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

POW

1

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).

GENTIM

2

s

Prompt neutron lifetime.

POWTOT

3

W

Total reactor power.

BETADN (L)

4-9

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

DECCON (L)

10-15

1/s

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

OLDBDK (L)

16-21

Not currently used.

OLDDKL (L)

22-27

Not currently used.

OLDBDT

28

Not currently used.

PREATB (L)

29-48

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.

PREATM (L)

49-68

s

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

FRPR

69

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

FRFLOW

70

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

CRDLEN

71

m

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

CRDEXP

72

1/K

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

ACRDEX

73

$/m

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

BCRDEX

74

$/m^2

See ACRDEX.

CRDMC

75

J/K

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

CRDHA

76

W/K

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

UIVOL

77

m^3

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

RDEXPC

78

$/K

Coefficient in simple radial expansion feedback model.

XMCXAC

79

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.

SCRTAB

80-89

$

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

SCRTME

90-99

s

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

PRETB2 (K,IPW)

100-179

Normalized power table for power type IPW (K = 1-20, IPW = 2-5). Note: Table for type 1 is in PREATB.

PRETM2 (K,IPW)

180-259

s

Times for PRETB2 table.

BETADK (L,IPW)

260-289

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.

DKLAM (L,IPW)

290-319

1/s

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

BETAHT (IPW)

320-324

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.

POWLVL (K,IPR)

325-364

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.

POWTIM (K,IPR)

365-404

s

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

PUBYU

405

Not currently used.

HAUIS

406

W/K

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

XMCUI

407

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

SLLMAX

408

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.

PITCHG

409

m

Subassembly pitch at the grid at the reference temperature TR .

PITCHA

410

m

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

PITCHT

411

m

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

RDEXCF

412

$/m

Radial expansion coefficient for uniform core dilation.

TLPRRC

413

m

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

BNDMM1

414

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.

BNDMM2

415

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.

TINSRT

416

s

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

REAINS

417

$

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

TLIMIT

418

K

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

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

DFLTCS

419

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.

DFLTSS

420

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.

ACLPRC

421

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.

FCDTR1

422

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

FCDTR2

423

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

FCDTRF

424

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

DRCOLL

425

m

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

CRSAC

426

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.

RR1TC

427

s

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

RR2TC

428

s

Thermal response time constant for the top restraint ring.

ADDITIONAL INPUT FOR THE DETAILED CONTROL ROD EXPANSION MODEL

REQUIRED FOR ICREXP = 4.

RODID

429

m

Outside diameter of control rod driveline.

RODOD

430

m

Outside diameter of control rod driveline.

SHRDLN (K)

431-433

m

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

SHRDID (K)

434-436

m

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

SHRDOD (K)

437-439

m

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

RHOCRD

440

kg/m^3

Density of control rod structure.

HTCPCR

441

J/kg-K

Heat capacity of control rod structure.

CONDCR

442

W/m-K

Thermal conductivity of control rod structure.

VFCRD

443

Structure volume fraction in driveline core, remainder is sodium.

HFILM

444

W/m^2-K

Film coefficient on outer control rod shroud surface.

FLSHRD

445

kg/s

Flowrate in shroud annulus.

AREACR

446

m^2

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

FLOEXP

447

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

ADDITIONAL INPUT FOR THE DETAILED RADIAL CORE EXPANSION MODEL

REQUIRED FOR |IRADEX| > 3.

ACLPEL

448

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.

TLPEL

449

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.

PTCHRA

450

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.

PTCHRT

451

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.

RCBARR

452

m

Core barrel radius at the reference temperature TR.

FCDTCB

453

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

CB2TC

454

s

Thermal response time constant for the core barrel.

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

YKNF

455

∆k/(∆n/n)

Fuel number-density coefficient of reactivity.

YKHF

456

∆k/(∆h/h)

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

YKNNA

457

∆k/(∆n/n)

Sodium number-density coefficient of reactivity.

YKNSS

458

∆k/(∆n/n)

Steel number-density coefficient of reactivity.

YRCUR

459

∆k/K

Upper-reflector coefficient of reactivity.

YLCLR

460

∆k/K

Lower-reflector coefficient of reactivity.

YRCRR

461

∆k/K

Radial-reflector coefficient of reactivity.

YRCCR

462

∆k/K

Control-rod-flow coefficient of reactivity.

YRCGP

463

∆k/K

Grid-plate coefficient of reactivity.

YRCDOP

464

∆k

Non-linear Doppler-effect of reactivity.

YDELT0

465

K

Nominal core delta T at full reactor power.

YABOW

466

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

YBBOW

467

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

FCR

468

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

YTCUT

469

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

RHOZRO

470

$

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.

EXSOTB (L)

471-490

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

EXSOTM (L)

491-510

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.

DKBET2 (L,IPW)

511-630

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.

DKLAM2 (L,IPW)

631-750

1/s

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

DKFRAC (IPR,IPW)

751-800

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).

DKANSI (IPR,N)

801-880

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.

PWLVL2 (K,IPR-5)

881-920

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.

PWTIM2 (K,IPR-5)

921-960

s

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

QETOT (N)

961-968

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.

DUMPNA

969-1000

Not currently used.