I'm going to stick my neck out a little based on fragmentary information. It seems to me that the cooling problem with Japanese reactors is due to a excessive safety protocols. The logic was big earthquake => shutdown reactor. However, the auxiliary power system to cool the reactor fails. But, if the reactors had been left running wouldn't it been able to generate power that would have kept it cool?
The problem is that obsolete second generation nuclear power plants continue to operate. Third generation nuclear power plants have emergency passive cooling systems that do not need pumps in order to operate. Yes I know it is a considerable expense to mothball a good nuclear power plant that still works but nuclear power is not a technology that you can scrimp on. That is why it is better to spend the money on a brand new nuclear power plant with the latest safety features because you can't afford not to. Besides the government can always pony up the money and give the nuclear industry its upgrade bailout.
It will take many years to replace existing reactors. The point that I'm making is that with our existing units, the doctrine of "automatic shutdown" seems to me to be the immediate cause of the problems. There is no evidence that any let alone all of the Fukushima reactors were damaged be the initial earthquake/tsunami. If only one had continue to operate there would have been all the power necessary to cool all of them. It seems the contingency plan didn't take into account that a record earthquake would likely disrupt the power grid for a long time.
Let's see now we have had 30 years since the 3 Mile Island meltdown to build state of the art third generation power plants that not only could have replaced the second generation units but could have added significantly to the percentage of of our power derived from nuclear energy. And today we would be building fourth generation nuclear power plants in order to obsolete the third generation. The nuclear industry has always chanted the mantra "change is normal" yet wants to avoid the inevitable obsolesence of its own technology.
Of course this does not mean that we should immediately shut down all of our second generation nuclear power plants but these units must be phased out over a ten year time period. In the meantime temporary fixes can implemented. And of course there should be an investigation as to whether or not a nuclear power plant should continue to operate during an earthquake. It may very well be that it would have been less damaging to allow the plant to continue to operate. Also the question should be raised as to why diesel engines were allowed to be used to power the pumps since these engines do not work under water. Some sort of minature nuclear power plant or battery should have been either invented or used with the automotive industry footing the bill for the technological research.
Right now the environmentalists are having a field day in thier rally against nuclear power. Yet this does not have to be so as there is no doubt in my mind that in the future nuclear fusion energy will be called by the environmentalists "the power of the stars" and will be central to their new age dream of abundant and clean energy.
I would just add that the threat from the spent fuel pools was rather underestimated and understated. In the past, the primary threat has always been centered on the reactor core and emergency systems related to that. But containment and loss of coolant from the spent fuel pools seems to me to have been 'neglected' or atleast overlooked somewhat.
The position of the primary spent fuel pools is above the reactors in the Fukushima Daiichi units 1-4. It is not hard to imagine that structural cracking in the concrete structure of the building could have resulted in draining atleast one pool. The decay heat from the spent fuel in the pools seems to have evaporated most of the water from the others.
The spent fuel seems to have been able to get hot enough to ignite a zirconium cladding burn fed by oxygen from the air and the steam from the spent fuel pool water. Zirconium fires, like magnesium fires burn pretty hot: 3000+ degrees F.
Placing the backup generators in a protected location high above a 10m Tsunami, or in a protected water tight vault beneath ground would make sense to me.
Incredible though it seems, this whole disaster seems to have been unprecidented in its magnitude. The 9.0 magnitude quake followed almost immediately by a 10+ m Tsunami seems an utterly natural outcome givien the seismic propensities of the islands of Japan, but one that apparently was not thought possible or extremely unlikely atleast as far as these power stations are concerned. There is talk that this is a "once in a thousand year event."
-- Edited by GoogleNaut on Saturday 19th of March 2011 06:24:56 AM
Ifind that one of biggest problems is clustering so many reactors at one site. If we only had one reactor per site you would have a lot less problems keeping water in the spent fuel cooling pool for example. I suspect that was an oversight as a small team of volunteers battled problems with the other reactors. In addition the radiation from one problem prevents or hinders work on another. I understand that politically and logistically collocation has advantages but it sure increases the chances of inducing problems as well.
Yes, indeed. I don't know of any other sites that have such a dense clustering of individual reactors all connected together like this. I've heard of three units on the same parcel, but they were physically seperate.
What I do not understand is why we have not seriously considered the prospects of radiation free nuclear fusion. Project Orion nuclear pulse and the concept of the underground nuclear pulse PACER power plant have demonstrated that we can harness nuclear fusion with off the shelf technology. Yet we waste money on Tokamak technology which is always 50 years into the future and takes more energy to magnetically contain the plasma than the energy you get out of it. I know the idea of lighting off nuclear bombs sounds obscene yet a super laser ignited helium 3 thermo-nuclear bomb would produce no radiation and would be the cleanest form of energy imaginable. I know critics will whine about it violating the nuclear weapons test ban treaty but the fact remains that no one is going to spend billions of dollars on a super laser and use it as a weapon when there are cheaper ways to triggger a thermo-nuclear explosion.
Even if nuclear fission plants can be made safe there is no way that these fission plants can be built fast enough to prevent runaway global warming and the Venus like inferno. 2 fusion power plants could easily supply the entire energy needs of the United States.
