Document: NUREG-0800
Document ID: 9c59dff8-9325-43e2-8e81-843a0f6b4b2f
Document Type: srp
Title: and Regulatory Guide 1.189.
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0327/ML032740044.pdf
Revision Date: 2023-06
Chapter: 9
Section ID: 9.5.1
CFR Part: 
CFR Title: 

Content:
ons is not possible. Because of its physical configuration, the control room is excluded from this approach, provided an independent alternative shutdown capability that is physically and electrically independent of the control room is included in the design. Evolutionary ALWRs must provide fire protection for redundant shutdown systems in the reactor containment building that will ensure, to the extent practicable, that one shutdown division will be free of fire damage. Additionally, the evolutionary ALWR designers must ensure that smoke, hot gases, or the fire suppressant will not migrate into other fire areas to the extent that they could adversely affect safe shutdown capabilities, including operator actions. 2. Passive Plant Safe Shutdown Condition Revision 4 - October 2003 51 As discussed in SECY-94-084, the definitions of safe shutdown as contained in the Commission’s regulations and guidelines do not address the inherent limitations of passive residual heat removal systems. In General Design Criterion (GDC) 34 of Appendix A to 10 CFR Part 50, the NRC regulations require that the design include a residual heat removal (RHR) system to remove residual heat from the reactor core so that specified acceptable fuel design limits are not exceeded. GDC 34 further requires suitable redundancy of the components and features of the RHR system to ensure that the system safety functions can be accomplished, assuming a loss of offsite power or onsite power, coincident with a single failure. The NRC promulgated these requirements to ensure that the RHR system is available for long-term cooling to ensure a safe shutdown state. Post-fire safe shutdown (for currently operating LWRs) is defined (in Regulatory Guide 1.189) as those conditions specified in the Technical Specifications for Hot Standby [Pressurized Water Reactors (PWRs)], Hot Shutdown [Boiling Water Reactors (BWRs)], and Cold Shutdown. Regulatory Guide 1.139 and Branch Technical Position (BTP) RSB 5-1 specify