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Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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Deep Space: The new frontier of radiation controls
In commercial nuclear power, there has always been a deliberate tension between the regulator and the utility owner. The regulator fundamentally exists to protect the worker, and the utility, to make a profit. It is a win-win balance.
From the U.S. nuclear industry has emerged a brilliantly successful occupational nuclear safety record—largely the result of an ALARA (as low as reasonably achievable) process that has driven exposure rates down to what only a decade ago would have been considered unthinkable. In the U.S. nuclear industry, the system has accomplished an excellent, nearly seamless process that succeeds to the benefit of both employee and utility owner.
Masaumi Nakahara, Tsutomu Koizumi, Kazunori Nomura
Nuclear Technology | Volume 174 | Number 1 | April 2011 | Pages 77-84
Technical Paper | Chemical Reprocessing | doi.org/10.13182/NT11-A11681
Articles are hosted by Taylor and Francis Online.
A crystal purification process consisting of sweating and melt filtration was developed to improve decontamination factors (DFs) of fission product impurities from uranyl nitrate hexahydrate (UNH) crystal recovered from a dissolver solution of irradiated fast reactor core fuel. Batch experiments on the sweating and melt filtration processes were carried out at 56 to 80°C. Although the DFs of solid impurities such as Cs and Ba remain the same in the sweating process, those of liquid impurities such as Zr, Nb, Ru, Ce, and Eu were 2.32, 2.40, 2.50, 2.45, and 2.60 at 60°C. On the other hand, the DF of Pu for the UNH crystal slightly increased to 1.25 at 60°C. Because Pu incorporated the UNH crystal in both the solid impurities such as Cs2Pu(NO3)6 and in the liquid impurities, Pu in the liquid fraction was removed by the sweating operation. Decontamination of liquid impurities was effective with sweating time and with a rise in sweating temperature. In the melt filtration process, 0.45- to 5.0-m-diam filters were used for the separation of the molten UNH crystal. The DF of Ba was approximately ten times as high as the crude crystal with 0.45- to 5.0-m-diam filters. The particle size of Pu and Cs formed as Cs2Pu(NO3)6 was quite small. As a proof of this, although the decontamination of Pu and Cs was not effective with a 5.0-m-diam filter, their DFs rose 2.7 times using a 0.45-m-diam filter.
