2.8.2.15. Block 64 — COOLIN — Channel-Dependent Coolant Input

AFR

1

Liquid slug friction factor coefficients.

Default values: AFR = 0.1875, BFR = -0.2.

BFR

2

see AFR

C1

3

Coefficients in convection heat-transfer coefficient equation:

Hc = Kc*(C1*(Re*Pr)**C2 + C3)/Dh

(Lyon-Martinelli correlation).

Kc: coolant thermal conductivity

Re: Reynolds number

Pr: Prandtl number

Dh: channel hydraulic diameter

C2

4

See C1

C3

5

See C1

DWMAX

6

Maximum fractional change per heat-transfer step in coolant flow rate before boiling.

Default: = 0.2

RELAM

7

Reynolds number for switch between turbulent friction factor and laminar friction factor.

AFLAM

8

Laminar friction factor = AFLAM/Re, where Re is the Reynolds number.

Suggested value: 64.

DUM000

9-46

Not currently used.

W0

47

kg/s

W, steady-state coolant flow rate per fuel-pin.

XKORI (K,M)

48-63

Orifice coefficients K < 8:

K = 1,2, …, NREFB+NREFT+1:

XKORI(K,M) is the coefficient at the bottom of zone K.

K = NREFB+NREFT+2:

XKORI(K,M) is the coefficient at the top of the subassembly.

M = 1, for upward flow.

M = 2, for downward flow.

Example: ((K=1,2,…),M=1,2)

XKORGD

64

Orifice coefficient for spacer grids in pin. See NGRDSP.

DZIAB

65

1/m

Effective coolant inertial term below the subassembly inlet.

Suggested value: D/(2*ACC), where D is the subassembly inlet hydraulic diameter and ACC is the inlet cross-sectional flow area per pin.

DZIAT

66

1/m

Effective coolant inertial term above the subassembly outlet.

Suggested value: D/(2*ACC), where D is the subassembly outlet hydraulic diameter and ACC is the outlet cross-sectional flow area per pin.

THETA1

67

= 0.5 normally; = 0.0 for implicit calculation.

THETA2

68

= 0.5 normally; = 1.0 for implicit calculation.

DTLMAX

69

K

Maximum temperature change/coolant time step in liquid. Suggested value: 15.

DTVMAX

70

K

Maximum temperature change/coolant time step in vapor. Suggested value: 50.

DZIMAX

71

m

Maximum interface motion/coolant time step. Suggested value: 0.1.

HCOND

72

W/m^2-K

Condensation heat-transfer conductance of coolant.

SLMIN

73

m

Minimum initial liquid slug length. Recalculated as cladding melting is approached. Default: 0.02.

TUPL

74

K

Temperature of liquid coolant re- entering the subassembly from above. Used only with PRIMAR-1.

WFMIN

75

m

Minimum film thickness on cladding. Burnout is assumed for film thickness less than WFMIN. For static film option WFMIN is approximately 0.667*WF0. Film motion model is not operational. Default: 1.0E-7. (See WFMIND and WFMNSD).

WFMINS

76

m

Minimum film thickness on structure. Default: WFMIN

WFS00

77

m

Initial film thickness on structure. Default: WF0.

FRACP

78-80

Fraction of pins in this channel in failure group M. See IGASRL. (M)

FRUPT

81-83

Cladding life fraction for cladding failure in group M. See IGASRL. (M)

WF0

84

m

Initial thickness of liquid coolant film left on the cladding in a voided region. Suggested value: That thickness corresponding to a total liquid volume fraction of 0.15 (spread between cladding and structure films) in the voided region.

TFIS

85-104

Not currently used. (I)

PFIS

105-124

Not currently used. (I)

ZFISU

125-144

Not currently used. (I)

ZFISD

145-162

Not currently used. (I)

DTSWCH

163

K

Switch from pre-boiling to boiling when coolant temperature is within DTSWCH of boiling.

Default: 5 K.

DTSI

164

K

Superheat for bubble formation near a liquid-vapor interface.

DTS

165

K

Superheat before any sodium vapor bubble can be formed.

RESMLT

166

Not currently used.

TEMDLT

167

Not currently used.

AFRV

168

Vapor friction factor = AFRV*(Re)** BFRV.

Default values: AFRV = 0.316, BFRV = -0.25.

BFRV

169

see AFRV

XMINL

170

m

Vapor pressure gradient calculation starts when vapor bubble length is XMINL. Default: 0.05.

DTCMIN

171

s

Minimum coolant time step size before boiling.

Suggested value: 1.0E-6.

WFMIND

172

m

Minimum cladding film thickness after IFILM film nodes have dried out.

Suggested value: 1.0E-7

WFMNSD

173

m

Minimum structure film thickness after IFILM nodes have dried out.

Suggested value: 1.0E-7

FVAPM

174

Fraction of two-phase friction factor to be used in vapor calculation.

=0, For single-phase friction factor.

=1, For two-phase friction factor.

AFRF

175

Liquid film friction factor coefficient. Friction factor = AFRF * (Re) ** BFRF. Default: 0.316.

BFRF

176

Liquid film friction factor coefficient. Default: -0.25.

TPDMIN

177

s

Minimum coolant time step size during boiling. Suggested value: 1.0E-6.

DTACCL

178

s

Acceleration term is dropped from the momentum equation for Na vapor in a pressure drop bubble if the time step size is less than DTACCL. Suggested value: 1.0E-5.

REFLAM

179

Reynolds number for switch to laminar friction factor for liquid film.

AFFLAM

180

Laminar film friction factor = AFFLAM/Re, where Re is the Reynolds number.

AGSRLS

181

m^2

Flow area between gas plenum and rupture point, used only if IGASRL = 1.

GASKOR

182

Orifice coefficient between gas plenum and rupture point, used only if IGASRL =1.

PGRMIN

183

Pa

Shut off gas release when plenum pressure falls below PGRMIN, used only if IGASRL = 1.

GASMW

184

Molecular weight of plenum gas. Suggested value: 100-130.

HEBOIL

185

Boiling heat transfer enhancement factor. Suggested value: 1.0 for Na, 50-100 for D2O.

TMFAIL

186-188

s

Pin failure time for pin group M for the gas release model. Used only if IGASRL=2. (M)

UACH1

189

Channel-to-channel heat flow per pin per unit height at axial node J from coolant in channel I to coolant in channel I+1 is calculated as:

UACH2

190

Q(J)=(UACH1(I)*K(J)+UACH2(I)*C(J)*(W(I)+W(I+1)))*(T(I,J)-T(I+1,J))

Where

T(I,J) = Coolant temperature

K(J) = Coolant thermal conductivity

C(J) = Coolant specific heat

W(I) = Coolant flow rate

Note: UACH1 and UACH2 are used only if JJMLTP is not equal to 0.

REORFT

191

Transition Reynolds number for the inlet orifice. The inlet orifice goes laminar for smaller Reynolds numbers. Used only if JJMLTP > 0.

FLSWCH

192

Switch to lumped node coolant temperature treatment when |W/W0| < FLSWCH. Only in reflector zones. Only in the pre-boiling calculation.

RELAMV

193

Vapor Reynolds number for switch from laminar to turbulent.

AFLAMV

194

Vapor laminar friction factor = AFLAMV/Re. | | |

FLODTM

195

s

Film flooding time. Only used if IFLOOD = 1.

QEMAX

196

W/m^2

Maximum heat flux from clad to vapor in a voided region. Default: no limit.

DETAILED COOLANT SUB-CHANNEL MODEL

UACHM1 (K)

197-200

Coolant sub-channel to sub-channel heat flow per pin per unit height at axial node J from channel I to channel L is calculated as:

Q(J)= (UACHM1*k(J)+UACHM2*C(J)*(W(I)+W(L+1))) *(T(I,J)-T(L,J))

where

T(I,J) = coolant temperature

k(J) = coolant thermal conductivity

C(J) = coolant heat capacity

W(I) = coolant flow rate

L = the Kth channel that channel I is in contact with

Note: UACH1 and UACH2 were used for a previous multiple pin model. UACHM1(K) and UACHM2(K) are used for the current detailed coolant sub-channel model.

Reserved for the detailed coolant sub-channel model.

UACHM2 (K)

201-204

See UACHM1.

Reserved for the detailed coolant sub-channel model.

ALATRL (K)

205-208

m

ALATRL Coolant lateral flow area per pin per unit height.

Reserved for the detailed coolant sub-channel model.

XKLAT (K)

209-212

Lateral flow orifice coefficient.

Reserved for the detailed coolant sub-channel model.

DPLTLM

213

Pa

Lateral flow goes laminar if pressure difference between adjacent sub-channels is less than DPLTLM.

Reserved for the detailed coolant sub-channel model.

XKSWRL

214

1/m

Swirl flow between sub-channels = XKSWRL*DZ*WAV

DZ = axial node height

WAV = average of sub-channel axial coolant flow rates

See also KSWIRL.

Reserved for the detailed coolant sub-channel model.

DTNUL1

215

s

Time step for the single sub-assembly null transient.

Reserved for the detailed coolant sub-channel model.

EPSFLW

216

kg/s

Iteration convergence criterion, flow rates

Reserved for the detailed coolant sub-channel model.

EPSTMP

217

K

Iteration convergence criterion, coolant temperatures.

Reserved for the detailed coolant sub-channel model.

EPSPRS

218

Pa

Iteration convergence criterion, coolant pressures.

Reserved for the detailed coolant sub-channel model.

XCMPRS

219

Compressibility multiplier for the mass conservation equation. Default = 1.0

Reserved for the detailed coolant sub-channel model.

XLINRT

220

m

Inertial length for sub-channel to sub-channel flow.

Reserved for the detailed coolant sub-channel model.

DUMCOO

221-300

Not currently used.