The temperature of unit 2′s RPV bottom rose by 11.5°C in 24 hours reaching 47.8°C at 11:00 AM on Thursday, while the temperatures from the RPV supporting skirt have also risen nearly 10°C over the last 5 days. The temperature levels from the Safety Relief Valves and the feedwater nozzles have also been steadily increasing since February 19th. Currently the temperatures levels are recorded at 50°C and 38.4°C at the feedwater nozzles. Tepco was forced to inject additional cooling water into the same reactor earlier this month after the temperature started rising at the beginning of the month.
To assess the validity of the new readings, TEPCO will again temporarily increase the volume of injected water to assess the cooling effect it may have on the readings before making any judgments on whether more gauges have failed. TEPCO has been working to transfer accumulated water from the Turbine building of Reactor 2, as water levels have increased almost 20mm in the last 12 hours. On Feburary 19th, TEPCO found that trenches around the Unit 2 water pump room were full of highly contaminated water, which was transferred to the basement of the Turbine building.
Reactor 2 is thought to be one of the main sources of leaking radioactive contamination into the ocean at Fukushima Daiichi. The high amounts of radioactivity detected in the seabed is forcing the workers to attempt a operation to cover a large swathe of seabed near the battered reactors with cement in a bid to halt the spread of radiation.
A clay-cement compound will be laid over 73,000 square metres of the floor of the Pacific in front of the Fukushima Daiichi plant on the nation’s northeast coast.The area to be covered is larger than 10 soccer fields, and will be laid over 60 centimeters thick, with 10 centimeters expected to be eaten away by seawater every 50 years.