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Title: Development and Characteristics of an ANSI/ANS-8-3-1997-Compliant Criticality Alarm

Abstract

A Criticality Alarm System (CAS) was developed at the Savannah River Site (SRS) beginning in 1964, which used an ionization chamber and battery - powered tube amplifier. Three generations of improvements are described here, to improve reliability, reduce maintenance cost, and eliminate false alarms. The original configuration for the CAS instrument (called Nuclear Incident Monitor-NIM model I) was a single chassis containing all components including the batteries and the detector, and a warning bell and light. To decrease the contamination potential of NIMs, the detector can now be removed from the chassis and remotely located for some installations. In the presently used second generation model II, each unit consists of an ion chamber with electrometer amplifier, voltage comparator circuits, battery and power supplies, monitoring circuits, and relay alarm circuits. The electrometer circuit is housed with the ion chamber in an aluminum enclosure. The remaining components are located in the main chassis. An alarm point of one R per Hour is adjustable over a narrow range for calibration purposes. Evacuation zones were determined on a 25 rad dose basis, and then modified to the 12 rad level.

Authors:
Publication Date:
Research Org.:
Savannah River Site (US)
Sponsoring Org.:
US Department of Energy (US)
OSTI Identifier:
799457
Report Number(s):
WSRC-MS-2002-00539
TRN: US0300039
DOE Contract Number:  
AC09-96SR18500
Resource Type:
Conference
Resource Relation:
Conference: ANS 2002 Winter Meeting, Washington, DC (US), 11/17/2002--11/21/2002; Other Information: PBD: 7 Jun 2002
Country of Publication:
United States
Language:
English
Subject:
61 RADIATION PROTECTION AND DOSIMETRY; 46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; ALARM SYSTEMS; RADIATION MONITORS; RADIATION PROTECTION; CRITICALITY; MAINTENANCE; RADIATION MONITORING; RELIABILITY; HISTORICAL ASPECTS; SAVANNAH RIVER PLANT

Citation Formats

McMahan, J.W. Development and Characteristics of an ANSI/ANS-8-3-1997-Compliant Criticality Alarm. United States: N. p., 2002. Web.
McMahan, J.W. Development and Characteristics of an ANSI/ANS-8-3-1997-Compliant Criticality Alarm. United States.
McMahan, J.W. Fri . "Development and Characteristics of an ANSI/ANS-8-3-1997-Compliant Criticality Alarm". United States. https://www.osti.gov/servlets/purl/799457.
@article{osti_799457,
title = {Development and Characteristics of an ANSI/ANS-8-3-1997-Compliant Criticality Alarm},
author = {McMahan, J.W.},
abstractNote = {A Criticality Alarm System (CAS) was developed at the Savannah River Site (SRS) beginning in 1964, which used an ionization chamber and battery - powered tube amplifier. Three generations of improvements are described here, to improve reliability, reduce maintenance cost, and eliminate false alarms. The original configuration for the CAS instrument (called Nuclear Incident Monitor-NIM model I) was a single chassis containing all components including the batteries and the detector, and a warning bell and light. To decrease the contamination potential of NIMs, the detector can now be removed from the chassis and remotely located for some installations. In the presently used second generation model II, each unit consists of an ion chamber with electrometer amplifier, voltage comparator circuits, battery and power supplies, monitoring circuits, and relay alarm circuits. The electrometer circuit is housed with the ion chamber in an aluminum enclosure. The remaining components are located in the main chassis. An alarm point of one R per Hour is adjustable over a narrow range for calibration purposes. Evacuation zones were determined on a 25 rad dose basis, and then modified to the 12 rad level.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2002},
month = {6}
}

Conference:
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