Exposure Inhomogeneity From 241am and 90sr/90y Sources in Terms of the Eye Lens Monitoring in the Nuclear Facilities

Abstract

This article highlights the issues of exposure inhomogeneity that are relative to eye lens monitoring for low-energy photons from 241Am and beta-rays from 90Sr/90Y including a personal protective equipment because eye lens exposure has been concerned more than before due to the proposed reduction of relevant dose limit. These nuclides are common and concerned sources in the nuclear industry. Our previous study presented a quantitative estimation of exposure inhomogeneity, which was applied to simple but typical exposure situations. For the present study, exposure inhomogeneity of 241Am was approximately within a factor of 1.6, implying a more homogeneous situation than expected. Regarding 90Sr/90Y exposure, estimation from both Hp(10) and Hp(0.07) on trunk would lead to an over- or underestimation by a factor of more than 10. In contrast, Hp(3) measurement on trunk will improve by up to a factor of 2. With respect to the personal protective equipment, lead apron and protective glasses are effective for the 60-keV photons for both anterior-posterior and rotational irradiations, while a full-face respirator can reduce the eye lens dose by approximately 17% for 90Sr/90Y betas. As a whole, this study demonstrated that the effect of protective equipment could be effectively incorporated into the homogeneity evaluation.

Suit Up: A Systematic Review of the Personal Protective Equipment (PPE) Recommended and Utilized by Various Classes of Responders to Nuclear Radiological Disasters at Nuclear Power Plants

“… 22 Protective glasses were helpful in shielding the eye lenses from high-exposure doses. 31 Canu also echoed the requirement of protective goggles for fuel workers. However, these anti-spray googles were reported among the least used PPE by the workers.…”

“…However, its protective qualities also decreased as the exposure to beta or gamma particles increased. 31 The protective ability of aprons was also identified where workers perform tasks with heat or power tools that may generate debris. Donning an apron over an air-fed suit reduced the probability of damaging the suit.…”

“…Yoshitomi and Kowatari noted that while full-face respirators may provide some shielding properties to the eyes, it may not be suffiecient. 31 Kozlovska, et al also noted that the protective qualities of some of the gear available for responders decreased depending on the level and length of their exposure. 19 To compound this issue of insufficiency, workers do not always don nor doff their gear successfully or completely.…”