A sudden increase in the pressure of the liquid in a pipeline brought about by an abrupt change in flow velocity. The pressure surge may cause a rupture of the piping and an extensive oil spill.

The technology of inert gas production by the removal of oxygen from air used on LNG tankers.

A valve which keeps the tank over pressure or under pressure within approved, limits. P/V valve provides for the flow of the small volumes of vapour, air or inert gas mixtures caused by thermal variations in a cargo tank.

MacGREGOR’s patented ‘hold overpressure system’ is a way of maximising the weathertightness of hatch covers.

A pressurized heavy-water reactor (PHWR) is a nuclear reactor that uses heavy water (deuterium oxide D2O) as its coolant and neutron moderator.

A pressurized water reactor (PWR) is a type of light-water nuclear reactor.

The most common direction or directions that the wind comes from at a location.

Preventive maintenance (PM) is a routine for periodically inspecting with the goal of noticing small problems and fixing them before major ones develop.

The mandatory wash of the cargo tanks prior to loading cargo.

The inner element designed to contain the cargo when the cargo containment system includes two barriers, (IGC CODE).

Equipment/systems essential for performance of primary bridge navigational functions: log, echo sounder, gyrocompass, radar, position-fixing system and electronic chart system.

A battery (galvanic cell) that is designed to be used once and discarded, and not recharged with electricity and reused like a secondary cell (rechargeable battery).

The primary containment system usually consists of a large metal and/or concrete structure (often cylindrical or bulb shaped) that contains the reactor vessel. The primary containment system is designed to withstand strong internal pressures resulting from a leak or intentional depressurization of the reactor vessel.

Primary energy is an energy form found in nature that has not been subjected to any human engineered conversion process.

Floors and bottom girders, side stringers and web frames, deck transverses and deck girders, vertical webs and horizontal stringers on bulkheads. Primary members support secondary stiffeners.

In an engine/generator set the engine is the prime mover.

The first coat of the coating system applied in the shipyard after shop primer application.

Probable reserves are volumes defined as "less likely to be recovered than proved, but more certain to be recovered than Possible Reserves".

Problem solving consists of using generic or ad hoc methods in an orderly manner to find solutions to problems.

Process engineering is the understanding and application of the fundamental principles and laws of nature that allow humans to transform raw material and energy into products that are useful to society, at an industrial level.