First experiences with Gd fuel assemblies in the Paks NPP Tams Parkó, Botond Beliczai AER Symposium 2009.09.21 25.
Introduction From 2006 we increased the heat power of our units by 8% For reaching this goal we used fuel assemblies with higher pin pitch (12,3 mm instead of 12,2 mm) in order not to violate the limits prescribed for maximal subchannel outlet temperature and pin power Because of the increase of the heat power we had to use 102 fresh FAs instead of 90 fresh FAs It can be seen that the relative fuel cost increased We made a decision to introduce higher enriched FAs in order to decrease the relative fuel cost Based on many calculations and taking into account many different factors we decided to apply the following Gd fuel assemblies The TVEL company fabricated this assembly for us
GD 2N fuel assembly
Properties of the new fuel assemblies Diameter of fuel pin - Height of fuel pin in the working FA Height of fuel pin in the working control FA - Outer diameter of fuel pellet - Inner diameter of fuel pellet - Lattice pitch of fuel pins - Thickness of the shroud of working and control FAs - Outer diameter of working and control FAs - - 9,1 mm; - 2480 mm; - 2360 mm; - 7,6 mm; - 1,20 mm; - 12,3 mm; - 1,5 mm; - 145 mm;
Features of the equlibrium cycle/1 FUEL DESCRIPTION 1ST C. 2ND C. 3RD C. 4TH C. 5TH C. 3-gd plcs munka k. 72 12.06 78 25.35 72 37.19 78 45.16 12 47.27 3-gd plcs.hf fol. 12 15.65 6 28.37 12 41.27 6 47.68 0 0.00 1.6%-os follower 0 0.00 1 18.91 0 0.00 0 0.00 0 0.00
Features of the equlibrium cycle/2 teff power rodh6 tin flow cb apmax s po ppmax s po pin tsmax s po cha nlmax nllim nltar s po le pin 0.0 1485.0 212.0 267.0 30000.0 6.13 5.56 1 13 47.5 1 13 92 316.4 1 13 176 236.7 325.0 88.3 1 9 10 35 5.0 1485.0 212.0 267.0 30000.0 6.13 5.64 1 13 48.0 1 13 92 316.9 1 13 176 235.5 325.0 89.5 1 24 10 122 20.0 1485.0 212.0 267.0 30000.0 5.71 5.63 1 13 47.9 1 13 92 316.8 1 13 176 232.2 325.0 92.8 1 24 10 122 40.0 1485.0 212.0 267.0 30000.0 5.28 5.54 1 13 47.2 1 13 92 316.1 1 13 176 230.3 325.0 94.7 1 9 9 35 60.0 1485.0 212.0 267.0 30000.0 4.86 5.47 1 24 47.1 1 24 124 316.0 1 24 245 229.2 325.0 95.8 1 9 9 35 80.0 1485.0 212.0 267.0 30000.0 4.44 5.49 1 24 47.1 1 24 124 315.9 1 24 245 228.0 325.0 97.0 1 9 8 35 100.0 1485.0 212.0 267.0 30000.0 4.03 5.50 1 24 47.0 1 24 111 315.9 1 24 245 161.0 258.8 97.7 1 15 12 71 120.0 1485.0 212.0 267.0 30000.0 3.63 5.50 1 24 47.0 1 24 111 315.9 1 24 216 158.8 256.5 97.7 1 15 12 71 140.0 1485.0 212.0 267.0 30000.0 3.22 5.51 1 24 47.0 1 24 111 315.9 1 24 216 156.9 254.3 97.4 1 15 12 71 160.0 1485.0 212.0 267.0 30000.0 2.82 5.51 1 24 46.9 1 24 111 315.8 1 24 216 155.2 252.1 96.9 1 15 7 71 180.0 1485.0 212.0 267.0 30000.0 2.42 5.52 1 24 46.8 1 24 111 315.7 1 24 216 155.3 250.8 95.4 1 44 7 23 200.0 1485.0 212.0 267.0 30000.0 2.02 5.51 1 24 46.8 1 24 111 315.7 1 24 216 155.0 248.6 93.6 1 44 6 23 220.0 1485.0 212.0 267.0 30000.0 1.62 5.51 1 24 46.7 1 9 35 315.6 1 24 216 154.6 246.3 91.8 1 44 6 23 240.0 1485.0 212.0 267.0 30000.0 1.22 5.50 1 24 46.6 1 54 82 315.5 1 24 216 153.5 243.5 90.0 1 44 5 13 260.0 1485.0 212.0 267.0 30000.0 0.82 5.50 1 24 46.4 1 9 35 315.4 1 24 216 153.2 241.3 88.1 1 44 5 13 280.0 1485.0 212.0 267.0 30000.0 0.42 5.49 1 24 46.3 1 9 35 315.3 1 24 216 152.9 239.1 86.2 1 44 5 13 300.0 1485.0 212.0 267.0 30000.0 0.03 5.48 1 24 46.1 1 24 111 315.2 1 24 216 152.5 236.9 84.4 1 44 5 13 320.0 1485.0 225.0 267.0 30000.0-0.31 5.48 1 24 46.0 1 24 111 315.1 1 24 216 153.7 234.6 80.9 1 15 16 71 323.0 1485.0 245.0 267.0 30000.0-0.26 5.48 1 24 46.1 1 9 35 315.2 1 24 245 162.2 234.3 72.0 1 15 17 71 325.0 1485.0 245.0 267.0 30000.0-0.30 5.48 1 24 46.1 1 9 35 315.2 1 24 245 162.5 234.1 71.5 1 15 17 71
Schedule of applying the new assemblies in the Paks NPP 2009: 18 test FAsarrivedinthePaks NPP 2010: new FAs for the whole core 12 test FAs (working) were put into the 4th unit 6 test FAs (control) will be put into the 3rd unit The 4th unit was restarted in June The 3rd unit will be restarted next month we have preliminary results about the differences between measurements and calculations (and only for working FAs)
Comparison of calculated and measured thermocouple signals of Gd fuel assembly /1. 2.0 Szmított - mért kilépő hőmérséklet C-PORCA; 34. szimmetriacsoport 1.5 1.0 ] [C s ré lté e 0.5 0.0-0.5-1.0-1.5-2.0 kiégés [effektí nap]
Comparison of calculated and measured thermocouple signals of Gd fuel assembly /2. 2.0 Szmított - mért kilépő hőmérséklet C-PORCA; 57. szimmetriacsoport 1.5 1.0 0.5 ] [C s ré 0.0 lté e -0.5-1.0-1.5-2.0 kiégés [effektív nap]
Distribution of calculated and measured thermocouple signals for all assemblies and for Gd fuel assembly 6000 Szmoltés mért Tk hőmérséklet eltérések gyakorisg eloszlsa külön külön az összes és a Gd 2n kazettatípusra C PORCA eredmények 5000 4000 összes típus tlag= 0.09[C] szórs=0.64 [C] 3000 2000 1000 összes Gd 2n tlag= 0.88[C] szórs=0.63 [C] 0 2.88 2.63 2.38 2.13 1.88 1.63 1.38 1.13 0.88 0.63 0.38 0.13 0.13 0.38 0.63 0.88 1.13 1.38 1.63 1.88 2.13 2.38 2.63 2.88 szmított mért dt gyakorisg eloszls az összes kazettatípusra szmított mért dt gyakorisg eloszls szorozva tízzel a 34 es szimmetria pozícióban szmított mért dt gyakorisg eloszls szorozva tízzel a 57 es szimmetria pozícióban
Comparison of calculated and measured DPZ currents of Gd fuel assembly /1. 0.0% Szmolt és mért DPZ ramok relatív eltéréseinek tlaga lnconként a 34. szimmetriapozícióban ] [% -0.5% a g tla ti n k é n c o n -1.0% l m ra Z P D lt o -1.5% z m rt)/s é lt-m o z m (s -2.0% -2.5% Kiégés [effektív nap]
Comparison of calculated and measured DPZ currents of Gd fuel assembly /2. 0.0% Szmolt és mért DPZ ramok relatív eltéréseinek tlaga lnconként a 57. szimmetriapozícióban ] [% -0.5% a g tla ti n k é n o c n -1.0% l m ra Z P D lt o m-1.5% z rt)/s é lt-m o m z -2.0% (s -2.5% Kiégés [effektív nap]
Distribution of calculated and measured DPZ currents for all assemblies and for Gd fuel assembly 8000 Szmoltés mért DPZ ramok relatív eltéréseinek gyakorisg eloszlsa külön külön az összes és a Gd 2n kazettatípusra C PORCA eredmények 7000 6000 5000 4000 3000 2000 1000 0 11.5% 10.5% 9.5% 8.5% 7.5% 6.5% 5.5% 4.5% 3.5% 2.5% 1.5% 0.5% 0.5% 1.5% 2.5% 3.5% 4.5% 5.5% 6.5% 7.5% 8.5% 9.5% 10.5% 11.5% relatív eltérések gyakorisga az összes kazettatípusra relatív eltérések gyakorisga szorozva tízzel a 57 es szimmetriacsoportban relatív eltérések gyakorisga szorozva tízzel a 34 es szimmetriacsoportban
Summary Very short time went by, very few assemblies Correct conclusions can not be made yet However, it seems that our thermalhydraulical modell is capable of determining the thermocouple signals in case of Gd-fuel assemblies Part of the difference between measured and calculated values can be explained from reactorphysical point of view and the rest can be explained from thermalhydraulical point of view