Is multiple dosimeters a necessity for evaluating effective dose

Compact Reprocessing of Advanced fuels in Lead cells (CORAL) facility, has successfully reprocessed the spent fuel from FBTR which has undergone a maximum burn-up of 155GWD/t. During the course of its operation many of the operation and maintenance jobs, which were to be done with close proximity to the source has led to increased collective dose to the plant personnel. Augmentation of shielding for glove boxes and shadow shields in fume hoods was adopted as one of the remedial measures in order to minimize the radiation field and consequent exposures. Though this has reduced the radiation field in and around the operating area, has resulted in a non uniform radiation field and exposures to the workers, suggesting the study to establish the need for adopting use of multiple dosimeters for evaluating the exposures. ANSI also recommends the utility to study the degree of non uniformity in the exposure to establish the need for use of multiple dosimeters to evaluate the effective dose. In view of this, a study was conducted at various locations of the CORAL facility wherein non uniform radiation fields exist and the findings are presented in this paper