ICEM11 Final Program 9.7.11pm_ICEM07 Final Program ... - Events

Abstracts Session 12
nal exposure will be evaluated in next stages of the project). Evaluated scenarios are related to critical groups of professionals constructing
the bridges (workers scenarios). The computer code VISIPLAN 3D ALARA 4.0 planning tool was used for the calculation
of the individual effective dose for professionals. Various limits of the annual individual effective dose are used for the evaluation
of calculation results. The aim of the ongoing modeling is to develop a set of data of maximal radioactivity concentration for
individual radionuclides in the conditionally released steel used in the bridges model constructions in order not to exceed the limits
for the individual effective dose.
4) TREATMENT OF SPENT ACIDIC DECONTAMINANTS WITH A HIGH-EFFICIENCY
CEMENTATION METHOD (wP-59063)
Kou-Ming Lin, Ching-Tu Chang, Ming-Shin Wu, Wen-Chen Lee,
Jen-Chieh Chung, Tsong-Yang Wei, Institute of Nuclear Energy Research (Taiwan)
Metal scrap is a major waste generated from the decommissioning of nuclear facilities. Through a decontamination process,
most of the metal scraps can be cleaned to meet the clearance level, which can then be reused or released according to the regulatory
procedure. Usually, chemical processes will be used in the cleaning step. Phosphoric acid and fluoroboric acid are the typically
used chemicals or decontaminants. Although the regeneration method could be applied to increase the lifetime of the decontaminant,
its decontamination efficiency would decrease after 3 to 5 cycles. In addition, the contaminated nuclide such as Cs-137 is not
easily removed during the regeneration process; it tends to accumulate slowly in the decontaminant. According to the ALARA principle,
decontaminant must be replaced if its activity exceeds the regulatory level. As a result, significant amount of spent strong
acid solution would be generated. The traditional way of treatment is to neutralize the acid solution with an alkaline solution. However,
such method will produce large amount of sludge that requires further stabilization, which offsets the advantages of metal
decontamination.
A high-efficiency solidification method is developed and used to treat the spent phosphoric acid and fluoroboric acid solution
in INER. The self-polymerization nature of
5) METHODOLOGY FOR IDENTIFICATION OF CONDITIONALLY RELEASED MATERIALS FROM
DECOMMISSIONING USING THE OMEGA CODE (wP-59175)
Matej Zachar, Vladimír Daniaka, DECOM, a.s.; Vladimir Necas, Slovak University of Technology (Slovakia)
The nuclear facility decommissioning process is characterized by production of large volume of radioactive materials to be
managed. The materials with radioactivity slightly above the defined unconditional clearance levels could be released conditionally
for a specified industrial application in accordance with beforehand developed scenario ensuring that the limits for radiation
exposure of workers and public will not be exceeded.
The paper presents the methodology for identifying and assessment of the physical and radiological parameters of material
items suitable for using in defined scenarios of conditional reuse of materials resulting from the decommissioning process. The calculation
of mentioned parameters is done by using the analytical code OMEGA with implemented calculation stream for evaluation
the conditional release process.
The necessary input parameters for the OMEGA code are maximum concentrations of each radionuclide in the conditionally
released materials which do not cause the doses above the limit values for the possible scenarios of further use of materials outside
the nuclear site. The examples of such scenarios are assessed and presented in other related papers proposed for the ICEM conference.
Based on the inventory database of physical and radiological characteristics of decommissioned facility, the calculation algorithm
separates the relevant material items with activity concentrations…
6) IMPACT OF NUCLIDE VECTOR COMPOSITION CONTAINED IN CONDITIONALLY
RELEASED STEEL REUSED IN MOTORWAY TUNNELS SCENARIO ON
CALCULATED INDIVIDUAL EFFECTIVE DOSES (wP-59128)
Tomas Hrncir, Vladimir Necas, Slovak University of Technology (Slovakia)
This paper presents ongoing results of the project presented at ICEM 10 [paper 40071] related to the topics of the reuse of conditionally
released materials arising from decommissioning of nuclear installations.
The subject of the presented paper is modelling of motorway tunnels, which reuse the conditionally released steel in form of
reinforcing nets and bars for the concrete construction of tunnels. The general approach for the project was presented at ICEM 10.
The activities of the project continued in evaluating the impact of the nuclide composition contained in the conditionally released
steel on calculated individual effective doses from the external exposure (the internal exposure will be evaluated in next stages of
the project). Mentioned radioactive steel arises during decommissioning and would be reused in motorway tunnels. Evaluated scenarios
are related to critical groups of public (drivers scenarios) and for professionals constructing the tunnels and performing the
maintenance of tunnels (workers scenarios).
The computer code VISIPLAN 4.0 3D ALARA planning tool was used for the calculation of individual effective doses for
worker and for public groups. Various limits of the individual effective dose are used for public and for professionals. The aim of
the ongoing modelling is to develop a set…
7) EVALUATION OF TECHNICAL, ECONOMIC AND FINANCIAL FEASIBILITY FOR RECYCLING
AND REPROCESSING OF RADIOACTIVE WASTE FROM A REMEDIATION WORK OF LOW
AND MEDIUM ACTIVITY FOR THE EXTRACTION OF HEAVY MINERALS (w/oP-59231)
Rodrigo Raposo de Almeida, Federal Fluminense University;
Valter J.G. Mortágua, Industrias Nucleares do Brasil (Brazil)
This paper aims to present the methodology and criteria used for the destination, discard and reuse of waste from the remediation
activities of soil contaminated by radioactive waste of low activity in the USIN Plant. The site is located in São Paulo city,
the city with the largest population of Brazil, with approximately 11 million inhabitants. As the environmental agency in São Paulo
state, in this neighborhood there are several cases of severe contamination of soil and groundwater. The situation of contamination
is so severe that it is forbidden the use of groundwater in the region for an indefinite period. Site of the plant running in a monazite
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