Development of scaling factors for the activated concrete of the KRR-2.
The biological shielding concrete of KRR-2 was activated by a thermal neutron reaction during the operation of the reactor, thus a variety of radionuclides were generated in the concrete. In order to verify the radioactivity for the final disposal of waste and to achieve a more efficient cutting of the concrete, the radioactivity inventories and distributions of the activated concrete were evaluated. The activity of gamma-emitting radionuclides was measured by using an HPGe detector. The beta-emitting radionuclides were measured by an oxidation/combustion method for (3)H and (14)C and a combined method of an extraction chromatography and a liquid scintillation for (55)Fe and (63)Ni. The dominant radioactive nuclides in the activated concrete were (3)H, (14)C, (55)Fe and (60)Co, and the maximum gamma activity was 105Bq/g at the surface around the thermal column. The specific activities of all the nuclides were found to decrease almost linearly on a logarithmic scale along the depth from the inner surface of the concrete. Equations for scaling factors were obtained by a linear regression of logarithms from the radioactivity data of (3)H/(60)Co, (14)C/(60)Co and (55)Fe/(60)Co nuclide pairs of the activated concrete. The scaling factors can be utilized for the estimation of beta radioactivity without the time consuming separation processes of the nuclides.
Hong
Sang-Bum
SB
Decommissioning Technology Development Division, Korea Atomic Energy Research Institute, 150-1 Deokjin-dong, Yuseong-gu, Daejeon 305-353, Republic of Korea. sbhong@kaeri.re.kr
Kang
Mun-Ja
MJ
Lee
Ki-Won
KW
Chung
Un-Soo
US
D002250:Carbon Radioisotopes / Q000032:analysis; D003037:Cobalt Radioisotopes / Q000032:analysis; D003252:Construction Materials / Q000032:analysis*; D007504:Iron Radioisotopes / Q000032:analysis; D009688:Nuclear Reactors; D011848:Radioactive Pollutants / Q000032:analysis*; D011868:Radioisotopes / Q000032:analysis*; D014316:Tritium / Q000032:analysis
D002250:Carbon Radioisotopes; D003037:Cobalt Radioisotopes; D007504:Iron Radioisotopes; D011848:Radioactive Pollutants; D011868:Radioisotopes; D014316:Tritium