Tuesday, December 6, 2011

Post # 58: New Planets, Water, Fracking, and Energy

Water is the substance of life.  You and I are mostly water.  Life, as we know it, isn't possible without water.  Just yesterday NASA announced the discover of a new "earth-like" planet – Kepler-22b.  This planet joins a list of over 500 other recently-discovered planets that potentially have the right temperatures, atmospheres, and surface conditions to support life as we know it.  The presence of liquid water is a key metric of the "friendly-to-life" assessment.

As a young boy I occasionally accompanied my father and grandfather, who were involved in the operation of a rural east Tennessee water utility district, on visits to the large springs that were the utility's water source.  I was then and am still fascinated and amazed when I see enormous volumes of cool, clean water erupting from the ground.  There's something magical about a spring.

Some of you know I'm a supporter of the Nature Conservancy, and a long-time member of Trout Unlimited - a cold water fishery conservation organization.   As I sit here this morning typing these words, it's raining in East Tennessee.  It rains a lot in East Tennessee.  We are blessed with a abundant surface water - springs, ponds, streams, rivers, and man-made lakes.  Or at least we have been blessed in the past.  Surface water is a precious commodity.  In recent years Tennessee, like many of our sister states in the southeast, has experienced some unusual extremes in weather, and repeated periods of drought.   (Just last week, we experienced a period of heavy rain and flooding.)

I think a lot about water and energy-water nexus issues.  This is one of the reasons I'm so interested in the increasing using of fracking in the natural gas and oil production industry.  I'm not the only one watching this issue closely.  Witness the Wall Street Journal's article in this morning's edition.  Fracking, or hydraulic fracturing, is a technique in which water (normally surface water), sand, and chemicals is injected into deep natural gas and oil wells as a means to extract more "dino-fuel" from the surrounding geological deposits.

A typical oil or natural gas well drilling project in the eastern U.S. shale deposits might use ~ 65,000 to perhaps 600,000 gallons of water during the drilling process, and another 5,000,000 gallons during the natural gas extraction process.  So, let's say ~ 6,000,000 gallons or so.  Sources I've consulted indicate this about the amount of water used by New York City in ten minutes, by a 1 GWe coal-fired power plant in less than a day, a typical golf course in about a month, or perhaps 10 acres of corn in a season.  But of course, the ultimate destiny (location, content, temperature, etc) of the water used in these differing applications is very different.

At this juncture, I'm not opposed to fracking.  But I am increasingly concerned.  Fracking is currently banned in France, and in portions of Australia, South Africa, and Canada.  The natural gas industry is working hard to keep fracking safe, and is adamant that the probability of a major leak into a near-surface aquifer is extremely low.  However, as I've mentioned before, the potential for a "Black Swan" event in which a fracking operation pollutes a major ground water aquifer is never far from my thinking.  Such an event could radically change the outlook for fracking in the U.S. and elsewhere – along with the rosy predictions for abundant natural gas supplies in the coming decades.

Just like nuclear power, one of the "costs" of fracking will be eternal vigilance on the safety and environmental protection fronts.  I'm not a geologist, but one has to wonder about the long-term disposition of these wells and whether there are "failure modes" that could provide pathways for ground water contamination over decades as the subterranean well structures age.

Access to clean air, clean water, and abundant energy are the most important enablers of a life on this planet relatively free from hunger, ignorance, and suffering.  So these issues are inextricably intertwined from cradle to grave on both the production and utilization sides of the equation.  We all have a stake in the continued safety of fracking - a process that seems destined to expand greatly as we seek to extract more oil and gas for an energy-hungry world.


Monday, November 21, 2011

Post # 57: Energy Technology: The Innovation Challenge

I've been doing a lot of thinking during the past several months about innovation (or the lack thereof) in the energy sector.  By innovation, I mean the entire process from basic discovery though technology implementation and impact.  (I'm all about impact these days...)

This seems to be a timely topic.  Time Magazine's current issue carries the title, "The Invention Issue."  Of course, invention is but one step in the chain between discovery and impact.  I thought I might offer some snippets from my current stream of consciousness about innovation in the energy sector.  We'll focus on patents as one indicator of innovation.  (Again, patents are only one indicator reflective of one milepost in the road between discover and impact.)

Why all the focus on innovation?  Michael Mandel, the Chief Economic Strategist at the Progressive Policy Institute, recently posted on the Atlantic website a pointed article about the importance of innovation to our economy.  The article, entitle "There Are Only Two Ways to Save the Economy:  Innovation or Inflation" is good reading.  His core message is that if our economy is to recover, we must either grow (through technical innovation that leads to job growth and overall economic growth), or we must purposefully inflate our way out of the mess we're in.  He states, "...we have to shift from a consumer economy to a production economy. This is partly about a change in spending patterns, but also about a change in attitude. For example, we need to boost R&D and other investment in knowledge capital, but we also need federal regulatory agencies to encourage rather than discourage innovation. We need more infrastructure spending and other investment in physical capital, but it should be directed towards supporting exports and production in the U.S., rather than clearing up bottlenecks of imported consumer goods. This profound shift in policy and behavior is essential over the long run, but it won't be easy or quick."

I'm obviously sympathetic to Michael's argument.  I recently had an extended discussion with Charles Barton of The Nuclear Green Revolution blog.  Innovation was one of the many subjects we discussed.  (Charles has posted most of the content of our discussion on his blog.)    My comment to Charles was,

"The environment in today’s nuclear energy enterprise is hostile to innovation.  Not by intent, but in reality nevertheless.  The industry is highly regulated.  It is very costly to do research, development, and demonstration.   It’s a very capital-intensive business.  The barriers to entry are incredibly high.  The down-side risks of innovation are more easily rendered in practical terms than the upside gains.  Often it seems everyone in the enterprise (federal and private sectors) are so risk-averse that innovation is the last thing on anyone’s mind.  In this environment, “good-enough” is the enemy of “better”.  Humans learn by failing.  It’s the way we learn to walk, talk, and ride a bicycle.  Our environment today has little tolerance for failures at any level.  There’s no room for Thomas Edison’s approach to innovation in today’s world.  On top of all of this, or perhaps because of it, the nuclear industry invests less on R&D, as a percentage of gross revenues, than practically every other major industry you might name."

So this got me to wondering about innovation in other energy sectors.  One of the sources of information I turned to was the World Intellectual Property Organization (WIPO).  WIPO's document, Patent-based Technology Analysis Report – Alternative Energy  summarizes almost 78,000 recent alternative energy patent applications from the U.S., Europe, Japan, Korea, the People's Republic of China, and WIPO's patent office.  The data roughly covered the period between 1976 and 2008.  (In case you're wondering, only 15,326 of those patent applications came from the U.S. Patent Office.  An amazing 42,842 of them came from the Japanese Patent Office.  That's more than everyone else combined!) The analysis focuses on solar energy, wind energy, bio energy, hydro energy, geothermal energy, wave/tidal power, hydrogen, fuel cells, carbon capture and storage, and waste-to-energy (using stuff otherwise destined for landfills for direct burning or liquid fuels production).  There are several interesting analyses in the report.  One insight (their Figure 2) is that the global rate of patent filings peaked around 2003 and has since decreased (caveat:  no data for 2009 and later years).

Total alternative energy patent applications and application growth rates (Ref: Figure 2 from "Patent-based Technology Analysis Report – Alternative Energy," WIPO.

A second insight is that the rate of alternative energy patent applications in the U.S. peaked in 2002 at just a bit more than 1500, dropped by 20% to around 1300 in 2004, and was headed downward at a pretty fast clip at that time.

One of the most interesting observations is WIPO's analysis of the global pattern of patent activity.  I quote from their report,

"A general model for patterns in patenting activity can be established to understand the stages of development of a particular technology. On the introduction of a new technology, only a small number of applicants are involved in patenting in the field and only few applications are filed. Following this growth period, the technology enters a development period, during which the technology develops rapidly as a result of active competition between numerous applicants, who together file many applications. As research and development continues, the growth in the number of applications stagnates or declines as does the number of applicants. This period can be termed a “maturity period”. As new technologies or even entirely new technology paradigms emerge, a period of decline begins for the original technology, at which point the number of applications and applicants in that field declines strongly. It is possible for a revival of interest to occur in the original technology, if a new application can be found for it, leading to resurgence in the number of applications and applicants (KIPI 2005)."

Figure 4 from their report is a graphic depiction of this pattern (I apologize for the poor quality of the clip):

A general model for patent filing activity (Ref: Figure 4 from "Patent-based Technology Analysis Report – Alternative Energy," WIPO.

One has to wonder how the superposition of the nuclear energy innovation challenges I mentioned above impacts this model.  I believe most of these challenges lead to "technology lock-in" and "loitering" in Stage III of the process.

A number of other organizations, including the International Energy Agency (IEA) 2009 are engaged in the business of spurring and coordinating energy R&D.  See, for instance, IEA's reports on global energy R&D portfolios.

Margolis and Kammen argued in the 30 July 1999 issue of Science (Vol 285 no. 5428 pp. 690-692) that R&D intensity in the U.S energy sector was extremely low and was reducing the capability of the sector to innovate.  Looks like little has changed...

So, I will continue to bombard the energy technology innovation issue with simple questions. "What is the innovation process, and how does the process work (or alternatively, why doesn't it work?" "Who's doing the innovating?"  "Where is innovation happening?"  "How can the innovative cycle be accelerated?" These are not simply intellectual sandbox exercises.  The quality of life of billions of our fellow human beings around the world depend on the answers...  Here's to success!

Just thinking...


Wednesday, November 9, 2011

Post # 56: Sobering News From International Energy Agency

The International Energy Agency (IEA) released its World Energy Outlook 2011 today.

I'm still absorbing the analysis, but the best way to describe the message of the report is "sobering".

According to IEA analysis, unless the world takes "bold" action (their term) to change our energy policies, we will be locked into an "insecure, inefficient and high-carbon" energy system.  They go on to say, "Governments need to introduce stronger measures to drive investment in efficient and low-carbon technologies.  The Fukushima nuclear accident, the turmoil in parts of the Middle East and North Africa and a sharp rebound in energy demand in 2010 which pushed CO2 emissions to a record high, highlight the urgency and the sale of the challenge."

The IEA typically explores futures by scenario analysis.  The "New Policies Scenario" is, given our current direction, probably the best that can be hoped for.  In this scenario, recent government commitments are implemented in a "cautious" manner.  Under this assumption, and given current population and economic mega-trends, the year 2035 looks like this:

  • Total global primary energy demand has increased by 1/3 relative to 2010 levels.  Ninety percent of this demand growth is in non-OECD countries.  China is consuming 70% more energy than the U.S., with per-capita demand still less than half that of the average American.
  • The percentage of energy supplied by fossil fuels drops from today's 81% to 75%.  Renewables share of energy production rises from 13% to 19%, based on subsidies that rise from $65B in 2910 to $250B in 2035.  (Want to take odds on all those subsidies coming through?)  It is worth noting, though that the IEA calculates that global fossil subsidies in 2010 amounted to $409B.
  • Oil demand rises from 87 million barrels/day in 2010 to just 99 million barrels/day in 2035.  Virtually all of this is driven by growth in the transportation sectors of emerging economies. (Everyone wants a personal automobile.)
  • The 2035 price of oil is assumed to reach just $120/barrel in 2010 dollars.  (I think this is a low-ball assumption).
  • The use of coal RISES 65% by 2035.
  • Nuclear power output rises by only 70% by 2035.
  • Natural gas's share of energy production rises dramatically, almost equaling that of coal.
  • Carbon dioxide emissions between 2010 and 2035 amount to 3/4 of the total emitted during the past 110 years.
  • Approximately $38 Trillion in investments is required by 2035 – about $1.5 Trillion per year – to achieve this scenario.  The investment breakdown is: $16.9 trillion in the Power sector, $10.0 trillion in the Oil sector, $9.5 trillion in the Gas sector, and $1.2 trillion in the Coal sector.
  • The global average temperature rise is 3.5 ºC.

The IEA also looked at a "450 Scenario", which lays out a pathway to to achieving a 2ºC global average temperature rise.  There's some really sobering news here. According to EIA's analysis, given the existing energy infrastructure in place, all of the emissions allowed through 2035 will be emitted by 2017.  We are "locked-in".   A major redirection of global policies would be required to address this problem.  According to the EIA, "Delaying action is a false economy: for every $1 of investment in cleaner technology that is avoided in the power sector before 2020, an additional $4.30 would need to be spent after 2020 to compensate for the increased emissions."  As they say, "the door to 2ºC is closing...

The IEA also conducted some interesting parametric analyses which they've not yet posted.  They have a "low nuclear" variant in which nuclear energy drops by 15% by 2035.  They also focus quite a bit of attention on China's per-capital energy demand growth...  Most of the variants appear to make matters worse.

Given all of this news, and an attention deficit world awash in all sorts of distractions, it's not unreasonable to consider scenarios in which efforts to reduce carbon emissions are not successful.  In that event, we can (a) hope the climate modelers are wrong, (b) pursue terra-forming to alter the atmospheric dynamics, or (c) prepare to deal with all of the ramifications of a warmer climate.

Quite a Gedanken Experiment!


Monday, November 7, 2011

Post # 55: Nuclear Energy - Fallen and Can't Get Up ?

Last week I attended the winter meeting of the American Nuclear Society (ANS) in Washington, D.C.  It was a time to catch-up with friends and colleagues; let folks know that though I've "retired" from ORNL, I have not retired; and hear the latest technical and business updates from the nuclear energy community.

I must admit I left the meeting with a touch of the "blahs".  The tone of the meeting, from beginning to the end, was "haunted"  (Halloween occurred during the meeting) by three underlying thoughts: (1) the overall US and global economic malaise, (2) real and potential repercussions from the Fukushima Dai-ichi incident, and (3) the blessing/curse of cheap natural gas.  These realities directly and indirectly resurfaced multiple times while I was there.

I'm reminded of the famous TV commercial from several years ago involving an elderly lady who's laying in her kitchen floor calling out, "Help!  I've fallen and I can't get up!".   I couldn't help but wonder, "Is this dear lady's exclamation a metaphor for nuclear energy?"

It seems every time during the past 25 years we were on the verge of a "nuclear renaissance", a major setback occurred... Is this "deja vu all over again" as Yogi Berra famously quipped?  Sure looks like it - in the U.S. and Europe at any rate...

The continuing domestic and global economic malaise has two major short-term impacts on nuclear power:  (1) it decreases electric load growth rates, and (2) it creates a risk aversion paranoia in the financial sector.  The first factor enables utility planners to delay capacity additions needed to meet load growth.  The second factor makes it more difficult for companies to proceed with capital-intensive endeavors.  Small Modular Reactors (SMRs) have the potential to help in the second case, by reducing both the lump sums of capital to be borrowed, and providing earlier revenue generation from the capital that is borrowed. (More about SMRs later...)

I'm happy that natural gas prices are as low as they are.  I cook with natural gas, dry my cloths with it, and heat my house with it.  But I wonder... what if fracking turns out NOT to be the panacea it is currently believed to be by many in the gas industry?  The future for domestic gas production would be severely impacted if fracking were to become an unacceptable practice.  What might lead to this outcome?  An "accident" in which a major aquifer becomes contaminated and unusable for human consumption.  That could be a Black Swan for fracking.  I hope it never occurs, but I shared here before my concern about the potential environment impacts of widespread fracking.

The echos of the Fukushima accident still ring loudly in the nuclear industry and will continue to do so for years to come.  One of the immediate impacts of the Fukushima accident was a major scaling-back of business expansion and staffing plans by major nuclear vendors and suppliers.... a "hunkering-down" so to speak - in anticipation of a major knee-jerk response from governments and customers around the world who had new nuclear power construction plans on the table.  And we have seen quite a bit of this response in Europe to be sure.

As I write this, futures prices for natural gas are sitting around $4 per million BTU.  That's certainly not "too cheap to meter", but it's cheap.  This reality is dominating the near-term behavior of energy suppliers in our country (and in many - but not all - other countries).  One of the presentations I saw at the embedded ANS 2011 SMR Conference concluded that at natural gas prices of $6 per million BTU, virtually no other electrical generating technology (coal,  SMRs, etc) will be competitive – unless carbon emissions are penalized.  That means free market forces are unlikely to result in much new generating capacity other than gas-fired units for the foreseeable future.

So, am I bullish on nuclear energy?  YES - in the mid-to-longterm!  Friedman has said the world is "Flat, Hot, and Crowded".  In my view, all three factors create a demand for safe, affordable, sustainable nuclear energy.  Flat: the nuclear industry is global.  Hot: Nuclear is among the lowest carbon emitting energy technologies on the planet.  Crowded:  Four billion people need energy – now.  Nuclear energy is the only technology within our reach that can address a major portion of this need.

The middle-east appears poised to move ahead with nuclear energy.  China and other parts of the Pacific Rim outside of Japan are moving.  There are serious rumblings on the African and South American continents.

Where's the U.S. leadership?

Wednesday, October 26, 2011

Post # 54: Faith and Nuclear Technology – The UT Baker Center Panel

It's been almost a month since I departed from ORNL.  Doesn't seem possible.  I believe I've been busier during the past four weeks than at any time in the past year!  You may have guessed this from my absence here....  In any even, "I'm back ..."  The length of this post will probably make up for my long absence (smile)...

Monday evening of this week I had the pleasure of participating in a public panel discussion hosted by the University of Tennessee's Howard H. Baker Jr. Center For Public Policy.  The forum, entitled, "Nukes & Faith - Discussing Religion's Role in Nuclear Society and Energy".  The forum was sponsored by the Tyson House Episcopal & Lutheran Campus Ministry, The Institute of Nuclear Materials Management, the UT Religious Studies Association, and the Baker Center.  Mark Walker and David Burman, UT graduate students in nuclear engineering and religious studies, respectively, were the able organizers and moderators of the panel.  My fellow panelists were Howard Hall (Governor's Chair Professor of Nuclear Engineering), Brandon Prins (Associate Professor of Political Science), and Jeffrey Kovac (Professor of Chemistry).

The UT Beacon ran an article today summarizing the  lively and sometimes provocative discussions.  Dr. Hall summarized the global status quo with regard to nuclear proliferation and some practical challenges associated with nuclear disarmament.  Dr. Prins summarized extant research on the role of religion in major conflicts, and Dr. Kovac presented a nice synthesis of the various factors that combine to influence one's world view.  Dr. Kovac and I were the two panel members who were explicitly asked by the organizers to discuss the role our faiths play in our approach to the challenges and opportunities posed by nuclear technologies. (Dr. Kovac is a Unitarian Universalist and I am an Evangelical Christian.)

The majority of the discussion dealt with nuclear weapons, nuclear proliferation, and nuclear disarmament.  Nuclear energy was discussed to a somewhat lesser extent, though I focused much of my personal attention on nuclear energy.

So here is a condensed version of my comments on the major areas I was asked to address in the panel discussion:

1.  What is the Evangelical Christian framework for consideration of matters such as nuclear proliferation and nuclear energy?

A Faith or a Belief System that does not equip and enlighten one to address the most profound matters of life is not really a "Faith".  It's only a hobby.  An Evangelical Christian will approach the topic of nuclear weapons and nuclear energy (or any major issue for that matter) by first synthesizing the relevant Biblical context.  The Biblical context is then combined with temporal facts relevant to the topic.  So, what are the relevant Biblical principles?  Here's my personal list:
  • All humans are created in God's image, are precious to him, and have intrinsic dignity and worth based on this fact.
  • We are called to be good stewards of God's creation - including of course, this planet we all inhabit.
  • We live in a very imperfect world.  Humankind and all creation is fallen - corrupted by sin.  We have a "sinful nature" that places us in constant rebellion against God and our fellow man.  This corruption distorts our reasoning, motivations, judgment, and actions toward God and our fellow man.  Evil is real and exists in the hearts of men and women.
  • Left to our own devices, we are helpless to restore our right standing with God and our fellow men.  It is for this reason that Jesus Christ came into this world, born of a virgin, lived a perfect life, suffered and died on the Cross, and rose form the dead three days later – to pay the price for our rebellion and restore our relationship with a Holy God.  
  • It is by embracing the person of Jesus Christ and his finished work on the Cross that we are restored to a right relationship with God.  Evangelical's speak of this as the "Gospel" or "Good News".  We are called to share it with everyone.  Note I said "share with".  Not "force our views on" everyone.
  • Evangelical Christians are called to live in obedience to Jesus's teachings and Biblical doctrine regarding accountability to God and to our fellow man. We are to share the Good News, resist evil, promote peace, and minister to our fellow man.
2.  Can technology be intrinsically good or evil?

This is a really complicated question.  The technologies being discussed by the Baker Center panel were nuclear weapons and nuclear power.  One must begin by defining, precisely, the "technology" under consideration.  A nuclear weapon is a particular embodiment of a suite of technologies and knowledge bases.  Ditto a biological weapon – an integrated package.   If one takes the view a biological weapon is intrinsically evil because it is intended for one purpose - the taking of human life - one then has to question the study of microbiology, microbe engineering, etc. – because they are some of the essential enablers of a biological weapon.  In the case of nuclear weapons, it's the fission and fusion knowledge bases that are enabling.  These weapons could not exist without these knowledge bases.  However, the same knowledge base can be employed to end human life or save it.  At what point along the pursuit of knowledge and integration of technologies does something become evil?  Or is it simply the motives of the integrator or creator of a device?  Or is it like the statement often made about pornography - you know it when you see it?

The history and (arguably) the success of the doctrine of Mutually Assured Destruction (MAD) is also a relevant anecdote.  MAD is a cold war doctrine practice by the US and USSR.  MAD basically stated that so long as each side could completely destroy each other, neither would launch an attack or provide an escalation of conventional conflict to the level that would trigger the use of nuclear weapons.    I am one of many who believe the enormous stockpiles of nuclear weapons on the US and USSR sides during the cold war probably prevented a number of conventional wars that would have resulted in massive loss of life.  IF this is indeed true, it challenges one's thinking about the evil of nuclear weapons.  Is a nuclear weapon "evil" while it is sitting on a shelf, preventing the loss of life simply by its existence?

However, today's global situation is, in many ways, much more complex that the cold war situation.  More dangers and threats from more directions than was the case in 1960.  The US and Russia have made significant progress in reducing the number of warheads in our arsenals, while several other nations have joined the nuclear arms club.  And then, of course, there are the "sub-national" and terrorist groups...

3.  What is the Evangelical Christian view of nuclear weapons and nuclear proliferation?

Two of Christ's most relevant teachings are: (a) Luke 6:27 "But I say to you who hear, Love your enemies, do good to those who hate you..." (ESV); and (b) Luke 10:27 "You shall love the Lord your God with all your heart and with all your soul and with all your strength and with all your mind, and your neighbor as yourself." (ESV)  Another relevant teaching is James 4:17 "So whoever knows the right thing to do and fails to do it, for him it is sin." (ESV)  I also believe Paul's teaching in Romans Chapter 13:1-5 regarding the ordained role of governments to "bear the sword" and be an agent for good is relevant.

So, what am I to do when my "enemy" (whom I am to "love, do good to") and my "neighbor" (whom I am to "love as myself") are harming or killing each other?  What am I to do when two neighbors (whom I am to love) are killing each other?  What about when an "enemy" or a "neighbor" threatens to kill, inflict suffering on, or otherwise oppress the citizens of an entire country?

Love does not mean allowing someone to do whatever they wish - to themselves or to others.  Love  means acting in the best interests of others.  If I have it within my power to prevent or stop killings, oppression, or suffering, when does Biblical doctrine require me to act?  Christian theologians have wrestled with this issue for two thousand years.  St. Augustine and Thomas Aquinas both offered considered views on the matter.  Today, the "Just War Doctrine" traces it's origin in part to their thinking.  Though too complex to discuss here, I believe, the Just War doctrine encompasses a Biblically-consistent decision framework for the use of force against our fellow man.  However, it is far from perfect.  I believe it is rare for a war to meet the "Just War" conditions.  It is even more rare for a conflict that began as a "Just War" to continue to meet the conditions of a "Just War" as it progresses.  Again, we live in an imperfect world.  Sometime there are no good options.

Turning from the Biblical perspective to the more "mundane" global perspective, my view on nuclear weapons and nuclear proliferation is similar to my view about carbon in the atmosphere - more is not better.  Though the "knowledge genie" is out of the bottle, it is right to work to limit the spread of weapons of mass destruction and to reduce the numbers of warheads as global conditions provide opportunities to do so.

4.  What is the Evangelical Christian view of nuclear energy?

This is the easiest question of the four.  As I type these words, we are days away from the birth of the 7 billionth person on this earth.  One of the clear realities of our time is that the quality of life of an individual or a society is dominated by it's access to affordable and reliable energy - electricity in particular.  Electricity is the key enabler of access to clean water, sanitation, conditioned living space, and food production.  Currently, 25% of the human population of our planet has NO access to electricity.  Another 35% or so have severely limited access.  That's roughly 4 billion people whose quality of life and life expectancy is prisoner to the lack of electricity.

So how much electricity would be needed?  I've run the numbers.  Based on current per capita electricity consumption data, roughly 2 TW of new electrical generating capacity would be needed to raise the standard of living of those 4 billion people to that current enjoyed in the nation of South Africa (per capita electricity consumption ~ 5500 Kwh annually or an average of 630 watts continuously).  Two-three times this much would be required to raise the standard of living of these 4 billion people to that enjoyed in the U.S and western Europe (~ 12,750 kwh annually or an average of 1455 watts continuously).  The total global electrical generation capacity today is ~ 4.5 TW (4500 GW).  This means we need to increase the net global electrical generating capacity by almost 50% in order to provide the South African standard of living to these 4 billion people, and we would have to more than double the total global generating capacity to raise their standard of living to that we enjoy in the U.S.  This is a staggering challenge.

As a Christian, I feel we have a moral imperative to help our fellow man climb out of this energy supply "black hole".   Beyond that, I feel strongly that the imbalance in quality of life and standard of living between those who have ready access to energy and those who do not will become one of the most disruptive global forces at play through the balance of this century.  As a energy technologist, I'm convinced nuclear power is the only practical hope we have to address this enormous energy supply problem.

So there you have it... I've not related all the details of our Baker Center panel discussion, but enough to give you an idea of where I stand on these issues and why.



Monday, September 5, 2011

Post # 53: Farewell To ORNL

Some of you may know I announced my retirement last week from ORNL, effective September 29, 2011.

I joined ORNL in December 1978 – just three months before the accident at Three Mile Island.  It has been a wonderful 33 years.  I've had the privilege of working with and learning from some of ORNL's pioneers of nuclear energy science and technology – folks like Walt Jordan, Don Trauger, Irv Spiewak, Truman Anderson, Tom Cole, Paul Kasten, Howard Bowers, Dave Eissenberg, Tom Kress and George Parker - just to name a few.  I even had the privilege a few years ago of spending one bright Spring afternoon alone with Alvin Weinberg in his study.  We discussed his extraordinary career and his vision for a world powered by nuclear energy.  I've worked along side many extraordinary engineers, scientists, and leaders from across the national laboratory complex, DOE, NRC, NASA, and the nuclear industry.  What a blessing!

ORNL has been a wonderful environment for learning and personal growth – a nurturing and empowering environment for one who considers himself an "R&D entrepreneur" and problem solver.  It has been a place where one is limited only by one's vision – and one's ability to "infect" others with that vision.  Working at ORNL has been a gift – actually a "dream-come-true" for a boy from rural east Tennessee whose family had never educated anyone beyond high school.  I grew up hearing about that magical place in Oak Ridge where they were changing the world, and I wanted to be part of it. And so I have been.

Most of my career at ORNL has been involved in the pursuit of what I call "probletunities" (opportunities masquerading as problems), and building teams of talented people to pursue them.  It is the successful solution of a problem that captures the headlines.  It's the bonds one forms with one's colleagues that captures the heart. 

So where to from here? 

Though I am retiring from ORNL, I am NOT retiring from my career.  I just feel the timing is right for a change, and I'm excited about moving to the next phase of my career.  But, I do not know where the Lord will lead me next.  Our nation and our planet are faced with a number of grand probletunities.  I do not intend to sit on the sidelines with so much to be done.  At this point in my career, I'm all about impact.

My knowledge of the DOE, NRC, NASA and NNSA corporate cultures affords opportunities to continue to have impact at the national level.  From the technical perspective, my career has been centered in nuclear energy.  During my years at ORNL, I've delved deeply into BWR severe accident analysis and reactor safety, advanced reactor concept development, reactor-based weapons plutonium disposition, space power (fission and radioisotope), reactor and power plant siting, and a host of other research areas. 

My interests have broadened in the past several years to include strategic energy issues, energy policy and R&D strategy, sustainable energy, Design Thinking, and the application of evolutionary computational techniques to the solution of "wicked problems".  

I believe high temperature fluoride salt cooled reactors could be a key element of a transformational national energy infrastructure.   As some of you know, I've devoted quite a bit of effort during the past couple of years to the development of a practical concept for a small modular fluoride salt-cooled high temperature reactor – the SmATHR concept.  I've had the pleasure of leading a highly talented group of engineers at ORNL in the development of a pre-conceptual SmATHR design.  I hope to continue to evolve the SmATHR reactor system and energy storage concept after my departure from ORNL. 

During all these years, I've taken pleasure in teething the opportunity out of the probletunity; birthing, executing, and completing R&D projects and programs; and adding value everywhere possible. Most of all, I've enjoyed solving problems through the enlightened application of science and technology, innovative thinking, and empowering my teammates.  After all, a successful R&D project is not one that simply grows and continues.  The measure of a successful R&D project is completion and delivery of the solution – whether it be an idea, and analysis, a technology, or a system.

So as you might guess, I'm not quite sure what I want to be when I grow up!

I'll continue to share my thoughts here and hope you will "stay tuned" to my stream of consciousness on sustainable energy.  Please contribute to the dialog.  Your comments are always welcome! 

And please checkout my new website @  www.sherrellgreene.com  


Friday, August 19, 2011

Post # 52: Moving toward practical electric cars

Just the other day I had a brief, but interesting conversation with a colleague of mine at ORNL who recently purchased a Nissan Leaf all-electric automobile.  I've looked at them myself and they are well engineered.  Anyway, I asked my friend how he likes his new Leaf.  His answer was interesting...

"It's a great third automobile," he said.  "Third?" I asked.  Yes, "Third" he retorted. "It seems about once a week or so, both my wife and I have 100+ mile days.  The Leaf doesn't have the range to handle this demand.  So it has to be our third vehicle."  He went on to say that he drives the Leaf to work most days every week, and really enjoys the drive.  The vehicle is solid, extremely quiet ("habit forming" he said), and because the batteries are under the seats, it has an extremely low center of gravity.

I can certainly vouch for the speed of the car.  He has passed me on the local interstate highway several times when I was driving the speed limit (65-70 mph) (smile).

Nissan and my friend are pioneers - path finders - for all of us.

Now if we can just get that mileage up to 200 miles per charge.  Then (at least here in rural east Tennessee) the Leaf could graduate to "second car" status.  I hope that day is not far away.

Just thinking...


Sunday, August 14, 2011

Post # 51: My NHK Interview on BWR Severe Accidents

Several weeks ago, Japan's NHK network sent a crew over to interview me about Boiling Water Reactor (BWR) severe accidents and BWR reactor safety in the wake of the March 11 earthquake / tsunami in Japan and the resulting accident at Fukushima Dai-ichi.  I understand the interview is to air around mid August.  This posting is the text of my notes from the interview...

QUESTION 1.     What was analyzed in "SBO at Browns Ferry Unit One-Accident Sequence Analysis"?

A “Long-Term Station Blackout” sequence was analyzed in the 1981 study.  The Browns Ferry Unit 1 plant (A BWR-4/Mk-I) was assumed to be operating at 100% power when an unspecified event was assumed to occur which eliminated all off-site power and disabled the on-site backup emergency diesel generators.  Otherwise, the plant was assumed to be undamaged and fully functional.

Using the best available computer models at the time, the ORNL team analyzed the sequence of events following accident initiation, assuming a 4-hour station battery lifetime.  A few different variations of the accident were studied, but the basic sequence assumed the then-existing operational procedures and accident mitigation system actuation procedures were followed.  The study identified the major accident sequence events, event timing, and characterized the overall accident sequence progression from the initiating event up until primary containment failure

As expected, the simulations indicated that up until the time the station batteries were exhausted at 4 hrs, the plant incurred no damage and could recover normally during that period if diesel generators or off-site power were recovered.

4 hr – loss of reactor vessel injection as batteries are exhausted
5 hr – top of core is uncovered
7 hr – the lower head of the reactor vessel fails
8.5 hr – primary containment drywell EPAs fail

In later studies with a 6-hr battery life, and assuming the reactor is depressurized, reactor vessel failure is delayed until ~ 10.5 hrs, and reactor vessel failure is delayed until ~ 15.5 hrs.

QUESTION 2.     Numbers of accident sequence analysis have done on other reactors. Compare to other types, what were the distinctive feature of Browns Ferry Unit One or Mark 1?

With regard to the reactor, Browns Ferry Unit-1 was originally a 3440 MWt / 1152 MWe BWR-4, with an operating pressure of ~ 1020 psig / 7 MPa an operating temperature of 530 F / 275 ºC.   While BWR power levels vary, the operating pressure and temperatures of BFNP-1 were characteristics of most BWRs.  PWRs operate at about twice the pressure of BWRs.

With regard to the containment, BFNP-1 is a Mark-I containment similar to Fukushima Dai-Ichi.  The primary containment consists of a compact “drywell” which encloses the reactor vessel.  The drywell is connected to a large torodial “wetwell”, which contains a ~ 1 million gallon “pressure suppression pool”.  All BWR’s employ suppression pools.  PWRs do not employ pressure suppression pools.  Primarily as a result of this fact, and the much higher operating pressure of PWRs, PWRs generally have larger primary containments around the reactor vessel to accommodate the blowdown of steam and water from the reactor vessel in the event of a loss of coolant accident.

A “reactor building” secondary containment surrounds the primary containment, housing most of the critical operating system components, as well as providing space for the refueling pool and other plant processes.  This secondary containment concept is common to all BWRs, but is not employed in the same manner in PWRs.

QUESTION 3.     Did you identify vulnerabilities of the design? e.g. shorter meltdown time, size of containment, problems of ECCS, probable hydrogen explosion and etc.

ANSWER: As a newbie at the time in 1981, I was surprised that the estimated station battery lifetime was just 4-6 hours.  But this was the norm in nuclear power plants at that time.  Other than observing this fact, and its impact on the time to core uncovery and core damage, we did not really draw attention to the need to do anything about it.  So long as there were multiple station batteries, multiple onsite emergency diesels, and multiple off-site power feeds (which was the case at Browns Ferry), this just didn’t seem to be a problem.  An event that could take-out all of these power supplies, and keep them out of service for days on end simply wasn’t deemed credible.

The time to initial core uncover following loss of station batteries was not really a surprise as it’s basically a hand calculation.

The small size of the primary containment did attract our attention.  The primary containment (drywell and pressure suppression pool) was sized to handle a large break loss of coolant accident. Given that BWRs only operate around 1000 psi, (rather than 2000 psi as PWRs do), and given that BWRs employ pressure suppression pools to condense steam from such an accident, the BWR containments are much smaller than PWR containments.  However, in the case on an unmitigated long-term station blackout, the small containment size increases the challenge of maintaining primary containment – particularly if the reactor vessel melts through, and even more-so if the reactor is pressurized at the time it melts through.  In our analysis, the impact of the small containment size was reflected as rather rapid containment pressurization and heatup following reactor vessel melt-through – which led to failure of the containment electrical penetration assemblies about 1.5 hours after reactor vessel failure.

Though we did not identify it in 1981, in the following years, the possibility of a unique BWR MK-I severe accident containment failure mechanism was identified and extensively studied.  Basically, it had to do with the possibility that due to the small size of the drywell, after reactor vessel melt-through, molten core/concrete debris might possibly contact and fail the steel drywell liner that constitutes the primary containment shell.  The probably of this failure mechanism was determined to be plant specific, and it was ultimately determined that the probability of this failure occurring was very low if there was just several inches of water on the drywell floor during this phase of the accident. 

Relative to the ECCS design, the 1981 study did identify some changes to the HPCI/RCIC system that would reduce the probability of their failure during the station blackout event.

Our 1981 study really did not look at hydrogen explosions, though we did note that several hundred kilograms of hydrogen were generated during the accident.  We terminated the analysis when the primary containment failed.  However, in subsequent analysis over the next several years, we devoted considerable attention to the behavior of hydrogen once it escaped into the reactor building.  We looked in detail at hydrogen burns and detonations in the reactor building, and the likely response of the reactor building to such events.  The moment I saw the video of the first explosion at Fukushima, I turned to my wife and said, “They’ve had a hydrogen explosion in the reactor building.”

QUESTION 4.     In 1976, three engineers left GE calling for shut down of Mark 1 plants and demanded to take necessary steps to ensure the safety of the nuclear reactors. They claimed that Mark 1 has design problems.  How did you think of their claims?

I am not familiar with that situation nor their claims, so I really cannot comment on it. 

QUESTION 5.     GE3 evaluated Mark 1 "the most dangerous" plants.  How do you think of their assessment as a person who did SBO sequence analysis?


I am not familiar with that situation, so I cannot comment on it. 

The BWR severe accident studies continued at ORNL for almost twenty years.  Also, and more importantly, the NRC issued a requirement in 1988 that every U.S. nuclear plant conducted a so-called “Individual Plant Examination” or “IPE”.  The IPE’s were designed to systematically examine each plant’s vulnerability to severe accidents. NRC summarized the overall insights from these IPEs in NUREG-1560 in late 1997.

It is the case that, taken as a whole, the IPEs completed in the 1990s indicated that BWR Mk-I plants were, in general, somewhat more likely to fail during a severe accident than later Mk-II or Mark-III designs. 

However, there was considerable “scatter” in the estimated severe-accident induced containment failure probabilities for all BWR and PWR containment designs, and there was considerable overlap in the calculated containment system failure rates for plants of all types.

The IPE studies also found that PWR containments were somewhat more vulnerable than BWR containments to containment isolation failures during severe accidents – that is, containment leakage through existing pathways – rather than damage to the containment structure itself.

Perhaps most importantly, the IPE’s collectively indicated there was no significant difference between the probability an early large release of radioactivity during severe accidents in a BWR Mk-I plants and other BWRs and PWRs.

So, taken in total, there was no basis from the IPE studies to conclude Mk-I plants presented an unacceptable level of safety.

(REFERENCE: U. S. Nuclear Regulatory Commission NUREG-1560, Vols. 1-5, "Individual Plant Examination Program: Perspectives on Reactor Safety and Plant Performance," Final Report, December 1997.)

QUESTION 6.     Did you have any recommendations to make Browns Ferry/Mark 1 safer?

Three key insights from that first study were the benefit of:

  • changing the HPCI/RCIC system operating logic for selecting its emergency water source during the station blackout;
  • changing the operating procedures to allow the reactor operator to take manual control of the reactor safety relief valves to assure the heat from the reactor was distributed evening around the pressure suppression pool so as to avoid containment over-pressurization;
  • modifiying the emergency operating procedures to assure the reactor operators depressurized the reactor vessel prior to significant core damage and reactor vessel failure.

A number of follow-on studies over more than twenty years, identified a several opportunities to improve the ability of the plants to cope with beyond-design-basis severe accidents.  These opportunities generally fell into three categories:

  •  changes in operator actions
  •  modifications to existing plant systems, and
  • addition of new systems.

Operating procedure insights that emerged during those years included changes relating to control of reactor water inventory, containment venting, and drywell flooding, among others.

Several potential plant modifications were identified including: modification to the containment venting system; addition of backup power or pneumatic air supply to various existing reactor and containment cooling systems; the addition of dedicated containment flooding systems; and small, but important modifications to the reactor support skirt to enhance the effectiveness of containment flooding in cooling the reactor vessel.

QUESTION 7.     How did you feel when you first heard about Fukushima Daiichi incident?

My first response was one of shock at the size of the earthquake and the resulting tsunami, and deep regret for the death, destruction and damage the quake and tsunami had caused throughout Japan.

With regard to the Fukushima Dai-Ichi plant, my immediate response was typically analytical.  I was wondering:

  •  What was the overall plant damage state – which systems, components, and structures had been damaged by the quake and the tsunami?

  • Where were the emergency diesel generators (EDGs), the EDG fuel supplies, and related switchgear located – and were they accessible and functional?

  • What was the station battery lifetime, where were the station batteries and their associated switchgear located – and were they accessible and functional?

  • What were the Fukushima Dai-Ichi Emergency Procedure Guidelines and Severe Accident Management Guidelines for such events?

As I said before, I knew the moment I saw the video of the first explosion that there had been a hydrogen detonation in the reactor building.  That would have been an obvious conclusion for anyone who had studied these types of accidents.

QUESTION 8.     Was your SBO study of 1981 used to advantage to improve safety measures?

I believe so. However, our study was but the first of many such analyses performed between 1980 and the late 1990s.There was an intensive effort on the heels of the TMI-II accident in 1979, that lasted for 20 years or longer to understand the accidents, understand how to reduce the vulnerability of the plants to such accidents, and to improve their ability to cope with such accidents should they occur.  Both the NRC and the nuclear industry focused enormous attention on the subject with long-term experimental research, computer code development, and plant-specific accident probabilistic safety assessments (PSA) and individual plant examinations (IPE) analyses.

ORNL, supporting the NRC, focused on BWR severe accidents through the late 1990s.  During that time, ORNL studied all of the “risk-dominant” BWR severe accidents.  A number of emergency operating procedure improvements, severe accident management guideline improvements, and equipment improvements were identified during that time.  A number of them were implemented, though I cannot say which ones were implemented on a plant-specific basis.

QUESTION 9.     Do you know if Japanese government or TEPCO knew about the SBO sequences analysis you did?

I do not know. Again, our study was not the most important – just the first.  I would hope they had some access to the large body of plant-specific BWR PSA and IPE studies done by the NRC and the U.S. nuclear industry – as well as U.S. BWR emergency operating procedures and severe accident management guidelines.

Monday, August 1, 2011

Post # 50: Bill Gates On Sustainable Energy

I subscribe to Wired Magazine.  Every issue contains something that is thought-provoking, imagination stretching, or just plain cool...

Imagine my surprise when I opened up the July issue several weeks ago to find an interview with Bill Gates on the subject of energy.  The article was based, in part on Gates' speech to the Wired Business Conference: Disruptive By Design.

Some rather direct statements by one of the world's most powerful and innovative men...

"If you gave me the choice between picking the next 10 presidents or ensuring that energy is environmentally friendly and a quarter as costly, I'd pick the energy thing."

Question: How has Fukushima changed your perspective on nuclear power?
Answer:  "...The environmental and human damage is clearly very negative, but if you compare that to the number of people that coal or natural gas have killed per kilowatt-hour generated, it's way, way less.  The nuclear industry has this amazing record, even equipment from generations one and two.  But nuclear mishaps tend to come in these big events – Chernobyl, Three Mile Island, and now Fukushima – so it's more visible.  Coal and natural gas have much lower capital costs, and the tend to kill only a few at a time, which is highly preferred by politicians."

Question: ...When you look at the big picture, where should we be focusing besides nuclear?"
Answer:  "If you're going for cuteness, the stuff in the home is the place to go.  It's really kind of cool to have solar panels on your roof.  But if you're really interested in the energy problem, it's those big things in the desert."  (He's talking here about large central-generating solar plants, I presume.)

Question: What about the usage side?  What do you think of the technologies that are increasing efficiency, cutting down on the amount of energy consumed?
Answer: "There's certainly lots of room for increasing efficiency.  But can we, by increasing efficiency, deal with our climate problem?  The answer is basically no."

Question:  "So suffice to say we will find no solar cells on the roof of the Gates residence?
Answer:  "Oh, we like to be cute like everyone.  For rich people, this is OK.  Rich people can do whatever they want."

Other quotes: "Ethanol has nothing to do with reducing carbon dioxide; it's just a form of farm subsidy.

So... checkout the Bill Gates Interview on the Wired Magazine website – and think about the over four billion people in this world who have little or no access to useful energy sources...

Just thinking...

Thursday, July 28, 2011

Post # 49: That's 1 step forward and 2 steps back...

One of my favorite sources of global energy data is BP's Statistical Review of World Energy, published annually.  The 2011 version (which actually reports data from 2010) can be found here.

Some highlights:

1. Global energy consumption grew by 5.6% – the strongest growth since 1973.

2. China's share of global energy consumption was 20.3%.  The U.S. share was 19.0%

3. Total global oil consumption grew by 3.1% – the smallest consumption growth of all the fossil fuels.

4.  Global natural gas consumption grew by 7.4% – the strongest growth since 1984.

5.  Coal accounted for 29.6% of global energy consumption – the highest percentage since 1970.  China's share of global coal consumption was 48.2%

6.  Renewable energy consumption accounted for just 1.8% of global energy consumption, but U.S. renewable energy consumption grew by 16.3% from 2009 to 2010.

7.  Global hydroelectricity consumption grew by 5.3%, but U.S. hydroelectricity consumption dropped by 6.0%.

8.  Global nuclear energy consumption grew by only 2.0%, and just 1.0% in the U.S.


We are burning more coal, damming more rivers, burning more natural gas, and straining to maintain our nuclear energy production.

Burning more coal is not a good thing until we can find a way to do it cleanly - from both the carbon capture and storage, and ash management perspectives.

As a conservationist, I'm rarely in favor of damming free-flowing streams and rivers.  I've seen first-hand the archaeological, cultural, and agricultural damage this can do.  I'm in favor of exploring kinetic hydropower.  The jury is still out, but the prospects appear promising.

Natural gas burns more cleanly than coal.  That's good.  The U.S. has significant natural gas reserves.  Problem is, it's down there in a geological "lock box" and a controversial process called "hydrofracking" is currently required to recover it.  See here and here for additional information and views on hydrofracking.  Hydrofracking is definitely one of the technologies at the center of the "energy-water nexus".

I've often said I believe there is no sustainable solution to our global energy problem that doesn't rest upon a major expansion of nuclear energy.  Energy conservation is an appropriate focus for those of us who are part of the 1.5 billion inhabitants of this globe who live in the developed world.  But energy production, and lots of it, is the only option available for the over 4 billion people on this small blue planet who have little or no access to energy - especially electricity.

So there you have it... the view from and Sherrell's sound-bite interpretation of the latest BP Statistical Review of World Energy.

Just thinking,


Tuesday, July 12, 2011

Post # 48: TV-Asahi Interview on BWR Station Blackout

The Fukushima Dai-ichi accident in March of this year, has stimulated a great deal of interest in Japan in the BWR severe accident work done in the U.S. over the past few decades.  In late June, the Japanese television network, tv-asahi sent a team over to interview a number of individuals in the U.S. about that work.  TV-Asahi requested an interview with me to discuss the work done at ORNL on BWR station blackout severe accidents in the early 1980s, with particular interest in the 1981 station blackout report I've discussed in prior posts.  The interview was conducted at ORNL on June 28.  This posting is my prepared pre-interview Q&A script, based on the questions tv-asahi provided me in advance of the interview.  The interview session closely followed this Q&A dialog...

QUESTION: When did you first work on an SBO study?


·      The U.S. Nuclear Regulatory Commission launched the Cooperative Severe Accident Research Program (CSARP) in the wake of the 1979 accident at TMI-2.  CSARP included a variety of R&D activities.  Among them was a focus on detailed systems-level accident sequence analysis for the risk dominant sequences previously identified by the WASH-1400 Reactor Safety Study in 1975.  ORNL was selected by the NRC in 1980 as the lead lab for analysis of Boiling Water Reactor severe accident sequences in a program called the BWR Severe Accident Sequence Analysis (SASA) Program.  Station blackout (which had been identified by WASH-1400 as an risk dominate sequence for BWRs) was selected as the first accident to be analyzed.

·      Independent of NRC activities, the industry launched the Industrial Degraded Core (IDCOR) Rulemaking Program in 1981.  IDCOR ran through about 1989, and included independent code and model development, plant analyses, and experiments funded directly by the nuclear industry. 

QUESTION: What kind of study was it?


·      The 1981 study was the first detailed analysis of the Browns Ferry Unit-1 unmitigated station blackout scenario.  BNFP-1 is a 3440 MWt / 1152 MWe BWR-4/Mk-I plant, larger than Fukushima Dai-Ichi Units 1-5.  We focused on identifying the sequence of events in the accident, the timing of these events, analyzing the role of operator actions and various plant systems and equipment, and identifying uncertainties and unknowns in the analysis.

·      It is important to understand that our analyses were conducted with computer models that were extremely primitive compared with the computer simulation tools we have available today.  Nevertheless, the overall sequence of events developed in the 1981 analysis has held-up as being basically valid through many subsequent analyses since that time.

QUESTION: What was the result of that study? What did you find out?


·      The major accident sequence events and their timings were estimated based on an assumed 4-hr station battery life and some specific assumptions regarding operator actions.  The potential role of the operator in delaying the onset of core damage was identified, along with some system hardware modifications that would be beneficial.

QUESTION: In an SBO event, what are the primary risks a plant eventually faces if not resolved?


·      PROVIDED THERE IS NO OTHER PLANT DAMAGE associated with the event that led to loss of off-site power and on-site power, the plant can recover normally without damage, if on-site or off-site power is restored before the station batteries are exhausted.

·      Assuming a 4-hr battery lifetime, and no special operator actions, core damage would begin between 1 and 2 hours after the batteries are exhausted (~ 6 hours after the initiating event).

·      Unless reactor cooling is restored, the accident sequence would progress through core oxidation, melting and relocation to the lower regions of the reactor vessel.  During the period, a few hundred kg of hydrogen would be produced due to interaction between steam and the over-heated fuel assemblies.  Eventually, the lower head of the reactor vessel would fail, allowing hot core debris to fall onto the concrete floor of the primary containment “drywell”, where it would interact with the concrete, releasing more hydrogen, other non-condensible gases, and steam.  Along the way, various radioactive materials would be released into the primary containment (drywell and wetwell).  Eventually, the primary containment would fail due to over-pressure and temperature, releasing its mixture of combustible gases and radioactive material into the surrounding reactor building.

QUESTION: In the case of this hypothetical SBO in the study, what was the sequence of events?  (i.e. _ occurs after 10 minutes, after 30 minutes, _ long until containment failure, _ hours until core meltdown?)


  First few seconds

·      Recalling that our assumption was that other than losing off-site power and on-site diesel generators, the plant was undamaged…

·      Within the first few seconds, the plant senses the loss of power, and vital plant functions transfer their load to the station batteries, which in our case were assumed to last for four hours.

·      The reactor “scrams” or shuts down.  It’s power level drops from 100% power to a few % within seconds and down 2% or so, slowly decaying for hours and days after this point.

·      Normal cooling water to the reactor ceases, and steam flow to the electrical turbines is terminated.  The reactor is “isolated”.

·      The reactor’s safety/relieve valves (SRVs) function automatically as designed to control reactor pressure, but venting steam from the upper regions of the reactor into the pressure suppression pool

  First few minutes

·      The plant’s HPCI and RCIC systems trigger and begin injecting water into the reactor vessel. (The plant we analyzed did not have an isolation condenser.) These systems draw water from a large water storage tank called the “condensate storage tank” which sits outside the reactor building.  Everything is working as designed during this period.

  First 4 hours

·      During the next four hours, up until the station batteries are exhausted, the combined effects of HPCI/RCIC system injection, coupled with SRV actuation, keep the reactor core covered and undamaged.  However, both the pressure suppression pool and the drywell atmosphere are heating up and slowly pressurizing.  The plant could recover normally without damage if power is restored during this period.

 @ 4 hours

·      Station batteries are depleted, and all water injection to the reactor ceases at 4 hours due to the assumed 4-hr battery lifetime.

 4-5 hours

·      The water level in the reactor drops as water is boiling off and the steam is dumped to the pressure suppression pool through the safety relief valves.  The water level drops to the top of the core in approximately 1-hr after battery depletion.

 5-6.5 hours

·      The core begins to overheat as the water level in the reactor continues to drop below the top of the fuel.  The fuel heats up, and various fuel assembly and control plate materials interact with the hot steam releasing a few hundred kg of hydrogen into the reactor and (via the safety/relief valves) into the pressure suppression pool.  The different core components and materials overheat and melt at different temperatures, but the overall effect is for the core to melt and relocate downward into the lower regions of the reactor vessel – ultimately interacting with the lower head of the reactor vessel and the various penetrations in the lower head.

 @ 7 hr

·      The bottom head of the reactor vessel fails due attack from the hot core debris inside the reactor vessel

 7 – 8.5 hr

·      Molten core debris escapes the reactor vessel and falls upon the concrete floor of the primary containment drywell.

·      The hot core debris interacts with the drywell floor concrete, releasing steam, a variety of non-condensible gases, and radioactive aerosols (smoke) into the drywell atmosphere.

·      The primary containment drywell pressure and temperature increase due to the effects of the core-concrete interactions

@ 8.5 hr

·      The flexible seals in the primary containment drywell electrical penetrations fail due to the combined effect of high pressure and high temperature.

 It should be noted that the timings of major sequence events (such as core uncovery, reactor vessel failure, etc.) are very sensitive to the assumed battery life and key assumptions about operator actions to depressurize the reactor.  I recall a later re-analyses of the SBO sequence with an assumed battery life of 6-hr rather than 4-hr, and with an assumption the operators take steps to depressurize the reactor.  Reactor core uncovery time for that sequence was estimated to be delayed until ~ 10.5 hrs (rather than 5 hrs), and reactor vessel failure was estimated to be delayed till ~ 15.5 hrs after the initiation of the event (rather than 7 hrs).

QUESTION: What system safeguards are critical to deal with an SBO event?  What do you think about what countermeasures or coping measures are needed in this scenario?


·     The specific answers to the question will vary from plant to plant.  In general, the functions that must be maintained are reactor core and containment cooling to avoid core damage and containment failure.

·      In general, the following types of countermeasures can help assure the key reactor and containment cooling functions are maintained:

o  Assured power supply: multiple off-site power feedlines to the plant, multiple emergency diesel generators with secure fuel sources, and multiple, long-life station batteries, combined with the ability to physically import units from off-site when/if needed.  The physical placement of these resources on-site, and the manner and location in which they are interfaced with and connect to the power plant are also important.

o  Assured cooling water supply: a secure, large condensate storage tank capable of supplying water to the HPCI/RCIC system for extended periods (this was not an issue in our SBO analyses).  Alternatively, dedicated diesel-powered portable pumps can be staged to provide this function from other water sources.

o  Assured reactor vessel pressure control: Reactor vessel depressurization has been shown to be a very useful severe accident mitigation technology.  SRV operability is essential to accomplish such depressurizations.  An assured control air supply is required to maintain SRV operability for the long periods of time involved in an SBO.  This can be provided by secure bottled gas systems.

o  Assured containment cooling: A secure means of cooling the primary containment pressure suppression pool and drywell atmosphere under SBO conditions. A number of options are possible, but the use of diesel-driven RHR pumps and drywell coolers powered by backup power systems are options.

o  Assured containment pressure control: the ability to vent the primary containment if necessary to relieve containment pressure while scrubbing radioactive material from the vented gas and avoiding hydrogen explosions is very important.

o  Remedial reactor vessel cooling and debris cooling: the ability to flood the primary containment with water up to about 2/3 the height of the reactor vessel, coupled with simple modifications to the reactor support skirt, can be effective in preventing reactor vessel failure and cooling any core debris that escapes the reactor.

o  Assured station condition monitoring: Instrumentation that continues to function in an SBO to provide the operators critical information about the state of the reactor, containment, and critical systems.

o  Assured operator preparedness: The power plant operators can play critical roles in managing the accident.  Realistic, focused training of the operators to cope with the real-life circumstances to be expected in an SBO is essential.

 All of these insights emerged from the work performed 1975 and 2000.

QUESTION: How do you feel about the dangers of an SBO?


·       Numerous studies have shown the importance of SBO as a contributor to the overall risk profile of commercial BWR nuclear plants.  During the past thirty years, nuclear plant designers, regulators, operators here in the U.S. have devoted a great deal of attention to this fact and have taken a number of actions to respond accordingly.  Nevertheless, the Fukushima Dai-Ichi accident demonstrates there’s more work to be done.  The nuclear industry must and will learn and improve from this unfortunate event.