In Unit 1 fresh water is being continuously injected into the RPV through the feed-water line at an indicated flow rate of 6 m3/h using a temporary electric pump with off-site power. In Units 2 and 3 fresh water is being continuously injected through the fire extinguisher lines at an indicated rate of 7 m3/h using temporary electric pumps with off-site power.
Nitrogen gas is being injected into the Unit 1 containment vessel to reduce the possibility of hydrogen combustion within the containment vessel. The pressure in this containment vessel has stabilised. The pressure in the RPV is increasing as indicated on one channel of instrumentation. The other channel shows RPV pressure as stable. In Units 2 and 3 Reactor Pressure Vessel and Drywell pressures remain at atmospheric pressure.
RPV temperatures remain above cold shutdown conditions in all Units, (typically less than 95oC). In Unit 1 temperature at the feed water nozzle of the RPV is 206oC and at the bottom of the RPV is 119oC. In Unit 2 the temperature at the feed water nozzle of the RPV is 167oC. In Unit 3 the temperature at the feed water nozzle of the RPV is 92oC and at the bottom of the RPV is 119oC.
On the 12th April in Units 3 and 4, fresh water (35 T and 195 T respectively) was sprayed over the Spent Fuel Pools using a Concrete Pump Truck. A sample of the water in the spent fuel pool was collected for analysis.
There has been no change in status in Unit 5 and 6 and the Common Spent Fuel Storage Facility.
2. Radiation monitoring
On 13th April, deposition of both I-131 and Cs-137 was detected in 2 and 5 prefectures respectively. For both, I-131 and Cs-137, the depositions detected were below 20 Bq/m2 at all stations.
Gamma dose rates are measured daily in all 47 prefectures. The values tend to decrease over time. For Fukushima, on 13th April a dose rate of 2.0 μSv/h was reported. In the Ibaraki prefecture, a gamma dose rate of 0.14 μSv/h was reported. The gamma dose rates in all other prefectures were below 0.1 µSv/h.
Dose rates are also reported specifically for the Eastern part of the Fukushima prefecture, for distances beyond 30 km from Fukushima-Daiichi. On 13th April, the values in this area ranged from 0.2 to 26 µSv/h.
In addition to the 7 measurements referred to in yesterday’s brief, (note- these measurements were made at distances of 25km and 33km not 32km and 62km as reported), 13 more measurements were made on 12th April at distances of 25 to 33 km, West and Northwest from the Fukushima Nuclear Power Plant by the IAEA team. At these locations, the dose rates ranged from 0.5 to 16.5µSv/h. At the same locations, results of beta-gamma contamination measurements ranged from 0.05 to 2.1 Megabecquerel/m2.