Document: NUREG-0800
Document ID: efac696f-0049-4b65-b562-4a813c1d817c
Document Type: srp
Title: STANDBY LIQUID CONTROL SYSTEM (BWR)
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070538.pdf
Revision Date: 2023-06
Chapter: 9
Section ID: 9.3.5
CFR Part: 
CFR Title: 

Content:
ility to shut down the reactor and maintain it in a safe shutdown condition, or (3) the capability to prevent or mitigate the consequences of accidents that could result in potential offsite exposures comparable to the guideline exposures of 10 CFR Part 100. Since the SLCS provides one means to shut down the reactor and maintain it in a safe shutdown condition, the SLCS, and structures housing the SLCS, must be capable of withstanding the effects of natural phenomena. Based on reviewing a number of safety analysis reports (SARs) for light-water reactor nuclear power plants, a seismic design classification system was developed for identifying those plant features that should be designed to withstand the effects of the safe shutdown earthquake (SSE). Regulatory Guide 1.29, Position C.1, states that systems required for safe shutdown, including their foundations and supports, are designated as Seismic Category I and should be designed to withstand the effects of the SSE and remain functional. Compliance with Regulatory Guide 1.29 provides assurance that the SLCS will perform its intended safety function in the event of an earthquake.30 2. Compliance with GDC 26 requires that two independent reactivity control systems of different design principles be provided, with one of the systems being capable of holding the reactor core subcritical under cold conditions. In a BWR, the normal method of reactivity control utilizes control rods, which are capable of maintaining the reactor subcritical, including allowance for a stuck rod, without the addition of any poison to the reactor coolant. The SLCS acts as a emergency backup to the insertion of control rods to provide a diverse means of making the reactor subcritical. Making provisions for the storage of an adequate amount of neutron absorber in solution, along with the capability DRAFT Rev. 3 - April 1996 9.3.5-6 for injection at a rate sufficient to bring the reactor from rated power to cold shutdown (at any time in core