51 Sailors from USS Ronald Reagan Suffering Thyroid Cancer, Leukemia, Brain Tumors After

[bananas]

37. It's not 100% effective, radioactive contaminants will still get through

In the discussion you linked to is a link to
http://www.nesc.wvu.edu/pdf/dw/publications/ontap/2009_tb/radionuclides_DWFSOM45.pdf
which says:

Reverse Osmosis (RO): Reverse osmosis effec-
tively removes many inorganic contaminants,
including heavy metals and radionuclides, such
as radium and uranium. RO can remove 87 to
98 percent of radium from drinking water. Similar
elimination can be achieved for alpha particle
activity and total beta and photon emitter activity.

When using an RO system to remove radionuclides,
performance depends on a number of factors,
including pH, turbidity, iron/manganese content
of the raw water, and membrane type. The pre-
treatment design depends on the quality and
quantity of the source water. Existing treatment
plants may already provide much of the required
pretreatment—for example, coagulation/filtration
of highly turbid surface water or iron removal for
well waters. RO can be cost effective for small
systems.