UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS

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2022-08-12 15:39

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Conference: Bucharest University Faculty of Physics 2016 Meeting


Section: Nuclear and Elementary Particles Physics


Title:
The analysis of radiological risk for workers involved in the transfer of radioactive liquid wastes arising from decommissioning process of a nuclear reactor


Authors:
C. TUC, A. STOICHIOIU, R. DEJU, F. MIHAI


Affiliation:
Horia Hulubei National Institute for Physics and Nuclear Engineering, P.O.B. MG-6, RO-077125 Magurele, Romania


E-mail
tuca@nipne.ro


Keywords:
radiological risk; activity concentration; equivalent effective dose; nuclear reactor decommissioning


Abstract:
The paper aims to analyze the radiological risk of workers involved in radioactive liquid waste transfer operations (for normal and abnormal circumstances) resulted from the decommissioning process of VVR-S nuclear reactor. The radioactive liquids results from the emptying of the underground buffer tank (source 1) and nuclear spent fuel storage ponds (source 2). The personal equivalent dose Hp(10) received by a worker who performs the transfer operation of the container with liquid waste from ponds to the treatment plant in normal working conditions is calculated based on the activity concentrations measured for liquid effluents and specific dose coefficients. For transfer process of liquid wastes (70 operations) the integral dose is 61.3 Sv (14.3 Sv from source 1 and 47 Sv from source 2). In parallel dose ambient equivalent H*(10) measurements for source 2 are performed using an environment thermo-luminescent system. The dose is 3.8 Sv and it can be concludes that the operational values are in good agreement with those calculated considering that quantities as being equivalent. The abnormal scenario consists in upside down of the container during the transport and the spreading of liquid on the concrete surface. During the clean-up operation the worker contamination could occur, thus beta dose rates are calculated. The highest values of the dose rate are obtained for the accidental discharges of liquid from the pond - 0.70 Sv/h - and underground buffer tank - 0.16 Sv/h - due to the concentration of activity 3.21E+08 Bq and 7.29E+07 respectively.


References:

[1] Tuca C, Stochioiu A, Sahagia M, Gurau D, Dragusin M 2015 Assessment of derived emission limits for radioactive effluents resulted from the decommissioning activities of the VVR-S nuclear research reactor, J. Environ. Rad. 148, 130-136

[2] Tuca C, Stochioiu A, Gurau D, 2016 Analysis of radionuclides inventory contained in liquid effluents resulted from decommissioning of VVR-S nuclear research reactor Rom. Rep. Phys. in press

[3] Martin JE 2008 Physics for Radiation Protection, a Handbook, second Edition, Completely Revised and Enlarged, Ed. Wiley-WCH VerlagGmbh&Co. KGaA, Weinheim, ISBN 3-527-40611-5

[4] ICRP 2010 Conversion Coefficients for Radiological Protection Quantities for External Radiation Exposures. ICRP Publication 116 (Elsevier: ICRP) Ann. ICRP 40(2V5)

[5] CNCAN 2002 Personal Dosimetry Norms, (NSR-06), Approved through the no. 180/05.09.2002 CNCAN President Order, published in the 769 bis Official Bulletin (part I)

[6] CNCAN 2000 Fundamentals Norms for Radiological Safety, NSR-01, Approved through the 14/24.01.2000 CNCAN President Order, published in the 404/29.08.2000 Official Bulletin (part I). Table 4 C1



Acknowledgement:
The authors offer many thanks to Dr. M. Sahagia for her suggestion and feedback when clarifications of issues were required.