L. I. Pavlovskyi, D. V. Gorodetskyi,
V. V. Derenhovskyi, Ye. А. Menshenin
Institute for Safety Problems of Nuclear Power Plants,
NAS of Ukraine, 36a, Kirova st., Chornobyl, 07270, Ukraine
The characteristics of the modern radiation situation in the areas of work under the project “Reconstruction of the Shelter object of the SSE ChNPP in the part of the dismantling of the metal truss of the southern roof reinforcement” are provided. It is shown that during the period of research and industrial operation of the “New Safe Confinement — Shelter object” (NSC-SO) complex, as a result of the sealing of its containment circuit, there was a deterioration of the radiation situation due to an increase in the amount of general and non-fixed surface pollution. The reason for this is the deposition of radioactive aerosols, which are generated both in the Shelter object and during construction work in the internal volume of the NSC-SO complex. According to research data, the average value of the total density of surface pollution by beta-active nuclides of metal structures in the areas of work under the project, for the period from 2018 to 2021, increased by 9.3 times, and the value of unfixed surface pollution by 5.7 times. Such extremely unfavorable radiation conditions encourage the widest possible use of unmanned technologies with the use of remotely controlled robot manipulators (RCRM). In the case of the impossibility of using RCRM for radiation-hazardous technological operations and their replacement by operations performed manually, it is absolutely necessary to forecast the dynamics of air pollution in the working area during the performance of such works in order to guarantee the effective application of appropriate measures for personnel radiation safety. A predictive assessment of radioactive air pollution of work zones in the internal volume of the NSC-SO complex during the execution of project work was provided, which made it possible to optimize measures for the radiation safety of working personnel, in particular, in the selection of appropriate types of means of individual protection of respiratory organs. The proposed approach can be used during the planning of further radiation-hazardous works in the internal volume of the NSC-SO complex, namely, during the dismantling of unstable structures of the Shelter object and the partial removal of nuclear materials and high-level waste from the Shelter object.
Keywords: Chornobyl NPP, southern roof, RCRM, radioactive aerosols, predictive assessment.
1. Research report “Evaluation of changes in the dynamics of evaporation-condensation of moisture in the Shelter object under the NSC, the behavior of FCM under changed conditions and the assessment of changes in dust formation”. Agreement no. 374/17. Chornobyl: ISP NPP, 2017, 108 p. (in Rus.)
2. Reconstruction of the Shelter object of the SSE “ChNPP” in the part of the dismantling of the metal truss of the southern roof reinforcement. Project. Security analysis report. Adjustment. Vol. 6. Chornobyl: SSE “ChNPP”, 2021, 164 p. (in Ukr.)
3. List of zoned premises, buildings, structures and territory of the NSC-SO industrial site. 24PN-S (NBK)]. Chornobyl: SSE “ChNPP”, 2020. (in Ukr.)
4. Research report “Comprehensive assessment of cumulative environmental impacts of radiation-hazardous facilities in the Chornobyl Exclusion Zone”. Chornobyl: SSE “ChNPP”, 2020, 888 p. (in Ukr.)
5. Kalynovskyi O. K., Krasnov V. O., Filippov O. V. (2021). [Radioactive aerosols monitoring of the surface air near the Shelter object within 1998–2019]. Nuclear Power and the Environment, vol. 22, no. 3, pp. 78–83.
6. Project control levels of radiation safety of NSC. Chornobyl: SSE “ChNPP”, 2020. (in Ukr.)
7. Letter from the SSE “ChNPP” no. 1780/23030300–2021 (dated 30.04.2021). (in Ukr.)
8. Reconstruction of the Shelter object of the SSE “ChNPP” in the part of the dismantling of the metal truss of the southern roof reinforcement. Project. Security analysis report 301503.201.006-ЗАБ//ISP NPP NASU. Vol. 6. Chornobyl: SSE “ChNPP”, 2016, 145 p. (in Ukr).
If the article is accepted for publication in the journal «Industrial Heat Engineering» the author must sign an agreement on transfer of copyright. The agreement is sent to the postal (original) or e-mail address (scanned copy) of the journal editions.
Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License International CC-BY that allows others to share the work with an acknowledgement of the work’s authorship and initial publication in this journal.