[en] A total of 36 tons of slightly enriched uranium metal in the form of Mark VR, VE, and 15 slugs and cores is to be returned to NLO from Building 777-M. The most practical method of shipping this uranium is in the NLO wooden containers in which it was originally received. However, existing shipping regulations were written after this uranium was shipped and the Certificate of Compliance, COC, does not authorize the shipment of this uranium in these boxes and the Safety Analysis Report for Packaging, SARP, does not discuss this uranium. Therefore, this supplement to the SARP is intended to provide the basis for revision of the COC to permit shipping Mark VR, VE and 15 cores and slugs in NLO wooden containers

[en] Revisions have been made to the material control and accounting requirements for NRC licensees authorized to possess and use more than one effective kilogram of special nuclear material of low strategic significance to have material control and accounting systems able to (1) confirm the presence of special nuclear material, (2) resolve indications of missing material, and (3) aid in the investigation and recovery of missing material. This document presents criteria that can be used to aid in judging the acceptability of licensee plans that would be submitted to the NRC for implementing these capabilities. General performance objectives, system capabilities, and recordkeeping are addressed

[en] The Safeguards Committee of the Institute of Nuclear Materials Management assessed the domestic safeguards for low-enriched uranium, by evaluating the threats of maleficent use of low-enriched uranium, performing a comparative risk analysis, and applying safeguards program elements to increase where control was deemed appropriate. It was concluded that current regulations do not appropriately address the control of low-enriched uranium based on relative risks to the public, and recommendations were made for changes in the regulation

[en] Revisions have been made to the material control and accounting requirements for NRC licensees authorized to possess and use more than one effective kilogram of special nuclear material of low strategic significance to have MC and A systems able to (1) confirm the presence of special nuclear material, (2) resolve indications of missing material, and (3) aid in the investigation and recovery of missing material. This document presents criteria that can be used to aid in judging the acceptability of licensee plans that would be submitted to the NRC for implementing these capabilities. General performance objectives, system capabilities, and recordkeeping are addressed

No abstract available

[en] Improvements in the efficiency and effectiveness of inventory-change verification are necessary at certain nuclear facilities, of which one example is low-enriched uranium fuel fabrication facilities. The Safeguards Criteria suggested carrying out interim inventory-change verifications with randomized inspections. This paper describes randomized inspection schemes for inventory change verifications and evaluates the achievable detection probabilities for realistic plant receipt and shipment schedules and stratum residence times as a. function of the inspection frequency and effort and compares these with the existing inspection strategies

No abstract available

[en] Ten benchmark experiments were performed at the Critical Mass Laboratory at Rockwell International's Rocky Flats Plant, Golden, Colorado, for the US Nuclear Regulatory Commission. They provide accurate criticality data for low-enriched damp uranium oxide (U₃O₈) systems. The core studied consisted of 152 mm cubical aluminum cans containing an average of 15,129 g of low-enriched (4.46% ²³⁵U) uranium oxide compacted to a density of 4.68 g/cm³ and with an H/U atomic ratio of 0.77. One hundred twenty five (125) of these cans were arranged in an approx. 770 mm cubical array. Since the oxide alone cannot be made critical in an array of this size, an enriched (approx. 93% ²³⁵U) metal or solution driver was used to achieve criticality. Measurements are reported for systems having the least practical reflection and for systems reflected by approx. 254-mm-thick concrete or plastic. Under the three reflection conditions, the mass of the uranium metal driver ranged from 29.87 kg to 33.54 kg for an oxide core of 1864.6 kg. For an oxide core of 1824.9 kg, the weight of the high concentration (351.2 kg U/m³) solution driver varied from 14.07 kg to 16.14 kg, and the weight of the low concentration (86.4 kg U/m³) solution driver from 12.4 kg to 14.0 kg

[en] The paper goal is to find out the burnup influence on lattice parameters of interest when nuclear fuels with Natural Uranium (NU) and Slightly Enriched Uranium (SEU) are used. The considered lattice parameters consist of the infinite multiplication factor and the isotopic contribution to the fission power for some of the major actinides such as Uranium and Plutonium. The widely spread transport equation solver computer code WIMS (Winfrith Improved Multigroup Scheme) was used. The working configurations correspond both to fresh and to irradiated nuclear fuel up to the discharge burnup from a generic CANDU power reactor. Three Uranium enrichments were used: 0.72 w% ''2''3''5U (corresponding to the Natural Uranium), 1%w ''2''3''5U and 2%w ''2''3''5U corresponding to the SEU fuel. The unique critical (discharge) burnup values are also presented for every of the three enrichments. The results showed that almost one and a half discharge burnup can be obtained using a nuclear fuel with a quite light enrichment of 1%w ''2''3''5U, while 2% ''2''3''5U configuration is able to supply almost three times larger discharge burnup. The peculiar individual fissile actinides' contributions to the total fission power with respect to enrichments and burnups are also discussed. (authors)

No abstract available