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On Overheated rods & rhetoric

Wayne, I am not an expert on steam generators, but I would refer you to Meredith Angwin's excellent piece on the matter, "San Onofre and Steam Generator Design." Meredith covers the topic in far greater detail than I could hope to.

On Overheated rods & rhetoric

The events to produce a serious radiological release at a spent fuel pool would require a combination of several very unlikely circumstances. First, for any spent fuel pool at ground level, generally it is difficult to conceive of a scenario where the integrity of the pool itself is compromised; that is, as long as it is capable of holding water, the remediation is simply to refill the pool. Part of the security measures post-9/11, and those following from Fukushima, have included preparing for better ways to ensure adequate auxillary water supplies to the pools. That being said, again - there is the further issue of the fact that to a limited degree, spent fuel pools are an inescapable fact of life - fuel which has not been cooled for several years (generally at least 4-5 years) is not suitable for relocation; it must be kept under water as inventories of shorter-lived fission products decay away.

Given that, part of what has been done is to look at the accident planning and response scenarios, which both the industry and the NRC have been busy doing since the 9/11 attacks.

That being said, reprocessing - in my opinion - is a good longer-term strategy for managing spent fuel, particularly for the reasons you list. Heat is not as much of an issue for the fission products here, as the remaining fission products (which are not recycled as new fuel) are generally vitrified into glass logs (borosilicate glass - pyrex, basically) to immobilize the fission products. This of course has a much higher melt temperature (and is not at risk of spontaneous combustion), so thermal management is not much of an issue here.

On Overheated rods & rhetoric

Here's the thing - the argument you express here is a sound argument, and one I have no quarrel with. But it's not the argument the Senator or Alvarez is making.

If the argument is, "We need to clear space such that we can safely relocate fresh rods from SP4 to a more structurally sound common pool," you'll get no argument from me. This is actually a sound and reasonable argument. The problem with the argument is that older rods themselves present the risk - which clearly they do not. The problem is further compounded by folks like Alvarez pushing a broader agenda against wet storage writ large.

Again, I'm not arguing that losing the integrity of SP4 is insignificant - but 1) it's not the doomsday scenario being described, and 2) The solutions being proposed are inappropriate. I actually think TEPCO is handling the situation correctly, here, in the sense that they are applying an appropriate triage - stabilize the SFP first, move "younger" rods to a more stable location if possible, then worry about "older" rods. It's Alvarez and Senator Wyden who appear to disagree.

On Overheated rods & rhetoric

I think you've misinterpreted my position, here. I actually do think a failure in the structure of SP4 would be a very bad thing indeed, precisely for the reasons you indicate. I maintain my doubts about the zirc fire contingency, namely because outside of the freshest fuel, none of the fuel in the pool has sufficient heat to get anywhere close to this. Meanwhile, the "freshest" fuel is now a over year old - meaning the source term on the decay heat has decreased substantially. Again, I have provided my data for this, and you are free to check my assumptions. 

Meanwhile, your point about the integrity of SP4 is the reason why I've argued that maintaining the integrity of the pool is the top priority - focusing on dry storage is an unhelpful distraction when the "problem" rods are those least likely to be suitable for dry storage. Again, the issue here is priorities - if the integrity of SP4 is in doubt, this should be your first priority no matter what. Moving out older rods does little in terms of marginal gains if the pool fails.

EDIT: To emphasize a point here - assuming that SP4 is essentially a total loss (i.e., no way to triage the structure itself), one still must deal with the issue of what to do with the "young" rods. This would obviously mean that again, the focus on dry storage is largely a distraction; it's just fine for older rods (and TEPCO obviously doesn't need a non-expert like Alvarez telling them this), it's inappropriate for "young" rods, which means the driving focus still should be on what to do about these rods (such as, as has been pointed out by others, transfering them to the common storage pool). END EDIT

But going further, the main point here is that folks like Alvarez are jumping over this as a means to condemn all storage pools, something which is clearly silly at best and diverts resources from more productive safety improvements at worst. 

On Overheated rods & rhetoric

I have to wonder why you seem to be intentionally misrepresenting the argument here. 

There's nothing wrong with moving older fuel to dry storage casks - and certainly, if you want to say that we should get the older fuel out of the pool due to concerns over stability, fine. But the "younger" fuel generally is going to have to stay parked for awhile - which means that keeping the structural stability of the pool should be the absolute highest priority. Which, it would seem, is what TEPCO is in fact doing. 

The point here is that by the marginal gains from prioritizing dry storage for older fuel are a lot smaller than the issues surrounding the "younger" fuel. Again, not a difficult argument here - the issue here is in priorities. 

On Overheated rods & rhetoric

I can't help but feel as if you've missed the broader point here. Spent fuel that is relatively "young" cannot be relocated to dry storage. This means that it has to stay in the pool until it's cooler - which means maintaining the integrity of the pool itself is the top priority. "Older" fuel generally isn't going to be susceptible to the kinds of problems which would lead to widespread release, like melting or cladding rupture. In that sense then, worrying about pulling it out of the pool is a misplaced priority. Again, the priority here is to maintain the integrity of the pool such that the "younger" fuel remains cool. Full stop.

Further, there's the issue of just "what" is going to happen if the spent fuel pool fails. Again, you seem to blithely ignore this issue. Yes, it will be a problem, but the so-called "experts" here have failed time and time again to demonstrate any plausible mechanism by which this would produce the catastrophe they predict. To emphasize - a failure of the spent fuel pool would be very bad indeed and all reasonable precautions should be taken to avoid this contingency, but it is not nearly the kind of catastrophe being predicted.

Finally, I must wonder if you sneer at the idea of other credentialed experts. Do you seek out someone who is not a physician and has no medical background to diagnose a medical problem? Why in the world then are we supposed to be trusting the demonstrably incorrect assesments then of someone with no relevant technical credentials? Again, it's not simply a matter of credentials here - it's the fact that these arguments can very easily be demonstrated to be factually incorrect, while being given by someone who has no relevant background in the topic.

On New nuclear era begins after approval of Vogtle plant – but questions remain

No offense intended, but I don't think Mr. Pierobon has looked at the issue terribly closely if these are the issues he is defining as "open questions" - instead it sounds a lot like concern trolling.

For one, the AP1000 design is designed around numerous "passive safety" features, not the least of which is cooling by natural circulation - obviating much of the concern which existed for the older-generation technology present in the GE Mark-4 units present at Fukushima. This explicitly does not rely on the types of electrical systems which failed at Fukushima, leading to the partial core melt. Second, despite Chairman Jazcko's dissent, the four remaining NRC commissioners found that the AP1000 design specifically addressed the safety issues presented by the Fukushima disaster - see Dan Yurman's coverage of this for more detail.

With respect to the waste issue, this topic has been getting explicit attention by the Blue Ribbon Commission. To emphasize - spent nuclear fuel is not a technical problem, as technical solutions clearly exist, as evinced by both France and Japan. The problems are inherently political - something which the Blue Ribbon Commission's findings had numerous recommendations for. To wit - our options are not simply limited to "keep it at reactors or dump it in a very deep hole in the ground."

Finally, as pointed out above, uranium supplies are neither mostly from FSU states nor are they particularly in jeopardy, given abundant uranium resources found in friendly countries including Canada and Australia.

Again, these are not exactly questions to which little effort has been expended to answer. Ignoring this body of effort in service of a rhetorical question severely undermines the point being made.

On An IAEA perspective on Fukushima

Good observation, Nathan. I haven't had a chance to follow-up with my source, but that may have just been a typo in the talk; 300 kg seems like a more believable number, in retrospect.