ML20128L554
| ML20128L554 | |
| Person / Time | |
|---|---|
| Site: | 05200003 |
| Issue date: | 10/09/1996 |
| From: | Huffman W NRC (Affiliation Not Assigned) |
| To: | Liparulo N WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP. |
| References | |
| NUDOCS 9610150119 | |
| Download: ML20128L554 (5) | |
Text
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October 9,1996 Mr. Nicholas J. Liparulo, Manager Nuclear Safety and Regulatory Analysis Nuclear and Advanced Technology Division Westinghouse Electric Corporation P.C. Box 355 Pittsburgh, Pennsylvania 15230
SUBJECT:
EQUATIONS USED FOR AP600 CONTAINMENT AEROSOL REMOVAL CALCULATIONS
Dear Mr. Liparulo:
On July 17, 1996, Westinghouse was provided with an NRC contractor (Sandia National Laboratories) technical evaluation report entitled " Monte Carlo Uncertainty Analysis of Aerosol Behavior in the AP600 Reactor Containment."
Subsequently, Westinghouse requested information on the equations used to support the report conclusion concerning thermophoretic deposition of aerosols on the containment shell.
Per the Westinghouse request, enclosed is a summary of the gas phase mass and heat transfer equations used in the report.
If you have any questions regarding this matter, you can contact me at (301) 415-1141.
Sincerely, original signed by:
William C. Huffman, Project Manager Standardization Project Directorate Division of Reactor Program Management Office of Nuclear Reactor Regulation Docket No.52-003
Enclosures:
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Mr. Nicholas J. Liparulo Docket No.52-003 Westinghouse Electric Corporation AP600 cc: Mr. B. A. McIntyre Mr. Ronald Simard, Director Advanced Plant Safety & Licensing Advanced Reactor Programs Westinghouse Electric Corporation Nuclear Energy Institute Energy Systems Business Unit 1776 Eye Street, N.W.
P.O. Box 355 Suite 300 i
Pittsburgh, PA 15230 Washington, DC 20006-3706 Mr. John C. Butler Ms. Lynn Connor j
Advanced Plant Safety & Licensing Doc-Search Associates Westinghouse Electric Corporation Post Office Box 34 Energy Systems Business Unit Cabin John, MD 20818 Box 355 Pittsburgh, PA 15230 Mr. James E. Quinn, Projects Manager LMR and SBWR Programs Mr. M. D. Beaumont GE Nuclear Energy Nuclear and Advanced Technology Division 175 Curtner Avenue, M/C 165 Westinghouse Electric Corporation San Jose, CA 95125 One Montrose Metro 11921 Rockville Pike Mr. Robert H. Buchholz Suite 350 GE Nuclear Energy Rockville, MD 20852 175 Curtner Avenue, MC-781 San Jose, CA 95125 Mr. Sterling Franks U.S. Department of Energy Barton Z. Cowan, Esq.
NE-50 Eckert Seamans Cherin & Mellott 19901 Germantown Road 600 Grant Street 42nd Floor Germantown, MD 20874 Pittsburgh, PA 15219 Mr. S. M. Modro Mr. Ed Rodwell, Manager Nuclear Systems Analysis Technologies PWR Design Certification i
Lockheed Idaho Technologies Company Electric Power Research Institute Post Office Box 1625 3412 Hillview Avenue Idaho Falls, ID 83415 Palo Alto, CA 94303 Mr. Frank A. Ross Mr. Charles Thompson, Nuclear Engineer U.S. Department of Energy, NE-42 AP600 Certification Office of LWR Safety and Technology NE-50 19901 Germantown Road 19901 Germantown Road Germantown, MD 20874 Germantown, MD 20874 l
A. GAS PHASE HEAT AND MASS TRANSFER f
An important feature of the AP600 reactor containment is the condensation heat transfer to the containment shell. This heat and mass transfer not only prevents excessive pressurization of the vulnerable steel contalament, it also provides diffusiophonetic and tAssupi-tic forces for the natural deposkion of radioactive aerosols from the containment atmosphere under accident conditions. The model of this heat and mass transfer used in our studies of amosol behavior is described in detail, including appropriate citations of retrievable, archival literature, in the documentation of our work submitted to you and provided to Westinghouse. The model is a fully-coupled turbulent model of condensation beat and mass transfer developed by Corradini
[4). We adopted such a sophisticated model because our analyses of aerosol deposition on the containment shellincluded turbulent deposition as well as thermophoretic and diffusiophoretic deposition. It is, however, tme that the thermal hydraulics of thd miniv.ptwe in the AP600 containment is not especially well understood. The possibility of atmospheric stratification must still be considered in any safety assessment of the reactor design. Por the purpuses of the comparima of aerosol behr.vior calculations, it was felt that the natural convection modeling was quite an adequate representation of the lumped parameter model of thermal hydraulics that was the basis of the NAUAHYOROS calculations while still providing the description of turbulence seeded to augment diffusive deposition.
The boundary conditions for the 3BE accident provided as input to the calculational exercise included the rate of steam condensation on the shell, m(H O), the total heat transfer to 2
the containment shell, Q', and the mole fraction steam in the atmosphere, X(H O), as well as the 2
temperature and pressure of the bulk containment atmosphere. The geometrical data input to the cxercise included the surface area available for condensation, A. The condensation heat and mass transfer model was used to calculate the heat transfer coefficient, h, and the mass transfer coefficient, k.These quantities are used to calculate, among other things, the thermal and m
concentration gradients at the containment surface that are used in the analyses of thermophoretic deposition:
I h* AT = Q'/A - AH(fg)m(H OyA = k VT 2
g m(H 0VA = 2k,* (P (H O)- P,,g(T - AT)}/R(2T -AT) 2 b 2 b
b
( = k /h*
g k,' = kyn[(+1)/(
h* = hIn[c+1Fc j
Nu s hUk, = 0.0295 Gr" Pr/(1+0.494Pr
}"#
Enclosure
..=,
Sh = k /T= 0.0188/Re Sc m
Re a p Np, g
3 2 2
Or=gATI p f,g T g
where:
AT = difference between the bulk containment atmosphere temperature, T, and b
the containment shell surface temperature, AH(fg) = latent heat of steam condensation, k = thermal conductivity of the gas adjacent to the shell surface, g
VT = temperature gradient adjacent to the shell surface, P (H O) = partial pressure of steam in the bulk containment atmosphere, b2 R = universal gas constant, P,,g(T) = saturation partial pressure of steam at temperature T, T = E(1)(p /p L)Gr /2/p+0.494Pr ]*
gg Pr (1+0.494Pr )I 6 = s(2) UOr"I l
( = boundan layer thickness.
L = surface length, Nu = Nusselt number, Sh = Sherwood number, Or = Orashoff number, Sc = Schmidt number, C = heat capacity of the gas, p
l 1
l ll I
.. +
s, p,= viscosity of the sas.
p, = hsity he gas, Pr-Prandt! number, G = m(H O) C /Ah, and 2
p
( = [P,.t(T -AT)- P (H O)]/[P-P (T - AT)).
b b 2 sat b Fairlyinvolved expressions for the propenies of gaseouk mixtum of H 0,0, and N are 2
2 2
used in the Monte Carlo analysis model. These expressions are not reproduced here, but are available elsewhere.
The turbulent natural convection model hypothesizes the existence of a profile for the velocity in the vertical direction adjacent to the containment shell:
V, = P(y/6)#(1-y/6)#
whers:
V = mtical velocity, x
T = coefficient, y = distance from the shell, and 6 = parameter.
Thus, the velocity is zero at the containment shell and at a distance y=6 from the containment i
shell. A velocity maximum occurs at about a distance y=6/29. The model provides definitions of the paramotors 6 mu1P.
The parameter 6 in the Corradini model may be the cause of some conftsion. In this model the parameter is used to characterize the velocity distribution. In the conduction description of the cMaution heat transfer adopted for the analyses done by Westinghouse, the boundary layer thickness is denoted also by the symbol 6. Though the symbols are the same they denote two rather completely different quantities. The 6 in the Westinghouse model is obtained, apparently, frorn the thermal gradient at the surface of the containment shell:
sr/dy= AT/6 As shown above, a boundary layer thickness, (, can also be denned in the Corradini model though thir thickness is not really used in any of th* modeling done for the Monte Carlo analysis ofmerowlbehavior.
t
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