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Air duct corrosion and holes found at seven nuclear plants

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Corrosion is seen in a ventilation duct at the No. 3 unit of the Kashiwazaki-Kariwa nuclear power plant in Niigata Prefecture. | NUCLEAR REGULATION AUTHORITY
 
Corrosion and holes have been found in ventilation ducts at 12 reactors at seven nuclear plants across the country, the Nuclear Regulation Authority said Wednesday, raising concerns that workers could be exposed to radiation in the event of an accident.
The governmental nuclear watchdog released the results of a nationwide survey it had ordered following a revelation in December 2016 that corrosion had left multiple holes in the air ducts of the No. 2 reactor at Chugoku Electric Power Co.’s Shimane plant in western Japan. That reactor was not included in the survey.
Serious corrosion was found at the No. 3 unit of the Kashiwazaki-Kariwa plant in Niigata Prefecture operated by Tokyo Electric Power Company Holdings Inc. and may have abnormally affected ventilation of the central control room, the watchdog said.
Although the No. 7 unit at the same plant has passed a test to resume operation, the NRA said it will inspect the impact of any corrosion found at the reactor. No abnormality associated with corrosion has been found at the remaining 10 units, it said.
Corrosion or holes were found in steel or galvanized steel ducts at Tohoku Electric Power Co.’s Onagawa nuclear plant, Japan Atomic Power Co.’s Tokai No. 2 nuclear plant, Tepco’s Fukushima No. 1 nuclear plant and Kashiwazaki-Kariwa nuclear plant, Chubu Electric Power Co.’s Hamaoka plant, Hokuriku Electric Power Co.’s Shiga nuclear plant and Chugoku Electric’s Shimane plant.
If an accident occurs, radioactive materials could flow into a plant’s central control room through such holes, putting workers in danger of radiation exposure.
At the No. 3 reactor at the Kashiwazaki-Kariwa plant, a crack as large as 13 centimeters in length and 5 cm in width was found. A total of nine holes and cracks have been discovered at the Nos. 3 and 7 units at the plant.
All the reactors with corrosion were boiling-water reactors, the same type used at the Fukushima No. 1 plant, which spewed a massive amount of radioactive material into the atmosphere following the March 2011 earthquake and tsunami.
No problems have been detected at pressurized-water nuclear reactors, as filtering and other measures take place near air inlets.
The holes at the No. 2 unit at the Shimane plant were discovered when insulation materials covering the ducts were removed for inspection.
The holes, the largest of which measured about 100 centimeters wide and about 30 centimeters long, are believed to have been caused by dew condensation and rainwater that seeped inside the building, as well as salt deposits on the ducts, given that the corrosion extended about 50 meters from the air inlet and spread from the inner surface of the ducts.
Chugoku Electric has decided to increase the number of inspection points at sections near fresh-air inlets and bolster anti-corrosion measures, including the installation of a dehumidifier.
https://www.japantimes.co.jp/news/2018/05/23/national/air-duct-corrosion-holes-found-seven-nuclear-plants/#.WwVWzJyRU0M
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May 24, 2018 Posted by | Japan | , , | Leave a comment

Anomalies in wildlife and the ecosystem around Chernobyl and Fukushima

 

Dr. Timothy Mousseau, Professor of Biological Sciences, University of South Carolina. Mousseau discussed his many studies on the health impacts on wildlife and biota around Chernobyl and Fukushima which soundly debunk the notion that animals there are “thriving.”

April 9, 2017 Posted by | radiation | , , , , , | Leave a comment

Japanese steel in French nuclear facilities found to have high impurity level

The concentration of impurity in steel a Japanese manufacturer supplied to nuclear facilities in France exceeded the standards set by the European country, Japan’s nuclear watchdog said Wednesday, meaning the steel could be weaker than expected.

Briefed recently by French regulators about the finding, the Nuclear Regulation Authority is looking into allegations regarding the products provided by the Kitakyushu-based firm under scrutiny, Japan Casting & Forging Corp.

The NRA said it needs to carry out tests to evaluate whether the steel is in fact lacking in strength.

The French regulators said in June they found steel containing larger-than-expected amounts of impure substances in facilities such as reactor pressure vessels at 18 reactors operating in France and are investigating the matter. The steel products in question were made by Japan Casting & Forging and Creusot Forge, a subsidiary of France’s Areva SA.

In August, the NRA ordered local utilities hosting nuclear power plants in Japan to examine reactors and other major parts at the plants. The utilities have been asked to report the results to the NRA by the end of October.

Japan Casting & Forging is also under scrutiny in Japan as it is responsible for the construction of reactor pressure vessels in 13 Japanese nuclear reactors including the Sendai Nos. 1 and 2 reactors operated by Kyushu Electric Power Co. in Kagoshima Prefecture.

Currently, the two Sendai reactors are operating in Japan after passing stricter safety checks in the wake of the 2011 nuclear crisis that crippled the Fukushima No. 1 nuclear power plant in Fukushima Prefecture.

Japan Casting & Forging had said earlier it has removed the impurities from its steel as instructed by its clients.

The NRA said the standard for carbon content in metals — a gauge of impurity — is below 0.22 percent in France, while the figure in Japan is below 0.25 percent.

But in some products provided by the Japanese firm in some nuclear facilities, carbon content in steel was over 0.3 percent.

http://www.japantimes.co.jp/news/2016/09/14/national/japanese-steel-french-nuclear-facilities-found-high-impurity-level/#.V9l5QTX8-M8

September 14, 2016 Posted by | Japan | , , | Leave a comment

JCFC steel in troubled French reactor also used in 13 Japanese nuclear power plants

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Thirteen Japanese nuclear reactors were constructed with steel made by the same domestic company that produced material used in a French power plant that has come under scrutiny after anomalies were found in the structure of its reactor vessel.

Six utilities used steel from Japan Casting & Forging Corp. (JCFC), they all said in separate statements Friday. The company was identified by Japanese authorities last month as having supplied steel to the Flamanville nuclear plant, developed by Electricite de France SA and Areva SA, where the French safety authority last year found weaker-than-expected steel.

The Nuclear Regulation Authority asked utilities last month to examine reactor parts made by the same companies that supplied the Flamanville facility. Utilities must now evaluate whether their reactor pressure vessels meet national standards and report the results to the regulator by Oct. 31.

“It’s just to be sure,” said an NRA official.

JCFC said it has thrown away steel parts that lead to weaker products, adding that its steels have cleared the safety criteria.

The Japanese facilities affected include Kyushu Electric Power Co.’s Sendai No. 1 and 2 reactors in Kagoshima Prefecture, the company said Friday. The plant was restarted last year and is facing opposition from a new governor who has demanded they be temporarily shut for inspections.

Reactors now in operation don’t need to be shut down, Yoko Kobayashi, an official with the NRA’s planning division, said Friday. The affected utilities are now required to submit manufacturing reports and past evaluation results, she said.

The steel scrutiny is the latest hurdle for the nuclear power industry since the 2011 Fukushima disaster and could hamper the government’s goal of having it account for as much as 22 percent of its energy mix by 2030.

Local court challenges have threatened reactor operations, and even those restarted under new post-Fukushima safety rules have faced a rocky road. Only three of the nation’s 42 operable reactors are online.

Parts made by JCFC met rigorous standards requested by the utilities, and the company will provide support going forward, JCFC official Seigo Otsubo said Friday.

EDF and Areva are conducting additional tests to determine whether the anomalies present a safety issue. The two companies said in April that the submission of their report to French regulators about the Flamanville reactor has been delayed until year-end.

EDF has also determined that steam generator channel heads at 18 French reactors contain anomalies similar to those at Flamanville, Autorite de Surete Nucleaire, the safety regulator, said in June.

According to statements from the utilities, the domestic reactors made with steel from JCFC include: units 2 and 4 at the Fukushima No. 2 power plant run by Tokyo Electric Power Co. Holdings Inc.; unit 2 at the Takahama power plant and units 1 and 2 at the Oi power plant, both run by Kansai Electric Power Co.; reactors 2, 3 and 4 at the Genkai plant and reactors 1 and 2 at the Sendai plant run by Kyushu Electric Power Co.; reactor 2 at the Ikata plant run by Shikoku Electric Power Co.; reactor 1 at the Shika plant managed by Hokuriku Electric Power Co.; and reactor 2 at the aging Tsuruga plant run by the Japan Atomic Energy Agency.

http://www.japantimes.co.jp/news/2016/09/04/national/jcfc-steel-troubled-french-reactor-also-used-13-japanese-nuclear-power-plants/#.V8x3Fa3KO-c

September 5, 2016 Posted by | Japan | , , | Leave a comment

Steel in Troubled French Nuclear Reactor Used in 13 Japanese Reactors

Thirteen Japanese nuclear reactors were constructed with steel from the same company used in a French power plant that’s under scrutiny for anomalies found in the reactor vessel’s structure.

Six utilities used steel from Japan Casting & Forging Corp., they all said in separate statements on Friday. The steelmaker was identified by Japanese authorities last month as supplying steel to the Flamanville nuclear plant, developed by Electricite de France SA and Areva SA, where the French safety authority last year found weaker-than-expected steel.

Japan’s nuclear regulators asked utilities last month to examine reactor parts manufactured by the same companies as the Flamanville facility. Utilities must now evaluate whether their reactor pressure vessels meet Japan’s standards and report the results to the Nuclear Regulation Authority by Oct. 31.

The Japanese facilities affected include Kyushu Electric Power Co.’s Sendai No. 1 and 2 reactors, the company said Friday. The plant was restarted last year and is facing opposition from the region’s new governor, who has demanded they be temporarily shut for inspections.

Reactors that are currently operating don’t need to be shut down, Yoko Kobayashi, an official with the NRA’s planning division, said Friday. The affected utilities are now required to submit manufacturing reports and past evaluation results, she said.

Nuclear Challenge

The steel scrutiny is latest hurdle for nuclear power in Japan and the government’s goal of having it account for as much as 22 percent of its energy mix by 2030 in the wake of the 2011 Fukushima disaster. Local court challenges have threatened reactor operations, and even those restarted under new post-Fukushima safety rules have faced a rocky road. Only three of the nation’s 42 operable reactors are online.

Parts manufactured by JCFC met rigorous standards requested by the utilities, and the company will provide support going forward, Seigo Otsubo, an official at the company, said Friday.

EDF and Areva are conducting additional tests to determine whether the anomalies are a safety issue. The two companies said in April that the submission of their report to French regulators about the Flamanville reactor has been delayed until year-end.

EDF has also determined that steam generator channel heads at 18 French reactors contain anomalies similar to those at Flamanville, Autorite de Surete Nucleaire, the safety regulator, said in June.

Japanese reactors that used steel from JCFC, according to statements from the companies:

http://www.bloomberg.com/news/articles/2016-09-02/steel-in-troubled-french-nuclear-reactor-used-in-japanese-plants

September 3, 2016 Posted by | Japan | , , | Leave a comment