Radioactive Fission Waste from Molybdenum-99 Production and Proliferation Risks

Abstract

Molybdenum-99 (99Mo) is a parent radioisotope of Technetium-99m (99mTc) widely used in nuclear diagnostics. The production of this radioisotope by PT. INUKI generated radioactive fission waste (RFW) that theoretically contains239Pu and235U, posing a nuclear proliferation risk. This paper discusses the determination of radionuclides inventory in the RFW and the proposed strategy for its management. The radionuclides inventory in the RFW was calculated using ORIGEN 2.1 code. The input parameters were obtained from one batch of 99Mo production using high enriched uranium in PT. INUKI. The result showed that the RFW contained activation products, actinides, and fission products, including239Pu and235U. This result was then used for consideration of the management of the RFW. The concentration of 235U was reduced by a down-blending method. The proposed strategy to further manage the down-blended RFW was converting it to U3O8 solid form, placed in a canister, and eventually stored in the interim storage for high-level waste located in The Radioactive Waste Technology Center.

Radioactive Fission Waste of The Conversion of High-Enriched Uranium to Low-Enriched Uranium Target on 99Mo Production

“…This 99 Mo production is under the CINTICHEM USA license, which uses high-enrichment uranium (HEU) targets. However, to prevent the misuse of HEU for nuclear weapons, the International Atomic Energy Agency (IAEA) has strictly limited the use of HEU, either for research reactor nuclear fuel or raw material of 99 Mo production [5,7,8]. Therefore, at the end of 2010, the use of HEU 92.7% for 99 Mo production was converted to low enriched uranium (LEU) 19.84%.…”

“…Furthermore, the production requires a larger amount of uranium target in order to obtain the same amount of 99 Mo radioisotope [5,10]. Both remaining non-fission 235 U and 239 Pu are fissile material that is concerned to be misused as nuclear weapons, therefore, 235 U and 239 Pu require strict supervision [7,11]. On the other hand, the RFW also contains several radioisotopes, such as 90 Sr, 137 Cs, and 131 I, which can be used in the medical for the therapy or diagnosis of human organ abnormalities [12,13].…”

“…Another method studied is the precipitation and calcination of the liquid RFW to the U3O8 solid phase by a researcher from the USA [18]. Regarding the production of 99 Mo in Indonesia, several topics, such as the characteristics of waste from 99 Mo production using the HEU target [9], RFW from 99 Mo production, and proliferation risks that also describe waste from the HEU target [7], have been studied. However, the research on the waste from the LEU target for Indonesia's 99 Mo production has not been carried out.…”

Simulation of neutron shielding performance of Al-Cd alloy for radioactive waste container

“…The reactor has been operating since 1987 and generating radioactive waste including the MTR plate spent nuclear fuel [1]. The spent fuels still contain high decay heat, gamma and neutron radiation [2]. After being discharged from the reactor core, the spent nuclear fuels are stored in the reactor pool at least for 100 days to allow its decay heat and radiation level decrease.…”

“…However, the study for alloy containing Cd for neutron shielding is limited [14]. Beside for the spent fuel, this alloy can also be used for other radioactive waste emitting neutron radiation, such as disused sealed radioactive sources and radioactive uranium waste from radioisotope production [15].The neutron shielding evaluation was carried out by simulation using MCNP5 code. The MCNP program is widely used to solve various nuclear installation problems, such as criticality, shielding, gamma, neutron, and photon emission analyses.…”