This group brings together the best thinkers on energy and climate. Join us for smart, insightful posts and conversations about where the energy industry is and where it is going.

Post

Stop Worrying About 'Spent' Fuel Pool Fires. Zirconium Tubes Do Not Burn

The contents of this post were incorrect. I acknowledge the error and apologize.

Discussions

Glenn Carlson's picture
Glenn Carlson on Mar 22, 2011 5:19 am GMT

Mr. Adams wants to dismiss zirconium fires even though “studies performed by the Department of Energy indicate that [it] is virtually impossible to ignite zirconium tubing.” (http://resources.nei.org/documents/japan/Used_Fuel_Pools_Key_Facts.pdf)  In doing so, he doesn’t discuss the real concern raised by a fire in the spent fuel storage area of the Fukushima Daiichi plant.  A concern shared by Japanese authorities, IAEA, NEI, NRC, and JAIF, but not Mr. Adams.

A fire in the spent fuel storage area is of concern for the following reasons:

1. A fire would exacerbate the release of airborne radioactivity from the reactor building.
2. A fire could complicate regaining control of the damaged reactor by a) damaging instruments and equipment and b) preventing access to the reactor building by plant personnel.

Under conventional loss of cooling scenarios, it would take days or weeks to lose enough water to uncover the spent fuel.  But, a 9.0 earthquake, tsunami, and hydrogen explosion are not part of a conventional scenario.

The NEI recognizes that “the only way to rapidly drain down the pool is if there is structural damage to the walls or the floor.” A 9.0 earthquake might cause such structural damage, and the fuel might then be uncovered in hours or days. And, if the spent fuel is uncovered, the clad could be damaged releasing radioactivity and could oxidize generating hydrogen. A hydrogen explosion and fire could further damage the clad of the uncovered fuel. Even if the fuel remains covered, clad damage could occur if the spent fuel racks are damaged by the earthquake. As stated above, a fire would exacerbate the release of airborne radioactivity from the reactor building.

Knowledgeable authorities seem concerned about such a scenario.  JAIF reports that the water level in the spent fuel pool is “low” and “hydrogen from the pool exploded.”  The IAEA reports it “still lacks data on water levels” and “some damage to the cladding cannot be ruled out.”  IAEA also reported, “Japanese authorities also today informed the IAEA at 04:50 CET that the spent fuel storage pond at the Unit 4 reactor of the Fukushima Daiichi nuclear power plant is on fire and radioactivity is being released directly into the atmosphere.”

Excerpts and sources:

http://resources.nei.org/documents/japan/Used_Fuel_Pools_Key_Facts.pdf

The only way to rapidly drain down the pool is if there is structural damage to the walls or the floor.

If the water level decreases below the top of the fuel assembly, oxidation of the zirconium cladding could occur. This oxidation could result in some hydrogen generation. … This is extremely unlikely to occur after as little as 120 days (16 weeks) of cooling.

http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1300691852P.pdf (March 21)

Fuel integrity in the spent fuel pool [of Unit 4]

Status: Red. Water level low.  Seawater spray continue. Hydrogen from the pool exploded.

Remarks: Immediate threat is damage of the fuels in the fuel pool outside the containment vessel.

http://www.iaea.org/newscenter/news/tsunamiupdate01.html

Fukushima Nuclear Accident Update (21 March 2011, 15:30 UTC)

Water is being sprayed periodically into the spent fuel pools at Units 2, 3 and 4. The Agency still lacks data on water levels and temperatures in the spent fuel pools at Units 1, 2, 3 and 4.

It is highly unlikely that used fuel temperatures could reach the point where melting could occur, although some damage to the cladding cannot be ruled out.

David Lewis's picture
David Lewis on Mar 22, 2011 9:47 pm GMT

Telling people now there was no concern cannot convince them.

There was a concern.  Experienced level headed responsible authorities, including types like Rod, understood that the Fukushima defenses were being penetrated, level after level, to where one concrete wall of one pool fell away leaving only a presumed intact at this point stainless pool liner around what was left of the water surrounding the rods in the pool at Unit 4.  Anyone assessing the situation as it had evolved to that point must describe that to see it actually get this far was taken to be unlikely in the extreme.  

Even more unlikely events must then be looked at with fresh eyes at that point and analysed.  

Any plan that depended on water existing around the rods would have to be regarded as something that could become ineffective, and anyone responsible for the safety of the Japanese population that could be affected would have to consider what they would have to do if it became impossible to keep water around the rods.  They would have to consider what it meant in terms of warning the population that would be concerned, whatever size that might be in whatever area, if a pool full of rods went dry, say, during the next minute.  

Perhaps they would find themselves calm after they reviewed what was known.  

What Rod is saying now is fleshed out in more detail on his latest podcast.  Just after the 36th minute he goes into more detail about why he sees no credible risk even at this point. He was talking about the video he has in the above post showing a blowtorch applied to zirconium rods, when he and I believe this is Margaret Harding, a nuclear engineer he often invites on his show for panel discussion of matters nuclear, had an exchange about zirconium fires:

Margaret:  “I watched that video too.  I also watched an explosion of zirc at the facility here”

Rod:  “Ground up zirc or zircalloy tubes?”

Margaret:  “Well it was zircalloy dust.”

Rod: “Well OK.  Dust is something completely different”

Margaret:  “I understand.  But the point is it can catch fire.  What they did there is demonstrate that it is not easy.  And when you read the reports that were done a long time ago, the odds of a fire in a BWR spent fuel pool in particular are extremely low, and require a very precise organization of relatively fresh and exposed fuel to get the precise temperatures and the precise chemical conditions to cause it”.

Rod:  “Right.  And the fuel that was removed and stored in Unit 4 pool was removed from a reactor 100 days ago”

Margaret:  “Right”

Rod:  “and it is a low density storage.  Not a high density storage”

Margaret:  “Right.”

 The panel moved on at this point to other topics.  

Rod dismisses computer modelling of any vintage, what was available in 2006, or even presumably now, even though he must be aware that the US nuclear bomb inventory is certified as safe to have on US soil and effective to hold as a deterrent for US defense by computer modelling based on known properties of materials.  No atomic bomb tests have been done since 1992.  Margaret is citing “old work”, perhaps this refers to studies I’ve seen from the 1970s.  Computers were dinosaurs then.  I’m not a nuclear engineer.  I can only consult the highest level panel most recently created who stated that they reviewed all older literature and specifically addressed the situation that could result as of 2006, i.e. NRC 2006.  

Perhaps Rod is correct.  But people are going to demand verification.   

The panel from the National Academy of Sciences National Research Council, the scientists and engineers who signed their names to the 2006 report stated that computer simulations available in 2006 indicate that the scenario Rod says we should “stop worrying” about, “should not be dismissed” because at minimum, “some” of the possible release estimates which were described as indicating an event “worse than Chernobyl“, would proceed should a spent fuel pool be allowed to exist without water, or in certain circumstances, in a pool partially full.  

Rod would have us believe that the millions of people in Japan who just wanted to know what the engineers who designed the safety features of the Fukushima nuclear plant wanted to protect them from, should be told, at the point media was whipping up hysteria showing exploding reactor buildings on TV, at the height of the crisis when NRC Chairman Jaczko publicly asserted that Japanese authority was not telling their own people that the pool was empty and what was feared could be at hand, that there was nothing that serious in store even then.  

One wonders why the Japanese or the US authorities could not cite the factors Rod and Margaret now cite, then, to radiate calm. Risk has to be able to be sized up better so people can help restore calm in situations like this. One idea I had is posted here.  

Otherwise what is anyone supposed to say?  At this point, we are idiots if we don’t listen to Rod, one must presume he is saying.  Yet, the highest level most recently convened panel to study this situation says the risk at worst case was (Quotes in this paragraph are from NRC 2006)  Some fraction of the “between 10 and 100 percent of the cesium-137″ could enter the air around the plant forming a plume “that could potentially transport radioactive aerosols hundreds of miles downwind under appropriate atmospheric conditions”

A statement by the National Academy as to what it is and who its members are is here.

Don’t get me wrong here.  I like Rod.  He is a great nuclear advocate.  Anyone seeking to understand nuclear power or any issue involved with it should consult Rod’s archive of interviews and discussions he makes available at archived podcasts of his The Atomic Show  

But consider this. Rod writes, up there in this post:  “As a teacher, it was sometimes a challenge for me to help students understand that they really did need to pay attention in math, chemistry, and physics if they wanted to be submariners.

Rod seems to think he could teach, for instance, the chair of this NRC panel, something.  

I.e. Dr.Lanzerotti, who is a consultant to Bell Labs.  He worked on worked on the Voyager, Ulysses, Galileo and Cassini space missions, and is expert in geophysics and electromagnetic waves.  

Here’s another panel member Rod thinks he knows more than:  Dr. Carl Alexander, expert in the behavior of nuclear material at high temperatures and also in biological and chemical weapons. He is chief scientist and senior research leader at the Battelle Memorial Institute in Columbus, Ohio.  He helped analyze the evolution of the Three Mile Island accident and is involved in the French Phebus fission product experiments, which are to reproduce all of the phenomena involved during a nuclear power reactor core meltdown accident.  He has authored over 100 peer-reviewed articles and technical reports, many of which are classified

There were many panel members.  Their biographical data as published in the NRC report is here 

 

PS.  

Rod is also on record disputing the knowledge the highest level authorities that exist have, right up to a Nobel Committee, in a field he knows even less about than nuclear power, i.e. ozone depletion.  Rod published his views online.  He says the Nobel Committee made a mistake when they awarded Nobel Prizes to the atmospheric chemists who did the original scientific work that nailed down the cause of the ozone hole.  Rod has no theory to explain observed ozone losses other than his view that the industrial chemicals involved can’t possibly be the culprits scientific panel after scientific panel certified were in fact the cause.  Proof was found that satisfied enough countries in the world that the first and so far only treaty ever signed aimed at eliminating the production of a class of industrial chemicals was signed, i.e. the Montreal Protocol.  Here is Rod’s webpage where he will tell you more.  

 

 

Rod Adams's picture
Rod Adams on Mar 22, 2011 11:16 pm GMT

I was wrong to minimize the risk of losing water in a used fuel pool. 

David Lewis's picture
David Lewis on Mar 24, 2011 4:04 pm GMT

I tend to agree with Rod’s original thought, except I wouldn’t say the risk of fire after a loss of pool coolant wasn’t there.  I would say it may not have been there given the exact conditions prevailing in Unit #4 at Fukushima.  And so although Rod may yet be proven right in his original idea to declare the risk nonexistent, we have to see.  What I have to accept given my research so far, which is ongoing, is that the risk could have been there.  

What we need is a sober look at what the situation was at Fukushima at its worst to put this accident into perspective.  We also could take what we learn from that examination and apply lessons learned to our sites here in the US, as opposed to the knee jerk nostrums the people who want the nuclear power industry to cease to exist will suggest.  I’ve posted as a comment further down, the second one of mine below, a bit more of an examination of the NAS NRC 2006 study that has me hesitant to wholeheartedly agree with Rod’s initial minimization of the risk.  

I can’t do more research today.  

Rod is representative of the most successsful nuclear reactor program yet seen in the world, that of the US Navy.  Rickover and Rockwell ran that program when it created the world’s first commercial nuclear generating station.  Their program never had an accident.  I think they showed the world how imperfect human beings can approach nuclear power responsibly, that they proved it could be done.

Rod was hand picked by Rickover to operate one of his reactors.  He is a friend of Rockwell’s to this day.  The idea that what Rod says about how he views the risk here can just be dismissed is preposterous.  I find it very encouraging that types like Rod saw that there very likely were many factors still providing defense in depth at Fukushima at the height of the problems there.  My own experience left me shaken during the crisis and I had to accelerate my studies to get some understanding.  

We need nuclear power and we should not allow unsubstantiated fears to stop us from using it.  

David Lewis's picture
David Lewis on Mar 24, 2011 4:15 pm GMT

comment deleted to reposition it futher down…

David Lewis's picture
David Lewis on Mar 24, 2011 4:26 pm GMT

Here’s a dart I threw at a reporter, Bruce Gellerman, who works for Public Radio International on their Living On Earth radio show which I monitor via podcast.  I  have previously clashed with Gellerman, pre Fukushima, over his reporting on the risk presented by spent fuel pools at reactor sites.  Gellerman has now interviewed the author of the study, i.e. Alvarez of Alvarez et.al., which is the report that the NAS NRC examined in 2006 as a starting point in its determination of what the risk in these pools is.  Gellerman reported that the NAS NRC “agreed with” the wild assumptions of an anti nuclear guy he was featuring, I took him to task over it, and all I got back in response was “you have to extrapolate” from the NAS report, then I’d see it “agreed”.  Moving right along:

 

People should read the the report the NAS NRC published that Alvarez says “weighed in” on this issue of what happens if a pool goes dry.  Living on Earth’s Gellerman dug up a certain Gordon Thompson for his LOE’s previous report on these pools (“Waste Not Want Not”), who described US reactor pools as “radiological weapons awaiting activation by an enemy”, and Gellerman actually reported that the NAS report (I refer to it as NAS NRC 2006)  <b>”agreed”</b> with that analysis.  They didn’t.  I bring this up to caution anyone hearing this LOE report or reading this transcript that any careful observer would say LOE and Gellerman have an anti nuclear power bias this obvious.  
The NAS NRC 2006 took Alvarez et. al. scenarios and examined them.  They also noted that the NRC itself had done a study which drew “some” of the same conclusions Alvarez did, i.e. if a zirc fire broke out it “would probably” lead to a release of fission products “comparable” to what “molten fuel in a reactor core” would.  After describing that the Alvarez study had been extensively reviewed and commented upon, with people disputing Alvarez et. al. assessment of what the likelihood of a zirc fire was and how great the offsite consequences could be the NAS then wrote: “The committee provides a discussion of the Alvarez et al. (2003a) analysts in its classified report. The committee judges that some of their release estimates should not be dismissed.”
Which is a <b>very long</b> way from Gellerman’s previous report that the NAS “agreed” with Thompson’s wild statement that these pools are “radiological weapons awaiting activation by an enemy”.  
What is the actual size of this threat?  How many layers of defense were still left at Fukushima?  Given that Unit #4’s pool was packed at low density, and its exact arrangement of rods and their age, was the possibility of a fire there at all?  I.e. The NAS recommended that rods be rearranged in US pools to lower the odds of a zirc fire breaking out.  
LOE would have us believe its just let the water drain out and hell is upon us.  This is reporting?  
The NAS noted that the computer simulation results able to be examined by the NAS in 2006 had deficiencies which included “the computer models” used “had not been validated for this application”, they were described as based on “simplistic” assumptions and the NAS noted “The thermal analysis experts on the committee judge that these simplistic assumptions could produce results that are more severe (i.e., overconservative) than would be the case had more realistic assumptions been used” “
which which made it “not possible to predict the precise magnitude” of what could happen.  
Ten years of the most aggressive solar subsidy program in the world got Germany about one reactor’s worth of electricity for its grid and the cost exceeded $40 billion US.  LOE says it is an “independent environmental voice”.  I’ve been a climate activist for more than 20 years, and I remember when the NGOs didn’t make climate their main issue.  I remember when the Sierra Club advocated nuclear power.  The position the NGO environmentalist community takes on nuclear evolved before their position on climate (examine the dates on the Friends of the Earth climate and nuclear policy statements) and they have yet to reevaluate their position on nuclear by examining the facts, as opposed to assumptions created by telling each other that the facts are as LOE would have us believe.  The issue is serious and the hour is getting late.  What we need is a sober look at what happened at Fukushima and what the implications are for us in the US.  

“People should read the the report the NAS NRC published that Alvarez says “weighed in” on this issue of what happens if a pool goes dry.  Living on Earth’s (LOE’s) Gellerman dug up a certain Gordon Thompson for his LOE previous report on these pools (“Waste Not Want Not”), who described US reactor pools as “radiological weapons awaiting activation by an enemy”, and Gellerman actually reported that the NAS report (I refer to it as NAS NRC 2006) “agreed” with that analysis.  They didn’t.  I bring this up to caution anyone hearing this LOE report or reading this transcript that any careful observer would say LOE and Gellerman have an anti nuclear power bias that is this obvious.  

The NAS NRC 2006 took Alvarez et. al. scenarios and examined them.  They also noted that the US NRC (the Nuclear Regulatory Commission, as opposed to the National Research Council) itself had done a study which drew “some” of the same conclusions Alvarez did, i.e. if a zirc fire broke out it “would probably” lead to a release of fission products “comparable” to what “molten fuel in a reactor core” would.  After describing that the Alvarez study had been extensively reviewed and commented upon, with people disputing Alvarez et. al. assessment of what the likelihood of a zirc fire was and how great the offsite consequences could be the NAS then wrote: “The committee provides a discussion of the Alvarez et al. (2003a) analysts in its classified report. The committee judges that some of their release estimates should not be dismissed.”

Which is a very long way from Gellerman’s previous report that the NAS “agreed” with Thompson’s wild statement that these pools are “radiological weapons awaiting activation by an enemy”.  

What is the actual size of this threat?  How many layers of defense were still left at Fukushima?  Given that Unit #4’s pool was packed at low density, and its exact arrangement of rods and their age, was the possibility of a fire there at all?  I.e. The NAS NRC 2006 recommended that rods be rearranged in US pools to lower the odds of a zirc fire breaking out.  

LOE would have us believe its just let the water drain out and hell is upon us.  This is reporting?  

The NAS NRC 2006 noted that the computer simulation results able to be examined by them in 2006 had deficiencies which included “the computer models” used “had not been validated for this application”, they were described as based on “simplistic” assumptions and the NAS NRC 2006 noted “The thermal analysis experts on the committee judge that these simplistic assumptions could produce results that are more severe (i.e., overconservative) than would be the case had more realistic assumptions been used” which which made it “not possible to predict the precise magnitude” of what could happen.  

Ten years of the most aggressive solar subsidy program in the world got Germany about one reactor’s worth of electricity for its grid and the cost exceeded $40 billion US.  LOE says it is an “independent environmental voice”.  I’ve been a climate activist for more than 20 years, and I remember when the NGOs didn’t make climate their main issue.  I remember when the Sierra Club advocated nuclear power.  The position the NGO environmentalist community takes on nuclear evolved before their position on climate (examine the dates on the Friends of the Earth climate and nuclear policy statements) and they have yet to reevaluate their position on nuclear by examining the facts, as opposed to assumptions created by telling each other that the facts are as LOE would have us believe.  

The issue is serious and the hour is getting late.  What we need is a sober look at what happened at Fukushima and what the implications are for us in the US.  

 

Get Published - Build a Following

The Energy Central Power Industry Network is based on one core idea - power industry professionals helping each other and advancing the industry by sharing and learning from each other.

If you have an experience or insight to share or have learned something from a conference or seminar, your peers and colleagues on Energy Central want to hear about it. It's also easy to share a link to an article you've liked or an industry resource that you think would be helpful.

                 Learn more about posting on Energy Central »