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Title: TRIPLICATE SODIUM IODIDE GAMMA RAY MONITORS FOR THE SMALL COLUMN ION EXCHANGE PROGRAM

Abstract

This technical report contains recommendations from the Analytical Development (AD) organization of the Savannah River National Laboratory (SRNL) for a system of triplicate Sodium Iodide (NaI) detectors to be used to monitor Cesium-137 ({sup 137}Cs) content of the Decontaminated Salt Solution (DSS) output of the Small Column Ion Exchange (SCIX) process. These detectors need to be gain stabilized with respect to temperature shifts since they will be installed on top of Tank 41 at the Savannah River Site (SRS). This will be accomplished using NaI crystals doped with the alpha-emitting isotope, Americium-241({sup 241}Am). Two energy regions of the detector output will be monitored using single-channel analyzers (SCAs), the {sup 137}Cs full-energy {gamma}-ray peak and the {sup 241}Am alpha peak. The count rate in the gamma peak region will be proportional to the {sup 137}Cs content in the DSS output. The constant rate of alpha decay in the NaI crystal will be monitored and used as feedback to adjust the high voltage supply to the detector in response to temperature variation. An analysis of theoretical {sup 137}Cs breakthrough curves was used to estimate the gamma activity expected in the DSS output during a single iteration of the process. Count rates arisingmore » from the DSS and background sources were predicted using Microshield modeling software. The current plan for shielding the detectors within an enclosure with four-inch thick steel walls should allow the detectors to operate with the sensitivity required to perform these measurements. Calibration, testing, and maintenance requirements for the detector system are outlined as well. The purpose of SCIX is to remove and concentrate high-level radioisotopes from SRS salt waste resulting in two waste streams. The concentrated high-level waste containing {sup 137}Cs will be sent to the Defense Waste Processing Facility (DWPF) for vitrification and the low-level DSS will be sent to the Saltstone Production Facility (SPF) to be incorporated into grout.« less

Authors:
Publication Date:
Research Org.:
SRS
Sponsoring Org.:
USDOE
OSTI Identifier:
1025516
Report Number(s):
SRNL-STI-2011-00510
TRN: US1104980
DOE Contract Number:  
DE-AC09-08SR22470
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; 36 MATERIALS SCIENCE; ALPHA DECAY; CALIBRATION; CESIUM 137; FEEDBACK; ION EXCHANGE; MAINTENANCE; MONITORS; RADIOISOTOPES; SAVANNAH RIVER PLANT; SENSITIVITY; SHIELDING; SODIUM IODIDES; STEELS; TANKS; TESTING; VITRIFICATION; WASTE PROCESSING; WASTES

Citation Formats

Couture, A. TRIPLICATE SODIUM IODIDE GAMMA RAY MONITORS FOR THE SMALL COLUMN ION EXCHANGE PROGRAM. United States: N. p., 2011. Web. doi:10.2172/1025516.
Couture, A. TRIPLICATE SODIUM IODIDE GAMMA RAY MONITORS FOR THE SMALL COLUMN ION EXCHANGE PROGRAM. United States. doi:10.2172/1025516.
Couture, A. Tue . "TRIPLICATE SODIUM IODIDE GAMMA RAY MONITORS FOR THE SMALL COLUMN ION EXCHANGE PROGRAM". United States. doi:10.2172/1025516. https://www.osti.gov/servlets/purl/1025516.
@article{osti_1025516,
title = {TRIPLICATE SODIUM IODIDE GAMMA RAY MONITORS FOR THE SMALL COLUMN ION EXCHANGE PROGRAM},
author = {Couture, A.},
abstractNote = {This technical report contains recommendations from the Analytical Development (AD) organization of the Savannah River National Laboratory (SRNL) for a system of triplicate Sodium Iodide (NaI) detectors to be used to monitor Cesium-137 ({sup 137}Cs) content of the Decontaminated Salt Solution (DSS) output of the Small Column Ion Exchange (SCIX) process. These detectors need to be gain stabilized with respect to temperature shifts since they will be installed on top of Tank 41 at the Savannah River Site (SRS). This will be accomplished using NaI crystals doped with the alpha-emitting isotope, Americium-241({sup 241}Am). Two energy regions of the detector output will be monitored using single-channel analyzers (SCAs), the {sup 137}Cs full-energy {gamma}-ray peak and the {sup 241}Am alpha peak. The count rate in the gamma peak region will be proportional to the {sup 137}Cs content in the DSS output. The constant rate of alpha decay in the NaI crystal will be monitored and used as feedback to adjust the high voltage supply to the detector in response to temperature variation. An analysis of theoretical {sup 137}Cs breakthrough curves was used to estimate the gamma activity expected in the DSS output during a single iteration of the process. Count rates arising from the DSS and background sources were predicted using Microshield modeling software. The current plan for shielding the detectors within an enclosure with four-inch thick steel walls should allow the detectors to operate with the sensitivity required to perform these measurements. Calibration, testing, and maintenance requirements for the detector system are outlined as well. The purpose of SCIX is to remove and concentrate high-level radioisotopes from SRS salt waste resulting in two waste streams. The concentrated high-level waste containing {sup 137}Cs will be sent to the Defense Waste Processing Facility (DWPF) for vitrification and the low-level DSS will be sent to the Saltstone Production Facility (SPF) to be incorporated into grout.},
doi = {10.2172/1025516},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2011},
month = {9}
}

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