Task II.G: ELECTRICAL POWER: Power Supplies for Pressurizer Relief Valves, Block Valves, and Level Indicators

The objective of this task was to increase the reliability and diversification of the electrical power supplies for certain safety-related equipment.

ITEM II.G.1: POWER SUPPLIES FOR PRESSURIZER RELIEF VALVES, BLOCK VALVES, AND LEVEL INDICATORS

DESCRIPTION

This TMI Action Plan[1] item called for licensees to develop and implement procedures and modifications to upgrade motive and control components to safety-grade criteria. Motive and control components of PORVs and PORV block valves were to have the capability of being supplied either from the offsite power source or from the emergency power source when offsite power was not available. Motive and control power connections to the emergency buses for the PORVs and their associated block valves were to be through devices that had been qualified in accordance with safety-grade requirements. The pressurizer level indication instrument channels were to be powered from the vital instrument buses that had the capability of being supplied either from the offsite power source or from the emergency power source when offsite power was not available.

CONCLUSION

This item was clarified in NUREG-0737[2] and requirements were issued.