Survey of Estimation Methods for Radioactive Inventory in Nuclear Reactors to be Decommissioned
In the nuclear reactors to be decommissioned, radioactive inventories due to neutron activation are calculated using application codes and cross section libraries. Some of them are evaluated through benchmark tests. This review surveys the present situation and problems of the calculation methods together with the measurements on radioactive inventories and chemical composition analyses of reactor components.<BR>The ANISN and DOT calculations are almost carried out from 100 to 30 and from 26 to 5 neutron energy groups, respectively for the activation calculation, which is widely implemented using ORIGEN and other codes for activation calculation. The calculation models and the physical quantities for the calculation are employed variously and neutron spectrum does not always correspond properly between the codes. A lot of neutron streams from penetrating holes in the biological shielding concrete (BSC) build up neutron fluxes in the BSC, and a difference between the calculations and measurements of radioactive inventories tends to grow with distance into the BSC. These factors at least require a three-dimensional calculation and measurements in order to enhance and confirm calculation accuracy.
- Journal of nuclear science and technology
Journal of nuclear science and technology 35(5), 379-391, 1998-05-25
Atomic Energy Society of Japan