Voyage of the Devilfish

PRESSURIZER Tank in the primary coolant system that keeps the water in liquid form even up to 500 degrees by using heaters and raising the water in the pressurizer to even higher temperatures and pressures.

PRESSURIZER LEVEL The level of the pressurizer tank is the main indication of the amount of primary coolant in the primary coolant system. Large changes in core temperature can raise or lower the level due to thermal expansion or contraction of the water. A loss-of-coolant accident is detected by a falling pressurizer level.

PREUNDERWAY CHECKLIST Set of checklists used to get a submarine under way, including valve lineups and switch position checks. Considered of equal complexity and scope to a Space Shuttle countdown checklist.

PRIMARY COOLANT SYSTEM The piping system that circulates primary coolant from the reactor core to the steam generators (boilers) using reactor main coolant pumps. As opposed to the “secondary” coolant, the steam going from the boilers to the turbines for propulsion.

PRIORITY A level of urgency of a radio message below IMMEDIATE and above ROUTINE. Reception guaranteed on the same day.

PROMPT CRITICAL Under some conditions, uranium can be critical on fast neutrons instead of thermal neutrons. One example is a bomb undergoing a nuclear explosion. A second is a core in a reactivity accident such as a control rod jump, where the core becomes prompt critical, critical on the fast neutrons that are emitted “promptly” by the fission reaction.

A core that is prompt critical is milliseconds from either a steam explosion or a prompt critical rapid disassembly.

PROMPT CRITICAL RAPID DISASSEMBLY Polite term for the unlikely event of a core undergoing a nuclear explosion.

PROPULSOR Sophisticated screw that uses ducting and multistage water turbine blades for propulsion instead of a conventional screw. Similar to a water jet. Extremely quiet and nearly impossible to cavitate. Disadvantage includes slow response and acceleration due to relatively low thrust compared to conventional screws.

P.A. CIRCUIT ONE Ship wide Public Address announcing system.

P.A. CIRCUIT SEVEN Speaker announcing system used between the Conn, Maneuvering, the bridge, and the torpedo room.

P.A. CIRCUIT TWO Similar to P.A. Circuit One, except that it only announces in the engineering spaces (aft of frame 57).

RANGE Distance to a contact.

RANGE GATING The action of an emitter of active sonar pulses. The ship being tracked can tell how close the pinging platform is by the time between pulses, assuming the transmitter does not ping the second pulse until it receives a return ping from the first pulse. The closer the pinging object gets to own ship, the shorter the interval between pings.

REACTOR Nuclear core. An assembly of fuel elements containing U-235, control rods, shielding, and inlet and discharge of primary coolant. Heat source that allows steam to be generated in the steam generators to produce propulsion and electricity.

REACTOR COMPARTMENT Compartment housing the reactor, pressurizer, steam generators, and reactor main coolant pumps. Access fore and aft is through a shielded tunnel, since anyone inside the compartment when the reactor is critical would be dead within a minute from the intense radiation.

REACTOR MAIN COOLANT PUMPS Massive pumps, each consuming between 100 and 400 horsepower, that force main coolant water through the reactor and then to the steam generators. Three are in each main coolant loop. Special design allows zero leakage.

REACTOR PLANT CONTROL PANEL (RPCP) Control panel in the maneuvering room where the Reactor Operator controls the reactor.

REACTOR PROTECTION Circuitry containing safety interlocks and control functions preventing reactor damage in an accident.

REACTOR VESSEL Heavy steel shell housing the reactor core.

REAR GUARD SONAR New Russian passive and active sonar that looks astern into the baffles. Mounted in the aft section of the pod atop the rudder of the Project 985 (Kaliningrad or OMEGA) class Russian submarines. Eliminates need to do baffle clearing maneuvers.

RECONSTRUCTION Six-hour period following a watch when an enemy submarine is trailed. The offwatch firecontrol team meets in the officer’s wardroom and compares data from charts, geo plots, computer readbacks, and logs, in an effort to “get the story straight” for the patrol report. Conflicting information is resolved during reconstruction.

REDUCTION GEAR The mechanism that converts the high RPMS of the two main engines (propulsion turbines) to the slow RPM of the screw. Solves the problem of how to get two turbines to drive a single screw. Also solves the problem of how to let the main engines rotate at high RPM where they are efficient while letting the screw rotate at the low RPM where it is efficient. Unfortunately, the reduction gear is one of the noisiest pieces of equipment aboard.

RELAY Electrical device that acts as a smart switch.