Studying of Influence of neutron irradiation on element contents and structures of aluminum alloys SAV-1 and AMG-2.

Transcription

1 Studying of Influence of neutron irradiation on element contents and structures of aluminum alloys SAV-1 and AMG-2. By S. Baytelesov

2 INSTITUTE OF NUCLEAR PHYSICS UZBEKISTAN ACADEMY OF SCIENCES

3 History Establishment of INP of Academy of Sciences 1959 Research reactor & gamma facility started it s s operation Cyclotron У-150-began working Government Enterprise «Radiopreparat» was created Scientific Industrial Enterprise «Tezlatgich» was established Cyclotron У-115 was build

4 Nuclear Facilities Nuclear reactor WWR-SM Cyclotron У150 Cyclotron У115 Neutron generator Gamma facility

5 Developed Technologies I. Cyclotrons radionuclides: Co-57, Zn-65, Ga-67, Ge-68, Pd-103, Ce-139 II. Reactors radionuclides: P-32, P-33, P S-35, S Cr-51, Mn-54, Fe-55, Co-58, Co-60, Mo-99, Y-Y 90, I-125, I I-131, I Pm-147, Ta-182, W-188 W III. Generators of radionuclide : Ge-68 Ga-68, Mo-99 Tc-99m, Sn-113 In-113m W-W 188 Re-188 Planned for future Ir-192, 153Sm, Lu-177, Cs-131, Fe-59

6 WWR-SM Reactor Power 10 MW Maximal thermal neutron in Be-re flux nsm 2 /s. Fast in Be re nsm 2 /s. Max fast in FA nsm 2 /s. Vertical channels 43, Horizontal 9. Thermal column-1 Exploitation of the reactor WWR-SM was planned till Material science Activation analysis, Radiochemistry Nuclear physics Nuclear spectroscopy Radioisotopes production Irradiation of natural minerals TESTING NEW FUEL ASSEMBLIES Personnel training and education Reactor operation hours

7 Taking into consideration development of international programs for reduction of fuel enrichment in research reactors, it was decided to convert the WWR-SM reactor from IRT-3M (36% enriched) fuel to IRT-4M (19.7% enriched) fuel. HEU(36%) IRT-3M Conversion of WWR-SM reactor from use of HEU fuel to use of LEU fuel Parameter 6-Tube IRT-3M 6-Tube IRT-4M Dispersant UO 2 -Al UO 2 -Al Wt. % 235 U (gu/cm 3 ) meat VF D, % U/FA, g H meat, cm T meat, mm T clad, mm T coolant, mm Vol meat, cm Temperature clad 100 C 98 C LEU (19.7%) IRT-4M

8 Active core model of the WWR-SM reactor IRT-2D, WIMS, MCNP-4C, PLTEMP and PARET codes were used for analyses.

9 Description of monitors % Е п, MeV T 1/2 Е, KeV M,mg 197 Au(n,γ) 198 Au d 5 58 Ni(n,p) 58 Co 67,88 2,6 71,3d 810,8(99) 12,25 24 Mg(n,p) 24 Na 78,7 6,3 15,05h 1368,5(100) Ti(n,p) 48 Sc 73,94 7 1,83d 1312,1(100) 1037,4(100) 983,5(100) Ti 46 (n,p)sc 46 7, ,89d 889,2(100) 1120,5(100) Fe 54 (n,p) Mn 54 5, ,6d 834,8(100) 9,05 89 Y(n,2n) 88 Y ,1d 898(92) 1836,1(100) Ni 60 (np)co 60 26,23 6 5,26y 1173,2(100) 1332,5(100) 12,25

10 Experiment results of fast neutron flux in the reactor (Ni-58, optical # absorption) # channels Ni optical absorption

11 Measurement of neutron flux spectrum Monitors Au, Co, Ni, Ti, Fe have been made from thin roll flat metal foil, and Y and Mg were taken in the form of their connections MgO and Y2O3. Two sets of monitors have been weighed, packed into polyethylene packages, wrapped in aluminum foil and soldered in quartz ampoules. One of ampoules has been soldered in Cd glass for cut-off by component thermal flux in the course of irradiation of monitors. Irradiation of both containers was carried out consistently in the current of 2 hours in the second channel of the reactor general neutrons flux. Measurement of samples gamma activity was carried out in days after irradiation. Registration of samples gamma spectrum was carried out on HP Ge detector with multichannel analyzer DSA1000 of Canberra firm, processing of gamma spectrum was carried out by means of standard software package Genie Neutron flux n/sm 2 *s Neutron energy MeV

12 Calculation results neutron flux spectrum # Channel Energy MeV Flux n/sm2*s 0-6,2500E-07 1,33244E+14 6,2500E-07-8,0000E-01 3,95490E ,0000E-01-3,0000E+00 7,47058E+12 3,0000E+00-2,0000E+01 1,81057E+12 Total 1,82074E ,2500E-07 1,97076E+14 6,2500E-07-8,0000E-01 1,36796E ,0000E-01-3,0000E+00 3,20508E+13 3,0000E+00-2,0000E+01 8,09698E+12 Total 3,74019E ,2500E-07 1,54672E+14 6,2500E-07-8,0000E-01 1,33735E ,0000E-01-3,0000E+00 3,31201E+13 3,0000E+00-2,0000E+01 8,57388E+12 Total 3,30102E+14

13 Definition of crystal structure and parameter of a lattice of alloys was spent on X-ray X diffract meter DRON-3М (l = nanometers). According to the radiographic analysis as expected, initial alloys SAV-1 1 and AMG-2 2 have face-centered centered cubic arrangement with lattice parameter, a = ± Å and a = ± Å, accordingly. Small increase of alloys lattice parameter in comparison with the reference aluminum sample ( Å) ) is result from the presence of impurity in them.

14 Definition of element structure and metallographic analysis of investigated i samples was carried out in X-ray X micro analyzer "Jeol" Jeol" " JSM 5910 IV - Japan. Relative contents of basic elements (in %) in hand-picked points of SAV-1 1 and AMG-2 2 samples before and after irradiation with different fluences samples А1 Mg Si Mn Fe С u total SAV-1 NO Ir 98,27 1,06 0,50 0,01 0,14 0, AMG-2 96,57 2,80 0,10 0,24 0,25 0, SAV n/sm 2 97,77 0,82 1,10 0,01 0,28 0, AMG-2 96,15 2,4 0,90 0,24 0,26 0, SAV n/sm 2 97,32 0,62 1,75 0,30 0, AMG2 95,74 2,02 1,70 0,23 0,25 0, SAV-1 AMG n/sm 2 97,09 95,43 0,53 1,85 2,05 2,16 0,24 0,32 0,24 0,01 0, SAV-1 AMG n/sm 2 96,86 95,27 0,45 1,68 2,35 2,52 0,22 0,33 0,23 0,01 0,

15 From the table it is clear, that after irradiation various fluence redistribution of concentration of basic elements in the chosen points is observed. Smashing and dispersion of local insoluble intermetallic phases under reactor influence to radiation, finally leads to essential change of element structure in the measured points, as it is shown in the table.

16 Structure SAV-1, not irradiated In raster pictures of basic elements before irradiation it is shown their non- uniform distribution on all volume of alloys where local formations in the form of white stains insoluble intermetallic phases of system Al-Mg Mg-Si- Fe with the sizes mkm.

17 Microstructure of SAV-1 1 alloy after irradiation with n/sm 2 fluence

18 According to the analysis of raster pictures of basic elements, after irradiation to fluences n/sm 2 local insoluble intermetallic system Al-Mg Mg-Si- Fe phases are shattered and dissipate on the sample, becoming practically uniform. Especially on raster pictures of elements Mg and Si. After irradiation fluence n/ sm 2 the sizes of intermetallic system Al-Mg Mg-Si-Fe phases become not more than 0, 5-2mkm. 5

19 Apparently, after irradiation ageing process is slowed essentially down because of steady dislocation grids formed at the expense of scattered micro inclusions and radiating defects. From drawings it is clear, that after irradiation on surfaces of sample SAV-1 1 the volume of oxide connections (stain of black color) increases in comparison with not irradiated ones. Similar pictures are observed both for AMG-2 2 alloys.

20 Microhardness measurements Microhardness measurement shows, that it is observed strong enough dependence Н µ from weight to value F 3 N. On weights F> 3 N microhardness practically does not depend on weight. As depth of penetration of diamond pyramid depends on weight, it is possible to draw a conclusion, that in surface layer of samples at microhardness definition, apparently plays essential role.

21 Neutron irradiated SAV-1 1 alloy samples microhardness (Н µ) dependence weight on indentor: : not irradiated (1); irradiated by fluences sm 2 (3) and sm 2 (2) Weight F-Newton

22 Neutron irradiated AMG-2 2 alloy samples microhardness (Н µ) dependence from weight on indentor: : not irradiated (1); irradiated by fluences cm 2 (2) and cm 2 (3) Weight F-Newton

23 Microhardness change of samples depending on fluence in graphical view are resulted in drawing microhardness Essentially increase of size after irradiation fluence n/sm 2 and rather poorly linearly grows at the further increase fluence almost in all range of weight F> 3 N, that microhardness essentially increases at the first irradiation. Essential reduction of the sizes (smashing) and dispersion of local insoluble intermetallic phases on big volume of alloys after irradiations and radiating defects, on the visible lead to additional fastening of dispositions that causes increase in microhardness of samples. AMG-2 and SAV-1 alloys microhardness dependence from neutron fluence. Points marked for comparison corresponding to Hµ values of not irradiated AMG-2 and SAV-1

24 Conclusion Influence of reactor irradiations various fluences ( n/sm 2 ) on a microstructure and microhardness of alloys SAV-1 and AMG-2 is studied. It is revealed, that reactor irradiation leads to practically uniform redistribution of the basic impurity on all sample, before irradiation there was non-uniform distribution in initial samples because of natural ageing. In the interval we have found fluence swelling is insignificant. It is established, that under the influence of irradiation microhardness of alloys essentially increases at primary irradiation before fluence n/sm 2 and linearly grows at the further increase fluences to n/sm 2. The microhardness increase results from smashing and dispersion local insoluble intermetallic system Al-Mg-Si- Fe phases on great volume of alloys and growth of concentration of radiation defect with increase of fluence.

25 Thank you