On Thursday, 2 June 2011, the IAEA provided the following information on the status of nuclear safety in Japan:

Overall, the situation at the Fukushima Daiichi nuclear power plant remains very serious.

The IAEA receives information from various official sources in Japan through the Japanese national competent authority, the Nuclear and Industrial Safety Agency (NISA). This Update Brief is based on information issued by the IAEA Incident and Emergency Centre up to 16:00 UTC on 31 May 2011.

On 13 May TEPCO commenced the preparatory work for the installation of a cover for the reactor building of Unit 1. The reactor building cover will be installed as an emergency measure to prevent the dispersion of radioactive substances until mid- to long term measures, including radiation shielding, are implemented.

TEPCO has reported that information obtained after calibration of the reactor water level gauges of Unit 1 shows that the actual water level in the Unit 1 reactor pressure vessel was lower than was indicated, showing that the fuel was completely uncovered. The results of provisional analysis show that fuel pellets melted and fell to the bottom of reactor pressure vessel at a relatively early stage in the accident.

TEPCO reported that “most part of the fuel is considered to be submerged in the bottom of reactor pressure vessel and some part exposed.” TEPCO also reported that leakage of cooling water from the reactor pressure vessel is likely to have occurred. However, TEPCO considers that the actual damage to the reactor pressure vessel is limited, on the basis of the temperatures now being measured around the reactor pressure vessel.

The results of the analysis are provisional; TEPCO will continue to conduct investigations. Similar analyses will be conducted for Units 2 and 3 when radiation levels allow calibration of the instrumentation.

The daily monitoring of the deposition of caesium and iodine radionuclides for 47 prefectures is continuing. Since 17 May, deposition of I-131 has not been observed. Low levels of Cs-137 deposition were reported in a few prefectures on a few days since 18 May; the reported values range of from 2.2 to 91 Bq/ m2 for Cs-137.

Gamma dose rates values for all 47 prefectures are reported daily by the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan. On 31 May the gamma dose rate reported for Fukushima prefecture was 1.5 µSv/h. In all other prefectures, reported gamma dose rates were below 0.1 µSv/h; with a general decreasing trend. Meanwhile, the decrease of the gamma dose rate has slowed down, since the short-lived radionuclides have decayed away.

Gamma dose rates reported specifically for the monitoring points in the eastern part of Fukushima prefecture, for distances of more than 30 km from the Fukushima Daiichi plant, showed a general decreasing trend, ranging from 0.1 µSv/h to 17 µSv/h, as reported for 31 May.

On-site measurements at the west gate of the Fukushima Daiichi plant indicate the presence of I-131 and Cs-137 in the air in the close vicinity of the plant (within approximately 1 km). The concentrations in air reported for 29 May were about 3 Bq/m3 for I-131 and about 9 Bq/m3 for Cs-137. The values observed in the previous days show daily fluctuations with an overall decreasing tendency.

Tepco sticks to timetable for ‘cold shutdown’, despite revelations plant suffered greater damaged than previously thought

The firm at the centre of Japan’s worst nuclear accident insisted on Tuesday it would bring stricken reactors at the Fukushima Daiichi power plant under control by January 2012, despite evidence that the complex is more seriously damaged than previously thought.

Is nuclear power the answer to the energy crisis? Ian Sample explains how it works – and how we get the awful side-effects of bombs and waste

Nuclear power

The world’s first large-scale nuclear power plant opened at Calder Hall in Cumbria, England, in 1956 and produced electricity for 47 years.

Hamaoka nuclear plant, which sits near a major fault line, to be made more resistant to earthquakes and tsunamis

The operator of Japan’s “most dangerous” nuclear plant has said it will comply with a government request to temporarily close the facility and carry out work to improve its ability to withstand earthquakes and tsunamis.

The threat of a significant impact has been on the minds of astronomers for decades. There have been movies of varying quality made on the subject.

However, the actual danger has been minimal. But now, scientists from NASA are worried that asteroid 1999 RQ36 might be on a collision course with Earth.

1999 RQ36 is the minor planet designation of an Apollo asteroid discovered by LINEAR in 1999. It has a mean diameter of approximately 560 meters, and has been observed extensively with the Arecibo Observatory Planetary Radar and the Goldstone Deep Space Network.

A recent dynamical study by Andrea Milani and collaborators has located a series of eight potential Earth impacts between 2169 and 2199. The cumulative probability of impact is dependent on poorly known physical properties of the object, but is not higher than 0.07% for all eight encounters. While the chances of impact are roughly 1 in 1000, the threat is real enough to make scientists anxious. The technology needed to deflect such an asteroid is in the theoretical phase of its evolution. And while, the collision won’t happen for another 170 years (if it happens at all), the development of such systems has always been all talk and no action.

To accurately assess RQ36′s probability of Earth impact will require a detailed shape model of the asteroid and at least several more years of radar and optical observations to determine the magnitude of the Yarkovsky acceleration.

Separately, RQ36 has been considered multiple times as the target of spacecraft missions, including OSIRIS, due to the low delta-v required to reach it from Earth orbit.

Should 1999 RQ36 reach Earth, the 560 metres wide rock would have devastating effects. Initially, the fallout would impact life for hundreds of miles in every direction. The long term effects are the greater worry however. With dust a debris launched into the atmosphere, light from the Sun would be irreversibly blocked. The results could mean the death of all life on Earth.

Dr. Michio Kaku often talks about these type of Hollywood scenarios. Provided we have enough time, the best course of action would be merely to nudge the asteroid off its trajectory. Accomplish that however you want to accomplish it, perhaps by landing a small device on the surface that has tiny booster rockets on there.

What you don’t want to do is blow it up since that will only put several destructive objects on a collision course with the planet.

Sounds pretty dire doesn’t it? Well, the truth of the matter is that all of that can be avoided with careful planning. But that means starting now and investing money into diversion technologies so that we are not scrambling at the last minute to devise a plan. That way, we are ready when 1999 RQ36 or some other object finds itself on a collision course with the rock we call home.

The 2010 Atlantic hurricane season was forecasted to be a busy one, and so far it has lived up to the expectations. Halfway through the season, the number of tropical storms and hurricanes has almost equaled the average totals for an entire season. Fortunately, we have yet to experience a major disaster comparable to some of the past decades most severe storms, which brought billions of dollars of damage, death and devastation to the regions they bombarded. Here are the eight costliest hurricanes of the 2000s.

1. Katrina $125 billion (2005)

Hurricane Katrina is by far the most devastating natural disaster in modern US history. The storm itself was massive: it was a category 5 with 175 mph winds in the Gulf, though it weakened to a category 3 as it made landfall enough to cause New Orleans levees to fail, flooding up to 80 percent of the city. A great American town was nearly wiped out, and in the process, 1,833 people were killed. People from across the country and world sat in shock as they viewed the now iconic images of people pleading for help from their rooftops and outside of the Superdome. Often overlooked is the fact that the Mississippi Gulf Coast was decimated by the storm surge as well. Katrina caused us to examine every aspect pertaining to how we should deal with hurricanes.

Tropical Storm Karl is bearing down on Mexico, with two dangerous category four hurricanes – Igor and Julia – also sweeping in from the Atlantic. Karl, packing maximum sustained winds of 65mph (100km/h), is close to the Mayan Riviera on Mexico’s Yucatan peninsula. Igor, said to be the season’s most powerful hurricane, is moving west-north-west towards Bermuda. Julia intensified to category four on Wednesday, with winds close to 135mph.

SAN BRUNO, California – Rescue crews and investigators combed through the rubble of a San Francisco suburb on Friday to search for the missing and try to determine how a ruptured fuel line erupted in an intense fireball that killed at least four people on Thursday night, leaving a horrific scene of destruction covering 15 acres.

Smoke hung over the still-smoldering city of San Bruno, and by Friday morning, the blaze was 75 percent contained, Lt. Gov. Abel Maldonado said at a news conference. Four people were confirmed dead, 52 people were injured, and three were critically injured with third degree burns, Mr. Maldonado said. A total of 38 structures had burned, and 7 more were damaged, he added.

“The sun is shining but there is a dark cloud over the city,” San Bruno Mayor Jim Ruane said at that same news conference. “You’ve heard the numbers but the numbers are going to get higher.”

With California Gov. Arnold Schwarzenegger traveling in Asia on business, his lieutenant declared a local state of emergency and expressed his sympathy to the victims.

“We know that a natural gas line ruptured yesterday around 6:24 p.m., but we don’t know what caused it or what happened,” Lieutenant Governor Maldonado said. “We will find out soon.”

Search and rescue crews, including one from the San Mateo coroner’s office, and with assistance from search dogs, picked through the rubble of decimated blocks on Friday and knocked on doors of fire-ravaged homes.

“It looks like a moonscape in some areas,” Millbrae Fire Chief Dennis Haag said. The National Transportation Safety Board, which investigates pipeline accidents, said that it was sending a four-member team to the scene. The blast occurred about 8 miles south of San Francisco, and fire officials said flames reached up to 80 feet in the air.

The boom was so loud and devastating that some officials initially suspected that a plane might have smashed into the neighborhood.

Vijay Duggal was watching football on television when he heard the thundering noise. "I saw a big fireball all around," Mr. Duggal, 60, said in an interview on Friday. “I thought we’d been attacked by a missile. Everything was shaking. I thought, ’this is the end.’"

Mr. Duggal, who has lived in San Bruno for 45 years, grabbed his wife and his mother in law, who was in her nightgown at the time of the explosion, and they ran to the car. His wife did not have time to take her glasses, and they all left without their medications to flee to a friend’s house.

"It was so, so hot," Mr. Duggal said.

Since he left, he has been trying to get information about whether his house still stood, and he doubted whether his two parakeets survived.

“One minute can change your life,” Mr. Duggal said. “Thank God we’re alive.”

As authorities looked into the cause of the blast, residents of the neighborhood said PG&E had already investigated a pungent gas leak over the previous week but did not take action, according to The Bay Citizen.

“They already knew about the leak and they didn’t do anything,” said Alex Monroy, who lives on Claremont Drive, not far from where the broken gas main burst into flames.

San Mateo Assemblyman Jerry Hill said he was "outraged" to learn that some residents had complained to PG&E about gas leaks in the neighborhood "for up to three weeks" before the explosion.

Mr. Hill said the pipe that ruptured was installed in 1948.

"I will be working closely with the Public Utilities Commission to ensure that a thorough investigation is conducted into the cause of this fire," Mr. Hill said in a statement.

Christopher P. Johns, President of Pacific Gas and Electric said at this morning’s news conference that the company had seen the news reports with residents saying they had called complaining of gas odors. The company, Mr. Johns said, was investigating those claims and going back through records to determine when those calls were made and what the company’s response was.

"We have yet to be able to get close enough to the actual source to be able to determine exactly why this happened," Mr. Johns said. “We’re working diligently to do that."

The explosion erupted on a hillside near Interstates 280 and 380, in a residential area about two miles west of San Francisco International Airport. The gas-transmission pipe was 30 inches in diameter and had been buried about 2.5 to 3 feet below the ground, Mr. Johns.Capt. Charlie Barringer of the San Bruno Fire Department said that the whole neighborhood was engulfed in flames by the time firefighters arrived, even though the fire station was only a few blocks from the scene. The water supply in the area was knocked out by the blast, so water to fight the fire had to be pumped from more than two miles away, he said.

The N.T.S.B., records show, previously cited the PG & E Company for shortcomings in its response to a 2008 natural gas leak in Rancho Cordova, one that eventually killed a resident in an explosion. The N.T.S.B. found that the company had used improper piping which allowed gas to leak from a mechanical coupling in 2006. When a neighbor smelled gas, the company delayed nearly 3 hours before sending a properly trained crew to identify the leak, which led to an explosion that same day, according to the N.T.S.B. report.

Don Ford, a photo journalist, said on CBS 5 that the blast left a deep crater dozens of yards wide. "Tomorrow morning, when the sun comes up, it’s going to be something out of Dante," he said.

In surrounding areas on Thursday night, emergency officials went door to door ordering residents from their homes as firefighters struggled to control the flames.

Lieutenant Governor Maldonado said that 67 pieces of fire-fighting equipment — from local and state fire engines to four air tankers — were deployed. San Francisco Fire chief Joanne Hayes-White said her department alone had about 18 engines and trucks at the scene and about 50 firefighters attacking the blaze, according to local news reports.

Their efforts overnight on Thursday were hampered by strong winds, which appeared to be stoking the fire and increasing the risk of its spreading to more houses, Kelly Huston, a spokesman for the California Emergency Management Agency, told CNN.

“We’ve got aircraft and helicopters literally dropping retardant on homes to try to protect them from catching fire,” he said.

For panicked relatives trying to find their loved ones who fled from the conflagration, the night was fraught with anxiety.

Christina Veraflor, 41, who grew up in San Bruno and now lives in the Napa Valley, saw the news about the explosion on television last night. She called her 67-year-old mother, Gilda Tarzia, but she did not answer, and later Ms. Veraflor said it was because she was at the movies.

Ms. Veraflor said she called one of her mother’s friends who works for the San Francisco Fire Department, and that when firefighters went by her mother’s address, they confirmed that the house had burned to the ground.

“I’m waiting patiently to go up there and see if there is anything, even just some burnt photos,” Ms. Veraflor said. “It’s really about the pictures, not about the TVs and the couches and the brand new shutters.”

She added, between tears, that a friend’s mother is missing and that she has three friends in the hospital in critical condition.

When Ms. Veraflor was visiting her mom about six weeks ago she said she smelled gas but she did not call PG&E. “That happened a lot in that area,” she said. “You would get a whiff of gas and then it would disappear,” she said.

ROSTOV-ON-DON, Russia – A suicide car bomber hit the central market of a major city in Russia’s North Caucasus on Thursday, killing at least 15 and wounding more than 100 people in one of the worst terror attacks in the volatile region in years, officials said.

The attacker detonated his explosives as he drove by the main entrance to the Vladikavkaz market, according to the Emergency Situations Ministry.

At least 15 people, including the suicide bomber, were killed and 133 were wounded in the explosion, said Alexander Pogorely of the Emergency Situations Ministry’s branch in southern Russia. He said 87 of the injured were hospitalized, many in grave condition.

Russian television stations showed a shrapnel-littered square in front of the market, with blood stains on the pavement and rows of vehicles scarred by the blast.

Russian President Dmitry Medvedev sent his regional envoy to Vladikavkaz to help coordinate efforts to help the victims.

No one has immediately claimed responsibility for the bombing, which was the deadliest such attack in the region since a double suicide bombing killed 12, mostly police officers, in the province of Dagestan in April. Twin suicide bombings on Moscow subway in March killed 40 people and wounded over 100.

The market and its surrounding blocks has been the target of several bomb attacks over the past dozen years, in which scores of people have died.

Vladikavkaz is the capital of the Russian republic of North Ossetia. Although it is less plagued by violence than some other republics in the region such as Chechnya and Dagestan, North Ossetia has suffered ethnic tensions and frequent terror attacks.

It was the scene of the 2004 Beslan crisis, in which Chechen terrorists took hundreds of hostages at a school — a siege that ended in a bloodbath killing more than 330 people, about half of them children.

The Vladikavkaz market was bombed in 1999, killing 55. Another bombing in 2001 killed six people. In 2004, 11 people died when a minibus stopped near the market was bombed.

Russia‘s North Caucasus region has been gripped by violence stemming from two separatist wars in Chechnya and fueled by endemic poverty, rampant official corruption and police abuses.

In the Caspian Sea province of Dagestan, officials said Thursday that a hotel employee and another civilian were shot to death by men trying to build a bomb in their hotel room.

Republican Interior Ministry spokesman Vyacheslav Gasanov said the shooting took place late Wednesday in the capital Makhachkala. He said three armed men fled a room in the small hotel after an explosion and opened fire on a hotel clerk and another person who confronted them. He says police found several bombs and six grenades in the room.

In the Dagestani town of Khasavyurt, on the border with Chechnya, a policeman returning home from work was shot to death, Gasanov said.

NUEVO LAREDO, Mexico – Mexican authorities opened shelters and warned people to watch out for mudslides Monday as Tropical Storm Hermine approached the northeastern border with Texas, the second major storm to hit the area this season.

Hermine could approach hurricane strength before making landfall early Tuesday in a sparsely populated area about 50 miles (80 kilometers) south of Matamoros, a city bordering Brownsville, Texas, according to the National Hurricane Center in Miami.

A hurricane watch was issued for the area from Rio San Fernando, Mexico, northward to Baffin Bay in Texas.