Keywords: radiation safety, fire detectors, plutonium, americium


Some works in industry are associated with the use of sources of ionizing radiation, both in the form of radioactive isotopes of cobalt, plutonium, americium, cesium, etc., and with the use of special devices such as X‑ray tubes or particle accelerators. Although the share of these works is insignificant in the total volume of production, the handling of sources of ionizing radiation, radioactive substances, in itself requires special attention, careful observance of safety rules, use, if necessary, of personal protective equipment and safe disposal of used devices. In the article, the use of transuranium isotopes in fire detectors (sensors) is separated from the entire complex of activities of this type. A comparative analysis is provided from the point of view of radiation safety of the main isotopes used in sensors – plutonium‑239 and americium‑241. It was established that the distance of alpha particles in the air during the decay of plutonium is 56 mm, and during the decay of americium – 61 mm, which compares with the dimensions of the detector 1151E (diameter 108 mm, height 43 mm). In addition, alpha rays have a very low penetrating ability – several tens of micrometers in body tissues. The activity of plutonium in the IFTP detector is much greater than that of americium 1151E – 570 times. However, from the point of view of disposal, the long-lived Pu‑239 presents a problem, so it is more appropriate to replace it with Am‑241. It is noted that the danger of using americium is its relatively high solubility in water, but it is unlikely that americium from a fire detector will enter the water in a significant amount during normal operation. It was concluded that the use of radioisotope fire detectors with proper operation is quite safe, but it is more appropriate to use the isotope americium.


1. Пожарные извещатели. ИФТП. URL: (дата звернення: 15.11.2022).
2. 1151E – Дымовой радиоизотопный извещатель. TECHPORTAL. URL: (дата звернення: 15.11.2022).
3. Audi G., Bersillon O., Blachot J., Wapstra A.H. The NUBASE evaluation of nuclear and decay properties. Nuclear Physics. 2003. Vol. 729. P. 3–128.
4. Василенко И.Я. Радиоактивный цезий. Природа. 1999. № 3. С. 70–76.
5. Радиоактивные вещества. Америций. URL: (дата звернення: 17.11.2022).
6. Америций-241. URL: (дата звернення: 17.11.2022).
7. Нептуній-237. URL:Нептуній-237 (дата звернення: 17.11.2022).
8. Плутоній-239. URL: (дата звернення: 25.11.2022).
How to Cite
Manidina, Y., Belokon, K., Rumyantsev, V., & Hordyman, O. (2023). APPLICATION OF RADIOACTIVE ISOTOPES IN FIRE DETECTORS. Scientific Journal "Metallurgy", (1), 12-16.

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