@ Red Bren

"Why does [it] need such high levels of subsidy and underwriting?"

In large part because provision of nuclear power is a major civil engineering programme, not unlike extending the railway network or building a new town. In part also it's because investment analysts and bankers are generally more tuned to next year's bonus than to providing a stable future. The commercial viability of any power generation depends greatly on government directives and controls and these uncertainties in long-term policy are best stabilised by having significant government involvement from the start.

Let's hope that someone has the courage and foresight to put some investment into Gen IV technologies, which have the potential to improve the conversion efficiency of uranium into energy and to denature the waste products.

Why

"Why does [nuclearl power] need such high levels of subsidy and underwriting?"

Because coal, oil and gas get huge subsidies.

Seriously. They are allowed to chuck all their waste into the atmosphere unprocessed. Does that save them a huge amount of cash? You bet it does! In fact, whenever it looks like they might have to clean up their act, they go screaming to their lobbyists who proclaim the imminent collapse of the economy if the politicians are daft enough to insist on it.

For at least half a century, the energy market has been totally rigged to make the politically acceptable forms of generation viable and everything else non-viable. All we are seeing now is a change in what's politically acceptable. (The same applies to renewables, whose subsidies come and go with the weather and tides.)

Regulation

In the 1970'sand 1980's the anti-nuke Chicken Littles were not successful at banning nuclear power, but were successful in suffocating it in federal regulation. No new nuclear plants have been started in the USA since sometime before 1980.

I question just what it is Obama thinks is unsafe about American nuclear power plants? Suspect this is just kissing up to his political base where it is an unquestioned fact that nuclear power is unsafe, and that man is causing global warming.

What is needed is a standardized plant design. Currently every plant is unique and requires massive engineering effort to build and continuously analyze for safety. At the start of WW-II the USA built destroyers the same way, every one was custom. Couldn't build many until they finally standardized on a single design. And then what was learned on one ship applied to others as well.

Why expensive?

Let's examine what happened at the Seabrook nuclear plant. Since it was close to the border of Mass. it required then Governor Dukakis' approval of evacuation plans for a couple of Massachusetts towns that lie within a 10 mile radius of the plant. Needless to say, Dukakis being opposed to nuclear power, he held up the opening for about 10 years. Guess how much money was being generated by the plant to repay the loan for those 10 years? That's right, zero dollars. Add to that time the delays in construction by assorted protest groups blocking access and you have a considerable cost overrun, which, along with over regulation of utilities, initiates the bankruptcy of the company in 1988. In the end, only half the planned capacity was ever finished resulting in lower efficiencies and higher costs.

Loan guarantees are not "subsidy"!

A loan guarantee will only pay money if the project fails and cannot repay its debt. The government will have to pay only in case of default, and that can happen only because of the government. The truth is that the GOVERNMENT is the ONLY force which can ruin a nuclear plant project. Many half built plants have been canceled because of government interference and "shifting goal posts" regulation. It goes as trivia that the government uses regulation as a club to beat the "less special" in the special interest pecking order. Nuclear power has been to the receiving end of this club far too many times and no one would start a plant without a loan guarantee - it provides at least some insurance against the government's game of picking winners and losers. Then the previous 18 billion in loan guarantees did NOT get awarded... so Obama's words are likely smoke and mirrors this time around too.

As an example, compare $5 trillion in fresh ~0% loans for the financial industry with the shaky "guarantees" for $34 billion 5% loans for nuclear power. More than 50% of nuclear cost is due to high interest and regulation cost, including long build times. Consider also the direct and indirect subsidies for "clean ebergy" which is from 3 to 5 times more expensive than nuclear. These subsidies aren't even loans they are gifts at the altar of Gaia, never to be seen again. For the last 10 years the amount of money gone with the wind approaches 100 billion... your money.

Reprocessing

The British and French have far more experience of reprocessing than the US and neither has managed to turn their businesses into profitable entities. The last time anyone in Britain looked at reprocessing it was with the view of determining if it was worth continuing at all. I suspect if Sellafield wasn't such a major employer in an area with sod/all other employment it would have been closed down by now.

As for why America never went down the reprocessing route, it was in part because they had a separate plutonium production industry based at Hanford. Their power industry quickly standardised on BWR and PWR systems using enriched uranium and long burn times producing relatively little bomb-friendly Pu239.

The UK on the other hand went with Magnox and AGR stations consuming natural uranium with on-load refuelling after short burn times. Their reactors produced plenty of Pu239 and the Magnox fuel HAD to be reprocessed because it corrodes rapidly.

So yes, reprocessing kind of makes sense in getting the most out of the fuel, but it won't make for cheaper energy and it will make for a lot of high-level actinide waste which will have to be processed and stored. Good luck with finding a permanent solution for that.