Document: NRC Regulatory Guide
Document ID: 1731a882-b0c5-418d-b65e-55646c26be5c
Document Type: regulatory_guide
Title: 03/2007
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0703/ML070380553.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.9
CFR Part: 
CFR Title: 

Content:
A trip should be implemented with two or more measurements for each trip parameter with coincident logic provisions for trip actuation. The design of the coincident logic trip circuitry should include the capability to indicate individual sensor trips. The design of the bypass circuitry should include the capability to (1) test the status and operability of the bypass circuits, (2) trigger alarms in the control room for abnormal values of all bypass parameters (common trouble alarms may be used), and (3) manually reset the trip bypass function. The capability to automatically reset the bypass function is not acceptable. Clause 4.5.4(b) of IEEE Std 387-1995, which pertains to retaining all protective devices during emergency diesel generator testing, does not apply to periodic tests [safety injection actuation system (SIAS), combined with SIAS and LOOP, and protective trip bypass] that demonstrate diesel generator system response under simulated design-basis events. 1.9 Clause 4.5.2.2 of IEEE Std 387-1995 should be modified to read as follows: Upon receipt of an emergency start-diesel signal, the automatic control system shall provide automatic startup and automatic adjustment of speed and voltage to a ready-to-load condition in the emergency (isochronous) mode. Rev. 4 of RG 1.9, Page 7 2. Diesel Generator Testing Clauses 3, 5, 6, and 7 of IEEE Std 387-1995 should be supplemented as discussed below. 2.1 Definitions Figure 1 illustrates those components and systems that should be considered to be within the emergency diesel generator boundary when evaluating failures. Systems that support the emergency diesel generator and perform other plant functions are depicted as being outside this boundary. IEEE Std 387-1995 provides similar definitions of components and system boundaries and may also be used as guidance; however, generator breakers should be considered as part of the diesel generator boundary. The following definitions apply to the regulatory positions that