NRC Approves New Nuclear Reactor Design 299
hrvatska writes "The NY Times has an article about the U.S. Nuclear Regulatory Commission approval of the design of Westinghouse's AP1000 reactor for the U.S., clearing the way for two American utilities to continue the construction of projects in South Carolina and Georgia. The last time a nuclear power plant in the U.S. entered service was 1996. The AP1000 was discussed on Slashdot a few years ago."
Re:Good, good. (Score:5, Informative)
If you haven't seen, the scale of construction on these projects is mind-bogglingly large. See here for some juicy pictures of the site under construction [nuclearstreet.com]. It's just astounding.
why isn't thorium being developed? (Score:5, Informative)
Re:Progress (Score:5, Informative)
Is an even older plant than Chernobyl.
Re:why isn't thorium being developed? (Score:5, Informative)
1. Current uranium-based reactors are more affordable than thorium reactors.
2. The path for licensing a thorium-based reactor in the US is exceedingly uncertain.
While a thorium-based fuel cycle may be a good idea, it's just not going to be done by any commercial enterprise today. The costs and risks are too high. When staring at a $5B initial investment cost, any electrical utility is going to favor the known route ... which, frankly, could just as easily mean building 10 natural-gas fired plants instead of 1 big nuke.
India, however, is going full-bore on a thorium-based fuel cycle, and has already built a few reactors that are capable of accepting thorium. Copied shamelessly [world-nuclear.org] from world-nuclear.org:
India's plans for thorium cycle
With huge resources of easily-accessible thorium and relatively little uranium, India has made utilization of thorium for large-scale energy production a major goal in its nuclear power programme, utilising a three-stage concept:
Pressurised heavy water reactors (PHWRs) fuelled by natural uranium, plus light water reactors, producing plutonium.
Fast breeder reactors (FBRs) using plutonium-based fuel to breed U-233 from thorium. The blanket around the core will have uranium as well as thorium, so that further plutonium (particularly Pu-239) is produced as well as the U-233. Advanced heavy water reactors (AHWRs) burn the U-233 and this plutonium with thorium, getting about 75% of their power from the thorium. The used fuel will then be reprocessed to recover fissile materials for recycling.
This Indian programme has moved from aiming to be sustained simply with thorium to one 'driven' with the addition of further fissile plutonium from the FBR fleet, to give greater efficiency. In 2009, despite the relaxation of trade restrictions on uranium, India reaffirmed its intention to proceed with developing the thorium cycle.
A 500 MWe prototype FBR under construction in Kalpakkam is designed to produce plutonium to enable AHWRs to breed U-233 from thorium. India is focusing and prioritizing the construction and commissioning of its sodium-cooled fast reactor fleet in which it will breed the required plutonium. This will take another 15 â" 20 years and so it will still be some time before India is using thorium energy to a significant extent.
Is it designed around passive nuclear safety? (Score:2, Informative)
Re:Is it designed around passive nuclear safety? (Score:5, Informative)
Sort of. Unlike Fukushima-style reactors, it doesn't require an external power source (like the DC generators that failed there) to cool the core following a shutdown, but it's not a purely passive system. Wikipedia's summary [wikipedia.org] is decent.
That ship sailed long ago (Score:5, Informative)
Almost all of the post 1970s technology in the AP1000 came directly from the nuclear division of Toshiba in Japan after merging with Westinghouse. It's technology bought off Japan instead of China but still looks like what you are worried about.
India is leading with Thorium at the moment and appear to have taken the US advances and added a couple of decades of development. Accelerated Thorium (mixed fuel such as expired weapons material or used uranium fuel rods in addition to thorium) holds paticular promise.
Re:Progress (Score:1, Informative)
Re:Progress (Score:5, Informative)
There exist no reactor in the western world that is capable of having runaway, "amplified" chain reaction. If you have done any research, you would realize that positive void coefficient reactors are even illegal in the US and almost no one builds them. (CANDU is the only one that has a small positive void coefficient mostly due to Pu during course of running the reactor, but that is accounted for).
The problem is ALL reactors produce enough power that they can cause the reactor to melt.
Fukushima reactors were OFF. There was NO nuclear reaction. They melted because of something called daughter elements produced in fission. I guess one can say, the meltdown occurred precisely due to the scenario you are talking about
The only "safe" passive ones are the ones used in satellites where no runaway fission is even possible because it is relying on the native radioactivity
DING DING! That is exactly why Fukushima had a melt down.
I also question your understanding of AP-1000. The design is clearly passively safe. It requires no moving parts to maintain cooling of the native radioactivity of the daughter elements.
Re:Progress (Score:5, Informative)
Then what generated the heat that caused the meltdown?
Radioactive decay, not fission.
It still has a cooling system with moving parts. Why?
I am by no means a nuclear expert, but my understanding is that:
(a) the passive cooling is for when the reactor is shut down but cooling off (think Fukushima), not while operating
(b) normally you need to move the heat over to the turbines in the most efficient way possible
Re:Progress (Score:5, Informative)
I'm astonished you compared averages and attempted to use this to backup your argument. Go and have a look at the distribution of power produced by each of those coal plants. You'll see that the majority of the 42% comes from a few large scale coal plants, equivalent in scale to the nuclear installations.
Re:That ship sailed long ago (Score:5, Informative)
Westinghouse employee here. The AP1000 final design certification was approved in 2006 [nrc.gov], and the design (including the predecessor AP600) began long before that (mid 90s).
Toshiba acquired Westinghouse in late 2006 [mediaroom.com]. Prior to that, Toshiba had partnered with our domestic rival, General Electric to build plants in Japan. We sell Pressurized Water Reactors (PWRs), they sell Boiling Water Reactors (BWRs). They're pretty different.
Even now that they own us, there is very little technical collaboration between our two entities. If there's a technological connection between Westinghouse and Toshiba that predates any of that, I'm certainly not aware of it.
Re:but (Score:4, Informative)
It only needs to be as safe as automobiles, and it far exceeds that.
Re:Progress (Score:5, Informative)
I'd call it "automated"
That's the first I've seen anyone characterize gravity as automation.
Since you appear to believe you have some credibility defining these terms, we should compare your thinking to those that actually do. To a nuclear engineer designing an emergency cooling system passive means no pumps, no power and no control. By that criteria the AP600/1000 designs are passive.
Everything about this emergency cooling system design relies on the integrity of containment. Containment, in this case, is a large free standing steel shell (as opposed to stressed concrete.) Threats to this vessel include kinetic impingement and corrosion. The former was the cause of a recent AP1000 design modification the NRC insisted on, based on a hypothesized attack involving an airliner. The latter can only be addressed through diligent and costly surveillance of the vessel throughout its lifetime ... just the sort of thing that tends not to survive bean counters.
The point is that there are plenty of legitimate criticisms that one can make of the design. Kibitzing about your peculiar notion of 'passive' isn't a very good one.
I think it is worth noting that the AP1000 design would have prevented core damage and radioactive release at Fukushima. The AP1000 design is exactly suited to the 'blackout' conditions that prevailed in Japan.
Re:Progress (Score:5, Informative)
No-one said passive systems were easy, in fact they are quite difficult to design and required modern computational power to produce. That is the stark difference between the old designs and the new designs such as the AP1000 - computing power. We can now model the nuclear, thermal, chemical and structural processes to a degree that was impossible when the first and second generation nuclear designs were produced. This is one of the reasons we can much more confident in the generation III+ reactors.
Re:Progress (Score:5, Informative)
Nuclear Engineering (student) here.
>The decay was an atom splitting into two smaller atoms and energy, which is fission.
Fission in the context of engineering refers to the use of neutrons to force atoms to split, not to naturally decaying isotopes.
>The question was of why would fukishima need active cooling when passive cooling is so "easy" to do.
Because it wasn't designed to use passive cooling. Passive cooling requires your reactor to be designed to facilitate it (all gen 3+ are designed like thisâ"I believe the NRC refuses to certify anything that is nonpassive). Passive cooling refers to not requiring power to run the coolant pumps or anything. The AP1000 is designed to using convection of steam inside the containment building to cool the reactor.
Re:Progress (Score:5, Informative)
Re:Is it designed around passive nuclear safety? (Score:5, Informative)
Re:Progress (Score:5, Informative)
Re:Progress (Score:5, Informative)