Various Radioactive Exposure Pathways Determination for TiO2 Production - Case Study

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F70565813%3A_____%2F17%3AN0000007" target="_blank" >RIV/70565813:_____/17:N0000007 - isvavai.cz</a>

Result on the web

<a href="http://www.npl.co.uk/upload/pdf/20171002-05_eu_norm_otahal.pdf" target="_blank" >http://www.npl.co.uk/upload/pdf/20171002-05_eu_norm_otahal.pdf</a>

DOI - Digital Object Identifier

—

Result language

angličtina

Original language name

Various Radioactive Exposure Pathways Determination for TiO2 Production - Case Study

Original language description

The increase of the natural radionuclides concentration may happen in some parts of the titanium dioxide production during the treatment process. Since uranium and thorium oxides are soluble in hot sulphuric acid, most of the uranium and thorium remains in solution during the hydrolysis in the hydrolysis vessels. Due to the technological renovation of production lines, it had to dismantle three vessels used for the hydrolysis process. Four main exposure pathways were identified before starting of production lines renovation: a) contribution caused by external exposure, b) contribution of internal exposure via the inhalation of the radon decay products, c) contribution of the internal exposure via the inhalation of thoron decay products and d) contribution of the internal exposure via the inhalation of the long-lived radionuclides belonging to the uranium and thorium decay series emitting the alpha particles. This paper describes the individual steps of the workplace monitoring, personal monitoring, and environmental monitoring as a part of radiation protection. The air quality control during the workplace monitoring was based on the air sampling in vessels and their vicinity. The measurement system, after the air sampling, allows the determination of the Equilibrium-Equivalent Radon Concentration, Pb-212 concentration, and concentration of the long-lived alpha emitters. The radon concentration was monitored by continuous radon monitor in the 30 minutes measurement step in the vessel's vicinity. The gamma dose rate was operatively measured in the vessels and their vicinity. The personal monitoring of workers who dismantled the vessels was performed by personal dosimeter OD88a. This personal dosimeter is designed to be worn on the belt and is made up of an air pump, battery, and sampling head for determination of the radon decay products concentration and the long-lived alpha emitters’ concentration time integrals. The external gamma radiation dose was determined by Optically Stimulated Luminescence dosimeters. For environmental monitoring, the active integral measuring device was used for the radon decay products concentration estimation. The total effective dose of workers who dismantled the vessels was calculated based on the personal monitoring. This one represented the conservative estimation due to disregarding of the personal protective equipment impact. The determination of Pb-212 concentration was verified by alpha spectrometric measurement in some cases. The other measuring methods were metrologically verified.

Czech name

—

Czech description

—

Type

O - Miscellaneous

CEP classification

—

OECD FORD branch

10304 - Nuclear physics

Project

—

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2017

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů