 |
|
 |
 |
|||||||
|
| Japan allows dumping of contaminated water into sea World By LBG, GMA News The Japanese government has allowed the operator of a quake-stricken nuclear plant to dump “low-level" radiation contaminated water from its radioactive waste treatment facility to the sea, the International Atomic Energy Agency said late Monday (Manila time).IAEA said Japan’s Nuclear and Industrial Safety Agency (NISA) advised it that the Tokyo Electric Power Company was given permission to discharge 10,000 tons of low-level contaminated water. “This is in order to have sufficient capacity to store highly contaminated water found in the basement of the Unit 2 Turbine Building," the IAEA said in its update. Also, TEPCO will discharge 1,500 tons of low-level contaminated water in the sub-drain pit for Units 5 and 6 to prevent the water in the pit from leaking into the reactor buildings and potentially damaging safety-related equipment. But the IAEA said there is little risk posed to humans of the contaminated watrer. “TEPCO has estimated that the potential additional annual dose to a member of the public would be approximately 0.6 millisieverts (mSv), if they ate seaweed and seafood caught, from near the plant, every day for a year," it said. As of 7 a.m. UTC (3 p.m. in Manila), the discharge had not yet commenced even as the IAEA had asked NISA for additional information. Meanwhile, power supply to the temporary electric pumps for water supply to the Reactor Pressure Vessels (RPV) of Units 1, 2 and 3 was switched from the temporary mobile power supply to the off-site power supply on April 3. Lighting in a part of Units 1 to 4 Turbine Building was restored on April 2. Also last Saturday, transferring of water from the Unit 1 condenser storage tank to the surge tank of the suppression pool was completed in preparation for transferring water in the basement of the Unit 1 turbine building to the condenser. Transferring of water from the Unit 2 condenser to the condenser storage tank was started in preparation for transferring water in the basement of the Unit 1 turbine building to the condenser. A second US Navy barge arrived on April 2, carrying fresh water that is being transferred to the first barge which is pumping water to the “filtered water tank." TEPCO earlier identified a possible leakage path from the Turbine Building of Unit 2 to the sea via a series of trenches/tunnels used to provide power to the sea water intake pumps and supply of service water to the reactor and turbine buildings. Initial attempts on Saturday to stop the leak by pouring concrete into the pit were not successful. On Sunday, the top of the trench was broken open and polymer was poured into the trench in an attempt to stop the leakage of water to the sea through the pit, but leakage has not stopped as of 8 a.m. Monday. Fresh water injected In Unit 1, fresh water has been continuously injected into the RPV through the feed-water line at an indicated flow rate of 6 m3/h using off-site power. At Units 2 and Unit 3 fresh water is being injected continuously into the reactor pressure vessels through the fire extinguisher line indicated rates of 8 m3/h and 7 m3/h respectively using off-site power. In Unit 1 the indicated temperature at the feed water nozzle of the reactor pressure vessel (RPV) decreased from 253 °C to 243 °C and at the bottom of RPV it was stable at 113 °C. The RPV pressure indications are fluctuating and Drywell pressure is slightly increasing. The reliability of RPV pressure indications is in question. In Unit 2 the indicated temperature at the feed water nozzle of the RPV has decreased from 153 °C to 140 °C. The temperature at the bottom of RPV was not reported. Indicated Drywell pressure remains at atmospheric pressure. In Unit 3 the indicated temperature at the feed water nozzle of the RPV is stable at 114 °C and at the bottom of RPV is about 90 °C. The validity of the RPV temperature measurement at the feed water nozzle is still under investigation. Radiation monitoring Gamma dose rates are monitored in all prefectures continuously. Since March 23, reported gamma dose rates in the 45 prefectures have decreased. IAEA measurements at seven locations up to 41 km south and southwest of the Fukushima nuclear power plant showed dose rates ranged from 0.7 to 12.5 microsievert per hour. At the same locations, results of beta-gamma contamination measurements ranged from 0.1 to 2.0 megabecquerel per square metre. Since April 1, significant data related to food contamination was reported on up to 64 samples by the Japanese Ministry of Health, Labor and Welfare. “Analytical results for 133 of the 134 samples for various vegetables, spinach and other leafy vegetables, mushrooms, fruit (strawberries), various meats (beef and pork), seafood and unprocessed raw milk in twelve prefectures (Chiba, Fukushima, Gunma, Ibaraki, Kanagawa, Kyoto, Niigata, Saitama, Shizuoka, Tchigi, Tochigi and Tokyo), indicated that iodine-131, caesium-134 and/or caesium-137 were either not detected or were below the regulation values set by the Japanese authorities," IAEA said. But it said one sample of shiitake mushrooms taken on April 1 in Fukushima prefecture was above the regulation values set by the Japanese authorities for both iodine-131 and caesium-134/caesium-137. IAEA experts Two IAEA experts in BWR technology have arrived in Japan to have a direct exchange of views with the Japanese counterparts. They met with officials of NISA, TEPCO, the Japanese Atomic Energy Commission and the Nuclear Safety Commission. They will also visit the off-site emergency response center and possibly visit the Fukushima Daiichi site. A marine expert from the IAEA Environment Laboratories Monaco traveled to Japan to observe and provide advice on the collection and analysis of seawater samples. “He was embarked to the Research Vessel MIRAI on 2 April and was on board until the morning of 4 April," IAEA said. more related news
View news in other category TOP STORIES | BUSINESS | WORLD | LOCAL | SPORTS |
|||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||
|
|||||||||||||||||||||||||||
