Document: NUREG-0800
Document ID: 1dda396e-398a-4b85-aa13-c5c1dbf82bc2
Document Type: srp
Title: MINIMUM CONTAINMENT PRESSURE ANALYSIS FOR EMERGENCY CORE COOLING SYSTEM
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052340670.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6.2.1.5
CFR Part: 
CFR Title: 

Content:
, and until such time (i.e., at the operating license review) that a complete identification of available heat sinks can be made. This simpli- fied approach has also been followed for operating plants by licensees complying with Section 50.46(a)(2) of 10 CFR Part 50. For such cases, and for construction permit reviews, where a detailed listing of heat sinks within the containment often 6.2.1.5-5 Rev. 2 - July 1981 cannot be provided, the following procedure may be used to model the passive heat sinks within the containment: (1) Use the surface area and thickness of the primary containment steel shell or steel liner and associated anchors and concrete, as appropriate. (2) Estimate the exposed surface area.of other steel heat sinks in accordance with Figure 2 and assume an average thickness of 3/8 inch. (3) Model the internal concrete structures as a slab with a thickness of one foot and exposed surface of 160,000 ftW. The heat sink thermophysical properties that would be acceptable are shown in Table 2. Applicants should provide a detailed list of passive heat sinks, with appropriate dimensions and properties. b. Heat Transfer Coefficients The following conservative condensing heat transfer coefficients for heat transfer to the exposed passive heat sinks during the blowdown and post-blowdown phases of the loss-of-coolant accident should be used (see Figure 2): (1) During the blowdown phase, assume a linear increase in the condensing transfer coefficient from h . 8 Btu/hr-ftW- 0F, at t = 0, to a peak value four times gmalfvthan the maximum calculated condensing heat transfer coefficient at the end of blowdown, using the Tagami correlation (Ref. 2), 7. 0.62 hm = 7.25 Vt p where hmax = maximum heat transfer coefficient, Btu/hr-ft2-0F Q = primary coolant energy, Btu V = net free containment volume, ft3 tp = time interval to end of blowdown, sec. (2) During the long-term post-blowdown phase of the accident, characterized by low turbulence in the containment atmosphere,