Sunday being a day of rest, and my brain being full at the moment and wanting a break from stuffing in new languages and libraries, I took a stroll down memory lane, in a nuclear explosive jet powered EOTWAWKI kind of way… 12 minutes about a big ass missile that could cruise for weeks or months, fly at mach 2 to 3, fly at 100 m off the ground, drop multiple nuclear warheads, and then use the remaining fuel to commit long term “area denial” via radioactive exhaust plume, if desired.
By Curious Droid, who does a whole lot of interesting aviation themed videos.
Seems we decided not to make one partly due to the Bay Of Pigs almost destroying the world “issue”, well, that, and realizing it was a Very Dangerous Thing to actually make…
Yet they DID make and test the engine. Had a compressed air ‘tank’ at 3600 ish PSI that could deliver 545 tons of air in 1.5 minutes to the air intake of an engine the size of a train locomotive. AND did so. (Actually, that tonnage was for the smaller test engine, per the final test, all the video says is that it was an expanded air supply and ran for a few minutes…)
Ah, back when playing with really big really fun “toys” was something America just loved to do… the “Can Do” generation ;-)
I especially like the bits where they show someone loading the fuel pellets by hand… and the part where guys are standing around a reactor they are assembling in plain old street clothes. But hey, it was a “ceramic reactor” running a a few thousand PSI and several hundred degrees C, so why worry?
The idea of a 50 MW (or 500 MW) reactor you can put in a modest rail car (or a large one) is just sooo 1960s ;-) Wonder if the folks in Australia could use a 1/2 GW of power on a rail car to put near places needing some extra? Yeah, you would need to add a boiler, but hey, that’s just some pipes ;-) Or Canada (and Chicago) where they could just use the heat directly to warm up! ;-)
Gives you a whole new perspective on the power in “nuclear power”.
Musings from the Chiefio 
Some of those reactor core design features also ended up in the Ft St. Vrain High Temperture Gas Cooled reactor here in Colorado. The fuel for it was composed of ceramic coated pellets, and they were moderated by hexagonal graphite blocks, which were all nested together to form the core, then the system once critical was cooled by high pressure helium.
They mentioned in that video that one of the features of that design was that the fuel elements were small pieces able to move a bit to prevent stress build up as it heated.
Well that sort of behavior was one of the issues with Ft. St. Vrain the graphite blocks were free to move slightly and as I understand it, this caused small changes in energy output as the core adjusted to heat expansion and contraction on cooling. In effect the changing geometry of the core was doing a bit of independent control on power output as the core elements shifted slightly.
(see lucy locks in this link)
http://www.fsvfolks.org/FSVHistory.html
The primary reason for shutdown however was other issues with corrosion and poor maintenance processes, and lack of reserve capacity on some engineering elements (water control). (classic case of scientists and MBA’s not wanting to listen to engineers)
The fuel however was pretty unique being a mixture of Uranium and Thorium
source : https://lynceans.org/tag/fort-st-vrain/
Fort St. Vrain (1976 – 1989)
330 MWe General Atomics HTGR operated in Colorado
Used highly-enriched 235U / thorium fuel in the form of TRISO and BISO microspheres coated with pyrolytic carbon, which were embedded in a graphite matrix and placed in prismatic graphite fuel elements. The TRISO fuel particles were highly-enriched 235U and the BISO fuel particles were thorium.
Almost 25 tonnes (25,000 kg, 55,155 pounds) of thorium was used in fuel for the reactor.
https://en.wikipedia.org/wiki/Fort_St._Vrain_Generating_Station
http://ansnuclearcafe.org/2018/02/06/fort-st-vrain-in-pictures-1/#sthash.lKvcO7CX.dpbs
http://ansnuclearcafe.org/2018/02/14/fort-st-vrain-in-pictures-2/#sthash.5HwxhcaM.dpbs
The concrete containment vessel was also a unique one piece design, it was poured in a single pour, they placed washed aggregate in the forms then pumped high pressure cement in from the bottom so it gradually filled the forms from the bottom up pushing out trapped air.
Larry
IIRC the pre-stressing rods were wound so tight that, in the event of an over-pressure within the dome, it would part, relieve pressure, and then reseal
Atomic reactors are not so well suited to make electricity, but a lot of places you could use the heat directly. I wonder how many reactors there exist jus to make heat?
Tom Lehrer recommended staying indoors when Santa’s reindeer were flying by. Can you imagine how much worse it will be with flying nuclear reactors?
Fortunately Uncle Sam is made of sterner stuff than you or I so a nuclear jet engine project was undertaken:
https://en.wikipedia.org/wiki/Aircraft_Nuclear_Propulsion
Somehow common sense prevailed but the idea of a lightweight reactor survived at ORNL:
Just a tidbit of personal data, but during the most recent solar eclipse near me, I visited Oak Ridge, TN. My mom’s younger brother lives there. He is the only one left now of that generation. While there, I visited part of the ORNL. It doesn’t look like much … but, oh, what a history.
I am doing some reminiscing as I was in the hospital recently. That is one of the lesser points to getting older.
@CDQuarles:
Looking at places where that era of history were made is an enlightening thing. So much accomplished with so little. Look at Bletchley Park where the code breakers worked. From link in:
https://en.wikipedia.org/wiki/Bletchley_Park
One big old ornate house / mansion.
Looks like it’s a techno-geek tourist spot now:
https://www.bletchleypark.org.uk/
I want to go see the fused glass at ground zero of the first atom bomb test, but it’s way out in the middle of nowhere… and from the photos I’ve seen it is one monument stele and a flat bunch of dirt. (Everything else being vaporized in the BOOM! ;-)
But there is something about standing in those modest places and realizing it really doesn’t take much… just determined people who can think well.
Hopefully your hospital issues will resolve well and soon…
When I was doing some radiological response training they sent us out the Mercury Nevada test site, I got to stand on the rim of the Sedan shot crater and down on Frenchman Flats and walk around some of the test structures that they used, and do some actual radiological monitoring on an area where they intentionally set off devices that would not work right to see what would happen in a plane crash where the symmetrical implosion shell did not fully detonate.
Very humbling to stand there looking a rail road trestle that was badly distorted by the blast wave, or the bank vault near ground zero where the blast stripped off the corners of the reinforced concrete shell, and laid the large diameter rebar back against the side of the vault like wet hair stuck to your forehead.
I would also like to go to trinity site but I understand it is only open once a year in the spring, but it is much closer for me than for you.
For those interested:
Trinity Site Open House
April 6, 2019 and October 5, 2019
The first Saturday in April and October.
Stallion Gate Hours: 8 a.m. – 2 p.m.
Trinity site closes promptly at 3:30 p.m.
This event is free and open to the public. No reservations are required.
For more details click on the information links/short videos below
or contact the WSMR Public Affairs Office at 575-678-1134.
https://www.wsmr.army.mil/Trinity/Pages/Home.aspx
@Larry Ledwick,
“Very humbling to stand there looking a rail road trestle that was badly distorted by the blast wave, or the bank vault near ground zero where the blast stripped off the corners of the reinforced concrete shell, and laid the large diameter rebar back against the side of the vault like wet hair stuck to your forehead.”
The effects close to a nuclear blast are mind numbing. However it is amazing how close you can get to a nuclear blast and survive. I was responsible for ABC (Atomic, Bacterial and Chemical) precautions in my regiment in 1958. We were operating Centurion Mk 7 tanks so we wanted to know our chances of survival if subjected to nuclear attack.
According to data from 20 kilo-tonne weapon tests in Australia a Centurion tank at 400 meters from “Ground Zero” would literally be blown away. The crew would be beaten to death as the tanked rolled over and over. At 800 meters the tank would remain upright but would lose all external bins, hull mounted weapons and antennae. The crew would survive but would suffer radiation sickness. An infantry man could survive at a distance of 1,000 meters if he had at least one foot of soil or concrete to shield him from radiation.
@gallopingcamel: Thank you. A bit of real-life perspective. No modeling there. Where did risking it all for true knowledge and understanding go?
Ah… averages… “The average nuclear blast will… ” (choke 😆 choke 😆😆, choke 😆)
P.S. Remind me to buy a tank instead of an EV for my next car….. ya never know…😜
@G.C.: So that backyard bomb shelter would work!
Guess I need to start digging a trench for some corrigated pipe… :-)
Albeit I have not viewed the vault item, I have build many vaults. Those would be #5 rebar and vary in layers/density along with concrete thickness and compression strength, based on old standards per US Bank Protection Act. That would be a place to hide if needed, as long as you can open the vault door. Just sayin.
@ossqss – Regardless of the era, anyone who didn’t consider eventually surviving the unsurvivablie, (Frenche pronunciation
This is the vault.
https://www.atlasobscura.com/places/atomic-bank-vault
Interesting side story, after this shot they pulled the vault door off and used it to plug a horizontal tunnel that they used for another test. In that test the bank vault door was shot across the valley like giant iron spitwad.
Location of the vault is here 36.7984 -115.9337, but looks like the map images of the test site are resolution reduced to blur detail. Image is not near as detailed as other satellite map images (no big surprise really given the nature of the work that happens there to this day)
I can pick one other test item that was near the vault, they had some hemispherical aluminum dome shelters just a little closer to the shot. The one closest to the vault was not damaged, but closer domes were crushed down into their foundation on the side facing the blast. As I recall the metal in those domes was about 1/2 inch thick aluminum.
Based on ground features looks like the shot tower was at
36.7984 -115.9337
The vault is about 1/2 mile from the shot tower location. According to the nuclear weapons effects calculator that means overpressure was about 17 psi. They generally consider 10 psi will totally destroy all but reinforced concrete buildings, so that sounds about right.
It looks like the outside was eroded by the debris rocketing past, overpressure not so much…
IMHO, the big takeaway from Hiroshima was not how many were killed, but just how many survived. I’d thought the place would be just gone and all the people with it. Turns out a lot of folks lived, even if under the rubble for a while.
Since the explosive force is radiating into a hemisphere, it fades rapidly with distance. While you will lose windows a long long ways away, it isn’t that hard to survive in anything sturdy at modest distances. “Somewhere” I have a book with graphs of overpressure vs distance. While buying our house (during USSR days…) I wanted to be far enough from probable “ground zero” points that the house would be damaged and likely a loss, but the people inside would survive. I’m right at the edge… But now the main target (Moffett Air Station) is no longer a target, but a Google Playground.
My best determination was that if a sub launched nuke went off over Moffett, we would survive and be able to get in the car and “bug out” before the fallout got here; and be far enough down the road to not be done in when the 50 Mt big boomer came over from Muh Russia… Assuming the sub launched nuke was in fact a small one….
At the time, however, IF the attack came while I was at work, I would have been toast. It would have been spouse and kids doing the bug-out. Work was at Apple in Cupertino about 6 miles away… In theory I could survive a sub launch of a small one IF I was inside one of the cement wall buildings (likely minus ear drums as the windows blew in) BUT I’d not be able to go anywhere before The Big One came over the top…
We just knew Moffett would be hit as that was where the P3 Orion Sub Hunters lived… They used to fly over every day. Our site was directly under their climb out from the runway… and in some wind conditions, their return home. What’s the first thing the sub would want to eliminate? Oh, yeah…
Ah, the joys of the Cold War…
Same here. The small city that I, for the most part, grew up in, had a munitions plant. We figured we’d be a ground zero and carried on. The old City Hall had a fallout shelter ;p, so good luck getting there. Drills were, mostly, hide under your desk at school. The munitions plant was a few blocks away, literally, more or less on the north side of the center of downtown; and not too far from the old city hall. We’re talking two air miles or so, tops, from that plant, to the edges.
The blast over pressure is doubled at the surface facing the blast as it gets reflected back (like a large wave hitting a breakwater. In an ideal altitude burst the blast wave over pressure is also doubled due to the formation of a “mach stem” as the shock wave bounces off the ground and reinforces itself, creating a near vertical wall of blast pressure double the free air over pressure. At 17 psi over pressure the momentary force on the front of the exposed concrete vault would have been at least 34 psi (4896 pounds per square foot as a hammer blow impact)
When this blast front arrives at a perpendicular surface, that over pressure again can reflect increasing the blast loading even more. The likely over pressure on the front face of the vault would have at a minimum been near 5000+ pounds per square foot and probably more.
There is a lot of secondary debris blasting, for sure, depending on what is up wind, but the major damage to large structures is due to that very fast front loading as the shock wave arrives. The differential loading also causes a strong push to the entire structure as the front face is exposed to the full reflected pressure, but the back side of the structure has not yet been enveloped by the shock front (this is most important to larger structures where the time lag between front loading and full envelopment is large) and then the dynamic aerodynamic loading of the blast winds both positive away from the detonation point and then a short time later by the weaker reverse flow winds back toward the blast site.
At a significant distance from ground zero you also create a precursor wave shock near the ground as the blast wave travels through air heated by the ground and the thermal effects of the fireball and runs out ahead of the main blast front close to the ground.
Different structure types respond to different phases of the blast wave, brittle structures like cinder block walls, windows and if close enough concrete gets shattered or broken by the initial shock front hammer blow. Roofs on residential structures respond to the lifting forces of the blast winds, especially if the shock wave blast loading has distorted the front wall enough to break the top wall roof anchors (in which case the front wall gets blown in, the roof lifted off and the side walls sheared away and pulled outward). On residences this often leaves just a core of the structure remaining while the outer walls are all blown down wind. The foundation anchors of the walls are most effected by the differential loading of the front / back wall as the entire structure tries to resist that lateral load.
Small dimension structures like phone poles are relatively insensitive to the shock front because the shock envelopment is so rapid, but are pulled over and broken by the dynamic wind forces just like in a hurricane due to aerodynamic drag.
Common homes have windows and door blown in at low pressures, windows start to break around 0.5 psi over pressure and doors and interior partitions can get blown in at 2.0 psi. Most common residential structures are uninhabitable and effectively destroyed at 5.0 psi, damaged but usable in the 2.0 – 3.5 psi range and strong industrial builds are destroyed at about 10 psi. At 30 psi the ground is pretty much swept clean.
The whole damage analysis of who nuclear weapons destroy structures is really fascinating.
Fun little comment on twitter:
Adam Townsend
@adamscrabble
Following @adamscrabble
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Sorry to disappoint folks, ‘green energy’ ain’t green, and it’s barely even energy.
You are a nuclear energy denier
That is not a typical vault. The door’s steel vestibule is not consistent with the newer rated construction methodologies over the decades following. Most vaults were minimum 12″ poured 3,000 PSi concrete until the emergence of UL listed/tested interlocking modular vault panel systems (class 2 or 3 typically 12k PSI chemically enhanced compression strenght) that cut down construction time to 1 day for a vault.
It has been a while since I was involved in constructing radiation shielding. IIRC the ABC manual from 60 years ago stated that it takes about 4″ of concrete to reduce the gamma flux by a factor of ten so one foot gives a 1,000:1 reduction. Two feet gives you 1,000,000 to one.
At the Duke FEL laboratory some of the gamma sources were much brighter than a 20 kilo-tonne bomb. The entire machine is encased in two foot thick concrete shielding and in critical places much more. For example at the end of our linac tunnel we have four feet of lead and ten feet of concrete. In spite of all that shielding, the area radiation monitors start squawking if the beam hits anything.
While that may sound impressive it is pitiful compared to the beam dump mountain at the Jefferson laboratory in Virginia which is over 100 feet high.
Go nuc yourself!
https://nuclearsecrecy.com/nukemap/
Fun (in a way) interactive map. Select your bomb from the list, Choose air or ground blast, acquire your target and bombs away!
@Quail,
Wow! Amazing. The acute LD50 dose for gamma rays is ~4.5 Sieverts.
The good news is that the LNT (Linear No Threshold) model is wrong. If you are subjected to 5 Sieverts spread over three months or more your health may improve.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2477708/
@Quail,
I entered a 20 kilo-tonne blast and it showed a “Radiation Radius” of 1,410 meters meaning that the flux exceeds 500 REM. REM (Roentgen Equivalent in Man) has been replaced by the Sievert (one Sievert equals 100 REM). This is consistent with my assertion that the LD50 dose of gamma rays is ~5 Sieverts.
Sixty years ago the British Army told me that the crew of a Centurion tank at 800 meters from ground zero of a 20 kilo-tonne nuclear blast would survive. At 800 meters the gamma flux would be (1,410/800)^2 times 5 Sieverts = 15.5 Sieverts with no radiation shielding.
While a Centurion tank has about eight inches of steel shielding in the horizontal plane, there is only two inches of shielding in the vertical plane. Given that the optimum altitude for a 20 kilo-tonne air blast is 600 meters, the effective shielding for a Centurion tank 800 meters from ground zero is equivalent to 2.7 inches of steel. The corresponding attenuation of gamma rays would be about a factor of ten (similar to four inches of concrete).
Thus the acute radiation dose inside the tank would be about 1.5 Sieverts. The onset of radiation effects are sudden by which I mean that an acute dose of 1 Sievert is unlikely to cause noticeable symptoms while a dose that is five times larger will kill 50% of affected individuals.
Thus it seems that the British Army was telling me the truth sixty years ago when they said that at 800 meters a tank crew would suffer from radiation sickness but would have a better than 50% chance of survival.
Well technically that 450 rem (4.5 Sievert) dose is supposed to be LD50 /30 [death within 30 days].
Although sickness might show up within hours final organ collapse or death due to secondary infection would likely occur a couple weeks later.
As I recall for immediate incapacitation you need absorbed doses up above 1000 rem (10 S) but like you I have not worked with radiation exposure limits for a long long time.
One worker was exposed to 4500 cGy (4500 rad) in a prompt exposure and was able to shut off his equipment and run from the building and briefly talk with coworkers but within minutes was incapacitated.
The problem with radiation injury is it is not a simple relationship. High dose prompt radiation causes immediate sickness and incapacitation followed by a brief recovery period than later total incapacitation as the long term effects take over. The other issue is that radiation effects are statistical you can only reliably talk about what dose will incapacitate a percentage of a large group exposed to that absorbed dose. There will be a few individuals which will defy the charts predictions.
Click to access a273213.pdf