Document: NUREG-0800
Document ID: 9a56a69d-7ff5-45af-9d63-dbefa3dea083
Document Type: srp
Title: TURBINE GENERATOR
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070575.pdf
Revision Date: 2023-06
Chapter: 10
Section ID: 10.2
CFR Part: 
CFR Title: 

Content:
e this review with other branches for their particular areas of responsibility as stated in subsection I. The primary reviewer obtains and uses such input as required to assure ensure that this review procedure is complete. 1. The SAR is reviewed to determine that the system description and piping and instrumentation diagrams (P&IDs) show the turbine generator system. The general arrangement of the TGS and associated equipment with respect to safety-related structures, systems, and components is noted. 2. The reviewer verifies the adequacy of the control and overspeed protection system and determines that: a. Support systems, subsystems, control systems, and alarms and trips will function for all abnormal conditions, including a single failure of any component or subsystem, and will preclude an unsafe turbine overspeed. The in depth defense that is provided by the turbine generator protection system to preclude excessive overspeeds should be designed with diverse protection means. b. For normal speed-load control, the speed governor action of the electrohydraulic control system fully cuts off steam at approximately 103% of rated turbine speed by closing the control, and intercept valves. c. A mechanical overspeed trip device is provided that will actuate the control, stop, and intercept valves at approximately 111% of rated speed. d. An independent and redundant backup electrical overspeed trip circuit is provided that senses the turbine speed by magnetic pickup and closes all valves associated with speed control at approximately 112% of rated speed. This backup electrical overspeed trip system may utilize the same sensing techniques as the electrohydraulic control system. However, the circuitry is reviewed to determine that the control signals from the two systems are isolated from, and independent of, one another. 3. The main steam stop, control, reheat stop, and intercept valving arrangements and valve closure times are reviewed to ensure that no single valve