WEB UPDATE AS OF 2:15 P.M. EDT, TUESDAY, MARCH 15:
An explosion at Unit 2 of the Fukushima Daiichi plant earlier today has damaged the suppression chamber, which holds water and steam released from the reactor core. Personnel not directly supporting recovery efforts have been evacuated from the plant, with about 50 employees remaining, principally to restore cooling water in the reactors. (The suppression pool is the torus shaped ring that sits below primary containment. Steam from the reactor is redirected here when the Main Steam Isolation Valves (MSIVs) are closed as in a reactor trip from the earthquake. It is filled partially with water and is used to 'suppress' the steam coming from containment. Basically the steam is injected into the water to cool it off and capture fission products in the event of an emergency. When the suppression pool water gets enough energy it too becomes saturated and boils. This whole process increases pressure in this closed environment. When they talk about venting this is where it comes from. The air/steam goes through a series of HEPA and charcoal filters through a vent stack -i.e. not into secondary containment.)
Later in the day, water level inside the Unit 2 reactor was measured at 1.7 meters below the top of the fuel rods, but it was rising as workers pumped sea water into the reactor, reports said. (Fuels rods are typically 12 to 14 feet in length and depends on design and type. BWR designs are more robust at becoming uncovered than a PWR design.)
Tokyo Electric Power Co. said that an oil leak in a cooling water pump at Unit 4 was the cause of a fire that burned for approximately 140 minutes. The fire was not in the spent fuel pool, as reported by several media outlets. Unit 4 was in a 105-day-long maintenance outage at the time of the earthquake and there is no fuel in the reactor.
All four reactors at the Fukushima Daini power plant are shutdown and reactor coolant systems are keeping the reactors safe. (Awesome.)
Residents have been evacuated from the area surrounding the facility and they have been given potassium iodide tablets as a preventive measure. The ingestion of the tablets can help prevent the accumulation of radioactive iodine in the thyroid. (Radioactive iodine can be used in medical patients that have hyperthyroidism. If the dose is measured correctly by the doctor then it will slow the overactive thyroid to the correct level. The potassium iodide is to keep people from inhaling the radioactive iodine and receiving too much of a dose. Instead, if your body has too much iodine it will just flush it out of your system. Take the nonradioactive potassium iodide first and your body will uptake this first.)
The U.S. Nuclear Regulatory Commission has sent 11 experts to Tokyo to provide assistance requested by the Japanese government. Two reactor experts were dispatched Saturday; others began departing Monday. (Keep in mind that this is an industrial machine. All we care about is the alternating current that comes out of the socket and into our homes. The amount of engineering, time, labor and know how that go into keeping all this working is mind boggling. It is going to take a good long time to look at all the facts and data to assess everything that has been happening these past couple of days. It is premature to make any sort of claims that anyone knows exactly what has happened. Anything that comes out other than pure observations are educated guesses at best. Most of the claims that come out are VERY misinformed. If anything to do with energy was simple do you think we would have to worry about it so much these days? Patience grasshopper. Time tells all.)
Energy Secretary Steven Chu said today that nuclear energy is safe and important to the country's energy portfolio. Americans should have full confidence that the United States has rigorous safety regulations in place to ensure that our nuclear power is generated safely and responsibly.
In testimony before the House of Representatives, Chu said: Safety remains at the forefront of our effort to responsibly develop America's energy resources, and we will continue to incorporate best practices and lessons learned into that process. He said the country must rely on several energy sources, including nuclear.
Sen. Jeff Bingaman, chairman of the Energy and Natural Resources Committee, said in a statement, I think undoubtedly they'll (Nuclear Regulatory Commission) be taking a fresh look at the safety precautions and provisions that are in place, in light of whatever is learned from the Japanese. I hope that the Commission will quickly reach some conclusions about whether the safety precautions and provisions that it has insisted on are adequate for the future.
UPDATE AS OF 10:20 A.M. EDT, TUESDAY, MARCH 15:
The level of radioactivity at the Fukushima Daiichi nuclear power plant has been decreasing, according to the International Atomic Energy Agency.
At 8 p.m. EDT March 14, a dose rate of 1,190 millirem per hour was observed. Six hours later, the dose rate was 60 millirem per hour, IAEA said. (1,190 millirem/hr is high. 1,190 millirem/hr is scary. At that level it would take less than 5 hours to get your max dose for a year as a radiation worker. 60 millirem/hr is still high. It is 150% the dose from a source I used when administering undergraduate laboratories. Limit time, maximize distance, use shielding -- that's protocol. These are still not levels that will affect health. If you were exposed to 1.1 rem/hr for several days, yes this would incur radiation sickness symptoms -- nausea, headache, diarrhea, fatigue, and others depending on severity of dose.)
About 150 residents near the Fukushima Daiichi site have been checked for radiation and 23 have been decontaminated. (Radiation likes to stick to things. Clothing, being fibrous is a great place for little particles -- almost like dust -- to get lodged. The same goes for tobacco plants which are pretty fuzzy. Radon is a gas that seeps up from the ground and 'sticks' to tobacco plants. These residents would likely need to change clothes (clean the ones they were wearing) and get a big scrub brush out and go to town with good old soap and water. I don't know at what levels they are calling contaminated but its kind of like spilling ketchup on your shirt. Your favorite shirt has now been 'contaminated' with ketchup but it doesn't mean its unwearable or needs to be gotten rid of. Same for radiation. You could have just a few particles sticking and if its enough then you take it off to be put in the wash. Interestingly enough radiation 'sticks' to synthetics better than natural fibers like cotton. I learned this the hard way on a tour of an awesome facility at Idaho National Lab once. It's funny to think back now about having to take off your clothes in front of people to be measured but it was pretty embarrassing at the time :-).)
Japanese authorities have distributed potassium iodide tablets to evacuation center (see this page for more information on potassium iodide). If taken within several hours of ingesting radioactive iodine, potassium iodide can protect the thyroid gland. (Their government is on top of it. Its a preventative measure but kudos nonetheless.)
UPDATE AS OF 9:15 A.M. EDT, TUESDAY, MARCH 15:
Units 1 and 3 at Fukushima Daiichi are stable and cooling is being maintained through seawater injection. Primary containment integrity has been maintained on both reactors.
The Japan Atomic Energy Agency (JAEA) reported an explosion in the suppression pool at Fukushima Daiichi Unit 2, at 7:14 p.m. EDT on March 14. Reactor water level was reported to be at 2.7 meters below the top of the fuel. The pressure in the suppression pool decreased from 3 atmospheres to 1 atmosphere. Radiation readings at the site increased to 96 millirem per hour.
Dose rates at Fukushima Daiichi as reported at 10:22 p.m. EDT on March 14 were:
(These are instantaneous readings. I certainly assume one is being exposed to these. Still, it's high enough to give me the willies.)
- Near Unit 3 reactor building 40 rem/hr (high)
- Near Unit 4 reactor building 10 rem/hr (high)
- At site boundary 821 millirem/hr. (high)
- Kitaibaraki (200 km south of site) 0.4 millirem/hr.
We are working on getting updated information on radiation and dose rates at and near the plant.
Station personnel not directly supporting reactor recovery efforts have been evacuated, leaving approximately 50 staff members at the site. Operators are no longer in the main control room due to high radiation levels. (Staff and workers are staying safe and informed. This is awesome. They're running a tight ship. This is already way better than Chernobyl where firefighters were uninformed about radiation levels and also that water wasn't helping in their case.)
Safety relief valves were able to be re-opened and seawater injection into the reactor core was restarted around 1 a.m. EDT on March 15 and is continuing.
At Unit 4 on March 14 at approximately 8:38 p.m. EDT, a fire was reported in the reactor building. It is believed to have been from a lube oil leak in a system that drives recirculation water pumps. Fire fighting efforts extinguished the fire. The roof of the reactor building was damaged. (Just like an industrial facility -- since it is one -- there are dangerous things. Nuclear continues to maintain some really impressive safety records.)
All four reactors at Fukushima Daini are being maintained with normal cooling using residual heat removal systems. (Again, awesome).
Tuesday, March 15, 2011
NEI Update with Commentary
Update from NEI throughout the day today (I will supplement with italics):