Nuclear plant safety design philosophy

Operating safety in nuclear power plants is assured through the integrity of three distinct barriers between the fission products and the environment and through permanent operational availability of the related safety systems. This design philosophy is termed defense in depth , and the continued safety of a plant is maintained by the integrity of these three barriers ... 

The basic safety philosophy of nuclear plant design and operation is that the design should be conservative, there should be ample safety margins in operation, and redundant and diverse components and systems should be provided to cover the unknown imcertainties. A concept called defense-in-depth is used in developing reactor safety. 

Defence in depth is a comprehensive approach to safety that has been developed by nuclear power experts to ensure with high confidence that the public and the environment are protected from any hazards posed by the use of nuclear power for the generation of electricity. The concepts of defence in depth and safety culture have served the nuclear power industry well as a basic philosophy for the safe design and operation of nuclear power plants. 

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