* The most powerful recorded earthquake occurred at Lebu, Chile, on May 22, 1960. It measured an intensity of 9.5 on the Richter scale. The energy released by the Hiroshima atomic bomb in August 1945 was the equivalent of 5.7 on the Richter scale. [Ref: Agence France Presse, "The Richter scale: when 6 or 7 means life or death", May 27, 2003]

July 25, 2007

NEW SESMIC FAULTS REGULARLY DISCOVERED

Bangkok Post. "N-option needs careful thought", lead editorial, July 25, 2007, p. 10

The whole of Japan, of course, is ... an ... earthquake-prone ... area. There are 55 reactors in Japan, and almost all of them are on or near major fault lines. Some, but obviously not all, are built to withstand an 8.5 earthquake, which is considered the maximum magnitude which might be encountered. There are, of course, rare earthquakes on record which have been more powerful.

In the US, there are nuclear power plants in California located on or near known faults, and also in the mid-West region. It has been pointed out that the proposed repository for nuclear waste material at Yucca Mountain in Nevada lies on a fault line. The nuclear reactor being constructed near the Iranian city of Bushehr is near an active fault.

Probably no one knows for sure how many existing nuclear plants are on or nearby known fault lines. What's more, new fault lines are being discovered all the time. In fact, an analysis of the seismic data from the July 16 quake shows that the Kashiwazaki-Kariwa plant, previously thought to be near a fault, is apparently directly on top of an extension of the fault.

December 20, 2006

* Overly conservative NRC regulation: Seismic calculations for piping system design

* [2006-03-31] Predicting earthquakes from space
RIA Novosti

April 16, 2005

* Bechtel to cut 700 more jobs; layoffs at vit plant hit 1,000 in past month
Annette Cary, Hanford News (subscription)

To meet legal deadlines and to get waste out of underground tanks sooner, construction on the Hanford vitrification plant started as design work continued. Building is about 35 percent complete, and the design is about 70 percent complete. Work has substantially slowed at the two massive buildings at the plant that will handle highly radioactive waste -- the Pretreatment Facility and the High-Level Waste Vitrification Facility. In December, results of a new study indicated that design standards at the two buildings handling high-level radioactive waste might not be adequate to withstand a worst-case earthquake. The design standard must be increased 38 percent for earthquake safety at the buildings that will handle high-level radioactive waste. Engineers have started reviewing and validating the thousands of calculations already completed on the design. Bechtel had expected to lay off about 800 engineers steadily through 2005 as a substantial portion of the design work was completed. Instead, many of those engineers will keep their jobs to work on the more robust design calculations. The design changes are expected to be greatest at the upper levels of the buildings, which would move more in an earthquake, limiting the improvements that may be needed on construction already completed. The walls are about half way up on the largest building, the Pretreatment Facility, where waste will be separated into high-level and low-activity waste streams for treatment. The building will have a footprint the size of four football fields and stand about 120 feet high.

DOE also has decided that the design work needs to be completed further ahead of construction as the plant has faced other challenges. Getting materials and equipment produced to nuclear-grade standards has been a challenge since manufacturing experience has diminished after the United States stopped building new nuclear plants. The slowdown in construction will allow more time for the purchase and delivery of commodities, such as piping and pipe hangers.

Work will continue on schedule on the third large building at the plant, the Low-Activity Waste Vitrification Facility, and at the Analytical Laboratory and scores of support facilities. The cost of the plant will be more than the $5.8 billion planned for construction and testing now, DOE has warned.

September 18, 2004

China - Yangjiang site earthquake points to slim-looking design safety margin

Provincial government officials recently approved plans to begin building the mainland's biggest nuclear plant in Yangjiang by the end of next year. Yesterday, at about 2.33am, the city was struck by a 4.9-magnitude quake. Yang Maling, director of Guangdong's Earthquake Prediction and Research Centre, said its experts had carefully studied the safety aspects of the planned 66 billion yuan nuclear plant: "We have studied the possibility and strength of tremors Yangjiang will face. We have analysed the risk of building a nuclear plant there and will be constructing a plant that can withstand earthquakes measuring seven in seismic intensity." Mr Yang said yesterday's quake was the third-strongest Yangjiang had experienced since 1969, when it was jolted by a 6.9-magnitude tremor.

[Source: Peter Michael and Kristine Kwok (South China Morning Post), "Quake jolts site of new nuclear power plant; Tremors felt 240km away in Hong Kong, but expert says it is still safe to build", South China Morning Post, September 18, 2004, p. 3]

July 29, 2004

* Callaway withdraws request to apply American Society of Civil Engineers (ASCE) 4-86 "100-40-40" load combination methodology for combining components of seismic response loads

December 26, 2003

Russian high-seismic reactor design uses 9.0 as basis

"For seismically dangerous regions, Russian organizations design nuclear power plants that could withstand seismic shocks of up to nine points. The power generation unit at the Bushehr nuclear power plant was also designed [on that basis] and even with some extra margin".

[Source: Konstantin Kuranov (the first deputy president of Atomstroyeksport), quoted by ITAR-TASS news agency, Moscow, "Russians say Bushehr nuclear power plant in Iran unaffected by quake", December 26, 2003 1043 gmt (translated from the ussian by BBC Monitoring)]

December 25, 2003

Diablo Canyon felt Monday's quake, but it wasn't strong enough to trigger shutdown

After Monday's San Simeon earthquake, Diablo Canyon conducted the procedurally-required follow-up inspections -- tasks which took several workers several hours to complete. Senator Barbara Boxer has asked the NRC to conduct an additional emergency inspection at the plant. Boxer said she has been advised that a quake could damage the underlying foundation of the plant's reactors. "I request you inspect the foundation as well as the cooling tubes and other piping in the facility," she said. "It's important to rule out any damage and therefore any increased risk that may have been caused by the earthquake," she said.

[Ref: Carol Roberts (Knight Ridder Newspapers), "Boxer seeks thorough inspection of nuclear plant", Contra Costa Times, December 25, 2003]

* Diablo Canyon - NRC's reply to Sen. Boxer's post-earthquake request

The fault involved in Monday's San Simeon earthquake (magnitude 6.5) is the same type which prompted precautionary decommissioning of GE's test reactor at Vallecitos

The Verona fault is a "thrust fault" in California. Although the Geological Survey's scientists can't estimate how large a quake it might produce if it ever ruptures, the unpredictable possibility of a strong temblor on that fault caused the government to order General Electric to dismantle its old nuclear reactor near Pleasanton in 1977. The fault runs almost directly beneath the GE site, where nuclear fuel research is still conducted. In thrust faults, one block of the Earth's crust moves up or down relative to the fault's other side. This is very different than what happens with faults like the world-famed San Andreas, where the two sides of the fault move past each other side by side -- a motion scientists call "strike-slip."

[Ref: David Perlman (Chronicle Science Editor), "Bay Area home to thrust faults; Some are hidden from scientists' view", San Francisco Chronicle, December 25, 2003, p. A-8]

December 10, 2003

* North Anna - 4.5 earthquake centered 29 miles from plant

July 1, 2003

* Perry - Unusual Event prompted by Ohio earthquake (3.4 on Richter scale)

May 26, 2003

N-plant apparently fine near epicenter of today's 7.0 earthquake in Japan

Here's some excerpts from a variety of press reports out of Japan today

Reuters, "Japan Stocks Seen Up After Bank Earnings", May 26, 2003 7:36:00 PM ET

Tohoku Electric Power Co [,] ... [t]he medium-sized power supplier to the Tohoku and Niigata areas said on Monday that an 825,000 kilowatt (kW) nuclear reactor, the Onagawa No.3 unit in northern Japan, automatically shut itself due to an earthquake that hit the area. Tohoku's two other nuclear reactors at the same plant were already shut due to regular maintenance checks, a spokesman said. The nuclear power plant is located in Miyagi prefecture, which was hit by a strong earthquake on Monday afternoon.

---

Deutsche Welle, "Quake rocks northern Japan", May 26, 2003 23:00 UTC Ê

Japan's strongest earthquake in three years - across its northeastern regions - has left nearly 100 people injured. No deaths have been reported. The 'quake measured 7.0 on the Richter scale, buckling roads, and automatically shutting down one nuclear reactor at Onagawa and Bullet train services. Its epicentre was deep off Japan's eastern coast. Authorities say a Tsunami was not likely.

---

Colin Joyce (The London Telegraph's Tokyo correspondent), "Panic in Japan as powerful quake strikes", May 27, 2003

The wisdom of building nuclear power stations in a country prone to major quakes has been questioned but, yesterday, the Onogawa nuclear plant in Miyagi shut down automatically with no apparent problems.

... A powerful earthquake rocked northern Japan yesterday, causing widespread panic, stopping train services, closing roads and shaking buildings as far away as Tokyo, 280 miles to the south. It measured 7.0 on the Richter scale at its epicentre off the Miyagi coast... [and] occurred at a depth of 40 miles, which means shaking is less violent... [T]here were no reports of deaths or serious damage to buildings. Miyagi and Iwate prefectures, which were hardest hit, are largely rural. In Sendai, a city with a population of a million, the ground shook for almost two minutes, which is unusually long, causing shoppers to run into the streets in panic. Cabinets toppled over in offices and goods were thrown from supermarket shelves. Residents said the quake started as a mild shaking before suddenly reaching a strength at which it became difficult to stand. Small fires broke out in residential areas, though it was not clear if they were a direct result of the quake. Mountain roads were strewn with rocks from landslides and other roads were cracked. ... In Tokyo, tall buildings swayed from the shockwaves. Japan is notoriously quake prone, sitting above several active fault lines. Experts believe a major quake in Tokyo is inevitable in the long term. The capital was last devastated in 1923.

---

Howard W. French (New York Times' Tokyo correspondent), , "Strong Quake in Northern Japan Leaves Damage and 78 Injuries", May 26, 2003

A powerful earthquake struck northern Japan today, injuring at least 78 people, starting fires and damaging buildings throughout the region. The earthquake, reported to have a magnitude of 7.0, caused no fatalities, but frightened many, and disrupted services in a broad swath of northern Japan. The Tohoku Electric Power Company said an 825,000-kilowatt nuclear reactor, its Onagawa No. 3 unit, which is situated near the epicenter in northern Japan, automatically shut down. Of those hurt, 49 were injured in landslides. The temblor, which was the strongest earthquake to hit Japan in two years, was powerful enough to be strongly felt 280 miles away, in Tokyo, where tall buildings were shaken for several minutes, street lamps swayed and elevators in some buildings ceased operating when the seismic activity began, at 6:24 p.m.

... Experts said the earthquake's power was muted by the location of its epicenter, which was not only 20 miles offshore Miyagi prefecture, on the northeastern Pacific coast, but 40 miles beneath the earth's surface. The depth of the seismic activity also eliminated the risk of tsunamis, or huge sea waves.

---

Agence France-Presse (Tokyo correspondents), "Earthquake rocks northern Japan", May 27, 2003

The quake, measuring 7.0 on the Richter scale, was the strongest to hit Japan and its surrounding area since last March, when a 7.2 tremor struck the sea between Taiwan and the southern tip of the Okinawa chain.

A nuclear reactor in the Pacific seaside town of Onagawa, near the epicentre, was automatically shut down but there were no reports of damage. Other reactors were operating normally, the National Police Agency said.

Another tremor, registering 4.9 on the Richter scale, rocked the same region four hours later but there were no immediate reports of injuries or property damage.

---

Yomiuri Shimbun, "Strong earthquake rattles Tohoku region", May 27, 2003

At around 6:24 p.m., the quake rocked the region, recording a magnitude of 7 on the open-ended Richter scale with its center located in waters 20 kilometers southeast off Kesennuma, Miyagi Prefecture, and 71 kilometers below the seabed, according to the agency.

The quake measured an intensity of upper 5 in inland Iwate Prefecture, as well as Aomori Prefecture's eastern region and Yamagata Prefecture's Murayama region, lower 5 in Iwate Prefecture's northern coastal region and southern Miyagi Prefecture, Fukushima Prefecture's coastal and inland areas, and Yamagata Prefecture's Mogami region.

The quake was felt from Hokkaido down to the Kinki region, and measured an intensity of 3 in central Tokyo, Yokohama and Saitama.