Regarding reactive sodium:

Under neutron bombardment, sodium-24 is produced. This is highly radioactive, emitting an energetic gamma ray of 2.7 MeV followed by a beta decay to form magnesium-24. Half life is only 15 hours, so this isotope is not a long-term hazard – indeed it has medical applications. Nevertheless, the presence of sodium-24 further necessitates the use of the intermediate coolant loop between the reactor and the turbines.

To which George Stanford adds: “As you can see, the author had a hard time finding significant disadvantages. The overall safety of the IFR concept is remarkable. gss”

The tax holiday on mining diesel makes it cheaper for BHP, and competition for scarce resources means more expensive for the rest (including low income families). Perhaps its subjective but I’d count these types of distortions as subsidies. Similarly I would count free pollution as a subsidee. Without such detailed full costing we keep getting economics that fails to count half the important stuff, and hence doesn’t properly do its job properly.

That is consistent with my understanding, that “spent fuel” from Gen II reactors’ can theoretically be used as fuel for Gen IV reactors. The trap would be building more Gen II reactors and leaving these costly (energy) investments stranded without a complete lifecycle of “good” (EROI) uranium.

Yet, the presentation notes which James Hansen reference re. Gen IV reactors were so optimistic as to be questionable. Some counter points can be found in a presentation by Michael Dittmar (http://ihp-lx2.ethz.ch/energy21/nuclearoption.pdf). Dittmar observes that no public scientific document seems to exist which quantifies the achieved longer term useful Pu(239) breeding factor! Lacking this data, Dittmar asks, “were all [previous and existing] fast reactors operated without achieving efficient breeding?”

Dittmar also states, that despite promising 30 years ago a claimed a theoretical increase of fissile material by a factor of 60, fast reactors are still not really a success story. 11 (out of 13) fast reactors are closed or not operating. No commercially functioning fast breeder exists today!

Helen Caldicott highlights the dangers of the highly reactive sodium and potassium that are used as coolant in Gen IV reactors. This is likely associated with the reluctance to transition to this generation.

And I’ve never been quite convinced that not levying a component of tax on diesel amounts to a ‘subsidy’, but anyway…if I had my way, I’d be digging that sort of hole using shaped nuclear charges; I reckon that’d bump up the EROEI a bit ;-)

Thanks for the Storm-Smith analysis – I’ll look this up.

(Current nuclear installations (approx 450 in number) produce in the order of ~15% of the world’s electricity (~5% of total power). Current Uranium reserves are in the order of ~60 years. Design life of a reactor is in the order of ~25-40 years. The Bush administration has granted permits to extend the life of current reactors to 60 years. Thus if we were to replace all current rectors with Gen 2 (or possibility unproven Gen 3 reactors) then the life of just the replacement rectors alone would see the depletion of the majority of feasible Uranium reserves (See Storm-Smith). Yet this leaves no scope for expansion of the nuclear energy share.

In short, the optimistic Gen 4 case (presented by Hansen) is essential for nuclear to further reduce greenhouse emissions. Current reactor designs are a drain and their multiplication will not reduce emissions over the century. Worse, expansion of current reactors will accelerate the depletion of fuel and reduce the energy return of energy investment (EREI) by producing reactors that will be stranded without a full lifetime supply of fuel.

I have continued fear for the suppression of support for renewables (on the relative scale required) and continued scepticism about optimistic assessment of the yet to be proved Generation four nuclear plant.

Barry, have you come across Storm Van Leeuwen? It’s hard to find a life-cycle analysis that are not tainted by the perceptions of the ubiquitous profit motive, hence I was interested in the Storm-Smith analysis (http://www.stormsmith.nl/). They include a detail estimation of uranium reserves (http://www.stormsmith.nl/report20071013/partD.pdf).

This operation will also require suspension of the laws that apply to all other operations (through the indenture act).

When we are turning to such uranium sources this early it does not bode well for the Uranium optimist argument regarding supply continuity with at reasonable EROI).

Chris O’Neil: the trouble is that the amount of water you’d have to run through the turbines would be far, far in excess of current capacity.

Not true (current capacity 7 GW while baseload capacity of Vic (6.5 GW), NSW and Qld is probably around 20 GW) but my point is that even with current capacity, there is still enormous potential for the existing hydro to support variations in output from wind generators.

That means you’d need to construct a pile of new or expanded buffer weirs to moderate the outflow. And that will be hugely environmentally contentious, given the locations of the overwhelming majority of our dams.

They certainly wouldn’t need to be anywhere near as big as the existing supply dams which are in more environmentally contentious locations than downstream of the generators. Of course, wind generation will need to be vastly greater than it is now before this needs doing.

Not to mention that if you tried to feed 10GW of generation capacity, you’d drain the country’s reservoirs in a week.

It would probably take a few weeks (7.2 per cent of electrical energy comes from hydro)A week without wind generation would be uncommon. The objective is not necessarily to do away with fossil fuel generation entirely, it is to greatly reduce the need for it which would happen if it’s not needed very often.

Recent events notwithstanding – let’s not throw out the free market baby with the reckless lending bathwater.

There are similarly only political reasons to not introduce renewables for a very healthy wedge. Economic arguments are out the window when you look at the kind of contraints on carbon proposed in today’s new blog. And politically it would be lapped up relative to nuclear.

Hmmmm, I’d suggest the fundamental reasons for the slowing of nuclear progress have been much more political than technical or economic.

Mark I don’t disagree – other than on the fuel supply contraints. Also that triple capacity is taking it to 60% of global electricity supply, which in my books is “taking over global base energy demand”.

I also have issue with the 2nd link – claiming that the increase in nuclear is much more feasible than in renewables…

In fact the entry itself shows that it only took a short amount of time for nuclear to go from zero to 20% of supply, so why would that be difficult for renewables. I’d suggest going from 20% to 40% is much more difficult, as evidenced in the failure of nuclear to progress past this point.