@allardjd-Nuclear Power.

John, as you know, I have misgivings regarding nuclear power, although some of your posts have gone some way to alleviating them. I'd be interested in your response to the following...

IT SEEMS like a no-brainer. Make uranium burn stronger, hotter and longer in nuclear reactors, and you'll need less fuel, and there'll be less waste to deal with when it has been exhausted. For decades, nuclear operators have done just that, but emerging safety and waste-disposal issues are raising questions about this approach. The latest high-efficiency fuel may prove to be unstable in an emergency, and so poses a greater risk of leakage of radioactive material into the environment. What's more, the waste fuel is more radioactive, meaning it could prove even more difficult than existing waste to store in underground repositories. To boost the efficiency of their reactors, operators have progressively enriched the uranium they use as fuel to increase its "burn-up" rate. This is a measure of the amount of electricity extracted from a given amount of fuel, and is expressed in gigawatt-days per tonne of uranium...

...60GWd/tU or more. At these burn up rates uranium rods should burn for about a year longer that todays best burn-up fuel. Such gains may come at a price though. A team at the national laboratory in Illinois presented findings on the behavior of high burn up fuel. They say that the fuels provide previously unforeseen safety problems. The danger would come if there were a sudden loss of cooling water as in the accident that led to the partial meltdown of a reactor core at three mile island.

And in the UK...

In 1976 the royal commission on environmental pollution declared that it would be morally wrong to make a major commitment to nuclear power without demonstrating a way of safely isolating radioactive waste. Yet the UK is about to embark on a program to build at least ten reactors while still lacking a disposal site for the waste that has accumulated over the past 50 years. What’s more, the spent fuel from these reactors will be far more radioactive than existing waste.

It seems that both the US and the UK are planning a new generation of reactors without having taken on board the lessons from the past about safety.

Thanks John that was very informative.

They do say though that the latest high-efficiency fuels may provide 'previously unforeseen' safety problems. It would seem therefore that the point of the article was that the impressive safety protocols you mention don't consider the new threat  and it's full steam ahead oblivious to the 'possible' danger.

Sorry I couldn't provide the full article, only a short piece was available on the web site and I didn't fancy typing out the rest of it from the mag.

The article seems to suggest that there is potential for another three mile island incident if there was a sudden loss of cooling water. And that the safety authorities have neglected this threat.

 

In 1976 the royal commission on environmental pollution declared that it would be morally wrong to make a major commitment to nuclear power without demonstrating a way of safely isolating radioactive waste. Yet the UK is about to embark on a program to build at least ten reactors while still lacking a disposal site for the waste that has accumulated over the past 50 years. What’s more, the spent fuel from these reactors will be far more radioactive than existing waste.

"What's your opinion of the situation in the UK..." 

To paraphrase one of the women who testified in the John Profumo scandal,  “Well, they would, wouldn’t they.”  What would you expect to hear from a “commission on environmental pollution” speaking in 1976, which was some years after Windscale and in the same country?

Nuclear waste disposal is not the huge issue some would make of it.  It will yield quickly to good engineering once the politicians and people like the Union of Concerned Scientists, Greenpeace, the Sierra Club and Friends of the Earth stop scaremongering and lobbying against ANYTHING remotely industrial that improves the human standard of living. 

All the nuclear waste ever produced in Britain could be safely stored on a piece of land not larger than a good-sized airport.  It’s not science, it’s engineering – the technology already exists.  All that’s lacking is the will to make use of it.  Too many are AGAINST everything, with no solutions to offer themselves.

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"It would seem therefore that the point of the article was that the impressive safety protocols you mention don't consider the new threat..."

But they do – read on… 

The Argonne National Laboratory is indeed very well respected.  They grew out of the organization that worked with Enrico Fermi to create the first controlled nuclear chain reaction in Chicago, way back in the 1940s.  (By the way, they used a small industrial tractor to withdraw and insert the control rods.  We’ve come a long way since then. ) They are top notch.

So is EPRI, but they are more of an applied science than a pure science outfit.  I’ve been to their labs and they do some very good work there.

Some of my response to your questions lie in the remainder of the story you linked…

The US nuclear energy's Electric Power Research Institute says that such a loss of coolant is not possible in modern reactors, but the NRC has still launched a three-year review of its safety standards.

"We are actively preparing to revise NRC's safety criteria to account for the burn-up effect," a commission spokesman told New Scientist.

That doesn’t communicate to me that they, “…don't consider the new threat.”

The two paragraphs above are a description of the process working.  Not described is the role of the ACRS, which I mentioned in my post above.  They speak for the scientific community and this issue falls well within their bailiwick. I would be astonished if the ACRS members were not aware of and sensitive to the issue postulated by Michael Billone’s 2003 test.

This next  “concern”,  addressed in the paragraph below is moot…

"Disposal is also a potential problem because the new, high-efficiency fuel is up to 50 percent more radioactive than fuel currently in use, thus generating far more heat during storage."

Part of the existing license amendment process considers the “tail” of the nuclear fuel cycle.  No plant would be granted a license amendment for a high-burnup core they could not store safely after use.  That’s already inherent in the licensing process and there’s nothing new here.

The amount of heat generated by spent fuel is an easily determined value.  This paragraph appears to have been included to strengthen the picture the author is trying to create that high burnup cores are unsafe, but this particular item is a red herring.  It’s a known issue whose effects are already well covered by the existing process. 

It should also be noted that both the radioactivity levels and the decay heat generated by spent fuel falls off exponentially with time.  That’s not to make light of either.  Spent fuel is lethally radioactive for many, many years and must be handled carefully, but the very high levels seen soon after shutdown do dissipate fairly quickly and are manageable. 

Spent fuel that’s been out of the RX for as little as 12-15 years has a heat load low enough that it can be placed in massive dry storage casks.  These can be stored outside and are air cooled using only natural circulation – no fans.  By that time the heat load is quite small.  The radiation levels are still very high and the very thick, high integrity casks provide the necessary shielding.  That process, in use at some US plants already, gets the older spent fuel out of the water and precludes the need for active cooling systems.

Peak cladding temperature during each of the forty-odd postulated accidents for which nuclear units are designed, is one of the most basic of NRC safety limits.  It’s an issue the NRC and the industry take very seriously.  Several kinds of loss of coolant accidents are included amongst the postulated accidents.  Utility operators must prove to the satisfaction of the NRC that the performance of the safety systems will keep fuel cladding temperature, and a multitude of other important safety parameter, within established limits.  If the NRC determines the standards need to be altered, it will do so and the industry will conform. 

"The article seems to suggest that there is potential for another three mile island incident if there was a sudden loss of cooling water. And that the safety authorities have neglected this threat."

I should point out that the fuel cladding is only the first of three boundaries between the fission products in the fuel and the public.  The other two are the Reactor Coolant System Pressure Boundary and the Containment Building.  Note that at Three Mile Island, only the first two were breeched – the containment building integrity was maintained and that 1979 accident resulted in no release of fission products except some relatively short half-life radioactive gases, which were deliberately vented to maintain the pressure within the containment building to design levels.  No one off-site was contaminated. 

The engineering and the industry have come a long way since 1979, making that kind of accident orders of magnitude less likely, and making the plants more robust in terms of being able to deal with it if one were to occur.

Yes thanks John. As they say there’s always two sides to a story.