Changes between Version 21 and Version 22 of GuarDyan_features

Timestamp:

Aug 30, 2017, 10:18:24 AM (7 years ago)

Author:

dieda

Comment:

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GuarDyan_features

@@ -116 +116 @@
 
 == Variance Reduction
-The time dependent tracking of the neutron population in a multiplying, near critical medium is very challenging in terms of Monte Carlo convergence. A naive analog game in most cases would statistically diverge, moreover  it will give  an underestimate of the power as the very low chance contributions of a high number of fission in certain chains. Therefore the calculation is performed always keeping a single particle as a sample of the neutron population gaining or loosing weight at interactions. The neutron weight distribution must be kept around the mean for ensuring statistical convergence. 
+The time dependent tracking of the neutron population in a multiplying, near critical medium is very challenging in terms of Monte Carlo convergence. A naive analog game in most cases would statistically diverge, moreover  it will give  an underestimate of the power as the very low chance contributions of a high number of fission in certain chains see Fig. 7. Therefore the calculation is performed always keeping a single particle as a sample of the neutron population gaining or loosing weight at interactions. The neutron weight distribution must be kept around the mean for ensuring statistical convergence. 
 The neutrons are followed from time interval to time interval and the population at the interval ends using splitting and Russian roulette while keeping the total population number constant. 
-Having single, unbranched chain calculations also supports the architecture of the GPU where threads can be set to single neutron chains.   
+Having single, non-branching  calculations also supports the architecture of the GPU where threads can be set to single neutron chains.   
+
+[[Image(TDMCC_varP_analog_vs_nonanalog.png​​, 70%)]]
+
+''' Fig. 7. Analog and non-analog simulation results for time dependent power evolution for a multiplying medium. Analog simulation produces an underestimate of the power '''
+
+Biased sampling schemes are applied at fission yield, delayed neutron, interaction type sampling with ongoing development regarding path length sampling and angular biasing.
+
+== Dynamic Capabilities
+GUARDYAN is meant to be a dynamics Monte Carlo code with thermohydraulic feedback. The current state of the code support time dependent cross section changes without feedback effects.
 
 
-== Dynamic Capabilities
 == Validation
+
+GUARDYAN  is being validated against MCNP6, using ENDF-B.VII.I. Benchmarking geometries and tallies involve homogenously filled spheres with a point source in the middle and total leakage and flux energy-time spectra are calculated by both codes and results compared. Fluxes after certain interactions also compared for some isotopes.
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 == Project Participants & Contacts
 == Publications