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THE DETERMINATION OF SOLUBLE POISON CONCENTRATIONS IN H$sub 2$O (thesis)

Technical Report ·
OSTI ID:4141564

A soluble poison is a water soluble chemical compound which possesses a high thermal neutron absorption cross section. It is added to the water moderator of a boiling reactor for certain control purposes. A method is described which will continuously monitor the concentration of the poison in the moderator. The theory of operation follows that of the transmission principle in which a neutron beam is attenuated by the medium through which it passes. Poisoned moderator is circulated through a small tank surrounded by paraffin while a BF/sub 3/ proportional counter detects neutrons which diffuse through the water from a Po-Be neutron source. The relationship between counting rate and poison concentration is essentially linear in the concentration range which is considered (0 to 0.008 molar boric acid). Calibration of several counter arrangements and positions is presented. Data are given for effects of temperature, liquid level, and amount of poison on counting rate. Three poisons, gadolinium, cadmium, and boron were used in the experiment. This analytical method can yield results commensurate with counting error which will decrease as counting time is increased. One drawback of using BF/sub 3/ proportional counters is that their operating characteristics shift with high counting rates and care must be taken to insure operation on the proper plateaus. Accuracies approaching 1% have been attained which can be achieved with the continuous arrangement proposed. (auth)

Research Organization:
Argonne National Lab., Ill.
NSA Number:
NSA-14-018865
OSTI ID:
4141564
Report Number(s):
TID-6143
Country of Publication:
Country unknown/Code not available
Language:
English