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

1st RCM, 2005 Jonah

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

1st RCM, 2005 Jonah

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

1st RCM, 2005 Jonah

1st RCM, 2005 Jonah

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

1st RCM, 2005 Jonah

10

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

1st RCM, 2005 Jonah

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

1st RCM, 2005 Jonah

10

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 _

1st RCM, 2005 Jonah

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

1st RCM, 2005 Jonah

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

1st RCM, 2005 Jonah

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 -

1st RCM, 2005 Jonah

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

1st RCM, 2005 Jonah

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