Wednesday, June 29, 2011

Some basic information about the water decontamination process in Fukushima nicely spelled out gathers some facts in a recent article that helps us understand certain challenges facing Tepco with the whole process.

  • There are about 100 pipe fitting points in the system. Water has been leaking at different times from different areas, and they have to troubleshoot the entire layout constantly, creating quite a headache.
  • Collectively, the piping system is about 4 kilometers in total length 
  • 16 tons of water per hour, brought in from a dam outside the plant, is being pumped in to cool the No. 1 through No. 3 reactors. 
  • With the recirculation system in place, TEPCO hopes to cool the reactors with 3 tons of water from outside sources and 13 tons of treated water per hour, drastically reducing the need for outside water, and to clean up the already contaminated water in the plant.
  • The utility needs to deal with about 110,000 tons of radioactive water in the plant--the equivalent of 200 25-meter swimming pools. 
  • Equipment made by Kurion Inc. of the United States is designed to absorb radioactive material using minerals. Equipment made by French nuclear engineering company Areva SA lowers the concentration of radioactivity using chemical agents. An oil separator and desalination equipment are also part of the unit.
  • Unless radiation levels are cut to below 1/10,000th, desalination equipment cannot treat radioactive salt water. Salt water was earlier used to cool the reactor cores.
  • The complexity of the unit, with its many pipes, valves and pumps, makes it susceptible to failure.
  • The use of Areva's equipment alone is expected to leave about 2,000 cubic meters of contaminated waste, enough to fill four to five 25-meter swimming pools.
  • How to ultimately get rid of the waste remains to be seen, with no applicable laws in place.

Radioactivity emitting from Areva's waste will be incredible, because it is an ungodly concentration of huge amounts of isotopes that were removed from the system. I expect this problem to become a major talking point, if and when the system goes full throttle. In full concentration, just a few cubic meters of that stuff would prove to be the most hazardous collection of radioactive waste encountered in the last few decades.


TEPCO halts reactor cooling system yet again

From NHK:

The operator of the Fukushima Daiichi nuclear plant has had to halt its new reactor cooling operation once again after finding more leaks in the system.

Tokyo Electric Power Company says it suspended operations on Wednesday morning after workers detected water leaking from 2 small holes in the system's piping.

It plans to restart the system as soon as it has fixed the faulty sections and checked for more leaks.

On Monday, TEPCO was forced to halt the system after only 90 minutes of operation due to water leakage from a displaced joint that connects plastic hoses.

The system was restarted on Tuesday afternoon, but small water leaks from another joint were later found.

The cooling system is designed to decontaminate radioactive wastewater accumulating at the plant and reuse the treated water to cool the reactors.

TEPCO says the system holds the key to stabilizing the reactors and reducing the amount of contaminated water.

But achieving stable operation of a system with 4-kilometers worth of piping is proving to be a challenge.

Wednesday, June 29, 2011 12:43 +0900 (JST)


  1. A desalination device that forms part of the crisis-hit Fukushima Daiichi nuclear power plant's key water decontamination system halted for a number of hours in the latest glitch at the plant.

  2. I have enjoyed reading your articles. It is well written. It looks like you spend a large amount of time and effort in writing the blog. I am appreciating your effort. .

    Safety Work Wear