Improved Neutron Monitor Systems for Savannah River Site Separations Facilities.

摘要

The Savannah River Laboratory (SRL), in conjunction with Savannah River Site (SRS) Separations Technology personnel, has developed and implemented a comprehensive program to improve the performance and reliability of neutron detector systems (neutron monitors) in the SRS separations areas. The neutron monitors, which monitor the buildup of fissile material in the mixer-settler banks of the solvent extraction process, are important nuclear safety control devices. A review of the performance history of the neutron monitors reveals that many of the systems exhibit problems arising from several causes, including: low neutron sensitivity, high susceptibility to electromagnetic interferences (due to long cable runs between detectors and their electronics), and high maintenance requirements. To address these problems, the neutron monitor improvement program encompasses both technical and administrative improvements, including: substitution of more sensitive neutron monitors at many locations in the solvent extraction areas, the development of an integrated preamplifier/amplifier package to eliminate long cable runs, and improvements in the neutron monitor functional test procedures to reduce maintenance requirements. The implementation of these improvements, already partially complete, is expected to provide enhanced operation and reliability for the neutron monitors. This paper will present a description of the solvent neutron monitors as well as technical details of the improvement program. 2 refs., 5 figs., 1 tab.