Document: NUREG-0800
Document ID: ab4f353d-c299-479d-ab25-834f97196988
Document Type: srp
Title: CONCRETE AND STEEL INTERNAL STRUCTURES OF STEEL OR CONCRETE
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070326.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.8.3
CFR Part: 
CFR Title: 

Content:
ark III containment system, which utilizes the 13 pressure-suppression concept, the drywell surrounds the reactor coolant system. The lower portion of the drywell is surrounded by the suppression pool which is bounded by the containment shell on the outside and by a weir wall located just inside the drywell wall. A series of vent holes connect the drywell to the suppression pool. In the event of a loss-of-coolant accidentLOCA, the drywell will contain the steam 14 released from the reactor coolant system and, temporarily acting as a pressure-retaining envelope, will channel the steam through the vent holes and into the suppression pool. The pool water will condense the steam, and the energy released to the containment will thus be minimized. Following such a LOCA and before blowdown is completed, the drywell will be subjected to a differential pressure and possibly jet forces, and any structural failure in its boundary would result in steam bypassing the 3.8.3-5 DRAFT Rev. 2 - April 1996 suppression pool and flowing directly into the containment, possibly generating a containment pressure higher than that for which it has been designed. With this functional requirement in mind, the general arrangement and principal features of the drywell are reviewed with emphasis on structural framing and expected behavior under loads. Since the drywell geometrically resembles, to a certain degree, a containment, the descriptive information reviewed is similar to that reviewed for containments as delineated in subsection I.1 of SRP Section 3.8.1. The major components of the drywell that are so reviewed, other than the main body of the drywell, include the bottom vent region, the roof and drywell head, and major penetrations. ii. Weir Wall The weir wall forms the inner boundary of the suppression pool and is located inside the drywell. It completely surrounds the lower portion of the reactor coolant system. The general arrangement and principal features of the weir wall are