Salinity is the saltiness or amount of salt dissolved in a body of water, called saline water.

Saline water (more commonly known as salt water) is water that contains a high concentration of dissolved salts (mainly sodium chloride).

SAFSTOR is a nuclear decommissioning method in which a nuclear power plants/facilities governed by the United States Nuclear Regulatory Commission, is "placed and maintained in a condition that allows the facility to be safely stored and subsequently decontaminated (deferred decontamination) to levels that permit release for unrestricted use".

A safety valve is a valve that acts as a fail-safe.

Safety standards are standards designed to ensure the safety of products, activities and processes, etc.

Safety engineering is an engineering discipline which assures that engineered systems provide acceptable levels of safety.

A safety engineer is a company employee whose primary responsibility is designing procedures and implementing systems to keep staff safe. By combining a knowledge of health and safety with systems engineering, they are able to ensure that software, machinery, chemicals, and other environmental factors are safe.

A safety data sheet (SDS) is a document that lists information relating to occupational safety and health for the use of various substances and products.

Safety is the state of being "safe", the condition of being protected from harm or other non-desirable outcomes.

A sacrificial metal is a metal used as a sacrificial anode in cathodic protection that corrodes to prevent a primary metal from corrosion, galvanization or rusting.

Sacrificial anode, is the main component of a galvanic cathodic protection system used to protect buried or submerged metal structures from corrosion.

A process that produces methane and water from a reaction of hydrogen with carbon dioxide at elevated temperatures and pressures in the presence of a nickel catalyst.

Rural electrification is the process of bringing electrical power to rural and remote areas.

A disc used in pressurised piping circuits and vessels to protect the pressure integrity of the vessel or piping circuit. The disc rupture pressure is decided at manufacture and cannot be changed.

The number of hours that a machine or system is in operational mode.

Running costs include the cost of any fuel, maintenance costs, repair costs, wages, handling any wastes etc.

Hydroelectricity plants that do nor require the creation of a water storage area. The water is returned to the river at a lower elevation. Small variations of these can be floating.

Run-around systems are a hybrid heat recovery system that incorporates characteristics from other heat recovery technology to form a single device, capable of recovering heat from one air stream and delivering to another a significant distance away.

The swept diameter of the turbine blades.

Rotor blades are connected to the wind turbine rotor. Aerodynamic forces, the same as on a aircraft wing, act on the blades to impart rotation.