Small Column Ion Exchange Monitor System Final Report

CASELLA, VITO

Savannah River Site (S.C.)

关键词: Radiation Monitors;    Decay;    Cesium-137;    Monitors;    Ion Exchange;   

DOI  :  10.2172/835547
RP-ID  :  WSRC-RP-2004-00615
RP-ID  :  AC09-96SR18500
RP-ID  :  835547

美国|英语

来源: UNT Digital Library

【 摘 要 】

A Small Column Ion Exchange (SCIX) system has been designed by the Oak Ridge and Savannah River National Laboratories (ORNL and SRNL) as a potential way to reduce Cs-137 concentrations in high-level radioactive waste at the Savannah River Site. SRNL was asked to develop gamma-ray monitors at six locations within the SCIX system. Gamma-ray monitors are required to verify the proper operation of the ion exchange system, detect cesium breakthrough, and confirm presence of cesium before and after used resin is transferred to a grinder module. The only observable gamma ray in the decay of Cs-137 is from its short-lived Ba-137m daughter. Chemical processes, such as the SCIX, may disrupt the secular equilibrium between this parent-daughter pair; meaning that measurement of Ba-137m will not necessarily yield information about Cs-137 content. While this is a complicating factor that can not be ignored, it is controllable by either: allowing sufficient time for equilibrium to be reestablished (about 20 minutes), or by making multiple measurements with sufficient statistical precision to determine the extent of disequilibrium. The present work provides a means of measuring the Cs-137 and Ba-137m by taking multiple measurements in a process isolation loop that contains the process solution of interest.