"Burevestnik" Nuclear-powered cruise missile

GarryB wrote:

You are comparing apples with oranges... hydrogen fuel is used (with oxygen) because it is light and accelerates fast in the combustion reaction.

With ion propulsion it is different as it uses magnetism for acceleration... any material can be used... just strip off an electronic and it has an electric charge and can be manipulated easily by magnetic field.

Xenon was chosen because of its very high performance, but nitrogen is orders of magnitude cheaper and much more abundant... it is a bit like airships... hydrogen is cheaper and offers better performance but Helium was safer but expensive.

Old airships used Helium for safety but new airships can use hydrogen fuel cells, and lots of fire retardant technologies to minimise the risk of fire allowing much cheaper operations.

Nuclear thermal rocket has to use hydrogen, if it using helium ( second best candidate in the periodic table ) then the performance of it will be inferior compared to the chemical rockets.

A nuclear ramjet will use the gases the aircraft or missile the ramjet propels is flying through...

I don't think that the reactor has that much margin to locally shut it down and still operating.

I have never heard of any nuclear reactor that "drops cores" except in the Movies like Star Trek.

You need to have the reactor in an inactive state otherwise its engine will always be running... how would you store them?

I would expect in operation when the solid rocket booster engine fires and launches the missile control rods will be raised to expose the fuel rods and the nuclear reaction will rapidly generate heat, which is used to propel the missile... if the reactor overheats the control rods can be dropped down to stop the reaction... the engine wont go cold but will stop heating up and with the airflow drawing heat from the reactor it should stop overheating and start to cool down to a safer temperature...

In fact you could modify the reactor so that control rods remain in place and when the target is reached the missile climbs to 5,000m altitude and drops its warhead or 4-5 warheads over the targets and then the extra control rods can be raised to super heat the engine and melt it down so the missile crashes with a melted down reactor deep inside enemy territory somewhere as a bonus little present...

Operating at higher altitude might require more heat from the reactor so that extra heat potential could make it able to fly faster at higher altitudes too.

the rumors about failed tests from the Pankovo site might have some substance. The latest images (August) of the Pankovo facilities show that all equipment is removed from all sites - including the protective tent at the launch site itself! Only the large hangar at the former airfield remains. The removal of the equipment probably indicates that no further test are expected from there - at least for the foreseeable future. wrote:

Hole Today at 8:52 am No. Tests are finished because the weapon is operational. wrote:

Arrow wrote:

The US claims that all tests were unsuccessful.

Arrow wrote:The missile began testing in 2017 so it is strange that it would get so fast with the test program. Rolling up the infrastructure means closing the program.

GarryB wrote:

The reactor can be moderated with control rods to ensure it does not over heat, the coolant system delivering heat to the airflow could be ceramic material able to withstand enormous temperatures well beyond what the reactor heats the coolant material to. The heat transfer from the cooling system to the airflow will heat up if the airflow slows down... which will further heat the airflow and increase thrust... accelerating the missile and restoring air flow.

Means this engine has higher chance to fail than the hydrogen thermal rocket one, and if fail then it will not just simply impact the ground in one piece, but it will disperse the reactor core over a huge area prior of impact.
So, it is not so easy to test.

A cruise missile sized nuclear rocket could not contain sufficient hydrogen for an intercontinental flight...

Remark: all low earth orbit nuclear reactor system had core evacuation/ejection mechanism, to eject the reactor core to a safe parking orbit.
It is a basic feature : )

It doesn't fire them up... it accelerates them forward to a higher speed so it climbs to a higher orbit... it is a short term solution to a problem that will need to be solved at some stage.

rambo54 wrote:there are a whole lot of Russia fans in here.
Since years they are praising all the fantastic new systems like A-235 (without knowing what is really is), S-500 (every year a new adoration), 40N6 (since at least 4 years it should come around every moment), S-350 and so on.
To be a real fan sometimes turns down objectivity.

+
BTW: maybe it would have been better not to mention the withdrawl of the equipment from Pankovo and not to spoil some dreams

Singular_Transform wrote:

So, just summarise : the nuclear ramjet very dangerous, more dangerous than a nuclear rocket engine. If anything happens then it will disperse the core over a big area ( the material doesn't matter, the core in restricted airflow will heat up to positive infinite kelvin , and the control rods have no time to react).

Space reactor:

https://en.wikipedia.org/wiki/Kosmos_954

GarryB wrote:

A nuclear ramjet makes infinitely more sense... the only reason Pluto didn't go ahead was for ethical reasons... so I suspect it will have been restarted and the US will have some in a decade too.

Singular_Transform wrote:So, just summarise : the nuclear ramjet very dangerous, more dangerous than a nuclear rocket engine. If anything happens then it will disperse the core over a big area ( the material doesn't matter, the core in restricted airflow will heat up to positive infinite kelvin , and the control rods have no time to react).

Singular_Transform wrote:The nuclear fuel elements were made of refractory ceramic based on beryllium oxide, with enriched uranium dioxide as fuel and small amount of zirconium dioxide for structural stability. The fuel elements were hollow hexagonal tubes about 4 inches (10 cm) long with 0.3 inches (7.6 mm) distance between the outer parallel planes, with inside diameter of 0.227 inches (5.8 mm). They were manufactured by high-pressure extruding of the green compact, then sintering almost to its theoretical density. The core consisted of 465,000 individual elements stacked to form 27,000 airflow channels; the design with small unattached elements reduced problems related with thermal stresses. The elements were designed for average operation temperature of 2,330 °F (1,277 °C); the autoignition temperature of the reactor base plates was only 150 °C higher. The neutron flux was calculated to be 9×1017 neutrons/(cm2·s) in the aft and 7×1014 neutrons/(cm2·s) in the nose. The gamma radiation level was fairly high due to the lack of shielding; radiation hardening for the guidance electronics had to be designed.

So, the temperature margin of the Pluto reactor was 150 ceslius.

Its worked at 1277 Celsius, means only 150 Celsius means complete reactor meltdown.

the autoignition temperature of the reactor base plates was only 150 °C higher.

Big_Gazza wrote:

Singular_Transform wrote:The nuclear fuel elements were made of refractory ceramic based on beryllium oxide, with enriched uranium dioxide as fuel and small amount of zirconium dioxide for structural stability. The fuel elements were hollow hexagonal tubes about 4 inches (10 cm) long with 0.3 inches (7.6 mm) distance between the outer parallel planes, with inside diameter of 0.227 inches (5.8 mm). They were manufactured by high-pressure extruding of the green compact, then sintering almost to its theoretical density. The core consisted of 465,000 individual elements stacked to form 27,000 airflow channels; the design with small unattached elements reduced problems related with thermal stresses. The elements were designed for average operation temperature of 2,330 °F (1,277 °C); the autoignition temperature of the reactor base plates was only 150 °C higher. The neutron flux was calculated to be 9×1017 neutrons/(cm2·s) in the aft and 7×1014 neutrons/(cm2·s) in the nose. The gamma radiation level was fairly high due to the lack of shielding; radiation hardening for the guidance electronics had to be designed.

So, the temperature margin of the Pluto reactor was 150 ceslius.

Its worked at 1277 Celsius, means only 150 Celsius means complete reactor meltdown.

People quoting things they do not properly understand without having the sense to question what they read...

the autoignition temperature of the reactor base plates was only 150 °C higher.

What does this mean?  What are "reactor base plates" and why would they auto-ignite at 1,427 deg C? Consider that most stainless steels melt at 1,510 deg C, titanium at 1,670, zirconium at 1854, and tungsten at 3,400.  They certainly don't "ignite".  Any materials subjected to extreme temperatures will be refractories in any case, not metals.

Interpreting this as meaning that a 150 deg C temperature excursion on high side means a reactor meltdown simply confirms that you have no frigging idea what you are talking about.

Big_Gazza wrote:air-breathing engines do this everyday on a routine basis Helium or xenon?  WTF are you smoking?  

Suggesting a nuclear ramjet reactor core can't be built without imminent risk of meltdown due to high operating temperatures is junk "science".  Fuel elements and structural components can be build using refractory materials that can withstand several thousand degrees with minimal loss of structural strength.

The missile body can be insulated from the reactor heat by encompassing the hot components within a circular duct cooled by a seperate air intake.  

Singular_Transform wrote:What does this mean?  What are "reactor base plates" and why would they auto-ignite at 1,427 deg C? Consider that most stainless steels melt at 1,510 deg C, titanium at 1,670, zirconium at 1854, and tungsten at 3,400.  They certainly don't "ignite".  Any materials subjected to extreme temperatures will be refractories in any case, not metals.

Interpreting this as meaning that a 150 deg C temperature excursion on high side means a reactor meltdown simply confirms that you have no frigging idea what you are talking about.

https://en.wikipedia.org/wiki/Autoignition_temperature

It means that the steel burn like wood or coal.
And that temperature margin calculated for normal air pressure, the engine works with higher pressure, means the auto-ignition temperature is actually closer to the reactor normal operating temperature.

During iron/steel making there are materials used that float on the top of the steel to separate it from the air ( O2).

These are solvable problems(using ceramic or whatever), but the very basic characteristic will stay : in the event of restricted flow the reactor will melt like ice in a furnace.
So, if it ingesting a bird then it will melt down .

This is the reason why everyone wants to use this as a final doomsday weapon delivery system.

The US nuclear airplane supposed to use molten salt reactor with heat exchanger.

However the molten salt is soluble in water....

Big_Gazza wrote:

Keep barking up the tree all you like, but again you are misinterpreting what you read....

Metals don't "ignite" as you suggest, but they will undergo surface oxidisation when subjected to high temperatures in an oxygen-bearing environment. To actually combust in any real sense they need to be in particulate form (eg filings) or very thin sheets/ribbon.  Metallic components in a reactor will not catch fire... that is self evident, and any insistence to the contrary is just BS.  

like? what does it mean several thousands and if core is not moderated is there any limit of temp?

and if air stops flowing then?

Singular_Transform wrote:

Big_Gazza wrote:

Keep barking up the tree all you like, but again you are misinterpreting what you read....

Metals don't "ignite" as you suggest, but they will undergo surface oxidisation when subjected to high temperatures in an oxygen-bearing environment. To actually combust in any real sense they need to be in particulate form (eg filings) or very thin sheets/ribbon.  Metallic components in a reactor will not catch fire... that is self evident, and any insistence to the contrary is just BS.  

https://en.wikipedia.org/wiki/Oxy-fuel_welding_and_cutting#Cutting

In high temperature supersonic airflow the metal parts will burn away in the fraction of second, if the temperature is above the auto-ignition.


https://www.youtube.com/watch?v=7EGmrPiumEU

Big_Gazza wrote:

For those who doubt the Primitive Ruskies can build something like this, may I remind you that the Exceptionalists in the Clown Empire didn't think that a closed-cycle rocket engine running oxidiser-rich could be practical as the materials science challenges raised by flowing super-hot oxidising gases through the engine would be unsolvable.  They couldn't bring themselves to accept that Kuznetsov had solved the problem back on the late 60s with his NK-15/33s until they bench-tested one of his creations. Score one for the "primitives"...

Russians excel in metallurgy and materials science.  If anyone can solve the challenges to build a nuke-powered air-breathing ramjet engine, my money is on them...