| Abstract: | Characterization of crud on surfaces of the channel box in JPDR has been carried out by means of chemical, radiochemical, X-ray diffraction and infrared spectrum analyses. The main cations in the crud are Fe and Ni: The sum of their weights amounts to more than 90% of the total weight of the cations found. The results of X-ray diffraction and infrared spectrum analyses revealed that the crud consisted of Ni0.65Fe2.35O4, NiO and γ-FeOOH. Based on the neutron flux calculated from the burn-up of 235U and 238U in the spent fuel, the apparent residence time of elements on the surface of the channel box was calculated to be 230 d for Co, 260 d for Ni and 70 d for Fe. The value for Fe should be taken as a minimum value, because of the presence of γ-FeOOH in the crud, which has been formed during the storage in a pond. The present data are discussed in correlation with the one in the reactor water. |
