[en] In the current design of the fine motion control rod drive (FMCRD) in boiling water reactors, nearly 30 guide rollers made of Stellite No.3 are going to be used in each FMCRD. The release of cobalt from these guide rollers into the reactor core is inevitable, which will raise ⁶⁰Co levels in reactor water and will increase radiation exposure during maintenance work. The purpose of this work is to develop cobalt-free guide rollers that have the necessary properties required for FMCRD guide rollers and replace the current guide rollers. This research and development (R ampersand D) project has been performed under the sponsorship of the Advanced Nuclear Equipment Research Institute, which established the research contract with the Agency of National Resources and Energy, Ministry of International Trade and Industry

[en] Since 1989, an international collaboration group, with support from the European Commission and from numerous national grant agencies, has been working to establish boron neutron capture therapy (BNCT) with epithermal neutrons as an alternative therapy for high-grade glioma. A total of 15 European countries are working toward this goal

[en] In the past 3 yr, two projects have been completed that involved transporting large, internally contaminated reactor components to the disposal site in Barnwell, South Carolina. A variety of transport modes were used, including barge, rail, and heavy-haul trailers. This paper summarizes the two projects and enumerates the lessons learned from them

[en] Tritium contamination of stainless steel poses radiological problems at facilities that produce or process tritium on a large scale. Decommissioning tasks at these facilities are complicated by the potential of increased radiation dose to personnel either by direct skin contact with the tritiated surfaces or by inhalation of tritium gases released from the contaminated materials. A study of the migration of tritium in type 304 stainless steel was undertaken. One of the tritium impregnation methods utilized was recoil injection

[en] Improvements in power plant operations and maintenance have seen made possible through the use of improved software systems and communications capabilities provided by distributed computer systems and networks. Staff functions have been added at several operating units to improve performance. A new class of software system is also in use at South Texas Project and DC Cook. These staff activities are performed using the new software tool support and associated improvements in operations that have been produced

[en] The major factor in determining the extent Of 12 in solution is pH. In containment where no pH-control chemicals are present, the acidity or basicity of the water pool will be determined by materials that are introduced into containment as a result of the accident itself. These materials may be fission products (i.e., cesium compounds), thermally produced products (i.e., core-concrete aerosols), or compounds produced by radiation (i.e., nitric acid). in situations where pH levels fall below ∼7, the formation of I₂ will occur in irradiated iodide solutions. A correlation between pH and iodine formation is needed so that the amounts of I₂ in water pools can be assessed. This, in turn, determines the amount of I₂ in the atmosphere available for escape by containment leakage. A number of calculational routines based on more than 100 differential equations representing individual reactions can be found in the literature. In this work, it is shown that a simpler approach based on the steadystate decomposition of hydrogen peroxide should correctly describe iodine formation in severe accidents. Comparisons with test data show this approach to be valid

[en] The purpose of the work discussed in this paper was to produce a computer code to perform licensing-based off-site and on-site dose calculations for the Chapter 15 Accident Analysis in a safety analysis report. This paper describes the TRACI code and compares its results to analytical solutions and to a previously verified vendor code (Code A), which it replaces

[en] Many applications of accelerator beams require target irradiation that is uniform (within some specification) for an area extending laterally with respect to the incident beam axis. The accelerator production of tritium (APT) project, for example, requires that the spallation-induced lithium conversion (SILC) target have a reasonably uniform deposition of beam power over a 1.4- x 1.4-m area, although the Gaussian intensity-profile beam exiting from the APT linac has a full-width at half-maximum of only millimetres. Until recently, the only techniques for uniformly illuminating a laterally extended target were interposition of a thick absorber before the target or repetitive sweeping of the beam (open-quotes rasteringclose quotes). Each is seriously flawed, the first in being wasteful of beam and of accelerator power and creating radioactivity, the second in the deflection magnet power required, that time-dependent phenomena may require simultaneous irradiation of the whole target, and a raster system failure could allow focused beam to impact the target

[en] The RADionuclide Transport, Removal, And Dose (RAD-TRAD) code is designed for U.S. Nuclear Regulatory Commission (USNRC) use to calculate the radiological consequences to the off-site population and to control room operators following a design-basis accident at light water reactor (LWR) power plants. This code utilizes updated reactor accident source terms published in draft NUREG-1465. The code will track the transport of radionuclides as they are released from the reactor pressure vessel, travel through the primary containment and other buildings, and are released to the environment. As the radioactive material is transported through the primary containment and other buildings, credit for several removal mechanisms may be taken, including sprays, suppression pools, overlying pools, filters, and natural deposition. Simple models are available for these different removal mechanisms that use, as input, information about the conditions in the plant and predict either a removal coefficient λ or decontamination factor. The user may elect to use these models or input a single value for a removal coefficient or decontamination factor

[en] As part of the level II probabilistic risk assessment (PRA) performed for the GE Simplified Boiling Water Reactor (SBWR) an analysis was performed to assess the probability that the debris released from the reactor vessel was in a coolable configuration in the lower drywell and, if not, to assess the type of core/concrete attack that would occur. The coolability of the debris ex-vessel was explicitly evaluated by an event in the SBWR containment event tree (CET). A detailed decomposition event tree (DET) was developed to aid in the quantification of this CET event. The headings in the DET were selected to represent plant physical states (e.g., reactor vessel pressure at the time of vessel failure) and the uncertainties associated with the occurrence of critical physical phenomena (e.g., debris configuration in the lower drywell) considered important to assessing whether the debris was coolable or not coolable ex-vessel