Tritium and 14C are two most important radionuclides released from nuclear facilities to the environment, and 14C contributes dominant radiation dose to the population around nuclear power plants. This paper presents an overview of the production, pathway, species and levels of tritium and 14C in nuclear facilities, mainly nuclear power plants. The methods for sampling and collection of different species of tritium and 14C in the discharge gas from the stack in the nuclear facilities, atmosphere of the nuclear facilities and environment are presented, and the features of different methods are reviewed. The on-line monitoring methods of gaseous tritium and 14C in air and laboratory measurement methods for sensitive determination of tritium and 14C in collected samples, water and environmental solid samples are also discussed in detailed. Meanwhile, the challenges in the determination and speciation analysis of tritium and 14C are also highlighted.

1. Introduction
 2. Sources and 14C and tritium in the environment
  2.1 Production of 14C and its pathways to theenvironment
   2.1.1 Production of 14C in the nature and nuclearweapons testing
   2.1.2 Production and pathways of 14C in nuclearreactors
  2.2 Production of tritium and its pathways tothe environment
   2.2.1 Production of tritium in the nature and nuclearweapons testing
   2.2.2 Production and pathways of tritium in thenuclear reactors
  2.3 Releases of tritium and 14C from nuclearfuel reprocessing plants
  2.4 Releases of tritium and 14C from nuclearaccidents and other nuclear facilities
 3. Approaches and setup for monitoring14C and tritium in nuclear facilities andenvironment
  3.1 Monitoring of 14C in air, concerning collectionefficiency of different forms of 14C
   3.1.1 Collection of 14CO2 from the stacks andatmosphere
   3.1.2 Collection of all species of gaseous 14C fromthe stacks and atmosphere
   3.1.3 Collection of different species of gaseous14C from the stacks and atmosphere
  3.2 Monitoring tritium in air concerning separationof different species of tritium
  3.3 Combined system for monitoring bothtritium and 14C in air
  3.4 Monitoring of 14C in water, speciation analysisof 14C in water
  3.5 Monitoring of tritium in water, concerningorganic and inorganic tritium
  3.6 Combined system for monitoring bothtritium and 14C in water
  3.7 Separation of tritium and 14C in solid wasteand environmental samples
 4. Analytical methods for measurement of14C and tritium
  4.1 Measurement of tritium using LSC
  4.2 Measurement of 14C using LSC
  4.3 Measurement of tritium and 14C usingionization chamber (on-line measurement)
  4.4 Measurement of 14C using AMS
 5. Challenges, problems and methods inmonitoring of tritium and 14C
 Acknowledgement
 REFERENCES

• Xiaolin Hou(Technical University of Denmark, Center for Nuclear Technologies) Corresponding Author