Document: NUREG-0800
Document ID: 545a669a-51a1-4b1f-9d90-78ee08ca0845
Document Type: srp
Title: COMBUSTIBLE GAS CONTROL IN CONTAINMENT
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070463.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6.2.5
CFR Part: 
CFR Title: 

Content:
e short time period involved. The equations are equivalent to the afterheat decay curve in BTP ASBSPLB 9-2 over the times of interest for post-accident hydrogen generation. Sc(t) ApBC(t) 12×3.15×107 DRAFT Rev. 3 - April 1996 6.2.5-20 It should also be noted that the COGAP formulation overpredicts the radiolytic hydrogen generation by a small amount due to a "double-counting" of the gamma energy of those fission products assumed to be released from the fuel rods. Hydrogen generation due to aluminum corrosion is normally considered only when additives are used in the cooling solution. When applicable, gas production is governed by the following expression: Where S (t) = hydrogen production rate, lb-mole/sec (0.4536 kg-mole/sec) . c 65 A = surface area of aluminum, ft , (0.0929 m ) . 2 2 66 p = aluminum density, lb/ft (multiply density in lb/ft by 16.01846 to obtain density in kg/m ) . 3 3 3 67 B = lb-moles (0.4536 kg-moles) of hydrogen per lb (0.4536 kg) of aluminum 68 69 C(t) = aluminum corrosion rate, in/year (multiply corrosion rate in in/year by 2.540 to obtain corrosion rate in cm/year) . 70 The aluminum corrosion rate has been described by an exponential fit in COGAP to account for an increased rate due to high temperatures early in the accident followed by a constant rate for the remaining period of the analysis. The chemical relationship by which hydrogen is formed has been assumed to be: 2 Al + 3 H O = 3 H + Al O 2 2 2 3 1 lb (0.4536kg) Al = 0.111 lb (0.0503 kg) H 71 72 2 1 lb (0.4536kg) Al = 0.0555 lb-mole (0.02517 kg-mole) H 73 74 2 therefore, B = 0.0555 lb-mole H /lb Al (0.02517 kg-mole H /0.4536 kg Al) 2 2 75 Zinc corrosion is treated in a similar fashion. 6.2.5-21 DRAFT Rev. 3 - April 1996 COGAP INPUT REQUIREMENTS COGAP has been developed to minimize the required input information. All data associated with the power decay profile have been incorporated into the program and need not be entered. The major input requirements are: 1. Reactor power level,