Your daily information sheet sheet from our friends at FEPC.
Update to Information Sheet Regarding the Tohoku Earthquake
The Federation of Electric Power Companies of Japan (FEPC) Washington DC Office
As of 12:00PM (EST), April 14, 2011
- Radiation Levels
- On April 13, TEPCO announced the result of the analysis of water samples from the spent fuel pool at Unit 4 of Fukushima Daiichi Nuclear Power Plant taken on April 12. The concentration of radioactive nuclides were as follows:
o TEPCO also announced the temperature of the pool water was approximately 194 degrees Fahrenheit when the samples were taken.
Nuclides (half-life)
Concentration (Unit : Bq/cm3) Sampled on April 12 Sampled on March 4 I-131 (8 days)
2.2 x 102 Under the Detection Limit Cs-134 (2 years)
8.8 x 101 Under the Detection Limit Cs-137 (30 years)
9.3 x 101 1.3 x 10-1
o The concentration of radioactive nuclides from the seawater sampled at the screen device (installed to remove waste before the intake of seawater) of Unit 2 and sampled near the seawater discharge point (south side) of Fukushima Daiichi Nuclear Station were as follows:
Nuclides (half-life)
Concentration (Unit : Bq/cm3) Ratio Sampled at the screen of Unit 2 at 8:25AM on April 13 (a) Sampled at south side discharge point at 2:00PM on April 13 (b) Maximum Permissible Water Concentration (c) a / c b / c I-131 (8 days)
1.0 x 102 9.7 x 10-1 4.0 x 10-2 2,500 24 Cs-134 (2 years)
5.5 x 101 1.4 x 100 6.0 x 10-2 920 23 Cs-137 (30 years)
5.5 x 101 1.4 x 100 9.0 x 10-2 610 16
o At 8:00PM (JST) on April 14, radiation level at main gate (approximately 3,281 feet from Unit 2 reactor building) of Fukushima Daiichi Nuclear Power Station: 71 micro Sv/hour.
o At 8:00PM on April 14, radiation level at west gate (approximately 3,609 feet from Unit 2 reactor building) of Fukushima Daiichi Nuclear Power Station: 36.8 micro Sv/hour.
o Measurement results of environmental radioactivity level around Fukushima Nuclear Power Station announced at 7:00PM on April 14 are shown in the attached PDF file. English version is available at: http://www.mext.go.jp/english/radioactivity_level/detail/1304082.htm
o For comparison, a human receives 2,400 micro Sv per year from natural radiation in the form of sunlight, radon, and other sources. One chest CT scan generates 6,900 micro Sv per scan.
- Plant Parameters
Unit 1 Unit 2 Unit 3 Unit 4 Unit 5 Unit 6 pressure inside the reactor core (gauge pressure, MPa) 0.423 -0.016 -0.017 – 0.003 0.010 4/14 12:00PM
4/14 12:00PM
4/14 12:00PM
– 4/14 8:00AM
4/14 8:00AM
pressure inside the primary containment vessel (absolute pressure, MPaabs) 0.190 0.090 0.1040 – – – 4/14 12:00PM
4/14 12:00PM
4/14 12:00PM
– – – water level inside the reactor core (meter) *1 -1.6 -1.5 -1.8 – +1.842 +2.268 4/14 12:00PM
4/14 12:00PM
4/14 12:00PM
– 4/14 8:00AM
4/14 8:00AM
temperature of the reactor vessel measured at the water supply nozzle (degrees Fahrenheit) 392.5 *2
309.4 193.8 *2
– – – 4/14 12:00PM
4/14 12:00PM
4/14 12:00PM
– – – temperature of the spent fuel pool (degrees Fahrenheit) – 159.8 – – 95.9 89.6 – 4/14 12:00PM
– – 4/14 1:00PM
4/14 1:00PM
the temperature directly above the spent fuel pool by thermography measurement (degrees Fahrenheit) 96.8 – 138.2 145.4 – – 4/14 7:40AM
– 4/14 7:40AM
4/14 7:40AM
– – temperature directly above the primary containment vessel by thermography measurement (degrees Fahrenheit) 91.4 – 154.4 – – – 4/14 7:40AM
– 4/14 7:40AM
– – – temperature directly above the second containment building by thermography measurement (degrees Fahrenheit) – 87.8 – – – – – 4/14 7:40AM
– – – – Amount of water in total shot/injected to the spent fuel storage pool (tons) 90 419 – 434 5,263 1,816 – – as of 4/14 5:00PM
as of 4/14 5:00PM
as of 4/14 5:00PM
as of 4/14 5:00PM
– – *1: Minus figure means that water level is below the top of the fuel rods.
*2: This figure is under investigation.
- Fukushima Daiichi Unit 1 reactor
o As of 6:00PM on April 14, injection of nitrogen gas into the primary containment vessel to prevent an explosion by accumulated hydrogen gas continues.
o As of 6:00PM on April 14, the injection of freshwater into the reactor core continues.
- Fukushima Daiichi Unit 2 reactor
o As of 6:00PM on April 14, the injection of freshwater into the reactor core continues.
- Fukushima Daiichi Unit 3 reactor
o At 3:56PM on April 14, TEPCO began to shoot freshwater aimed at the spent fuel pool, with a specialized vehicle normally used for pumping concrete, until 4:32PM (approximately 25 tons in total).
o As of 6:00PM on April 14, the injection of freshwater into the reactor core continues.
- Fukushima Daiichi Common Spent Fuel Pool
o At 7:20AM on April 14, the temperature of the spent fuel pool: 82.4 degrees Fahrenheit.
- Others
o At 11:00AM on April 13, the removal works of debris at the site began, with a remote controlled excavation machine, until 4:10PM.
o At 12:10PM on April 14, TEPCO installed a double layered silt fence at the ocean side of the screen device of Unit 1 and 2 and near the north side of south sea wall of Fukushima Daiichi Nuclear Power Station in order to contain the spread of discharged radioactive water.
Our official sources are:
- Office of The Prime Minister of Japan
- Nuclear and Industrial Safety Agency (NISA)
- Tokyo Electric Power Company (TEPCO) Press Releases
- Ministry of Education, Culture, Sports, Science and Technology (MEXT)
Its lonely here today. Jeffrey, as always, thanks!! I appreciate your compilations.
People must be getting on with their lives. Japan is slowly getting back to normal. But all that is needed to stir up the media would be another hydrogen explosion or someone finding a three-eyed fish.
“People must be getting on with their lives. Japan is slowly getting back to normal. But all that is needed to stir up the media would be another hydrogen explosion or someone finding a three-eyed fish.”
13,500 dead & 14,000+ missing – yeah, yeah, but what about all that RADIATION!!!
“temperature of the reactor vessel measured at the water supply nozzle”
As a mechanical engineer I’d just like to point out that the area near the water *supply* nozzle will be the coolest in the entire reactor vessel. If that temperature is still 300+ degF there’s obviously still a long ways to go before you even think about “cold shutdown”.
I think the figure of 200 degF inside the fuel assemblies has been thrown around as the point at which cold shutdown is considered achieved. Of course, there may not be any assemblies left….
I wonder if you can directly measure the temperature in the core of the reactor during operation? Do they make sensors that can survive those conditions?
If the pressure in the reactor vessel is .423 MPa gauge, then the temperature of the liquid water filling the bottom of the core is no greater than 309 degF (yes, I shall do penance for the mixed units). Presumably the temperature “at the water supply nozzle” is either measured a short distance from said nozzle, or at a time when water is not being actively supplied, or both – there’d be no point in measuring the temperature of the nozzle body during active flow, as that would be dominated by the water supply rather than the core environment.
So, water boiling at 309 degF in the core of Unit 1, with the steam picking up an additional 84 degF from the exposed core above the water level. That’s not horrible; the water-zirconium reaction producing free hydrogen should not occur at that temperature. But it’s not cold shutdown, which is classically defined as 212 degF or below (i.e. no boiling, only evaporation, even at ambient pressure).
It would help if TEPCO would publish the rate/amount of water injection to the core. Decay heat in Unit 1 should be down to about 2.45 MW by now, requiring 78 tonnes/day of water to maintain the stated temperature and pressure.
John, what do you make of the NRC report of 26th March saying in their Unit 1 assessment “There is likely no water level in the core barrel”, due to salt and other blockage. They also note “Vessel temp readings are likely metal temp which lags actual conditions.” They seem to be saying the core itself was probably at a far higher temp than the readings suggest. Though that report is now very dated.
http://www.fairewinds.com/content/nrc-report-official-use-only-fukushima-assessment-march-26th-2011
It is true that impaired circulation in the core will impede water cooling, and also that thermal inertia will delay response of the temperature sensors. This is mostly relevant in a dynamic environment where coolant flow, heat generation, etc, are changing rapidly. In that case, the temperature sensors will mostly tell you what conditions were some hours ago (they might have gotten worse), and pumping more water in will take more hours to have any effect (things might get worse still…)
At present, it looks like reactor #1 is fairly stable with no rapid changes in temperature or pressure, so these effects are less significant. The core is still generating a steady 2.4 megawatts of heat, every ton of water injected and allowed to boil off will carry away 0.75 megawatt-hours of heat, and the core cannot indefinitely sustain large internal temperature differentials. If they can pump more than 3.2 tons/hour to the core (excluding leakage) or even just the primary containment, they will eventually get to cold shutdown.
Cryptome have a new batch of overhead pictures up at:-
http://cryptome.org/eyeball/daiichi-npp9/daiichi-photos9.htm
The 5th and 6th pictures (of unit 4) are particularly troubling, seemingly showing some bolts retaining the steel containment vessel dome having failed.
Now, to be sure, this is not the reactor vessel itself, but it raises a lot of questions.
It was removed for servicing, if you look at the plant design they defuel the reactor by lifting the concrete caps off the reactor, then removing the yellow steel head you can see in the picture and locating it to the side platform opposite the spent fuel pool. Then they flood the space where the head and caps were with water and transfer the fuel from the reactor to the fuel pool.
Bottom line, it was moved by that huge crane, not any kind of explosion.
Update on the above cryptome pictures – unit 4 was apparently completely de-fueled, so the offending bolts could have been just loosely in place.
Assuming that the concrete plug had been moved for access, is the dome resting in-situ or has it also been moved for access?