Come for the Politics, Stay for the Pathologies

Thursday, March 17, 2011

Fukushima Nuclear Accident: Update Link



Japan’s NHK broadcasting network reported that Tokyo Electric Power Co. confirmed that the March 11 earthquake and tsunami were beyond the Fukushima Daiichi plant’s design standards.
TEPCO believes the tsunami that inundated the Fukushima Daiichi site was 14 meters high, the network said. The design basis tsunami for the site was 5.7 meters, and the reactors and backup power sources were located 10 to 13 meters above sea level. The company reported that the maximum earthquake for which the Fukushima Daiichi plants were designed was magnitude 8. The quake that struck March 11 was magnitude 9.
Smoke seen from Fukushima Daiichi reactor 3 on Monday subsided after about two hours. Water pressure and levels at the reactor were unchanged through the episode, as were radiation levels, the company said.
The site was temporarily cleared of workers after smoke rose from at the secondary containment buildings that house reactors 2 and 3. The Nuclear and Industrial Safety Agency said the smoke from reactor 2 caused radiation levels downwind to rise for about three and a half hours.
TEPCO continues work to reconnect external power to all six reactors. Connections were made to the distribution line at reactor 1 and 2, and components and circuits at those reactors are being checked. Similar power connections have been made to reactors 5 and 6 and a diesel generator is providing power to a cooling pump for the used fuel pools. Power cable is being laid to reactor 4, and power is expected to be restored to reactors 3 and 4 by Tuesday.
Japan’s Chief Cabinet Secretary Yukio Edano announced that Prime Minister Kan has ordered the governors of four prefectures near Fukushima to restrict the shipment of spinach and “kakina,” another leafy vegetable. The shipment of milk from Fukushima prefectures was also restricted. Edano said the order was a precautionary emergency measure.

Fukushima Daiichi
Tokyo Electric Power Co. continued efforts on Monday to restore power to its reactors at Fukushima Daiichi as well as stabilize cooling in the used fuel pools of some reactors. Reactors 1, 2 and 3 are in stable condition and reactors 5 and 6 are stable and being cooled by systems powered by electricity that was restored over the weekend.
The Tokyo Fire Department sprayed cooling water into the reactor 3 used fuel pool for about 4.5 hours, ending early Monday morning. At reactor 4, Japan’s Self-Defense Force sprayed water into the pool for about two hours. Overall, 13 fire engines have been used in the spraying. Efforts to spray water into the used fuel pools at reactors 3 and 4 reactor buildings and used fuel pools was stopped on Monday while TEPCO assessed the effectiveness of these efforts.
Workers were evacuated from the area around reactors 2 and 3 Monday when smoke was observed coming from the secondary containment buildings.
Electricity is expected to be restored to both reactors 3 and 4 by March 23.
Radiation dose rates at monitoring posts are slightly higher than on past days. Rates at the plant site boundary range from 1 to 3 millirem per hour. Radiation dose rates in the area where fire trucks have been located are reported to be 2 to 3 rem per hour, with some isolated areas as high as 30 rem per hour.
Fukushima Daini
All reactors are in cold shutdown and are stable

Fukushima Daiichi
Reactors 5 and 6 at the Fukushima Daiichi nuclear power plant are in cold shutdown, the International Atomic Energy Agency reports. This means that the reactors are in a safe mode, with cooling systems stable and under control, and with low temperatures and pressures.
When the quake struck, both reactors had been shut down for inspection and refueling, and had some fuel inside the reactor cores. Tokyo Electric Power Co. has been using a pair of diesel generators at reactor 6 to pump water through the reactors and to their used fuel pools.
An elite firefighting unit sprayed water over the spent fuel pool of reactor 3, Japan's Nuclear and Industrial Safety Agency reported.
Japan's NISA reported that TEPCO early this morning began pumping sea water into the used fuel pool at reactor 2.
The company is checking individual circuits as it prepares to restore offsite electricity to the reactor's main control room, where it will be able to check and monitor plant systems. To restore power to reactors 3 and 4, TEPCO is considering laying power cables to bypass a radiation contaminated area.
The March 11 earthquake was stronger than the Daiichi plant was designed to withstand, the Japan Atomic Industrial Forum reported. Maximum ground acceleration near reactor 3 was 507 centimeters per second squared - more than the plant's design reference values of 449.
Fukushima Daini
All four reactors at Fukushima Daini nuclear power plant are in cold shutdown with normal cooling.

At a March 19 news conference, Japan’s Chief Cabinet Secretary Yukio Edano said that sea water injection is continuing at reactors 1, 2 and 3 at the Fukushima Daiichi nuclear power plant.
Preparations were being made to spray water into the used fuel pool at reactor 4, and an unmanned vehicle sprayed more than 1,500 gallons of water over seven hours into the used fuel pool at reactor 3, Edano said. He also said he believed that the situation at the reactor 3 fuel pool is stabilizing.
Some reactor cooling capacity has been restored at reactors 5 and 6 after the installation of generators at those reactors, Edano added.
Edano said that progress had been made on “a fundamental solution” to restore power at the Fukushima Daiichi nuclear power plant, with electricity expected to be restored at reactors 1 and 2 today and reactor 3 as early as Sunday.
Edano said that additional equipment was being transported to the site and that other means of providing cooling water to the pool is be examined.
Radiation dose at the west gate of the Fukushima Daiichi was 83 millirem per hour on March 18 at 7:10 p.m. EDT and dropped to 36 millirem per hour by 8 p.m. EDT, Edano said. Radiation levels have decreased since March 16. Although they are higher than normal, radiation levels near the reactors are within the range that allows workers to continue onsite recovery measures, the International Atomic Energy Agency said.
According to the IAEA, radiation dose rates in Tokyo and other areas outside the 30-kilometer zone remain far below levels which would require any protective action by the public.
All reactors at the Fukushima Daini nuclear power plant are in cold shutdown (See the Japan Atomic Industrial Forum website).
Radiation levels have increased above the federal government’s level in some food products from the Fukushima Prefecture and nearby areas. These levels were detected in samples of milk in Fukushima Prefecture and six samples of spinach in neighboring Ibaraki Prefecture, according to the Japan Atomic Industrial Forum. Edano said that if these products are consumed for a year, the total radiation dose would be equivalent to one CT scan.
Additional monitoring of food products is continuing in those regions.

Not “up to the minute” but very informative. From The Captain’s Journal:

"The cores for Units 1, 2 and 3 are already damaged.  They are partially melted, and partially shattered and rubblized, sitting in the lower part of the reactor vessel.  Most of the radiological source term that can be expected to be released from the core to containment
has already been released. It is being held up inside hard
containments and depleted via radioactive decay, plateout, etc.

The work now has to do with mitigation of the radiological source terms, from water injection into the reactor coolant system, water washdown of plant components, and so on. If the semi-volatile fission products and alkali metals are in effluent, they will likely not re-evolve to the atmosphere in large quantitie(s). Most importantly, for now, the Spent Fuel Pools deserve attention, and hopefully the operators will be able to mitigate zirconium fire events in the pools.

The Japanese are performing heroically, and the main stream media will catch up in several days (or weeks). The current efforts are focused on radiological source term and thus dose mitigation, not the prevention of core melt events."

h/t Hershel Smith


Reactors 1, 2 and 3 at the Fukushima Daiichi nuclear power plant are in stable condition, with workers continuing to provide seawater cooling into the reactors. Containment integrity is believed to be intact on reactors 1, 2 and 3, and containment building pressures are elevated but are within design limits.

Site radiation doses have been decreasing since March 16. Radiation dose rates are fluctuating based on some of the relief operations, such as adding cooling water to the used fuel pools. Recent readings at the plant boundary are about 2 millirem per hour. Radiation dose rates at reactor 3 range between 2,500 and 5,000 millirem per hour.

The Japanese Self-Defense Force restarted cooling water spray into the Unit 3 reactor building and spent fuel pool at around 1 a.m. EDT on March 18. Plans are to spray 50 tons of water on the reactor 3 reactor building/spent fuel pool using seven fire-fighting trucks.

A diesel generator is supplying power to reactors 5 and 6. TEPCO is installing high voltage cables from a nearby transmission line to reactors 1 and 2. Once electricity supply is re-established, priority will be given to restoring power to reactor heat removal systems and cooling water pumps. Workers are seeking to install electrical cables to reactors 3 and 4 components in about two days.

Fukushima Daini

All four reactors at Fukushima Daini remain shut down with normal cooling being maintained using residual heat removal systems.

Daiichi Accident Rated 5 on International Event Scale

New International Nuclear and Radiological Event Scale (INES) ratings have been issued for the accident at the Fukushima Daiichi and Daini nuclear power plants, the International Atomic Energy Agency said.

Reactor core damage at the Daiichi reactors 2 and 3 caused by a loss of cooling function has resulted in a rating of 5 on the seven-point scale.

The loss of cooling and water supply functions in the spent fuel pool of reactor 4 was rated a 3, or “serious” incident. The loss of cooling functions in the reactors 1, 2 and 4 of the Fukushima Daini nuclear power plant has led to a rating of 3.

The rating for the Chernobyl accident was 7, or a “major accident” on the INES scale. The Three Mile Island accident was 5, or an “accident with wider consequences.” For more information on INES, see the IAEA’s website and this IAEA leaflet.


This site appears to be the best resource for accurate, timely, non-sensationalist information on the status of TEPCO’s battle to regain control of the crippled nuclear complex. I will post updates as I can, but you can also get the most recent information from this link.


TEPCO continues to install cables, transformers and distribution equipment to restore offsite grid power to Fukushima Daiichi reactors 1 and 2. Reactor 1 has now been included in the power restoration plan.

Chief Cabinet Secretary Edano said in a recent conference that plans are in place to use 30 water cannon trucks and fire engines to spray water into the reactor 3 spent fuel pool, and TEPCO is discussing whether to do the same for the reactor 1 spent fuel pool. The spraying work is to be done in the next few hours, after the cable work is completed.


Status of Fukushima plants

In Japan, engineers have laid a power line that can connect reactor 2 of the Daiichi facility to the off-site power grid, the International Atomic Energy Agency reported. Workers are working to reconnect the power to reactor 2 after they complete spraying water into the reactor 3 complex to provide additional cooling to the used fuel pool. Reconnecting to the power grid is expected to enhance efforts to prevent further damage at the plant.

Japan’s Nuclear and Industrial Safety Agency reported on Thursday that the backup diesel generator for reactor 6 is working and supplying electricity to reactors 5 and 6. TEPCO is preparing to add water to the storage pools that house used nuclear fuel rods at those two reactors.