IEEE 497-2002 pdf download

IEEE 497-2002 pdf download.IEEE Standard Criteria for Accident Monitoring Instrumentation for Nuclear Power Generating Stations
4. Selection criteria This clause provides criteria for identifying the plant specific variables for accident monitoring.
The variable types will be referred to as A, B, C, D, and E. Criteria for the selection of each type of variable are given below and summarized in Table 1.
4.1 Type A variables
Type A variables are those variables that provide the primary information required to permit the control room operating staff to:
a) Take specific planned manually-controlled actions for which no automatic control is provided and that are required for safety systems to perform their safety-related functions as assumed in the plant Accident Analysis Licensing Basis.
b) Take specific planned manually-controlled actions for which no automatic control is provided and that are required to mitigate the consequences of an AOO.
Type A variables provide information essential for the direct accomplishment of specific safety-related functions that require manual action. These variables are a subset of those necessary to implement the plant specific emergency procedure guidelines (EPGs) or the plant specific emergency operating procedures (EOPs) or the plant abnormal operating procedures (AOPs). Type A variables do not include those variables that are associated with contingency actions that may also be identified in written procedures.
4.2 Type B variables
Type B variables are those variables that provide primary information to the control room operators to assess the plant critical safety functions. Any plant critical safety functions addressed in the EPGs or the plant specific EOPs that are in addition to those identified above shall also be included.
The Type B variables shall be those necessary to implement the plant functional restoration EPGs, plant specific EOPs, and the plant critical safety function status trees, if applicable.
4.3 Type C variables Type C variables are those variables that provide primary information to the control room operators to indicate the potential for breach or the actual breach of the three fission product barriers (extended range): fuel cladding, reactor coolant system pressure boundary, and containment pressure boundary. The selection of these variables represents a minimum set of plant variables that provide the most direct indi- cation of the integrity of the three fission product barriers and provide the capability for monitoring beyond the normal operating range.
4.4 Type D variables Type D variables are those variables that are required in procedures and LBD to:
a) Indicate the performance of those safety systems and auxiliary supporting features necessary for the mitigation of design basis events.
b) Indicate the performance of other systems necessary to achieve and maintain a safe shutdown condition.
c) Verify safety system status. The Type D variables shall be based upon the Plant Accident Analysis Licensing Basis and those necessary to implement the following procedures (as applicable to the plant design): a) Event specific EPGs or plant specific EOPs b) Functional restoration EPGs or plant specific EOPs c) Plant AOPs
4.5 Type E variables Type E variables are those variables required for use in determining the magnitude of the release of radioactive materials and continually assessing such releases. The selection of these variables shall include, but not be limited to, the following:
a) Monitor the magnitude of releases of radioactive materials through identified pathways (e.g., secondary safety valves, and condenser air ejector).
b) Monitor the environmental conditions used to determine the impact of releases of radioactive materials through identified pathways (e.g., wind speed, wind direction, and air temperature).
c) Monitor radiation levels and radioactivity in the plant environs.
d) Monitor radiation levels and radioactivity in the control room and selected plant areas where access may be required for plant recovery.
4.6 Documentation of selection bases Documentation shall be developed and maintained for the selection bases of the accident monitoring variables consistent with the plant LBD.IEEE 497 pdf download.IEEE 497-2002 pdf download