No abstract available

[en] Ontario Hydro nuclear operations place a high priority on operating procedures and operating staff training. Computer simulations of system behavior under a variety of nonroutine conditions are an invaluable tool for improving procedures and training. In this paper the authors present and discuss verifications of this operations simulation code. This verification process is always regarded as an important part of assessing the code's ability to predict plant operational transients. The SOPHT (Simulation of PHWR Heat Transport) computer program was initially developed in 1970 and completely redesigned in 1974 to 1975 to meet the requirements for Bruce Nuclear Generating Station-A commissioning and operations. The code's characteristics, development, and applications to Bruce-1 Generating Station commissioning tests are discussed

[en] Pipecolic acid (PA) is an intermediate of L-lysine metabolism in the brain. PA has been shown to have an interaction with the gamma-aminobutyric acid (GABA) transmission. ³H-PA binding to crude synaptic membranes of bovine brain was studied in an attempt to identify and characterize the specific binding of PA to its own membrane binding site independent of the GABA receptor. Specific ³H-PA binding to synaptic membrane is saturable. Equilibrium between ³H-PA and the binding sites is reached within 60 min with a linear dependency on the membrane protein concentration up to 2 mg/ml. This binding is dependent on Na⁺ and Mg²⁺. Dialysis of the synaptic membrane increases the signal to noise ratio of ³H-PA binding. Scatchard analysis revealed that dialysis for 3 days significantly increased the maximal binding capacity over that for 20 day dialysis (B/sub max/ from 0.32 to 1.7 pmol/mg) without significantly altering the apparent dissociation constant (K/sub D/ = 55 to 67 nM). Displacement of specific ³H-PA binding by L- and D-PA is stereospecific (IC₅₀ = 4.6 x 10^-6M and 5.6 x 10^-5M). IC₅₀ for GABA and L-proline are 3.6 x 10^-4M and 6.4 x 10^-6M. Nipecotic acid, isonipecotic acid, bicuculine, hexobarbital, picrotoxin and piperidine are not active. ³H-PA binding is inhibited by GTP in a concentration (10^-6 - 10^-4 M) dependent manner, suggesting that PA binding to brain membrane may be coupled to adenylate cyclase in the brain

[en] L-lysine and its metabolite pipecolic acid (PA) have been studied for their effects on pentylenetetrazol (PTZ)-induced seizures in mice. L-Lysine of L-Pa i.p. significantly increased clonic and tonic latencies in a dose-dependent manner against 90 mg/kg PTZ-induced seizures. L-Lysine but not L-Pa enhanced the anticonvulsant effect of diazepam (DZ). L-Pa i.c.v. showed a slight decrease in clonic latency; it did not enhance the antiseizure activity of DZ; it caused seizures at 0.6 mmol/kg. D-PA i.c.v. displayed an opposite effect compared to its L-isomer. The anticonvulsant effect of L-lysine in terms of increase in seizure latency and survival was even more amplified when tested with a submaximal PTZ concentration. L-Lysine showed an enhancement of specific ³H-flunitrazepam(FZ) binding to mouse brain membranes both in vitro an din vivo. The possibility of L-lysine acting as a modulator for the GABA/benzodiazepine receptors was demonstrated. Since L-PA showed enhancement of ³H-FZ binding only in vitro but not in vivo, the anticonvulsant effect of L-PA may not be linked to the GABA/benzodiazepine receptor

[en] SORO is a critical tool for reactor fueling and fueling studies at Ontario Hydro. A recent application of up-to-date information system technology provided the fuel and physics staff with sufficient computing capacity, made our work simpler, and made emergency recovery easier at about the same cost as the previous system. The increase of productivity has made it possible to reduce staff by 2 persons, i.e., 17% of total human resources

[en] Short communication

[en] The SOPHT code was assessed against Bruce Nuclear Generating Station B commissioning data from a heat transport system rapid cooldown. It was found that (a) under a rapid upstream depressurization, the steam relief valves, like orifices, had a lower discharge coefficient than the corresponding steadystate value and (b) the flashing of water in the steam generators during depressurization causes the at-power boiling heat transfer correlations to overpredict the steam generator heat transfer

[en] Efficient nuclear power generation has become increasingly important as the cost of fueling increases and license restrictions on power limits become more stringent. Accurate knowledge of operating reactor power is not only essential to maintain nuclear unit operation at its maximum capacity rating without violating safe operating margins, it is also important to provide a reference for monitoring plant performance. A reactor power calibration method and two types of plant performance indicators have been developed at Ontario Hydro. One of the performance indicators is the conversion effectiveness (CONEFF). CONEFF eliminates the effect of changes in system boundary conditions that are beyond the control of local station management, such as the power system controlled load levels and lake water temperatures. CONEFF is a cost-effectiveness indicator, which may be directly factored into local management's decision for maintenance plans. The other performance indicator is the Turbine Efficiency Monitoring Program (TEMP) and is a problem-solving tool for technical or operating personnel. The program includes the monitoring of several turbine cycle performance parameters and an A1 turbine model, which predicts the expected values of the monitored parameters under the current operating conditions. Causes for any change of efficiency may be identified by the deviations of one or more of the monitored parameters

[en] A method of efficiency calibration for the measurement of ⁸⁸Kr and ¹³⁸Xe by HPGe γ-spectrometer is proposed in the present paper. The question for the efficient calibration is, how to achieve homogeneous sources of ⁸⁸Kr-⁸⁸Rb and ¹³⁸Xe-¹³⁸Cs. The fission product gases were obtained by irradiating a precisely measured amount of U₃O₈ (90% ²³⁵U) filled in a quartz glass ampoule. Source cell was first filled up with stearic acid, and then the fission product gases were charged into it. Xenon and krypton are not adsorbed on stearic acid, therefore, homogeneous sources of ⁸⁸Kr-⁸⁸Rb and ¹³⁸Xe-¹³⁸Cs can be prepared. The results of the experiment demonstrate that the method is feasible and successful. (author)

[en] A method of efficiency calibration for the measurement of ⁸⁸Kr and ¹³⁸Xe by HPGe γ spectrometer was proposed in the present paper. The efficiency calibration of their decay daughters ⁸⁸Rb and ¹³⁸Cs were first conducted by utilizing of their liquid sources, then the calibration measurements of ⁸⁸Kr and ⁸⁸Rb or ¹³⁸Xe and ¹³⁸Cs were be carried out by prepared homogeneous sources of ⁸⁸Kr-⁸⁸Rb and ¹³⁸Xe- ¹³⁸Cs. The calibrated efficiency of ⁸⁸Kr and ¹³⁸Xe can be obtained by using the decay relationship between ⁸⁸Kr and ⁸⁸Rb or ¹³⁸Xe and ¹³⁸Cs. Obviously, the key for the efficiency calibration is how to achieve the homogeneous sources. The fission product gases were obtained by irradiating quantitative U₃O₈(90% ²³⁵U ) filled in a quartz glass ampoule. Due to the adsorption or sedimentation, their solid decay daughters. will be not homogeneous in the source cell if the fission product gasses were directly filled into the vacua ted cell. In order to prepare homogeneous calibration sources, granules of stearic acid was used in this work. Source cell was first filled up with stearic acid, and then the fission product gases were charged into it. The apparatus for preparation of the calibration sources was showed in Fig.1. Xenon and krypton are not adsorbed on stearic acid, therefore the homogeneous sources of ⁸⁸Kr-⁸⁸Rb and ¹³⁸Xe-¹³⁸Cs can be prepared. The results of the experiment demonstrate that the method is feasible and successful.