"my understanding is the LWR are the most simple and cost...

"my understanding is the LWR are the most simple and cost effective method"
That is where I disagree!

The US has been closing LWR plants for some time now, they say they are not competitive with cheaper Gas fired plants?
Cheap fracked gas has caused this dilema, gas is supposed to be about half the GHG of Coal, but if they actually took into account the amount of methane gas loss into the atmosphere in the fracking extraction process then there would be little difference between fracked gas power production and coal fired plants.

If the US is serious about Climate Change then Gas fired plants are not the answer, but if you want LWR's to be even cheaper to run in the future then PRISM comes into that equation.

I think we could see PRISM well before the time frame of2025-2030 that you gave, GE have stated, that once they had the license, they could build a plant every two years!
If the US wants an answer to the used nuclear fuel problem, then PRISM is the answer, building more LWR's is not!

Using what LWR's they already have is part of the answer, until such times as they reach their use by date and they are shut down!
Once all LWR's are shut down forever, the used nuclear fuel problem the US has now, will become much much less of a problem for them, by using PRISM reactors and possibly some  time in the future, other technologies will have come to the forefront, but PRISM has to happen either way, to allow for the cleanup of the used nuclear fuel from LWR's!

PRISM will be much cheaper to run in the end especially when you consider that the recovered Uranium from used nuclear fuel can be used again over and over in the existing LWR's  without having to spend one more cent on buying Uranium or enriching it for that matter with the added plus of getting power from the PRISM reactor by burning Plutonium, I understand that some here don't like me saying that, but what they fail to realise is that that LIS technology will be used to recover that Uranium from the used nuclear fuel in that it will either enrich it to a higher degree to overcome the actinides effect on the used nuclear Uranium, "OR", and this I believe would be the preferred method, if it works? is to only extract the Uranium from the combination of Uranium and actinides derived from the RepU and it would already be LEU or HEU, depending on what type of reactor  the used nuclear fuel came from, only 5% by weight would have been used in the reactor, so about 95% is still usable Uranium, whether it be LEU or HEU.

If it is HEU, then I believe they will down blend it with DU (U238) to bring it back to LEU levels.

In the end this would mean that instead of GLE only picking up a percentage of the world enrichment market using laser enrichment, it will get to supply just about all of the LEU used in todays LWR's by using Laser Isotope Separation (LIS aka  Separation of Isotopes using Laser EXcitation = Silex)