NERVA - nuclear rocket

Orionblamblam

Orionblamblam

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From here: http://up-ship.com/blog/?p=8110

Showing the radiation levels around a NERVA. Note that the magnitudes (ten-to-the-holycrap power) are shown as faint large background numerals.
 

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my question to that grafik is
for several NERVA engine, was any danger of interaction of Neutron ?

i mean with Several engine under upperstage for NOVA and NEXUS booster
and Orbital use like Boeing IMIS 1968
 
Clustering NERVAs was something that the designers spent a fair amount of time puzzling over. If you look at early designs, the engines tended to be fairly close. As time went by, they got further and further from each other... because they *would* interact. Most spacecraft designers, in the end, tried to reduce the number of nuclear engines as much as possible, with "one" being preferred.

A number of designs had NERVAs staged in series... one used for trans-Mars injection, say, another used to brake at Mars, another used to boost away from Mars, etc. At first glance this may seem silly... the NERVA was capable of running for *hours* and it both weighed and cost a lot, so it seems silly to throw so many away after using them for so short a time. But the reason for this was simple: prior to being turned on for the first time, the nuclear reactor is fairly "cold," radioactively. But once it's turned on and run at full power for a while, it becomes, and remains, dangerously radioactive. Thus there is wisdom in simply chucking the damend thing overboad and letting it drift many, many miles away once you're done with it, and firing up a new one when needed.
 
This artist's concept from 1963 shows a proposed NERVA (Nuclear Engine for Rocket Vehicle Application) incorporating the NRX-A1, the first NERVA-type cold flow reactor. The NERVA engine, based on Kiwi nuclear reactor technology, was intended to power a RIFT (Reactor-In-Flight-Test) nuclear stage, for which Marshall Space Flight Center had development responsibility.

Source:
http://mix.msfc.nasa.gov/abstracts.php?p=1812


Cutaway drawing of NERVA engine.

Source:
http://dubious-maxims.blogspot.com/


Radiation flux around a NERVA nuclear rocket engine from Nuclear Space Propulsion by Holmes F. Crouch.
http://www.projectrho.com/rocket/radiation.php


Cross-sectional view of fuel elements for the experimental NERVA reactor.

Source:
http://large.stanford.edu/courses/2011/ph241/hamerly1/
 

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Greetings, all.
NASA published an end-project report on Rover in 1991, though much of it appears to be a collection of earlier materials. Large-scale experiments (as in giant white-hot gas plumes in the desert) ended in (I think)1968, though some modest control and refinement work went on a few more years. Warning! runs to about 270 pages in PDF.

Report No. CR-184279 [internal file no. 313-002-91-059]; available from the NASA tech reports server: http://ntrs.nasa.gov/

LNAL (Los Alamos) explored nuclear-thermal rockets in the mid-1950's as well. The project was called "Dumbo" and used a very different (fissile impreg. refractory metal foil) core design.

Report No. LA-2091 [contract no. W-7405-Eng. 36] Feb. 21 1957

LNAL maintained an excellent archive of non- and de-classified materials for many years, but a lot of it has been removed out of an excess of Homeland silliness. You can try I guess. If you can't find it and just have to have all 400 blurry copy of a copy of a carbon pages, let me know, I'll see what I can do.


cheers, 5arg0n
 
here a Link to PDF version to Report No. LA-2091 "DUMBO" nuclear engine


http://www.dunnspace.com/00339489.pdf
 
I found a in-deep report from 1991, It show all test Reactor used in Rover program
"Rover nuclear rocket engine program: Overview of rover engine tests"
9,7 MB PDF
http://ntrs.nasa.gov/search.jsp?R=19920005899&hterms=Nuclear+Furnace&qs=Ntx%3Dmode%2520matchallpartial%2520%26Ntk%3DAll%26N%3D0%26Ntt%3DNuclear%2520Furnace
http://hdl.handle.net/2060/19920005899
 
Michel Van said:
I found a in-deep report from 1991, It show all test Reactor used in Rover program
"Rover nuclear rocket engine program: Overview of rover engine tests"
9,7 MB PDF
http://ntrs.nasa.gov/search.jsp?R=19920005899&hterms=Nuclear+Furnace&qs=Ntx%3Dmode%2520matchallpartial%2520%26Ntk%3DAll%26N%3D0%26Ntt%3DNuclear%2520Furnace
http://hdl.handle.net/2060/19920005899
Click to expand...

5arg0n said:
NASA published an end-project report on Rover in 1991, though much of it appears to be a collection of earlier materials. Large-scale experiments (as in giant white-hot gas plumes in the desert) ended in (I think)1968, though some modest control and refinement work went on a few more years. Warning! runs to about 270 pages in PDF.

Report No. CR-184279 [internal file no. 313-002-91-059]; available from the NASA tech reports server: http://ntrs.nasa.gov/
Click to expand...

Can anyone point me in the right direction to find either of these? I'm making a mess of things trying to get the damn NTRS search function to cooperate.
 
SOC said:
Can anyone point me in the right direction to find either of these? I'm making a mess of things trying to get the damn NTRS search function to cooperate.
Click to expand...

I'd hazard a guess these are not available on NTRS since it came back up. Whether or not these will ever be available there again, along with other documents remains TBD imo.
 
The video that Triton linked to is an interesting overview of the NERVA program. It also includes the best explanation for a rocket's specific impulse that I've seen yet. I've always felt the unit used (s) is odd, making it difficult to grasp what Isp indicates.

But as the video says, an Isp of 1 s means that one pound of propellant can supply 1 lb of thrust for one second. A real 'duh' moment for me :eek:
 
SOC said:
Report No. CR-184279 [internal file no. 313-002-91-059]; available from the NASA tech reports server: http://ntrs.nasa.gov/

Can anyone point me in the right direction to find either of these? I'm making a mess of things trying to get the damn NTRS search function to cooperate.
Click to expand...

It would appear to be available on the Wayback Machine, www.archive.org.
 
Hobbes said:
The video that Triton linked to is an interesting overview of the NERVA program. It also includes the best explanation for a rocket's specific impulse that I've seen yet. I've always felt the unit used (s) is odd, making it difficult to grasp what Isp indicates.

But as the video says, an Isp of 1 s means that one pound of propellant can supply 1 lb of thrust for one second. A real 'duh' moment for me :eek:
Click to expand...
Yeah, Specific Impulse is a very non-intuitive unit.

IMO, it's basically only useful for comparing very different rocket types to see which one is "better". And even then, you need to ask "better for what?" Because for surface launch, you want lots of propellant mass flow but you don't need that mass moving very fast (low Isp), but once you're up in orbit you can use a much smaller mass flow at higher speed (moderate to high Isp).
 
Scott Kenny said:
Yeah, Specific Impulse is a very non-intuitive unit.

IMO, it's basically only useful for comparing very different rocket types to see which one is "better". And even then, you need to ask "better for what?" Because for surface launch, you want lots of propellant mass flow but you don't need that mass moving very fast (low Isp), but once you're up in orbit you can use a much smaller mass flow at higher speed (moderate to high Isp).
Click to expand...
There's a reason why it's called rocket science. But don't fret, Mr. Tsiolkovsky can be your friend, if you let him...
 

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