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1Second International Symposium on Nuclear Power Plant Life Management15-18 October 2007, Shanghai, China
NEUTRON ACTIVATION OF REACTOR COMPONENTS DURING OPERATION LIFETIME OF A NPP
Gunter Pretzsch, Bernhard Gmal, Ulrich Hesse and Klemens Hummelsheim
Gesellschaft für Anlagen- und Reaktorsicherheit (GRS) mbHKurfürstendamm 200, 10719 Berlin, Germany
prg@grs.de
2Second International Symposium on Nuclear Power Plant Life Management15-18 October 2007, Shanghai, China
Content
� Introduction
� GRS code systems for activation analysis
� Validation against experimental data
� Comparison of a standard and an extended calculation method
� Example for application: PWR 40 years operation time
3Second International Symposium on Nuclear Power Plant Life Management15-18 October 2007, Shanghai, China
Introduction� Knowledge of the activation level of neutron irradiated materials during lifetime
of a NPP important for decommissioning� Evaluation of new decommission technologies with respect to radiation
protection and waste management� Besides measurements theoretical activation calculations provide important information, e.g. for work planning� Determination of inventories for management and disposal of the activated materials
4Second International Symposium on Nuclear Power Plant Life Management15-18 October 2007, Shanghai, China
GRS code systems for activation analysis
� Own-developed systems with the updated ORNL code ORIGEN as main tool� Standard system GRSAKTIV is based on ENDF/B-V data for three neutron
energy groups up to 10 MeV for six neutron reaction channels � Extended activation code GRS-ORIGENX is based on point data files ENDF/B-VI / JEF2.2 / JENDL3.2 / European Activation File 97, here
condensed to six groups up to 20 MeV for 15 channels� Application will be shown with respect to decommissioning of NPP� Extended neutron reaction channels and program flow chart in the next files
5Second International Symposium on Nuclear Power Plant Life Management15-18 October 2007, Shanghai, China
Development of advanced methods and libraries for activation calculations
Standard
Extended
6Second International Symposium on Nuclear Power Plant Life Management15-18 October 2007, Shanghai, China
1d ANITABLE
2d R-Z DORT
ABBRAND1d Burn-up calculation
ABSCHIRMUNGIsotopic XS, n-γ source terms,
2d radiation transport calculation, 2d dose
calculation, 2d neutron spectra calculation
AKTIVIERUNGActivation
calculations for multiple material
regions
1d OREST
DORTABLE GRSAKTIV
GRS-ORIGENX
Program Flow Chart of the burn-up, shielding and activation AAA-Sequence
7Second International Symposium on Nuclear Power Plant Life Management15-18 October 2007, Shanghai, China
Validation of the AAA-Sequence Activation Method� Calculation of 3 cycle irradiation of assembly structure materials in a full core
RZ DORT simulation and C/E comparison with experimental data (upper part, singular head screw) of a German NPP
� Calculation of 1 hour irradiation of a concrete sample of biological shield in a highly thermalized neutron flux and C/E comparison with experimental data of a Japanese research reactor
� C/E = Calculated / Experimental� Both methods GRSAKTIV and ORIGENX show satisfying results. Most
deviations are similar to other publications. But �� New ORIGENX inelastic scatter reaction (n,n1) for 93m Niobium can now be
compared to experiment � new:
8Second International Symposium on Nuclear Power Plant Life Management15-18 October 2007, Shanghai, China
Comparison of activation results GRSAKTIV and GRS-ORIGENX at a single head screw of assembly BE318 of NPP BIBLIS at discharge after 3 fuel cycles irradiation
00,10,20,30,40,50,60,70,80,91
1,11,21,31,41,51,61,71,8
71 d 5,3 a 312 d 84 d 2,7 a 45 d 28 d 8E4 a 100 a 2E4 a 16 a58Co 60Co 54Mn 46Sc 55Fe 59Fe 51Cr 59Ni 63Ni 94Nb 93mNb
Analyzed radioactive Isotopes in Steel <1.4541> and their Halflifes
Calcu
lated
/Expe
rimen
t
C/E GRSAKTIV
C/E ORIGENXnew:
9Second International Symposium on Nuclear Power Plant Life Management15-18 October 2007, Shanghai, China
Comparison of activation results GRSAKTIV and GRS-ORIGENX in concrete after 1 hour irradiation of JAERI JRR-4 research reactor
0,000,100,200,300,400,500,600,700,800,901,001,101,201,301,401,501,601,701,80
46Sc 51Cr 54Mn 59Fe 60Co 65Zn 124Sb 134Cs 141Ce 152Eu 177Lu 181Hf 182Ta 233PaAnalyzed radioactive Isotopes in Concrete
Calcu
lated
/Expe
rimen
t
C/E GRSAKTIV
C/E ORIGENX
10Second International Symposium on Nuclear Power Plant Life Management15-18 October 2007, Shanghai, China
Applications with regard to the operation lifetime of a real NPP� A: Core inventory and flux strength in the active region calculated by OREST� AA: Reactor simulation with assembly structures, core basket, reactor vessel
and biological shield and coolant with axially different density and temperature with DORT-DORTABLE in 83 groups, anisotropic order PL=3, 32 neutron energy groups for thermal up-scatter
� Automatically neutron spectra and attenuation factors are calculated in 187 material regions and more than 10,000 mesh points for activation calculations
� AAA: GRSAKTIV and ORIGENX activation calculations based on the operation lifetime 40 years of a real PWR with 3000 MW thermal energy output
� Next figure shows normalized flux distributions of DORT at core, vessel and biological shield (other regions omitted)
11Second International Symposium on Nuclear Power Plant Life Management15-18 October 2007, Shanghai, China
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
corecore basket
RV2RV5
Bio1Bio4
1,00E-08
1,00E-07
1,00E-06
1,00E-05
1,00E-04
1,00E-03
1,00E-02
1,00E-01
1,00E+00
1,00E+01
Norm
alize
d Neu
tron F
lux St
reng
th
Axial Layers
Radial Layers
coresurroundwater1core basketwater2RV1RV2RV3RV4RV5airisolationBio1Bio2Bio3Bio4Bio5
Lower and upper part of Core
Vessel
Concrete
12Second International Symposium on Nuclear Power Plant Life Management15-18 October 2007, Shanghai, China
Activation results of reactor vessel in the short time range one month after shut down and 40 years operation lifetime� Calculations of flux distributions of 83 groups DORTABLE repeated and proved
with three other deep penetration cross section libraries up to 175 groups (EURLIB-99)
� Neutron fluxes vary strongly inside of vessel material � five material layers RV1-RV5 of steel <22NiMoCr37> had to be activated separately and averaged
� Next table for reactor vessel steel shows excerpt of assumed trace elements <22NiMoCr37> and most important radioactive isotopes calculated with STAndard and EXTended Method GRSAKTIV (=ENDF/B-V) and ORIGENX (=ENDF/B-VI + others) in 83 energy groups
� Differences between STA and EXT not so great. Problems Co-58 and Mo-99!� New Isotope Fe-60 detected in calculation, but very low activities!
13Second International Symposium on Nuclear Power Plant Life Management15-18 October 2007, Shanghai, China
+41.16E+061.12E+06Total Activity�-64.49E+024.24E+02152Eu0.1 63-Eu-32.75E+012.66E+01134Cs0.1 55-Cs
+ 44 �7.49E+001.08E+0199Mo+ 201.40E+011.68E+0193Mo7,00042-Mo+156.88E+037.88E+0363Ni+86.42E+016.91E+0159Ni
+ 86 �4.31E+038.05E+0358Co9,00028-Ni+0.28.25E+048.27E+0460Co30027-Co
� New reaction5.52E-080.060Fe+ 271.90E+042.43E+0459Fe-59.67E+059.21E+0555Feremainder26-Fe-156.11E+045.22E+0454Mn10,00025-Mn / 26-Fe+161.41E+041.64E+0451Cr5,00024-Cr-81.99E+021.84E+0232P20015-P+41.37E+021.42E+0214C2,100 / 590 06-C / 07-N -13.25E+033.22E+033H1.0 03-Li
Difference %(STA-EXT)/EXT
GRS-ORIGENX EXTended (Bq/g)
GRSAKTIV STAndard (Bq/g)
Nuclideactivated
Content (ppm)TraceElements
14Second International Symposium on Nuclear Power Plant Life Management15-18 October 2007, Shanghai, China
Activation of the NPP biological shield in the short time range one month after shut down and 40 years operation lifetime
� Neutron fluxes vary very strongly inside of biological shield � five material layers BIO1-BIO5 of 92 % concrete with 8 % construction steel had to be separately activated and averaged
� Neutron spectra are very thermalized in contrast to the reactor vessel� Next table for the biological shield shows excerpt of trace elements and most
important radioactive isotopes calculated with STAndard and EXTendedMethod GRSAKTIV (=ENDF/B-V) and ORIGENX (=ENDF/B-VI + others)
� Differences between STA and EXT not so great. Problems Ar-37 and Co-58 !
15Second International Symposium on Nuclear Power Plant Life Management15-18 October 2007, Shanghai, China
-151.84E+41.56E+04Total Activity�-231.10E+018.53E+00154Eu07.78E+017.77E+01152Eu0.1363-Eu-282.54E+011.82E+01134Cs0.6155-Cs-93.62E+003.30E+0065Zn10.6930-Zn+ 27.15E+017.26E+0163Ni
+ 50 �5.05E+007.55E+0058Co9,00028-Ni-101.04E+039.43E+0260Co3002.3727-Co02.27E+022.27E+0259Fe-161.13E+049.47E+0355Feremainder10,50026-Fe-328.07E+015.52E+0154Mn10,00025-Mn-21.48E+021.45E+0251Cr50009.0724-Cr-36.95E+016.76E+0146Sc0.1 2.8121-Sc-14.05E+033.99E+0345Ca-32.24E+012.17E+0141Ca
-62 �1.29E+034.86E+0237Ar195,00020-Ca-33.39E+013.29E+013H1.0 03-Li
Difference %(STA-EXT)/EXT
GRS-ORIGENXEXTended (Bq/g)
GRSAKTIVSTAndard (Bq/g)
Nuclideactivated
8 %Steel (ppm)
92 %Concrete (ppm)
TraceElements
16Second International Symposium on Nuclear Power Plant Life Management15-18 October 2007, Shanghai, China
Analyses of important radioactive isotopes in the intermediate time range up to 100 years after shutdown of NPP
� Next figures show activities of most important isotopes in the reactor vessel and the biological shield in units (Bq/g)
� These calculations done by using the GRSAKTIV system� In the vessel the activities after one year cooling time are dominated by Fe-55,
Co-60, Ni-59 and Ni-63� In the biological shield plus construction steel the activities after one year
cooling time are dominated by C-14, Fe-55, Co-60, Ni-63 and Eu-152
17Second International Symposium on Nuclear Power Plant Life Management15-18 October 2007, Shanghai, China
Activities reactor vessel after 40 years operation time in units Bq/g
1,00E-051,00E-041,00E-031,00E-021,00E-011,00E+001,00E+011,00E+021,00E+031,00E+041,00E+051,00E+061,00E+07
0 10 20 30 40 50 60 70 80 90 100decay time
spec
ific ac
tivity
Bq/g
H 3C 14CR 51MN 54FE 55FE 59CO 58CO 60NI 59NI 63NB 93MNB 94MO 93CS134EU152totals
totals
18Second International Symposium on Nuclear Power Plant Life Management15-18 October 2007, Shanghai, China
Activities reactor biological shield after 40 years operation time in units Bq/g
1,00E-05
1,00E-04
1,00E-03
1,00E-02
1,00E-01
1,00E+00
1,00E+01
1,00E+02
1,00E+03
1,00E+04
1,00E+05
0 10 20 30 40 50 60 70 80 90 100decay time
spec
ific ac
tivity
Bq/g
H 3C 14CR 51MN 54FE 55FE 59CO 58CO 60NI 59NI 63NB 93MNB 94MO 99CS134EU152totals
19Second International Symposium on Nuclear Power Plant Life Management15-18 October 2007, Shanghai, China
Analyses of important Gamma emitting isotopes in the intermediate time range up to 100 years after shutdown of NPP� Many radioactive isotopes are weak gamma emitters (H-3, Fe-55), but gamma
emission is important for dose rates and radiation protection� Next figures shows Gamma power (W/g) of important isotopes in reactor vessel
and biological shield � The calculations are done by using GRS-ORIGENX� In the vessel the activities after one year cooling time are mostly dominated by
Co-60 and at 100 years cooling time additionally Eu152 and Ni-59� In the biological shield plus construction steel the activities after one year are
dominated by Co-60 and Eu-152� Cobalt contents in structure steel materials vary from ~100 up to ~ 3000 ppm!� Europium trace concentrations very low ~ 0.1 ppm and not always well known!
20Second International Symposium on Nuclear Power Plant Life Management15-18 October 2007, Shanghai, China
ORIGENX: Reactor Vessel Gamma Power (W/g) after 40 years operation time
1,00E-15
1,00E-14
1,00E-13
1,00E-12
1,00E-11
1,00E-10
1,00E-09
1,00E-08
1,00E-07
1,00E-06
0 10 20 30 40 50 60 70 80 90 100decay time
spec
ific G
amma
Powe
r W/g
MN 54
FE 59
CO 58
CO 60
NI 59
NB 93M
MO 93
EU152
EU154
EU155
totals
21Second International Symposium on Nuclear Power Plant Life Management15-18 October 2007, Shanghai, China
ORIGENX: Reactor Biological Shield Gamma Power (W/g) after 40 years operation time
1,00E-15
1,00E-14
1,00E-13
1,00E-12
1,00E-11
1,00E-10
1,00E-09
1,00E-08
0 10 20 30 40 50 60 70 80 90 100decay time
spec
ific G
amma
Powe
r W/g
SC 46
MN 54
FE 59
CO 58
CO 60
EU152
totals
Eu-152
22Second International Symposium on Nuclear Power Plant Life Management15-18 October 2007, Shanghai, China
Summary and conclusions� Satisfying validation of the GRS AAA Burn-up -, Shielding- and Activation-
Sequence with the main codes OREST, 2d DORT, GRSAKTIV and GRS-ORIGENX
� Tested against experiments of activated structure material steel and concrete� Application to operation life time up to 40 years PWR of 3000 MW thermal
power� Most important radioactive isotopes and gamma emitters analyzed up to
100 years cooling time after shutdown� Problematic isotopes (Co-58, Ar-37) and trace elements (Co, Eu) identified� Further full documented activation experiments and applications needed
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