Authors & Affiliations
Zabrodskaya S.V., Popov E.P., Tykleeva K.V.
A.I. Leypunsky Institute for Physics and Power Engineering, Obninsk, Russia
Zabrodskaya S.V. – Leading Researcher, Dr. Sci. (Phys.-Math.).
Popov E.P. – Senior Researcher.
Tykleeva K.V. – Researcher, A.I. Leypunsky Institute for Physics and Power Engineering. Contacts: 1, pl. Bondarenko, Obninsk, Kaluga region, Russia, 249033. Tel. +7 (484) 399-53-75; e-mail:
Abstract
One of the tasks in the
decommissioning of a fast reactor is the disposal of radioactive sodium. The
cost of sodium disposal depends on its radioactive waste class, which is
determined by the activity of radionuclides, presenting in sodium after the
reactor final shutdown. The main sources of radionuclides affecting on sodium
activity are:
– radionuclides from fuel;
– radionuclides washed off by sodium from the surface of the primary circuit steels;
– radionuclides formed from impurities of sodium itself.
This article presents the research results of the only «impurity» radionuclides influence on
the sodium radioactive waste class of a BN-600 reactor after its final
shutdown. This work considers radionuclides that are formed in sodium as a
result of neutron irradiation of impurities in sodium itself during the reactor
operation.
In the calculations, the maximum values of the impurity content were used from the
regulatory documents. In addition, the decrease in the value of the «impurity»
radionuclides activity in sodium due to the precipitation of radionuclides in
cold traps and on the surfaces of the primary circuit was not taken into
account, therefore the obtained estimates of the «impurity» radionuclides
effect on the class of sodium radioactive waste can be considered conservative.
Analysis of the results of calculating the «impurity» radionuclides activity values and their
class of radioactive waste showed that only eight (Mn-54, Co-60, Zn-65,
Ag-108m, Ag-110m, Sn-121m, Ba-133, Po-210) of all considered «impurity» radionuclides have the activity
within the limits the boundaries of the 4th class of radioactive waste.
The analysis also showed that in the regulatory document of requirements for reactor
purity sodium (OST 95 10582-2003) there are no standards for the content of
some impurities – Mn, Co, Zn, Ag, which, as the results of calculations have
shown, must be taken into account.
Keywords
fast reactor, sodium coolant, impurities, radionuclide, activity, decommissioning, radioactive waste class, TRIGEX, BNAB-93, BN-600
Article Text (PDF, in Russian)
UDC 621.039.7:519.85
Problems of Atomic Science and Technology. Series: Nuclear and Reactor Constants, 2022, issue 1, 1:6