A Tepco employee wearing a protective suit and mask gives lectures in front of No. 3 reactor building at the tsunami-crippled Fukushima No. 1 nuclear power plant in Okuma, Fukushima Prefecture, in February 2019.
February 20, 2021
Tokyo Electric Power Co. Holdings Inc. has said that the water levels in the containment vessels for the No. 1 and No. 3 reactors at its disaster-crippled Fukushima No. 1 nuclear power plant have fallen by tens of centimeters.
The water levels are continuing to drop by several centimeters each day, Tepco said Friday.
The event has had no radiation impact outside of the plant’s premises, the company said, noting that the injection of water into the reactors, as well as operations to cool melted nuclear fuel debris at the bottom of the containment vessels, are continuing.
The plant was heavily damaged in the powerful March 2011 earthquake and tsunami.
On Feb. 13, an earthquake measuring a strong 6 — the second-highest level on the Japanese seismic intensity scale — rocked the Tohoku region, which includes Fukushima Prefecture. Existing damage to piping and other parts of the containment vessels may have expanded as a result of the temblor, Tepco officials said.
The utility is continuing to pump 3 tons of water per hour into the reactor containers to cool the fuel debris.
While water continues leaking to the reactor buildings through the damaged areas of the containment vessels, the water levels in the No. 1 and No. 3 reactor containers had been kept at some 1.9 meters and 6.3 meters from the bottom, respectively, before Saturday’s earthquake.
According to the officials, workers detected a fall in the water level in the No. 1 reactor container around 11 p.m. Thursday.
The water level is seen to have dropped by 40-70 centimeters in the No. 1 reactor container and by some 30 centimeters in the No. 3 reactor container, the officials said.
Drops in the water levels are believed to have started around Monday in the No. 1 reactor vessel and around Sunday in the No. 3 reactor vessel, they said.
The sizes of the falls in the water levels are almost the same as those observed during an experiment conducted last year to suspend water injection, the officials said.
The company will take measures, such as increasing water injection, as needed while continuing to monitor the water levels, the officials said.
Ramping up water injection will lead to an increase in the amount of radioactive water, possibly affecting the quantity of water that is kept in tanks at the premises of the nuclear power station after being treated to remove some radioactive substances.https://www.japantimes.co.jp/news/2021/02/20/national/fukushima-water-leak-earthquake/