Thursday, June 23, 2011

Another head-scratching development pops up in the Areva-Kurion water decontamination system

Can you explain this?

Infochart from NHK (annotated, of course)

The problem with Kurion's decontamination device just got a bit more curious.

As you may recall, the first operational run was stopped after just 5 hours because one of the zeolite cartridges reached its capacity of 4-5 milliSv/hr. Tepco was expecting the first cartridge change to take place after a few weeks to a months time.

There is a limit to the amount of radiation each cartridge can give off. If it collects too much cesium, it becomes a hazard for those handling it during removal and storage. The exposure contribution arising from the cartridge comes from a nearly homogeneous flux of photons at .66 million volts in energy. Gamma radiation travels far distances, so inverse square law applies. Workers will have to minimize their time and create as much distance as possible to keep their exposures to a minimum.

Testing resumed on Tuesday, and for some strange reason, the back end of the filter is absorbing all of the cesium from injected water instead of the front. Within a days time, radiation levels within the number six cartridge shot up to 3 times its expected capacity - at 15 milliSv/hr.

The no. 1 cartridge should be absorbing most of the cesium, and reaching capacity before any of the others. The no. 6 cartridge should have the lowest amount of isotope of the lot, because it is last in line.

Do you think Kurion installed the piping back-asswards? Are the first 5 cartridges devoid of any zeolite? Thus far, Kurion has been the weak link in this whole water decontamination effort. Areva hangs around trying to be useful somehow until this gets figured out, and Tepco's angst increases as radioactive water inches all the
way up to ground levels around the plant.

Read the NHK story here


  1. I think the first 5 cartridges have been tampered with (altered) or re-plumbed in an effort to get more water "filtered" ASAP.

  2. Valve likely set incorrectly from the beginning:

    The operator of the crippled Fukushima nuclear plant says it was unaware of an incorrectly opened valve that caused another disruption in its ongoing test run to filter radioactive water.

    Tokyo Electric Power Company found on Wednesday that a US-made device attached to the water treatment system had lowered concentration of radioactive cesium by just 10 percent the planned amount.

    The open valve meant that some contaminated water passed through only one of the system's 3 absorbent chambers. The valve is believed to have been incorrectly set since the device was installed.

    The amount of contaminated water on site is growing by about 400 tons a day, as fresh water is injected into reactors to cool them. The rainy season threatens to raise the water levels further.

    The test-run was interrupted on Tuesday after a pump to send water into French-made decontamination equipment stopped, also due to the wrong setting of a valve.
    Thursday, June 23, 2011 19:40 +0900 (JST)

  3. There ya go. Of course, it had to be a simple mistake to produce that kinda result. Let's see what happens next, maybe the darn thing will start working properly after all.

  4. Let's see, complicated system, challenging problem, miserable working conditions, unknown technology....

    Success is guaranteed,,,, to the sellers

  5. Obvious. They hooked it up backwards. Solved.