20 Nuclear Acronyms for People New to the Industry

  People

1

 SQEP

 Suitably Qualified and Experienced Person (or Personnel). The  term describes a person that has the training and experience  needed for a specific role.

  Nuclear authorities

2

 ONR

 The Office for Nuclear Regulation is responsible for all nuclear  sector regulation across the UK.

3

 CNC

 Civil Nuclear Constabulary is the armed police force which is  responsible for the protection of civil nuclear material.

  Design and Operations

4

 BAT

 Best Available Technique or Technology: Applying BAT is a UK  regulatory requirement that must be demonstrated.

5

 ALARP

 As Low As Reasonably Practicable (social and economic factors  taken into consideration): ALARP is a fundamental requirement of  UK health and safety legislation.

6

 RCA

 RCA Radiation Control Area RCA Reactor Controlled Area

7

 Outage

 A Period of reactor shutdown during which a nuclear power  station ceases to generate electricity. Can be planned, for  example for maintenance, or unplanned. Many reactor types can  only be refuelled during an outage.

8

 Safety Case

 A documented body of evidence which is submitted to regulators  to provide a convincing and valid argument that a specified  system is safe for a given application in a given context or  environment.

  Designated areas and key equipment  

9

 NPP

 Nuclear Power Plant

10

 Nuclear Island (NI)

 That part of a nuclear power plant which incorporates all  equipment, installed within the reactor and reactor auxiliary  buildings. The boundaries of the NI are normally defined as being  one metre outside these buildings for piping and two metres for  cable.

11

 Conventional  Island

 That part of a nuclear power plant that does not form part of the  nuclear island. The conventional island is sub-divided into the  turbine generator (i.e. the plant that converts the nuclear steam  into electricity) and the balance of the conventional plant &  equipment.

12

 CWS

 Cooling Water System

13

 NSSS

 Nuclear steam supply system: That part of an NPP which  incorporates the nuclear heat source and the heat transport  system. Usually referred to as “N-triple S”.

  Nuclear reactors

 Note: The types of reactor tend to be categorised by 4 main design features:

1. The nuclear fuel. The fuel for a nuclear power station is uranium ore that is enriched into pellets. The process by which uranium ore is mined, processed, enriched, used, possibly reprocessed and disposed of is known as the nuclear fuel cycle.
2. The Cladding. The pellets are surrounded with cladding to contain & separate the fuel from the coolant.
3. The Moderator. Used to control the speed of the neutrons and reaction rate.
4. The Coolant. Used to transfer heat from the fuel element (via the clad surface) to the steam-raising system.

14

 MAGNOX  

 ‘First Generation’ gas-cooled reactor (GCR) that uses carbon  dioxide as coolant, graphite as a neutron moderator and natural  uranium fuel in a magnesium alloy cladding. The GCR was able to  use natural uranium as fuel, without relying on supplies of  enriched uranium.

15

 AGR

 Advanced Gas Cooled Reactor: British designed ‘Second  generation’ nuclear reactors, characterised by steam generated  inside the reactor being directly passed to the turbine, simplifying  the process of energy production. Similar to the first generation  reactors they use graphite as the neutron moderator and carbon  dioxide as coolant. The AGR operates at a higher gas temperature  for improved thermal efficiency, but requires stainless steel fuel  cladding to withstand the higher temperature, and uses enriched  uranium fuel.

16

 PWR

 Pressurised Water Reactor: PWRs are the most common type of  nuclear reactor. These reactors use a pressure vessel to contain  the nuclear fuel, control rods, moderator, and coolant. They use  enriched uranium oxide fuel, clad in zirconium alloy. In contrast to  a BWR with one coolant loop, heat is transferred to a lower  pressure secondary coolant without mixing the two fluids and  pressure in the primary coolant loop prevents the water from  boiling within the reactor.

17

 BWR

 Boiling Water Reactors are the world’s second most common type  of reactor that use demineralized water as a coolant and  neutron  moderator, like a PWR, but at a lower pressure, which  allows the  water to boil inside the pressure vessel. Unlike a PWR,  there is no  secondary loop. The steam is directly used to drive a  turbine,  after which it is cooled in a condenser and converted  back to  liquid water. This water is then returned to the reactor core,  completing the loop.

18

 EPR

 Evolutionary Pressurised Reactor or European Pressurised  Reactor: A type of PWR reactor designed by AREVA, the first of  which are being constructed at Olkiluoto in Finland, Flamanville in  France and Taishan in China. Two EPR reactors are planned to  be built at Hinkley Point C.

19

 Generation

 I, II, III, IV

 Generation I The earliest commercial nuclear power station  designs, including Magnox in the UK.

 Generation II The set of designs which makes up the bulk of   today's nuclear power stations, including PWRs, and AGR’s.

 Generation III Reactor designs available for construction today,  making more use of passive safety features including EPR’s.

 Generation IV reactors are designs that are currently under  development and are expected to be ready for deployment  between 2020 and 2030.

20

 Fusion reactors

 All current nuclear power plants are critical fission reactors,  however, ITER (International Thermonuclear Experimental  Reactor) a large-scale scientific demonstration plant is under  construction in France to develop the technological and scientific  feasibility of fusion energy.