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Sun, 2011-03-20 10:15 — mdmcdonald
Nuclear Engineering Issues

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Xenon Means Recent Fission in Reactor 2

Wed, 2011-11-02 21:55 — Kathy Gilbeaux

 

            

Graphic by The Asahi Shimbun

__________________________________________________________________________________________________

By KAZUAKI NAGATA and MIZUHO AOKI - The Japan Times - November 3, 2011

Tepco claims level in gas too small to affect shutdown effort

Tokyo Electric Power Co. said Wednesday that some of the melted fuel in reactor 2 at the Fukushima No. 1 nuclear plant may have triggered a brief criticality event.

Although the Nuclear and Industrial Safety Agency said there have been no drastic changes in the reactor's temperature and pressure level, and the reactor itself is stable overall, the discovery may mean the goal of Tepco and the government to achieve cold shutdown of all three crippled reactors by the end of the year may not be possible.

Suggesting that criticality, or a sustained nuclear chain reaction, may have occurred temporarily, or partially, Tepco said one hundred thousandth of a becquerel per cubic centimeter of xenon-133 and xenon-135 was detected in gas samples.

New Trouble Reported at Japan Nuclear Plant

Wed, 2011-11-02 00:28 — Kathy Gilbeaux

by Eric Talmadge - Associated Press (AP) - msnbc.com - November 1, 2011      

      

An aerial photo taken by a small unmanned drone and released by AIR PHOTO SERVICE, damaged Unit 3, left, and Unit 4 of the crippled Fukushima Dai-ichi nuclear power plant are seen in Okuma, Fukushima prefecture, northeastern Japan on March 24, 2011. (AP / AIR PHOTO SERVICE)

TOKYO — Officials detected a radioactive gas associated with nuclear fission at Japan's tsunami-damaged atomic power plant Wednesday, indicating there could be a new problem at one of its reactors. They injected a substance that neutralizes nuclear reactions as a precaution.

Gas from inside the reactor indicated the presence of radioactive xenon, which could be the byproduct of unexpected nuclear fission. Boric acid was being injected through a cooling pipe as a countermeasure because it can counteract nuclear reactions.

IAEA Team in Japan; Fukushima Starts Thyroid Tests

Sun, 2011-10-09 22:15 — Kathy Gilbeaux

by Eric Talmadge - Associated Press - boston.com - October 9, 2011

A boy is taken by his mother to Fukushima Medical University Hospital for a thyroid test in Fukushima, northern Japan, Sunday, Oct. 9, 2011. Local doctors began a long-term survey of children for thyroid abnormalities, a problem associated with radiation exposure. Officials hope to test some 360,000 people who were under the age of 18 when the nuclear crisis began in March, and then provide follow-ups throughout their lifetimes. Japanese on the board reads: a thyroid test entrance. (AP Photo/Kyodo News)

TOKYO—Experts from the International Atomic Energy Agency arrived in the Japanese city of Fukushima on Sunday to observe the massive decontamination effort following the world's worst nuclear disaster since Chernobyl.

Local doctors also began a long-term survey of children for thyroid abnormalities, a problem associated with radiation exposure. Officials hope to test some 360,000 people who were under the age of 18 when the nuclear crisis began in March, and then provide follow-ups throughout their lifetimes.

Cesium Fallout Map Illustrates Kanto Levels

Wed, 2011-10-05 00:11 — Kathy Gilbeaux

by Mizuho Aoki - The Japan Times - October 1, 2011

                    

The science ministry's latest aerial monitoring over Chiba and Saitama prefectures in September confirmed that radioactive cesium released from the Fukushima No. 1 power plant has contaminated parts of the Kanto region.

A ministry report released Thursday revealed that contamination was found in northern Chiba, including the cities of Kashiwa, Matsudo and Abiko, and in the mountainous areas of Chichibu in Saitama Prefecture's west and Misato in the prefecture's east.

The highest contaminated areas contained between 60,000 to 100,000 becquerels of cesium-134 and -137 per square meter, it showed. Cesium-134 has a half-life of two years and the one for -137 is 30 years.

Radiation levels in the area were between 0.2 to 0.5 microsieverts per hour, the report said.

Plutonium Traces Found in Iitate Soil

Tue, 2011-10-04 23:58 — Kathy Gilbeaux

The Japan Times - October 1, 2011

Plutonium has been detected at six locations in Fukushima Prefecture, including Iitate village around 45 km northwest of the Fukushima No. 1 nuclear plant, which suffered three reactor meltdowns after the March 11 earthquake and tsunami, science ministry officials said.

It is the first time the government has confirmed the spread of plutonium outside Tokyo Electric Power Co.'s stricken plant. The plutonium turned up in soil samples.

The detected amounts of plutonium were small and posed no danger to health, the officials said.

Plutonium has an extremely long half-life and is associated with a high risk of cancer if it enters the human body via breathing or other means.

"Because the fuels (in the reactors) melted down, plutonium may have been emitted with steam or other small particles and sent airborne," a Tepco official said. "(Judging by the amount of plutonium) it is believed to be from the accident."

The science ministry has also looked into radioactive strontium and detected the isotope at several dozen observation sites out of 100 it inspected, including a location about 80 km from the Fukushima plant.

Explosion at French Nuclear Waste Plant

Mon, 2011-09-12 16:35 — Kathy Gilbeaux

The Guardian - September 12, 2011

      

Rescue workers and medics land by helicopter at the Marcoule nuclear site, in France. Photograph: Claude Paris/AP

An explosion at a French nuclear waste processing plant that killed one person and injured four others sparked fears of a radioactive leak on Monday.

An emergency safety cordon was thrown around the Marcoule nuclear site near Nimes in the south of France immediately after a furnace used to melt nuclear waste exploded and caused a fire. It was lifted later in the day after France's nuclear safety agency, the Autorité de Sûreté Nucléaire (ASN), said there was no danger to the public.

Reports said the body of one male worker at the plant had been "found carbonised", but there was no evidence that the explosion had caused any radioactive leak, though the ASN admitted there was the "possibility of a leak of low-level radioactivity, but no shooting of radioactivity in the air". There was no information as to the cause of the explosion.

The accident came just a week after the French president, Nicolas Sarkozy, bucked the anti-nuclear trend following Japan's Fukushima disaster and pledged €1bn (£860m) of new investment in atomic power.

Microbes Generate Electricity While Cleaning Up Nuclear Waste

Wed, 2011-09-07 16:17 — Kathy Gilbeaux

Michigan State University - September 6, 2011

Homeland Security Newswire - September 7, 2011

     

MSU microbiologist Gemma Reguera (right) and her team of researchers have unraveled the mystery of how microbes generate electricity while cleaning up nuclear waste. Photo by Michael Steger.

EAST LANSING, Mich. — Researchers at Michigan State University have unraveled the mystery of how microbes generate electricity while cleaning up nuclear waste and other toxic metals.

Details of the process, which can be improved and patented, are published in the current issue of the Proceedings of the National Academy of Sciences. The implications could eventually benefit sites forever changed by nuclear contamination, said Gemma Reguera, MSU microbiologist.

“Geobacter bacteria are tiny micro-organisms that can play a major role in cleaning up polluted sites around the world,” said Reguera, who is an MSU AgBioResearch scientist. “Uranium contamination can be produced at any step in the production of nuclear fuel, and this process safely prevents its mobility and the hazard for exposure.”

NRC Task Force Review of Insights from Fukushima

Sat, 2011-08-27 23:55 — Kathy Gilbeaux

                                            

United States Nuclear Regulatory Commission - July 12, 2011

The U.S. Nuclear Regulatory Commission (NRC) has released "Recommendations for Enhancing Reactor Safety in the 21st Century: The Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident." The Near-Term Task Force was established in response to Commission direction to conduct a systematic and methodical review of NRC processes and regulations to determine whether the agency should make additional improvements to its regulatory system and to make recommendations to the Commission for its policy direction, in light of the accident at the Fukushima Dai-ichi Nuclear Power Plant.

Recommendations for Enhancing Reactor Safety in the 21st Century: The Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident (96 page .PDF report)

http://pbadupws.nrc.gov/docs/ML1118/ML111861807.pdf

http://www.nrc.gov/japan/japan-info.html

Japan Faces Costly, Unprecedented Radiation Cleanup

Fri, 2011-08-26 00:08 — Kathy Gilbeaux

by Yoko Kubota - Tokyo - Reuters - August 25, 2011

     

(Reuters) - Nearly six months after the world's worst nuclear crisis in 25 years at the Fukushima nuclear plant, Japan faces the task of cleaning up a sprawling area of radioactivity that could cost tens of billions of dollars, and thousands may not be able to return home for years, if ever.

Fuel core meltdowns at the facility in March, triggered by a huge earthquake and tsunami, released radioactive material into the air which mixed with rain and snow and covered dozens of towns as well as farmland and woods, mainly along the northeast coast of Honshu.

Tokyo has been slow to provide a plan for rehabilitation, leading some residents near the plant exposed to high levels of radioactive caesium in homes and food, have started their own cleanup instead of waiting for the government to act.

Giant Tent Being Built Over Fukushima Plant's No. 1 Reactor

Fri, 2011-08-12 16:30 — Kathy Gilbeaux

japantoday.com -August 12, 2011

                                      

In this Wednesday, Aug. 10, 2011 photo released by Tokyo Electric Power Co., building materials are being pulled up by a crane by Unit 1 reactor, seen behind the crane, to build a tent to cover the reactor at the crippled Fukushima Dai-ichi nuclear power plant in Okuma, Fukushima Prefecture, northeastern Japan. (AP / Tokyo Electric Power Co.)

TOKYO —

The operator of Japan’s damaged Fukushima Daiichi nuclear power plant is building a huge tent to cover one of the worst-hit reactors, officials said Friday.

Officials hope the cover will keep radioactive materials that have already leaked from spreading, prevent rainwater seepage and offer a barrier from possible leaks or blasts in the future.

The tent is being erected to provide a temporary replacement for the No. 1 reactor’s outer housing shell, which was destroyed in an explosion caused by high pressure the day after Japan’s deadly earthquake and tsunami on March 11.

Construction of the tent and its foundation began this week, Koji Watanabe, a spokesman for the power utility, said Friday.

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