NEUTRON ACTIVATION ANALYSIS WITH THE NIGERIA MNSR (NIRR-1)
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Transcript of NEUTRON ACTIVATION ANALYSIS WITH THE NIGERIA MNSR (NIRR-1)
1st RCM, 2005 Jonah
NEUTRON ACTIVATION ANALYSIS WITH THE NIGERIA MNSR (NIRR-1)
S.A. JonahREACTOR FACILITY SECTION
CENTRE FOR ENERGY RESEARCH AND TRAINING,
AHMADU BELLO UNIVERSITY, ZARIA, NIGERIA
1st RCM, 2005 Jonah
OUTLINE OF PRESENTATION
• INTRODUCTION
• STATUS OF NIRR-1 FACILITIES FOR NAA
• PLAN FOR THE CRP
• PRELIMINARY RESULTS
• DISCUSSION & RECOMMENDATIONS
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INTRODUCTION-NIRR-1 Design Parameters
• No. of fuel rods installed:347 with 3 Al dummies• No of extra fuel rods: 3• Fuel integrity check: periodic gamma ray
spectrometry• Clean Cold Core ρex : 3.77 mk (< 50 cents) • Special Feature: SRR (Cd absorber) ρ =-1.2 mk• Total U-235: 1 kg.• Nominal power: 31 kW• Nominal flux: 1.0 1012 cm-2 s-1.• Uses NAA, Training/Teaching, Research and
limited Isotope Production
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INTRODUCTION-NIRR-1 Parameters for NAA
• NIRR-1 is 8th commercial MNSR • Criticality Feb. 03, 2004• Licensed June 01, 2004• It is designed specifically for NAA and RI• Has 6 irradiation sites connected for NAA• Suitable flux for NAA is 7x1010 – 1x1012 n/cm2.s• Reactor flux stabilizes 15 min after start-up• Radial and axial flux variation around core is 3%• Flux variation inside irradition vial is 1%• Max. Temp., inner site is 55 °C, thus suitable for liquid & biological
samples
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IRRADIATION FACILITIES
• Irradiation via 2 Pneumatic Transfer Systems (A & B)
• A connected to a small inner site (A1)&large outer site (A2)
• B is connected to 3 small inner sites (B1, B2, B3) and a small outer site (B4)
• B is for short and medium irrad. With Channel B1 designed for cyclic NAA
• B can tranfer sample from reactor to det., stripper, Pb box
• A works in auto/manual for long irradiation with a timer
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Reactor Vessel Reactor Core showing some fuel elements
Fig. 1. NIRR-1 Core configuration showing irradiation channels
Control Rod Guide Tube
Annular Beryllium Reflector
Thermocouples Inner Irradiation Channel
Fission Chamber
Support Structure
Outer Irradiation Channel
Reactivity Adjuster
Reactor Core showing some fuel elements
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GAMMA-RAY COUNTING FACILITIES
• GEM Series HPGe Coaxial Detector (GEM-30195), p-type• Resolution is 2.0 keV @ 1.33 MeV, 60Co, HV = +1500 V• Pb shield cuts background and suitable for MARINELLI• 2 sets of plexi-glass sample holders for samp-source posns.• Amp settings adjusted for compatibilty with ‘WINSPAN’• ‘WINSPAN’ performs peak ident., evaluatn; & calc. of
conc.• Efficiency curves have been determined for the sample
holders
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NEUTRON SPECTRUM PARAMETERS OF SLOWPOKE & MNSR
0/)( TTr n0/)( TTr n
Facility Inner irradiation channel Outer irradiation channel
f Tn
(°C)
fF f Tn,fF
MNSR, NIRR-1; Zaria, Nigeria, 90% 235U
19.2 -0.052 0.0459 60.64 5 48.3 +0.029 0.0183 30.41 15
MNSR, GHARR-1; Accra, Ghana, 90% 235U
18.8 -0.104 0.0334 27 _ 49 -0.0261 0.0173 20 _
MNSR, PROTYPE, Beijing, China, 90% 235U
19.8 -0.009 _ _ - 58.5 +0.023 _ _ _
SLOWPOKE-2, DUSR, Halifax, Canada, 90% 235U
18.8 -0.0425 0.0458 38.8 - 57.1 -0.0098 0.0156 33.0 _
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ROUTINE UTILIZATION PROCEDURES
Neutron flux/Irradiation channel
Procedure Tirr Td Tm Activation products
1x 1011 n/cm2.s/Outer irradiation channel (B4)
S1 2m 2-10m 10m 28Al, 27Mg, 38Cl, 49Ca, 66Cu, 51Ti, 52V, 87mSr, 37S, 80Br
S2 2m 3-5h 10m 24Na, 42K, 165Dy, 56Mn, 152mEu, 64Cu, 172Er
5x1011 n/cm2.s/Inner irradiation channel (B2)
L1 6h 2-3d 30m 24Na, 42K, 76As, 68mZn, 122Sb, 82Br, 99Mo, 140La, 153Sm, 198Au, 187W, 166Ho, 239Np(U), 72Ga, 177Lu, 131Ba, 115Cd, 175Yb
L2 6h 10-15d 60m 46Sc, 141Ce, 60Co, 51Cr, 134Cs, 152Eu, 153Gd, 177Lu, 131Ba, 99Mo, 147Nd, 86Rb, 124Sb, 75Se, 182Ta, 160Tb, 233Pa(Th), 169Yb, 65Zn, 115mCd, 59Fe, 85Sr, 110mAg, 187Hf, 95Zr, 170Tm
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CRP PLAN• Improve and validate methods for n-
spectrum parameters– Acquisition of codes (MCNP5, SAND)
• Develop methodologies for accurate measurement of fission neutron ave – Comparison with data libraries
• Re-measure constants (o, Io) for NAA– As specified by CRP
• Testing of the k0-IAEA software– Using CRMs
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PRELIMINARY RESULTS- fission f by single
comparator method
Reaction f (mb)
(f 27Al(n,p)
reaction)
f (mb)
(Io 197Au(n,)
reaction)
CALAMAND (IAEA 1974)
JENDL (2002
27Al(n,p)27Mg 4.200.05 4.170.05 4.00.45 4.284
27Al(n,)24Na 0.9240.035 0.9160.037 0.7250.045 0.688
46Ti(n,p)46Sc 12.50.7 12.40.7 12.50.9 13.1
47Ti(n,p)47Sc 16.60.1 16.50.1 20.02.3 17.75
54Fe(n,p)54Mn 85.54.9 84.84.8 82.55 81.85
58Ni(n,p)58Co 120.05.9 119.05.8 1137 107.2
64Zn(n,p)64Cu 49.72.1 49.32.0 31.02.3 -
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PRELIMINARY RESULTS- Fast neutron flux by threshold reactions
pn,Detector foil Reaction(mb)
Half-life E (keV) f x1011
(cm-2.s-1)
Al-0.1%Au foil; 0.1mm thick, IRRM-530
27Al(n,p)27Mg 4.28 9.46 m 843.761014.43
1.04+0.111.09+0.20
99.99% Al; 0.1 mm thick; GODDFELLOW
27Al(n,p)27Mg 4.28 9.46 m 843.761014.43
1.030.110.970.23
99.0% Ni foil; 0.1mm thick; GOODFELLOW
58Ni(n,p)58m+g Co 107.20 70.86 d 810.77 1.180.21
99.99% Ti foil; 0.125mm thick; GOODFELLOW
47Ti(n,p)47Sc 17.75 3.35 d 159.38 0.990.12
99.99% Fe foil; 1mm thick; GOODFELLOW
54Fe(n,p)54Mn 81.85 312..11 d 834.84 0.960.14
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DISCUSSION & RECOMMENDATIONS
• NIRR-1 is used routinely by relative NAA• MNSRs´n-spec parameters are in-consistent• Cd-covered method with Io(Au) is ok for fiss. ave
• Fast n-spec in MNSR is a pure fission spec• The Al-0.1%Au is ok for fast flux monitoring• Coordinated n-spec charact.program for MNSR• Inter comparison exercises