B-52 testbed for a nuclear turbojet

[aam641]

You may have already seen this at http://www.aerospaceprojectsreview.com/blog/?p=872

... in 1961 GE proposed modifying a B-52G to serve as a testbed for a single XNJ140E-1 nuclear turbojet. The very large engine would be contained in a nacelle attached to the port rear fuselage. With eight conventional J57 chemical turbojets, the testbed aircraft would be capable of putting the engine through the altitude and airspeed paces that would be expected of it in the NX-2 nuclear powered bomber demonstrator (35,000 feet and Mach 0.8). This configuration would be capable of sustained nuclear flight.

Attached is a picture of what looks like radiation doses around the nuclear engine. My quick conversion gives me 1000 Gy/hr in zone I and 5 Gy/hr in zone VIII. Could somebody knowledgeable check these numbers, because they look very very high, even for the 60s.

 

[fightingirish]

Flashback: Boeing B-52G Nuclear Engine Testbed

In 1946, The Department of Defense (DoD) initiated a joint project between the Atomic Energy Commission (AEC) and the Air Force known as the Aircraft Nuclear Propulsion (ANP) Program. Based on

www.afmc.af.mil

PDF: https://media.defense.gov/2023/May/...K_B-52 TESTBED.PDF/FLASHBACK_B-52 TESTBED.PDF
Pictures:

https://media.defense.gov/2023/May/02/2003213639/500/500/0/230502-F-ZS999-1003.JPG

https://media.defense.gov/2023/May/02/2003213635/500/500/0/230502-F-ZS999-1001.JPG

 

[Ravinoff]

Flashback: Boeing B-52G Nuclear Engine Testbed

In 1946, The Department of Defense (DoD) initiated a joint project between the Atomic Energy Commission (AEC) and the Air Force known as the Aircraft Nuclear Propulsion (ANP) Program. Based on

www.afmc.af.mil

PDF: https://media.defense.gov/2023/May/02/2003213640/-1/-1/1/FLASHBACK_B-52 TESTBED.PDF/FLASHBACK_B-52 TESTBED.PDF
Pictures:

https://media.defense.gov/2023/May/02/2003213639/500/500/0/230502-F-ZS999-1003.JPG

https://media.defense.gov/2023/May/02/2003213635/500/500/0/230502-F-ZS999-1001.JPG

The good old "just bolt it on the side" method of engine testing, extra 60,000lbs bolted on asymmetrically pushing 35,000lbs of thrust might make handling a bit of a challenge.

Though for the Avro Arrow program, Canadair borrowed a B-47 Stratojet and did exactly this setup with an Orenda Iroquois. Reportedly a nightmare to fly. After 35 hours of flight time and the cancellation of the Arrow, the B-47 testbed was returned to the US, who scrapped it immediately. Legend has it that the off-axis thrust from the Iroquois irreparably warped the frame.

 

[Scott Kenny]

You may have already seen this at http://www.aerospaceprojectsreview.com/blog/?p=872




Attached is a picture of what looks like radiation doses around the nuclear engine. My quick conversion gives me 1000 Gy/hr in zone I and 5 Gy/hr in zone VIII. Could somebody knowledgeable check these numbers, because they look very very high, even for the 60s.

Yes, my math also says 1000Grays/hr in Zone 1 and 5 Grays/hr in Zone 8 at the cockpit. 1 erg is 10^-7 Joules per gram, and 1 Gray is 1 joule per kg, so 10^7 ergs in Zone 1 is 1 joule per gram, making 1000grays/hr...

Which is probably why this was cancelled. Sweet merciful Christ, that exposure!!!! For people who are more familiar with rems, 1 rad/rem is 1/100 gray, which means that they'd be exposed to 500rem per hour in the cockpit!

500rem/hr is 100x the 2023 annual limit for nuclear workers, and is still 33x the annual limit from the late 1950s. Per hour. That's not a "no", that's an "oh, hell f*ing NO!!!" level of exposure. Even if we assumed that the exposure is pure X-rays, the permissible exposure limit dating all the way back to the 1930s for X-rays alone is 50 rem/year. (source: https://www.nrc.gov/docs/ML0504/ML050400427.pdf pages 4 and 5)

 

[Ravinoff]

Yes, my math also says 1000Grays/hr in Zone 1 and 5 Grays/hr in Zone 8 at the cockpit. 1 erg is 10^-7 Joules per gram, and 1 Gray is 1 joule per kg, so 10^7 ergs in Zone 1 is 1 joule per gram, making 1000grays/hr...

Which is probably why this was cancelled. Sweet merciful Christ, that exposure!!!! For people who are more familiar with rems, 1 rad/rem is 1/100 gray, which means that they'd be exposed to 500rem per hour in the cockpit!

500rem/hr is 100x the 2023 annual limit for nuclear workers, and is still 33x the annual limit from the late 1950s. Per hour. That's not a "no", that's an "oh, hell f*ing NO!!!" level of exposure. Even if we assumed that the exposure is pure X-rays, the permissible exposure limit dating all the way back to the 1930s for X-rays alone is 50 rem/year. (source: https://www.nrc.gov/docs/ML0504/ML050400427.pdf pages 4 and 5)

That's all assuming an unshielded cabin, yes? It's probably safe to assume modifications would be done to prevent lethally irradiating the crew. The NB-36H flying reactor testbed used a massive 11-ton shielded cockpit module with lead and rubber lining and lead-glass windows up to 12" thick. What exactly the Soviets used on their equivalent Tu-95LAL isn't entirely clear (the wiki page is confusing and I don't read Russian), but there are mentions of steel plating and cadmium.

 

[Scott Kenny]

That's all assuming an unshielded cabin, yes? It's probably safe to assume modifications would be done to prevent lethally irradiating the crew. The NB-36H flying reactor testbed used a massive 11-ton shielded cockpit module with lead and rubber lining and lead-glass windows up to 12" thick. What exactly the Soviets used on their equivalent Tu-95LAL isn't entirely clear (the wiki page is confusing and I don't read Russian), but there are mentions of steel plating and cadmium.

View attachment 706093

You'd need twice the tenth-value shielding thickness to make that any form of safe, and while that reactor was hot no ground crew could get near the plane even approaching from the front.

Edit: two tenth-value shielding thicknesses is somewhere in the neighborhood of 44+mm of lead to stop the gamma and xray exposure, plus whatever neutron barriers you like.