ASME Message

Abstracts
Reinforcement of the ion transport model to cover the lower air speed region is, therefore, very effective. Ions are
generated by an alpha particle in a very thin column with a radius of a few micro-meters and a height of about 0.05 m.
Since the ion density at this temporal stage is very high, the recombination loss, proportional to the square of ion density,
is exclusively dominant within a few milli-seconds after the ion generation. The spatial and temporal scales of this
columnar recombination are too small for CFD simulation. We, therefore, solve an ion transport equation during the
period of columnar recombination with diffusion and recombination terms and incorporated the relation between ion loss
and turbulent parameters of the air flow into CFD. Using this new CFD model, simulations have been done for various
air speeds and targets. Dependence of obtained ion currents on the air speed shows improved accuracy at low air speed.
Those for various shapes and numbers also agree with experiments, showing improvement of simulation accuracy.
5) 40111 – Preparation of Reference Materials on Radiochemical Analysis for Low-Level Radioactive Waste
Generated from Japan Atomic Energy Agency
Ken-ichiro Ishimori, Mikio Nakashima, Kuniaki Takahashi, Yutaka Kameo, JAEA (Japan)
We have advanced the development of simple and rapid determination method for important radionuclides on safety
assessment for disposal of low-level radioactive wastes generated from Japan Atomic Energy Agency (JAEA). In the
radiochemical analyses of the radioactive wastes, it is necessary to manage accuracy and precision of determined values
of radioactivity concentration using reference materials. However, since appropriate reference materials of radioactive
waste are hardly available at the present state, the developments of laboratory-scale preparation methods are required to
supply reference materials. In this work, we investigated preparation methods for the reference materials containing
important nuclides and confirmed the validity of the prepared materials. Additionally a reference material for cemented
liquid waste was also prepared. --Solidified product containing alpha-ray and gamma-ray emitting nuclides--In waste
management in JAEA, non-metallic low-level radioactive solid wastes will be treated by plasma melting at the Advanced
Volume Reduction Facilities (AVRF). In order to clarify optimum melting conditions of solidified products using a
laboratory-scale electric furnace instead of plasma heating device, we conducted melting tests of a miscellaneous
simulated solid waste in the presence of stable isotope tracers. Over 90% of Cs remained in the solidified product by
keeping the basicity (CaO[wt%] / SiO2[wt%]) to be 0.05. Under the optimum melting conditions, we prepared reference
materials containing alpha-ray (237Np, 241Am, and 244Cm) and gamma-ray (60Co, 137Cs, and 152Eu) emitting
nuclides. The characteristics observed in SEM-EDX measurement and chemical durability against acids suggested that
glass structure of the reference materials was almost same as that of solidified products produced by plasma melting.
--Solidified product containing 14C or 36Cl-- Since 14C and 36Cl easily vaporize at a high temperature, it is difficult to
remain the nuclides in solidified product on melting treatment with an electric furnace. First, melting conditions for
solidified glasses containing N or Cl were optimized. We attempted a preparation method which produces 14C or 36Cl in
the solidified glass using nuclear reaction 14N(n, p)14C or 35Cl(n, gamma)36Cl by thermal neutron irradiation.
Reference materials containing 14C or 36Cl were successfully prepared by the proposed method. The radioactivity
concentrations of the reference materials were evaluated from the developed simple and rapid determination method.
From the results, it was confirmed that reference materials, which was useful for routine radiochemical analysis, could be
successfully prepared on the present preparation methods.
SESSION H4: National and International Programs (2)
1) 40213 – U.S. NRC Integrated Spent Fuel Management Plan
Catherine Haney, Shawn Smith, US NRC (USA)
The U.S. Nuclear Regulatory Commission (NRC) is developing an integrated plan for regulating the interrelated
activities that are involved in the management of spent fuel and high-level waste. Treating the system as a whole is
essential for several reasons: (1) decisions made about one component or activity of the waste management system could
significantly affect other components (e.g., a decision made in isolation could inadvertently impact alternatives to the
system as a whole); (2) treating waste management as a system is a more efficient and effective way to determine
priorities, logically complete activities or to appropriately deal with unexpected situations that may arise with
first-of-a-kind programs like reprocessing or alternative waste disposal options; and (3) viewing the system as a whole
avoids gaps and unnecessary duplication in regulations leading to more effective and efficient development and
application of regulatory oversight.
Near-term flexibility is a key consideration because the national policy in the USA appears to be changing and will
likely remain in flux for some time. For example, the Secretary of Energy has convened a commission to conduct a
comprehensive review of the policies for managing the back end of the nuclear fuel cycle. NRC activities will be
informed by this and other relevant developments as it develops its plans. However, integration is essential regardless of
the direction of national policy, as the NRC needs to remain flexible and agile under a range of policy outcomes. This
presentation will describe key aspects of the plan and how the plan will be implemented.
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