TEHRAN, April 11 (Reuters) - Iran plans to build "four to five" nuclear research reactors and will continue to enrich uranium to provide their fuel, a nuclear official said on Monday despite Western pressure on Tehran to curb atomic work.
The head of Iran's Atomic Energy Organisation, Fereydoon Abbasi, said Tehran would build the reactors "in the next few years" to produce medical radioisotopes, according to the students news agency ISNA.
"To provide the fuel for these (new) reactors, we need to continue with the 20 percent enrichment of uranium," ISNA quoted him as saying.
Abbasi's remarks are likely to deepen Western fears that Iran's atomic work is aimed at building nuclear weapons.
Tehran says its nuclear programme is entirely peaceful and has dismissed international sanctions that were tightened last year as illegal.
Talks with major powers aimed at resolving the nuclear impasse stalled in January, with Tehran insisting it would not accept any attempt to curtail its nuclear enrichment activities.
Experts have previously said Tehran has stockpiled low-enriched uranium (LEU) and has enough for at least two atomic bombs if it was refined to a much higher level.
Abbasi also said the country would increase the amount of its uranium enriched up to 20 percent whenever needed.
"We will also raise the amount of the enriched uranium up to 20 percent based on our country's need and for doing so, we will not seek anybody's permission," he said.
Iran, a major oil producer, says it wants only LEU for the running of nuclear power plants to boost its electricity supply.
The U.N. Security Council has imposed four rounds of sanctions on Iran, reiterating its demand that it suspend enrichment. The Islamic Republic has also been hit by more far- reaching sanctions imposed by the United States and the EU.
On Saturday, Abbasi said "second and third generation" centrifuges -- the machines which enrich uranium to a purity needed in nuclear reactors, or, if to a high enough level, nuclear weapons -- had been produced and tested. (Writing by Zahra Hosseinian, editing by Alison Williams)
Monday, April 11, 2011
Iran to build new nuclear research reactors-report
Reuters: Iran to build new nuclear research reactors-report
Three Nebraska nuclear workers exposed to radiation
Reuters: Three Nebraska nuclear workers exposed to radiation
(Reuters) - The U.S. nuclear safety regulator said on Monday it is investigating how three workers at a nuclear power plant in Nebraska were accidentally exposed to radiation last week.
The three workers triggered radiation alarms by incorrectly moving a radioactive tube on April 3. They immediately set the tube down and fled the area.
Nebraska Public Power District, which operates the Cooper Nuclear Station, does not believe the workers were exposed to radiation above regulatory limits, the Nuclear Regulatory Commission said in a release.
"We want to understand why normal work practices were not followed, resulting in unplanned radiation exposures to three workers," said regional NRC administrator Elmo Collins.
NRC inspectors will calculate the workers' exposures and look at how the incident occurred and was handled. Its report on the event will be available within 45 days.
The plant is located near Brownville, Nebraska, 75 miles south of Omaha.
Nuclear safety has been under the spotlight since a massive earthquake and tsunami damaged nuclear reactors in Japan and released radiation into the surrounding area last month. Japan is still struggling to contain the leaks.
(Reuters) - The U.S. nuclear safety regulator said on Monday it is investigating how three workers at a nuclear power plant in Nebraska were accidentally exposed to radiation last week.
The three workers triggered radiation alarms by incorrectly moving a radioactive tube on April 3. They immediately set the tube down and fled the area.
Nebraska Public Power District, which operates the Cooper Nuclear Station, does not believe the workers were exposed to radiation above regulatory limits, the Nuclear Regulatory Commission said in a release.
"We want to understand why normal work practices were not followed, resulting in unplanned radiation exposures to three workers," said regional NRC administrator Elmo Collins.
NRC inspectors will calculate the workers' exposures and look at how the incident occurred and was handled. Its report on the event will be available within 45 days.
The plant is located near Brownville, Nebraska, 75 miles south of Omaha.
Nuclear safety has been under the spotlight since a massive earthquake and tsunami damaged nuclear reactors in Japan and released radiation into the surrounding area last month. Japan is still struggling to contain the leaks.
Friday, April 8, 2011
Democrat pans plan to visit Yucca nuclear dump
Reuters: Democrat pans plan to visit Yucca nuclear dump
(Reuters) - A top U.S. Democratic lawmaker on Friday slammed a Republican plan to visit the shuttered Yucca Mountain nuclear waste dump site, calling the trip a "needless" expense.
Representative Henry Waxman, the top Democrat on the House Energy and Commerce committee, urged lawmakers to cancel the trip to the controversial site after the Energy Department said it would cost at least $200,000.
"At a time when the government is facing a shutdown over funding, it seems completely inappropriate to incur these needless expenses," Waxman said in a letter to John Shimkus, the head of an Energy and Commerce subcommittee.
Waxman's letter was the latest round in a political fight over Nevada's Yucca Mountain dump site, which was supposed to permanently house the nation's nuclear waste.
The Obama administration shelved the proposed dump in 2009, after years of opposition from Nevada residents, leaving the country without a site to store radioactive waste long term.
That decision has run into stiff opposition from Republican lawmakers, though, who say the administration has an obligation to move ahead with the site, which was approved by Congress.
With the Japanese nuclear crisis reigniting the debate over how the United States should handle its nuclear waste, Shimkus and Energy and Commerce committee chairman Fred Upton launched a probe late last month into the cancellation of the radioactive waste dump.
Shimkus also informed the Energy Department that committee members planned to tour the site.
Waxman said the department would have to spend at least $200,000 to transport lawmakers to the mountain and do the testing necessary to reopen the site after nearly two years.
The focus on spending comes as a battle over the budget in Congress threatened to shut down the U.S. government on Friday, with Democrats and Republicans struggling to strike a deal on spending cuts by midnight.
(Reuters) - A top U.S. Democratic lawmaker on Friday slammed a Republican plan to visit the shuttered Yucca Mountain nuclear waste dump site, calling the trip a "needless" expense.
Representative Henry Waxman, the top Democrat on the House Energy and Commerce committee, urged lawmakers to cancel the trip to the controversial site after the Energy Department said it would cost at least $200,000.
"At a time when the government is facing a shutdown over funding, it seems completely inappropriate to incur these needless expenses," Waxman said in a letter to John Shimkus, the head of an Energy and Commerce subcommittee.
Waxman's letter was the latest round in a political fight over Nevada's Yucca Mountain dump site, which was supposed to permanently house the nation's nuclear waste.
The Obama administration shelved the proposed dump in 2009, after years of opposition from Nevada residents, leaving the country without a site to store radioactive waste long term.
That decision has run into stiff opposition from Republican lawmakers, though, who say the administration has an obligation to move ahead with the site, which was approved by Congress.
With the Japanese nuclear crisis reigniting the debate over how the United States should handle its nuclear waste, Shimkus and Energy and Commerce committee chairman Fred Upton launched a probe late last month into the cancellation of the radioactive waste dump.
Shimkus also informed the Energy Department that committee members planned to tour the site.
Waxman said the department would have to spend at least $200,000 to transport lawmakers to the mountain and do the testing necessary to reopen the site after nearly two years.
The focus on spending comes as a battle over the budget in Congress threatened to shut down the U.S. government on Friday, with Democrats and Republicans struggling to strike a deal on spending cuts by midnight.
Nuclear Crisis Fuels Duel at Diablo
The Wall Street Journal: Nuclear Crisis Fuels Duel at Diablo
Japan's unfolding reactor crisis is fueling a battle over nuclear power across the Pacific, in earthquake-prone California.
Pacific Gas & Electric Co., the big California utility, is seeking a 20-year license extension for its two reactors at Diablo Canyon, a nuclear power plant near San Luis Obispo, on the state's central coast.
That application, controversial even before an earthquake and tsunami crippled Japan's Fukushima Daiichi plant last month, is now shaping up as a major test of Americans' tolerance of nuclear power, especially in areas at high risk for natural disasters.
Local politicians are lining up to fight the license extension, arguing that the process should be put on hold while PG&E studies the area's earthquake risk.
"The tragedy in Japan underscores the importance and critical evidence of the need for a pause in relicensing," said Rep. Lois Capps (D., Calif.), who last month asked regulators to delay renewing Diablo's license.
National anti-nuclear groups, too, are making the Diablo case a focal point of their broader fight against nuclear power. "Diablo Canyon is just a striking and scary example of playing with some seriously explosive fire," said Sean Garren of the activist group Environment America.
Dozens of nuclear reactors operate in earthquake-prone regions around the world. Among them, least 34 are in high-hazard areas. See a map and database of all of them.
Opponents may have trouble making much headway with the federal agency that oversees nuclear relicensing, the Nuclear Regulatory Commission. The NRC sets strict limits on what issues can be considered in the relicensing, and has consistently rebuffed efforts to use the process to conduct broad-based reviews of plants' operations.
PG&E says Diablo Canyon is safe and was built to withstand earthquakes. James Becker, PG&E's vice president in charge of the plant, says the company is studying its ability to withstand bigger-than-expected quakes following the Japanese disaster.
"We're not done learning from the Japanese situation," Mr. Becker said. "We will apply the lessons learned wherever they fall."
Like the Daiichi plant, the Diablo plant sits on the coast and in a high-risk seismic area, but the reactors are not the same type.
Diablo Canyon has received the NRC's highest possible safety rating in each of the past ten years. Last year, however, the commission raised concerns about how workers evaluate problems at the plant, and in a letter last month it said PG&E's efforts to address the issue, "have not yet proven effective."
PG&E said it was "committed to working with NRC inspectors to resolve any existing concerns and to enhance the way we identify matters at the plant and track them to completion."
Many of those applications will be controversial, especially after the Fukushima crisis raised new questions about the safety of aging reactors.
But Diablo is drawing particular scrutiny because of its location in one of the country's most seismically active areas and its long, troubled history of trying to deal with the risk of a major quake.
In the early 1970s, while the plant was under construction, scientists discovered a new offshore fault less than three miles away, forcing a major redesign and pushing the project billions of dollars over budget. A construction error on key seismic supports led to another costly retrofit. And in 2008, scientists discovered yet another fault, this one less than a mile from the plant.
Even before the recent Japanese quake, local leaders, led by geophysicist-turned-Republican State Senator Sam Blakeslee, were demanding new studies of the plant's earthquake risk using modern seismic-imaging technology.
PG&E agreed to do the study, but rejected calls to put the relicensing process on hold until it is completed. Some question whether the company wants to get its license, originally issued in the 1980s, renewed before the studies reveal any problems. The existing 40-year licenses for the plant's two reactors don't expire until 2024 and 2025.
"It's almost a rush to judgment to submit their application for relicensing," said James Boyd, vice chairman of the California Energy Commission, a state agency. PG&E says the early application is simply prudent planning.
"If the plant wasn't going to be extended, we'd want to know well ahead of time so we can make plans for other resources," said PG&E's Mr. Becker.
The license-renewal process takes at least two years, and often longer in controversial cases. But the scope of the process is quite narrow. The NRC says it looks only at two issues in license renewal: the environmental impact of keeping the plant running, and the plant's management of aging equipment.
Non-age-related safety issues, such as earthquake risk, aren't considered in the renewal process. The commission says it constantly reviews those issues and orders plants to make changes when problems come to light.
Commission spokesman Scott Burnell said if the seismic studies reveal the need for changes at the plant, PG&E will have to make those changes immediately.
But some critics, including Rep. Capps, are pressuring the Commission to halt re-licensing until the seismic studies are complete.
Some plant critics are trying to do an end-run around the NRC by going to the California Public Utilities Commission, which regulates the state's power market. PG&E has asked the agency for permission to spend $80 million on the license-renewal process and to pass those costs on to its customers. Local groups are asking the commission to reject the request until the seismic studies are complete.
Japan's unfolding reactor crisis is fueling a battle over nuclear power across the Pacific, in earthquake-prone California.
Pacific Gas & Electric Co., the big California utility, is seeking a 20-year license extension for its two reactors at Diablo Canyon, a nuclear power plant near San Luis Obispo, on the state's central coast.
That application, controversial even before an earthquake and tsunami crippled Japan's Fukushima Daiichi plant last month, is now shaping up as a major test of Americans' tolerance of nuclear power, especially in areas at high risk for natural disasters.
Local politicians are lining up to fight the license extension, arguing that the process should be put on hold while PG&E studies the area's earthquake risk.
"The tragedy in Japan underscores the importance and critical evidence of the need for a pause in relicensing," said Rep. Lois Capps (D., Calif.), who last month asked regulators to delay renewing Diablo's license.
National anti-nuclear groups, too, are making the Diablo case a focal point of their broader fight against nuclear power. "Diablo Canyon is just a striking and scary example of playing with some seriously explosive fire," said Sean Garren of the activist group Environment America.
Dozens of nuclear reactors operate in earthquake-prone regions around the world. Among them, least 34 are in high-hazard areas. See a map and database of all of them.
Opponents may have trouble making much headway with the federal agency that oversees nuclear relicensing, the Nuclear Regulatory Commission. The NRC sets strict limits on what issues can be considered in the relicensing, and has consistently rebuffed efforts to use the process to conduct broad-based reviews of plants' operations.
PG&E says Diablo Canyon is safe and was built to withstand earthquakes. James Becker, PG&E's vice president in charge of the plant, says the company is studying its ability to withstand bigger-than-expected quakes following the Japanese disaster.
"We're not done learning from the Japanese situation," Mr. Becker said. "We will apply the lessons learned wherever they fall."
Like the Daiichi plant, the Diablo plant sits on the coast and in a high-risk seismic area, but the reactors are not the same type.
Diablo Canyon has received the NRC's highest possible safety rating in each of the past ten years. Last year, however, the commission raised concerns about how workers evaluate problems at the plant, and in a letter last month it said PG&E's efforts to address the issue, "have not yet proven effective."
PG&E said it was "committed to working with NRC inspectors to resolve any existing concerns and to enhance the way we identify matters at the plant and track them to completion."
Many of those applications will be controversial, especially after the Fukushima crisis raised new questions about the safety of aging reactors.
But Diablo is drawing particular scrutiny because of its location in one of the country's most seismically active areas and its long, troubled history of trying to deal with the risk of a major quake.
In the early 1970s, while the plant was under construction, scientists discovered a new offshore fault less than three miles away, forcing a major redesign and pushing the project billions of dollars over budget. A construction error on key seismic supports led to another costly retrofit. And in 2008, scientists discovered yet another fault, this one less than a mile from the plant.
Even before the recent Japanese quake, local leaders, led by geophysicist-turned-Republican State Senator Sam Blakeslee, were demanding new studies of the plant's earthquake risk using modern seismic-imaging technology.
PG&E agreed to do the study, but rejected calls to put the relicensing process on hold until it is completed. Some question whether the company wants to get its license, originally issued in the 1980s, renewed before the studies reveal any problems. The existing 40-year licenses for the plant's two reactors don't expire until 2024 and 2025.
"It's almost a rush to judgment to submit their application for relicensing," said James Boyd, vice chairman of the California Energy Commission, a state agency. PG&E says the early application is simply prudent planning.
"If the plant wasn't going to be extended, we'd want to know well ahead of time so we can make plans for other resources," said PG&E's Mr. Becker.
The license-renewal process takes at least two years, and often longer in controversial cases. But the scope of the process is quite narrow. The NRC says it looks only at two issues in license renewal: the environmental impact of keeping the plant running, and the plant's management of aging equipment.
Non-age-related safety issues, such as earthquake risk, aren't considered in the renewal process. The commission says it constantly reviews those issues and orders plants to make changes when problems come to light.
Commission spokesman Scott Burnell said if the seismic studies reveal the need for changes at the plant, PG&E will have to make those changes immediately.
But some critics, including Rep. Capps, are pressuring the Commission to halt re-licensing until the seismic studies are complete.
Some plant critics are trying to do an end-run around the NRC by going to the California Public Utilities Commission, which regulates the state's power market. PG&E has asked the agency for permission to spend $80 million on the license-renewal process and to pass those costs on to its customers. Local groups are asking the commission to reject the request until the seismic studies are complete.
Lack of Data Heightens Japan’s Nuclear Crisis
New York Times: Lack of Data Heightens Japan’s Nuclear Crisis
TOKYO — Nearly one month after Japan’s devastating nuclear accident, atomic energy experts, regulators and politicians around the world are still puzzling over a basic question: How much danger is still posed by the Fukushima Daiichi nuclear power plant?
That depends to a considerable extent on how hot the uranium fuel rods at the power plant remain, and whether fuel has escaped its containment, or might still do so. Yet remarkably little is known for sure about what is really happening inside the reactors because some areas remain far too radioactive for workers to approach, and some instruments have malfunctioned.
The paucity of data and the conflicting estimates of what the available information really means have prompted a series of confusing analyses and a rift between officials in Japan and those overseas — and even between one member of Congress and the United States Nuclear Regulatory Commission.
The commission speculated this week that the nuclear fuel in the core of one of the stricken reactors had probably leaked from its thick steel pressure vessel, its most important protective barrier. If that proved to be accurate, it would raise the prospect of continuing fuel leaks and high levels of radioactive releases that would vastly complicate containment and the cleanup.
But Japanese officials said there was no evidence of a compromised pressure vessel, and they wondered why they were reading about it in the newspapers.
“If they have a concern, they should inform us,” said Kentaro Morita of Japan’s nuclear regulatory body, the Nuclear and Industrial Safety Agency, after its American counterpart sounded the alarm over a possible nuclear fuel leak at the plant’s Reactor No. 2, clearly contradicting Japanese accounts. “They didn’t say such concerns to us directly,” Mr. Morita said.
A senior Foreign Ministry official, meanwhile, accused the foreign media of exaggerating the threat posed by the power plant and the radiation spreading from it. Radiation fears are hurting sales of Japanese products abroad.
Who is proved right in the scientific debate has great repercussions for how and when the nuclear crisis might be brought under control, and the potential implications if assumptions prove wrong.
From the start there have been differences, with the American authorities expressing a more pessimistic view than the Japanese.
The United States has advised Americans to stay at least 50 miles away from the Fukushima Daiichi plant. Japanese officials evacuated residents within a 12-mile radius, and have since said they are considering expanding the evacuation zone.
An assessment in late March by the Nuclear Regulatory Commission said that hydrogen explosions at the plant might have blown particles of nuclear fuel from the reactors’ spent-fuel pools up to a mile away. The Tokyo Electric Power Company, the operator of the Fukushima Daiichi plant, says that while the pools remain exposed at the most-damaged reactors, the fuel remains safely inside.
American officials are also concerned that mounting stresses on the reactors’ containment structures as they fill up with radioactive water used in emergency cooling make them vulnerable to rupture in an aftershock from the March 11 earthquake. Japanese officials have played down that concern, and on Friday they said a sizable aftershock that struck overnight had caused no further damage at the plant.
The rift also highlights the difficulty of a debate in which both sides are forced to extrapolate possible situations with little access to crucial readings from inside the reactors.
Much of the automated measurement equipment in the reactors has been damaged, either by explosions in the early days of the crisis or by intense radiation since then. Damage to the reactors, as well as high radiation, has prevented technicians from making detailed assessments.
The Pentagon has provided airborne surveillance drones that can help monitor ground-level radiation at the plant. It is possible that American officials are basing their analysis on data they have collected independently, though Obama administration officials say they have shared their information with the Japanese.
Even so, it is not easy to explain why such different theories are being offered on fundamental questions like whether radioactive fuel from the steel reactor pressure vessel at Unit No. 2 is leaking into the bottom of the containment structure.
The Nuclear Regulatory Commission cited high levels of radiation at one spot inside the containment structure at Reactor No. 2 as evidence for its analysis. In addition, extremely high levels of radiation were detected in the water from a recently stanched leak that ran from the reactor building into a drainage ditch and into the ocean.
The Japanese flatly deny that possibility. “At this moment we do not have any data that shows there has been leakage to the containment vessels,” said Hidehiko Nishiyama, deputy director general at the Japanese regulatory agency. He also said that the Japanese and American regulators, who talk every day, were no longer so far apart on this question.
Japanese officials believe that water pumped into the reactor to cool it — as opposed to the nuclear fuel itself — might have somehow leaked out. In addition, there is evidence that an explosion may have breached the primary containment structure, which may have allowed highly radioactive water into other parts of the plant and into the ocean.
Domestic political priorities appear to be driving at least some of the reactions in both countries. In the aftermath of the 1979 accident at Three Mile Island in Pennsylvania, nuclear regulators in the United States have often planned for and talked about the worst possibilities to avoid accusations that they are lax about safety.
The pressure on American officials to give well-rounded explanations about the potential threat remains high. In fact, some members of Congress who are critics of the nuclear power industry are skeptical that the regulatory commission has been as forthcoming as it should be about the risks posed by Japan’s nuclear crisis or the potential impact on American nuclear power plants that use similar technology.
This week, Representative Edward J. Markey, Democrat of Massachusetts, an outspoken critic, engaged in a running debate with members of the commission’s staff over the conditions at Reactor No. 2 in Japan. Mr. Markey said the regulators had told his staff that fuel was leaking from the reactor, but then the commission issued a more ambiguous public statement.
“I find it rather curious that some within the Nuclear Regulatory Commission are attempting to deny the findings their own technical staff conveyed to my office as soon as it became clear that this information showed a meltdown that is more severe than some people apparently wish to acknowledge,” Mr. Markey said in a statement.
On the Japanese side, officials have an obvious desire to avoid causing panic in public statements.
“We have a very conservative culture in the nuclear industry” in the United States, said Murray E. Jennex, a professor at San Diego State University and a specialist in nuclear containment structures. “There’s nothing to gain by the N.R.C. saying things are good. At the same time, there’s nothing to gain by Tokyo Electric not downplaying stuff.”
The Americans also appear to rely more heavily on complex computer programs like Melcor that use available data to extrapolate conditions in reactors after accidents. But the regulatory commission appears to have partly relied on data provided by Tokyo Electric, something that engineers skeptical of the power company say compromises the validity of the findings.
“When the input numbers are no good, the output numbers are no good,” said Satoshi Sato, a former engineer at General Electric, which designed the reactors at Fukushima Daiichi. He argues that the conditions in the reactors are probably worse than the Japanese have reported.
The Japanese also seem to prefer presenting raw data without explaining what they think it means, said Takashi Inoue, a professor of public relations at Waseda University. Every day, Tokyo Electric, the nuclear agency, the chief cabinet secretary and others hold news conferences at which they present a blizzard of facts and numbers but rarely make broader declarations about the conditions at Fukushima Daiichi.
Industry experts are split.
Yoichi Kikuchi, a Japanese nuclear engineer who helped design the containment vessel at one of the Fukushima Daiichi reactors, agreed with the Americans that a fuel leak was possible. He said that the pressure vessel at Reactor No. 2 was especially vulnerable because of openings at the bottom where control rods are inserted. If the fuel were melting, the metal welding around those openings would easily give way, allowing the fuel to travel into the drywell, he said. The fuel could then react with the water in the suppression chamber, setting off a vapor explosion and a huge release of radiation into the air, he said.
Shuichi Iwata, a nuclear fuel expert at Tokyo University, said that he thought a leak of fuel was probably occurring, but that the consequences might not be great. “The worst case is not happening, I think,” he said.
But Toshihiro Yamamoto, an associate professor in nuclear engineering at the Kyoto University Research Reactor Institute, said the nuclear agency’s explanation was more likely. He said that it was water, not fuel, escaping from the same openings, or perhaps from a damaged circulation pump higher in the vessel.
Masashi Goto, a former Toshiba nuclear power plant designer, said that Japanese officials appeared to have decided that they gained nothing but panic from predicting outcomes. “They will never speak about the worst-case scenario,” he said. “They will never predict.”
TOKYO — Nearly one month after Japan’s devastating nuclear accident, atomic energy experts, regulators and politicians around the world are still puzzling over a basic question: How much danger is still posed by the Fukushima Daiichi nuclear power plant?
That depends to a considerable extent on how hot the uranium fuel rods at the power plant remain, and whether fuel has escaped its containment, or might still do so. Yet remarkably little is known for sure about what is really happening inside the reactors because some areas remain far too radioactive for workers to approach, and some instruments have malfunctioned.
The paucity of data and the conflicting estimates of what the available information really means have prompted a series of confusing analyses and a rift between officials in Japan and those overseas — and even between one member of Congress and the United States Nuclear Regulatory Commission.
The commission speculated this week that the nuclear fuel in the core of one of the stricken reactors had probably leaked from its thick steel pressure vessel, its most important protective barrier. If that proved to be accurate, it would raise the prospect of continuing fuel leaks and high levels of radioactive releases that would vastly complicate containment and the cleanup.
But Japanese officials said there was no evidence of a compromised pressure vessel, and they wondered why they were reading about it in the newspapers.
“If they have a concern, they should inform us,” said Kentaro Morita of Japan’s nuclear regulatory body, the Nuclear and Industrial Safety Agency, after its American counterpart sounded the alarm over a possible nuclear fuel leak at the plant’s Reactor No. 2, clearly contradicting Japanese accounts. “They didn’t say such concerns to us directly,” Mr. Morita said.
A senior Foreign Ministry official, meanwhile, accused the foreign media of exaggerating the threat posed by the power plant and the radiation spreading from it. Radiation fears are hurting sales of Japanese products abroad.
Who is proved right in the scientific debate has great repercussions for how and when the nuclear crisis might be brought under control, and the potential implications if assumptions prove wrong.
From the start there have been differences, with the American authorities expressing a more pessimistic view than the Japanese.
The United States has advised Americans to stay at least 50 miles away from the Fukushima Daiichi plant. Japanese officials evacuated residents within a 12-mile radius, and have since said they are considering expanding the evacuation zone.
An assessment in late March by the Nuclear Regulatory Commission said that hydrogen explosions at the plant might have blown particles of nuclear fuel from the reactors’ spent-fuel pools up to a mile away. The Tokyo Electric Power Company, the operator of the Fukushima Daiichi plant, says that while the pools remain exposed at the most-damaged reactors, the fuel remains safely inside.
American officials are also concerned that mounting stresses on the reactors’ containment structures as they fill up with radioactive water used in emergency cooling make them vulnerable to rupture in an aftershock from the March 11 earthquake. Japanese officials have played down that concern, and on Friday they said a sizable aftershock that struck overnight had caused no further damage at the plant.
The rift also highlights the difficulty of a debate in which both sides are forced to extrapolate possible situations with little access to crucial readings from inside the reactors.
Much of the automated measurement equipment in the reactors has been damaged, either by explosions in the early days of the crisis or by intense radiation since then. Damage to the reactors, as well as high radiation, has prevented technicians from making detailed assessments.
The Pentagon has provided airborne surveillance drones that can help monitor ground-level radiation at the plant. It is possible that American officials are basing their analysis on data they have collected independently, though Obama administration officials say they have shared their information with the Japanese.
Even so, it is not easy to explain why such different theories are being offered on fundamental questions like whether radioactive fuel from the steel reactor pressure vessel at Unit No. 2 is leaking into the bottom of the containment structure.
The Nuclear Regulatory Commission cited high levels of radiation at one spot inside the containment structure at Reactor No. 2 as evidence for its analysis. In addition, extremely high levels of radiation were detected in the water from a recently stanched leak that ran from the reactor building into a drainage ditch and into the ocean.
The Japanese flatly deny that possibility. “At this moment we do not have any data that shows there has been leakage to the containment vessels,” said Hidehiko Nishiyama, deputy director general at the Japanese regulatory agency. He also said that the Japanese and American regulators, who talk every day, were no longer so far apart on this question.
Japanese officials believe that water pumped into the reactor to cool it — as opposed to the nuclear fuel itself — might have somehow leaked out. In addition, there is evidence that an explosion may have breached the primary containment structure, which may have allowed highly radioactive water into other parts of the plant and into the ocean.
Domestic political priorities appear to be driving at least some of the reactions in both countries. In the aftermath of the 1979 accident at Three Mile Island in Pennsylvania, nuclear regulators in the United States have often planned for and talked about the worst possibilities to avoid accusations that they are lax about safety.
The pressure on American officials to give well-rounded explanations about the potential threat remains high. In fact, some members of Congress who are critics of the nuclear power industry are skeptical that the regulatory commission has been as forthcoming as it should be about the risks posed by Japan’s nuclear crisis or the potential impact on American nuclear power plants that use similar technology.
This week, Representative Edward J. Markey, Democrat of Massachusetts, an outspoken critic, engaged in a running debate with members of the commission’s staff over the conditions at Reactor No. 2 in Japan. Mr. Markey said the regulators had told his staff that fuel was leaking from the reactor, but then the commission issued a more ambiguous public statement.
“I find it rather curious that some within the Nuclear Regulatory Commission are attempting to deny the findings their own technical staff conveyed to my office as soon as it became clear that this information showed a meltdown that is more severe than some people apparently wish to acknowledge,” Mr. Markey said in a statement.
On the Japanese side, officials have an obvious desire to avoid causing panic in public statements.
“We have a very conservative culture in the nuclear industry” in the United States, said Murray E. Jennex, a professor at San Diego State University and a specialist in nuclear containment structures. “There’s nothing to gain by the N.R.C. saying things are good. At the same time, there’s nothing to gain by Tokyo Electric not downplaying stuff.”
The Americans also appear to rely more heavily on complex computer programs like Melcor that use available data to extrapolate conditions in reactors after accidents. But the regulatory commission appears to have partly relied on data provided by Tokyo Electric, something that engineers skeptical of the power company say compromises the validity of the findings.
“When the input numbers are no good, the output numbers are no good,” said Satoshi Sato, a former engineer at General Electric, which designed the reactors at Fukushima Daiichi. He argues that the conditions in the reactors are probably worse than the Japanese have reported.
The Japanese also seem to prefer presenting raw data without explaining what they think it means, said Takashi Inoue, a professor of public relations at Waseda University. Every day, Tokyo Electric, the nuclear agency, the chief cabinet secretary and others hold news conferences at which they present a blizzard of facts and numbers but rarely make broader declarations about the conditions at Fukushima Daiichi.
Industry experts are split.
Yoichi Kikuchi, a Japanese nuclear engineer who helped design the containment vessel at one of the Fukushima Daiichi reactors, agreed with the Americans that a fuel leak was possible. He said that the pressure vessel at Reactor No. 2 was especially vulnerable because of openings at the bottom where control rods are inserted. If the fuel were melting, the metal welding around those openings would easily give way, allowing the fuel to travel into the drywell, he said. The fuel could then react with the water in the suppression chamber, setting off a vapor explosion and a huge release of radiation into the air, he said.
Shuichi Iwata, a nuclear fuel expert at Tokyo University, said that he thought a leak of fuel was probably occurring, but that the consequences might not be great. “The worst case is not happening, I think,” he said.
But Toshihiro Yamamoto, an associate professor in nuclear engineering at the Kyoto University Research Reactor Institute, said the nuclear agency’s explanation was more likely. He said that it was water, not fuel, escaping from the same openings, or perhaps from a damaged circulation pump higher in the vessel.
Masashi Goto, a former Toshiba nuclear power plant designer, said that Japanese officials appeared to have decided that they gained nothing but panic from predicting outcomes. “They will never speak about the worst-case scenario,” he said. “They will never predict.”
Wednesday, April 6, 2011
Crisis at Japan Nuclear Plant Shifts to New Blast Risk
VOANews: Crisis at Japan Nuclear Plant Shifts to New Blast Risk
Workers are pumping nitrogen into one of the reactors at Japan's damaged nuclear plant in an attempt to prevent an explosion caused by dangerously overheated fuel rods.
Wednesday's crisis at the Fukushima plant came after technicians finally stopped a leak of highly radioactive water from the power station that dramatically increased the amount of radiation found in nearby ocean waters.
Chief Cabinet Secretary Yukio Edano said the water leak stopped before 6 a.m. Wednesday local time. Until then, water samples in the vicinity had shown radiation levels up to 7.5 million times the allowable limit.
However, Edano said it is too early to say with confidence that the problem has been solved, and that officials from the Tokyo Electric Power Company are trying to determine whether radioactive water is leaking from any other location.
Radioactive water dumping continues
The government official apologized to neighboring countries for Japan's failure to notify them before it began pumping thousands of tons of low-level radioactive water into the sea near the plant - an issue separate from the water leak into the ocean.
Edano said the pumping will continue, possibly until Friday, in order to drain a storage area that will be used to hold much more dangerous water - up to 200,000 times as radioactive - from inside the reactor. He said steps have been taken to ensure better communication with nearby countries before such action is taken in the future.
The chief Cabinet secretary also said authorities are considering compensation payments for fishermen affected by the disaster, as well as whether to adjust the criteria for acceptable radiation levels within the 20-kilometer evacuation zone around the reactors.
After pumping began Tuesday to transfer 11,500 tons of lightly radioactive water from the number-two reactor into the sea, South Korea protested the action as a possible violation of international law.
New threats
Officials at TEPCO, which operates the Fukushima plant, said a dangerous hydrogen buildup is taking place at its number-one reactor. Japan's NHK television quoted officials saying hydrogen is accumulating inside the reactor's containment vessel - an indication that the reactor's core has been damaged.
Hydrogen explosions destroyed the outer housings of two of the plant's six reactors during the first days of the nuclear crisis that followed the earthquake and tsunami on March 11.
And highly radioactive water has accumulated in lower levels of several reactors, following weeks in which workers pumped in massive amounts of water to prevent fuel rods from overheating. The water needs to be removed before workers can complete repairs to the permanent cooling systems.
National police said Wednesday the confirmed death toll in the March 11 disasters now stands at 12,468, with more than 15,000 people still unaccounted for.
Workers are pumping nitrogen into one of the reactors at Japan's damaged nuclear plant in an attempt to prevent an explosion caused by dangerously overheated fuel rods.
Wednesday's crisis at the Fukushima plant came after technicians finally stopped a leak of highly radioactive water from the power station that dramatically increased the amount of radiation found in nearby ocean waters.
Chief Cabinet Secretary Yukio Edano said the water leak stopped before 6 a.m. Wednesday local time. Until then, water samples in the vicinity had shown radiation levels up to 7.5 million times the allowable limit.
However, Edano said it is too early to say with confidence that the problem has been solved, and that officials from the Tokyo Electric Power Company are trying to determine whether radioactive water is leaking from any other location.
Radioactive water dumping continues
The government official apologized to neighboring countries for Japan's failure to notify them before it began pumping thousands of tons of low-level radioactive water into the sea near the plant - an issue separate from the water leak into the ocean.
Edano said the pumping will continue, possibly until Friday, in order to drain a storage area that will be used to hold much more dangerous water - up to 200,000 times as radioactive - from inside the reactor. He said steps have been taken to ensure better communication with nearby countries before such action is taken in the future.
The chief Cabinet secretary also said authorities are considering compensation payments for fishermen affected by the disaster, as well as whether to adjust the criteria for acceptable radiation levels within the 20-kilometer evacuation zone around the reactors.
After pumping began Tuesday to transfer 11,500 tons of lightly radioactive water from the number-two reactor into the sea, South Korea protested the action as a possible violation of international law.
New threats
Officials at TEPCO, which operates the Fukushima plant, said a dangerous hydrogen buildup is taking place at its number-one reactor. Japan's NHK television quoted officials saying hydrogen is accumulating inside the reactor's containment vessel - an indication that the reactor's core has been damaged.
Hydrogen explosions destroyed the outer housings of two of the plant's six reactors during the first days of the nuclear crisis that followed the earthquake and tsunami on March 11.
And highly radioactive water has accumulated in lower levels of several reactors, following weeks in which workers pumped in massive amounts of water to prevent fuel rods from overheating. The water needs to be removed before workers can complete repairs to the permanent cooling systems.
National police said Wednesday the confirmed death toll in the March 11 disasters now stands at 12,468, with more than 15,000 people still unaccounted for.
Japan reviews radiation exposure levels
UPI.com: Japan reviews radiation exposure levels
TOKYO, April 6 (UPI) -- Japan is reviewing radiation exposure levels used to designate the evacuation zone around the earthquake-damaged Fukushima nuclear power plant, officials said.
Currently, the government said outside radiation levels greater than 50 millisieverts require evacuation and levels exceeding 10 millisieverts mean residents should remain indoors, Kyodo News reported.
"The current standards represent safety in the event of absorbing a huge amount of radiation in a short period," Chief Cabinet Secretary Yukio Edano said during a news conference.
Residents within 12 miles of the Fukushima Daiichi nuclear facility damaged by the March 11 9-magnitude earthquake and tsunami are ordered to evacuate, and those living within a 12-to-18-mile radius must stay indoors.
In emergencies, the International Commission on Radiological Protection recommends the highest planned residual dose over a year's time range from 20 millisieverts to 100 millisieverts.
Seiji Shiroya, a member of the Japan's safety commission, said the international organization's recommendation would be used as a reference point to possibly strengthen Japan's radiation exposure limits.
Edano said residents who left their homes near the crippled plant should be eligible for compensation paid by plant operator Tokyo Electric Power Co., Kyodo said.
The government also decided to allow residents of areas within the zone to return home for short, supervised visits, possibly starting Monday, one month after the catastrophic quake killed thousands of people, left hundreds of thousands homeless and cut a path of destruction across northeastern Japan.
Tokyo Electric Power, operator of the Fukushima nuclear plant, said Wednesday its workers stopped the heavy leakage of highly contaminated water into the Pacific Ocean by injecting huge quantities of what is called "water glass" or sodium silicate and other chemical agents around a pit near the No. 2 reactor, believed to be the source of the leak. Water from the reactor's core, where fuel rods have partially melted, may have ended up in the pit.
Despite government assurances to the contrary, the escape of the water may have contaminated the marine environment near the plant, Kyodo News reported.
Adding to the concerns of food contamination is Tokyo Electric's program to release low-level radioactive water into the Pacific, which Tokyo Electric hoped would provide additional storage for the more contaminated water in the basement of the reactor buildings.
Japanese Industry Minister Banri Kaieda Tuesday apologized to the public, especially fishermen, for causing concern about the process but assured the discharge of the low-level radioactive water posed no major health risk. The government nuclear safety agency is part of his ministry.
Kaieda said the flooded basement of the buildings and their underground trenches at Nos. 1, 2 and 3 reactors are believed to hold about 60,000 tons of the more highly radioactive water. This water, which is also preventing workers from doing other emergency work, eventually will be removed by the company, the minister said.
As current plans stand, Tokyo Electric was to dispose of about 11,500 tons of the less contaminated water into the sea by the weekend. The more highly radioactive water is to be stored in tanks at the reactors' nuclear waste disposal sites, the nuclear safety agency said. Those tanks will be shipped by the end of the month.
But before that happens, the utility must ensure there is no more higher radioactive water leaking from the facility. Only after that can workers perform such critical tasks as restoring the cooling systems.
Agriculture, Forestry and Fisheries Minister Michihiko Kano said his ministry will tighten inspections of marine products caught off Ibaraki prefecture, down-current from the nuclear plant. He said halibut, flounder and sardines would be inspected daily for radioactive material at Nakaminato fishery port in Hitachinaka in Ibaraki prefecture, Yomiuri Shimbun reported.
The human death toll from the March 11 catastrophe, as confirmed by Japan's National Police Agency, was 12,468 as of Wednesday morning. The agency put the number of missing at 15,091.
In Fukushima Prefecture, authorities, at the request of the parents of children who are starting a new academic year, have begun taking radiation measurements in school areas. The effort will cover about 1,400 schools outside the 12.5-mile evacuation zone of the plant.
TOKYO, April 6 (UPI) -- Japan is reviewing radiation exposure levels used to designate the evacuation zone around the earthquake-damaged Fukushima nuclear power plant, officials said.
Currently, the government said outside radiation levels greater than 50 millisieverts require evacuation and levels exceeding 10 millisieverts mean residents should remain indoors, Kyodo News reported.
"The current standards represent safety in the event of absorbing a huge amount of radiation in a short period," Chief Cabinet Secretary Yukio Edano said during a news conference.
Residents within 12 miles of the Fukushima Daiichi nuclear facility damaged by the March 11 9-magnitude earthquake and tsunami are ordered to evacuate, and those living within a 12-to-18-mile radius must stay indoors.
In emergencies, the International Commission on Radiological Protection recommends the highest planned residual dose over a year's time range from 20 millisieverts to 100 millisieverts.
Seiji Shiroya, a member of the Japan's safety commission, said the international organization's recommendation would be used as a reference point to possibly strengthen Japan's radiation exposure limits.
Edano said residents who left their homes near the crippled plant should be eligible for compensation paid by plant operator Tokyo Electric Power Co., Kyodo said.
The government also decided to allow residents of areas within the zone to return home for short, supervised visits, possibly starting Monday, one month after the catastrophic quake killed thousands of people, left hundreds of thousands homeless and cut a path of destruction across northeastern Japan.
Tokyo Electric Power, operator of the Fukushima nuclear plant, said Wednesday its workers stopped the heavy leakage of highly contaminated water into the Pacific Ocean by injecting huge quantities of what is called "water glass" or sodium silicate and other chemical agents around a pit near the No. 2 reactor, believed to be the source of the leak. Water from the reactor's core, where fuel rods have partially melted, may have ended up in the pit.
Despite government assurances to the contrary, the escape of the water may have contaminated the marine environment near the plant, Kyodo News reported.
Adding to the concerns of food contamination is Tokyo Electric's program to release low-level radioactive water into the Pacific, which Tokyo Electric hoped would provide additional storage for the more contaminated water in the basement of the reactor buildings.
Japanese Industry Minister Banri Kaieda Tuesday apologized to the public, especially fishermen, for causing concern about the process but assured the discharge of the low-level radioactive water posed no major health risk. The government nuclear safety agency is part of his ministry.
Kaieda said the flooded basement of the buildings and their underground trenches at Nos. 1, 2 and 3 reactors are believed to hold about 60,000 tons of the more highly radioactive water. This water, which is also preventing workers from doing other emergency work, eventually will be removed by the company, the minister said.
As current plans stand, Tokyo Electric was to dispose of about 11,500 tons of the less contaminated water into the sea by the weekend. The more highly radioactive water is to be stored in tanks at the reactors' nuclear waste disposal sites, the nuclear safety agency said. Those tanks will be shipped by the end of the month.
But before that happens, the utility must ensure there is no more higher radioactive water leaking from the facility. Only after that can workers perform such critical tasks as restoring the cooling systems.
Agriculture, Forestry and Fisheries Minister Michihiko Kano said his ministry will tighten inspections of marine products caught off Ibaraki prefecture, down-current from the nuclear plant. He said halibut, flounder and sardines would be inspected daily for radioactive material at Nakaminato fishery port in Hitachinaka in Ibaraki prefecture, Yomiuri Shimbun reported.
The human death toll from the March 11 catastrophe, as confirmed by Japan's National Police Agency, was 12,468 as of Wednesday morning. The agency put the number of missing at 15,091.
In Fukushima Prefecture, authorities, at the request of the parents of children who are starting a new academic year, have begun taking radiation measurements in school areas. The effort will cover about 1,400 schools outside the 12.5-mile evacuation zone of the plant.
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