Diablo Canyon earthquake vulnerability

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Diablo Canyon (Nuclear) Power Plant, located on the water's edge in San Luis Obispo County California, was originally designed to withstand a 6.75 magnitude earthquake from four faults, including the nearby San Andreas and Hosgri faults,[1] but was later upgraded to withstand a 7.5 magnitude quake.[2] It has redundant seismic monitoring and a safety system designed to shut it down promptly in the event of significant ground motion.

Global earthquake epicenters, 1963–1998

Contents

[edit] Introduction

Diablo Canyon Power Plant (DCNPP/DCPP)is located proximal to the Los Osos, Hosgri, San Andreas and Shoreline faults. Many of these were discovered late in the process of design and construction, necessitating redesign. Construction errors compounded the delays and expense before the plant went online and began producing. Thereafter, discovery of the Shoreline fault caused a round of controversy leading Assemblyman Sam Blakeslee to introduce legislation mandating 3-D seismic studies. The Shoreline Fault is described in the November 2008 PG*E report as an "alignment of microseismicity subparallel to the coastline indicating the possible presence of a previously unidentified fault located about 1 km offshore of DCPP."[3] The plant is up for relicensing and, in the Fukushima aftermath, there is renewed opposition due in part to public perception that the risk of earthquake or tsunami make the plant unsafe. On the other hand, company officials contend that the plant is inherently safe from tsunami due its situation on an 85 foot coastal bluff. Re-licensing is contingent upon consistency with the Coastal Act and thus review by the California Coastal Commission, however seismic issues are more properly within the purview of the Nuclear Regulatory Commission. Much to the chagrin of some parties, such as U.S. Representative Ed Markey, the NRC in June 2011 announced that it had already completed its Safety Evaluation Report (SER) for the plant. [4][5]

[edit] Public controversy

Critics contend that the Diablo Canyon (Nuclear) Power Plant was built so close to a set of geological fault lines that it is for all practical purposes to be regarded as built "directly over" an earthquake fault. [6][7]This is the Hosgri fault which was discovered while the plant was under construction, and led to massive redesign. More recently, the Shoreline fault was discovered, a few hundred meters offshore, sparking renewed interest in the controversy.Template:Citation needed

[edit] Earthquake overview

An earthquake (also known as a quake, tremor or temblor) is the result of a sudden release of energy in the Earth's crust that creates seismic waves. The seismicity or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time. The largest earthquakes in historic times have been of magnitude slightly over 9, although there is no limit to the possible magnitude. The most recent large earthquake of magnitude 9.0 or larger was a 9.0 magnitude earthquake in Japan in 2011 (as of March 2011), and it was the largest Japanese earthquake since records began. At the Earth's surface, earthquakes manifest themselves by shaking and sometimes displacement of the ground. When the epicenter of a large earthquake is located offshore, the seabed may be displaced sufficiently to cause a tsunami. Earthquakes can also trigger landslides, and occasionally volcanic activity.

[edit] Early geologist perspectives

From a more scientific perspective, the geology is as follows:" Three Pliocene-Miocene marine sedimentary units dominate the geology of Diablo Canyon: the Pismo Formation, the Monterey Formation, and the Obispo Formation. According to a Lawrence-Berkely report entitled Geologic Investigation of a Potential Site for a Next-Generation Reactor Neutrino Oscillation Experiment – Diablo Canyon, San Luis Obispo County, CA [8]the area is tectonically active, located east of the active Hosgri Fault and in the southern limb of the northwest trending Pismo Syncline." The Obispo Formation is made up of marine and volcaniclastic sedimentary rocks. [9] [10][11][12][13][14] In 1985, the USGS of the Department of Interior published a report[15] by Kenneth Campbell, at that point in the history of earthquake science probably a "deterministic study", entitled "Empirical prediction of near-source ground motion for the Diablo Canyon power plant site, San Luis Obispo County, California".[16] More recent studies include probabilitist [17]seismic hazard assessment. [18]

[edit] Seismic source characterization studies

Various techniques are used to identify faults. These include:

  • aeromagnetic survey
  • marine magnetic survey
  • seismic reflection profiling
  • seismicity
  • sub-bottom profiling
  • geologic mapping
  • geodetic survey
  • gravity survey

[19]

As a result of studies by PG&E, it is determined that "ground motions from strike-slip earthquakes along the Hosgri fault zone have decreased and the ground motions from the reverse-slip earthquakes on the Los Osos and San Luis Bay fault zones have remained about the same". [20][21]

[edit] Shoreline Fault

The Shoreline Fault is a 25 km long vertical strike-slip fault[22] discovered in 2008 that lies approximately three hundred meters from the Diablo Canyon Nuclear Power Plant in California. According to Pacific Gas and Electric, the fault may produce quakes up to 6.5 magnitude. Pacific Gas and Electric asserts that the facility is able to withstand a 7.5 magnitude quake.[23] However, mandated three dimensional seismic studies have not been yet completed and will more fully indicate whether the faults are connected or not. Template:Citation needed

[edit] Safety

[edit] Fuel rod assembly vulnerability

In response to concern that ground acceleration, or shaking, could cause spillage of submerged fuel rod assemblies which, upon exposure to air, could ignite, PG&E and NRC regulators insist that the foregoing scenario is anticipated and controlled for, and that there is no basis to anticipate spillage. [24] Additional seismic studies are in process, however completion of those studies is not a condition precedent to reissuance of the operating licenses for the two onsite units.[25]In 1994, a probablistic seismic report was released [26][27] Additional seismic studies are in process, however completion of those studies is not a condition precedent to re-issuance of the operating licenses for the two onsite units. [28]


[edit] Risk estimates

The Nuclear Regulatory Commission's estimate of the risk each year of an earthquake intense enough to cause core damage to the reactor at Diablo Canyon was 1 in 23,810, according to an NRC study published in August 2010.[29][30] At a community forum in San Luis Obispo, NRC, PG&E and academic experts presented information on seismic risks to the general public. This included a review of both older deterministic and more contemporary probablistic studies. [31]

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[edit] Preparedness

The Office of Nuclear Reactor Regulation of the Nuclear Regulatory Commission provides oversight of Incident response teams and assures provision of an appropriate Incident commander for all adverse events including Earthquake. The company does have in place the following measures:

  • Severe Accident Management Guidelines (SAMG)
    • Controlling reactor coolant pressure and temp, containment pressure and H concentration
    • Flood containment
    • emergency steam injection into generators
  • Extreme Damage Mitigation Guidelines
    • Spent fuel pool water replacement measures
    • Depressurizaiton of steam generators
    • reduction of pressure w/o power
    • start deisel w/o power


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[edit] Design basis

According to information provided by the plant operator Pacific Gas and Electric [32][33] the plant is designed to accommodate a ground acceleration of 0.75 g - three quarters of gravity. By comparison, the ground tremors experienced by the Fukushima Daiichi power plant was reported as 0.2-0.51 g. The design basis of Fukushima Daiichi is licensed as 0.18-0.36.

[edit] Tsunami

Tsunami may result from earthquakes particularly those originating in offshore submarine landslides and tremors, but PG&E sources emphasize that the geologic conditions proximal to DCPP are not conducive to signifigant tsunami generation.Template:Citation needed The plant is located on an eighty five foot coastal bluff[34] and the maximum anticipated tsunami is far less.Template:Citation needed

[edit] Soil liquifaction

Soil liquifaction resulting from earthquake activity has been raised as a concern [35] however the plant and storage fuels are anchored on bedrock [36]

[edit] Post-Fukushima developments

In April 2011, in the wake of the Fukushima nuclear incident in Japan, PG&E asked the NRC not to issue license renewals until PG&E can complete new seismic studies, which are expected to take at least three years.[37][38] The ongoing (as of 6/2011) seismic studies were recommended by the California Energy Commission and are approved and funded by the California Public Utilities Commission. [39] Community based organizations and activists contend that the plant is inherently unsafe due to the earthquake faults, the lack of knowledge about them, and a putatively inadequate track record of government and private industry in the anticipation and control of such hazards. [40] [41][42] Due to seismic and other concerns, many of these individuals and CBO's demand that DCPP be decommissioned. [43]


The seismic studies imposed by government add to the cost and perhaps eventually the delays experienced by the plant operator. The nuclear industry inherently requires long range planning for capital formation, licensing and waste disposal and these factors have been identified as problematicizing the industry, leading to its collapse.. [44] In Collapse of an Industry,: Nuclear Power and the Contradictions of U.S.Policy, John L. Campbell contrasts how regulatory mechanisms in the US and Germany differ from France, which tends to exclude citizen participation in public policy. Sweden, according to Campbell, occupies something of a middle ground, with extensive citizen input in the policy formation phase, unlike the US and Germany wherein citizen input tends to be at the implementation level, or France, where there is virtually no citizen participation. [45] given the heightened awareness of the dangers of nuclear power plants situated on the coast and close to earthquake faults, many observers have speculated that the declining public confidence in nuclear energy may lead to emulation of German scepticism of nuclear power plants. [46]

[edit] References

  1. "Energy: A Nuclear Horror". Time. February 9, 1976. http://www.time.com/time/magazine/article/0,9171,917988,00.html. Retrieved July 14, 2010.
  2. David Sneed (August 9, 2011). "Diablo Canyon workshop to focus on earthquakes". The San Luis Obispo Tribune. http://www.sanluisobispo.com/2010/08/08/1244213/diablo-canyon-workshop-september.html.
  3. http://www.pge.com/includes/docs/pdfs/shared/edusafety/systemworks/dcpp/2_SFZ_EXECUTIVE_SUMMARY.pdf
  4. http://pbadupws.nrc.gov/docs/ML1115/ML11153A103.pdf
  5. a4nr.org
  6. Protest Diablo: Living and Dying Under the Shadow of a Nuclear Power Plant - Living and Dying Under the Shadow of a Nuclear Power Plant|By: Paul Wolff , Dianne Conn , Judith Evered|Paperback|Createspace (12/05/2010)|ISBN: 1453636196|
  7. http://www.mothersforpeace.org
  8. Geologic Investigation of a Potential Site for a Next-Generation Reactor Neutrino Oscillation Experiment – Diablo Canyon, San Luis Obispo County, CA|Celia Tiemi Onishi, Patrick Dobson, and Seiji Nakagawa|Earth Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA|Steven Glaser and Dom Galic|Department of Civil and Environmental Engineering, University of California, Berkeley, CA 94720 USA
  9. http://www.ce.berkeley.edu/~glaser/documents/theta13_tunnel_finalreport.pdf
  10. "The Diablo Canyon Nuclear Power Plant, a 48-Year Odyssey". KCET. March 25, 2011. http://www.kcet.org/updaily/socal_focus/environment/31573-diablo-canyon-nuclear-power-plant.html. Retrieved May 20, 2011.
  11. "Is Diablo Canyon prepared for possible earthquake?". KSBY.com. March 14 2011. http://www.ksby.com/news/is-diablo-canyon-prepared-for-possible-earthquake-/. Retrieved May 20, 2011.
  12. http://www.fox40.com/news/headlines/ktxl-californias-two-nuclear-plants-near-fault-lines-20110314,0,3265997.story
  13. http://www.newsmax.com/InsideCover/Newsom-California-Diablo-canyon/2011/03/17/id/389759
  14. http://www.capradio.org/articles/2011/03/25/is-california-underestimating-quake-threat-to-nuclear-plants
  15. Campbell, Kenneth W; Geological Survey (U.S.) (1989) (in English), Empirical prediction of near-source ground motion for the Diablo Canyon power plant site, San Luis Obispo County, California [microform] / Kenneth W. Campbell, Dept. of the Interior, U.S. Geological Survey : [Books and Open-File Reports Section, distributor]
  16. Kenneth W Campbell (1989). "Empirical prediction of near-source ground motion for the Diablo Canyon power plant site, San Luis Obispo County, California". Denver, Colo: Dept. of the Interior, U.S. Geological Survey. http://openlibrary.org/books/OL13612932M/Empirical_prediction_of_near-source_ground_motion_for_the_Diablo_Canyon_power_plant_site_San_Luis_Obispo_County_California.
  17. http://www.nrc.gov/reading-rm/doc-collections/fact-sheets/probabilistic-risk-asses.html
  18. Seismic Information Workshop|September 8-9, 2010|San Luis Obispo, CA|Agenda of Nuclear Regulatory Commission
  19. Seismic Information Workshop|September 8-9, 2010|San Luis Obispo, CA|Agenda of Nuclear Regulatory Commission
  20. http://www.pge.com/includes/docs/pdfs/shared/edusafety/systemworks/dcpp/3_SFZ_Section_1_Introduction.pdf
  21. http://www.pge.com/includes/docs/pdfs/shared/edusafety/systemworks/dcpp/2_SFZ_EXECUTIVE_SUMMARY.pdf
  22. http://www.sciencedaily.com/releases/2010/06/100602215239.htm ScienceDaily:Revised Seismotectonic Model for California Central Coast: More Complex Than Previously Thought]
  23. http://www.santamariatimes.com/news/local/govt-and-politics/article_8c1f14cc-2c11-11df-b385-001cc4c03286.html Santa Maria Times:Supervisors request delay for Diablo relicensing
  24. "Diablo Canyon Independent Safety Committee’s Evaluation of Pressurized Thermal Shock and Seismic Interactions for a 20-Year License Extension at the Diablo Canyon Nuclear Power Plant". Diablo Canyon Independent Safety Committee. 2011. http://www.dcisc.org/pts-public-release.php. Retrieved March 18, 2011.
  25. "In The World of Nuclear Power Crisis". Life Magazine: pp. 23–30. May 1979. http://www.mindfully.org/Nucs/TMI-LifeMay79.htm. Retrieved July 14, 2010.
  26. Bozoki, G. E; U.S. Nuclear Regulatory Commission. Division of Safety Issue Resolution; Brookhaven National Laboratory (1994) (in English), Review of Diablo Canyon Probabilistic Risk Assessment [microform] / prepared by G.E. Bozoki ... [et al.], Division of Safety Issue Resolution, Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission : Supt. of Docs., U.S. G.P.O. [distributor]
  27. "Diablo Canyon Independent Safety Committee’s Evaluation of Pressurized Thermal Shock and Seismic Interactions for a 20-Year License Extension at the Diablo Canyon Nuclear Power Plant". Diablo Canyon Independent Safety Committee. 2011. http://www.dcisc.org/pts-public-release.php. Retrieved March 18, 2011.
  28. "In The World of Nuclear Power Crisis". Life Magazine: pp. 23–30. May 1979. http://www.mindfully.org/Nucs/TMI-LifeMay79.htm. Retrieved July 14, 2010.
  29. Dedman, Bill (March 17, 2011). "What are the odds? US nuke plants ranked by quake risk". msnbc.com. http://www.msnbc.msn.com/id/42103936/. Retrieved April 19, 2011.
  30. http://msnbcmedia.msn.com/i/msnbc/Sections/NEWS/quake%20nrc%20risk%20estimates.pdf
  31. Seismic Information Workshop|September 8-9, 2010|San Luis Obispo, CA|Agenda of Nuclear Regulatory Commission
  32. Stricland
  33. DCPP Facility Review|Jearl Strickland|Presentation to Santa Barbara Board of Supervisors|May 10,2011
  34. Strickland
  35. NRC-PG&E public forum|September 2011|San Luis Obispo, CA
  36. Strickland
  37. Upton, John (March 17, 2011). "Seismic Uncertainty at Diablo Canyon". The Bay Citizen. http://www.baycitizen.org/pge/story/diablo-canyon/. Retrieved 2011-04-19.
  38. Casselman, Ben; Stephen Power (April 12, 2011). "Diablo Plant Delays License Bid for Quake Study". The Wall Street Journal. http://online.wsj.com/article/SB10001424052748704529204576257302591577840.html. Retrieved 2011-04-19.
  39. PG&E Letter DCL-11-047|April 10, 2011|To NRC
  40. Letter of Judith Evered, Women's International League for Peace and Freedom| To Nuclear Regulatory Commission|Entered public record agenda item # 3 Late distribution County of Santa Barbara| June 16, 2011
  41. http://www.mothersforpeace.org
  42. a4nr.org
  43. http://www.independent.com/news/2011/jun/22/legalize-clotheslines/%7CLetter of Brian Rosen
  44. Author(s): John A. Hall| American Journal of Sociology, Vol. 94, No. 6 (May, 1989), pp. 1449-1451|Publisher The University of Chicago Press|Stable URL: http://www.jstor.org/stable/2780975
  45. Collapse of an Industry: Nuclear Power and the Contradictions of U.S. Policy (Cornell Studies in Political Economy) John L. Campbell
  46. seven German reactors that went into operation before 1980 will be offline for three months while Germany reconsiders its plans to extend the life of its atomic power plants. One of them, the Neckarwestheim I reactor, a 35-year-old plant, will remain shut down permanently.|Letter of Liz Apfelberg|"Deny Diablo license|http://www.independent.com/news/2011/mar/22/deny-diablo-license/

[edit] External links