K.Takeshita wrote: > On 11/25/06 6:57 PM, "Adam Maas", <[EMAIL PROTECTED]> wrote: > > >>The solution to the environmental issue is to outlaw coal power and push >>through nukes (Which are very safe and the disposal issue for spent fuel >>is far less of an actual issue than anti-nuke luddites insist that it is). > > > Let me chime in on this OT :-). > Before immigrating to Canada, I worked for the power reactor programmes in > Japan for many years. > > 1. The coal burning plants are generally bad but the ones of latest > technologies significantly reduced the emission level (i.e., fairly clean > burning). But generally in North America, let alone here in Ontario, fossil > fueled plants are old and worst polluters (and possibly much lower thermal > efficiencies, lower than that of very vehicles they will be charging). If > many cars become electric and start using grid power, it would be a huge > demand, and environmental or the efficiency concerns all come back to those > of the power plants. > > 2. Re nuclear (sometimes termed "unclear" :-), it does not burn anything and > the fuel is more abundant (power density is extremely high). Country like > Japan has no choice but going nuclear which they are. > The problem is the cost. It is designed and built against almost unreal > safety criteria which is making the cost of nuclear power plants billions of > dollars/plant, requiring 7 to 10 years lead time to complete. This is > because of public pressure for the environment/safety, often undue, unfair > and unscientific, > I can give you two easy-to-understand examples. > > A). One of the most feared accidents is the break of piping in the primary > steam loop (radioactive). Design criteria is that the pipe break always has > to be the clean guillotine break (total circumferential cut) which occurs > only in theory. On top of that, once the guillotine break occurs, the pipe > ends wildly dance around (pipe whip) and break other piping and structures. > Therefore, all these pipes, some of them are really large, have to be > restrained by big anchors, which are very expensive. > > B). The 2ndary containment structure (usually a dome type concrete structure > you see from outside) which contains the primary containment which is a > massive steel enclosure, has to be designed to withstand an unobstructed > crash of a commercial jet liner directly hitting the containment structure., > That's why the thickness of the concrete is usually in metres, with tons of > reinforcing bars, which again is extremely expensive structure. > Now, what the real probability of a commercial jet liner flying directly > over a nuke plant, somehow gets into trouble and makes a direct hit on the > structure. There is a figure for that probability (Rasmussen Report) but it > is on the order of the one over several million (or probably much less, I do > not remember). > > These are just two simplified examples but our life would be so much easier > if the cost of nuke plants could be reduced significantly (but reasonably). > There is always a variety of different level of risks in any industrial > products but nuke plants IMO are very safe. Usually, failure occurs in > conventional part, not radioactive part. But it is very difficult to > properly educate and have them understand the general public about the nuke > plant safety. Unfortunately, their often unfounded fear must be justified > in our life time. It is always psychologically tied to nuke bomb. > It is also like an airplane crash. It seldom happens but when it does, the > consequence is usually devastating. But the possibility of the China > Syndrome type catastrophic failure of a nuke plant is almost none.
The (at least) two that we've already had don't count, then? I know farmers in Wales still affected after Chernobyl, twenty years ago. Nor the fire in the graphite core at Windscale that spread radioactive particles over most of western England? It's not the frequency that matters, it's the magnitude. > > In any case, the fully electric vehicles have to be evaluated in terms of > true power source, the power plants, its environmental impact and the > efficiency etc. > > Ken > > -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
