Atomerımővi reaktor töltettervezése, főtıelem átrakás, reaktorfizikai korlátok, indítási mérések. Nemes Imre, Beliczai Botond PA Zrt

Átírás

1 Atomerımővi reaktor töltettervezése, főtıelem átrakás, reaktorfizikai korlátok, indítási mérések Nemes Imre, Beliczai Botond PA Zrt

2 Tartalom Üzemanyag cserérıl általában Reaktorfizikai korlátok Reaktorfizikai mérések és értékelésük Töltettervezés módszerei és eszközei Pakson

3 Üzemanyag csere általában Ciklikus mőködéső reaktorok : PWR,BWR ciklus (kampány) hosszát meghatározzák technológia feltételek, gazdaságossági megfontolások reaktivitás tartalék Reaktivitás tartalék : friss üzemanyag értékessége : dúsítás, uránsúly, geometria átlagos kiégés

4 Dúsítás-kiégés-kampányhossz

5 Tipikus VVER-440 töltet 9.0 Time= 0.00 eff.day Power= MW Tin.= C Mod.Flow= t/h Cb= g/kg Reactivity= % h6 pos.= 0 cm -Ass.pos. -AssAge.8 -AssBu[MWd/kgU] Results of C-PORCA Calculations Unit= Cycle= AssAge:.84: :.84.4:.6.:.4.0:..8:.0.6:.8.4:.6.:.4.0:..80:.0.60:.80.40:.60.9: :.9 code info://6/val/kov/0/-/- parameters: value: sec: ass.pos: pinpos: layer: Ass.Pow-max[MW]: Ass.Bu-max[MWd/kgU]: PinPow-max[kW]: PinBu-max[MWd/kgU]: Tsub-max[C]: Nlin-max[W/cm]: Nlin-limit[W/cm]: LocPinBu-max[MWd/kgU]:

6 Reaktorfizikai korlátok Neutron és hıfizikai paraméterek listája, amelyek a reaktor stacioner állapotát jellemzik Korlátként, keretként szolgálnak, betartásuk szükséges a reaktor biztonságos állapotához Tervezéskor olyan töltetet rakunk össze, hogy ezek a limitek teljesüljenek

7 The way of determination during SA Equilibrium cycle features used as a basis Key parameters of a given analysis were chosen Parameters adjusted to provide conservative results Conservatism include : Uncertainty of parameter Deviations in transient cycles Conservatism limited by acceptance criteria physical feature of model

8 SABL tables/ Local power and temperature limits Parameter Limitation Reactor state Maximal linear heat rate () < 5 W/cm all (burnup dependent) Maximal subchanel outlet temperature T sat all Burnup limits Parameter Assembly burnup Pin burnup Pin local (pellet) burnup Limitation < 49 GWd/tU < 55 GWd/tU < 64 GWd/tU

9 SABL tables/ Limits of control rod worth Parameter Limitation Reactor state Efficiency of all control rods, except the most effective one > 500 pcm all Integral efficiency of group 6 rods (regulating group ) > 00 pcm all < 500 pcm Efficiency of one ejected rod < 0 pcm < 70 pcm FP HZP Differential rod efficiency < 0.07 $/cm near critical Limits on reactivity conditions Parameter Limitation Reactor state Critical boric acid concentration < 0.5 g/kg all (HZP) Shutdown margin () <-000 pcm HZP ( 60 C) Shutdown margin () < 0 ZP, 0 C Minimal subcriticality during refuelling condition (the most effective follower in the core) < pcm Zero power, 00 C

10 SABL tables/ Reactivity feedback coefficient limits Parameter Limitation Reactor state Boric acid efficiency Moderator temperature efficiency Doppler efficiency < -900 pcmkg/g all > -000 pcmkg/g all < 0.0 pcm/k > pcm/k all < -.4 pcm/k all > -4.9 pcm/k

11 Uncertainty determination linear power, subchanel temperature burnup limits : a detailed analysis taking into account material tolerances and calculation errors boron concentration, boron worth, moderator temperature coefficient, control rod worth : deviations between the measured and calculated parameter values. Rest of parameters : benchmark calculations

12 Parameter uncertainties Parameter Maximal linear heat rate Maximal subchanel outlet temperature Uncertainty 9 W/cm 7.5 C Assembly burnup 7.65 % Pin burnup.6 % Pin local (pellet) burnup.6 % Efficiency of all control rods, except the most effective one 0 % Integral efficiency of group 6 rods (regulating group ) 0 % Efficiency of one ejected rod 0 % Differential rod efficiency $/cm Critical boric acid concentration 4.5 % Shutdown margin () 750 pcm Shutdown margin () 750 pcm Minimal subcriticality during refuelling condition (the most effective 750 pcm follower in the core) Boric acid efficiency 00 pcm/kg*g Moderator temperature efficiency.5 pcm/c Doppler efficiency 0 %

13 Startup test at NPP Paks What we measure? Why we measure these? How to evaluate results? How we declare the acceptance of results?

14 Purposes of measurements Long term : data collection for the testing of calculated parameter uncertainty Short term : immediate decision to declare the goodness of refuelled core checking of parameter value difference between measured and calculated value Both case purpose : check the most important parameters summarised in SABL table

15 Start-up test program of NPP Paks Test Criticality test Test of control rod driver connection Short description Criticality at 0-0 C Measur. of critical c b after stabilisation Reactivity changes during the movement of each CR ρ/ t measurement Heating of primary circuit 0-60 C Measurement of reactivity through quasistatic states Efficiency of central rod Measurement of effectivity of all rods except the most effective one Measurement of reactivity through quasistatic states Rod drop measurement ( dynamic) Thermocouple calibration ρ/ h 6, ρ/ c b measurement Symmetry measurement Check of power distribution In a stable state with homogeneous temperatures Dilution of primary circuit Measurement of reactivity through quasistatic states on power

16 Types of acceptance criteria Absolute : prescription for the measured value provide the parameter value within the limit Relative : prescription for the bias from calculated provide the accuracy of calculation within a range through the calculation and bias provide the parameter values within the limit

17 Measured parameters and acceptance criterias at NPP Paks practice Measured parameters Critical boron at HZP Acceptance criteria Absolute yes Relative yes ρ/ t m yes yes Effectivity of all rods except the most effective one efficiency of central rod no no yes yes ρ/ h 6, ρ( h 6 ) no yes

18 Töltettervezés módszerei és eszközei Pakson CERBER COBRA FGCS library ( BOSSY version ) HELIOS Burnup state files INPUT surface (BEA ) General INPUT C-PORCA 6.0 OUTPUT surface ( C-COW ) General Output FGCS library VERONA Cycle data Refuelling documentation

19 HELIOS application for Paks Generate few-group cross section libraries for C-PORCA.0, 5.0, nodal and pin-wise models Validate few-group diffusion codes calculating different test cases

20 HELIOS few-group cross section calculations / Paks specific features 45 (90) -group D transport code detailed and flexible geomery developed handling and services few-group parameters for non-multiplying regions as well - no boundary conditions Pin-cells with different spectral position handled separately

21 Geometries for HELIOS calculation

22 CERBER - for refuelling design Fast and effective D nodal diffusion model ( C-PORCA.0) Interactive WINDOWS surface - Bossy version Different options of automatic optimisation

23 The BOSSY WINDOWS surface for CERBER calculations

24 C-PORCA 6.0 -group D diffusion code - combined nodal and pin-wise calculations 0 axial layers, 7 cells/assembly Modules included for data preparations for VERONA system Detailed and continuous validation Developed services

25 Evaluation of C-PORCA results using C-COW output surface

26 C-PORCA 5.0 V&V mathematical benchmarks HELIOS tests : nodal and pinwise MCNP reference calculations NPP Paks measured data (more then 60 cycles) : global parameters, assembly power distribution Validation benchmarks : xenon, power distributions, non-measured parameters and cases