[en] The FBTR fuel pins fabricated are subjected to different nondestructive inspection to ensure conformance to the stringent user specifications, required for optimum performance of these elements in the reactor. Nondestructive assay (NDA) techniques for estimating the quantities of special nuclear material are normally used for purposes of safeguards and security of nuclear material. These assay techniques have been developed for RMD, BARC for application in the inspection of FBTR fuel pins being fabricated for the FBTR, India. In order that these NDA techniques be applicable for purposes of quality control, the sensitivity and resolution of the radiometric techniques of gamma and neutron counting have been developed to provide accuracies of better than 2%. The NDA methods have been used to ensure the uniformity of enrichment of the fuel pellets in the fuel pin and to estimate the total element content in individual pins. This paper gives a brief description of the techniques and results of the large number of fuel pins assayed. (author)

[en] Several techniques are available for the measurement of high neutron fluence. The major problem for measuring low neutron fluence using CR-39 detectors is the inherent and unpredictable background on the films. This problem can be overcome, considerably, by using a method of obtaining coincidence tracks in two detector films that are kept in close contact during irradiation. The technique developed has enabled the measurement of neutron fluence as low as 3.5x10⁴ n/cm² and reduction in background track density is by a factor of 30. The details of the technique and results are presented in this paper. (author)