Evaluation of ANSI N42-17A by investigating the effects of temperature and humidity on the response of radiological instruments

摘要

The American National Standards Institute (ANSI) N42.17A-1989 standard's performance criteria and test methods has been evaluated by investigating the effects of temperature and humidity on the response of 105 portable direct-reading radiological instruments (45 beta-gamma survey meters, 32 neutron rem meters, 1O alpha contamination and 18 tritium-in-air monitors). The US Department of Energy (DOE) mandates the use of ANSI standards for the calibration and performance testing of radiological instruments, and requires that instruments be appropriate for existing environmental conditions. Random tests conducted in an environmental chamber determined the effects of temperatures ranging from (minus)10(degree)C to 50(degree)C and humidity at levels of 40% RH and 95% RH on the response of a cross section of instruments used in routine health physics operations at Los Alamos. The following instruments were tested: Eberline RO-2 and RO-C ionization chambers, Eberline E-530 survey meter with the Model HP-C stainless steel Geiger-Muller (G) wall probe, Eberline PIC-6A and PIC-6B ion chambers, Eberline ESP-1 survey meter with the Model HP-260 pancake G detector, Ludlum 3 survey meter with the Model 44-6 stainless steel G wall probe, Eberline ESP-1, ESP-2 and PAR-4 survey meters with the neutron rem detector, Health Physics Instruments 2080 survey meter with the moderator detector, Ludlum 139 survey meter with the Model 43-32 air-proportional alpha detector, and the Overhoff 394-C, Johnston J-111 and J-110 tritium monitors. Experimental results encompass 1128 temperature tests (1269-hours exposure in the chamber) and 735 humidity tests (1890-hours exposure in the chamber). The study shows the standard's test requirement for temperature at or near the extreme conditions, and the standard's test requirement for humidity at 95% RH may be too restrictive for instruments used in the work environment.