Streetwise Professor

August 20, 2019

I Call BS on the Russian Explanation for the Severodvinsk Explosion: I’m Sure You’re Shocked

Filed under: Military,Russia — cpirrong @ 2:30 pm

Note: I wrote this Saturday, but was unable to post because of a technical problem at the site. No doubt those damned Russkies were trying to silence me 😛 I’ve only made slight edits, and added the part about Norwegian detection of iodine. Some of what is posted here anticipated discussions in the comments on Sunday and Monday.

In my original post on the Severodvinsk explosion I expressed puzzlement at the Russian explanation that they were testing an “isotope power source for a liquid-fueled rocket engine.”  I did some research to address my ignorance, and found, indeed, that radioisotope rocket engines are a thing.  The problem is that this thing is inconsistent with the closure of nearby waters due to the presence of toxic rocket fuel (allegedly from the explosion) and the mention of “liquid rocket fuel” in the explanation.

Radioisotope rocket engines work by using the energy released from the decay of radioactive isotopes to heat a solid material (the “capacitor”).*  When the capacitor is sufficiently hot, fuel is passed over it.  The capacitor heats the fuel.  The hot gas is vented out through a shaped nozzle, which accelerates it (exploiting the Venturi Effect), creating thrust.

The motor generates a greater pulse (the thrust produced with respect to the amount of propellant exhausted per unit time) than the Space Shuttle Main Engines.  But it generates far less power.  Further, it is fuel limited, and thus does require fuel which limits its utility as a source of continuous propulsion.  Thus, its main application is as rocket thrusters in space, not launching projectiles or powering aircraft or missiles in the atmosphere.  All of the applications of this source of power that I have seen relate to space in some way.

But here’s the thing: whereas conventional rocket engines operate by combustion (i.e., stored chemical energy is released as the result of the burning of the rocket fuel) radioisotope rockets do not.  The fuel is not burned, just heated. Hydrogen has advantages and disadvantages as a fuel for such rockets, but crucially there is no need for conventional rocket fuel, which is nasty stuff—toxic when it isn’t blowing up.

Which is why I call bullshit on the Russian story that specifically mentions “a liquid-fueled rocket engine.”  Conventional liquid rocket fuel combusts—big time.  Even if the Russians were to say that the liquid fuel was liquid hydrogen, that would not explain the alleged release of toxic rocket fuel in quantities sufficient to require the closure of beaches and fishing areas.  And why wouldn’t the Russians say it was a hydrogen explosion? The huge explosion also suggests highly explosive rocket fuel. 

Put simply: a radioisotope propulsion system cannot explain a release of radiation and toxic, combustible liquid rocket fuel. An explosion of a Petrel, or something like it can. The Petrel needs a rocket booster, and hence rocket fuel. The missile’s ramjet is powered by a nuclear reactor.

The Norwegians also reported they detected a release of radioactive iodine. This is consistent with the destruction of a reactor with a fissile fuel source, but not with the explosion of a radioisotope propelled vehicle.

One last thing cements my suspicions.  In their move along, nothing to see here explanation, the Russians said that NASA has developed an isotope power source (“Kilopower”).  Yes, Kilopower is a low power (1kW, with plans to go to 10kW) engine intended to generate electricity for spacecraft. (No rocket fuel, or any fuel for that matter, required!)  So it is almost impossible to imagine it, or anything remotely like it, blowing up, or even being around anything that would blow up, as happened in Severodvinsk. 

But “the Americans do it!” is an excuse right out of the old Soviet playbook. It is a convenient cover story, and one used repeatedly in the past.  Which suggests that they have something the Americans are not doing to cover up.  When this is added to the glaring inconsistency involving rocket fuel and radioisotope rocket engines, the circumstantial case that a Petrel/Skyfall accident is to blame for Severodvinsk becomes very strong indeed.

*It is sickly amusing to note that although the most commonly mentioned power source is Plutonium, Polonium (of Litvinenko infamy) has also been suggested.

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1 Comment »

  1. The US version of the RTG or radioisotope is called the ‘poodle’ rocket. We have tested it, we have developed a few of them for the purpose of nearly unlimited deep space thrusters. The main idea of the poodle rocket is an ever-accelerating ship, which is launch away from the center of the galaxy. It truly would be ‘where no man has gone before’ and it would continue to accelerate as the poodle rocket once activated has no known means of throttling. This is just an application of Newtonian law, and won’t change. As noted, first there is no ‘liquid’. It’s just a stream of radiation, ever expanding. It’s pretty clear I think that this was some well-known nominal rocketry with a liquid or slurry propellant that simply got away from therm. The resulting chemical explosion was really bad, and damaged the second stage which was the heat source(reactor core) ‘aloft’ ramjet, a second or maybe third gen design of a combined HTRE and Pluto. Since it asploded, I don’t think we’ll ever know if it was a direct air cycle motor, or if it was designed with an exchange process in between, and then to drive a simple compressor stage with resultant fan blades out front – just like a modern turbo-fan jet engine.

    I’m going to speculate that for lack of leaving a nasty trail of radiation behind, it was more compressor-like, and less actual ‘ram’ jet like. Although it would be heavier to design and build, the gas technology, and metallurgy is pretty well developed. The air cycle direct ram jet is not something that I would think hold up for more than a few weeks at moderate power. The engine basically is a sacrificial slow-burn process. What’s more, when the ship is done – maybe 2-15 months down the road, they can’t just land it, and go over and la-de-da start disassembly. It’s going to be so hot with radiation it’ll be contaminated for centuries. Maybe they planned to just fly it over the Philippine trench, aim it vertical and sink the nasty glowing detritus. Gulp…

    Comment by doc — August 21, 2019 @ 12:18 am

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