Friday, September 14, 2012

Mixing it up over MOX - a wrapup from Chattanooga

Crowd at the MOX hearingTuesday's meeting in Chattanooga over the draft Supplemental Environmental Impact Statement (SEIS)  over potential plans by TVA to use MOX fuel fabricated from surplus weapons plutonium had no shortage of passion. The meeting drew a packed house of MOX supporters and professional anti-nuclear activists ("professional" in the sense that these individuals clearly make a career out of attending such hearings).

Surprisingly absent however was any evidence of nuclear zombies; while the opponents employed some degree of necromancy in their arguments, no "nuclear zombies" were spotted at the meeting. (To which I wryly observed during the meeting, "All that zombie defense training for nothing...")

For those who missed it, I did a bit of live-blogging at the ANS Nuclear Cafe as well as live-tweeting the meeting (as @sskutnik, under the tag #MOXchat - and #MOXsnark as my snarkiness level progressively increased throughout the meeting...) Meredith Angwin of Yes Vermont Yankee was following the meeting via Twitter and has already posted her thoughts; I've been a bit delayed up until now (such is the life of a professor...), but I wanted to get in my impressions from the meeting.
UTK ANS students

Strong turnout

We had an extremely healthy contingent of students in attending, both from the University of Tennessee (where we had a little over 20 overall) as well as Chattanooga State's local ANS section (as seen in the bright blue and orange shirts in many pictures). A great deal of credit for this goes to Laura Scheele, the Outreach and Public Relations director for ANS national, who coordinated with both the UTK and Chattanooga State sections as well as organizing a welcome hospitality room (always popular with students!)

Also in attendance was Suzy Hobbs-Baker of PopAtomic Studios, who put together some very cool pro-nuclear signs. (One anti-nuclear activist who wandered into the hospitality room as Suzy was putting together some of her signs before the meeting rolled her eyes and said, "You have got to be kidding." Whimsy, it would appear, is lost upon the opposition. Such a lack of whimsy of course did not stop her from helping herself to some cookies courtesy of ANS.)


No zombies, but zombie arguments

As I noted above, there was a surprising absence of zombies at the Chattanooga hearing; we speculated as to whether the budding thespians had caught wind of our plans to organize on the hearing and decided to head off to greener pastures (or at the very least, softer targets).

In a rare, refreshing display of honesty, one housewife-cum-activist (this being pretty much her own self-description: "My husband pays the bills, which allows me to do this full-time"), while reading off of a notecard of pre-prepared talking points, admitted, "I don't really understand this, but I'm going to read it anyway..." There were numerous "technical" (speaking very generously) arguments of dubious merit pertaining to MOX fuel - they could be summarized essentially as follows:

  • MOX fuel burns (thermally) hotter, so it's more dangerous
  • These reactors "weren't designed" for MOX fuel
  • MOX fuel is ill-understood and experimental
  • MOX fuel with weapons-grade plutonium behaves differently than reactor-grade plutonium
  • MOX fuel leads to much more rapid neutron embrittlement of reactor pressure vessels
Some of these arguments I've handled before, but let's go through them again. 

Thermal output


As to the thermal output - indeed plutonium does release somewhat more energy than uranium upon fission. However, the reactors are being run at the same thermal output - which is controlled the same way we control uranium-only cores: with chemical shims (like soluble boron), burnable poison rods, and control rods - all of which keep the total temperature of the reactor the same as before by controlling the rate of fission.

Reactor physics of MOX fuel


The next three arguments essential come under the same umbrella - the myth that MOX fuel is somehow new and ill-understood. MOX fuel itself has been used for decades around the world in countries that reprocess used nuclear fuel, so the idea that it's somehow ill-understood is clearly false on face. 

Beyond this, many of the opponents arguments came from half-complete understandings of how reactors work; it was particularly apparent that they were being fed cherry-picked half-truths to convey a sense of technical credibility to their arguments. For example, opponents argued that MOX fuel makes the reactor more difficult to control. In a limited sense, this is true; plutonium has about 1/3 the fraction of delayed neutrons (~0.2%) as U-235 (~0.64%). 

[Aside: In reactor theory, neutrons come in two forms - "delayed neutrons," which come from fission products or decay products (on the order of a few milliseconds to a few minutes after fission), and "prompt neutrons," which are the neutrons released at fission. Reactors are typically run as "delayed critical" - meaning that the delayed neutrons are the component which keeps the chain reaction going; the reactor is in fact subcritical (not self-sustaining) from prompt neutrons alone. The existence of delayed neutrons is what allows for a reactor to be safely controlled, namely by allowing for smooth, easily controlled changes in reactor power.]

Here's the problem with the opponents' argument; nobody is proposing to run a full core solely upon plutonium fuel. Rather, the TVA proposal would, at a maximum be looking at a 40% core of MOX fuel, ramping up from an initial loading of around 4%. Further, there is of course an ongoing trend with nuclear opponents, that somehow there is a completely non-existence of an engineering discipline. A key issue to stress here is that before any fuel assembly is loaded into a reactor, an inordinate amount of engineering work is done to know just how the fuel will behave to ensure it will be done safely. No one is simply doing engineering by the seat of their pants, contrary to the beliefs of some.

Once the argument that MOX fuel is somehow "experimental" is knocked down, opponents quickly come back with a new variant - that somehow plutonium of weapons-grade variety (i.e., with a Pu-239 content over 90%) behaves substantially differently than that of reactor grade origin (where Pu-239 is about 55-70%, with about 20-25% Pu-240).

Pu composition by reactor type

With plutonium, odd-numbered species (Pu-239, Pu-241) are "fissile," meaning they will fission with thermal neutrons (i.e., the kind which exist in a light-water reactor). Even-numbered plutonium species will not; they typically absorb neutrons to become odd-numbered plutonium species (e.g., Pu-240 will become Pu-241), meaning these species have a net negative reactive worth (i.e., they parasitically absorb neutrons).

However, once again - these are things which are well-understood from an engineering perspective; the amount of plutonium in the MOX rod is determined by how much "reactive worth" is necessary. One of the students who spoke (and was later quoted by the Times-Free Press) has actually studied this exact issue (differences between weapons-grade and reactor grade plutonium for reactor fuel) and found minimal differences in reactor behavior. In other words, this is most certainly not some "experimental" fuel never tried before - all of this is well-understood physics.

Everyone's a reactor engineer...


The same goes for whether reactors are "designed" for MOX fuel; reactors are designed to remove efficiently remove heat from fuel rods and contain radioactivity. Reactor cores are designed to distribute fuel assemblies such that the rate of fission (and subsequently reactor power) is as evenly distributed as possible, with minimal peaking. Thus, the argument that somehow reactors are not "designed" for MOX-loaded cores run at the licensed and designed reactor power is utter nonsense, based upon a total misunderstanding of how reactors are designed and operated.

Finally, one of the most bizarre and self-contradictory arguments was the idea that MOX fuel will uniquely lead to accelerated materials issues with reactor pressure vessels - i.e., neutron embrittlement. Again, an argument based upon a half-truth. The average number of neutrons released in fission by plutonium is again higher than uranium (a quantity known as "nu-bar"; nu-bar for Pu-239 is about 2.98, compared to 2.6 for U-235, about a 15% difference). However, the actual quantity of interest - the neutron flux (i.e., the number of neutrons actually flying around in the reactor) is directly proportional to the rate of fission - itself proportional to the reactor power. In other words, if the reactor power is held constant, all other things being equal the neutron flux will also be about the same. (There are some minor differences here, getting deeper into the technical details, but the end result is that the net difference in neutron flux basically ends up being a wash.) In other words, the argument that somehow plutonium-based fuels will somehow uniquely lead to accelerated neutron embrittlement is utterly bogus - completely notwithstanding the fact that NRC regulations require regular sampling of reactor pressure vessel materials (a "coupon" is taken from the vessel itself and tested for properties of embrittlement).

...or an economist


Not surprisingly, many armchair economists were also present among the opponents, with several pointing out the fact that the disposal of surplus plutonium in MOX fuel costs more than vitrification and disposal in a geologic repository (in this case, likely WIPP in New Mexico) in glass logs. A response to this - repeatedly brought up by myself and others present is that fissioning the plutonium is the only way it can ultimately be permanently destroyed. (This perhaps most brilliantly summarized by Dr. Howard Hall, who noted that "as a chemist, the most difficult thing for me to do is to put an atom back together after it's been fissioned.") Opponents also neglect a few key issues as well - the first and most important of which is that we have a standing agreement with Russia to destroy this plutonium in MOX fuel, namely because of Russian concerns about future retrievability in glass log form. (While the plutonium is rendered far more inaccessible in glass log form compared to its original metal pit form, it is clearly not impossible even with present technology to recover; by contrast, plutonium fissioned in MOX fuel is both destroyed, with the remaining material both contaminated with "nuisance" species like Pu-240 and Pu-242 as well as being trapped in a form which would need to be processed, while being protected by a lethal radiation field.)

Additionally neglected is the fact that the DOE has already made the decision to go the MOX route and has already invested considerable resources in making this happen, meaning any savings argument is moot; the meeting at this point involves TVA's decision to accept the MOX fuel for reactors. (Topical limitations did not stop MOX opponents from airing a laundry list of complaints against nuclear energy writ large, particularly with respect to TVA.) However, even assuming abandoning the MOX program was under consideration (neglecting technical concerns and focusing strictly upon the economic argument being presented), given the funds already committed to the MOX fabrication facility, we are well past the point where vitrification (a technically inferior solution) would even save money on the balance.

Of course, economics was not always the strong suit of opponents; a particularly amusing moment of the evening was when one opponent began his speech indicating how he hadn't paid an electric bill in over two years thanks to his home solar panels, then proceeded to preface an argument against the relative economics of MOX by saying, "As a TVA ratepayer..." It was quite clear that the meaning of "ratepayer" wasn't quite understood.

The importance of being nice

One of the most surprising things to me about the overall tone of the meeting was the general air of civility in the affair. Perhaps my expectations had been set too low on the basis of some of the zombie theatrics of Greenpeace types at prior TVA hearings (not to mention some of the horror stories Meredith Angwin has reported in connection to Vermont Yankee meetings), but overall MOX proponents and opponents alike were polite and respectful of one another. (This did not prevent the odd condescending remark from the protestors - one of the more personally enraging ones went along the lines of, "I'm glad to see all the students here tonight - but we don't need cheerleaders for MOX here, we need solutions." As if the years of hard work students put into their degree programs is irrelevant.)

One thing I stressed to students beforehand was the sage advice I took to heart from Meredith: be nice. (And if you can, bring friends.) More importantly, I tried to stress the importance of being courteous and respectful even in the face of opponents who at times took a hostile, dismissive, or even condescending tone. (At several occasions in the evening Angwin was referred to as our "patron saint" of pro-nuclear activism...) [Edit: Meredith notes that her frequent co-blogger / co-activist Howard Shaffer is even more active; I would happily amend to note the two as "co-patron saints" of nuclear activism...]

A particularly interesting facet of the meeting was in how one could readily identify MOX opponents before they even got to their arguments - solely by their tone of voice. In nearly every case, opponents would grow progressively louder as they spoke, some nearly shouting by the end (despite the presence of a microphone and room small enough that none of this was necessary).

That being said, each side respectfully allowed the other to speak - there were no disruptions or booing; generally speaking, there was even polite applause for each speaker despite whose side they represented. (An interesting finish to the story; when we wrapped up and headed out to dinner afterwards, the opponents ended up at the same restaurant, sitting at a table right next to us. While there was some mildly belligerent exchanges between one opponent and one of our students, generally speaking both sides were again polite and respectful to one another.)

Showing up matters

Lest anyone doubt the impact of knowledgable people simply showing up at meetings like this, I offer the following exercise in compare & contrast: Take a look at the coverage of the MOX hearing in Chattanooga (attended by an overwhelming number of ANS local section members from the University of Tennessee and Chattanooga State) versus the hearing on Thursday in Decatur, Alabama (near the Brown's Ferry reactor, one of the proposed TVA sites for burning MOX fuel). (For further contrast, have a look at the before and after reporting of the Chattanooga meeting as well).

The distinction in coverage when knowledgable nuclear advocates are present could not be more clear; in their absence, a small caravan of nuclear opponents traveling from meeting to meeting are allowed to speak unopposed as the singular voice of "the public." (Take a look at the articles and see if you can't spot some repeated names, for example.) There is little question in the Decatur coverage whether a contingent of the public exists who supports the program (apparently, they don't) - instead, opponents have been allowed to freely carry the day, completely unchecked.

Without trying to belabor the point too much: showing up matters. Reporters have no technical basis to evaluate the questionable claims of nuclear opponents (which really, the MOX opponents unabashedly represented); nor do reporters have any reason to seek out the existence of an opposing view when it is absent from public forums such as these. By contrast, when knowledgable individuals show up to these meetings, particularly in large numbers, their presence simply cannot be ignored - even if their numbers may be underreported. (The Chattanooga Times-Free Press reporter indicated about a dozen students were present; by my count, we had about two dozen from the University of Tennessee alone in two vans, not even counting the over two dozen from Chattanooga State.)

Final thoughts

Something to stress here in all of this - and again, something I made sure to emphasize with the students coming on their own time despite busy class schedules - is that in addition to the simple importance of speaking out at events like this (something I feel is an ethical obligation of nuclear professionals), one of the most important aspects here is to have fun. Outreach events like this can be stressful, especially with opponents ready to label students as simple shills or puppets of the "nuclear corporatocracy" to use one opponent's terms. Some of this came from having some fun with opponents' catchphrases - "Don't fall into the MOX pit!" and "Are you cheerleading or finding solutions here?" were repeated more than once in humorous fashion afterwards.

Events like this fulfill a vital part of the role of organizations like ANS to inform the public such that decisions are made on the basis of facts and not simply demagoguery, but that also doesn't mean that they can't also be a fun way for students and professionals to get together to share their passion for technology they see as vitally important for society's future.