Borosilicate glass raschig rings as neutron absorbers - ANS 8.5

A number of American National Standards Institute (ANSI) standards have been prepared that provide guidance for the prevention of criticality accidents in the handling, storing, and processing of fissionable materials. Standard ANSI/ANS-8.5-1986 provides guidance for the use of borosilicate glass Raschig rings in criticality prevention in the storage and processing of fissil solutions. The standard is now under a new prescribed 5-yr review. The changes in the proposed revision to specific analysis methods for Raschig ring properties have been removed. Second, emphasis has been placed on requirements for use of controlled sample rings and trending of operational data to determine the frequency of maintenance tests of the ring properties. Both changes reflect up-to-date concepts in ensuring the criticality safety of vessels pack with Raschig rings. Required properties of Raschig rings are specified as criteria for acceptance. The techniques used to measure values of these criteria are determined by the user. Justification for the use of a specific measurement technique shall be documented and independently reviewed for applicability and technical validity. For reference, measurement techniques acceptable without justification, for the purposes of this standard, appear in an appendix. All of these measurement techniques are national consensus standards