Document: NRC Regulatory Guide
Document ID: 8322a959-849d-4ec6-926e-1f30ed96d71f
Document Type: regulatory_guide
Title: Periodic Testing of Protection System Actuation Functions (Rev. 0)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0833/ML083300530.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.22
CFR Part: 
CFR Title: 

Content:
eactor trip, containment isolation, or emergency coolant injection. The following are examples of actuated equipment: an entire control rod and its release mechanism, a containment isolation valve and its operator, and a safety injection pump and its prime mover. C. DISCUSSION One function of the protection system is to initiate the operation of systems and components important to safety. It is required that the protection system be designed to permit periodic testing of its ability to perform these initiation functions when the reactor is in operation. Based on the review of several applications for construction permits and operating licenses, the regulatory staff has concluded that the preferable method of implementing this requirement is to design the protection system such that - the actuation devices and actuated equipment are periodically tested with the protection system during reactor operation. Generally it has been industry practice to include the actuation devices in the periodic tests of that portion of the protection system used to initiate reactor trip. Early designs did not provide this same degree of testability in those portions of the protection system used to initiate the operation of engineered safety features, standby power supplies, and other supporting systems. It is recognized that providing the capability to test the actuation devices for these latter systems can present different design problems. Nevertheless, General Design Criterion 21 requires the same high degree of inservice testability in all portions of the protection system. In the case of some engineered safety feature systems, testing the operation of the entire group of actuated equipment associated with a protective function may damage plant equipment or disrupt reactor operation. In these cases, acceptable methods of including the actuation devices in periodic tests of the protection system, while avoiding the undesirable effects of operation of the actuated equipment, are: (1)