Development of a Process for Co-Conversion of Pu-U Nitrate Mixed Solutions to Mixed Oxide Powder Using Microwave Heating Method

• Published in: Journal of nuclear science and technology Vol. 20; no. 7; pp. 529 - 536
• Main Authors: KOIZUMI, Masumichi, OHTSUKA, Katsuyuki, OHSHIMA, Hirofumi, ISAGAWA, Hiroto, AKIYAMA, Hideo, TODOKORO, Akio, NARUKI, Kaoru
• Format: Journal Article
• Language: English
• Published: Tokyo Taylor & Francis Group 01.07.1983; Atomic Energy Society of Japan; Taylor & Francis Ltd
• Subjects: Applied sciences; calcination; co-conversion; denitration; Energy; Exact sciences and technology; Fuels; homogeneity; microwave heating; mixed oxide powder; mixture; non-proliferation policy; nuclear fuel cycle; Nuclear fuels; plutonium conversion facility; plutonium nitrates; powder characteristics; Preparation and processing of nuclear fuels; process; uranium nitrates; Plutonium IV Uranium IV Oxides Mixed; Japan; Preparation; Development; Nuclear fuel; Nitrates; Microwave heating; Operating process; Conversion; Comparative study; Powder
• ISSN: 0022-3131; 1881-1248
• DOI: 10.1080/18811248.1983.9733431

For the complete nuclear fuel cycle, the development of a process for the co-conversion of Pu-U nitrate mixed solutions to mixed oxide powder has been performed along the line of non-proliferation policy of nuclear materials. A new co-conversion process using a microwave heating method has been developed and successfully demonstrated with good results using the test unit with a capacity of 2 kg MOX/d. Through the experiments and engineering test operations, several important data have been obtained concerning the feasibility of the test unit, powder characteristics and homogeneity of the product, and impurity pickups during denitration process. The results of these experimental operations show that the co-conversion process using a microwave heating method has many excellent advantages, such as good powder characteristics of the product, good homogeneity of Pu-U oxide, simplicity of the process, minimum liquid waste, no possibility of changing the Pu/U ratio and stable operability of the plant. Since August 1979, plutonium nitrate solution transported from the Tokai Reprocessing Plant has been converted to mixed oxide powder which has the Pu/U ratio = 1. The products have been processed to the ATR "FUGEN" reloading fuel. Based on the successful development of the co-conversion process, the microwave heating direct denitration facility with a 10 kg MOX/d capacity has been constructed adjacent to the reprocessing plant. This facility will come into hot operation by the fall of this year. For future development of the microwave heating method, a continuous direct denitration, a vitrification of high active liquid waste and a solidification of the plutonium-contaminated waste are investigated in Power Reactor and Nuclear Fuel Development Corp.