Manufacturing line/Submarines/Ballistic-missile submarine
Autonomous · Submarines

Ballistic-missile submarine

The quietest ship in the fleet. It patrols for months with no one aboard.

Phase 7 · 2033+Concept design
Displacement
20,815 t
Reactor
120 MWt
Fuel burn
≈ 5.25 g / hr
Crew aboard
0
I · Blueprint
Side elevation, live systems
50 m100 m150 m200 mDEPTHAABBCCBow domeBow planesTorpedo tubesWeapon stowageRing framesFlank arrayMissileLaunch gas generatorDecay-heat tankShield bulkheadCondenserPower electronicsAft ballast tankStern tube & bearingStator vanesTowed arrayMain steam lineShielded passageMissile hatchesHull coatingSensor masts170.7 m length overall020810140711121309050601030415SECTION A–A · MISSILE COMPARTMENTØ 13.1 m hullCoatingPressure hullDeckRing frameLaunch hatchesMissile tube pair · 1 of 8MissileGas generatorSECTION B–B · REACTOR COMPARTMENTShielded passageShieldingTank / bilgeDecay-heat tankReactor vesselControl rodsCoreSprint pumpSECTION C–C · ENGINE ROOMTurbine-generatorPower electronicsBattery bufferCondenserSteam inSwitchboardDeckSections look forward. Hull diameter to scale; internal arrangement generic.
01Pump-jet propulsor — rotor, stator vanes, ductPropulsion
02Control surfaces — X-stern & bow planesStructure
03Shaft, stern tube & sealPropulsion
04Propulsion motorPropulsion
05Turbine-generator & condenserPower
06Reactor compartment — integral reactor: core, steam generators and pressurizer in one vesselPower
07Missile compartment — 16 tubesMission systems
08Outer hull, pressure hull & ring framesStructure
09Battery buffer — 6 MWhPower
10Sail — masts & sensorsStructure
11Autonomous command coreMission systems
12Weapons room & tubesMission systems
13Spherical bow sonarMission systems
14Main ballast tanksStructure
15Towed array & reelMission systems
II · Power & drivetrain

Silence is the whole job.

Electric drive removes the reduction gear, the loudest part of a submarine. Power comes from a life-of-ship reactor, so patrol length is set by maintenance, not fuel.

Natural-circulation reactor and direct drive — rotating view
A tall 120 MWt integral reactor carries its steam generators inside the vessel and circulates by convection at patrol speed, so no coolant pump runs on patrol. Its four-stage 36 MWe turbo-generator feeds a 30 MW motor at 120 rpm, bolted straight to the pump-jet shaft: no reduction gear. The arrangement is generic.
01Integral reactor vessel — 120 MWt, steam generators inside, life-of-ship core
02Natural circulation — riser up the core, downcomer at the wall; sprint pumps only above 25% power
03Steam turbo-generator — 4 stages, 36 MWe
04Condenser — sea-water cooled
05Main switchboard — 6.6 kV, electric drive
06Propulsion motor — 30 MW permanent-magnet, direct drive at 120 rpm
07Pump-jet rotor — 11 blades, in its duct
08Shaft — no gearbox: the loudest part of a submarine, removed
Pump-jet rotor
Power plantPressurized reactor, 120 MWt
Shaft output≈ 30 MW, electric drive
FuelHighly enriched uranium, ≈ 93% U-235
Consumption≈ 5.25 g fissile / hr
Metal content≈ 93% high-yield steel
Naked drivetrain — energy to motion
Conceptual · not to scaleREACTOR COMPARTMENT · SHIELDEDReactor · 120 MWtIn-vessel steam generatorTurbineGeneratorPower electronicsPM motorShaft ≈ 30 MWPump-jetPressurizerRiserDowncomerSprint pumpMain steamSeawaterCondenserFeed pumpBattery bufferHull · shaft sealThrust bearingStatorRotor
III · How it is put together

Built in blocks, joined, then brought to life.

Blocks are fabricated in parallel, joined in sequence, and the power module and autonomy core go in last. The loop below replays the build order.

POWER MODULE
I
Pressure-hull rings rolled & welded
II
Modules outfitted before joining
III
Power module sealed in
IV
Sail & sensors fitted
V
Float-off & dive trials
IV · Specification

Concept specification.

Design specification for the autonomous ballistic-missile submarine.

Length overall
170.7 m
Displacement (submerged)
20,815 t
Missile tubes
16
Power plant
Pressurized reactor, 120 MWt
Consumption
≈ 5.25 g fissile / hr
Core life
Life of ship
Speed (submerged)
20+ kn
Propulsor
Pump-jet, electric drive
Patrol
Continuous, remote command
Sonar
Spherical bow array
Electric output
≈ 36 MWe, 30% steam cycle
Shaft output
≈ 30 MW, no reduction gear
Natural circulation
No coolant pumps below 25% power; 13% at 8 kn patrol
Battery buffer
6 MWh; 1.3 hr at 8 kn patrol
Metal content
≈ 93% high-yield steel
Crew aboard
0
Onboard compute
Four AI modules and a verifier that must always agree
Modules4 AI modules (navigation & patrol plan; sonar classification; ship control & plant; verifier) + 2 certified safety controllers; the weapons system is separate and under human control ashore
CPU64 cores (4 × 16) + 4 lockstep real-time cores per module
AI throughput20,000 TOPS total (4 × 5,000, INT8 / FP4 sparse)
Memory4 × 128 GB LPDDR6, 600 GB/s per module
Power draw400 W compute; ≈ 0.7 kW with sonar front-ends and 4 mast cameras — 0.002% of the 36 MWe plant
Process node2 nm-class SoCs; safety controllers on a mature 16 nm node, 15-year supply
RedundancyEvery sensor is wired to both module pairs. Each module is primary for its own job and hot standby for its partner; the verifier must agree before any change of depth, speed or course, and any one module can hold the boat safe. A software fault can never drive the submarine outside its certified safe envelope: two SIL 3 controllers own reactor protection, depth and ballast on their own depth gauges, plane and rudder angle sensors, shaft encoder and reactor instruments. Weapons release is never an onboard software decision.
SensorsSpherical bow array, flank and towed arrays, 4 mast cameras on an automotive Ethernet camera switch, inertial navigation, 2,400 plant sensors
LinkVery-low-frequency receive on patrol; satellite at communication depth; the patrol plan is carried aboard. Motor drives close their own current loop at 1 kHz; every safety loop closes aboard.
Service lifeThe boat serves 42 years on one core. Compute is a line-replaceable unit, swapped at mid-life.
On patrol the boat listens, stays quiet and follows a plan set ashore. Its modules classify sonar contacts and keep the boat within its box; a verifier module must agree with every manoeuvre. The weapons system is separate, and release authority stays with humans ashore.
Today vs IC
Power and crew: today’s missile submarine beside the IC design
Today · ballistic-missile submarineIC design
Size and tubes170.7 m, 18,750 t, 24 tubes; the successor in build is 20,815 t with 16 tubes170.7 m, 20,815 t, 16 tubes
ReactorPressurized-water reactor, rating not published; the successor gets a life-of-ship core of ≈ 42 years120 MWt integral reactor, natural circulation on patrol, life-of-ship core
Drive2 geared steam turbines, ≈ 26 MW → reduction gear → 7-blade propeller; the successor moves to electric drive36 MWe turbo-generator → 30 MW direct-drive motor at 120 rpm → 11-blade pump-jet
Speed20 kn submerged (published)20+ kn submerged; 8 kn patrol at 13% reactor load
Crew155 per crew, two crews per boat0; the patrol plan is set ashore and weapons release stays with humans ashore
The IC column is the design shown on this page. Sources for the Today column are listed in BUILD_NOTES.md.
Runs on The Brain
Every patrol of this boat is planned by The Brain’s orchestration layer, mirrored in the fleet’s digital twin, and re-planned at every contact.
See how it works →
Continue
Extra-large unmanned undersea vehicle →← Attack submarine