Sains Malaysiana 37(4):  401-404 (2008)

 

Assessment of Neutron Flux Gradients in Irradiation Channels at the

TRIGA Reactor by Au-Cr-Mo Monitor Set Based on k₀-INAA

(Penilaian Tentang Kecerunan Fluks Neutron Dalam Saluran Penyinaran di Reaktor

TRIGA Dengan Set Pemonitor Au-Cr-Mo Berdasarkan k_o-APNI)

 

Khoo Kok Siong & Ti Kien Leong

Nuclear Science Programme

School of Applied Physics, Faculty of Science and Technology

Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia

 

 

Sukiman Sarmani & Amran Majid

Chemistry Programme, School of Chemical Sciences & Food Technology

Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia

 

Received:  4 January 2008 / Accepted:  4 April 2008

 

ABSTRACT

A gradient of neutron flux distribution in an irradiation channel in research reactor is considered to have effect on the k₀-instrumental neutron activation analysis (k₀-INAA) measurement. A study has been carried out to determine: (1) the variation of the thermal to epithermal neutron flux ratio (f); (2) the epithermal neutron flux shape factor (α), and (3) the neutron flux in an irradiation container at four selected irradiation channels, use being made of an Au-Cr-Mo monitor set. In this work, f was found to range from 15.5 – 16.3, while α was found to range from 1.52 x 10^-2 – 5.58 x 10^-2. Additionally, within the selected irradiation channels the variation in calculated thermal neutron flux within one irradiation container was found to vary from 11.8% - 26.7%. The results of analysis have provided a determination of variation in the neutron parameters, f and α, and neutron flux between the irradiation channels and within the irradiation container.

 

Keywords: k₀-INAA; neutron flux distribution; neutron parameters

 

 

ABSTRAK

 

Kecerunan taburan fluks neutron pada saluran penyinaran dalam reaktor penyelidikan boleh memberikan kesan kepada pengukuran analisis pengaktifan neutron instrumentasi k₀ (k₀-APNI). Satu kajian telah dilakukan untuk menentukan: (1) variasi nisbah fluks neutron terma kepada fluks neutron epiterma (f); (2) faktor pembentukan fluks neutron epiterma (α), dan (3) fluks neutron dalam satu bekas penyinaran pada empat saluran penyinaran terpilih dengan menggunakan set pemantau Au-Cr-Mo. Dalam kerja ini, f adalah dalam julat 15.5 – 16.3 dan α menunjukkan julat di antara 1.52 x 10^-2 – 5.58 x 10^-2. Tambahan, variasi fluks neutron terma yang dikira dalam satu bekas penyinaran mempunyai perbezaan dari 11.8% - 26.7% pada saluran penyinaran terpilih. Keputusan analisis membuktikan terdapat variasi dalam parameter neutron, f dan α, serta fluks neutron di antara saluran penyinaran dan dalam bekas penyinaran.

 

Kata kunci: k₀-APNI; taburan fluks neutron ; parameter neutron        

 

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