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Fukushima Daiichi Nuclear Power Plant Containment Vessel Water Level Continues to Drop Due to Earthquake

February 23, 2021, 5:05 PM

Tokyo Electric Power Company (TEPCO) summarized the impact of the February 13 earthquake on the Fukushima Daiichi Nuclear Power Plant on February 22, and said that the water level in the containment vessel that houses the reactor continues to drop. The Nuclear Regulation Authority (NRA) has said that water injection is continuing and that there are no safety issues at present, but has called for tighter monitoring.

At the Fukushima Daiichi Nuclear Power Plant, water is being injected to cool the melted down nuclear fuel, but the water level in the containment vessels of the Unit 1 and Unit 3 reactors has dropped by several dozen centimeters and has been on a downward trend ever since.

In addition, nitrogen has been injected into the containment vessel to prevent hydrogen explosions and increase the pressure, but in the Unit 1 reactor, the pressure gauge that measures the difference from atmospheric pressure has dropped from 1.2 kilopascals to 0.1 kilopascals and is now almost at atmospheric pressure.

The Tokyo Electric Power Company (TEPCO) says it will continue to monitor the water level and pressure, as it is possible that the earthquake may have caused damage that was created 10 years ago to spread, causing the water level and pressure to drop.

In addition to the above, it was also found that six tanks used to store water after treating contaminated water were displaced by up to 5 cm due to the earthquake.

The displacement was within the design assumptions, and no water leakage has occurred.

There was no change in the values of the monitoring posts after the quake, and there was no leakage of radioactive materials to the outside.

The Nuclear Regulation Authority (NRA), which received the report, said that cooling of the nuclear fuel and nitrogen injection are continuing and that there are no safety issues at present, and asked TEPCO to strengthen its monitoring.
https://www3.nhk.or.jp/news/html/20210223/k10012881251000.html?fbclid=IwAR0KDxC1FABC_SeNe3Sda6M55_WOvJxDE_UwBaODJls6oHlTgudC0-CHPhQ

February 25, 2021 Posted by | Fukushima 2021 | , , | Leave a comment

Water levels at Fukushima reactor containers falling after quake

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/

February 21, 2021 Posted by | Fukushima 2021 | , , , , | Leave a comment

Toxic water level at Fukushima plant still not under control

japan_fukushima_plant_with_tanks.jpeg
Highly contaminated water has accumulated in the No. 1 to No. 4 reactor buildings and turbine buildings of the Fukushima No. 1 nuclear power plant.
July 28, 2019
Almost six years after Prime Minister Shinzo Abe famously declared the contaminated water problem at the Fukushima No. 1 nuclear plant “under control,” today it remains anything but.
Tokyo Electric Power Co. (TEPCO) continues to face difficulties in dealing with water contaminated with radioactive substances at its crippled plant.
About 18,000 tons of highly contaminated water remain accumulated in reactor buildings and other places.
Abe made the declaration in September 2013 while Tokyo was bidding to win the 2020 Summer Games.
In reality, however, the situation is not under control even now.
In a meeting of the Nuclear Regulation Authority (NRA) in June, one of its members, Nobuhiko Ban, told TEPCO officials, “I want you to show whether you have a prospect (for the reduction of contaminated water) or you have given up.”
The water level did not fall as planned in an area of a basement floor at the No. 3 reactor building for two months. Asked why the level did not drop, TEPCO officials offered only vague explanations in the meeting. Ban made the remark out of irritation.
Highly contaminated water that has accumulated in reactor buildings and turbine buildings is a major concern at the Fukushima plant. In addition to water that was used to cool melted nuclear fuel at the No. 1, No. 2 and No. 3 reactors, groundwater also has flowed into those buildings through cracks.
The concentration of radioactive substances in the highly contaminated water is about 100 million times that of the contaminated water that has been processed and stored in tanks.
Immediately after the nuclear accident at the Fukushima plant in March 2011, highly contaminated water leaked into the sea through underground tunnels. As a result, radioactive substances whose concentrations were higher than allowable standards were detected in fish and other seafood.
After the nuclear accident, about 100,000 tons of water initially accumulated in the basement portions of buildings that housed the No. 1, No. 2, No. 3 and No. 4 reactors and buildings that accommodated turbines.
TEPCO has removed groundwater through wells. It also created “frozen walls” in the ground by freezing soil around the buildings. Using those methods, the company has decreased the flow of groundwater into the buildings and, as a result, the level of highly contaminated water has dropped there.
Eight years since the nuclear accident occurred, the volume of highly contaminated water in the buildings has fallen to 18,000 tons. TEPCO aims to reduce the volume further to 6,000 tons by the end of fiscal 2020.
However, work to decrease the water has not progressed as expected.
As for the area in the basement of the No. 3 reactor building, it is known that water used to cool melted nuclear fuel is flowing into the area. But why the water level does not drop only in that area is not known.
If the water level in the building remains high, highly contaminated water there could leak into the ground through cracks when the groundwater level outside the building drops. If the leaks occur, the entire effort to decrease the amount of highly contaminated water will be stalled.
The NRA is also requiring TEPCO to take anti-tsunami measures because if a huge tsunami engulfs the buildings again, it could send highly contaminated water pouring into the sea
However, anti-tsunami measures are also delayed.
The work to close openings that could become locations for leakage of highly contaminated water during a tsunami is expected to continue until the end of fiscal 2021. Such openings exist at 50 locations at present.
Additional construction of sea walls as a safeguard against another huge tsunami like the one triggered by the Great East Japan Earthquake will take time until the first half of fiscal 2020.

July 31, 2019 Posted by | fukushima 2019 | , , | Leave a comment