Water-Powered Spaceship Could Make Mars Trip on the Cheap

Spaceships powered primarily by water could open up the solar system to exploration, making flights to Mars and other far-flung locales far cheaper, a recent study has found.

A journey to Mars and back in a water-fueled vehicle could cost as little as one space shuttle launch costs today, researchers said. And the idea is to keep these “space coaches” in orbit between trips, so their relative value would grow over time, as the vehicles reduce the need for expensive one-off missions that launch from Earth.

The water-powered space coach is just a concept at the moment, but it could become a reality soon enough, researchers said. [Video: Space Engines: The New Generation]

“It’s really a systems integration challenge,” said study lead author Brian McConnell, a software engineer and technology entrepreneur. “The fundamental technology is already there.”

Space coach: The basics

The space coach concept vehicle is water-driven and water-centric, starting with its solar-powered electrothermal engines. These engines would super-heat water, and the resulting steam would then be vented out of a nozzle, producing the necessary amount of thrust.

Electrothermal engines are very efficient, and they’re well-suited for sustained, low-thrust travel, researchers said. This mode of propulsion would do the lion’s share of the work, pushing the space coach from Earth orbit to Mars.

Smaller chemical rockets could be called into service from time to time when a rapid change in velocity is needed, McConnell said.

The space coach’s living quarters would be composed of a series of interconnected habitat modules. These would be expandable and made of fabric, researchers said — much like Bigelow Aerospace’s inflatable modules, which have already been deployed and tested in low-Earth orbit.

Water would be a big part of the space coach’s body, too, according to the study. Packed along the habitat modules, it would provide good radiation shielding. It could also be incorporated into the fabric walls themselves, freezing into a strong, rigid debris shield when the structure is exposed to the extreme cold of space.

Rotating the craft could also generate artificial gravity approximating that of Earth in certain parts of the ship, researchers said.

Slashing the cost of space travel

The dependence on water as the chief propellant would make the space coach a relatively cheap vehicle to operate, researchers said. That’s partly because electrothermal engines are so efficient, and partly because the use of water as fuel makes most of the ship consumable, or recyclable.

Because there are fewer single-use materials, there’s much less dead weight. Water first used for radiation shielding, for example, could later be shunted off to the engines. Combined, these factors would translate into huge savings over a more “traditional” spacecraft mission to Mars using chemical rockets, according to the study.

“Altogether, this reduces costs by a factor of 30 times or better,” McConnell told SPACE.com. He estimates a roundtrip mission to the Martian moon Phobos, for example, could be made for less than $1 billion.

A space coach journey would also be more comfortable, McConnell added. The ship would carry large quantities of water, so astronauts could conceivably grow some food crops and — luxury of luxuries — even take hot baths now and again.

McConnell and co-author Alexander Tolley published their study last March in the Journal of the British Interplanetary Society.

A fleet of space coaches?

McConnell envisions space coaches cruising around the solar system, each individual vehicle fueling up with water in low-Earth orbit when the need arises. In the future, fuel could be sourced along a space coach’s travels — for example, water could be mined from an asteroid or a Martian moon.

Parts could be swapped out and upgraded on orbit as well, helping to keep the space coaches in good operating condition for several decades, McConnell said. Each mission undertaken from low-Earth orbit would be far cheaper than anything launching from the ground.

McConnell thinks an entire fleet of space coaches could one day populate the heavens, flying a variety of different flags — as long as somebody takes the initial plunge.

“If one party decides to do this, I think it would spur a lot of other activity,” McConnell said. “I think countries wouldn’t want to get left behind.”

From vision to reality

No huge technological leaps are required to make the space coach a reality, McConnell said. Bigelow’s expandable habitats are already space-tested, for example, as are several varieties of electrothermal engine.

“There’s not a lot of new technology that needs to be built,” McConnell said.

Electrothermal engines that use water as fuel, however, have not been flight-tested, so some work needs to be done on the propulsion system. McConnell envisions holding a design competition for the engines, as well as one for the overall ship design — cash-reward contests that would be like smaller versions of the Google Lunar X Prize, which is a $30 million private race to the moon.

Once winners of these competitions emerge, ground-testing and, eventually, flight-testing would follow. McConnell declined to put forth any specific timelines, but he’s optimistic about the possibilities.

“I think things could happen very quickly,” he said. “It’s really just a matter of convincing decision-makers that this is worth getting into.”

http://www.space.com/11230-water-powered-spaceship-mars-solar-system.html

How Dangerous Is Japan’s Nuclear Disaster?

The destroyed reactors at Fukushima have been releasing radiation for weeks. According to model calculations, the stricken nuclear plant could already have released one-tenth of the amount of radiation unleashed in the Chernobyl disaster. How serious a risk does the disaster pose to humans?

The technicians had for days to restore electricity to the remains of the Fukushima nuclear power plant. But then it was ordinary rubber boots, of all things, that would come to symbolize their desperation, helplessness and defeat.

On Thursday, the three men had made their way into the basement of the turbine building for reactor No. 3 to examine the situation there. When they returned later, they came fully equipped with tools and protective gear that included helmets, masks, rubber gloves and raincoats on top of their radiation suits.

The one thing the men were not prepared for was that suddenly they would be wading through more than a few inches of water. Two of the workers were only wearing ankle-high boots, which allowed the water to seep in. With wet feet, the men spent three-quarters of an hour working on the cables, despite the fact that their dosimeters were beeping for a long time.

The workers are now under observation at the National Institute of Radiological Sciences. The water at Fukushima was so contaminated that radioactive beta radiation burned their skin. In less than an hour, they were exposed to about 180 millisievert of radiation, or nine times as much as one nuclear power plant employee is exposed to in an entire year. “These kinds of burns will be causing problems for the men for a long time to come,” says Peter Jacob, director of the Institute for Radiation Protection at the Helmholtz Center in Munich, Germany. Commenting on the exposure, a coworker of the three men said laconically: “We do pay attention. But now we have to be even more careful as we work.”

The incident revealed, once again, how little experts know about the dangers that still lurk on the grounds of the ill-fated plant. No one had expected the radiation level in the water in the basement to be as high as it was. The levels of radiation in water in the basement of reactors No. 1, No. 2 and No. 3 reached record highs, with water at No. 2 measuring 1,000 millisieverts per hour. This was due to a partial core melt. Also, the containment vessel for the third reactor was apparently damaged, representatives of the Japanese nuclear regulatory agency concluded. Could this mean that there is a crack in the barrier between the highly radioactive core and the surrounding environment?

The beginning of last week offered grounds for cautious optimism. Power had been restored to the damaged reactor No. 1, a German concrete mixer was pumping water into the dangerously empty pool containing spent fuel rods in Unit 4, and there had been no explosions in the plant for an entire week. Two weeks after the disaster in Fukushima began, all of this sounded like good news.

‘An Ongoing, Massive Release of Radioactivity’

Meanwhile, however, the engineers have been forced to realize that they have made almost no headway in restoring the cooling system. By Friday night, pumps were still not working in any of the damaged reactors. Up to 45 tons of sea salt have apparently accumulated in the containment vessels, complicating the cooling effort. The salt is crystallizing in warm spots and creating an unwanted layer of insulation. The engineers planned to start flushing fresh water into the reactors on Friday afternoon. But the reactors are only one problem. There’s also the issue of the 3,450 spent fuel rods, which are red-hot, presumably severely damaged and exposed to the air in half-empty pools.

“We are experiencing an ongoing, massive release of radioactivity,” says Wolfram König, head of Germany’s Federal Office for Radiation Protection. “And everyone should know by now that this isn’t over by a long shot.” Nuclear expert Helmut Hirsch says: “All I hear is that people are wondering whether this will turn into a meltdown. But the thing is, it already is a partial meltdown.” The difference, in this case, is that Fukushima is a creeping disaster.

To make matters worse, the wind changed on Friday. Radioactive particles over the Pacific were now drifting westward across Japan. High levels of radiation were detected in vegetables, water and soil near the Fukushima plant.

The Japanese authorities have so far only evacuated a zone within 20 kilometers (12.4 miles) of Fukushima. But the risks posed by radiation are also growing for people outside this zone. “It is high time Japanese authorities extend the 20- kilometer (12.4-mile) evacuation zone around the crippled nuclear-power plant at Fukushima … Pregnant women and small children should immediately be evacuated from a progressively increasing area,” writes nuclear critic Mycle Schneider, lead author of the World Nuclear Industry Status Reports. Embryos, fetuses and infants are at the highest risk, because radiation targets cells that divide quickly.

 

There are currently 77,000 people living in emergency shelters set up in places like gymnasiums. Another 62,000 people live within the 30-kilometer zone. The head of the United States Nuclear Regulatory Agency (NRC) recommends expanding the evacuation zone to 80 kilometers, in which case 2 million people would have to be relocated — in addition to the hundreds of thousands of earthquake and tsunami victims. Japanese authorities are now asking people to leave the area voluntarily.

The beleaguered Japanese are also being peppered with concerned advice, demands and speculation from the United States, Russia, Finland and Germany. Even France’s nuclear safety agency IRSN, not exactly known for its cautionary approach to nuclear risks, published a disturbing model calculation last week. According to the report, by last Tuesday the Fukushima plant had already released into the environment one-tenth of the amount of radioactive material that was released at Chernobyl in 1986.

The International Atomic Energy Agency (IAEA), however, believes that this estimate is highly exaggerated. According to its calculations, which are based on readings taken by measuring equipment at the site, the amount of radiation released to date is only a fraction of the French estimate.

Part 2: Contaminated Food and Water

The French physicists and engineers based their assumptions on their knowledge of the amount of fissile material in the reactors, their own research on the condition of hot fuel rods and readings taken in the vicinity of Fukushima. German nuclear expert Helmut Hirsch, who has performed model calculations for Greenpeace, says: “This is not an exaggeration.” There are more than 2,500 tons of uranium and plutonium in Fukushima, a “gigantic radioactive inventory, at least 20 times as much as there was at Chernobyl,” says nuclear critic Schneider.

In fact, things could get even worse, much worse, than the French calculation suggests. The French scientists assume that most of the radioactive particles currently being measured come from reactor vessels 1, 2 and 3. The active fuel rods, which have hardly cooled at all, had caused temperatures in the containment vessels to rise so significantly than the plant engineers were forced to release radioactively contaminated air through valves in the interior of the reactors. In reactors in Germany and the United States, these emergency valves contain filters to capture radioactive particles. There were no such filters at the Fukushima plant.

Nevertheless, the best scenario, under the current circumstances, would have been to allow the radiation to reach the environment in this fashion. Indeed, the engineers at Fukushima have not had to release any more of this radioactive steam for more than a week now. If the French assumptions are correct, the worst emissions of radioactivity could already be over.

‘We Don’t Have the Slightest Idea of What Conditions Are Like’

Other experts support a different theory. Bill Borchardt of the NRC, for example, blames the high radiation values near Fukushima primarily on the spent fuel rods in the holding pools.

This would be a much more difficult problem to contain. The spent fuel rods, normally kept underwater and protected by the roof of the reactor building, are now emitting radiation to the open air. Only cooling water prevents the rods from igniting, and yet the cooling water is constantly turning into radioactive steam. Even more worrisome is the question of how it will be possible to ever refill the holding pools, which may have been damaged in the earthquake.

How much radioactivity is released also depends on the condition of the fuel element. A fuel element consists of about 100 four-meter-long fuel rods, each about as thick as a human thumb. The rods themselves are made of a zirconium alloy, which is filled with rounded tablets of uranium oxide, not unlike pills in a tube. Experts fear, however, that the metal shells could have become oxidized and have partially melted. If that is the case, larger amounts of fissile products are escaping from the rods.

Instruments in a helicopter flying over the plant measured 80 millisievert of radiation at an altitude of 40 meters (131 feet) above the roof of the plant, with levels dropping to only 4 millisievert 200 meters higher up. This suggests that the radiation is coming directly from the holding pools.

Could this assessment prove to be completely wrong? “I think we don’t have the slightest idea of what conditions are like in the reactor buildings,” says the NRC’s Borchardt.

Radiation Detected in Vegetables

As an American, Borchardt is familiar with the problem. After the reactor accident at Three Mile Island near Harrisburg, Pennsylvania in 1979, it took six years before engineers could open the reactor core. Only then were they able to see how far the meltdown had progressed. A monitoring system for such accidents is now required in the United States. It measures how much radioactivity is released, as well as the condition of the fuel rods. Japan has no such systems.

Instead Tepco, the plant’s operator, has published photos taken during the power outage. They show workers with flashlights and clipboards groping their way through the pitch-dark control room of reactor Units 1 and 2 to check measuring equipment.

Otherwise, the only alternative has been to read the smoke signals. Experts believe that dark smoke comes from burning cables and debris, while white smoke signifies water evaporating over the hot fuel elements.

Meanwhile, Tepco measured 500 millisievert per hour near the No. 2 reactor. Anyone who remains within this zone for 12 hours will die of radiation sickness. The radiation levels in proximity to the three exposed electricians were almost as high.

The eerie radiation has long since spread beyond the grounds of the nuclear plant. Food safety monitors measured 82,000 bequerel per kilogram in cabbage grown in a region 40 kilometers northwest of Fukushima. The maximum allowed value is 500. The highest readings measured in spinach were 54,000 bequerel per kilogram.

Experiences from Chernobyl show, once again, how long radioactivity can persist in the food chain. Some 25 years after the reactor accident, the meat from one in five wild boars hunters shoot in certain parts of Bavaria has to be thrown away, because it contains more than 1,000 bequerel per kilogram.

Japanese authorities have also found radioactive iodine in drinking water, although levels remain relatively low. Nevertheless, when the government recommended against using tap water to make infant formula, Tokyo supermarkets quickly sold out of bottled water. “There isn’t a single bottle left on the shelf,” reports Philip White of the Citizens Nuclear Information Center, the center of Japan’s cautious anti-nuclear movement.

Panic buying in Tokyo is already making it more difficult to provide drinking water to people in the areas hit by the tsunami, where many water lines were destroyed. But what happens if radiation in the drinking water reaches truly worrisome levels?

Part 3: Just How Reliable Are the Radiation Measurements?

The Japanese will have to learn to think in terms of millisievert. For example, the highest reported hourly dose at the edge of the evacuation zone was 0.16 millisievert. A person who spends 25 days constantly exposed to such levels would receive the maximum permissible annual dose for workers at nuclear power plants.

There is also an underlying sense of uncertainty over just how reliable the radiation measurements actually are. And critics wonder why the highest radiation readings near Fukushima are usually taken by police personnel and not Tepco or the Japanese nuclear regulatory agency.

But even if suspicions are unfounded, the insidious aspect of radiation is that it is so unpredictable. “We will see a patchwork of areas of higher and lower radiation levels,” says Peter Küppers of the Eco-Institute Darmstadt in southwestern Germany. The radiation level depends on wind direction, rain and where water collects. The differences were extreme after Chernobyl. “There were parts of northeast Bavaria and at Konigsberg Lake in Germany that were more contaminated than some spots within the 30-kilometer exclusion zone directly surrounding Chernobyl,” says Küppers.

Dispersal over such a large area can be practically ruled out in Japan. This only occurred at Chernobyl because the reactor burned for days, propelling radioactive material into extremely high air layers.

But where the fallout descends also depends largely on the wind in Japan. “At first Japan was very lucky, as far as the weather was concerned,” says König of Germany’s Federal Office for Radiation Protection. The sinister plumes initially drifted out to sea. But the weather gods will not always remain as merciful.

A Sense of Foreboding and Uncertainty

There is already a sense of foreboding among the residents of Fukushima. Yoshihiro Amano owned a small grocery store six kilometers from the nuclear power plant. Now he is waiting in line for a bowl of noodle soup in an evacuation center, trying to make the best of the situation. “There’s no point in getting angry,” he says. “But we are afraid. We don’t know if it will take days, months or decades before we can go home again.”

The Japanese will have to live with this uncertainty from now on, because our knowledge of the health effects of radioactive radiation is so appallingly slim.

Studies involving the survivors of Hiroshima and Nagasaki concluded that if 100 people received a dose of 100 millisievert, one of these people would eventually die of cancer as a result of the exposure.

This can certainly be seen as a comforting piece of news. On the one hand, it indicates that if about 40 of 100 Japanese would normally die of cancer at some point in their lives, that number would only rise to 41 among 100 people exposed to 100 millisievert of radiation. On the other hand, 100 millisievert is an enormous dose. To date, only a handful of workers in Japan have been exposed to such a bombardment of radioactivity.

But what about those who were exposed to lower levels of radiation? What if each of the 35 million residents of Tokyo is exposed to a few millisievert of radiation? There are few questions in science that are being discussed more heatedly, and yet there are no reliable answers.

‘Any Amount Is Harmful’

One thing is clear: Even in the region surrounding Chernobyl, there has been no statistically significant evidence of elevated levels of leukemia and cancer following the accident. The one exception is thyroid cancer in children, for which there is clear evidence of a connection with the accident. On the other hand, there is no official lower limit at which radiation becomes harmless. “Any amount is harmful,” says Edmund Enfolder, director of the Otto Hug Radiation Institute in Munich. “And the younger the person, the more harmful it is.”

Radiation poses the greatest danger to embryos in the womb during their earliest stages of development. Radiation can cause Down’s syndrome, spina bifida, cleft palate and other birth defects. Genetic changes can also be passed on to the next generation, as DNA testing of healthy children of the workers involved in the Chernobyl cleanup has shown.

According to the results of a disturbing simulation just released by the Japanese nuclear safety commission, young children outside the 30-kilometer radius surrounding the damaged nuclear power plant may have already absorbed a dose of 100 millisievert in their thyroid glands, as a result of the radioactive iodine leaked from the plant. In two-year-olds, this increases the risk of developing thyroid cancer by the age of 15 by a factor of five.

In the long term, the radioactive isotope cesium 137 is even more dangerous than radioactive iodine. It has a 30-year half-life and accumulates in the soil and in animals. “Cesium 137 becomes distributed throughout the body and can therefore promote cancer development in various places,” says Wolfgang-Ulrich Muller, a radiobiologist in the western German city of Essen.

It can take years or even decades until that happens. Nevertheless, Wolfram König, head of Germany’s Federal Office for Radiation Protection, is convinced that the radiation from the Fukushima nuclear power plant has already claimed its first victims — because of the fear of radiation and not the radiation itself. “It’s possible that many of the people who died in the rubble lost their lives because no one dared to help them,” says König.

Quelle:

http://www.spiegel.de/international/world/0,1518,753530,00.html

new technology: Artificial Leaf provides cheap energy

ANAHEIM, CALIFORNIA—Nearly all the energy we use on this planet starts out as sunlight that plants use to knit chemical bonds. Now, for the first time, researchers at the Massachusetts Institute of Technology have created a potentially cheap, practical artificial leaf that does much the same thing—providing a potentially limitless source of energy that’s easy to tap.

The new device is a silicon wafer about the shape and size of a playing card coated on either side with two different catalysts. The silicon absorbs sunlight and passes that energy to the catalysts to split water into molecules of hydrogen and oxygen. Hydrogen is a fuel that can be either burned or used in a fuel cell to create electricity, reforming water in either case. This means that in theory, anyone with access to water can use it to create a cheap, clean, and available source of fuel.

“It’s spectacular,” says Robert Grubbs, a chemist at the California Institute of Technology in Pasadena, who saw the presentation here yesterday at the biannual meeting of the American Chemical Society. “There’s still obviously a long way to go” to make the new device into a rugged, real-world technology, Grubbs says. But the approach is important because its potential low cost could make it widely available. It “has a chance of being scalable,” Grubbs says.

The new device isn’t the first semiconductor capable of splitting water. Over a decade ago, a team led by John Turner of the National Renewable Energy Laboratory in Golden, Colorado, created a gallium arsenide chip capable of splitting water, ultimately storing 12% of the energy in sunlight in hydrogen. But gallium arsenide is expensive, and the device quickly corroded in water, making it unusable.

Splitting water into its components of hydrogen and oxygen requires orchestrating two chemical reactions at the same time. Electrons must be stripped from hydrogen atoms in water, which causes water molecules to fracture into positively charged hydrogen ions, or protons, and negatively charged oxygen atoms. One catalyst then must knit together two oxygen atoms to form O₂, while a second catalyst welds two hydrogen atoms with two electrons to make H₂.

Three years ago, a team led by chemist Daniel Nocera of the Massachusetts Institute of Technology (MIT) in Cambridge solved half the problem with a special cobalt and phosphorus-based catalyst that knit O₂ molecules. This catalyst was unique in that it dissolves and reforms as part of its catalytic cycle. That behavior turned out to be a huge advantage, Nocera says. Although the catalyst corrodes during use, each time it starts over it’s working with a pristine noncorroded surface to continue the reaction.

Stitching together hydrogen atoms to create H₂ had its own roadblocks. Platinum works well, but it’s rare and expensive. Yesterday, Nocera reported devising a cheap catalyst that uses three different metals to form H₂, getting around the platinum problem.

Nocera didn’t reveal the makeup of the new catalyst, as the work is not yet published, and he is in the process of patenting it.

But Nocera did say that the three metals each have different roles. The first, like an active ingredient in a medicine, welds H₂ molecules together. The second initially helps lock the other two metals into an alloy that can be manipulated. Once the alloy is coated on a surface and exposed to water, this second metal dissolves, leaving behind the other two metals in a highly porous material. That creates extra surface area for the H₂ reaction to take place.

Normally, this reaction would be quickly doused thanks to phosphate ions that are present. So Nocera’s team added a third metal to drive phosphate away from the material’s surface and allowed the device to function continuously.

To make their artificial leaf, the MIT team spread its catalysts on opposite sides of a silicon wafer. The silicon absorbs sunlight and passes energetic, negatively charged electrons and positively charged electron vacancies to the catalysts on opposite sides that use them to make H₂ and O₂.

The solar collector is actually slightly more complex than a uniform slab of silicon. That was necessary because splitting water requires at least 1.23 volts, but a single silicon cell provides only about 0.5 volts. So the MIT team used a commercially available material with three silicon cells layered atop one another, giving them enough voltage to drive the water-splitting reaction.

When the device is placed in a clear jar and exposed to sunlight, it produces a steady stream of oxygen and hydrogen bubbling up to the surface. According to Nocera, the setup converts 5.5% of the energy in sunlight into hydrogen fuel. “You literally walk outside, hold it up, and it works,” Nocera says.

The new catalyst also appears highly stable. Nocera says his team has been operating the device for a week, using water from the nearby Charles River in Cambridge, without any drop in efficiency. The next step is to find out whether the device works equally well in seawater. If so, it could dramatically lower the cost of producing hydrogen fuel.

 

Source:

http://news.sciencemag.org/sciencenow/2011/03/spinning-the-suns-rays-into-fuel.html

Radiation in Fukushima reactor’s building tests 10 million times above normal

Tokyo (CNN) — Radiation levels in pooled water tested in the No. 2 nuclear reactor’s turbine building at the Fukushima Daiichi power plant are 10 million times normal, utility company and government officials said Sunday.

Hidehiko Nishiyama, an official with Japan’s nuclear and industrial safety agency, said the surface water showed 1,000 millisieverts of radiation. By comparison, an individual in a developed country is naturally exposed to 3 millisieverts per year, though Japan’s health ministry has set a 250 millisievert per year cumulative limit before workers must leave the plant.

“Certainly, we have to be concerned about the fact that the level of radiation is increasing,” said Nishiyama. “But at this point, we do not … envisage negative health impacts.”

The 10-million-times normal reading applies to radioactive iodine-134 found in the No. 2 building’s pooled water, according to the nuclear safety agency. This isotope loses half its radioactive atoms every 53 minutes, compared to a half-life of every eight days for radioactive iodine-131 that has also been detected in recent days.

Two people working in and around the No. 2 reactor when the test result became known, according to an official with the Tokyo Electric Power Company, which runs the plant. Those individuals subsequently left, and work there has stopped until the government signs off on the power company’s plan to address the issue.

Work has similar ceased at the No. 3 reactor, where tests earlier indicated radiation 10,000 times normal in its own turbine building.

On Sunday, water was being pumped out of the No. 1 reactor’s turbine building — a process that authorities eventually want to repeat in the other two reactors’ buildings with pooled, and contaminated, water.

Authorities are still trying to pinpoint the relationship, if any, between these alarming readings from inside these buildings to a continued spike in radiation detected in seawater just offshore.

A Japanese nuclear safety official said Sunday that levels of radiation were 1,850 times normal at a monitoring post situated 330 meters (361 yards) into the Pacific Ocean. This is near the discharge canal for the Nos. 1, 2, 3 and 4 reactors.

On Saturday, similar readings from the same monitoring posts showed readings were 1,250 times above normal. The previous day, they’d been lower — at 104 times more than a typical level.

This substance is a biproduct during the nuclear energy process, and officials suspect the seawater contamination may be a direct result of problems at the plant.

Up until Sunday, the potential for contamination from the No. 3 reactor had been a primary concern. This unit, which has had a building severely damaged by a hydrogen explosion and that an official said last week might have leaked radiation from its reactor core, is the only one of the facility’s six reactors to use a combination of uranium and plutonium fuel, called MOX. Experts say this mix is considered more dangerous than the pure uranium fuel used in other reactors.

Three men laying cable in the No. 3 unit turbine building’s basement have been hospitalized after stepping in the highly radioactive water there on Thursday.

An official with Tokyo Electric Power Company, which runs the plant, apologized Saturday, saying the exposure might have been avoided with better communication.

Hideyuki Koyama, the company’s associate director, said pooled water had been discovered in the basement of the No. 1 reactor six days earlier. But a sample was not taken for analysis until the 24th, after the three workers were exposed to between 173 to 181 millisieverts of radiation.

Such incidents threatened to undermine the public’s trust in Tokyo Electric, Japanese Chief Cabinet Secretary Yukio Edano told reporters.

He added the Japanese government “would like to give stronger instructions” to the company that it fully disclose as much information as possible about conditions at the plant.

“Every piece of information must be provided accurately and swiftly” to Japan’s nuclear and industrial safety agency, Edano said. “Without this communication, it’s very difficult for the government to (establish) proper safety measures.”

As important, the chief secretary said, was the need for Tokyo Electric to be upfront with the Japanese — millions of whom get power from the company and millions more of whom have been affected by radioactive emissions stemming from the crisis.

“We need to be sure that (Tokyo Electric) isn’t going to act in a way that will create distrust,” Edano said.

Koyama told reporters that radiation alarms went off while the three men were working, but they continued with their mission for 40 to 50 minutes after assuming it was a false alarm.

This continued debate about the working conditions for the roughly 500 individuals — among them utility workers, Japanese soldiers and firefighters from several cities — comes as work continued Sunday to cool nuclear fuel at the plant and prevent the further emission of radioactive material into the air and sea.

These was no immediate indication Sunday that issues with radiation in the two turbine buildings’ water had stopped the injection of fresh water into the Nos. 1, 2 and 3 reactor cores, a switch from the previous policy of pumping in seawater.

In addition, power and lighting were restored late Saturday afternoon to the No. 2 unit’s control room, according to an online update from the nuclear safety agency.

Those units have largely been authorities chief focus, since they were the only ones operating (and, thus, with nuclear fuel rods in the reactor cores) when the March 11 earthquake and subsequent tsunami hit.

Nishiyama said that fresh water should be injected into the No. 2 unit’s spent fuel pool on Monday and No. 1 unit’s spent fuel pool on Tuesday. Some nuclear fuel rods, which may have been fully or partially exposed, remain in these pools — meaning that, if they aren’t sufficiently cooled, the fuel rods have the potential to heat up and emit radiation into the atmosphere.

Fresh water should also be pumped, starting Monday, into the No. 4 unit’s nuclear fuel pool. This suffered possible damage and has been subject to frequent external spraying of seawater, given concerns that its water levels were low and fuel rods there may be fully or partially exposed.

Authorities have been trying to restart a steady supply of electricity to power the cooling systems, in order to control the temperatures of nuclear fuel and prevent further radioactive emissions, for that reactor and several other in the nuclear facility.

This has already occurred in the Nos. 5 and 6 units, which are considered stable. These units have fuel rods in spent fuel pools, but not in their reactor cores.

Highly Radioactive Water Leaking From Reactors at Fukushima Nuke Plant

Highly radioactive water was found leaking from two other reactors at the Fukushima Dai-ichi nuclear plant Friday after two employees were hospitalized when they waded into water 10,000 times more radioactive than normal.

The Tokyo Electric Power Co. told Kyodo News that it has begun injecting freshwater into the Unit 1 and 3 reactors at the plant, despite radioactive water leaking from Unit 1, 2 and 3.

The National Institute of Radiological Sciences says that the two employees have likely suffered “internal exposure” in which radioactive substances have entered their bodies, according to Kyodo News.

The possible breach in Unit 3 might be a crack or a hole in the stainless steel chamber of the reactor core or in the spent fuel pool that’s lined with several feet of reinforced concrete. The temperature and pressure inside the core, which holds the fuel rods, remained stable and was far lower than would further melt the core.

A Japanese government official told residents within 19 miles of the crippled plant to evacuate Friday.

Chief Cabinet Secretary Yukio Edano told a news conference that the government asked leaders of affected municipalities to encourage people to leave the affected areas, according to Kyodo News.

A somber Prime Minister Naoto Kan sounded a pessimistic note at a briefing hours after nuclear safety officials announced what could be a major setback in the urgent mission to stop the plant from leaking radiation, two weeks after a devastating earthquake and tsunami disabled it.

“The situation today at the Fukushima Dai-ichi power plant is still very grave and serious. We must remain vigilant,” Kan said. “We are not in a position where we can be optimistic. We must treat every development with the utmost care.”

The uncertain situation halted work at the nuclear complex, where dozens had been trying feverishly to stop the overheated plant from leaking dangerous radiation. The plant has leaked some low levels of radiation, but a breach could mean a much larger release of contaminants.

Kan apologized to farmers and business owners for the toll the radiation has had on their livelihoods: Several countries have halted some food imports from areas near the plant after milk and produce were found to contain elevated levels of radiation.

He also thanked utility workers, firefighters and military personnel for “risking their lives” to cool the overheated facility.

The alarm Friday comes two weeks to the day since the magnitude-9 quake triggered a tsunami that enveloped cities along the northeastern coast and knocked out the Fukushima reactor’s cooling systems.

Police said the official death toll jumped past 10,000 on Friday. With the cleanup and recovery operations continuing and more than 17,400 listed as missing, the final number of dead was expected to surpass 18,000.

The nuclear crisis has compounded the challenges faced by a nation already saddled with a humanitarian disaster. Much of the frigid northeast remains a scene of despair and devastation, with Japan struggling to feed and house hundreds of thousands of homeless survivors, clear away debris and bury the dead.

A breach could mean a leak has been seeping for days, likely since the hydrogen explosion at Unit 3 on March 14. It’s not clear if any of the contaminated water has run into the ground. Radiation readings for the air were not yet available for Friday, but detections in recent days have shown no significant spike.

But elevated levels of radiation have already turned up in raw milk, seawater and 11 kinds of vegetables, including broccoli, cauliflower and turnips. Tap water in several areas of Japan — including Tokyo — also showed radiation levels considered unsafe for infants, who are particularly vulnerable to cancer-causing radioactive iodine, officials said.

The scare caused a run on bottled water in the capital, and Tokyo municipal officials are distributing it to families with babies.

Previous radioactive emissions have come from intentional efforts to vent small amounts of steam through valves to prevent the core from bursting. However, releases from a breach could allow uncontrolled quantities of radioactive contaminants to escape into the surrounding ground or air.

Government spokesman Yukio Edano said “safety measures may not be adequate” and warned that may contribute to rising anxiety among people about how the disaster is being managed.

“We have to make sure that safety is secured for the people working in that area. We truly believe that is incumbent upon us,” the chief Cabinet secretary told reporters.

NISA spokesman Hidehiko Nishiyama said later that plant operator Tokyo Electric Power Co. was issued a “very strong warning” for safety violations and that a thorough review would be conducted once the situation stabilizes.

Another strong aftershock struck off Japan’s northeastern coast Friday. A magnitude-6.4 earthquake hit close to the epicenter of the massive March 11 earthquake and tsunami, the United States Geological Survey says.

Read more: http://www.foxnews.com/world/2011/03/25/dangerous-breach-suspected-japan-nuclear-plant/#ixzz1HewmeFZ8

Are Earthlings From Mars? New Tool May Reveal Your Alien Ancestry

It’s possible that the family tree of all life on Earth has its roots on Mars — and a new device could put that theory to the test in a few years, researchers say.

Researchers are developing an instrument that would search through samples of Martian dirt, isolating any genetic material from microbes that might be present — bugs that are living or that died relatively recently, within the last million years or so. Scientists could then use standard biochemical techniques to analyze any resulting genetic sequences, comparing them to what we find on Earth.

 

“It’s a long shot,” said MIT researcher Chris Carr, who’s working on the life-detecting device, in a statement. “But if we go to Mars and find life that’s related to us, we could have originated on Mars. Or if it started here, it could have been transferred to Mars.” [5 Bold Claims of Alien Life]

Either way, Carr added, “we could be related to life on Mars. So we should at least be looking for life on Mars that’s related to us.”

Ancient Martian life?

The idea that all Earth life could be descended from Martian organisms may not be fully mainstream — but it’s not too crazy to dismiss, either. While the Martian surface appears to be cold, dry and lifeless today, there is plenty of evidence that the planet was much warmer and wetter in the distant past, billions of years ago.

Here on Earth, life almost invariably occupies any niche that contains liquid water. So ancient Mars may have once supported some form of life — perhaps even before Earth did, researchers said.

If that’s the case, these Mars microbes may have colonized Earth, zipping through interplanetary space aboard rocks blasted off the Martian surface by asteroid impacts. An estimated 1 billion tons of Martian rock have made this journey over the years, researchers said.

And microbes are incredibly hardy, so it’s possible that some bugs could have survived the asteroid impact and the trip through space to a new planet, they added. Orbital dynamics show that it’s about 100 times easier for rocks to travel from Mars to Earth than the other way around, Carr said.

So if life got started on Mars first, it’s possible that every living thing on Earth can trace its lineage back to a Martian.

“It is not implausible that life on Mars will be related to life on Earth and therefore share a common genetics,” said astrobiologist Chris McKay of NASA’s Ames Research Center in Moffett Field, Calif. “In any case, it would be important to test this hypothesis.”

Digging through Martian dirt

The proposed instrument, being developed by researchers at MIT and Harvard, aims to do just that. The device — known as the Search for Extra-Terrestrial Genomes, or SETG — would take a sample of Martian soil and process it to separate out any possible organisms, living or dead (within the last million years or so).

While finding anything on the Martian surface might be a long shot, digging a little deeper could bear fruit; researchers have found evidence over the years that liquid water may lurk underground. [Video: The Changing Face of Mars]

Also, subterranean environments are more protected from the harmful ultraviolet radiation bombarding the Martian surface, making life more likely to survive underground.

“We think it’s much less likely that we would find something on the surface or in the top centimeters than if we went down a meter or more,” Carr told SPACE.com. “The deeper we could go on Mars, the better.”

So samples could be dredged up by a rover equipped with a deep drill. If any life-forms are present in the dirt, the SETG would amplify their DNA or RNA, then search for genetic sequences that are common in Earth organisms. Such analysis might be able to tell researchers how closely related any possible Martians are to us.

This would all be done on the Martian surface, without the need to lug dirt back to Earth, Carr said.

“But I would argue that it would sure be interesting to return samples if we found something,” he added.

The work is worth doing to better understand the origin and evolution of life on Earth, researchers said. But there are other, more practical reasons to look at the DNA of any potential Martians, too.

NASA and other space agencies, for example, would want to how much of a disease risk Martian organisms might pose to future astronauts.

“From an astronaut health and safety point of view and from a return-sample point of view, there is more to worry about” if there are organisms closely related to us on Mars, McKay said. For example, microbes that are similar to us are much more likely to have the chance to be infectious than totally alien organisms would be.

The SETG could also help detect biological contamination that spacecraft may have brought to Mars from Earth, Carr said.

The researchers presented a summary of their proposed life-detecting instrument earlier this month at the IEEE Aerospace Conference in Big Sky, Mont.

A few years away

The SETG is not yet ready to catch a rocket to Mars. A working version of the instrument will need to do three things: isolate biological material, amplify and detect DNA and then sequence it. Researchers have built a prototype instrument, about the size of a shoebox, that can perform the middle step, Carr said.

They’re working on adding the other two capabilities, and a fully functional prototype could be ready to go pretty soon.

“The goal is to have that system in two years, and then to put it through its paces in some challenging environments,” Carr said.

Such environments could include Antarctica or Chile’s Atacama Desert, Carr added. If the SETG passes its Martian-analog tests, the next step would be building a flight-ready instrument. If all goes well, that could happen by 2018 or so.

That timeline could make the SETG a candidate instrument for two rover missions slated to launch around 2018 — the European-led ExoMars and NASA’s Mars Astrobiology Explorer-Cacher (MAX-C). Both the ExoMars and MAX-C rovers will sport drills capable of getting at least a meter under the Martian surface.

Carr said such missions would be good fits for the SETG, but he stressed that the instrument hasn’t been selected for any Mars mission as of yet.

Ramping up the search for Martian life

If the SETG does get incorporated into a Mars mission, it would mark the first time that an instrument made its way to the Red Planet specifically to look for life since 1976, when NASA’s twin Viking landers found tantalizing, but ambiguous, results.

An instrument aboard NASA’s Mars Science Laboratory rover— also known as Curiosity — will investigate chemistry relevant to life when it arrives on the Red Planet in August 2012. The SETG, by contrast, directly addresses Earth-like molecular biology.

The SETG could someday have applications aside from searching for life on Mars, Carr said. For example, the tool could one day help astronauts diagnose infections in space and monitor their environments. But he hopes the instrument gets a chance to show its stuff on the Red Planet.

“Mars may or may not have life,” Carr said. “If it does, we think there’s a chance it could be related to us. If in fact it is, we want to find it.”

http://www.space.com/11209-mars-earth-life-origins-evolution.html

Fukushima’s thirth reactor core may be leaking radioactive material, official says

 

Tokyo (CNN) — Authorities in Japan raised the prospect Friday of a likely breach in the all-important containment vessel of the No. 3 reactor at the stricken Fukushima Daiichi nuclear power plant, a potentially ominous development in the race to prevent a large-scale release of radiation.

Contaminated water likely seeped through the containment vessel protecting from the reactor’s core, said Hidehiko Nishiyama of the Japan nuclear and industrial safety agency.

Three men working inside the No. 3 reactor stepped into water this week that had 10,000 times the amount of radiation typical for that locale, Nishiyama said. That water likely indicates “some sort of leakage” from the reactor core, signaling a possible break of the containment vessel that houses the core.

The containment vessel is designed to prevent radioactive material from escaping into the atmosphere, even if other parts of the reactor are damaged. A rupture in the containment vessel could pose problems for workers who are trying to prevent that, depending on its severity.

The three workers who were exposed to radiation by stepping in the contaminated water had the highest levels of radiation recorded so far, said Tokyo Electric Power Co., which owns the plant.

The incident raised questions about radiation control measures at the plant as 536 people — including government authorities and firefighters — continued working there Friday, according to an official with Tokyo Electric.

Workers are undertaking various measures to prevent the further release of radioactive substances into the air and beyond.

Some 17 people have been exposed to 100 or more millisieverts of radiation since the plant’s crisis began two weeks ago following a 9.0-magnitude earthquake and subsequent tsunami struck.

A person in an industrialized country is naturally exposed to 3 millisieverts of radiation a year.

But Japan’s Health Ministry recently raised the maximum level of exposure for a person working to address the crisis at the nuclear plant from 100 millisieverts to 250 millisieverts per year.

The workers had been laying cables in the No. 3 reactor turbine building’s basement when they stepped in the water. It seeped into the ankle-height boots of two, according to the power company.

The workers remained in the 15-centimeter (5-inch) deep water for about 40 to 50 minutes.

Two of them were admitted to Japan’s National Institute of Radiological Sciences: one in his 30s who was exposed to 180.7 millisieverts and the other in his 20s who tested at 179.37 millisieverts.

Nishiyama said the third man — who was exposed to 173 millisieverts but at first did not go to the hospital because his boots were high enough to prevent water from touching his skin — has also gone to the same research hospital out of “an abundance of caution.”

The water in this location is typically boiled and has low levels of radiation, Nishiyama said.

The high measure prompted a top official with Nishiyama’s agency to urge Tokyo Electric to “improve its radiation management measures.”

The No. 1 reactor remains a chief concern, with the Japan Atomic Industrial Forum noting Friday that its containment vessel was experiencing “increased” pressure.

Earlier, buildups of hydrogen gas had driven up pressure that led to explosions at three of the nuclear plant’s reactors, including the No. 1 unit.

Nishiyama conceded that “controlling the temperature and pressure has been difficult” for that reactor. Still, he told reporters Friday that the situation then was “rather stable,” given indications the pressure was decreasing.

As to that unit’s spent nuclear fuel pool, Nishiyama said the hope is to start pumping in fresh water — rather than seawater, as has been done.

Such pools, which are distinct but tied to a given reactor, have nuclear fuel rods that can emit radiation especially if they heat, which is more likely to happen without any functional cooling system in place and when the rods are not fully covered in water.

Switching to fresh water, instead of seawater, is also a priority for the No. 2 reactor’s core (as well as for its spent fuel pool), said Nishiyama. The aim is to prevent further corrosion and damage inside, which may be worsened by the buildup of salt.

Beyond the seawater/saltwater issue, water in and around the Nos. 1 and 2 reactors had “high radiation levels,”Nishiyama said Friday — though not as high as that of the No. 3 unit.

Thursday’s incident has further made the latter reactor a prime focus, and Nishiyama said Friday that “radiation levels are high” in some locales near that unit.

He said that authorities were considering “other routes” to accomplish their goals of restarting its cooling systems around No. 3, keeping its spent nuclear fuel pool in check and other aims. Later in the day, Nishiyama said authorities hadn’t yet determined how to get around the obstacle.

To this end, firefighters from Tokyo and Kawasaki were expected to resume spraying toward the No. 3 reactor and its fuel pool on Friday afternoon, according to Nishiyama.

Efforts are ongoing, too, on the Nos. 4, 5 and 6 reactors — each of which have their own concerns, though less pronounced because the units were on scheduled outages when the quake struck. None of these three units had nuclear fuel inside their reactors, though efforts are ongoing to control temperatures inside the spent fuel pools.

On Friday morning, a concrete pump truck was used once again to inject seawater into the No. 4 unit’s fuel pool.

 

source

http://edition.cnn.com/2011/WORLD/asiapcf/03/25/japan.nuclear.reactors/index.html?hpt=T1