No abstract available

[en] Noise signals can yield information on both the dynamic and steady-state performance of a system. Application of signal noise presents many challenges which can be met successfully, resulting in significant benefits. The concept and characteristics of signal noise and the benefits that can be obtained through use of signal noise are discussed. Results from practical applications to nuclear systems are given with emphasis on applications to the Gentilly-1 reactor

No abstract available

[en] Bucklings derived from activation measurements in the ZED-2 reactor are given for 19-element natural uranium metal assemblies. Measurements were made in triangular arrays of 55 assemblies at pitches in the range 20 to 40 cm. 'Coolants' used were: (1) D₂O of moderator purity, (2) He to simulate a voided condition. Bucklings obtained with He as coolant are higher than those for D₂O coolant for the pitches investigated. (author)

[en] Propagation of inherent inhomogeneities or tracers in flowing liquids is used to measure flow. The peak value obtained from a cross-correlation analysis of downstream and upstream sensor signals is used to determine the tracer transit time and hence the flow. Performance of a 'clamp-on' ultrasonic cross-correlation flowmeter developed by Canadian General Electric under contract from Atomic Energy of Canada Limited (AECL) was evaluated at the Chalk River Nuclear Laboratories of AECL. During this work, the effects of: (1) cross-correlation parameters, (2) filtering of correlator output and (3) use of an add-only polarity coincidence correlator on the standard deviation of transit measurements were investigated both theoretically and experimentally. Comparison of ultra-sonic cross-correlation flowmeter readings against gravimetric flow measurements gave a standard deviation of 2% of reading. (author)

[en] Deterministic safety analysis for the Pickering 'A' and Bruce 'A' nuclear generating stations were reviewed. The methodology used in the evaluation and assessment was based on the concept of 'N' critical parameters defining an N-dimensional safety parameter space. The reviewed accident analyses were evaluated and assessed based on their demonstrated safety coverage for credible values and trajectories of the critical parameters within this N-dimensional safety parameter space. The reported assessment did not consider probability of occurrence of event. The reviewed analyses were extensive for potential occurrence of accidents under normal steady-state operating conditions. These analyses demonstrated an adequate assurance of safety for the analyzed conditions. However, even for these reactor conditions, items have been identified for consideration of review and/or further study, which would provide a greater assurance of safety in the event of an accident. Accident analyses based on a plant in a normal transient operating state or in an off-normal condition but within the allowable operating envelope are not as extensive. Improvements in demonstrations and/or justifications of safety upon potential occurrence of accidents would provide further assurance of adequacy of safety under these conditions. Some events under these conditions have not been analyzed because of their judged low probability; however, accident analyses in this area should be considered. Recommendations are presented relating to these items; it is also recommended that further study is needed of the Pickering 'A' special safety systems

[en] Canadian experience in applying reactor noise measurement techniques to the development of the CANadian Deuterium Uranium (CANDU) pressure tube reactor system is reviewed. Application of reactor noise analysis techniques in the CANDU-BLW power reactor, Gentilly-1, is discussed since the work has demonstrated the role of noise measurements in commercial stations. Gentilly-1 with Boiling Light Water (BLW) coolant in the channels and a positive void feedback provided an ideal opportunity for assessment of the use of reactor noise techniques in power reactor systems. Consequently programs using both (1) inherent and (2) imposed excitation were carried out. Results from both programs are presented and their significance in satisfying program objectives is discussed. (U.K.)

[en] Plant performance can be improved by noise analysis. This paper describes noise characteristics, imposed noise and response functions, a case history of cost benefits derived from application of noise analysis techniques, areas for application of noise analysis techniques with special reference to the Gentilly-1 nuclear generating station, and the validity of noise measurement results. (E.C.B.)

[en] Two long-term delayed response characteristics have been observed for platinum, Pt, detectors in the Gentilly-2 600 MW(e) CANDU PHWR reactor. The first effect is a dip in the signal two to three hours after a shutdown, due to the (n,beta) interactions of Mn-55 and Ni-64 which exist as impurities in the detector assembly. The second effect is an increase of the delayed fraction of the signal. The low neutron absorption cross-section of Pt-196 combined with the conversion of the Pt-194 and Pt-195 results in build-up of the Pt-196. The long half-lives associated with the beta-emission in the transmutation of Pt-196 to Hg-198 or Hg-199 give rise to the observed long-term delayed response

[en] An ultrasonic cross-correlation flowmeter, developed to assist in improving performance of heavy water plants, was evaluated. Overall performance of the flowmeter is satisfactory. The flowmeter is ideally suited to industrial applications and has an accuracy and repeatability comparable to many laboratory instruments. An accuracy of 3% is readily obtainable. This new 'clamp-on' portable flowmeter should prove useful in applications which provide flow measurements in systems where pipe penetration is too costly or not practical, verify or replace existing flowmeters, and measure flows in lines not previously instrumented to provide better control or to verify performance of systems