America's fastest locomotive

M-497, nicknamed "The Black Beetle".  This was the fastest locomotive to operate in the US.  It was an experimental locomotive build and tested by the New York Central Railroad.  The locomotive was actually a Budd Rail Diesel Car (RDC-3) powered by two second-hand GE J47-19 turbojet engines. These engines had originally been mounted on a B-36D Peacemaker for take-off assist and dash speed over the bombing target.  The B-36 was active from 1946 to 1959

Below:  B-36 Peacemaker.  Note the outboard engines are a pair of turbojets...

Below is a photo of a Budd Rail Diesel Car.  These were individually powered rail cars, i.e. passenger or mail coaches that also contained two small diesel engines.  These single cars were used in rural areas where passenger traffic was light.  Photo courtesy of Bevis R. W. King.

Below is a photo of our hybrid of the Budd Rail Diesel Car and the B-36 turbojets.  The M-497 in 1966, with the B-36 engines mounted up front.  An aerodynamic nose was added to the locomotive, and the diesel engines were removed.

M-497 on one of the test runs, which took place between Butler, Indiana and Stryker, Ohio.

Another picture of M-497, clearly moving at high speed.

This testing was done on straight track in good condition and with no modifications.  The top speed was measured at 183.68 mph - a record that was set in 1966, and which unfortunately has not been broken since in the US.  A passenger train going that fast would certainly be awesome.  I'm pretty sure it could be done....

Steam Turbine Outage

This may or may not be an interesting topic to the random readers that drop by here.  I honestly don't know.  I've been around steam turbines my entire adult life, and have never given the shaft sealing system much thought - until we had a seal failure that ended up with the accumulation of a bit of new knowledge, which I share here.

As you would guess, steam tends to leak out of a steam turbine at the high pressure end, where steam enters the turbine, and air tends to leak in at the exhaust, where the final stage of the turbine is at 1-3 inHg Absolute pressure (25-27 inHg vacuum).  Steam turbines are not sealed like pumps.  Pumps use flexible packing or mechanical seals, that actually come in contact with the shaft.  Steam turbines do not seal this way, due to large swings in operating temperature from cold to running.  Instead turbines are sealed using steam!

I took a quite a few photos while the steam turbine was apart for the seal repair, and thought they were interesting enough to put up.  The steam turbine is a General Electric model A-10.

Most modern steam turbines are what we call "self-sealing".  What that means is that they only need to be supplied with sealing steam during startup and shutdown.  After the turbine reaches a certain load (5-20%), leak-off from the turbine supplies the seal steam, and external sources can be shut down.  If there is any excess leak-off, and the seal steam supply pressure gets above the setpoint, a seal steam dump valve opens, and dumps the excess steam into the main condenser.

The symptoms of a failed steam sealing system are these:  

• The seal steam dump valve is 100% open, and yet the seal steam header pressure is still too high.
• Water vapor and condensation coming from the Lube Oil System vents.  
• Increasing Lube Oil Tank level due to steam ingress and water contamination/condensation.
  

Note:  Water enters the lube oil system because the turbine shell is very close to the bearing housing.  So as steam leaks out along the shaft of the turbine, it can leak right into the adjacent bearing housing.  The lube oil system is kept under a light vacuum so that air will leak into the bearing housings, rather than oil leaking out.  This will help pull in steam if the steam seal is leaking.

First of all, before any work can begin, the steam turbine must be shut down and allowed to cool.

Following the shutdown, the steam turbine has to be continuously rolled at low speed (typically 4-10 RPM) for about 3 days.  Steam turbines operate at very high steam pressures and temperatures, and as a result, the turbine shell is very thick at the high pressure end.  The shell is also insulated for thermal efficiency as well as for safety.  For these reasons it takes several days before the turbine is cool enough to stop turning.

The purpose of rolling the turbine is to prevent warping the rotor.  If the rotor is allowed to stop, it will develop a bow.  Once a bow develops, it may sometimes work itself out when the steam turbine is returned to service; the rotor, reheated by steam, becomes ductile again and the bow mostly disappears.  Other times, with severe bowing, the machine cannot even be started due to increased vibration caused by the off-center mass of the rotor.  The damaged rotor will require machining and the addition of balance weights to compensate for the bowing, if not complete replacement.  Needles to say, it's preferable to keep the steam turbine on the turning gear until it cools down.

Interestingly, a steam turbine rotor does not sag if it cannot be rolled during cooldown.  Instead it humps up in the middle, because of the temperature differential between the top and bottom of the turbine shell.  It is not unusual to have a 200 degree temperature differential between the top of the shell and the bottom.  As heat rises inside the shell, the bottom part of a motionless rotor will contract more quickly than the top, which then bows the rotor upwards.

Onward now to the bits and pieces of a smallish high pressure steam turbine outage...

Below, a worker uses a sledge hammer to remove a nut from a through-bolt on the high pressure turbine shell.

Just above the worker's hard hat, is a black bundle of tubes.  This bundle is the power supply for an inductive heater.  The inductive heater fits down inside the through-bolt (which is hollow), and heats it up.  As the bolt heats up, it stretches out, making it much easier to remove the nut.  The same thing takes place during installation, except when the bolt cools, it shrinks, which draw the upper and lower half of the turbine shell very tightly together.  Note the insulating blanket on top of the shell.  Workers didn't want their feet to get burned while removing auxiliary piping.

Below: The top of the High Pressure turbine shell.  The far end (burnt off paint) is the high pressure steam inlet.

Below, two workers removing the high pressure inlet steam seals.

Below: Another image of the high pressure turbine.  At the bottom left corner on the rotor, are holes for balance weights.  Next is the steam sealing section, then a series of discs with tiny blades at the end.  These discs are the 10 stages of the high pressure steam turbine.  The generator is the big thing to the right.  Notice how thick the steam turbine shell is - This is why it takes three days to cool the steam turbine down from 1050 degrees F.

This is a close-up of the high pressure steam sealing section, with the packing (or labyrinth seals) removed.  High pressure (up to 1800 psi) steam enters the turbine just to the left of the disk on the right hand side, and then flows off to the right. At 1800 PSI, steam would tend to leak out along the shaft and be a hazard for everyone around, as well as causing a loss of efficiency.  To prevent this, steam turbines use labyrinth seals.

Below: Side view of a labyrinth seal.  These segments slide into the grooves in the sealing section of the shell, sitting very close to, but not rubbing on the rotor.  The purpose is to make the steam pass through a "labyrinth", or a series of very tight passages, losing a little pressure with each ridge.  At the left end of the seal in the photo above, a small fan draws off the tiny amount of leak-off steam and condenses it for re-use.  Clever!

Below, labyrinth seals (or packing) installed in the grooves on the high pressure turbine.  Interestingly these are held in place by springs that are merely short flat pieces of steel These springs press against the inside of the packing gland and the outside of the labyrinth seal.  Several of these springs were found to be broken during this outage.

The picture below shows a part of the steam turbine that is contained within the lube oil system.  At the right is a journal bearing.  This supports the aft end of the high pressure turbine (which is just off the picture to the right).  You can see a wire coming off this journal bearing, which is used to transmit the temperature of the bearing metal.  To the left of the bearing is a flat metal flange on the shaft.  This is used to determine rotor expansion.  The shaft expands quite a bit as the steam turbine goes from a cold condition to the normal operating temperature of 1050 degrees F.  The coil of blue wire connects the rotor expansion position sensor to the monitoring system. The big gear is for rolling the rotor when the steam turbine is not in operation.  The big round flange with all the holes in it is the coupling which connects the generator to the turbine.

Below, the bearings at the other end of the high pressure steam turbine.  In the center is a journal bearing, with thrust bearings to either side.  The journal bearing supports the shaft, and keeps it from moving in a radial (side to side or up and down) direction.  The purpose of the thrust bearing is to keep the shaft from moving axially (left to right) .  The shiny flanges with no holes in them are a part of the rotor called thrust collars.  The shiny things just inside them are the thrust bearings.  This section of the steam turbine is continuously supplied with oil to cool and lubricate the components.

One of the pads from the old thrust bearing... not in very good shape at all.

These looked in pretty bad shape as well.  Obviously there had been some heating and breakdown of the oil into carbon deposits.

Replacement labyrinth seals installed on the high pressure turbine lower half.  Note the serpentine path that leak-off steam must travel.

High pressure steam turbine back together and being fitted with brand new insulating blankets.

One of the things you run into while starting a cold steam turbine is rotor growth.  The rotor does not contain as much material as the turbine shell, and it is completely surrounded by steam (although the steam temperature is kept as low as possible during start up).  At the same time, the turbine shell is also cold, but only has steam warming the inside of a *very* thick piece of steel.  As a result, the rotor heats up much more quickly than the turbine shell, and it therefore expands much more rapidly.

Because one end of the rotor is held in place by the thrust bearing, the other end of the rotor grows as steam heats it.  It's quite possible to have rubs if the expansion of the rotor gets too far ahead of the shell.  That's why you will find rotor expansion proximitors (Below). These little pucks monitor exactly how much the rotor has expanded.

This is one of the few outages I have had time to take pictures and learn a few things, because on scheduled outages, I usually have assignments that keep me too busy for that.  Was fun to learn, fun to share.

NOTE: There is a continuation to this post with some further useful information HERE.

Heating the shop: Step 1

The house we purchased recently has a really nice shop.  The shop is 40ft x 40ft, with a 13 foot ceiling.  It is insulated, has a tall insulated roll-up door, and is wired for 230V throughout.  It even has a small bathroom with a deep sink.  The bathroom is wired and plumbed for a hot water heater, but one was never installed.

The shop has a massive work bench with overhead lighting, and a large mezzanine area for storing stuff that you might not want cluttering up the main floor.  It has windows up high on two sides to bring in natural light.  In short, it's a really nice building!

What the shop doesn't have right now is heat, and that makes it unpleasant and impractical to use for several months of the year.  It also makes the diesel tractor very difficult to start.  The previous owner used the shop as a business, and because he was out there every day, he heated the building with a wood stove. There is a penetration in one wall where the duct for the wood stove once passed through.

I like the idea heating the shop with a wood stove for a couple of reasons:

1. I have plenty of dead trees available for fuel, and many more living ones that I need to clear for fire safety reasons.  
2. All of these trees are free.  

However there are a couple of very solid reasons that have convinced me not to install one:

1. My homeowner's insurance will go up, because wood stoves tend to be fire hazards.
2. Inconsistent temperature control, because I won't be using the shop every day.

Inconsistent temperature control is really THE issue.  When we bought the house, it was unoccupied, and a company had "winterized" the plumbing, filling all the water supply lines with an environmentally-friendly anti-freeze.  The shop still has antifreeze in the water supply to keep the pipes from bursting during the winter months.  I would like to be able turn on the water supply again and use the toilet and the deep sink, and to finally install that hot water heater.

If I were to install a wood stove, I would need to maintain a fire all winter in the shop to keep the temperature above freezing, or risk burst pipes.  Rather than have to deal with that, I thought it would be preferable to install a propane furnace with a thermostat to regulate the temperature.  I only want to keep the shop from freezing, and increase the temperature on those few times when I need to work there.

For the past couple of years I watched the Craigslist ads, and finally found what I was looking for.  In fact, the sellers were getting rid of two furnaces.  I purchased one, and a friend purchased the other. These units came from a logging company's maintenance building.  The logging company stopped using them because they got tired of paying the propane company for tank rental.  I intend to buy a small tank, so that won't be an issue for me.

My Craigslist treasure!  It even came with some exhaust duct and a cap.

The installed version, with horizontal ducting, should look something like this:

Not the same model heater, but you get the idea...

Next, I need to locate a 100 gallon propane tank.  This particular size is nice because the fire code allows you to put a fairly large tank right next to the building.  Anything larger would have to be 50ft away from the shop, which would necessitate digging a deep trench, running a lot of pipe, and having to rent the tank from the propane company.

This is the size that I have in mind (no that isn't me)

After that comes the infrastructure.  I will need to pour a slab for the tank, run some gas pipe, install the exhaust duct, add an electrical circuit for the heater, and install a thermostat.

I was a little concerned about finding a thermostat that has a temperature range as low as I need to go, but I located a digital garage thermostat that looks perfect for the task:

So, with a little time off (Heh. good luck with that!!!!) and some luck finding a propane tank, I may soon be playing...
in hot water,
in the deep sink,
in the shop :)

UPDATE:

I did get this project accomplished about 9 months later.  That post is HERE.

An interesting US submarine design

The previous post about the nearby, but not very effective or long-lasting Titan 1 missile launch complex reminded me of another early nuclear deterrent weapon system that didn't last too long. That weapon system was the combination of the Regulus missile with a submarine.  This was a weird combination of weapons that apparently made sense at the time...

The USS Grayback and USS Growler were commissioned as standard diesel-electric attack submarines in 1957, but were modified in 1958 with a watertight missile hangars on the front deck. This allowed the ships to carry either (4) Regulus 1 missiles, or (2) Regulus 2 missiles.  The result was not pretty.

USS Growler (SSG-577) surfaced and billowing diesel exhaust.

What was the purpose of these submarines and their aircraft hangars?  Once again, nuclear deterrence.  These ships were to stay submerged with their nuclear-tipped cruise missiles, and be prepared to fire them at the Soviet Union.  However if the command to attack were ever given, a ridiculous series of events would have to take place to launch a missile.

To perform a launch, these submarines would have to surface, open the watertight hangar door, and then slide the missile out backwards.  After that, the crew would unfold the wings and lock them in place, rotate the missile sideways so the exhaust wouldn't melt the ship, calibrate the missile's guidance system, (fuel the missile?), and launch it.

The missile also required radio control to reach its target, and two additional control stations were required along the missile's course.  It surely would have made for interesting times if the enemy were able to take control of the missile in flight!

Below, USS Grayback (SSG-574) rolls out a Regulus II missile in preparation for launch.

The missile used a solid fuel rocket booster to get it moving, and a GE J79 turbojet to fly at Mach 2 for about 1000 nautical miles, delivering a 2 Megaton W-27 thermonuclear warhead.

A nuclear-powered version of this submarine design was also built: The USS Halibut.  It had a slightly cleaner look, apparently having been designed around the missile bay, rather than having it tacked on after construction.

Below, USS Halibut (SSGN-587) launches a Regulus II cruise missile with attached rocket boosters.

These were not the first guided missile submarines however.  A previous generation of subs had carried Regulus I missiles, which had about half the range (500 nautical miles) of a Regulus II

Below, the USS Tunney launches a Regulus I cruise missile.

In the early cold war years, this arrangement was part of the strategic nuclear deterrent,  However the development of the vertically-launched Polaris Missile and the 16 tube George Washington class ballistic missile submarine rendered this entire design obsolete.

Within 10 years of the launch of the first ship, the last of them had been removed from service as missile carriers.  The Halibut was re-purposed as a special operations ship, and was decommissioned in 1976.

Duck and Cover: Children of the Cold War

Growing up, I can't recall a single instance of ever doing the "duck and cover" drill.

This lack of cold war education is a bit odd, because I grew up within a few miles of a nuclear missile launch complex.  The missile complex was taken out of service a few short years after it was built, while the US and USSR moved on to a paradigm of MAD, or Mutually Assured Destruction, so maybe the school board just assumed everyone on the planet would be vaporized by incoming nuke missiles.  In any event, I never performed a 'duck and cover' drill while at school.

I had heard rumors of the nearby missile complex when I was in high school, and it took a while after that before I could find someone who knew where it was located.  Boise, Idaho, where I grew up, is just off the top of the map below, and 569-C (near Orchard), is the nearby site I had a chance to explore.

Frankly it was a little intimidating driving up to the site, even with friends who had been there many times before.  It was fenced and posted "No Trespassing", and had various signs about being a felony to trespass, etc, etc.  The fence was in bad shape however, and the gate was askew. In we went...

In its heyday, the missile complex was part of the 569th Strategic Missile Squadron, based out of Mountain Home Air Force Base.  The missiles were deployed in a 3x3 arrangement - meaning three launch complexes with three missiles each.  Each of the above mapped "569" sites therefore would have three silos each containing a nuclear-tipped missile.

Below, a diagram of a three missile launch complex, showing the major components.  Note: Hydrazine was used on later missiles, so this likely a diagram for a Titan 2 missile complex.

The nearby launch complex was built around first-generation SM-68 Titan 1 missiles, and was only active for a very brief time before being superseded by more advanced missiles. The launch site was abandoned (rather than updated) at that time.  The 569th Strategic Missile Command was only active from June 1961 to April 1965 - a useful lifespan of under 4 years.  This must have been the only weapon system for nuclear deterrence with the longevity of a fruit fly.

Below, a Titan 1 missile, out of the silo.  Note the open blast doors and the Air Force markings.  This looks like it might be a commissioning ceremony, based on the contractor trailers and vehicles on site, as well as the tent adjacent to the silo.

The Titan 1 was the first true US intercontinental missile, having a range of 5500 nautical miles.  The arrangements required to launch the missiles were quite complex and time consuming, and this is very likely the reason that the system was abandoned so quickly, in addition to the rapid pace of rocket development in that era.

To begin with, the missile was a two-stage, liquid-fueled design.  The propellant was RP-1, essentially highly refined kerosene (a light oil) that was kept on board the missile.  The oxidizer, however, was liquid oxygen.  This had to be stored in an insulated and refrigerated cryogenic tank at the launch site, and pumped into tanks on board the missile immediately before launch, for both the first and second stages.

Further complicating matters, the silos were not designed with exhaust vents, so the blast doors had to be opened and the missile raised on an elevator out of the silo before launch could proceed.  There was no "quick launch" feature for this missile.  It took 15 minutes to launch the first one, and the other two would follow at 8 minute intervals.  Surely this would be an eternity in a nuclear exchange, particularly if you were not making the first strike.

The missile guidance system left a bit to be desired as well, being radio command.  Therefore this missile required radio signals from ground guidance to get where it was supposed to go.  The likelihood of intentional interference or Nuclear Electromagnetic Pulses (EMP) blocking this communication would be likely in the event of nuclear war.

What this missile could do however, was fling a W-38 thermonuclear weapon halfway around the globe and deliver a whopping 3.75 Megatons of destruction, with whatever level of accuracy the radio guidance system could provide.  Link to a Chinese video of a 3.3 Megaton airburst.

The missiles were pretty failure prone; of the 70 that were test launched, only 53 performed successfully - a success rate of about 76 percent.  That means that of two of the nine missiles from the 569th Strategic Missile Squadron probably wouldn't make it to the show - but those that did would make quite an impression ;)

And now, what you have been waiting for... the inside of the missile launch complex of the 1960s. (FYI: These are not photos that I took)

Below, a Google Earth image of the 569-C site near Boise.  The silos are to the upper left inside the fenced area.  The big pit in the center was dug to remove components from the complex when the site was abandoned.  It appears to be private property at this time.

This was how you got into the complex - where crews had dug down and made a ramp to remove the components from inside the control room.  The other option was to rappel down into the silo on a rope.  Being a little acrophobic, I chose the former.

Below, a lot of dislodged heating and cooling ducts, as well as some stripped down electrical cabinets.  Not sure what part of the complex this is...

Below is my favorite.  Take a look at the massive shock springs at the left and right.  All the critical equipment was suspended by springs - in event the silo had to deal with a nuclear first strike.  The *hope* was that an incoming nuke would not score a direct hit, and that the launch complex could survive to retaliate.  Modern guidance systems do not offer this hope of a near-miss.

Cool stuff!

Broken Arrows - USAF wins the trophy

"Broken Arrow" is the military term for an accidental event involving a nuclear weapon, but which does not create the risk for a nuclear war.  The 'accidental event' typically involves losing and/or damaging the weapon.

There have been 32 officially recognized "Broken Arrow" events in the United States since the dawn of nuclear weapons, as of Sept 2013.  Some of these events have been relatively minor, but others have been massive radiological accidents.  One accident with a large Hydrogen Bomb nearly made North Carolina uninhabitable... not that you would have seen THAT in the newspapers when it happened.  Apparently the news media were just as compliant in the 1950's as they are today.

I will go over a few of the more interesting Broken Arrow events.  Not surprisingly, most of these involve military aircraft crashing with weapons on board, as well as the intentional or inadvertent jettisoning of nuclear weapons.  All of these event descriptions are courtesy of Wikipedia.

Missing Radioactive Sources - Updated (23 August 2018)

This is a horrific and very sad story, but it seems like every year somebody attempts a repeat :(

***UPDATED 8-23-18***

OK, so I see we've lost another one - this time in Malaysia.  This one is an Iridium-192 source for industrial radiography.  I'm cackling about the statement from the authorities:

"It cannot fall into the wrong hands as the consequences can be deadly" 

You knucklehead.  It's already in the "wrong hands".  It's been in the wrong hands since the moment you lost custody of it.  The question we are left with right now is whether the "wrong hands" are (best case) thieves, or (worst case) terrorists.

It boggles the mind that such dangerous material gets stolen so easily.  If this were high explosives, or even just harmless money, there would be several armed guards constantly monitoring it, or it would be in a vault somewhere.  It's time to be much less stupid with such dangerous material.

I am the gamma ray shielding...

In any system filled with water, there will be corrosion.  It's inevitable.  Water is a highly polar molecule, and so it has a tendency to dissolve/corrode almost everything.  All you can do is attempt to minimize the amount of corrosion through careful chemistry control.  Even so, you will still get some corrosion.

In the primary coolant system of a nuclear reactor, what this means is that you will have a few (hopefully not many!) metal atoms suspended in the coolant.  These metal atoms will pass through the reactor core and absorb a neutron, and sometime become radioactive, depending on the metal.

Some components in the primary coolant system are made from Stellite, a Cobalt-Chromium alloy that has excellent wear and corrosion resistance.  Unfortunately even Stellite corrodes, and it also erodes over time due to wear.  For this reason there will always be some of these Cobalt, Chromium, and Iron atoms carried through the reactor core, suspended within the primary coolant.

The biggest nuisance among these metal atoms is Cobalt.  Cobalt-59 atoms that flake or corrode off the Stellite can absorb a neutron, and become radioactive Cobalt-60.  Co-60 has a half-life of 5.3 years, and decays by emitting two gamma rays at energies of 1.17 and 1.31 Million Electron Volts.

Eventually these now-radioactive atoms will find an eddy and come to rest in a low-flow point and settle out, much like silt behind a large dam in a river.  These low-turbulence points where the radioactive atoms settle out will now emit quite a bit of gamma radiation, due to internal contamination.  This stuff has a name: CRUD.

On the submarine, there were a number valves connected to the primary coolant system which were located outside of the reactor compartment, so that they could be opened or closed if necessary without having to go near the reactor.   One such system on the ship was for emergency cooling; if all electrical power were lost, we still had to be able to remove decay heat from the reactor core.

As a result of performing the required testing on this emergency cooling system over the years, several of the valves outside of the reactor compartment had accumulated a fair amount of CRUD in them - enough to deserve posting signage and discouraging loitering.

On to the story... one day in port, some routine maintenance inside the reactor compartment was being performed, and I was the control point watch.  That job meant I that I had to control access in and out of the reactor compartment, to ensure nothing bad happened to the guy in there, and to ensure he didn't bring any nasty radioactive crap out that was clinging to his suit.

To ensure the last, I had a very sensitive detector for sensing contamination.  It looked like this:
 
This meter is a Geiger type detector, with an attached "Pancake Probe".  The probe is heavily shielded on all sides but one, so that it will directionally detect radiation.  The open side has a thin mica window, protected from puncture by a mesh screen.  The radiation can pass through the mica and into the detector, which will provide a reading on the meter.  A selector knob allows you to choose a multiplier for the level of contamination you are dealing with, to keep the needle on-scale.  It reads out in counts/minute (times the multiplier).

Geiger-Mueller detectors work by maintaining a very high voltage across a low pressure gas.  This voltage is just slightly less than would be needed to cause all the gas to ionize and begin conducting continuously like a neon lamp. 

If a gamma ray or beta particle enters the tube, and reacts with a gas molecule, it will ionize it that molecule.  Next, the very high voltage immediately accelerates the positive and negative ions, causing them to bang into other atoms, ionizing them in turn.  Eventually the entire tube becomes ionized in a massive (but very brief) cascade, and you get one audible "click".  The gas in the Geiger tube immediately resets (because the voltage is slightly too low to keep the gas ionized) and the process repeats for every radiation event inside the tube.

I was sitting at control point, and got bored.  I decided to point the pancake probe (a very sensitive instrument for detecting minute amounts of contamination) directly at the CRUD-filled valves that were emitting a modest gamma radiation field.

The instrument went from clicking every second or so, to screaming.  I had place it on the highest range while pointing pancake probe at the internally contaminated valves, even from across the room.

Out of idle curiousity, I placed my body between the pancake probe and the valves, and the meter stopped screaming.  I was absorbing the gamma radiation that was making the meter swing!  On that day I shielded the sensitive probe from 10 mr/hr worth of gamma rays.  It was a little unnerving realizing that I was absorbing so much gamma radiation, just by being in the room with it. 

Meh.  I didn't even get an image for that exposure...

 

Radon - a radioactive hazard for everyone

Radon-222 is a radioactive gas that is heavier than air.  As such, it tends to settle at low points.  It is a "noble" gas, meaning that it doesn't react chemically all that much, because it has 8 electrons in the outer shell.  In this respect it is unlike Radium, which tends to mimic Calcium, and accumulate in bones, causing bone cancers.

Below is a diagram showing that Radon-222 is element 86 (has 86 protons), has 136 neutrons, and 86 electrons, with a full 8 in the outer shell, making it pretty much inert chemically.

Radon, although it is chemicall inert, and therefore doesn't bio-accumulate through a chemical process, is still extremely dangerous from a radioactive standpoint.  Radon is a type of "NORM", a.k.a. "Naturally Occurring Radioactive Material", and anyone can easily be receiving dangerous levels of radiation exposure without even realizing it.

Below is a diagram of the decay chain for U-238, and the portion that interests us begins in the middle, at Radon-222 (Rn).  There are several very damaging radioactive decays that will occur before a stable (non-radioactive) state is reached.  Thus one inhaled Radon atom can inflict biological damage over a series of radioactive decays.  All of these decays are internal, and therefore the alpha and beta particles are absorbed into living tissue inside the lung.

Uranium-238 at the top of our decay chain, tends to be more concentrated in granite than in other soils and rocks.  Below is a map showing the estimated prevalance of Radon-222 within the US.

Radon is particularly nasty because due to its density, it tends to accumulate in basements, where there is often little air circulation.  If an atom of Radon decays while in the lungs, it becomes a radioactive atom of lead, which is no longer a gas, and will therefore not be exhaled.  The radioactive particle will very likely stay in the lung.  Afterwards, the radioactive lead atom(s) will continue to decay in a series of events, damaging the DNA in the lungs.

Below are the some statistics on a variety of causes of deaths annually.  Clearly Radon is a hazard that should be taken very seriously.

Prior to moving into our new house, we requested a Radon test, and the result was 215 pCi/L (picoCuries per Liter).  The limit is 4 pCi/L.  The concentration of Radon in our basement was about 53 times the limit.

The biological damage inflicted by the radiation of 4.0 pCi/L of Radon (continuous exposure, annualized) is equal to the biological damage from 100 chest x-rays.

In equivalent biological damage for cigarettes, 4 pCi/L is equal to 10 cigarettes a day.  So the Radon in our basement had the biological damage equivalent to 530 cigarettes a day or 5300 chest X-Rays per year.  Not good.

The corrective measures for Radon however are pretty simple and inexpensive.  The basement (particularly penetrations for utilities) is sealed up, the dirt in the crawlspace is covered with a plastic liner.

A continuously-operating fan is installed that takes suction from underneath the liner and from underneath the floor in the basement.  This ensures any Radon will be swept away and vented before leaking into the house. 

After remediation, a follow-up test showed that our Radon levels had been reduced to 0.5 pCi/L, or about 1-1/4 cigarette per day, if you never leave the basement.  If I can live in Bakesfield air for 8 years, I can certainly deal with that! :)

Below, a Radon fan.  These come equipped with an alarm that sounds should the fan fail.

I highly recommend that anyone who has a basement have their home tested for Radon.  It's cheap. The test is definitely less expensive, painful, and deadly than getting lung cancer. 

Radium Girls

Radium is a naturally-occurring element with the atomic number 88 (has 88 protons and electrons).  All known isotopes of Radium are radioactive, and so eventually all Radium will decay into something that is stable, such as Barium or Lead. 

Radium is a metallic element in the decay chain of naturally occurring Uranium and Thorium, a transient state as these elements eventually decay into stable elements.  For this reason, there is no primordial Radium. 

Minute quantities of Radium are found in Uranium ore, and that Radium is transient, being radioactive.  There are four naturally-occurring isotopes of Radium, of which Ra-226 is the most abundant, due to its long-ish half-life of 1600 years.  That is, in 1600 years, half of the original Radium-226 will remain.  The other half of the original Radium-226 will have decayed in a series of radioactive decays into Lead-206, which is stable.

Below is a description of the decay chain of Radium-226: 
Radium-226 decays to Radon-222 after emitting an alpha particle (helium nucleus) and a gamma ray.  Radon-222 is also radioactive, and will decay to Polonium 218 by another alpha/gamma decay.  This in turn alpha/gamma decays to Lead-214, with a half life of 23 minutes, which beta/gamma decays to Bismuth-214.  This is also radioactive, (19m half life)  and beta/gamma decays to Polonium-214.  Polonium 214 has a VERY short half life (164 microseconds) and alpha/gamma decays to Lead-210, which is STILL radioactive.  The Lead-210 has a half life of 22 years and beta/gamma decays to Bismuth-210.  Bismuth-210 has a half-life of 5.5 days and beta/gamma decays to Polonium-210.  Polonium-210 has a half-life of 138 days, and alpha decays into Lead-206, which is non-radioactive.

The reason I went to the trouble of looking up and describing the Radium decay chain is to explain why this stuff is so nasty.  If you are exposed to a single Radium-226 atom, you could conceivably get 5 alpha particle events, 3 beta particle events, and and 8 gamma rays.  That's a lot of biological damage for a single radioactive atom.  Because of the decay chains embedded in Radium-226, it has a very high specific activity  (disintegrations per second).  In fact, the original measure of radioactivity, the Curie, is 3.7 x 10^10 disintegrations per second, was based on the activity of Radium (mostly Radium-226).  That is 37 Billion radioactive decays in a single second!!!

This gives Radium some really cool, if dangerous, properties.  For one thing, it glows faintly blue, due to ionization of the surrounding air by all those nuclear decays.  When mixed with a chemical compound that emits light when struck by radiation, Radium-226 can make awesome glow-in-the dark paint, that will glow brightly, for as long as anyone is alive.  Tritium, a far safer nuclide, is used in modern watches, but its half-life is only 12.3 years, so the brightness will noticeably fade in less than a decade.

Below is an image of a Radium painted watch dial.  I really would love to have one of these!!!

Radium, because of its high activity, and tendency to emit several alpha particles in part of a decay chain, is dangerous to be around, unsheilded.  Recall minimizing the biological damage of each type of radiation is mainly a matter of shielding and distance.  You have neither of these if you ingest radioactive substances.  Which brings us (finally) to the topic at hand, the Radium Girls.

The story of the Radium Girls is slowly passing into the mists of history, which is quite a shame.  These were young women hired by the U.S. Radium Corporation to paint watch and clock dials with a glow-in-the-dark paint.  This paint was made from Radium and Zinc Sulfide, and which went by the trade name "UnDark".

From the website "Damn Interesting", by Alan Bellows:

In 1922, a bank teller named Grace Fryer became concerned when her teeth began to loosen and fall out for no discernible reason. Her troubles were compounded when her jaw became swollen and inflamed, so she sought the assistance of a doctor in diagnosing the inexplicable symptoms. Using a primitive X-ray machine, the physician discovered serious bone decay, the likes of which he had never seen. Her jawbone was honeycombed with small holes, in a random pattern reminiscent of moth-eaten fabric.

As a series of doctors attempted to solve Grace's mysterious ailment, similar cases began to appear throughout her hometown of New Jersey. One dentist in particular took notice of the unusually high number of deteriorated jawbones among local women, and it took very little investigation to discover a common thread; all of the women had been employed by the same watch-painting factory at one time or another.

From here I will turn things over to Wiki:

Radium was formerly used in self-luminous paints for watches, nuclear panels, aircraft switches, clocks, and instrument dials. A typical self-luminous watch that uses radium paint contains around 1 microgram of radium. In the mid-1920s, a lawsuit was filed against the United States Radium Corporation by five dying "Radium Girl" dial painters who had painted radium-based luminous paint on the dials of watches and clocks.

The dial painters routinely licked their brushes to give them a fine point, thereby ingesting radium. Their exposure to radium caused serious health effects which included sores, anemia, and bone cancer. This is because radium is treated as calcium by the body, and deposited in the bones, where radioactivity degrades marrow and can mutate bone cells.

During the litigation, it was determined that the company's scientists and management had taken considerable precautions to protect themselves from the effects of radiation, yet had not seen fit to protect their employees. Worse, for several years the companies had attempted to cover up the effects and avoid liability by insisting that the Radium Girls were instead suffering from syphilis. This complete disregard for employee welfare had a significant impact on the formulation of occupational disease labor law.

As a result of the lawsuit, the adverse effects of radioactivity became widely known, and radium-dial painters were instructed in proper safety precautions and provided with protective gear. In particular, dial painters no longer licked paint brushes to shape them (which caused some ingestion of radium salts). Radium was still used in dials as late as the 1960s, but there were no further injuries to dial painters. This highlighted that the harm to the Radium Girls could easily have been avoided. 

Doesn't look like "syphilis" to me.  Looks more like "Radium Jaw"...  Very sad images indeed.