Document: NUREG-0800
Document ID: f03d2c71-27a1-41fd-9362-1e62c6142e13
Document Type: srp
Title: Containment Systems and Severe Accidents (Tier 1)
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070653.pdf
Revision Date: 2023-06
Chapter: 14
Section ID: 14.3.11
CFR Part: 
CFR Title: 

Content:
D Tier 2, with specific references to the system ITAAC where the key parameters from these analyses are verified. This is discussed further in Appendix A to this SRP section. DRAFT Rev. 0 - April 1996 14.3-46 4. ON-LINE TEST FEATURES Some systems have special provisions for on-line test capability which is critical to demonstrate its capability to perform the direct safety function. An example is an ECCS test loop. These on-line test features will be verified by ITAAC. 5. SURGE TANKS The capacity of a surge tank will be verified if the tank is needed to perform the direct safety function. For example, for BWRs, a certain RCW surge tank volume is required to meet the specific system leakage assumptions. 6. SPECIAL CASES FOR SEISMIC QUALIFICATION There may be some non-safety equipment that requires special treatment because of its importance to safety. An example is the seismic analysis of the ABWR main steam piping that provides a fission product leakage path to the main condenser and allows the elimination of the traditional main steam isolation valve leakage control system. 7. INITIATION LOGIC If a system/component has a direct safety function it typically receives automatic signals to perform some action. This includes start, isolation, etc. The system ITAAC capture these aspects related to the direct safety function. The entire logic and combinations are not tested in the system ITAAC because the overall logic is checked in the I&C ITAAC for the safety system logic. 8. INTERLOCKS Interlocks needed for direct safety functions will be included in the system design description and ITAAC. Examples include the interlocks to prevent ISLOCA and an interlock that switches the system or component from one mode to a safety function mode. Other interlocks that are more equipment protective in nature, are only in the DCD Tier 2. All of the interlocks are not tested in the system ITAAC because the overall logic is checked in the I&C ITAACs for the safety system logic. 9.