[en] One of six Generation-IV reactor technologies being studied is the use of supercritical water as a coolant. The advantages of using supercritical water include improved thermal efficiency, plant simplifications, and the ability to utilize existing turbine technologies. A model of the CANDU geometry lattice cell with supercritical water coolant using the code WIMS is examined. The model is a 43-pin fuel bundle with centre absorbing pin containing dysprosium oxide. This is compared to a WIMS model of a standard 37 element CANDU-6 bundle with supercritical water coolant. Studied are the effects of coolant density and dysprosium on reactivity based transients. (author)

[en] The purpose of the experiments described is to evaluate the relative biological effectiveness (RBE) of high energy charged particles for cell killing in the mouse crypt-cell survival assay. The reference radiation, 225 kVp x rays, is slightly more effective than plateau helium ions. For carbon, neon and argon ions there is a suggestion of a saturation effect with increasing LET. Furthermore, it should be emphasized that there is a large difference associated with particles of different atomic number or mass at the same average LET

[en] The TRIUMF dc optically-pumped polarized H^- ion source (OPPIS) produces 200 microA dc H^- current at 85% polarization within a normalized emittance (90%) of 0.8 π mm mrad, for operations at the TRIUMF cyclotron. As a result of development of the ECR primary proton source, 1.6 mA dc polarized H^- current is produced within a normalized emittance of 2 π mm mrad, suitable for high energy accelerators. The OPPIS has also been developed for use in a parity non-conservation experiment which has very severe limits on permissible helicity-correlated changes in beam current and energy

[en] A compact dc H^-/D^- ion source using multicusp magnetic plasma confinement, has been experimentally studied and optimized on the TRIUMF ion source test stand. The plasma parameters have been obtained with rapid computer controlled Langmuir probe scans. The extraction electrode configuration, originally tailored to the TR30 cyclotron requirements, has been further developed. With a 12 mm diameter extraction hole this source now provides 9 mA within a normalized emittance of 0.44 π mm-mrad and can be easily modified for lower currents of smaller emittance (1 mA H^- current with normalized emittance 0.12π.mm-mrad or 7 mA H^- current with normalized emittance 0.34π.mm-mrad). The source has proven to have low maintenance, high reliability and long filament lifetime. This paper emphasizes basic plasma parameters which determine the efficiency of H^-/D^-production. Some experimental results obtained from several versions of the extraction system are also described. (Author) 6 refs., 8 figs

[en] In conjunction with a study on the biological effects of accelerated heavy ions on rat spinal cord, we were able to assess the residual skin damage remaining 1 year postirradiation. In this study, rats were irradiated with 230-kVp fractionated doses of either X rays, carbon ions, or neon ions. Four radiation fractions were given at daily intervals. For the carbon and neon ion exposures, rats were irradiated in both the plateau and spread Bragg peak (4 cm) regions of ionization. Comparing doses that produced complete epilation with a slight suggestion of a residual radiation scar, it was found that the relative biological effectivesness (RBE) values 1 year postirradiation for the four fraction irradiations were: carbon ions (plateau ionization region), 1.06; carbon ions (spread Bragg peak ionization region), 1.88; neon ions (plateau region of ionization), 1.55; and neon ions (spread Bragg peak ionization region), 2.26. RBE values for production of paralysis after spinal cord irradiation (using the same X-ray total dose levels for comparison purposes) were in all cases higher than the RBE values obtained from assessment of residual skin injury

[en] The TRIUMF optically pumped polarized H^- ion source has been installed in a 300 keV high voltage platform connected by a 45 m beam transport line to the cyclotron. Several different extraction electrode systems have been tested in the electron cyclotron resonance (ECR) ion source generating the initial section of the source demonstrate that the beam transport depends strongly on the degree of space charge compensation. H^-currents of up to 8 μA at a neutralizer Na thickness of 5 x 10¹³ atoms cm^-2 have been transported into the 300 keV beam line. A polarized H^- beam has been accelerated in the cyclotron and a proton polarization of up to 50% has been achieved. The installation of a superconducting solenoid for further improving the source performance is planned for this summer

[en] The Withers intestinal crypt clonogenic cell assay has been used to assess the relative effectiveness of high-energy heavy ions for cell killing in this system. The radiation modalities used are 228 MeV/amu helium ions and 400 to 670 meV/amu carbon, neon, and argon ions. These high-LET particle beams have been examined and their effect on both the shoulder of the cell survival curve and the region of exponential cell killing has been examined. All ions except helium are significantly more effective than 225-kVp x rays. There is both an effect on the shoulder, evidenced in a narrowing of this region, and an effect on the exponential region where the D₀ is reduced. This latter finding is in sharp distinction to the effects of neutron beams, where the shoulder is reduced, but the D₀ is unaffected. One of the most significant observations made in these studies is that LET alone does not predict the effectiveness of the various ions. Large differences in effectiveness are seen as a function of atomic number of the particle, even though the LET is held approximately constant

[en] The TRIUMF Lamb-shift polarized ion source produces 1.5 μA of H^- within a normalized emittance of 0.3 π mm-mrad in both transverse planes and is routinely used to produce up to 200 nA of polarized protons between 200 and 500 MeV. This source is presently being upgraded to satisfy current experimental requirements. An rf spin filter and a rapid spin reversal system are being installed in a compact, magnetically-shielded design. The duoplasmatron will be replaced by an electron cyclotron resonance proton source. In order to meet future experimental needs, development has started on an intense polarized H^- ion source (IPHIS) which is expected to yield currents in excess of 50 μA. This source, which uses of charge exchange reaction between an intense 5 keV proton beam and an optically pumped sodium vapour, is presently being assembled in the laboratory. The status and results of both programs are described

[en] The initial goal of a polarized proton beam extracted from the TRIUMF cyclotron, having a current of 5 μA with 60% polarization, has been achieved with the development of the optically pumped polarized H^- ion source. This beam is now being used to produce an intense secondary beam of polarized neutrons for the TRIUMF experimental program. Much of the recent development effort has addressed the reliability requirements for routine operation. This paper describes the results with emphasis on the laser stabilization subsystem, the modifications to the electron cyclotron resonance proton ion source (ECRIS), the sodium charge exchange cells and the development of a low energy polarimeter. Also discussed are the developments which should lead to a higher polarization. (Author) 7 refs

[en] The SuperSafe© Reactor (SSR), has been recently proposed¹ as a small modular version of the Canadian Supercritical Water Cooled Reactor (SCWR)² . This reactor is a heavy water moderated, pressure tube reactor using supercritical light water as coolant. The current SSR design is to generate 300 MWe taking advantage of the expected high thermal efficiency (assumed 45%). As one of the reactor types being considered by the Generation-IV International Forum, it is expected that this SCWR design will feature enhanced proliferation resistance over current generation technologies. Proliferation resistance assessments are wide-ranging, multidisciplinary efforts that are typically performed at a number of levels, from a state level down to a specific facility level. One small, but particularly important, sub-assessment is that of nuclear material attractiveness, that is, assessing the quality of nuclear materials throughout the fuel cycle for use in making a nuclear explosive device. The attractiveness of materials for three different SSR fuel options is examined in this work. (author)