Fukushima 1 Nuclear Accident Day 6: Wednesday, 16 March

05:45
A location in the building of reactor 4 has been reported to be on fire at the Fukushima I (by NHK TV). According to one of the worker's testimony, flames were present at the location of Tuesday's fire. The fire was verified by satellite imagery showing smoke rising from the reactor 4 building. The fire disappeared later. IAEA confirms reports that a fire was visually observed in unit 4, in a similar area as the original fire. This new fire cast into doubt the earlier hope that the Tuesday blaze in the Unit 4 housing was caused by lubricating oil pumps; instead TEPCO officials acknowledge it is possible the spent fuel rods are uncovered and overheating, remarking that "the possibility of a re-criticality is not zero." Iouli Andreev, former director of the Soviet Spetsatom clean-up agency involved in Chernobyl clean-up, as well as Laurence Williams, professor of nuclear safety at the University of Central Lancashire, speculate that the Fukushima management had engaged in an unsafe practice of re-racking spent rods in the pool well beyond its rated capacity, in effect heightening danger of melting and pool boil-off.
06:15
IAEA Reports that the fire previously observed in unit 4 is no longer visible.
07:30
Evacuation of the 20km zone around Fukushima I has been completed.
08:00 (approximately)
The US Embassy in Japan is recommending that all personnel to adhere to the Japanese safety measures, "including their recommended 20 km radius for evacuation and additional shelter-in-place recommendations out to 30 km."
08:00
Status of the Fukushima I station at 08:00 March 16

Unit 1 Unit 2 Unit 3 Unit 4 Unit 5 Unit 6
Power output (MWe) 460 784 784 784 784 1100
Type of reactor BWR-3 BWR-4 BWR-4 BWR-4 BWR-4 BWR-5
Status at earthquake In service In service In service Defueled Outage (scheduled) Outage (scheduled)
Fuel integrity 70% damaged 33% damaged Damaged Not damaged Not damaged Not damaged
Containment integrity Not damaged Damage suspected Not damaged Not damaged Not damaged Not damaged
Core cooling system 1 (ECCS/RHR) Not functional Not functional Not functional Not necessary Not necessary Not necessary
Core cooling system 2 (RCIC/MUWC) Not functional Not functional Not functional Not necessary Not necessary Not necessary
Building integrity Severely damaged Slightly damaged Severely damaged Partially damaged Not damaged Not damaged
Pressure vessel, water level Around half of the fuel Recovering after dried-up Around half of the fuel Safe Safe Safe
Pressure vessel, pressure Stable Fluctuating Stable Safe Safe Safe
Containment pressure Stable D/W: Unknown, S/P: Atmosphere Stable Safe Safe Safe
Seawater injection into core Continuing Continuing Continuing Not necessary Not necessary Not necessary
Seawater injection into containment building Continuing To be decided To be decided Not necessary Not necessary Not necessary
Containment venting Continuing Preparing Continuing Not necessary Not necessary Not necessary
Spent fuel integrity (no data) (no data) (no data) SFP level low SFP level decreasing SFP level decreasing
Environmental effect (NPS border and onsite) 6308 μSv/hour at 23:35, March 15, with increases to 1,000 mSv/hour early March 16 and then decreasing to 800–600 mSv/hour
Evacuation radius 20 km
INES Level 4 (estimated by NISA); Level 6 (estimated by France's Nuclear Safety Authority, ASN)
08:30
White smoke was seen rising from the vicinity of Fukushima I Unit 3. Damage to the containment vessel of the unit was suspected. Later TEPCO reported that failing to cool the Spent Fuel Pool resulted in evaporation of pool water, which caused steam.
09:00
The fire that broke out inside the building of Fukushima I reactor 4 appears to be extinguished. According to Kyodo News, TEPCO is considering spraying boric acid by helicopter to prevent the spent nuclear fuel rods from reaching criticality again and starting a nuclear chain reaction. However, TEPCO said that readings showed high levels of radiation, making the building inaccessible, and therefore making the spraying "extremely difficult".
10:01 (estimated)
Reactor 3 at Fukushima I nuclear power plant begins emitting white smoke.
10:46
TEPCO says the reactor 3 at Fukushima I nuclear power plant has been emitting white smoke for about 45 minutes.
11:00
Radiation reading at the Fukushima I Nuclear Power Station (NPS) border is 3391 µSv/hour
11:36
The remaining 50 workers located in the Fukushima I nuclear power plant have evacuated after radiation levels there have surged.
11:40
Chief cabinet secretary Edano announces that the white fumes emerging from the plant may constitute radioactive steam that has breached Fukushima I Unit 3's containment.
12:30
Status of the Fukushima I station at 12:30 March 16

Unit 1 Unit 2 Unit 3 Unit 4 Unit 5 Unit 6
Power output (MWe) 460 784 784 784 784 1100
Type of reactor BWR-3 BWR-4 BWR-4 BWR-4 BWR-4 BWR-5
Status at earthquake In service In service In service Defueled Outage (scheduled) Outage (scheduled)
Fuel integrity 70% damaged 33% damaged Damaged Not damaged Not damaged Not damaged
Containment integrity Not damaged Damage suspected Damage suspected Not damaged Not damaged Not damaged
Core cooling system 1 (ECCS/RHR) Not functional Not functional Not functional Not necessary Not necessary Not necessary
Core cooling system 2 (RCIC/MUWC) Not functional Not functional Not functional Not necessary Not necessary Not necessary
Building integrity Severely damaged Slightly damaged Severely damaged Severely damaged Not damaged Not damaged
Pressure vessel, water level Around half of the fuel Recovering after dried-up Around half of the fuel Safe Safe Safe
Pressure vessel, pressure Stable Fluctuating Stable Safe Safe Safe
Containment pressure Stable D/W: Unknown, S/P: Atmosphere Stable Safe Safe Safe
Seawater injection into core Continuing Continuing Continuing Not necessary Not necessary Not necessary
Seawater injection into containment building Continuing To be decided To be decided Not necessary Not necessary Not necessary
Containment venting Continuing Preparing Continuing Not necessary Not necessary Not necessary
Spent fuel integrity (no data) (no data) High temperature suspected SFP level low,
Preparing water injection,
Damage to fuel rods suspected		 SFP temperature increasing SFP temperature increasing
Environmental effect (NPS border) 3391 µSv/hour at 11:00, March 16
Evacuation radius 20 km from Nuclear Power Station (NPS)
INES Level 4 (estimated by Japanese NISA and accepted by the international IAEA); Level 6 (estimated by the French Nuclear Safety Authority, ASN and the Finnish nuclear authorities)
12:35 (approximate)
The 50 personnel that were evacuated at 1136 returned to the facility after radiation levels subsided.
14:30
Radiation reading at the Fukushima I Nuclear Power Station (NPS) border is 1937 µSv/hour.
17:26
TEPCO says that work on cooling the Fukushima I reactors is suspended due to radiation risks for the second time.
18:00
Radiation decreased to 1500 µSv/hour at Fukushima I site boundary (NHK TV). See also this map of various detectors stationed around Japan (owned by public and government).
19:00
The Fukushima I Unit 3 Spent Fuel Pool level is low, with preparations for water injection.
19:00
Status of Fukushima I at 19:00 March 16

Unit 1 Unit 2 Unit 3 Unit 4 Unit 5 Unit 6
Power output (MWe) 460 784 784 784 784 1100
Type of reactor BWR-3 BWR-4 BWR-4 BWR-4 BWR-4 BWR-5
Status at earthquake In service In service In service Defueled Outage (scheduled) Outage (scheduled)
Fuel integrity 70% damaged 33% damaged Damaged No fuel rods Not damaged Not damaged
Containment integrity Not damaged Damage suspected Damage suspected Not damaged Not damaged Not damaged
Core cooling system 1 (ECCS/RHR) Not functional Not functional Not functional Not necessary Not necessary Not necessary
Core cooling system 2 (RCIC/MUWC) Not functional Not functional Not functional Not necessary Not necessary Not necessary
Building integrity Severely damaged Slightly damaged Severely damaged Severely damaged Not damaged Not damaged
Pressure vessel, water level Around half of the fuel Recovering after dried-up Around half of the fuel Safe Safe Safe
Pressure vessel, pressure Stable Fluctuating Stable Safe Safe Safe
Containment pressure Stable D/W: Unknown, S/P: Atmosphere Stable Safe Safe Safe
Seawater injection into core Continuing Continuing Continuing Not necessary Not necessary Not necessary
Seawater injection into containment building Continuing To be decided To be decided Not necessary Not necessary Not necessary
Containment venting Continuing Preparing Continuing Not necessary Not necessary Not necessary
Integrity of fuel in Spent Fuel Pool (SFP) (no data) (no data) SFP level low,
Preparing water injection		 SFP level low,
Preparing water injection,
Damage to fuel rods suspected		 SFP temperature increasing SFP temperature increasing
Environmental effect (NPS border) 1937 µSv/hour at 14:30, March 16
Evacuation radius 20 km from Nuclear Power Station (NPS). People who live between 20km to 30km from the Fukushima I Nuclear Power Station are to stay indoors.
INES Level 4 (estimated by Japanese NISA and accepted by the international IAEA); Level 6 (estimated by the French Nuclear Safety Authority, ASN and the Finnish nuclear authorities)
19:50
Radiation level at Fukushima II reactor (10km south of Fukushima I): 28.6 µSv/hour. ref
21:05
Australian Foreign Minister Kevin Rudd advises Australians to leave Tokyo.
23:30
130 additional people are allowed in the plant as radiation levels fall.
23:55
IAEA Web Site Reports that "Japanese authorities have reported concerns about the condition of the spent nuclear fuel pool at Fukushima I Unit 3 and Unit 4. Japanese Defense Minister Toshimi Kitazawa announced Wednesday that Special Defence Forces helicopters planned to drop water onto Unit 3, and officials are also preparing to spray water into Unit 4 from ground positions, and possibly later into Unit 3. Some debris on the ground from the 14 March explosion at Unit 3 may need to be removed before the spraying can begin."

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