Document: NUREG-0800
Document ID: f9d2d9cb-1d13-407e-ad7a-523fff64de06
Document Type: srp
Title: DC POWER SYSTEMS (ONSITE)
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1007/ML100740391.pdf
Revision Date: 2023-06
Chapter: 8
Section ID: 8.3.2
CFR Part: 
CFR Title: 

Content:
ation regarding both power sources and their associated distribution systems, including the batteries, battery chargers, power supply feeders, panel arrangements, loads supplied from each battery, and power connections to the inverters and connections to the instrumentation and control devices of the system. 2. Conformance with the Single-Failure Criterion. In determining the adequacy of this system to meet the single-failure criterion, the reviewer will examine the electrical and physical separation of redundant dc power sources and associated distribution systems to assess the independence between redundant portions of the system. This will include a review of the interconnections between redundant buses, buses and loads, and buses and power supplies; proposed sharing of the dc power system between units at the same site; design criteria and bases governing the installation of electrical cable for redundant portions of the systems; and physical arrangement of redundant switchgear and power supplies. 3. Power Supplies. The staff will review design information and analyses demonstrating the suitability of batteries and battery chargers as dc power supplies and of inverters that convert dc to ac for instrumentation and control power to ensure that they have sufficient capacity and capability to perform their intended functions, including the ability to cope with an SBO event. This will require an examination of (a) the characteristics and design requirements of each load (such as motor horsepower, volt-amp rating, in-rush current, starting volt-amps, and torque), (b) the length of time each load is required, (c) the combined load demand connected to each dc supply during the worst operating conditions, (d) the voltage recovering characteristics of batteries, and (e) the performance characteristic curves (e.g., voltage profile curves, discharge rate curves, and temperature effect curves) that illustrate the response of the batteries to the most severe loading