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Indian Journal of Pure & Applied Physics (IJPAP) >
IJPAP Vol.50 [2012] >
IJPAP Vol.50(07) [July 2012] >
| Title: | Shield design for a hull neutron monitor using Monte Carlo techniques |
| Authors: | Anand, S
Singh, Kapil Deo
Sharma, V K |
| Keywords: | Gamma
Neutron
Shield
Design
Hull monitor
Safety |
| Issue Date: | Jul-2012 |
| Publisher: | NISCAIR-CSIR, India |
| Abstract: | In the head-end process of a reprocessing plant, the spent fuel is chopped
using a mechanical chopper into small pieces and the heavy metal oxide is
leached in nitric acid leaving behind the undissolved zircaloy clad (hull) in
the basket. The hull mass needs to be estimated for the residual actinides and
fission products to check for the completion of dissolution and also for the
purpose of nuclear material accounting. This is normally carried out by gamma
spectroscopy for the residual fission products. A new method is proposed based
on active/passive neutron measurements of the residual actinides. The basket
along with the hull is moved to a corner of the dissolution cell using remote tools,
where the hull monitoring exercise will be carried out. Hence, shielding around
this basket is required in this area to limit the dose rate to a value
acceptable (i) for the operating personnel engaged in monitoring, and (ii) for 3He
detectors used to measure neutrons. It has been proposed that the acceptable
dose rate criteria at this detector location should be less than 1.74 mGy/hr
(200 mR/hr). ORIGEN2 code is used to calculate the gamma and neutron emission
rate from the residual spent fuel and the clad material in the hulls. Shielding
code based on Monte Carlo technique is used
for the gamma and neutron shielding calculations. In this paper, calculations
are carried out for each of the shield material considered, and it is found
that the shielding thickness required to bring down the dose rate to 1.74
mGy/hr is 12.5 cm for lead or 21 cm for iron. |
| Page(s): | 527-530 |
| CC License: |  CC Attribution-Noncommercial-No Derivative Works 2.5 India |
| ISSN: | 0975-1041 (Online); 0019-5596 (Print) |
| Source: | IJPAP Vol.50(07) [July 2012]
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