There is a website which holds records about known aircraft crash sites in Czechia since 1918. Unfortunately it's all in Czech but with a decent translator you can dig a lot out of it (base data even without). It contains information about known circumstances of each crash site, its location and if possible also an information about artifacts found on the crash site. It can be particularly interesting for everyone interested in WW2 air war or for someone whose relatives were airmen who died somewhere over Czechoslovakia.
This is the link to the website.
Particularly interesting sections are these:
WW2 per type
WW2 per date
Unfortunately there is only one-way link between the map and the database and that is from the map to the database.
Of course not everything is in and with the time it's getting more and more difficult to search for what happened so long time a go...
One example of what you can find is this. Capt. Robert B. Holmes from 82th Fighter Squadron 78. Fighter Group 8. AF was shot down by FlaK on 16th April 1945 during an attack on Prague Ruzyně (Václav Havel Airport today) airport. He died in the cockpit of the plane and was burried in a near Ruzyně cemetery. His body was later moved by the US officials to a French US military cemetery and later back to USA per wish of the family. The fragments of his Mustang were found in a forest and neighbouring fields in the period of 2007 to 2012 including some rather large parts such as a piece of the wing with the US star still well visible on it. The people behind this website were later contacted by a man whose father was one of the first responders on the crash site (he was working on the field nearby). This family built a small memorial dedicated to Capt. Holmes on the crash site and they keep taking care of it.
There are some interesting records even after the WW2. For example this one. Two F-84F of the Luftwaffe crashed into a forest behind Czechoslovak frontier in 1959 due to navigation error in bad weather (both pilots managed to eject after first impact with the treetops). Long article (in Czech only) about this particularly interesting incident can be found here.
Is there something similar for other countries?
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?
An interesting approach to cooling the nuclear fuel; http://atomic-skies.blogspot.com/2013/10/the-liquid-jet-super-flux-reactor.html
If you're able to keep your fuel cooler, you can increase your neutron flux, and with it your power density. This could be highly important in applications where you're space or mass limited. Such as, for instance, a submarine, or a rocket engine.
I recently began a class on nuclear rocket propulsion, and one of the first topics covered was various nuclear rocket cycles. I'll do my best to explain them using amazing MS Paint drawings and words.
The first is the hot bleed cycle. In this cycle, some propellant does not go through the reactor, but is instead shunted off in a different direction. This is mixed with some of the propellant that has passed through the reactor, but not out the rocket nozzle, creating a relatively hot stream of propellant. This propellant is passed through a turbine, which then powers the fuel pump. After passing through the turbine, the propellant is exhausted overboard (on some designs this can be used for attitude control). Since the propellant that has passed through the turbine is at lower temperature than that which has passed through the reactor, some efficiency is lost. The NERVA design from the 1960s/1970s utilized the hot bleed cycle.
The cold bleed cycle is similar, except no propellant from the reactor is used to power the turbine. As a result, the propellant passing through the turbine is colder, thereby reducing turbine efficiency. However, this does have the advantage of producing less thermal stress on the turbine components. However, since the mass flow through the turbine is larger, the cold bleed cycle is less efficient than the hot bleed cycle.
The expander cycle cleverly avoids propellant wastage by passing all the propellant used in the turbine back into the reactor. This avoids expending propellant in the relatively low temperature turbine exhaust, and means that the expander cycle NTR has a higher specific impulse than the hot or cold bleed cycles.