2.8.2.16. Block 65 — FUELIN — Channel-Dependent Fuel Input

1

FSPEC

Fuel-pin failure criterion, threshold value. IERSTP

(See also FMELTM and PCFAIL).

See MFAIL.

2

FMELTM

The minimum fuel melt fraction that must exist at the failure node before PLUTO2 or LEVITATE is allowed to be called.

Suggested value: 0.2 (must be input > 0).

3

DENS

kg/m^3

Liquid cladding density at the liquidus.

4

AE

1/K

Coefficient of linear expansion of solid cladding (=1/3 volume coefficient).

5

RHOCD

1/K

Volumetric coefficient of expansion for liquid cladding.

6

VISMC

Pa-s

Viscosity of cladding at liquidus temperature. At higher temperatures,

viscosity= VISMC*EXP( AVISC / TELIQ - AVISC /T).

7

VISTR

Pa-s

Viscosity of cladding at solidus temperature. Between solidus and liquidus,

viscosity=(VISTR-VISMC)* (1-FMELTC)** XVISC + VISMC

where FMELTC is the melt fraction.

8

VISSC

Pa-s

Viscosity of refrozen cladding. This is used as viscosity below solidus.

9

XVISC

Exponent in viscosity equation.

10

CLADFR

Moody friction factor for the molten cladding during turbulent cladding flow over the fuel rod.

11

REBRK

Laminar to turbulent transition Reynolds number for molten cladding flow.

12

GMULTF

Constants in molten cladding and sodium vapor two-phase friction multiplier.

Multiplier = CHOR*(1.0+GMULTF*(1.0-MAX(ALPH, ALPHCR )))

where ALPH is void fraction. The incoherence (time delay) factor is:

CHOR=MAX(0.01,MIN(1.0,(FPS/ FPS0 )** EXPFPS ))

where FPS is the time in full-power seconds since cladding first moved in the channel.

13

ALPHCR

See GMULTF.

14

FPS0

See GMULTF.

15

EXPFPS

See GMULTF.

16

AMELT

Not currently used.

17

CLSTHR

Multiplier for frozen cladding-structure heat transfer.

Suggested value: 1.0.

18

FRACPD

Not currently used.

19

PCFAIL

Pa

Pin cavity pressure at pin failure time. Only necessary if the transient DEFORM calculation is not used (ISSFU2 .NE.1) or if CLAP preceded LEVITATE in this channel. May also be useful for overriding the DEFORM calculated cavity pressure for parametric studies. For PCFAIL < 1, the DEFORM calculated cavity pressure is used in PLUTO and LEVITATE. This is the recommended option when it can be used.

20

AVISC

K

Constant in viscosity equation. (See VISMC).

21

CPC

J/kg-K

Specific heat capacity of molten cladding at the liquidus temperature.

22

FPINAC

Areal fraction of fuel, with enthalpy exceeding the melting threshold of at least FNMELT of the heat of fusion, required to initiate PINACLE ; i.e. for in-pin pre-failure fuel motion to begin. See FNMELT and CPINAC .

Recommended value: 2 radial nodes.

23

CPINAC

Also, at least 3 contiguous axial nodes must satisfy the condition: Molten fuel fraction > FPINAC x CPINAC in order to initiate PINACLE. Recommended value: 0.5.

24

RHOREF

kg/m^3

Reference density for metallic fuel at room temperature (273.15K). See also FPRSTY.

Used by MFUEL (IFUELO = 2).

25

WUREF

Fabricated uranium weight fraction in metallic alloy fuel when MFUEL is used (IFUELO = 2). Also reserved for the SSCOMP model (IFUELO = 1).

Internally, MFUEL will redefine WUREF = 1.0 - WPUREF - WZRREF

26

WPUREF

Fabricated plutonium weight fraction in metallic alloy fuel when MFUEL is used (IFUELO = 2). Also reserved for the SSCOMP model (IFUELO = 1).

27

WZRREF

Fabricated zirconium weight fraction in metallic alloy fuel when MFUEL is used (IFUELO = 2). Also reserved for the SSCOMP model (IFUELO = 1).

28

FPRSTY

As-fabricated volume fraction of fuel porosity. Fabricated fuel density is (1.0 - FPRSTY) * RHOREF.

Used by MFUEL (IFUELO = 2).

29

RAPIDEUT

Rapid eutectic scaling factor for MFUEL (IFUELO = 2). RAPIDEUT > 0.

Default = 1.0.

30

HFMELT

J/kg

Fuel heat of fusion when MFUEL (IFUELO = 2) is used.

Default is determined from IFR Metallic Fuels Handbook data.

When not using MFUEL, see UFMELT.

31-51

DFUELX

Not currently used.

52

FUSLDT

m

Maximum axial displacement of the upper fuel blanket or/and sodium slug above the fuel active top.

53

FUSLMA

kg/pin

Total mass of the upper fuel blanket or/and sodium slug above fuel pin top.

54

BURNFU

at\%

Axially averaged fuel pin burnup for metal fuel pins used in the SSCOMP model (IFUELO = 1). Also used for IFUELM = 2.

= 0, FPDAYS and FLTPOW used to calculate cladding fluence.

> 0, BURNFU determines cladding fluence.

55-198

XPUZR

Post-zone formation plutonium and Zirconium weight fractions in the central zone, followed by those in the middle zone and those in the outer zone.

Not currently used.

199

GASRTM

Not currently used.

200

TIRRFU

K

Cladding steady state irradiation temperature at the top of the fuel region for metal fueled pins. Used in life fraction calculation.

≤ 0, Maximum temperature during steady state at each axial node used.

> 0, And ISSFUE = 0, value applied to each axial node

201-300

DFUELI

Not currently used.