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:
of the some of the safety relief valves to perform as the Automatic Depressurization System should be described in the DD. However, details of a components design, such as the internal workings of the MSIVs and SRVs, need not be included in the design description because this could limit the COL applicant or licensee to a particular make and model of a component. If the results of the PRA indicate that a particular component or function of a system is risk significant, that component or function should be described in the DD. Any features such as flow limiters, backflow DRAFT Rev. 0 - April 1996 14.3-40 protection, surge tanks, severe accident features, etc. should be described in the DD as follows: Flow limiting features for high-energy line breaks (HELBs) outside of containment - The minimum pipe diameter should be confirmed because these features are needed to directly limit/mitigate Design Basis Events such as pipe breaks. Lines less than 1 inch (e.g., instrument lines) need not included because their small size limits the effects of HELBs outside containment. Keep Fill systems - These should be included in the design description when needed for the direct safety function to be achieved without the damaging effects of water hammer. On-line Test Features - Some systems/components 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 should be described in the DD. Filters - Filters that are required for a safety function (such as Control room HVAC radiation filtering) should be in the design description. The basic configuration ITAAC will check that the filter exists, but need not test the filter performance. Surge Tank - The capacity of the surge tank should be verified if the tank is needed to perform the direct safety function. For example, in the case of the RCW surge tank a certain volume is required to meet the