2.8.2.6. Block 12 — POWINA — Power, Decay-Heat, and Reactivity Input

1

POW

W

Steady-state power in the peak axial fuel pin segment. (sum of fuel + cladding + coolant + structure power; See IPOWOP). Note: POW=POWTOT*FRPR/POWSUM where POWSUM=sum over NCHAN channels of (NPIN*NSUBAS*(sum over MZ of PSHAPE)). (See MZ, NCHAN, PSHAPE, NPIN, FRPR, and NSUBAS).

2

GENTIM

s

Prompt neutron lifetime.

3

POWTOT

W

Total reactor power.

4-9

BETADN (L)

Effective delayed neutron fraction for delayed neutron precursor family L. L =1,…,NDELAY.

10-15

DECCON (L)

1/s

Decay constant for delayed neutron precursor family L. L =1, …, NDELAY.

16-21

OLDBDK (L)

Not currently used.

22-27

OLDDKL (L)

Not currently used.

28

OLDBDT

Not currently used.

29-48

PREATB (L)

Transient external reactivity or power table utilized by function PREA for NPREAT > 0. If reactivity is input, entries are in dollars. If power is input, entries are normalized to nominal power (so that for PREATM = 0.0, PREATB = 1.0). L = 1, …, NPREAT.

49-68

PREATM (L)

s

Transient problem times at which values in PREATB table are to be applied. L = 1, …, NPREAT.

69

FRPR

Fraction of total reactor power represented by sum of all channels.

70

FRFLOW

Fraction of total reactor coolant flow represented by sum of all channels.

71

CRDLEN

m

Length of control rod drives washed by outlet sodium, for ICREXP = 1 (single node model). Typical value: 6 m.

72

CRDEXP

1/K

Thermal expansion coefficient of control rod drives. Typical value: 2 x 10^-5.

73

ACRDEX

$/m

Control rod expansion feedback = ACRDEX * DZ + BCRDEX * DZ².

74

BCRDEX

$/m^2

See ACRDEX.

75

CRDMC

J/K

Control rod drive mass times specific heat, for ICREXP = 1. Typical value: 5.6 x 10⁴ J/K.

76

CRDHA

W/K

Control rod drive surface area times heat- transfer coefficient, for ICREXP = 1. Typical value: 2300.

77

UIVOL

m^3

Coolant volume in the upper internal structure region. Typical value: 25. Note: Locations 71 - 77 are only used if ICREXP > 0.

78

RDEXPC

$/K

Coefficient in simple radial expansion feedback model.

79

XMCXAC

XMC/XAC in simple radial expansion feedback model. XMC: Distance from nozzle support point to core midplane. XAC: Distance from nozzle support point to above core load pad.

80-89

SCRTAB

$

Scram reactivity table (See ASCRAM, PSCRAM, GSCRAM).

90-99

SCRTME

s

Times for SCRTAB. Zero time corresponds to TSCRAM+DELSCR, where TSCRAM is the time for scram initiation determined by ASCRAM, PSCRAM, or GSCRAM.

100-179

PRETB2 (K,IPW)

Normalized power table for power type IPW (K = 1-20, IPW = 2-5). Note: Table for type 1 is in PREATB. Total reactor power reported in the output represents only channels assigned to power type 1 and does not include power from channels assigned to power types 2-5.

180-259

PRETM2 (K,IPW)

s

Times for PRETB2 table.

260-289

BETADK (L,IPW)

Decay heat precursor yield for group L in decay heat curve IPW. 1 ≤ L ≤ Min(NDKGRP, 6), 1 ≤ IPW ≤ NPOWDK Only decay heat curves with six or fewer groups may be defined by BETADK. For curves consisting of more terms, see DKBET2.

290-319

DKLAM (L,IPW)

1/s

Decay heat decay constant for BETADK(L,IPW).

320-324

BETAHT (IPW)

Sum of decay heat precursor yields for user-supplied decay heat curve IPW. If BETAHT(IPW) > 0.0, precursor yields for curve IPW are renormalized to BETAHT(IPW). BETAHT applies to precursor yields defined by BETADK or DKBET2.

325-364

POWLVL (K,IPR)

Table of normalized total power for initializing decay power in decay heat region IPR. 1 ≤ K ≤ NPDKST ≤ 8 1 ≤ IPR ≤ Min(NDKREG, 5) NDKREG is the number of decay heat regions as determined internally by the code based on user-supplied decay heat input (see DKFRAC below). Only the first five regions are included in this table (see PWLVL2/PWTIM2 below to specify the remaining regions). Zero values in this table will initialize decay heat based on zero total power. To calculate infinite, steady-state initialization for all regions, set NPDKST to zero.

365-404

POWTIM (K,IPR)

s

Duration (in seconds) of initializing power level POWLVL(K,IPR).

405

PUBYU

Not currently used.

406

HAUIS

W/K

Heat transfer coefficient * area for upper internal structure to hot pool heat transfer. Used for ICREXP > 0.

407

XMCUI

J/K

Mass * specific heat of steel in the upper internal structure region. Used for ICREXP > 0.

LOCATIONS 408-415 USED ONLY IF |IRADEX| > 3

408

SLLMAX

m/m

Maximum allowable slope of subassembly at grid plate with respect to vertical based on subassembly nozzle/grid plate clearances; default: 2.0 x 10^-4.

409

PITCHG

m

Subassembly pitch at the grid at the reference temperature TR .

410

PITCHA

m

Flat-to-flat dimension across the above core load pad at the reference temperature TR.

411

PITCHT

m

Flat-to-flat dimension across the top load pad at the reference temperature TR.

412

RDEXCF

$/m

Radial expansion coefficient for uniform core dilation.

413

TLPRRC

m

Clearance between the top load pad and the restraint ring. Default: 2.54 x 10^-3 m.

414

BNDMM1

1/m

Applied bending moment at the top of the core region, representing the flat-to-flat temperature difference at the outer edge of the active core. Default: 1.4 x 10^-3.

415

BNDMM2

1/m

Applied bending moment in the region above the core, representing the flat-to-flat temperature difference in this region for subassemblies at the outer edge of the active core. Default: 1.4 x 10^-3.

416

TINSRT

s

Time interval over which REAINS dollars of reactivity is inserted. Default: 1.0.

417

REAINS

$

Amount of reactivity to be inserted linearly during time interval TINSRT.

418

TLIMIT

K

Control rod drive line temperature at which insertion of reactivity REAINS is to begin.

LOCATIONS 419-428 USED ONLY IF |IRADEX| > 3

419

DFLTCS

m

Subassembly displacement at the above-core load pad at zero power resulting from creep and irradiation swelling history, positive outward, for subassemblies at the outer edge of active core.

420

DFLTSS

m

Subassembly displacement at the top load pad at zero power resulting from creep and irradiation swelling history, positive outward, for the subassemblies at the outer edge of active core.

421

ACLPRC

m

Clearance between the compacted above-core load pads and the restraint ring at the above-core load pad elevation, if any. If no above-core restraint ring, enter 0.

422

FCDTR1

Nominal steady-state above-core restraint ring temperature, expressed as a fraction of the average coolant temperature rise through the core.

423

FCDTR2

Nominal steady-state top restraint ring temperature, expressed as a fraction of the coolant temperature rise through the core.

424

FCDTRF

Nominal steady-state reflector load pad temperature, expressed as a fraction of the coolant temperature rise through the core.

425

DRCOLL

m

Additional clearance between the subassembly and its load pad, known as a “floating collar”.

426

CRSAC

m

Additional clearance in the interior of the core, or the difference between the actual core radius and the ideal core radius. Default: 6.35 x 10^-4.

427

RR1TC

s

Thermal response time constant for the above-core restraint ring.

428

RR2TC

s

Thermal response time constant for the top restraint ring.

ADDITIONAL INPUT FOR THE DETAILED CONTROL ROD EXPANSION MODEL

REQUIRED FOR ICREXP = 4.

429

RODID

m

Outside diameter of control rod driveline.

430

RODOD

m

Outside diameter of control rod driveline.

431-433

SHRDLN (K)

m

Length of section K of the control rod, section is deleted if zero.

434-436

SHRDID (K)

m

Inside diameter of section of control rod shroud, no shroud assumed if zero.

437-439

SHRDOD (K)

m

Outside diameter of section of control rod shroud, no shroud is assumed if zero.

440

RHOCRD

kg/m^3

Density of control rod structure.

441

HTCPCR

J/kg-K

Heat capacity of control rod structure.

442

CONDCR

W/m-K

Thermal conductivity of control rod structure.

443

VFCRD

Structure volume fraction in driveline core, remainder is sodium.

444

HFILM

W/m^2-K

Film coefficient on outer control rod shroud surface.

445

FLSHRD

kg/s

Flowrate in shroud annulus.

446

AREACR

m^2

Discharge area for segment representing control rod assembly(s).

447

FLOEXP

Exponent on flow in the CRD shroud friction pressure drop equation.

ADDITIONAL INPUT FOR THE DETAILED RADIAL CORE EXPANSION MODEL

REQUIRED FOR |IRADEX| > 3.

448

ACLPEL

m

Elevation of the center of the above-core load pad with respect to the bottom of the fueled region, zone ‘KZPIN’, at the reference temperature TR.

449

TLPEL

m

Elevation of the center of the top load pad with respect to the bottom of the fueled region, zone ‘KZPIN’, at the reference temperature TR.

450

PTCHRA

m

Flat-to-flat dimension across the above-core load pad for subassemblies exterior to the last row of driver subassemblies at the reference temperature TR.

451

PTCHRT

m

Flat-to-flat dimension across the top load pad for subassemblies exterior to the last row of driver subassemblies at the reference temperature TR.

452

RCBARR

m

Core barrel radius at the reference temperature TR.

453

FCDTCB

Nominal steady-state core barrel temperature, expressed as a fraction of the coolant temperature rise through the core.

454

CB2TC

s

Thermal response time constant for the core barrel.

ADDITIONAL INPUT FOR THE EBR-II REACTIVITY FEEDBACK MODEL, |IREACT| = 2

455

YKNF

∆k/(∆n/n)

Fuel number-density coefficient of reactivity.

456

YKHF

∆k/(∆h/h)

Fuel change in reactivity per fractional change in core fuel height.

457

YKNNA

∆k/(∆n/n)

Sodium number-density coefficient of reactivity.

458

YKNSS

∆k/(∆n/n)

Steel number-density coefficient of reactivity.

459

YRCUR

∆k/K

Upper-reflector coefficient of reactivity.

460

YLCLR

∆k/K

Lower-reflector coefficient of reactivity.

461

YRCRR

∆k/K

Radial-reflector coefficient of reactivity.

462

YRCCR

∆k/K

Control-rod-flow coefficient of reactivity.

463

YRCGP

∆k/K

Grid-plate coefficient of reactivity.

464

YRCDOP

∆k

Non-linear Doppler-effect of reactivity.

465

YDELT0

K

Nominal core delta T at full reactor power.

466

YABOW

Coefficient of non-linear core bowing effect. P = B Delta T/Delta T Deg. + A. (See YBBOW).

467

YBBOW

Coefficient of non-linear core bowing effect. P = B Delta T/Delta T Deg. + A. (See YABOW).

468

FCR

Control-rod feedback parameter: 0 ≤ FCR ≤ 1.

469

YTCUT

The normalized core temperature rise below which the bowing feedback is 0. For instance, if YTCUT=0.5, then for core temperature increases that are less than 1/2 of the nominal core temperature rise (103.5 K) reactor feedback due to bowing is 0$.

EXTERNAL SOURCE SPECIFICATION FOR POINT AND SPATIAL KINETICS APPLICATIONS

470

RHOZRO

$

Initial subcritical reactivity for point kinetics external source. =0, No external source. <0, Initial external source will be set to give a steady initial steady state with the reactivity equal to RHOZRO.

471-490

EXSOTB (L)

Relative point and spatial kinetics external source values at times given in EXSOTM.

491-510

EXSOTM (L)

s

Times for point and spatial kinetics external source values given in EXSOTB. See also NEXSO and RHOZRO. The time dependence for the point kinetics external source specified by RHOZRO will be given by the pairs of values entered in EXSOTB and EXSOTM. For RHOZRO < 0 and NEXSO = 0, a constant external source will be used. The EXSOTB values will be normalized to unity at t = 0. The time dependence for the spatial kinetics external source specified on the FIXSRC FILE will be given by the pairs of values entered in EXSOTB and EXSOTM. For NEXSO = 0, a constant external source will be used. The EXSOTB values will be normalized to unity at t = 0.

511-630

DKBET2 (L,IPW)

Decay heat precursor yield for group L in decay heat curve IPW. 1 ≤ L ≤ NDKGRP ≤ 24 1 ≤ IPW ≤ NPOWDK ≤ 5 Decay heat data for curve IPW may be present in either BETADK/DKLAM or DKBET2/DKLAM2. If data is present in both locations, values in DKBET2/DKLAM2 will be used.

631-750

DKLAM2 (L,IPW)

1/s

Decay heat decay constant for DKBET2(L,IPW).

751-800

DKFRAC (IPR,IPW)

Fraction of user-supplied decay heat curve IPW to be used in decay heat region IPR. 1 ≤ IPR ≤ NDKREG ≤ 10 1 ≤ IPW ≤ NPOWDK ≤ 5 NDKREG is determined internally by the code based on the input of DKFRAC and DKANSI (below). A maximum of 10 regions can be defined. By default, DKFRAC is a NPOWDK by NPOWDK identity matrix, providing compatibility with old input files. (Regions and curves have the same meaning in this case).

801-880

DKANSI (IPR,N)

Fraction of built-in ANS standard decay curve N to be used in decay heat region IPR.

N = 1: U-235 thermal fission

N = 2: Pu-239 thermal fission

N = 3: U-238 fast fission

N = 4: Pu-241 thermal fission

5 ≤ N ≤ 8 is reserved for future standard curves.

881-920

PWLVL2 (K,IPR-5)

Table of normalized total power for initializing decay power in decay heat region IPR. 1 ≤ K ≤ NPDKST ≤ 8 6 ≤ IPR ≤ NDKREG ≤ 10 PWLVL2 is a continuation of table POWLVL.

921-960

PWTIM2 (K,IPR-5)

s

Duration of initializing power level PWLVL2(K,IPR-5). PWTIM2 is a continuation of table POWTIM.

961-968

QETOT (N)

MEV/fission

Total recoverable energy per fission for the fissionable isotope associated with built-in standard decay curve N. See DKANSI. Default is 200 MeV/fission.

N = 1: U-235 thermal fission

N = 2: Pu-239 thermal fission

N = 3: U-238 fast fission

N = 4: Pu-241 thermal fission

5 ≤ N ≤ 8 is reserved for future standard curves.

969-1000

DUMPNA

Not currently used.