Japan is about to usher in the 10th anniversary of the “March 11” earthquake and tsunami. An investigation report shows that the radiation of many damaged reactor buildings at Fukushima Daiichi nuclear power plant is extremely strong, which makes it more difficult to remove spent fuel rods (used nuclear fuel rods) from the reactor, which may further delay the scrapping operation of Fukushima Daiichi nuclear power plant.
An investigation team of Japan’s atomic force Regulatory Commission released the report on the 26th, Tokyo news reported on the 27th. The concrete containment top cover of the reactor pressure vessel of Fukushima unit 1 was displaced and dropped during the hydrogen explosion, while the top covers of units 2 and 3 remained in place. The roofs are made of three layers of reinforced concrete, each about 12 meters in diameter and weighing about 465 tons.
According to the investigation report, the activity of radioactive cesium attached to the containment cover of unit 1 is estimated to be 100-200 trillion Becquerels, that of unit 2 is estimated to be 200-400 billion Becquerels, and that of unit 3 is estimated to be 300 billion Becquerels.
According to Kyodo news agency, when the Fukushima nuclear accident occurred, the radioactivity in units 1 to 3 was estimated to be 700000 billion Becquerels. This means about one tenth of the radiation remains on the reactor containment head.
The amount of radiation near the containment cover is equally alarming. Among them, the maximum radiation value of unit 2 building is up to 10 sieverts per hour. People who are exposed to radiation of this intensity will die in about an hour.
The Japanese government and Tokyo Electric Power Company are promoting the scrapping operation of the Fukushima nuclear power plant, and the removal of spent fuel rods is regarded as the “most difficult problem”. Among the four units, the unit 4 with less damage had all taken out the spent fuel rods in December 2014. According to the scrapping schedule set by the Japanese government and TEPCO, all spent fuel rods should be removed in 2031 and scrapped from 2041 to 2051.
The latest investigation results undoubtedly make it more difficult to remove the spent fuel rods, which means that it is difficult to remove the spent fuel rods by opening the containment. “Tokyo news” interpretation, the Japanese government and TEPCO will have to modify the scrap schedule.
On March 11, 2011, a magnitude 9.0 Earthquake Occurred in the Northeast sea area of Japan and triggered a tsunami, resulting in the power outage of Fukushima nuclear power plant, the core meltdown of three units in succession, and a large amount of radiation leakage.
The investigation team of the atomic force Regulatory Commission is responsible for analyzing the Fukushima nuclear accident, and released the investigation results in October 2014. The latest report summarizes the findings after September 2019, covering 326 pages. (Liu Xiuling) (special feature of Xinhua News Agency)