design features (such as leak detection) are provided on the assumptions of a single failure and the loss of off-site power, and by the incorporation of suitable redundancy, diversity and independence. Emergency core cooling Core cooling is provided in the event of a loss of coolant accident so as to minimize fuel damage and limit the escape of fission products from the fuel. The cooling provided ensures that: The limiting parameters for the cladding or fuel integrity (such as temperature) do not exceed the acceptable value for design basis accidents (for the relevant reactor design); Possible chemical reactions are limited to an allowable level; The alterations in the fuel and internal structural alterations do not significantly reduce the effectiveness of the means of emergency core cooling; and Cooling of the core is ensured for a sufficient time. Design features (such as leak detection, appropriate interconnections and isolation capabilities) and suitable redundancy and diversity in components are provided in order to fulfil these requirements with sufficient reliability for each PIE, on the assumption of a single failure. Adequate consideration is given to extending the capability to remove heat from the core following a severe accident. Inspection and testing of the emergency core cooling system The emergency core cooling system is designed to permit appropriate periodic inspection of important components and to permit appropriate periodic testing to confirm the following: The structural integrity and leak tight integrity of its components; The operability and performance of the active components of the system in normal operation, as far as feasible; and The operability of the system as a under the conditions specified in the design basis, to the extent practicable. Heat transfer to an ultimate heat sink Systems are provided to transfer residual heat from all components important to safety to an ultimate heat sink. This function is carried out at very high levels of reliability in operational states and in design basis accidents. The reliability of the systems is achieved by an appropriate choice of measures including the use of proven components, redundancy, diversity, physical separation, interconnection and isolation. Adequate consideration is given to extending the capability to transfer residual heat from the core to an ultimate heat sink so as to ensure that, in the event of a severe accident, acceptable temperatures can be maintained in structures, systems and components important to the
design features (such as leak detection) are provided on the assumptions of a single failure and the loss of off-site power, and by the incorporation of suitable redundancy, diversity and independence. Emergency core cooling Core cooling is provided in the event of a loss of coolant accident so as to minimize fuel damage and limit the escape of fission products from the fuel. The cooling provided ensures that: The limiting parameters for the cladding or fuel integrity (such as temperature) do not exceed the acceptable value for design basis accidents (for the relevant reactor design); Possible chemical reactions are limited to an allowable level; The alterations in the fuel and internal structural alterations do not significantly reduce the effectiveness of the means of emergency core cooling; and Cooling of the core is ensured for a sufficient time. Design features (such as leak detection, appropriate interconnections and isolation capabilities) and suitable redundancy and diversity in components are provided in order to fulfil these requirements with sufficient reliability for each PIE, on the assumption of a single failure. Adequate consideration is given to extending the capability to remove heat from the core following a severe accident. Inspection and testing of the emergency core cooling system The emergency core cooling system is designed to permit appropriate periodic inspection of important components and to permit appropriate periodic testing to confirm the following: The structural integrity and leak tight integrity of its components; The operability and performance of the active components of the system in normal operation, as far as feasible; and The operability of the system as a under the conditions specified in the design basis, to the extent practicable. Heat transfer to an ultimate heat sink Systems are provided to transfer residual heat from all components important to safety to an ultimate heat sink. This function is carried out at very high levels of reliability in operational states and in design basis accidents. The reliability of the systems is achieved by an appropriate choice of measures including the use of proven components, redundancy, diversity, physical separation, interconnection and isolation. Adequate consideration is given to extending the capability to transfer residual heat from the core to an ultimate heat sink so as to ensure that, in the event of a severe accident, acceptable temperatures can be maintained in structures, systems and components important to the
Module04%20Design%20of%20a%20nuclear%20reactor.docx