Correct me if I am wrong but my understanding is that pure water does not become radioactive. Rather, it emits radioactivity from material that is suspended or in solution in it. Hence the steam in the turbine, having recently been in the reactor, presents no radiological safety problem. That this is accomplished by the action of a “water polisher” employing HEPA and carbon filters in the primary (RV) coolant loop.
Where I am leading is that the polishing units in the plants may be inoperable and, if operable, may be in an environment where they cannot safely be serviced. However, the function of a water polisher could be employed outside of the plant to separate radioactive material from the water in the trench and from water they are proposing to store in tanks at a remote location on site. These tanks are described as being piped to each of the buildings for temporary water storage.
My thought is to employ one or several water polishing units to separate the non-radioactive water and dispose of it in the sea. This would lessen the difficulty caused by finite storage capacity and allow more discretionary use of water for cooling. It could later be employed in the remediation of ground water at the test wells used for sampling.
More when I have had some sleep. liam