the shape of things to come

vert a standard into an XL—such a process is not easy and the
required parts cost almost as much as new XL. Furthermore,
some manufacturers don’t strive for parts commonality at all,
so I guess my message here is, “Techs, if you’re trying to be the
next Battle Magic and convert an old clunker into an XL engine,
check the manufacturer’s specs for both engines before
you try it. A fusion engine is terrible thing to waste.”
Engine Cooling Systems
In addition to the regenerative cooling system and heat
sinks, fusion engines have a basic, integral cooling system
separate from the regular heat sink network. This involves a
set of liquid nitrogen jackets over key components and allows
the engine to operate at minimal levels without outside cooling
systems. Any exertions require the greater cooling capacity
of the main heat sink system.
Oversized Engines
A slight digression here: For the fi rst couple of decades
in BattleMech design, engineers used oversized fusion engines—power
plants that were larger than needed today for
a given speed category of ’Mech. It was hoped that this would
THE GREAT MYTH MYTH
But while the plasma is cooling down from jillions of degrees—yes,
“jillion” is a technical term, my youngest son assures
me—the air is heated up to thousands of degrees and
will promptly burst back out the hole in a gout of white-hot
fl ame. Since a weapon heavy enough to puncture a reactor
also generally destroys the core frame of a ’Mech, you get a
blinding fi reball accompanied by the ’Mech falling apart. It
looks like a nuclear fi reball bursting out of the ’Mech’s chest,
but it’s literally just a load of hot air.
And that’s a brutal way to kill a fusion engine. When you
let oxygen loose inside an operating reactor, the super-hot
oxygen just ravages the lining of the reactor and the delicate
sensors and probes in there. It gets turned into a fl ashrusted
mess.
Now, I earlier said that a reason the reactor shielding is so
heavy is that it serves as a heat sink during a hard shutdown
without a functional cooling system. I also said that there isn’t
enough heat stored in the “dead” plasma to damage shielding.
Well, there are circumstances where this ultimate in passive
safety systems can be overwhelmed, and you can get
the fabled “nuclear reactor” explosion…though it’s more like
a bursting balloon than a nuclear bomb. See, reactor shielding
isn’t a great thermal conductor, so it takes time for heat
to soak through the shielding. That means the interior of the
reactor can get very hot while it’s waiting for the heat to soak
outward. Engine designers know that and allow for that, at
least for reasonable levels of heat left in the plasma. Over the
centuries, some clever and stupid MechWarriors have fi gured
out that if they overcharge the engine, then kill the magnetic
containment fi eld quickly, they can dump so much heat into
the reactor walls that the reactor lining explosively evaporates.
This over pressurizes the reactor, which bursts and
causes a respectable explosion. Again, however, the eff ect is
not very much like a nuclear bomb at all.
provide assorted, ill-defi ned boosts in combat. Unfortunately,
these engines simply ran too hot or shut themselves down
with overloads. The problem—in part—was that BattleMech
systems could only draw so much power at one time.
Ramming more down their throats didn’t help.
So, now that we’ve found a major heat source in ’Mechs,
let’s talk about how to get rid of it—
Yes, question? Speak up for the microphone… No. No; just
stop there. Fusion reactors are nothing like fusion bombs.
Tharkad City— Yes, I know. Calm down and let me explain.
HEAT SINKS
To become fusion-powered avatars of war gods that can
stalk airless wastes or battle below the waves, BattleMechs are
well-sealed, well-insulated vehicles. While that prevents heat
from getting in, it also prevents heat from getting out, and the
endless megawatts of power consumed by a BattleMech end
up as a lot of waste heat. So, BattleMechs have heat sinks.
Now, fi rst off , there’s been some confusion among the more
technical journals about what BattleMech heat sinks are.
Basically, BattleMech heat sinks are misnamed. It’s an honest
mistake for Kaumberg’s more technically literate to miss the
This, incidentally, is why you don’t see fusion-powered
battle armors and fusion engines much smaller than 250
kilograms. Smaller fusion engines just don’t have the mass
to soak up the remaining heat of a hard shutdown and can
much more easily explode as described above.
And then there’s the reactor explosion at Tharkad City,
which was yet another sort of fusion engine explosion and
illustrates why you only get fusion engine explosions after
multitudes of unlikely failures. As I’ve read, the Tharkad Power
& Heat power is—er, was—a multi-functional industrial facility,
including the cornerstone of TP&H’s radioactive waste
treatment. TP&H used the facility to irradiate radioactive
waste into non-radioactive or short half-life isotopes. It was
also an ancient facility built during the old Star League. While
the reactor was well maintained, the aging roof was carrying
a heavy winter snowfall. And since it was a fusion reactor, the
building wasn’t reinforced like the containment domes of
those primitive fi ssion reactors outside of town here. There
would be no real explosion risk to contain. The reactor vessel
and shielding would handle that.
But over the decades, it seems, TP&H had expanded its
profi table Star League-era facilities for producing industrial
heat and processing more radioactive waste. That involved
installing extra tanks of sodium coolant outside of the protected
areas. It seemed reasonable and quite defensible at the
time, but hadn’t allowed for the centuries of penny-pinching
deferred building maintenance. When the Word bombarded
Tharkad City, the tremors collapsed the old roof and dumped
hundreds of tons of snow and debris on hundreds of tons of
molten sodium. There was a large chemical explosion, one
big enough to generate a credible mushroom cloud, and a
fi re amongst tanks of molten salts holding dissolved radioactive
wastes. Frankly, the reactor was almost a bystander to the
whole episode.
i
INTRODUCTION
CONSTRUCTION
BASICS
BATTLEMECH
CONSTRUCTION
INDUSTRIALMECH
CONSTRUCTION
PROTOMECH
CONSTRUCTION
COMBAT VEHICLE
CONSTRUCTION
SUPPORT VEHICLE
CONSTRUCTION
CONV. INFANTRY
CONSTRUCTION
BATTLE ARMOR
CONSTRUCTION
AEROSPACE UNIT
CONSTRUCTION
WEAPONS AND
HEAVY EQUIPMENT
INFANTRY WEAPONS
AND EQUIPMENT
COSTS AND
AVAILABILITY
BATTLE VALUE
INDEX
RECORD SHEETS
37