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...

Post # 38: My Publications

Some of you know that I've been in the nuclear energy, science, and technology R&D world for over three decades.  During that time, I've published a number of reports, professional presentations, journal articles, etc.  Here's a "relatively-complete" listing...

Energy Parks and Energy Infrastructure

W. C. Jochem, G. T. Mays, Randy Belles, S. R. Greene, et al, National Site Suitability and Spatial Modeling of Electrical Generation Sources, Annual Meeting of the Association of American Geographers, Washington, D.C., April 2010.

S. R. Greene, The Energy Enterprise – An Energy Park Concept for the 21^st Century, American Institute of Chemical Engineers, Nashville, TN, November 2009.

S. R. Greene, Centurion Reactors – Achieving Commercial Power Reactors with 100+ Year Operating Lifetimes, American Nuclear Society Winter Meeting, Washington, DC, November 2009.

G. T. Mays, W. C. Jochem, S. R. Greene, R. J. Belles, M. S. Cetiner, and S. W. Hadley, Identifying and Characterizing Candidate Areas for Siting New Nuclear Capacity in the United States, American Nuclear Society Winter Meeting, Washington, DC, November 2009.

S. R. Greene, G. T. Mays, Development of a Siting Decision Tool for Identifying and Characterizing Potential Electrical Generation Sites, 33^rd Governor’s Conference on the Environment – Empowering Our Future, Lexington, KY, October 2009.

S. R. Greene, “The Tennessee Valley Energy Enterprise – A Sustainable Energy Park Concept,” Chattanooga Technology Council meeting, June 2009.

M. Crozat, S. R. Greene, and R. Roser, Building an “Open Source” Flexible and Extendible Energy Enterprise Model, Proceedings of the Workshop on Science Based Nuclear Energy Systems Enabled by Advanced Modeling and Simulation at the Extreme Scale Conference, U.S. Department of Energy’s Offices of Science and Nuclear Energy, Washington, DC, May 2009.

S. R. Greene, G. F. Flanagan, and A. P. Borole, Integration of Biorefineries and Nuclear Cogeneration Power Plants – A Preliminary Analysis, ORNL/TM-2008/102, Oak Ridge National Laboratory, Oak Ridge, TN, March 2009.

S. R. Greene, A. P. Borole, and G. F. Flanagan, Technology, Process, and Plant-Level Issues Associated with Integration of Nuclear Cogeneration Plants and Biorefineries, American Nuclear Society Winter Meeting, 2008.

S. R. Greene, PICES – A Computer Code for Evaluation of Electric Utility Static Generation Reliability, ORNL-5739, Oak Ridge National Laboratory, August 1981.

M. A. Kuliasha, S. R. Greene, and W. P. Poore, Determining Appropriate Levels of Generation System Reliability, The National Electric Reliability Study:  Technical Study Reports, DOE/EP-0005, U. S. Department of Energy, April 1981.

Boiling Water Severe Accident Analysis and Miscellaneous Reactor Safety

Sherrell R. Greene, "The Canary, The Ostrich, and The Black Swan: A Historical Perspective On Our Understanding of BWR Severe Accidents and Their Mitigation," Nuclear Technology, 186, 115-138 (2014); http://dx.doi.org/10.13182/NT13-44

Juan Carbajo and Sherrell R. Greene, Containment Failure Time and Mode for a Low-Pressure Short-Term Station Blackout in a BWR-4 with Mark-III Containment, Proceedings of the American Nuclear Society Winter Meeting, San Francisco, CA, November 1993.

S. R. Greene, et al., Long Range Research and Development Plan – Reactor-Based Technologies, Rev. 1, ORNL/MD/LTR-12, Oak Ridge National Laboratory,1993.

S. R. Greene, R. T. Primm, et al., Compilation of Plutonium Disposition Reactor Fuel Specifications, Rev. 0, ORNL/MD/LTR-1, Oak Ridge National Laboratory, 1993.

R. H. Morris, S. E. Fisher, S. R. Greene, MELCOR Simulation of a Large-Break LOCA At the High Flux Isotope Reactor, CONF-930601, Transactions of the American Nuclear Society, Vol. 68, 1993.

S. R. Greene, D. G. Morris, R. H. Morris, B. W. Patton, and D. B Simpson, HFIR MELCOR Severe Accident Analysis Model Version 1.0.0 Validation, ORNL/CF-284, Oak Ridge National Laboratory.

P. T. Rhoads, Greene, S. R., Definition of the Existing Light-Water Reactor (LWR) Alternative and Variants, ORNL/MD/LTR-22, Oak Ridge National Laboratory, 1993.

S. R. Greene et al., MELCOR 1.8.2 Assessment:  Comparison of Fuel Fission Product Release Models to ORNL VI Fuel Fission Product Release Experiment, ORNL/NRC/LTR-94/34, 1993.

C. R. Hyman, R. L. Sanders, S. R. Greene, and S. A. Hodge, MELCOR Modifications for SBWR Applications, Proceedings of the Twentieth Water Reactor Safety Information Meeting, Bethesda, MD, 1992.

S. E. Fisher and S. R. Greene, A Preliminary Assessment of Hydrogen Deflagration Issues for the High Flux Isotopes Reactor, ORNL/TM-2395, Oak Ridge National Laboratory, October 1992.

S. R. Greene, S. A. Hodge, C. R. Hyman, and R. L. Sanders, An Assessment of MELCOR Modeling Modifications Required for the Simplified Boiling Water Reactor, ORNL/NRC/LTR-92/11, Oak Ridge National Laboratory, May 1992.

C. R. Hyman, R. P. Taleyarkhan, and S. R. Greene, Characterization of Debris/Concrete Interactions for Advanced Research Reactors and Commercial BWR Severe Accidents, CONF-911107—30, American Nuclear Society Winter Meeting, 1991.

C. R. Hyman, R. P. Taleyarkhan, and S. R. Greene, Characterization of Debris/Concrete Interactions for Commercial BWR Mark II and Research Reactors Severe Accidents, National Heat Transfer Conference, Minneapolis, MN, 1991.

C. R. Hyman, R. P. Taleyarkhan, and S. R. Greene, Characterization of Debris/Concrete Interactions for Advanced Research Reactor and Commercial BWR Severe Accidents, Proceedings for the American Nuclear Society Winter Meeting, 1991.

S. R. Greene, A. E. Levin, C. R. Hyman, A. Sozer, and R. P. Taleyarkhan, BWR Mark II Ex-Vessel Corium Interaction Analyses, NUREG/CR-5623, ORNL/TM-11644, Oak Ridge National Laboratory, November 1991.

S. R. Greene, S. A. Hodge, C. R. Hyman, B. W. Patton, and M. L. Tobias, The Response of BWR Mark III Containments to Short-term Station Blackout Severe Accident Sequences, NUREG/CR-5571, ORNL/TM-11549, Oak Ridge National Laboratory, June 1991.

D. B. Simpson and S. R. Greene, Large Break Loss of Coolant Severe Accident Sequences at the HFIR, International Topical Meeting on the Safety, Status and Future of Noncommercial Reactors and Irradiation Facilities, Boise, Idaho, October 1990.

S. R. Greene, “The Role of BWR Secondary Containments In Severe Accident Mitigation: Issues and Insights From Recent Analyses,” Nuclear Engineering and Design, Volume 120, Issue 1, 1 June 1990, Pages 75-86

S. R. Greene, et al., The Response of BWR Mark II and Mark III Containments to Short-Term Station Blackout Severe Accident Sequences, ORNL/NRC/LTR-89/13, Oak Ridge National Laboratory, 1990.

S. R. Greene and D. B. Simpson, Severe Accident Analysis at the High Flux Isotope Reactor, American Nuclear Society Annual Meeting, Nashville, TN, June 1990.

S. R. Greene, D. B. Simpson, and R. P. Taleyarkhan, A Preliminary Modeling and Analysis Framework- for Severe Accident Analyses of High Power Density Research Reactors, IAEA-SM310/62P, International Symposium on Research Reactor Safety, Operations, and Modifications, Chalk River, Ontario, Canada, October 1989.

S. R. Greene, The Impact of Drywell Shell Melt-Through on Peach Bottom Unit 2 Secondary Containment Survivability, 1988.

S. R. Greene, Supercomputing and Reactor Safety, Vol. 21, No. 3, ORNL Review, Oak Ridge National Laboratory, 1988.

S. R. Greene, Report of the Advanced Neutron Source Safety Workshop, Advanced Neutron Source Severe Accident Analysis Program Overview, CONF-8810193, Knoxville, TN, October 25-26, 1988.

S. R. Greene, The Role of BWR Secondary Containments in Severe Accident Mitigation:  Issues and Insights from Recent Analyses, NUREG/CR-0095, Proceedings of the 4^th Workshop on Containment Integrity, Arlington, VA, June 1988.

S. R. Greene, The Impact of BWR MK I Primary Containment Failure Dynamics on Secondary Containment Integrity, CONF-8710111—6, Transactions of the 15^th Water Reactor Safety Information Meeting, Gaithersburg, MD, October 1987.

S. R. Greene and S. A. Hodge, “ORNL Severe Accident Analysis for 25% Power Operation at the Shoreham Nuclear Power Station,” June 18, 1987.

S. R. Greene, An Assessment of the Shoreham Nuclear Power Station’s Secondary Containment Severe Accident Mitigation Capability, ORNL LTR Report to U.S. Nuclear Regulatory Commission, June 26, 1987.

S. R. Greene, and S. A. Hodge, The Role of BWR MK I Secondary Containments in Severe Accident Mitigation, CONF-8610135—41, Transactions of the 14^th Water Reactor Safety Information Meeting, Gaithersburg, MD, October 1986.

S. R. Greene, NATC – A Simple Model for Analysis of Single-Phase, Water Cooled, Natural Convection Systems, ORNL/CR-85/345, Oak Ridge National Laboratory, December 1985.

S. R. Greene, Realistic Simulation of Severe Accidents in BWRs - Computer Modeling Requirements, NUREG/CR-2940, ORNL/TM-8517, Oak Ridge National Laboratory, 1984.

D. H. Cook, S. R. Greene, R. M. Harrington, and S. A. Hodge, Loss of DHR Sequences at Browns Ferry Unit One - Accident Sequence Analysis, NUREG/CR-2973, ORNL/TM-8532, Oak Ridge National Laboratory, May 1983.

W. A. Condon, R. M. Harrington, S. R. Greene, and S. A. Hodge, SBLOCA Outside Containment at Browns Ferry Unit One – Accident Sequence Analysis, NUREG/CR2672, Volume 1, ORNL/TM-8119/V1, Oak Ridge National Laboratory, November 1982.

S. R. Greene, Improvement of MARCH for BWR Applications, Proceedings of the 10^th Water Reactor Safety Information Meeting, Gaithersburg, MD, October 1982.

S. R. Greene, Application of MARCH to BWR Severe Accident Analysis, Proceedings of the 10^th Water Reactor Safety Information Meeting, Gaithersburg, MD, October 1982.

S. R. Greene, W. A. Condon, and H. L. Dodds Jr., Investigation of Drywell Flooding at the Browns Ferry Nuclear Plant, American Nuclear Society Summer Meeting, Los Angeles, CA, June 1982.

D. H. Cook, R. M. Harrington, S. R. Greene, S. A. Hodge, and D. D. Yue, Station Blackout at Browns Ferry Unit One – Accident Sequence Analysis, NUREG/CR-2182, ORNL/NUREG/TM-455/V1, Oak Ridge National Laboratory, November 1981.

S. R. Greene, The Design, Implementation and Cost-Benefit Analysis of a Dynamic Testing Program in the Experimental Breeder Reactor-II, Master’s Thesis, University of Tennessee, March 1979.

Advanced Reactors

S. R. Greene, SmATHR – the Small Modular Advanced High Temperature Reactor, Infocast 2011 SMR Symposium, Washington, D.C., March 28, 2011.

S. R. Greene, J. C. Gehin, D. E. Holcomb, et al., Pre-Conceptual Design of a Fluoride-Salt Cooled Small Modular Advanced High-Temperature Reactor (SmAHTR), ORNL/TM-2010/199, Oak Ridge National Laboratory, December 2010.

Danut Ilas, Jess C. Gehin, Sherrell R. Greene, Preliminary Nuclear Design Studies for a Small Modular Advanced High-Temperature Reactor (SmAHTR), American Nuclear Society 2010 Winter Meeting, Las Vegas, NV, November 7-11, 2010.

Juan J. Carbajo, Graydon L. Yoder, Sherrell R. Greene, Transient Thermal-Hydraulic Simulation of the Small Modular Advanced High-Temperature Reactor (SmAHTR), American Nuclear Society 2010 Winter Meeting, Las Vegas, NV, November 7-11, 2010.

Sherrell R. Greene, SmAHTR – A Small Modular High-Temperature Reactor, Transactions of the American Nuclear Society, Volume 103, 2010 Winter Meeting, Las Vegas, NV, November 7-11, 2010.

Sherrell R. Greene, David E. Holcomb, Jess C. Gehin, et al., SMAHTR – A Concept for a Small, Modular Advanced High Temperature Reactor, Paper 205, Proceedings of HTR-2010, Prague, Czech Republic, October 18-20, 2010.

S. R. Greene, SmAHTR – the Small Modular Advanced High Temperature Reactor, presentation to Department of Energy, Fluoride Salt High Temperature Reactor Workshop, Oak Ridge National Laboratory, September 20-21, 2010.

S. R. Greene, SmAHTR – the Small Modular Advanced High Temperature Reactor, 4^th Annual Asia-Pacific Nuclear Energy Forum, Berkeley, CA, June 18, 2010, http://bnrc.berkeley.edu/documents/forum-2010/Presentations/F-Session-II-P/Sherrell_Greene_ORNL_Pres.pdf.

S. R. Greene, Fluoride Salt Reactors (FHRs) and the Five Imperatives of Nuclear Energy, Proceedings of the American Nuclear Society Annual Meeting, San Diego, CA, June 2010.

J. C. Cleveland and S. R. Greene, Application of THERMIX-KONVEK Code to Accident Analysis of Modular Pebble Bed High Temperature Reactors (HTRs), NUREG/CR-4694, ORNL/TM 9905, Oak Ridge National Laboratory, Oak Ridge, TN, August 1986.

J. C. Cleveland and S. R. Greene, Application of THERMIX-KONVEK Code to Accident Analyses of Modular Pebble Bed HTRs, ORNL/TM-9905, Oak Ridge National Laboratory, December 1985.

Space Reactors

S. R. Greene, Lessons Learned (?) from 50 Years for U.S. Space Fission Power Development, Paper 1074, Proceedings of the Space Nuclear Conference 2005, American Nuclear Society Annual Meeting, San Diego, CA, June 5-9, 2005.

Louis Qualls, Sherrell R. Greene, Edward Blakeman, Ken W. Childes, PRESTO: Power Reactor for Surface Terminal Operation, Paper 1201, Proceedings of the Space Nuclear Conference 2005, San Diego, CA, June 5-9, 2005.

S. R. Greene et al., Moving Out! – An Integrated Research, Development, and Demonstration Plan (IRDDP) for Space Power and Propulsion Reactor Technology, ORNL/TM-2004/219, Oak Ridge National Laboratory, November 2004.

A. L. Qualls and S. R. Greene, PRESTO:  Power Reactor for Surface Terminal Operations Conceptual Point Design, ORNL/LTR/SRTP/04-13, Oak Ridge National Laboratory, July 2004.

S. R. Greene, Space Fission Power Technology Integrated Research, Development, and Demonstration Plan (IRDDP) Overview, Space Fission Power Programs Review, Albuquerque, NM, July 2004.

S. R. Greene, A. L. Qualls, J. C. Gehin, and E. D. Blakeman, Feasibility Study of the PRESTO Boiling Liquid-Metal/Stirling Engine Power Reactor Concept for Lunar and Martian Surface Applications, ORNL/LTR/SRTP/04-10, Oak Ridge National Laboratory, April 2004.

S. H. Kimm, A. L. Qualls, Sherrell R. Greene, Jeffrey O. Johnson, Development of Optimization Methodology for Space Reactor Power System Design, Space Technology and Applications International Forum ­– STAIF-2004, AIP Conference Proceedings, Vol. 699, Albuquerque NM, February 2004.

M. L. Tinker, A. L. Qualls, Sherrell Greene, et al, Nuclear Electric Vehicle Optimization Toolset (NEVOT): Integrated System Design Using Genetic Algorithms, Space Technology and Applications International Forum ­– STAIF-2004, AIP Conference Proceedings, Vol. 699, Albuquerque NM, February 2004.

A. L. Qualls, E. D. Blakeman, S. R. Greene, et al., Optimization of Space Reactor Power systems Using Genetic Algorithms, Space Technology and Applications International Forum ­– STAIF-2004, AIP Conference Proceedings, Vol. 699, Albuquerque NM, February 2004.

Sherrell R. Greene, A. L. Qualls, PRESTO – A Simple, Compact, Fission Power System For Mars Surface Power Applications, Space Technology and Applications International Forum ­– STAIF-2004, AIP Conference Proceedings, Vol. 699, Albuquerque NM, February 2004.

S. R. Greene et al., Summary of an Interagency NASA/DOE Review of Space Reactor Power System Concepts, ORNL/SR/LTR-2003/001, Oak Ridge National Laboratory, July 2003.

Reactor-Based Plutonium Disposition, Mixed-Oxide (MOX) Fuel Cycles, and Non-Proliferation

M. D. Laughter, C. E. Romano, S. R. Greene et al., Recommendations for Development of an Integrated Nuclear Fuel Cycle Nonproliferation Strategy, ORNL/NTPO/LTR-2010-01, Oak Ridge National Laboratory, March 2010.

S. R. Greene, Reactor-Based Plutonium Disposition:  Opportunities, Options, and Issues, International Symposium on MOX Fuel Cycle Technologies for Medium and Long-term Deployment: Experience, Advances, Trends, ORNL/CP-102975, Vienna, Austria, July 17, 1999.

B. B. Bevard and S. R. Greene, The Thermal Water Reactor-Based Plutonium Disposition Project, VOLGA ’97, Moscow, Russia, Sept. 2, 1997.

S. R. Greene, B. Bevard et al., FMDP Reactor Alternative Summary Report, Vol. 1-Existing LWR Alternative, ORNL/TM-13275/V1, Oak Ridge National Laboratory, September 1996.

S. R. Greene, D. J. Spellman et al., FMDP Reactor Alternative Summary Report, Vol. 2-CANDU Heavy Water Reactor Alternative, ORNL/TM-13275/V2, Oak Ridge National Laboratory, September 1996.

S. R. Greene, S. E. Fisher et al., FMDP Reactor Alternative Summary Report, Vol. 3-Partially Complete LWR Alternative, ORNL/TM-13275/V3, Oak Ridge National Laboratory, September 1996.

S. R. Greene, D. G. O’Connor et al., FMDP Reactor Alternative Summary Report, Vol. 4-Evolutionary LWR Alternative, ORNL/TM-13275/V4, Oak Ridge National Laboratory, September 1996.

B. B. Bevard, S. R. Greene, et al., Water Reactors Report for the Joint U.S./Russian Plutonium Disposition Study, Rev. 1, ORNL/MD/LTR-46, Oak Ridge National Laboratory, 1993.

B. B. Bevard, S. R. Greene, et al., U.S. Water Reactors Co-Chair Report for the Joint U.S.  Russian Plutonium Disposition Study, Rev. O., ORNL/MD/LTR-33, Oak Ridge National Laboratory, 1993.

B. B. Bevard and S. R. Greene, U.S. Water Reactors Co-Chair Report for the Joint U.S./Russian Plutonium Disposition Study, Rev. 0, ORNL/MD/LTR-31, Oak Ridge National Laboratory, 1993.

Post # 37: Is Sustainability Enough?

I discussed the most common definition of sustainable energy in Post # 29:

"Sustainable energy is the provision of energy that meets the needs of the present without compromising the ability of future generations to meet their needs."

This definition is fine - as far as it goes.  But I think we need to "double-click" on the word "needs".  Because it's the "quality" of the energy to which we have access that matters.

So, what are the key attributes of a useful energy supply?

1. It must be AFFORDABLE.   Abundance doesn't matter if the commodity isn't affordable.  The technology must exist to harvest the resource with adequate efficiency to deliver a cost-competitive product to market.

2. It must be SECURE - Energy must be available from sources and provided in a manner that does not constrain our foreign policy and our national defense strategies.

3. Energy supply  must be PREDICTABLE.  We need to know WHEN the energy will be available Predictability is based on what I call the "primitive or primary energy source availability".   This is one of the challenges with wind, and solar energy.  Predicting when the wind will blow and the sun will shine with sufficient brightness to be useful for electricity production is difficult in many regions of the world where it is needed.

4. The energy supply must be RELIABLE - Some people combine this with predictable energy, but I distinguish.  To me, reliability is a function of the inherent robustness of the engineered system that collects, converts, stores, and transports the energy from it's point of origin to the end-user.  It is distinct from predictability.

Next, there comes the challenge of distinguishing between our needs and our wants – and even more importantly, between our wants and other peoples needs.  But more about that in a future post...


Just thinking,
Sherrell

Post # 36: More on "Beyond Design Basis" Accidents In Spent Fuel Pools

I provided a short bibliography of documents detailing research that has been done on "beyond design basis" accidents in BWR refueling / spent fuel pools in Post # 33.

Subsequent to that posting I ran across a couple of outstanding documents on the subject that I had overlooked.  They are included in the amended bibliography below as References 3 and 4. 

1. NUREG/CR-0649, "Spent Fuel Heatup Following Loss of Water During Storage,"Allan S. Benjamin, David J. McCloskey, Dana A. Powers, Stephen A. Dupree, March 1979.

2. NUREG/CR-4982, "Severe Accidents in Spent Fuel Pools in Support of Generic Safety Issue 82," V. L. Sailer, K. R. Perkins, J. R. Weeks, H. R. Connell, July 1987.  

3. E. D. Throm, "Regulatory Analysis for the Resolution of Generic Issue 82, Beyond Design Basis Accidents in Spent-Fuel Pools," NUREG-1353, U.S. Nuclear Regulatory Commission, April 1989.

4. Edward D. Throm, "Beyond design basis accidents in spent-fuel pools – Generic Issue 82,", Nuclear Engineering and Design 126 (1991) 333-359.

5. Robvert Alvarez, Jan Beyea, Klaus Janberg, et. al., "Reducing the Hazards from Stored Spent Power-Reactor Fuel in the United States," Science and Gobal Security 11: 1-51, 2003

6. Mihaly Kunstar, Lajos Matus, Nora Ver, et al., "Experimental investigation of the late phase of spent fuel pool accidents," Int. J. Nuclear Energy Science and Technology, Vol. 3, No. 3, 2007, page. 287-301

As one would expect, the NRC as spent a great deal of time on this issue.  The following URL relates to NRC's work on Generic Issue 82, cited in References 3 and 4 above:

http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr0933/sec3/082r3.html

Finally, a quick quote from Reference 4 above, that actually summarizes the conclusions of many that have looked at the issue before:

"Although these studies conclude that most of the spent-fuel pool risk is derived from beyond design basis earthquakes, this risk is not greater than the risk form core damage accidents due to these beyond design basis earthquakes.  Therefore, reducing the risk from spent-fuel pools due of events beyond the safe shutdown earthquake would still leave a comparable risk due to core damage accidents. The risk due to beyond design basis accidents in spent-fuel pools, while not negligible, is sufficiently low that the added cost involved with further risk reduction is not warranted." (italics added by me).

Basically, the conclusions were that any earthquake strong enough to lead to a severe accident in a spent fuel pool would probably also pose a significant threat to the reactor.  Given the low probably of such events, it made little sense to focus on the spent fuel pool when the reactor would normally pose the more significant challenge. These conclusions will almost certainly be revisited in light of recent events at Fukushima.  It will be interesting to track the dialog.


Just thinking...

Post # 35: Fukushima-Like Events In Nuclear Power Plants

Daily we watch the unfolding story at Fukushima and look for signs the progression of the events there have stabilized.  Clearly, recovery, cleanup, and remediation there and throughout the remainder of Japan will continue for a long, long time – even under the best of circumstances, 

This set me to thinking about other Fukushima-like "beyond design basis" event scenarios that could challenge the integrity of our nuclear fleet.  First, I want to define what I mean by "Fukushima-like".

On March 11, Fukushima Dai-Ich Units 1-3 were operating, and the other three units were shutdown for maintenance and refueling.  The "top event" at Fukushima was a Richter 9 earthquake.  The safe shutdown earthquake (SSE) for the Fukushima plant was a Richter 8.2 event.  Thus the Fukushima quake was a "beyond design basis event".  

Within an hour after the quake, a hugh (latest estimate is 14 meters high) tsunami struck the northeastern coast of Japan, visiting death and further devastation on the entire region. I understand from media reports that the Fukushima Dai-Ichi plant was designed for "only" a 6 meter tall tsunami.  Another beyond-design-basis event.  

Fukushima Dai-Ichi was at that moment damaged, and isolated from outside help - on it's own to deal with the impacts of these two "beyond design basis" events.  

It is the combination of the impact of two beyond design basis events, coupled with the utter devastation visited on the entire site and the surrounding region, that defines a "Fukushima-like" event in my mind.  Such an event leaves the reactor damaged, constrained by damage to its sister units on the plant site, and isolated from the surrounding region which is, in any event, unable to render assistance to the plant.   What a nightmare.

Nuclear power plants are remarkably robust facilities, incorporating multiple transmission lines to provide off-site power,  multiple backup station diesel generators in the event all of the transmission lines are severed, and multiple station batteries capable of allowing the plant to remain safely shut down for several hours should the station diesels fail.  But the unique characteristic of nuclear power is that one cannot simply "shut it off".  Decay power levels in nuclear reactors remain at the "few tenths of a percent" level for a few months after the reactor is "scrammed".  Ultimately, long-term accident management depends on the ability of the outside world to provide assistance to recover the decay heat removal function - for both the reactors and any spent fuel stored in fuel pools onsite – before the fuel is significantly damaged.  This didn't happen in Fukushima Dai-Ichi 1-3.

So, forgetting "probabilities of occurrence" for a moment, what are other "Fukushima-like" events?  In addition to earthquakes and tsunamis, I can only think of two events that meet my definition: hurricanes and solar superstorms.  We are all familiar with the impact of hurricanes.  Our coastal nuclear power plants (those subject to hurricanes and tsunamis) typically stage backup equipment many miles inland with arrangements for delivery in the event of a major emergency.  

Fewer people are aware of the potential for natural solar superstorms (such as the 1859 Carrington Event) to wreck havoc on our entire electrical grid - right down to the electrical systems in our cars, cell phones, radios, etc.  According to reliable reports, during the 1859 event, telegraph systems all over North America and Europe failed. Many telegraph operators received harmful shocks.  Telegraph systems burst into flames, and some continued to work when disconnected from their battery-driven power sources (see Wikipedia http://en.wikipedia.org/wiki/Solar_storm_of_1859.  Given the nature of our electric grid and our electrified society, it's hard to comprehend how such an event would impact life as we know it today – with or without nuclear power plants.  Probably deserves some thought...

No nice "wrap-up" on this.  Just thinking...

Post # 34: Natural Gas and Wind Energy Infrastructure Challenges

Yesterday I had the pleasure of speaking at the Infocast's 2011 Small Modular Reactor Seminar (see http://www.infocastinc.com/index.php/conference/smr11) in Washington, D.C.  I spoke about the new Small modular Advanced High Temperature Reactor (SmAHTR) reactor concept my colleagues and I at Oak Ridge National Laboratory have been developing (more about this in a future post).

At any rate, the Infocast seminar featured a number of interesting speakers and panelists.  One of the panelists was David Mohre, Executive Director of the Energy and Power Division of the National Rural Electric Cooperative Association (NRECA) – see http://www.nreca.coop/Pages/default.aspx .  During one of the Q&A sessions, Dave related a rather stunning bit of trivia I thought I would pass along here.

Many folks are touting what I call "silver bullet energy solutions" (or SBES for short) to our nation's energy challenges.  These are single-technology solutions that proponents believe with magically address all our varied energy solution challenges.  Among the most commonly mentioned SBES are natural gas and renewable energy.  Now for the trivia...

First, according to Energy Information Agency, the installed U.S. coal-fired generation capacity in 2009 was 339 GWe (http://www.eia.doe.gov/cneaf/electricity/page/capacity/capacity.html).  Dave indicated analysts have estimated the cost of building the natural gas pipeline infrastructure required to replace 300 GWe of coal-fired electrical generation with gas-turbine generators to $70-80 BILLION.  

Next, he related the estimate for the cost of building the transmission lines required to enable wind turbines to provide 15% of the U.S. electrical generation.  Are you sitting down?  $100 BILLION.

Then he noted that there's less public opposition to underground gas pipelines than to above-ground electrical transmission lines.

I should note that Dave did not cite the specific reference for either of these statements, but I will attempt to uncover it and modify the post when I do.

Just two more challenges to achieving a sustainable energy future....

Just thinking...

Post # 33: Spent Fuel Storage Pool Accidents In Nuclear Power Plants

We all continue to watch the unfolding events at Fukushima and pray for those who are working so hard to terminate the accident progression there, as well as the Japanese people who will be dealing the the aftermath of the historic earthquake and tsunami for a long time.

The events at Fukushima illustrate the fact that Boiling Water Reactor (BWR) nuclear power plants normally have three or four types of used nuclear fuel inventories that must be maintained in a safe state.  These are (1) the reactor core, (2) the spent fuel in the "refueling pool" that sits just beside the reactor, (3) the plant's common spent fuel storage pool, and (4) spent fuel in dry cask storage.

The water level, water chemistry, and water temperature in the refueling and spent fuel pools is carefully monitored and controlled.  The refueling pool is used during plant refueling operations to stage used fuel into and out of the reactor.  Thus fuel in the refueling pool fuel normally has the highest decay heat generation rate of any fuel outside of the reactor.  Separate from the refueling pool is the plant's common spent fuel storage pool, which contains fuel removed from the refueling pools for long-term storage.  The spent fuel pool generally services multiple reactors at multi-reactor sites.  The decay heat level of the fuel in the spent fuel pool is lower than that of the fuel in the refueling pool.  Then finally, there is the spent fuel in dry cask storage that is generally the oldest, coolest spent fuel at the plant.

Any event that threatens the integrity of the refueling pool and spent fuel pool boundaries, leads to leaks, or threatens the pool cooling function, can lead to fuel overheating, hydrogen generation, and fission product release.  Unlike BWR severe accidents, which I spent many years studying, I have not personally analyzed spent fuel pool accidents.  But others have.  So here is a (very) short bibliography of public documents relevant to spent fuel pool accidents – extracted from the cobwebs of my mental attic...

1. NUREG/CR-0649, "Spent Fuel Heatup Following Loss of Water During Storage,"Allan S. Benjamin, David J. McCloskey, Dana A. Powers, Stephen A. Dupree, March 1979.

2. NUREG/CR-4982, "Severe Accidents in Spent Fuel Pools in Support of Generic Safety Issue 82," V. L. Sailer, K. R. Perkins, J. R. Weeks, H. R. Connell, July 1987.  

3. Robvert Alvarez, Jan Beyea, Klaus Janberg, et. al., "Reducing the Hazards from Stored Spent Power-Reactor Fuel in the United States," Science and Gobal Security 11: 1-51, 2003

4. Mihaly Kunstar, Lajos Matus, Nora Ver, et al., "Experimental investigation of the late phase of spent fuel pool accidents," Int. J. Nuclear Energy Science and Technology, Vol. 3, No. 3, 2007, page. 287-301

As one would expect, the NRC as spent a great deal of time on this issue.  The following URL is a good entry point to their analysis:

http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr0933/sec3/082r3.html

Just a quick list of relevant and useful background material from the mental archives of S. R. Greene.

Just thinking...