Expanded Fission Engine



An EXpanded Fission Engine or EX Fission Engine is a Fission Engine made less dense in order to reduce weight, but at the cost of increasing bulk.

It follows the rules for XXL Fusion Engines except applying the 1/3 weight (and the corresponding rounding) to the regular Fission type rather than to the Fusion type. It occupies 6 slots in each side torso for IS and 4 for Clans. Clans don't use regular Fission engines, but may mount EX Fission Engines.

Much as with Extra-Extralight Fusion Engines, having the engine shielding down to the bare minimum for safe operation, the EX Fission engine produces waste heat even standing still, and it generates double the amount of heat for the use of a 'Mech's movement systems compared to its non-EXpanded precessor.

A significant difference with Fusion XXL engines is that the EX Fission Engine only costs 1.25 times as much as the equivalent standard Fission engine of the same rating, while the XXL Fusion engine costs 5 times as much as an XL one.

The minimum weight for Expanded Fission Engines is 1.75 tons (if using fractional accounting), or 2 tons (if not), compared to the 5 tons of regular Fission engines.

An Expanded Fission Engine still requires 5 Heatsinks. These are included in the case of mounting inside a vehicle or equivalent unit, but vehicles must still must suffer a 50% weight penalty on the engine's weight as with a regular Fission one. However, this extra 50% is not as punishing compared to the overall tonnage saved with heatsinks due to the much lowered base weight to being with, and due to the fact that vehicles don't track the extra heat produced by the engine.

Expanded Fission Heat Radiation Leakage
The sealing and shielding in Expanded Fission Engines is imperfect, and as such some radiation leaks in the heat vented to cool the reactor. This is usually no problem as long as the heat is properly dissipated, but starts to be dangerous to the crew when overheated.  In heat-tracking units, at the end of any turn where an EX Fission equipped unit is above zero heat (after dissipating), make a piloting check. If failed, radiation from the heat exhaust leaks inside the unit and deals 1 damage to every crew member. This radiation damage doesn't trigger consciousness checks.  If the unit does not track heat, instead, apply this end-of-turn piloting check if the unit was sucessfully hit by at least one heat-inducing attack. Heat-inducing attacks include the regular assaults of Plasma Rifles, Plasma Cannons, any type of Flamer, and any class of hit by an Inferno ammunition.

Probable uses
The following pages link to the Expanded Fission Engine: linksto=Expanded Fission Engine linksto=Expanded Fission Engines linksto=expanded fission engine linksto=expanded fission engines