons, which causes further nucleus-splits, and so on .

If left alone in a lump of large enough fissile material, this fission process gets out of control very rapidly. This is a nuclear fission explosion, as in nuclear bombs.

If controlled, the rate of the nuclear chain reaction can be kept at a rate producing high temperatures without explosion. This heat can be used to turn water into steam that then turns a turbine and generator, producing electricity.

Another really good link for bombs: http://people.howstuffworks.com/nuclear-bomb.htm

I was being facetious when I suggested an explosion, as the concept was absurd.

[vsmith]

Didnt we beat this topic to death with a railroad tie about a year ago, something about a renegade ex NW 2-8-8-2 with a nuclear (new-que-lear as the Prez sayz) powerplant roaming the backwood of India ? ? ?

I also remember relating the actual planned atomic engine from back in the 1950's but the dam thing would have been so heavy that most of it power output would go into just moving itself, and of course theirs the legendary "Big Joe" atomic articulated Joe Stalin commissioned which supposedly sank into the perma-frost shortly after completion.

[jchnhtfd]

QUOTE: Originally posted by zardoz

So, if two nuclear-powered-loaded coal trains (wouldn't that be ironic) were to hit head-on at 60mph, would there be sufficient force to initiate an uncontrolled fission reaction?[8D]

Reason #9 as to why this is a bad idea.

In one word: no. While a nuclear reactor on board a train (or bus, or airplane (it's been tried)) is a rather poor idea, as several of our knowledgeable posters have pointed out, it's not because it might blow up.

One needs to be rather careful with the terms; an 'uncontrolled fission reaction' could refer to a reactor 'melt down'. Whether this could happen as a result of a collision involving a reactor depends a great deal on the exact design of the reactor, it's (in my humble opinion) well off the low end of the risk scale, if only because if a reactor were damaged in a collision, it is much more likely that would be seriously disrupted by a collision, which would lower the fuel density to the point that you'd wind up with no reaction at all. However, most folks, egged on by the media and by scientists blathering outside their areas of knowledge, picture a reactor literally detonating, as in an explosion, as in mushroom cloud. And even the oldest, most obsolete reactor designs (e.g. Chernobyl) don't and can't do that. Make a terrific mess, yes. Do a lot of damage, yes. Blow up? No.

But as Overmod particularly noted, the way to go for nuclear power for railroads is via electricity.

[spbed]

Super that gave me a good chuckle! [:D][:D][:D]

Originally posted by mudchicken

Originally posted by zardoz

Living nearby to MP 186 of the UPRR  Austin TX Sub

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