Physical plant

The design and equipment in a Nuclear Power Plant, has for the most part remained stagnant over the last 30 years [1] There are three types of reactor cooling mechanisms: “Light water reactors, Liquid Metal Reactors and High Temperature Gas-Cooled Reactors”.[2] While for the most part equipment remains the same, there have been some minimal modifications to existing reactors improving safety and efficiency.[3] There have also been significant design changes for all these reactors. However, they remain theoretical and unimplemented.[4] Nuclear power plant equipment can be separated into two categories: Primary systems and Balance-Of-Plant Systems.[5] Primary systems are equipment involved in the production and safety of nuclear power.[6] The reactor specifically has equipment such as, reactor vessels usually surrounding the core for protection, the reactor core which holds fuel rods. It also includes reactor cooling equipment consisting of liquid cooling loops, circulating coolant. These loops are usually separate systems each having at least one pump.[7] Other equipment includes Steam generators and pressurizers that ensures pressure in the plant is adjusted as needed.[8] Containment equipment is the physical structure built around the reactor to protect the surroundings from reactor failure.[9] Lastly primary systems also include Emergency core cooling Equipment and Reactor protection Equipment.[10] Balance-Of-Plant Systems are equipment used commonly across power plants in the production and distribution of power.[11] They utilize; Turbines, Generators, Condensers, Feedwater equipment, auxiliary equipment, fire protection equipment, Emergency power supply equipment and used fuel storage.[12]

Fiber optic splicing in a mobile lab.

Economic constraints such as capital and operating expenditure lead to Passive Optical Networks as the primary fiber optic model used to for connecting users to the fiber optic plant.[14] A central office hub utilities transmission equipment, allowing it to send signals to between one and 32 users per line.[14] The main fiber backbone of a PON network is called an optical line terminal.[15] The operational requirements such as maintenance, equipment sharing efficiency, sharing of the actual fiber and potential need for future expansion, all determine which specific variant of PON is used.[14] A Fiber Optic Splitter is equipment used when multiple users must be connected to the same backbone of fiber.[14] EPON; a variant of PON, which can hold 704 connections in one line.[15] Fibre networks based on a PON backbone have several options in connecting individuals to their network, such as fibre to the “curb/building/home”.[16] This equipment utilises different wavelengths to send and receive data simultaneously and without interference[15]

Base stations are a key component of mobile telecommunications infrastructure. They connect the end user to the main network.[17] They have physical barriers protecting transition equipment and are placed on masts or on the roofs/sides of buildings. Where it is located is determined by the local radio frequency coverage that is required.[18] These base stations utilize different kinds of antennas, either on buildings or on landscapes to transmit signals back and forth [19] Directional antennas are used to direct signals in different direction, whereas line of sight radio-communication antennas, allow for communication in-between base stations.[19]

Base stations are of three types Macro, Micro and Pico cell sub-stations.[18] Macro cells are the most widespread used base station, utilizing omnidirectional or radio-communication dishes. Micro cells are more specialized; these expand and provide additional coverage in areas where macro cells cannot.[20] They are typically placed on streetlights, usually not requiring radio-communication dishes. This is because they are physically interconnected via fiber optic cables.[17] Pico cell stations are further specific, providing additional coverage only within a building when the coverage is poor. This will usually be placed on a roof or a wall in each building.[17]

Reverse osmosis plants use “Semi-Permeable Membrane Polymers”, that allow for water to pass through unabated, while blocking molecules not suitable for drinking.[22] Reverse Osmosis plants typically use intake pipes, which allow for water to be abstracted at its source. This water is then taken to pre-treatment centers, of which particles in the water are removed, with chemicals added to prevent water damage. HR-pumps and booster pumps are used to provide pressure, to pump the water at different heights of the facility, which is then transferred to a reverse osmosis module. This equipment depending on the specifications effectively filters out between 98 and 99.5% of salt from the water. Waste that is separated through these pre-treatment and reverse osmosis modules and taken to an energy recovery module, and any further excess is pumped back out through an outfall pipe. Control equipment is used to monitor this process, to ensure it continues running smoothly. When the water is separated it is then delivered to a household via a distribution network for consumption.[23] Pre-Treatment systems have intake screening equipment such as forebays and screens.[24] Intake equipment can vary in design, open ocean intakes are either placed onshore or off the shore. Offshore intakes transfer water using concrete channels into screening chambers to be transferred directly to pre-treatment centers, using intake pumps where chemicals will be added. It is then dissolved and separated from solids using a flotation device, to be pumped through a semi-permeable membrane.[25]

Electrodialysis competes with reverse osmosis systems and has been used industrially since the 1960s.[26] It uses cathodes and anodes at multiple stages to filter out Ionic compounds into a concentrated form leaving a more pure and safe drinking water. This technology does have a higher cost of energy so unlike reverse osmosis it is mainly used for Brackish water which has a lower salt content than seawater.[27]

Thermal distillation equipment is commonly used in the middle east similarly to Reverse Osmosis it has a water abstraction and pre-treatment equipment, although in MSF different chemicals such as anti-sealant and anti-corrosives are added. Heating equipment is used at different stages at different pressure levels until it reaches a brine heater. The brine heater is what provides steam at these different stages to change the boiling point of the water.[28]

Stakeholders have different responsibilities, for the maintenance of equipment in a water treatment plant.[43] In terms of the distribution equipment to the end user, it is mainly the plant owners who are responsible for the maintenance of this equipment. An Engineers role is more focused on maintaining the equipment used to treat water.[44] Public regulators, are responsible for monitoring water supply quality, ensuring it is safe to drink.[44] These stakeholders have active responsibility for these processes and equipment. Manufacturers primary responsibility, is off site, providing quality assurance of equipment function prior to use.[45]