In a joint press conference this morning, AU PM Scott Morrison, UK PM Boris Johnson and US President Joe Biden announced the acquisition of SSN and domestic nuclear manufacturing capability to replace our 6 SSK. This will substitute the previously programmed 12 “shortfin barracuda” SSNK (denuclearised barracuda SSN).
This is a massive change for Australia.
ABC news story
So far the reports are all saying the same thing.
The Joburg war museum (now Ditsong museum of military history) is a bit of an odd beast. Located right next to the Joburg Zoo, it's sort of small and kind of schizo in terms of content. It's also partly a monument to the fallen, partly a conference/events venue and partly a warehouse for all the odds and ends that the country has collected over the years and isn't sure what to do with.
Anyway, I went there recently with my son and brought back tonnes of photos. These will be dumped around the forum in the appropriate places (tanks, planes, big guns and small arms), with this thread serving as an overview.
The entrance is like the rest of the place: tucked away a bit and kind of pokey.
A few metres away, though, is an impressive monument to the British dead from the second Boer war. Nothing screams 'empire' like crushing your enemies and then putting up a huge shrine to your own war dead in their former city.
The museum is divided into a few big halls, some narrow glass-fronted galleries, an open park area and a central conference venue. One thing which should be noted is that two of the galleries do not allow photography. The interior pictures from these halls posted below are merely accurate replicas made from memory and a bunch of 1:72 models I happened to have lying around.
Brink Hall from the front and back. It has a number of aircraft and related gear, as well as stuff related to the Boer war and First World War. The Brink Hall is pretty much the first thing you're going to wander into, as its close to the entrance.
Between the two halls is a little artillery display. From here you can either go right to the open park area or straight into the Adler Hall.
The Adler Hall from a few angles. This one is dedicated to small arms, uniforms, a POW exhibit and just about everything else you can cram into a small hall and still fit. It also has a few vehicles (M3 light, Sexton, M4) that are opened up and/or have stairs so that you can look into them.
Past the uniform exhibit (which snakes around the sides and back of the hall) is a rather random exhibit on Cuito and the Border war. The cut-up Ratel in there has a driver's station with a display above it. The display shows grainy footage from the battle on a loop.
Just past the artillery display thingy there are a few naval objects on display. The most interesting is probably this Nazi mini-sub which we got from who-knows-where. The placement of the sub did something strange to my phone camera, so there are no photos with it in perfectly focus.
Most of the outdoor park stuff is going into other posts, so I'm just putting this there. These are the only two things that kids are allowed to clamber all over in the museum, and the little tykes seem to have stripped them down to bare metal over the years in doing so. I actually have lots of photos of these, as my little one was very insistent on spending time driving the jeep/flying the plane.
All in all: a decent little museum, and home to a few interesting odds and ends that I'll put up in other places.
Metal cooled reactors have several advantages over pressurized water reactors. For one, their power density is greater, additionally, the coolant is unpressurized, improving safety.
However, there are some downsides. The Soviets' Project 705 class submarines were powered by liquid metal reactors utilizing a lead-bismuth alloy as coolant. This alloy had a freezing temperature of roughly 400K. As a result, the reactors had to be run constantly, even while the submarines were in port (there were facilities to provide superheated steam to the reactors while the subs were docked, but they broke down and were never repaired). This reduces the lifetime of the reactor. Another coolant choice which has been used operationally is NaK (Sodium-Potassium). This alloy is liquid at room temperature, but reacts violently with water or air. I'm not an expert, but this seems like a bad thing.
It seems to me that if appropriate coolants could be found, it seems that liquid metal fast reactors could see more widespread acceptance. To my untrained eye, gallium looks like a good choice. Its melting point is relatively close to room temperature (~303K), and the boiling point is quite high (over 2600K). Also, gallium is less reactive than sodium or other alkali metals. It appears that there has been some research on this topic: http://www.sciencedirect.com/science/article/pii/S0149197000000640(unfortunately, the article is behind a paywall), and it looks quite promising.
Anybody have any opinions on this, or suggestions for alternative coolants?
During the Cold War, many neutral states made efforts to develop nuclear weapons. Very few of these resulted in a working bomb. One of these failures was Switzerland; http://nuclearweaponarchive.org/Library/Swissdoc.html
Interestingly, the Swiss also managed to cock up their nuclear power program; http://en.wikipedia.org/wiki/Lucens_reactor