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

1

AFR

Liquid slug friction factor coefficients.

Default values when IFRFAC < 2: AFR = 0.1875, BFR = -0.2.

Required input when IFRFAC = 2.

2

BFR

see AFR. Required input when IFRFAC = 2.

3

C1

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

4

C2

See C1

5

C3

See C1

6

DWMAX

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

Default: = 0.2

7

RELAM

Maximum Reynolds number for flow in the laminar regime.

Default value when IFRFAC < 2: RELAM = (AFLAM/AFR)**(1/(1 + BFR)) to ensure continuity at the turbulent/laminar boundary.

Required input when IFRFAC = 2.

8

AFLAM

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

Suggested value: 64. Required input when IFRFAC = 2.

9

RETRAN

Minimum Reynolds number for flow in the turbulent regime. Required input when IFRFAC = 2.

10

C1TRAN

Transition regime friction factor coefficient. Default value: 1/3

11

C2TRAN

Transition regime friction factor coefficient. Default value: 7.0

12

C3TRAN

Transition regime friction factor coefficient. Default value: 1/3

13-46

DUM000

Not currently used.

47

W0

kg/s

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

48-63

XKORI (K,M)

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)

64

XKORGD

Orifice coefficient for spacer grids in pin. See NGRDSP.

65

DZIAB

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.

66

DZIAT

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.

67

THETA1

= 0.5 normally; = 0.0 for implicit calculation.

68

THETA2

= 0.5 normally; = 1.0 for implicit calculation.

69

DTLMAX

K

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

70

DTVMAX

K

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

71

DZIMAX

m

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

72

HCOND

W/m^2-K

Condensation heat-transfer conductance of coolant.

73

SLMIN

m

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

74

TUPL

K

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

75

WFMIN

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).

76

WFMINS

m

Minimum film thickness on structure. Default: WFMIN

77

WFS00

m

Initial film thickness on structure. Default: WF0.

78-80

FRACP

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

81-83

FRUPT

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

84

WF0

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.

85-104

TFIS

Not currently used. (I)

105-124

PFIS

Not currently used. (I)

125-144

ZFISU

Not currently used. (I)

145-162

ZFISD

Not currently used. (I)

163

DTSWCH

K

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

Default: 5 K.

164

DTSI

K

Superheat for bubble formation near a liquid-vapor interface.

165

DTS

K

Superheat before any sodium vapor bubble can be formed.

166

RESMLT

Not currently used.

167

TEMDLT

Not currently used.

168

AFRV

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

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

169

BFRV

see AFRV

170

XMINL

m

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

171

DTCMIN

s

Minimum coolant time step size before boiling.

Suggested value: 1.0E-6.

172

WFMIND

m

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

Suggested value: 1.0E-7

173

WFMNSD

m

Minimum structure film thickness after IFILM nodes have dried out.

Suggested value: 1.0E-7

174

FVAPM

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

=0, For single-phase friction factor.

=1, For two-phase friction factor.

175

AFRF

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

176

BFRF

Liquid film friction factor coefficient. Default: -0.25.

177

TPDMIN

s

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

178

DTACCL

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.

179

REFLAM

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

180

AFFLAM

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

181

AGSRLS

m^2

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

182

GASKOR

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

183

PGRMIN

Pa

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

184

GASMW

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

185

HEBOIL

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

186-188

TMFAIL

s

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

189

UACH1

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:

190

UACH2

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.

191

REORFT

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

192

FLSWCH

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

193

RELAMV

Vapor Reynolds number for switch from laminar to turbulent.

194

AFLAMV

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

195

FLODTM

s

Film flooding time. Only used if IFLOOD = 1.

196

QEMAX

W/m^2

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

DETAILED COOLANT SUB-CHANNEL MODEL

197-200

UACHM1 (K)

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.

201-204

UACHM2 (K)

See UACHM1.

Reserved for the detailed coolant sub-channel model.

205-208

ALATRL (K)

m

ALATRL Coolant lateral flow area per pin per unit height.

Reserved for the detailed coolant sub-channel model.

209-212

XKLAT (K)

Lateral flow orifice coefficient.

Reserved for the detailed coolant sub-channel model.

213

DPLTLM

Pa

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

Reserved for the detailed coolant sub-channel model.

214

XKSWRL

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.

215

DTNUL1

s

Time step for the single sub-assembly null transient.

Reserved for the detailed coolant sub-channel model.

216

EPSFLW

kg/s

Iteration convergence criterion, flow rates

Reserved for the detailed coolant sub-channel model.

217

EPSTMP

K

Iteration convergence criterion, coolant temperatures.

Reserved for the detailed coolant sub-channel model.

218

EPSPRS

Pa

Iteration convergence criterion, coolant pressures.

Reserved for the detailed coolant sub-channel model.

219

XCMPRS

Compressibility multiplier for the mass conservation equation. Default = 1.0

Reserved for the detailed coolant sub-channel model.

220

XLINRT

m

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

Reserved for the detailed coolant sub-channel model.

221-300

DUMCOO

Not currently used.