Diablo Canyon earthquake vulnerability
Encyclopedia
Diablo Canyon 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 fault
s, but was later upgraded to withstand a 7.5 magnitude quake. It has redundant seismic monitoring and a safety system designed to shut it down promptly in the event of significant ground motion.
(DCNPP/DCPP)is located proximal to the Los Osos, Hosgri
, San Andreas and Shoreline fault
s. 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." 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.
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.
In 1985, the USGS of the Department of Interior published a report 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".
More recent studies include probabilitist seismic hazard assessment.
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".
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.In 1994, a probablistic seismic report was released
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.
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.
of the Nuclear Regulatory Commission
provides oversight of Incident response team
s and assures provision of an appropriate Incident commander
for all adverse events including Earthquake
. The company does have in place the following measures:
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. 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. Due to seismic and other concerns, many of these individuals and CBO's demand that DCPP be decommissioned.
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.. 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. 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.
Earthquake
An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. The seismicity, seismism or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time...
from four faults, including the nearby San Andreas
San Andreas Fault
The San Andreas Fault is a continental strike-slip fault that runs a length of roughly through California in the United States. The fault's motion is right-lateral strike-slip...
and Hosgri fault
Hosgri fault
The Hosgri Fault is an offshore fault zone located near the Central Coast of California in San Luis Obispo County. The main fault stretches for about , and the coastal communities closest to it are Cambria, San Simeon and Morro Bay, Baywood Park-Los Osos, and Avila Beach...
s, but was later upgraded to withstand a 7.5 magnitude quake. It has redundant seismic monitoring and a safety system designed to shut it down promptly in the event of significant ground motion.
Introduction
Diablo Canyon Power PlantDiablo Canyon Power Plant
Diablo Canyon Power Plant is an electricity-generating nuclear power plant at Avila Beach in San Luis Obispo County, California. The plant has two Westinghouse-designed 4-loop pressurized-water nuclear reactors operated by Pacific Gas & Electric. The facility is located on about in Avila Beach,...
(DCNPP/DCPP)is located proximal to the Los Osos, Hosgri
Hosgri fault
The Hosgri Fault is an offshore fault zone located near the Central Coast of California in San Luis Obispo County. The main fault stretches for about , and the coastal communities closest to it are Cambria, San Simeon and Morro Bay, Baywood Park-Los Osos, and Avila Beach...
, San Andreas and Shoreline fault
Shoreline Fault
Shoreline Fault is a 25 km long vertical strike-slip fault discovered in 2008 that lies less than a mile from the Diablo Canyon Nuclear Power Plant in California...
s. 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
Sam Blakeslee
Samuel Norman Blakeslee is a Republican California State Senator representing California's 15th State Senate district, a former California State Assemblyman from California's 33rd State Assembly district, and a former State Assembly Republican Leader...
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." 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
California Coastal Commission
The California Coastal Commission is a state agency in the U.S. state of California with quasi-judicial regulatory oversight over land use and public access in the California coastal zone....
, 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
Ed Markey
Edward John "Ed" Markey is the U.S. Representative for , serving since 1976. He is a member of the Democratic Party. The district includes most of Boston's northern and western suburbs, such as Medford and Framingham. Markey is the Dean of both the Massachusetts and New England House delegations...
, the NRC in June 2011 announced that it had already completed its Safety Evaluation Report (SER) for the plant.
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. 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.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.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, CAthe 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.
In 1985, the USGS of the Department of Interior published a report 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".
More recent studies include probabilitist seismic hazard assessment.
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
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".
Shoreline Fault
The Shoreline Fault is a 25 km long vertical strike-slip fault 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. However, mandated three dimensional seismic studies have not been yet completed and will more fully indicate whether the faults are connected or not.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.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.In 1994, a probablistic seismic report was released
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.
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.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.
Preparedness
The Office of Nuclear Reactor RegulationOffice of Nuclear Reactor Regulation
The Office of Nuclear Reactor Regulation is known by the acronym NRR. It is a subordinate part of the United States Nuclear Regulatory Commission.which is itself part of the United States Department of Energy....
of the Nuclear Regulatory Commission
Nuclear Regulatory Commission
The Nuclear Regulatory Commission is an independent agency of the United States government that was established by the Energy Reorganization Act of 1974 from the United States Atomic Energy Commission, and was first opened January 19, 1975...
provides oversight of Incident response team
Incident Response Team
An incident response team or emergency response team is a group of people who prepare for and respond to any emergency incident, such as a natural disaster or an interruption of business operations. Incident response teams are common in corporations as well as in public service organizations...
s and assures provision of an appropriate Incident commander
Incident Commander
The incident commander is the person responsible for all aspects of an emergency response; including quickly developing incident objectives, managing all incident operations, application of resources as well as responsibility for all persons involved. The incident commander sets priorities and...
for all adverse events including Earthquake
Earthquake
An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. The seismicity, seismism or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time...
. 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 diesel w/o power
Design basis
According to information provided by the plant operator Pacific Gas and Electric Stricland 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.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 significant tsunami generation. The plant is located on an eighty five foot coastal bluff and the maximum anticipated tsunami is far less.Soil liquifaction
Soil liquifaction resulting from earthquake activity has been raised as a concern however the plant and storage fuels are anchored on bedrockPost-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.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. 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. Due to seismic and other concerns, many of these individuals and CBO's demand that DCPP be decommissioned.
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.. 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. 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.
See also
- Abalone AllianceAbalone allianceThe Abalone Alliance was a nonviolent civil disobedience group formed to shut down the Pacific Gas and Electric Company's Diablo Canyon Power Plant near San Luis Obispo on the central California coast in the United States...
- Diablo Canyon Power PlantDiablo Canyon Power PlantDiablo Canyon Power Plant is an electricity-generating nuclear power plant at Avila Beach in San Luis Obispo County, California. The plant has two Westinghouse-designed 4-loop pressurized-water nuclear reactors operated by Pacific Gas & Electric. The facility is located on about in Avila Beach,...
- Alliance for Nuclear ResponsibilityAlliance for Nuclear ResponsibilityAlliance for Nuclear Responsibility is a non-profit public interest organization founded in 2005, and based in San Luis Obispo, California. It is focused on public citizen activism and public participation with regard to the Diablo Canyon Power Plant, which some people also call the Diablo Canyon...
- Dark Circle (film)