Regional cooperation in RWM in the AO countries.

Regional cooperation in radioactive waste management (RWM) in the Asian and Oceanic countries has been successfully developing for more than 20 y. At present, the Asian and Oceanic countries recognise that there are several projects under the regional cooperation, such as the Forum for Nuclear Cooperation in Asia (FNCA), the Asian Nuclear Safety Network (ANSN) and the International Atomic Energy Agency (IAEA) regional projects. The FNCA on Radiation Safety and RWM is an effective mechanism for enhancing socio-economic development through active regional partnership in the peaceful and safe utilisation of nuclear technology. The ANSN Topical Group on RWM is established for exchanging, pooling, and sharing knowledge in the field of nuclear safety. For IAEA regional cooperation on RWM, such as IAEA-regional project RAS/3/009 Strengthening Infrastructure of RWM can provide and support Asian and Oceanic countries for national work plan, fellowships and scientific visits as well as expert services.

Radiological accident and incident in Thailand: lesson to be learned.

Radioactive materials in Thailand have been used in medicine, research and industry for more than 50 y. Several radiological accident and incidents happened in the past 10 y. A serious one was the radiological accident that occurred in Samut Prakan, Thailand in 2000. The serious radiological accident occurred when the (60)Co head was partially dismantled, taken from that storage to sell as scrap metal. Three victims died and 10 people received high dose from the source. The lesson learned from the radiological accident in Samut Prakan was to improve in many subjects, such as efficiency in Ministerial Regulations and Atomic Energy Act, emergency response and etc. In addition to the serious accident, there are also some small incidents that occurred, such as detection of contaminated scrap metals from the re-cycling of scrap metals from steel factories. Therefore, the radiation protection infrastructure was established after the accident. Laws and regulations of radiation safety and the relevant regulatory procedures must be revised.

Study on migration behaviour of 237Np and 241Am in near-surface environments.

Laboratory-scale experiments were performed to investigate migration behaviour of (237)Np and (241)Am, which were deposited onto the ground surface from spent fuel reprocessing facilities. Migration experiments by column method were conducted for a sandy soil and a reddish soil by varying the volume of eluting solution. There seemed to be two chemical species of (237)Np in the sandy soil column: one is cationic and the other is particulate form. The particulates moved without significant interaction with the sandy soil. The sorption of cationic (237)Np was controlled by both a reversible ion-exchange reaction and irreversible reactions. Most of (241)Am was formed into rather large particulates and trapped in the sandy soil column. The (237)Np and (241)Am loaded into the reddish soil column moved deeper with increasing eluting volume. The sorption was mainly controlled by ion-exchange reaction. The migration behaviour might be evaluated by the distribution coefficient.