efit-pb transient analysis m. schikorr, e. bubelis eurotrans: dm1 wp1.5 : “safety”

Forschungszentrum KarlsruheTechnik und Umwelt

IRS /FzK W.M.SchikorrEUROTRANS WP1.5 Safety Meeting : Karlsruhe, Nov 27-28, 2008 1

EFIT-Pb Transient AnalysisEFIT-Pb Transient Analysis

M. Schikorr, E. BubelisM. Schikorr, E. Bubelis

EUROTRANS: DM1 WP1.5 : “Safety”

Karlsruhe , 27-28 November 2008



1. Reactivity Coefficients for EFIT-Pb

2. SIM-ADS Transient Results for EFIT-Pb

3. Status D1.43 Deliverable : Transient Analysis of EFIT-Pb

Topics:



EFIT-Pb Reactivity Coefficient Calculations:Basic Data Source : G.Glinatsis, „EFIT-MgO/Pb Core Design Reactivity Coefficients” Genova, April Meeting 2008, and D-1.36

3.) Coolant density Effect: 1% dens

whole Active Core zones: (DK/K )/ 1% dens = 0.00058 0.00002

2.) Fuel Temperature Effect:

BoL: Keff = 0.96123 0.00027 (0.96147 0.00025);

BoC: Keff = 0.96183 0.00025 (0.96207 0.00025)

EoC: Keff = 0.96227 0.00026; (0.96227 0.00026).

4.) (ΔKeff/Keff) due to all „Thermal Expansions“:

from 400°C to HFP = − 0.00549 ± 0.00034.

T nom_fuel =1800 K

HFP Conditions:

T_fuel = 910 °C,

T_cool = 440 °C

1.) 400 °C Isothermal Conditions: K_eff_ref = 0.96654 +/- 0.00019



Calculated k_eff for different EFIT-Pb core states using MCNPX :

Basic Data Source : D1.36 (Glinatsis data)

Ref_state Isothermal

HFP T_fuel=1527°CCore region

Voided

T_cool_in [°C] 400 400 400 400

T_cool [°C] 400 440 440 voided

T_fuel [°C] 400 910 1527 910

BOL 0.96654 0.96123 0.96147 1.02740

BOC 0.96183 0.96207 1.02595

EOC 0.96227 0.96227 1.02373

K_eff for EFIT-Pb as calculated by MCNPX

Note : For the Safety Calculations the value of k_eff = 0.97403 at HFP and BOC is adopted. Value taken from Table 5.3, Ref [D-1.36]



Reactivities changes [pcm] for different EFIT-Pb core states using previous k_eff data from Glinatsis:

from 400°C (Ref_state) to

HFP

from HFP to T_fuel = 1527 °C

state

from HFP to Voided state

Axial Expansion Effect

[pcm] [pcm][pcm /1%density

change][pcm]

BOL -571.5 26.0 -67.0 -636.7

BOC -506.6 25.9 -64.7 -570.5

EOC -459.1 0.0 -62.4 -487.3



Calculated EFIT-Pb Reactivity Temperature Coefficients using prevoius Glinatsis k_eff data :

Fuel Temperature

Coeff: A_dopp [pcm]

Coolant Temperature

Coeff: [pcm/°C]

Axial Fuel Thermal

Expansion Coeff: [pcm/°C]

Diagrid expansion Coeff:

[pcm/°C] *

BOL 61.9 0.76 -1.25 -1.50

BOC 61.4 0.73 -1.12 -1.50

EOC 0.0 0.71 -0.96 -1.50

* assumed

2.) To calculate Coolant temperature reactivity coefficient need Pb coolant density.

Used : density lead = 11042 – 1.194*T_cool [°C] [kg/m^3]

1.) Diagrid expansion coefficient could not be extracted from the Glinatsis data as coolant inlet temperature remained at 400 °C for all different k_eff calculations. Thus assumed radial expansion coefficient = - 1.5 [pcm/°C], similiar to what is being observed in SPX1.



T_coolin T_cool T_fuel°C 400 440 910

HFP: BOL BOC EOCCoolant (pcm) 0.0 0.0 0.0Fuel Doppler (pcm) 0.0 0.0 0.0Fuel Expansion (pcm) 0.0 0.0 0.0Grid_Expansion 0.0 0.0 0.0Total [pcm] 0.0 0.0 0.0k_eff HFP 0.96123 0.97403 0.96227k_eff @ Temp_Iso 0.96123 0.97403 0.96227Margin to Criticality [$] -18.02 -24.1beta [pcm] 148 163Margin to Criticality [pcm] -2666 -3921


HFP to CZP : BOL BOC EOCCoolant (pcm) -45.4 -43.9 -42.3Fuel Doppler (pcm) -36.8 -36.5 0.0Fuel Expansion (pcm) 661.7 592.9 506.4Grid_Expansion 30.0 30.0 30.0Total [pcm] 609.5 542.5 494.1k_eff HFP 0.96123 0.97403 0.96227k_eff @ Temp_Iso 0.96689 0.97920 0.96687Margin to Criticality [$] -14.35 -21.0beta [pcm] 148 163Margin to Criticality [pcm] -2124 -3427


HFP to Ambient: BOL BOC EOCCoolant (pcm) -310.5 -299.9 -289.1Fuel Doppler (pcm) -84.3 -83.7 0.0Fuel Expansion (pcm) 1098.7 984.5 840.8Grid_Expansion 555.0 555.0 555.0Total [pcm] 1258.9 1155.9 1106.7k_eff HFP 0.96123 0.97403 0.96227k_eff @ Temp_Iso 0.97300 0.98512 0.97263Margin to Criticality [$] -10.20 -17.3beta [pcm] 148 163Margin to Criticality [pcm] -1510 -2814

Reactivity Balance going

1.) from HFP to CZP (T=380°C), and

2.) from HFP to Ambient (T= 30°C)

for EFIT-Pb for various Core states (BOL, BOC; EOC) using the various EFIT-Pb reactivity coefficients from previous slide



1. EFIT Pressure Drops: as proposed by Ansaldo after SA redesign leading to lower SA inlet and outlet pressure drops.

Ansaldo calculated pressure drops [14], mbar

Corresponding pressure drop coefficients (based on

coolant flowrate of 185 kg/s per SA)

SA Inlet 289 5.50 SA Outlet 86 1.64 Flow along smooth pin section

165

Grid spacers (6) * 94.4 Total core pressure drop 634.4 Total core pressure drop taking into account ~10 % uncertainty

700

Main HX (SG) [15] 400 7.61 Main pump [15] 270 5.16 Total pressure drop of the whole primary system

1370


IRS /FzK W.M.Schikorr EUROTRANS WP1.5 Safety Meeting : Karlsruhe, Nov 27-28, 2008

9

The EFIT Reactor Design:

4

EFIT is a pool-type reactor of about 400 MW power

Sub-critical reactor (Keff = 0.97) sustained by a spallation neutron source (beam proton energy 800 MeV and beam current 20 mA)

Reactor core with 3 U-free fuel zone with (Pu,MA)O2 in MgO matrix to improve the burning efficiency

Pure melt lead as primary coolant (lower cost and less activation products such as Polonium than LBE)

Core power is removed by forced circulation (4 pumps placed in the hot collector) through 8 steam generators with helical-coil tube bundle

4 DHR heat exchangers are immersed in the annular cold pool between the inner vessel and the reactor vessel

DHR

Steam generator

DHR

Steam generator

Pump

Core

Target

Reactor vessel

Inner vessel

heat exchanger

EFIT Reactor Block

Proton Beam

Figure Source: G. Bandini, P. Meloni, M. Polidori (ENEA - Bologna)



SIMMER-III ANSALDOResults at after 1 hourt = 3600 s: (P = 16 MW)

mC = 2740 kg/s

mD = 2983 kg/s 2985 Kg/s

TCi = 410.5 C

TCo = 449.1 C

TDi = 444.6 C 444 C

TDo = 407.0 C 407 C

y = mC(TDi - TDo)

(TCi - TDo)

x = y + mD - mC

y = 255 kg/s

Recirculation ratio at DHR outlet:x = 498 kg/s (17% of mD)

Simplified scheme of RELAP5 model

xy

mC

mD

TCi

TCo

TDo

TDi

TDi

TCi

TCo

TCi

TCo


mC = 2740 kg/s

mD = 2983 kg/s 2985 Kg/s

TCi = 410.5 C

TCo = 449.1 C

TDi = 444.6 C 444 C

TDo = 407.0 C 407 C

y = mC(TDi - TDo)

(TCi - TDo)

x = y + mD - mC

y = 255 kg/s



xy

mC

mD

TCi

TCo

TDo

TDi

TDi

TCi

TCo

TCi

TCo

xy

mC

mD

TCi

TCo

TDo

TDi

TDi

TCi

TCo

TCi

TCo


The In-vessel Flow Paths during normal Heat Removal mode:


IRS /FzK W.M.Schikorr EUROTRANS WP1.5 Safety Meeting : Karlsruhe, Nov 27-28, 2008

11

The Decay Heat Removal (DHR) System of EFIT-Pb

The DHR system is conceived for inherently safe decay heat removal and passive mode actuation

4 independent loops partially filled with organic oil, that dissipate the decay heat to the atmosphere by natural convection circulation

Each loop consists of a dip cooler immersed in the cold pool where the oil partially vaporize and an air-vapor condenser with stack chimney and interconnecting piping

Oil boiling point is determined by superimposed pressure of an inert gas

In normal operation the oil is below its boiling point and the DHR removes only heat losses from SGs and inner vessel (few 100 kW) to keep cold the upper part of the reactor vessel

Condensed Oil

Boiling Oil

Cooling air Chimney

Air Vapour Condenser

Nitrogen Header

Oil VapourSeparator

Condensed Oil Drum

EFIT ReactorSafety-Related DHR Loop

DHRDip Cooler

Inner vessel

Reactor vessel





mC = 2740 kg/s

mD = 2983 kg/s 2985 Kg/s

TCi = 410.5 C

TCo = 449.1 C

TDi = 444.6 C 444 C

TDo = 407.0 C 407 C

y = mC(TDi - TDo)

(TCi - TDo)

x = y + mD - mC

y = 255 kg/s



xy

mC

mD

TCi

TCo

TDo

TDi

TDi

TCi

TCo

TCi

TCo


mC = 2740 kg/s

mD = 2983 kg/s 2985 Kg/s

TCi = 410.5 C

TCo = 449.1 C

TDi = 444.6 C 444 C

TDo = 407.0 C 407 C

y = mC(TDi - TDo)

(TCi - TDo)

x = y + mD - mC

y = 255 kg/s



xy

mC

mD

TCi

TCo

TDo

TDi

TDi

TCi

TCo

TCi

TCo

xy

mC

mD

TCi

TCo

TDo

TDi

TDi

TCi

TCo

TCi

TCo


The In-vessel Flow Paths during the Decay Heat Removal mode:



EFIT-Pb Transient Cases Analysed using SIM-ADS



Conclusions: Status of Deliverable D1.43 How to continue and finalize our EFIT-PB transient anlysis:

1. Some sections are already finished.

2. Each of us needs to write a short text for each transient describing briefly what you did and what you found. Not more than about 1 page per transient by middle of December (15. 12.2008).

3. I will supply to you for each transient the typical frame of the chapter. In your section of that chapter, please insert your text. If you want, you can also insert your figures and tables in the provided format. Important: retain format otherwise we will have chaos in formatting final report.

4. Evaldas and I will collate the various contributions into final chapters for each transient.

5. Evaldas and myself will then finally collate the entire report for your inspection middle of January 2009 .

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