Document: NUREG-0800
Document ID: e3249d77-0411-430a-9793-06aea8669075
Document Type: srp
Title: FISSION PRODUCT CONTROL SYSTEMS AND STRUCTURES
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070474.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6.5.3
CFR Part: 
CFR Title: 

Content:
76 • structural design of containments (SEB) and systems (MEBEMEB ) 77 • engineered safety feature filter systems (ETSBPERB ) 78 1. Primary Containment Design a. The primary containment design is studied to familiarize the reviewer with the overall construction and anticipated performance capability of the primary containment. Certain parameters and design features, such as design leakage rate, purge/vent systems leakage rate prior to containment isolation, containment free volume, internal fission product cleanup systems, should be noted for later use (see example of worksheet, DRAFT Rev. 3 - April 1996 6.5.3-8 Table 6.5.3-1). The performance capability of the internal fission product cleanup systems (if any) should be verified (see SAR Sections 6.5.1, 6.5.2, and 6.5.4). b. The transient response of the containment pressure following the accident should be studied. Historically, pressurized water reactor (PWR) containment design leakage rates have been reduced by a factor of two at one day into the accident (Ref. 5Regulatory Guide 1.4 ), whereas boiling 79 water reactor (BWR) containment design leakage rates were assumed to 80 be constant for all time periods following the accident (Ref. 6Regulatory Guide 1.3 ). The reviewer should verify with CSBSCSB that these 81 82 modeling assumptions are valid for each case reviewed. For those containments designed to reach subatmospheric pressure at some time less than 30 days after the accident, the CSBSCSB verifies the time required 83 to reach subatmospheric pressure. 2. Secondary Containment and Other Fission Product Control Structures Design a. The design of the secondary containment and other fission product control structures is reviewed to determine how it should be modeled for the dose calculations. The reviewer also ascertains that the applicant has considered the question of potential exfiltration from regions of the secondary containment under varying wind conditions, especially if the structure has a leakage