[en] Chalk River Laboratories (CRL) has a mandate from the Canadian government to develop nuclear technologies that support generation of clean, safe energy. This includes the development of advanced nuclear fuel technologies to ensure sustainable energy sources for Canadians. The Fuel Development Branch leads CRL's development of advanced nuclear-reactor fuels. CRL capabilities include fuel fabrication development, irradiation testing, post-irradiation examination (PIE), materials characterization and code development (modeling). This presentation provides an overview of these capabilities and describes recent development activities that support fuel-cycle flexibility in heavy-water reactors. This includes a review of irradiation testing and PIE for mixed-oxide, thoria, high-burnup UO2 and low-void reactivity fuels and burnable neutron absorbers. Fabrication development, material characterizations and modeling associated with these tests are also described.

[en] This is a presentation about post-irradiation fuel examination (PIE). The paper discusses the PIE facilities that exist, the reasons for examining fuel in hot cells, the method by which the fuel is examined, what is observed and measured and what the data means

[en] We describe a rapid, sensitive, and precise radioimmunoassay for urinary albumin (U/sub alb/). Aliquots of diluted urine were incubated at room temperature for 1 h with ¹²⁵I-labelled albumin and a rabbit antiserum monospecifid for human albumin. Phase separation was effected by the double-antibody technique. The dose-response curve was linear in the range of 15.6 to 10,000 ng, equivalent to 4 to 3000 mg/liter of urine. The limit of sensitivity was 16 ng of albumin. The coefficient of assay variation was 4.8%, both at 44 mg/liter and at 1304 mg/liter. A displacement curve obtained with a serially diluted urine sample of high albumin concentration was completely superimposable with the curve for which human albumin was used as a standard. In 26 normal individuals the range for U/sub alb/ was 2.2 to 12.6 mg/24 h, and for albumin clearance (C/sub alb/), 1.8 x 10^-5--19.6 x 10^-5 ml/min. After renal homografts in 25 patients, U/sub alb/ ranged from 16.9 to 9928 mg/24 h, and C/sub alb/ from 2.7 x 10^-4 to 1.7 x 10^-1 ml/min. Both increased U/sub alb/ and C/sub alb/ correlated well with the severity of renal homograft rejection

[en] We describe a radioimmunoassay for beta 2-microglobulin (beta 2 mu) in serum and urine. We incubated aliquots of diluted samples at room temperature for 1 h with ¹²⁵I-labeled beta 2 mu and a rabbit antiserum monospecific for human beta 2 mu, and separated the phases by the double-antibody technique. The logit-log transformed dose-response curve was linear in the range 2 to 64 ng, equivalent to 0.5 to 16 mg/L of serum and 0.5 to 320 mg/L of urine. Assay sensitivity was 2.4 ng of beta 2 mu. Validation studies included tests of precision, accuracy, antibody specificity, and parallelism of the dose-response curves for standard and unknown. In a study of 25 normal individuals, serum and urine beta 2 mu ranged from 1.1 to 2.3 mg/L and 40 to 360 micrograms/24 h; the clearance of beta 2 mu was 8 to 130 microL/min. In 21 renal allograft recipients tested one to five weeks after transplantation, serum and urine beta 2 mu ranged from 3.9 to 15.6 mg/L and 7.2 to 611 mg/24 h; beta 2 mu clearance was 0.60 to 33.3 mL/min. Values for both serum and urine correlated well with severity of allograft rejection

[en] Radionuclide studies in a renal-transplant patient with congestive heart failure suggested vascular steal from the renal allograft by a contralateral femoral arteriovenous fistula. These reliable, noninvasive diagnostic procedures have potential use in similar settings to evaluate allograft perfusion and function. Correction by removal of the fistula was demonstrated

[en] Thorium is anticipated to play a potentially significant role in the world's future energy supply as the international nuclear power industry moves towards the implementation of more sustainable nuclear technologies and advanced fuel cycles. Canadian Nuclear Laboratories (CNL), formerly Atomic Energy of Canada Limited, has been investigating thorium-fuelled reactor concepts and developing thoria (thorium dioxide) fuel technology for more than 55 years, complimenting international experience in the development of thorium-based fuel cycles. Although there is a strong foundation based on past experience, gaps exist in the science and technology (S&T) required to implement the use of thorium-based fuels on an industrial scale. In this paper, progress in thoria fuel S&T is reviewed and research and development needs for the deployment of thorium-based fuel cycles (with the focus on the use of thoria, ThO₂) are identified from a Canadian perspective. CNL plans to address known S&T gaps are also discussed. (author)

[en] The NRU (National Research Universal) Reactor has operated at Atomic Energy of Canada's (AECL's) Chalk River Laboratories since 1957. NRU is a 135 MWt multipurpose heavy water-cooled and moderated research reactor that provides a neutron source for a wide range of applications. This paper reviews NRU reactor's current capabilities and highlights of past experience, from the perspectives of materials research with neutron beams, isotope production and irradiation of nuclear fuels, materials and components. One of NRU's primary mandates in recent times has been the production of Molybenum-99, which is needed for the majority of imaging procedures in nuclear medicine worldwide. Per previously announced Government of Canada policy, it is expected that NRU will cease supplying Molybdenum-99 beyond 2016, constituting a major change in the mandate and operation of the reactor. The operation of NRU beyond 2016 is being considered to support industry-led, cost-shared nuclear innovation in Canada. This marks a new era for NRU, where business-driven needs and partnerships shape the way this powerful and versatile resource for science and technology delivers benefits to Canada and the world. (author)

[en] The METHUSELAH II code has been used to predict long term reactivity and isotopic changes in the YANKEE, Dresden and NRX reactors. In general it is shown that there is a satisfactory measure of agreement and the first core lives of YANKEE and Dresden appear well predicted. However there are discrepancies in the isotopic composition of the plutonium formed which appear to be correlated with the degree of hardness of the reactor spectrum. It is demonstrated that plausible changes in nuclear data could reduce the discrepancies. (author)

[en] The echo produced when a light 'pulse' from a stellar source (e.g. a nova or supernova) is reflected by circumstellar or interstellar material can appear as a luminous ring expanding at a rate that can be superluminal, i.e. having an apparent motion within the source, transverse to the observer's line of sight, at a speed greater than that of light. 'Light-echo optics' applied to the star RS Puppis and its nebula suggests that when nebular features in peripheral regions of circumstellar-shell images are observed, superluminal effects are not evident; however, such observations can give the stellar distance from the observer. Light-echo optics for an interstellar plane sheet, inclined to the observer's line of sight, can be applied to Nova GK Persei 1901 and SN 1987A, which show superluminal effects. For SN 1987A, an intense thermal x-ray source should be produced in AD 2003, when the advancing supernova ejecta interact with a circumstellar ring, 250 light days in radius: the arc-shaped x-ray image, while not actually a 'radiation echo', should expand at a superluminal rate for about 75 days from the time of its first appearance, and also for the same time before the completion of its 'circuit' around the ring

[en] Highlights: • MOX performance in experimental irradiations at CNL was very similar to that of UO₂. • Fission gas release in MOX fuel shows a strong dependence on maximum powers achieved. • Fission gas release in MOX fuel shows a weaker (secondary) dependence on burnup. • Fission gas release increases in MOX when the power exceeds 55 kW/m, regardless of burnup. • Sheath strains in MOX occur at the low end of the range of UO₂ sheath strains. • Fission-gas release, grain growth and oxide thickness on sheath appear to be related to the homogeneity of the MOX fuel.