Jorge Stolfi
2011-03-23 02:40
The following plots show the partial evolution of physical quantities in the Fukushima Daiichi reactors #1, #2, and #3, during a the march/2011 incident. Note that the incident started on 2011-03-11 (friday), two days before the start of the plots.
This quantity is the water level, inside the (inner) reactor pressure vessel, in millimeters, measured from the top of the fuel elements. Negative values mean that the fuel is partly out of the water. The "B" reading is used in preference to "A".
This quantity is the pressure in the inner reactor pressure vessel, in kilopascals (kPa). A value of zero means the same as outside air pressure. Note that 100 kPa is aproximately 1 bar (one atmosphere). The "B" reading is used in preference to "A" or "C".
This quantity is the pressure (kPa) in the "drywell", the outer pear-shaped steel container that surrounds the reactor. A value of zero means the same as outside air pressure.
This quantity is the pressure (kPa) in the suppression container, the toroidal (donut-shaped) chamber below the drywell container. A value of zero means the same as outside air pressure.
This quantity is the temperature (Celsius) of the reactor's (inner) pressure vessel, taken at the injection nozzles. Note:The value is multiplied by 10 for clarity. The upper limit of the sensor's range (400 C) was briefly exceeded on some occasions.
This quantity is the temperature (Celsius) at the bottom of the reactor's (inner) pressure vessel. The remarks above apply to this limit also.
The water level and pressure data through 2011-03-17 come from the NIRS PDF document titled 'Condition of the plants of the unit 1-3 at FI site', fetched from the Nuclear Information and Resource Service site on 2011-03-22. That site says
Here is a document on the condition of Units 1, 2 & 3 from March 13-17, showing water levels and containment pressure, obtained through Citizens' Nuclear Information Center in Tokyo.
The data from that document was reformatted by hand into a separate text file fo each reactor, namely data-un1.txt, data-un1.txt, and data-un1.txt.
The gaps in the plots are data points that were blank or in the original document.
Data from 2011-03-22 onwards comes from the Nuclear and Industrial Safety Agency (NISA) News Releases.
For further information please contact the document authors.
The temperature readings from 2011-03-19 06:30 to 2011-03-22 15:30 were obtained from a scanned worksheet presumably prepared by TEPCO. After 2011-03-22 the data weer taken from the NISA bulletins (see above). The data was entered by hand to separate text files heat-un1.txt, heat-un1.txt, and heat-un1.txt.
Data from 2011-03-22 onwards (water level, pressure, and temperature) come from the Nuclear and Industrial Safety Agency (NISA) News Releases.
The core pressure of reactor #1 on 2011-03-16 6:00 was given as "0.62 MPa" in the NIRS table. That must be a typo. I have corrected (hopefully) the value to "0.162 MPa".
A few other values in the original source documents sand so far out from the neighbors (both before and after them) that they must be errors too. However it is not clear which are the correct values:
The plots were created by a gnuplot-based Linux shell script.
IMORTANT: These plots, scripts, and data files are provided "as is", for the reader's convenience, with no guarantee whatsoever. There may be errors in the original document and/or in my processing of it.
This page is not an official document of the State University of Campinas (UNICAMP). Neither me nor UNICAMP should be held responsible for any damages that may result from the use of this information. Corrections and suggestions are welcome.
Last edited on 2011-03-27 02:20:51 by stolfi
