Performance testing of in-sodium sensors and simulated experiments in, sodium chemistry loop

• Sodium chemistry loop operated with simulated reactor conditions.
• Electrochemical sensors for measurement of H2, C and O2 in sodium tested.
• Hydrogen sensor response studied by Na–NaOH and Na–H2O reactions.
• Hydrogen and oxygen sensors response tested for cold trap temperature variation.

Impurities like oxygen, hydrogen and carbon in sodium circuits of fast reactors need to be monitored and controlled within permissible levels. Toward this, electrochemical sensors are being developed in this Center for continuous monitoring of these impurities in sodium. A sodium chemistry loop (SCL), wherein reactor conditions can be simulated, was built and performance of the sensors was studied. The response of the hydrogen sensor for sodium hydroxide addition and simulated steam leak was studied in SCL. The responses of hydrogen and oxygen sensors for the variation of cold trap temperature are also discussed. Carbon activity in sodium was monitored using carbon sensor and foil equilibration technique and the results were used for testing a radionuclide trap, containing reticulated vitreous carbon, for the removal of cesium isotopes in sodium was tested in SCL. The results of these studies are presented in this paper.