Fukushima 2 months on

[LCHIEN]

Well its been two months on and coverage has died down to a large extent.

They just announced that they have discovered that a major melt of the fuel rods had occurred in reactor 1 and probably in 2 and 3 within 5 hours of the Tsunami. Pools of molten fuel pellets were in the bottom of the primary reactor containment vessel and likely burned a hole in the bottom of the RCV leading to the persistent leaks of radiation.

Its not really a surprise to me, how can you pump water for 2 months with fire trucks and still not be full? Unless you have big leaks.

The "9 month" plan now seems in real jeopardy. We'll see what they say in a few days.

Quick poll to find out how this forum views nuclear power

my views:
this is a tough subject.
Clearly there's more dangers than I believed 3 months ago.
Need better backup systems and emergency plans
Probably should pan to shut down all plants needing active cooling and phase in plants with passive cooling.
Need to put spent fuel in dry casks, not pool storage
better security
Worries about plants in third world countries who would worry more about costs than impact on the rest of the world, & tend to have less well trained and regulated plants.
Still may be a better alternative than coal and NG fired plants.
Many of these requriements take BIG bucks.

[180x]

LCHIEN,

Fuel damage was a foregone conclusion by many in the industry, although the utility would not admit to it until there was concrete evidence. No surprise there.

There doesn't necessarily have to be a "big leak" (although I'm not disagreeing with it) for the Rx vessel/SFP (spent fuel pools) inability to stay full. Remember spent nuclear fuel continues to generate a lot. Unlike a fire, you can't just spray it with water to put it out. If there is no to way provide heat removal from the water, it will boil/flash to steam/evaporate. There will always be a need for SFP for storage until they discontinue producing so much thermal heat to be able to be placed in dry storage.

There are 104 active units in the US currently; with all have active emergency core cooling systems. There are only two plants building two units apiece currently under construction with passive ECCS. It will be a long time before the generation lost through decommissioning these 104 units can be replaced. The nuclear industry in the US actually does a pretty good job of being proactive in its pursuit of nuclear safety and efficient operation.

If you would expound a little bit more when you state a desire for better emergency plans and security?

[JimD]

There will be some changes but exactly what is being determined. I think it is likely there will be generators to charge the batteries under station blackout. There is already a new request - probably on it's way to becoming a requirement - for U. S. utilities to know their time to near boiling temperature in the spent fuel pit. That is some calculations which we have not been doing but will not take a large effort to do. Knowing this time will help utilities make changes to make the time longer. I've heard nothing about putting in piping to provide a way to refill spent fuel pits from outside but I would be surprised if it does not happen. That would avoid fire trucks and other creative ways to crudely try and fill the spent fuel pit as it evaporates and boils off.

Basically I think we need to have more margin to withstand a longer time without offsite power and at least have some plans to deal with beyond design basis events. I doubt the costs will be huge because the risk is not very big.

I did not vote only because my choice is not an alternative. I think we need to continue to operate all the nuclear plants we have - with minor changes as the industry or regulator deem prudent - and build new ones. I am also in favor of moving fuel more quickly to dry storage. That is also a feature of AP1000s, by the way. They have a comparitively small spent fuel pool so you can only store fuel long enough to let it cool down and then you have to go to dry storage. Currently utilities wait for their pits to get full. I suspect that will change. But there are practical issues of there only being a certain capacity to build dry storage casks. And needing to recover the cost from rate payers. But timetables for dry storage projects and the speed of loading casks for plants already doing dry storage are both likely to speed up.

Jim

[LCHIEN]

Jim - your choice was the last one on the list, I think. Maybe I shouldn't have mentioned the fossil fuels bit, it's immaterial the reaosn behind that choice, I suppose.

[cwsmith]

I voted shut down the old ones and build safer new ones.

But, I have a problem with the technology and the engineering thought behind the older plants; and, I'm not sure what the new designs would be and if they've envisioned

I think Loring worded it for me, with his, "Probably should plan to shut down all plants needing active cooling and phase in plants with passive cooling."

The existing designs just don't seem very logical to me. Why would anyone build a Nuclear plant that required power to keep the rods cool, and why in the world would you store the spent fuel rods in an elevated position anywhere near, much less over the reator?

Seems to me, that if the conditions occur where it's necessary to "scram" a reactor, there may be a good possibility that power to the cooling pumps may also be in jeopardy. Perhaps my thinking is too simple, but using a technology, that requires a sophisticated, powered cooling technology to keep it safe, even after it's shut down, is simply flawed thinking IMO.

One watches a program like the much acclaimed, "Life after Humans" (I think that was the name of it), and I now see that it was seriously flawed. They talked about how a city like New York would flood after several months because humans wouldn't be there to maintain the pumps that presently keep the water out of the foundations and the subway and underground systems. Also mentioned was how Hoover Dam's generators would eventually shut down as the filters clogged with algae and other debris. But I didn't see anything about all the reactors melting down, because of the loss of power to the cooling pumps!

One can only imagine the catastrophic effects as one Nuclear facility after another melted down... the planet would soon look like it went through a nuclear war! (It's sort of like discovering a power that would accelerate a train, but you need "fuel" for the brakes to work... and not thinking about what happens when you run out of fuel.)

How in the world does one engineer such things... overconfidence or just blind to the possibilities?

CWS

[dbhost]

I am incredibly torn over this one. While there are certainly huge benefits to Nuclear energy, there are also insane risks. And the question always comes up, what to do with the waste...

I think that Nuclear power is one of those areas of scientific and commercial endeavor where I think as a society we really need to ask ourselves, just because we CAN do a certain thing, that still doesn't answer the question of SHOULD we do this thing...

We are such an energy dependent society, and the emerging economies of the world are getting hungrier and hungrier for energy as well. To remove Nuclear power from the mix of things would be disasterous from an economic, and even environmental stand point as power generators would be forced to use more and more fossil fuels to make up the demand for power. However leaving nuclear power online and operating would leave us globally at risk for another Three Mile Island, Chernobyl, or Fukushima type accident. And with the slow down / stopping of production of various Japanese companies, that many American companies depend on as suppliers, we are already having substantial hits to our already staggering economic recovery...

I fear that the Nuclear genie is well out of the bottle. And at this point, our best hope is to find better ways to manage / prepare for the disasters that will come. We could in the industrialized nations certainly eliminate our usage of nuclear energy as Germany is trying to do, but that does nothing over regimes such as Iran and North Korea with their emerging Nuclear programs. Even IF those programs are for peaceful purposes, I can almost guarantee they will not be implemented with the same amount of concern for safety as say the U.S., Japan, or Western Europe. So I think our best hope is to contain what WE can far as implementing better, more passive safety systems and encouraging other nations to do the same... The idea of eliminating all nuclear power globally I just think is a pipe dream. Maybe a noble one, but a pipe dream no less...

[woodturner]

While there are certainly huge benefits to Nuclear energy, there are also insane risks.

I'm not seeing "insane" risks at all. With fossil fuel plants, I can see your point - they can cause extreme damage to the environment - but the risks of nuclear plants are much less and are vastly overstated by the media and misunderstood by the public.

Everyone seems to fear "the China Syndrome" but doesn't understand that it's a fictional scenario. People talk about Chernobyl and Three Mile Island, without understanding that less radiation was released than a coal fired power plant spews into the atmosphere in less than a year.

Put another way, coal fired power plants kill hundreds of people a year. Hydro power plants and windmills kill tens of people a year. Nuclear power plants have killed something in the range of 6 people in the last thirty years.

I think if people had accurate factual information, opinions would be very different. People fear nuclear power because they believe it is unsafe - and if they understand it is essentially our safest form of power generation, they would likely react differently.

[Black wallnut]

I don't like any of those options! The last one is the best IMHO however not because of the reason stated. I think we need to build more as well as do whatever is reasonable to continue to increase safety of existing plants.

[dbhost]

Eh, I never said the risks of fossil fuels aren't insane either...

As far as the number of deaths / illnesses caused by one power source or another. Perhaps you should read http://en.wikipedia.org/wiki/Chernobyl_disaster_effects

This quotes reports from the IAEA, The World Health Organization, the United Nations, and the governments of Belarus, and the Russian Federation, they pin the death toll of the Chernobyl accident at ~4,000

And I think the display from the Ukranian National Chernobyl museum says all it needs to...

[JimD]

Nuclear power has risks but the fact that the fuel is so comparitively inexpensive lets the risks be managed throughly. Not always well, but a lot of attention is paid and money is spent. Fossil fuel is compartively much more expensive so much lower levels of safety are used in the plants.

Some of the need for cooling is due to the fissions not stopping instantaneously regardless of what you do. That diminishes on an exponential scale - quickly - but these are big plants so it is initially a lot of thermal energy to be moved away from the fuel. Some of the need for cooling is just the mass of the fuel and surrounding parts of the plant. The temperatures and pressures are much lower than fossil plants but still pretty high.

Because we cannot depend on off-site power being available, plants that need active cooling have to have diesel generators. The problem is that the tsunami was much bigger than anticipated so the generators were lost an hour after the earthquake. If the diesels had been up on stilts or on the hill behind the plants, the plants should have cooled down normally and we wouldn't be talking about this. Something to make diesels less vulnerable seems like it should happen.

The nuclear industry always looks at operating experience from other plants to decide what we need to change in the plants we are responsible for. This is a bit different because the "what happened" part is still unfolding. But reviews and changes are already starting based upon the available information.

Spent fuel pits at an elevated level where the vessel head closure is located is unique to BWRs. The latest BWRs are not this way but most of the existing fleet is. I don't like that layout but it would not have had a dramatic effect if they had just kept water in the pits. All PWRs (at least in this country and the ones in other countries that are built on U. S. technology (like the French fleet)) have their spent fuel pits near ground level.

Jim

[Russianwolf]

I'll grant that the number of major incidents has been lower with nuclear plants, but the results of those incidents has been much greater.


I recently saw a program on Chornobyl where they had chronicled the clean up. The robotic vehicles that I attempted to clean up the most hazardous materials from the roofs of the structures with were not immune to the radiation levels being put out to the point that one of them final "commited suicide" by driving off the roof. A small army of men had to then go on that same roof and remove the contaminated debris. Even with strict time limits on how long they could be exposed, many of them are now suffering from severe radiation poisoning.

One Russian report pegs the number of increased deaths at nearly 1 million between 86 and 04 from the contamination.

So yes, I see major risks with Nuclear Power. And I'm one of the ones that thinks we should build better nuclear plants to get rid of fossil fuels. I'm hoping for the Fusion break-through that would decrease the risks from the Fission plants.

[sailor55330]

To me, the risks of nuclear power outweigh the positives. I am not from the industry, so I dont' have all the "factual information". What I do have is what I hear, read, research, and learn based on a variety of sources. What worries me about nuclear power is the unpredictability of our environment. For example, Fukishima was designed to withstand Tsunamis and Earthquakes, but obviously not both together, which is where the kicker lies. We can predict what a nuclear reactor will or should do given outside influences, but we can't predict what the planet will throw at it, which seems to make it very difficult to define building standards.

No current source of power is without risks, but for me nuclear power is not worth it at this time. As far as I am aware, none of the fossil fuel plants have rendered the area in which they are located uninhabitable for years due to accidents, decades, or potentially longer, unlike Chernobyl and to some extent, probably Fukashima, and was narrowly missed at 3 Mile Island. Everyone said a 3 Mile Island could never happen again, then came Chernobyl, then it was said that with the lessons learned, that scale of accident could never happen, Now Fukashima narrowly missed. It's not a matter of if there will continue to be catastrophic accidents, but when, and they will affect untold numbers.

Leave nuclear alone for now and look for a more stable source.

[JimD]

I realize it may be difficult to those who don't work in the industry but I think it is important to put Chernobyl where it belongs - in a separate category. Chernobyl was a Russian designed plant that was produced to have an unusually hard nuclear spectrum - lots of fast neutrons - so it could breed bomb material at the same time it made electricity. That caused the designers to use water for cooling but graphite for moderation. The weakness of the economy of the former Soviet Union caused the designers to omit a containment vessel. The risky plant design caused it to have a positive reactivity coefficient with temperature. In other words when it got hotter it got more reactive which made it hotter.... So it runs away if you start to lose control. Which is exactly what happened.

No plant in the U. S., South America, Canada, Western Europe or Asia has a plant like Chernoybl. No graphite moderated cores, no plants without containment. In Chernoybl the graphite fire is what dispersed the contents of the core all over. Without graphite, this cannot happen in most parts of the world. The containment of a PWR would have contained the incident, even with a graphite moderated core. So for multiple reasons, we only have to worry about incidents like Chernoybl where Russian designed reactors are. Russia and the areas they formerly controlled.

The sister unit at TMI is running right now and has since it got retrofitted after the accident. It's too soon to know for sure if sister units at Fukashima will operate again. It appears less likely because there was a lot more release but it is possible. The surrounding country side was certainly not damaged at TMI. Given the price of land in Japan, I am pretty sure they will clean up Fukashima. They are much, much different incidents than Chernoybl. Their main effect is economic. The utilities lost an asset worth billions of dollars. Health effects are relatively small. We still do not know everything on Fukashima but we know that is what happened at TMI.

I am not arguing there are not real risks, only that we need to keep in mind a little about the technologies involved so we do not get confused and think Chernoybl can happen in the U. S. (or Japan). It is just not physically possible.

Even at Chernoybl, most of the health impacts are postulated to occur from relatively low level exposure. The "science" behind such calculations is shaky at best. We know about what it takes to kill a person within a month or so of exposure. We pretty much know what the impacts are of exposures a little below this level. We do not really know the effect of much lower levels of exposure over a longer period of time. The study results are mixed to negative. Some show no effect or a slight beneficial impact of exposure. Others appear to show a negative impact. But when you see hundreds to thousands of people claimed to have been killed by Chernoybl, you need to remember they are talking about long term increased risk of cancer from relatively low exposures where the science is uncertain. The linear extrapolation used is very unlikely to understate the impact, it probably overstates it to a major degree.

Jim

[leehljp]

Jim,

That was a great explanation and I appreciate it. I was scared of a runaway Chernobyl type of reaction for Japan. As bad as it was, it did not go that far, and the reason was as you stated. The reason it did go as far as it did was as much design flaw (not heeding former tsunami levels) and cultural traits as anything else.

There was one town that remembered former tsunamis and prepared for it, but many more that did not. Fudai, Here. In a couple of the towns that were wiped away, there were old stones up the hills above those towns with warnings written in them not to build below them, but no one heeded those and most people did not know they existed. That mayor of Fudai was an unusual person and one of few real leaders to emerge that did not follow the Japanese form of "consensus" for decision making.

That said, "perception" is 99% of truth in most people's mind. ANY time there is a nuclear plant problem, the uninitiated will think Chernobyl. No way to eliminate the perception.

When you know the problems and prepare for them, things are much safer. But "perception" will always prevail in most people's mind.

[sailor55330]

"Even at Chernoybl, most of the health impacts are postulated to occur from relatively low level exposure. The "science" behind such calculations is shaky at best. We know about what it takes to kill a person within a month or so of exposure. We pretty much know what the impacts are of exposures a little below this level. We do not really know the effect of much lower levels of exposure over a longer period of time. The study results are mixed to negative. Some show no effect or a slight beneficial impact of exposure. Others appear to show a negative impact. But when you see hundreds to thousands of people claimed to have been killed by Chernoybl, you need to remember they are talking about long term increased risk of cancer from relatively low exposures where the science is uncertain. The linear extrapolation used is very unlikely to understate the impact, it probably overstates it to a major degree."

I'm sorry, I don't know how to make the quote function work, but this paragraph for me personally is scary and enough to make me think we are not ready for nuclear power. In the above paragraph, it is pointed out that hundreds to thousands of people claimed to be killed by Chernobyl. Yes, it is through long term increased risk of cancer and not immediate death, but for me, that is very closely tied. If a nuclear accident had not happened, those hundreds to thousands would probably not have been exposed to enough radiation to increase the risk of cancer. As pointed out, science is uncertain about those risks. That is cause for alarm--not the information we know, it's what we don't know.

I am not disputing that Chernobyl was much different due to design and operation than any other nuclear incidents, but there is no such thing as a good nuclear accident or even an acceptable one. Nuclear accidents have been far fewer in number, but the potential reaching effects of them is much larger than traditional sources. I do understand the benefits of nuclear power, but there are risks associated with it that are greater than other sources of power and at this time, those risks are to high for me.