Methods for Tritium Production Rate Measurement in Design-Oriented Blanket Experiments

Direct and indirect methods have been developed for measurements of tritium production rates on different Li isotopes. The methods are mainly intended for design-oriented blanket experiments and are based on the activation of thin diagnostic pellets. In the direct method, the tritium activity bred from Li isotopes can be evaluated separately using two activated Li-containing pellets, measured by liquid scintillation counting. The method allows precise measurements of tritium activity in the pellet at a level of 2 Bq/g. The indirect method is based on the use of model activation reactions, ³⁵Cl(n,)³²P and ³¹P(n,)³²P, that possess a similar neutron spectrum sensitivity as direct tritium production reactions on ⁷Li and ⁶Li, respectively, and an effective measurement of the activation product of model reactions, ³²P, by Cherenkov radiation counting. The reaction rate of model reactions can be calibrated in order to obtain the TPR.