Post # 45: Whose Got The Oil?

I recently participated in 15th International Conference on Emerging Nuclear Energy Systems (ICENES-2011) in San Francisco, California.  I presented a paper on the status of fluoride salt-cooled reactor concepts and their enabling technologies (more about this in a later post).

At the meeting,  Dr. Charles Forsberg (formerly of ORNL and now with MIT), presented a fascinating analysis of the challenge associated with harmonizing the time-dependent dynamics U.S. electricity production and the time-dependent electricity demand.  Charles proposes a large-scale nuclear-geothermal energy production and geological storage approach that is really interesting (more about this in a future post as well).

But one of the elements of Charles' presentation that really grabbed my attention was his analysis of the vulnerability of the U.S. petroleum supply.  I want to draw your attention to it as well.

If you want (another) reason to ring your hands over our energy dependency and the un-sustainable vector we are on, take a look at this:

http://www.petrostrategies.org/Links/worlds_largest_oil_and_gas_companies.htm

The data there, based on information from The Oil and Gas Journal, Sept. 15, 2010 demonstrates the absolute control a handful of nations have over the world's oil supply.


Here's the bottom-line: the total equivalent reserves of the top four oil companies/nations  (~936 Billion equivalent barrels) exceeds the COMBINED reserves of the next 46 companies (~ 846 Billion equivalent barrels by my count).


Who are these "four horseman" of the fossil fuel world?  

Iran, 

Saudi Arabia, 

Qatar, and 

Iraq

Where does Exxon Mobile rank?  Exxon comes in at #14 with only 15 Billion barrels.

BP you ask?  BP just manages to reach #18 on the list with only 13 Billion barrels.

Just for comparison,  the U.S. Energy Information Agency @ ( http://www.eia.gov/energyexplained/index.cfm?page=oil_home#tab2 ) indicates the U.S. consumed just under 19 million barrels of oil per day in 2009, importing just under 10 million barrels per day – just over 50% of our daily oil consumption.

That's not sustainable...

Just thinking,
Sherrell

Post # 44: The Carbon Footprint Of Electricity Production - Time Value of Carbon Offsets

Several days ago I had the pleasure lunching with Gregg Marland, a colleague of mine at ORNL.  Well, actually Gregg recently retired from ORNL and is now with Appalachian State University's Institute for Environment, Energy, and Economics ( http://rieee.appstate.edu/ ).  Gregg is a long-time protege of the late Dr. Alvin Weinberg and is well know in the climate research and carbon cycle research community.  See for instance, http://pages.csam.montclair.edu/pri/pdf/science4.pdf , and  http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1240257/pdf/ehp0109-a00124.pdf ).  He has researched and written extensively on the topic of carbon offsets and the dynamics of carbon offsets.

The idea of carbon offset dynamics probably should have, but really never had crossed my mind until I met with Gregg.  Imagine a carbon management framework in which one can purchase or barter carbon emissions offsets (say from planting a forest as a carbon sink) to counter carbon emissions stemming from an industrial activity (say manufacturing, energy production, etc.).   The issue stems from the fact that the time-dependent nature of the carbon emissions from the industrial activity is not the same as the carbon sink from the forest.  The carbon emissions come in the short-term and continue at a rate and for a period of time dependent upon the nature of the industrial activity.  However, the "off-setting" carbon sink builds through time and, (at least theoretically) could continue indefinitely - long after the industrial activity terminates.  This is, of course, unless the terms of the offset agreement allows the forest owner to harvest or "cash-in" their carbon credits at some point in time.

Anyway, this scenario raises the question, "What is the time-value or "discount rate" of time-dependent carbon offsets?  The question touches upon inter-generational equity issues similar to those I've discussed here before.  It raises the question of appropriate time-frame for the analysis.  How does one determine the appropriate time frame for the analysis?  Is it simply the period of a business agreement?  A human generation?  A human lifetime?  Several lifetimes?  What about the geological timeframe?

And what if there's a tipping point somewhere out there in the future such that the value of carbon offsets prior to the tipping point is very high, but very low after the tipping point occurs?   (I'm thinking here of scenarios such as ice cap melting, burst release of carbon dioxide due to the melting of frozen tundra, ocean turnover, etc.)

And then it struck me that the burning of fossil fuels for energy production is an interesting example of a very-longer term release or "redemption" of carbon credits or offsets.  Obviously, a hugh inventory of carbon was sequestered as the world's coal reserves were formed over geological time.  Now, we're redeeming those carbon credits in in exchange for the energy we derive from burning the fossil fuels from which they derived.

Why does all of this matter?  Because it is issues such as this that impact the dialog about the value of carbon credits (or alternatively, the rate set for carbon "taxes"), and the development of regulatory frameworks in which credits and taxes are utilized as management devices.  These issues, in turn, have the ability to significantly impact the "break-even" economics of various energy generation technologies.

Enough said for now about the topic, but it's one all of us who care about sustainable energy would do well to understand better.

Thanks to Gregg for alerting me to the topic.  I find it very interesting and hope you do as well.

Just thinking....
Sherrell

Post # 43: Fukushima, Defense-In-Depth, and Risk-Based-Regulation

I'll begin this post by posing a provocative question:

Does the Fukushima Dai-Ichi accident demonstrate the supremacy of "defense-in-depth" over "risk-based regulation" ?  Or put differently, "Is Fukushima an indictment of risk-based reactor safety regulation?"

Five minutes before the devastating earthquake shook Japan on March 11, neither a richter 9 earthquake or a 15 meter tsunami were considered to be "credible" events. Yet they both occurred.  Whether due to bad data, mis-interpretation of data, or poor risk methodology, almost everyone was caught "flat-footed" by the historic event.

The devastation unleashed upon Japan and the Japanese people by the quake and the resulting tsunami was horrific.

Fukushima Dai-Ichi was designed to withstand neither event.  The damage to four of the six units was extreme.  Yet, to this point in time, the reactors and primary containments in units 1-3 have apparently avoided gross energetic failures (not so the refueling pools and secondary containments, but that's another story).  I'm not minimizing the severity of the accident or it's off-site consequences – just acknowledging that matters could have been even worse.  Why aren't they?

The answer is due in large part to good old-fashioned "defense-in-depth".

Defense-in-depth is a traditional reactor safety design philosophy that integrates multiple engineered barriers and redundant layers of defense to compensate for mechanical and human failures so that no single barrier is relied upon to protect against an accident.  An example is that radioactive fission products are contained in the fuel, which is inside the fuel cladding, which is inside the reactor vessel, which is inside the primary containment, which is inside the secondary containment.   For those unfamiliar with the principle, see NRC's discussion of the topic here and here.

Many things went wrong at Fukushima, yet the engineers who designed the plant (prior to the era of risk-based regulation) incorporated a number of conservative assumptions, defense-in-depth design strategies, and robust design margins that have, until now, prevented the accident at Fukushima Dai-Ichi from evolving to a much more dire situation.

So back to my question...The truth is that risk-based regulation, properly applied, should result in designs more capable of withstanding the threats we expect them to face during their operating lifetimes.  This is good – but not sufficient.  Fukushima confirms our need for a healthy dose of humility when it comes to quantifying "credible" events.

Defense-in-depth and risk-based regulatory approaches complement each other.  Call it the "belt and suspenders" approach.  Fukushima confirms the importance of this approach.

So, when it comes to reactor safety, I'm a "belt and suspenders" man.  And so should we all be who are serious about nuclear energy and a sustainable energy future.

Just thinking...

Sherrell

Post # 42: Early BWR Station Blackout Severe Accident Analyses

I've noted back in Post # 31 that unmitigated BWR severe accident sequences similar to the recent Fukushima Dai-Ichi event were analyzed as early as 1981 at Oak Ridge National Laboratory.  Several folks have asked me if the original NUREG/CR reports for the two original Oak Ridge analyses were available.  I've located them and uploaded them here.

The first report is the original 1981 report in which the unmitigated long-term station blackout sequence for Browns Ferry nuclear plant (a BWR-4 / Mark-I) was analyzed:

NUREG_CR_2182_Vol_1

Recall the "long-term" qualifier implies that, while the accident sequence assumptions assumed both off-site power and on-site station diesel generators were unavailable from the on-set of the event, the station batteries were assumed available until they were exhausted four hours or longer after accident initiation.

In 1982, ORNL released a second companion report in which the fission product transport phenomenology for the Browns Ferry long-term station blackout sequence was evaluated:

NUREG_CR_2182_V2

I caution everyone that these were the original analyses, performed with a suite of computer codes and models (accident progression and fission product transport) that were primitive by today's standards.  Additionally, Browns Ferry is a larger plant than Fukushima, and had a shorter station battery life.  

In subsequent years, ORNL analyzed other station blackout and loss-of-decay heat removal sequences in BWRs, developed more advanced tools for invessel accident sequence analysis (the BWRSAR code, developed by  Larry Ott is particularly notable), and worked closely with Sandia National Laboratory to develop BWR modeling approaches for the MELCOR code.

In 1994, one of our colleagues, I. K. Madni, then at Brookhaven National Laboratory, performed a similar long-term station blackout analysis with MELCOR for the Peach Bottom plant (another BWR-4/Mk-I plant):

NUREG_CR_5850

While I cannot go into all of the details here, a close read of these reports will aptly demonstrate the significant influence station battery lifetime, automatic safety system operating logic protocols, and manual operator actions can have on key accident event timings.


Just thinking...
Sherrell

Post # 41: Fukushima – A Black Swan For Nuclear Energy?

Many of you may be familiar with Nassim Nicholas Taleb's recent best selling book, "The Black Swan".  In his book Taleb defines a "Black Swan Event", as an unexpected / rare event with large consequences that changes the course of history.  He lays out three defining Black Swan Event criteria that Wikipedia summarizes as:


1. The event is a surprise (to the observer)
2. The event has a major impact
3. After it's first recording, the event is rationalized by hindsight as if it could have been expected (e.g. the relevant data were available but not accounted for)


Taleb's book is a dialog about robustness and fragility in systems.  Post Fukushima, I've been thinking about robustness and fragility in our present energy system and in any sustainable energy system of the future.  I'm concerned about the utter dependence, in my view of sustainable energy paradigms on the successful growth and deployment of nuclear energy.


So, I ask, "Is the Fukushima Dai-Ichi event a "Black Swan Event" for nuclear energy?"


It certainly was a surprise (Criteria # 1): Back-to-back beyond design basis earthquake and tsunami


It was / is a major event (Criteria 2): Category 7 on the IAEA INES scale


With respect to Criteria # 3, many are pointing out the (now obvious) observation that accidents in one unit at a multi-unit nuclear plant site can impact other units and complicate access to the units following the initiating event.   Similarly, it seems rather obvious that storing highly radioactive used/spent nuclear fuel in close proximity to the reactor may not be the best choice.... I could go on, but these two observations are sufficient to illustrate the point. 


Looks like a Black Swan to me...


But will it change our approach to nuclear power?  Will we evolve to nuclear power systems that are more robust and less fragile?   How about sustainable energy systems that are robust?  What does that look like?


Just thinking...

Post # 40: Mitigating BWR Station Blackout Accidents – Foundation Documents

During the past month there's been a great deal of discussion in the media, here on the internet, and elsewhere, regarding possible approaches to halting the accident progression at Fuskushimi Dai-Ichi and stabilizing Units 1-3.  As I've previously mentioned, there was a significant amount of work done in this area in the 1980s through the late 1990s.  Steve Hodge and his colleagues at ORNL performed a detailed analysis of various approaches to terminating the station blackout severe accident progression, in conjunction with the BWR Owners Group Emergency Operating Procedures then in effect.  Steve and company looked at both "early-phase" (pre-core-damage), and "late-phase" (post-core-damage) strategies.  Based in large part on their work, the Emergency Operating Procedures and Severe Accident Management strategies then in effect were modified.


The first document is "Assessment of Two BWR Accident Management Strategies,"CONF-911079-2, by Hodge and Petek.  You can find it here:  Conf 911079--2


Quoting from the abstract of the document, ,  "Candidate mitigative strategies for management of in-vessel events during the late phase (after core degradation has occurred) of postulated BWR severe accidents were considered at Oak Ridge National Laboratory (ORNL) during 1990. The identification of new strategies was subject to the constraint that they should, to the maximum extent possible, make use of the existing equipment and water resources of the BWR facilities and not require major equipment modifications or additions. As a result of this effort, two of these candidate strategies were recommended for additional assessment. The first is a strategy for containment flooding to maintain the core and structural debris within the reactor vessel in the event that vessel injection cannot be restored to terminate a severe accident sequence. The second strategy pertains to the opposite case, for which vessel injection would be restored after control blade melting had begun; its purpose is to provide an injection source of borated water at the concentration necessary to preclude criticality upon recovering a damaged BWR core. Assessments of these two strategies have been performed during 1991 under the auspices of the Detailed Assessment of BWR In-Vessel Strategies Program. This paper provides a discussion of the motivation for and purpose of these strategies and the potential for their success."

The second document is the definitive analysis, "Identification and Assessment of BWR In-Vessel Severe Accident Mitigation Strategies", NUREG/CR-5869, by Hodge, Cleveland, Kress, and Petek.  I've uploaded the entire report here: Cr 5869


Quoting from the abstract of NUREG/CR-5986:  "This report provides the results of work carried out in support of the U.S. Nuclear Regulatory Commission Accident Management Research Program to develop a technical basis for evaluating the effectiveness and feasibility of current and proposed strategies for boiling water reactor (BWR) severe accident management.  First, the findings of an assessment of the current status of accident management strategies for the mitigation of in-vessel events for BWR severe accident sequences are described. This includes a review of the BWR Owners' Group Emergency Procedure Guidelines (EPGs) to detennine the extent to which they currently address the characteristic events of an unmitigated severe accident and to provide the basis for recommendations for enhancement of accident management procedures. Second, where considered necessary, new candidate accident management strategies are proposed for mitigation of the late-phase (after core damage has occurred) events. Finally,  recommendations are made for consideration of additional strategies where warranted. and two of the four candidate strategies identified by this effort are assessed in detail: (1) preparation of a boron solution for reactor vessel refill should control blade damage occur  during a period of temporary core dryout and (2) containment flooding to maintain the core debris within the reactor vessel if the injection systems cannot be restored."

These are both very technical documents (especially the NUREG), but give the amount of interest and dialog about the topic, I felt it would be appropriate to make these two public documents a bit more accessible...


For those of you who are wondering... I do plan to return to my central theme - sustainable energy – very soon.  However, given recent events in Japan, and their relevance to the anchor of a sustainable energy future (nuclear power), I feel it important to focus on the BWR severe accident safety topic for a bit.


Just thinking...

Post # 39: Learning From Fukushima

I've made it clear I see no sustainable energy solution apart from relying on nuclear energy for the majority of our base load electrical power generation.   So how, in the long-term,  will we respond to Fukushima?

Short Answer:  The nuclear power industry and nuclear safety regulators will learn and improve. 

The "plan"?

First:  UNDERSTAND WHAT happened at Fukushima.

Second: UNDERSTAND WHY the accident evolved in the manner it did.

Third: UNDERSTAND if and if-so, HOW existing nuclear plants should be modified and future nuclear plants should be designed to cope better with such accidents.

Fourth: COMMIT and ACT upon this new knowledge.

I remember the accident at Three Mile Island (TMI) – which, by the way, was not as severe as the Fukushima event.   I remember how the nuclear industry and nuclear safety regulators mounted a tremendous effort to understand that accident.  I remember that knowledge changed nuclear power – for the better.  New nuclear plant designs such as the AP-1000 and the ESBWR rely much more on passive safety systems for ultimate safety functions.  They have much longer battery life.  The nuclear power licensing process now requires plant designers and owner/operators to consider "Beyond Design Basis" accidents in a manner not considered prior to TMI.

And like TMI,  Fukushima will drive a new era of self-examination, fresh thinking, and safety improvements in commercial nuclear power. 

The learning process has already begun, as William Levis, President and Chief Operating Officer of PSEG Power LLC recently testified before a Senate committee.  Here are a few of my crystal ball predictions regarding some of the impacts of the Fukushima Dai-Ichi events in the months and years to come:

1.  Fukushima will change the way we define common-cause "Beyond Design Basis Accidents".  Fukushima demonstrates that "mega-events" are possible.   "Improbable" is not "impossible".

I defined a mega-event or "Fukushima-like event" in Post # 35, as an event that damages multiple reactor units, compromises an entire nuclear plant site, and negates the ability of the surrounding region to render assistance to the plant.  Generally speaking, such events have not been considered credible in previous reactor safety/risk assessments because the probability of such events has been considered to be below the threshold for consideration.  (Technically, the probability of such events may still be vanishingly-small.  But now one has occurred.)   Here are some examples of potential Fukushima-like events:  

• An earthquake that leads to the breach of an upstream dam, that leads to a super-flood.
• An earthquake that destroys the heat removal function of the plant – either by collapsing cooling towers or cooling water inlet structures.
• A flood that leads to the breach of an upstream dam, that leads to a super-flood
• A super-solar flare leading to and EMP-like pulse that damages the electrical grid and systems attached to it 

2. Fukushima will catalyze R&D focused on the development of new light water reactor fuel systems that would be less susceptible to over-heating, cladding oxidation / hydrogen production, and severe damage in the event of a Fukushima-like accident than current generation commercial nuclear fuels.


3. Fukushima will catalyze a re-examination of "life-beyond-sixty" or nuclear plant life extension.  The question will be posed, "IF newer plant designs are less vulnerable to Fukushima-like events, shouldn't we replace older plants with newer ones, rather than continuing to operate the older plants?"  This will be a vigorous cost vs. benefit debate when an older plant is providing cheap electricity for it's rate payers and generating $2M/day in profits for its owners...

4. Fukushima will catalyze a re-examination of, and ultimately a requirement for, longer station battery lifetime in nuclear plants.  Four, six, or even eight hours will not be considered sufficient.  (This actually isn't a prediction.  The dialog has already begun.  See: http://www.wnyc.org/npr_articles/2011/mar/31/the-future-of-nuclear-energy-in-the-us/transcript/ .)

5. Fukushima will change emergency response planning for nuclear power plant accidents.  The dialog regarding emergency planning zone (EPZ) sizes will be revisited.  The case for smaller EPZs for small modular nuclear plants (SMRs) will be given greater scrutiny.  

These dialogs will be vigorous, passionate, controversial, and healthy for nuclear power and society.  Like Alvin Weinberg, I believe the nuclear power enterprise bears a special responsibility to warrant, maintain and strengthen the trust and confidence of the public.  And I'm confident the nuclear power industry and nuclear safety regulators are up to the challenge.

Just thinking...