It will be sprayed up the sides and all around reactors. If the three-week exam is successful, the spraying will continue for as prolonged a time as necessary. Sounds like a great product that will limit the amount of radiation leaking from the plant, but it is bound to raise radiation readings there also.
I will be able to take my own measurements within a week here in the Philippines, and will update them regularly on this blog. I will also be delighted if it becomes unnecessary to worry about the whole situation by then. We will see. Here's another idea being considered at Fukushima -
...using a tanker to ferry the highly radioactive water away from unit 2. If this can be accomplished, they will make a lot more progress with this particular reactor.