Abstract
Average BWR assembly cross-sections for nominal conditions, namely for zero bypass void, can be utilised in the analysis of transient conditions with boiling in the bypass. A model is developed to yield an effective channel void for such conditions. The use of this void in conjunction with the `nominal conditions` cross section library approximately preserves the assembly K-infinity corresponding to the true channel and bypass voids. The effective void is an augmentation of the actual channel void. The augment is proportional to the bypass-to-channel volume ratio, to the bypass void, and to a weight W which is introduced to quantify the fact that a water molecule in the bypass has a different assembly criticality worth than one in the channel. The formula developed is superior to the practice of choosing W=1, namely a simple, non-weighted, transfer of water from channel to bypass. The use of this approximate effective channel void reproduces actual K-infinity values of assemblies to better than 5 mk, whereas the use of a simple model sometimes misspredicts the assembly K-infinity by 40 mK. The effective void model cannot handle cases in which both channel and bypass void value are high, simply because then the effective void {alpha}{sub
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Galperin, A;
Segev, M;
[1]
Knoglinger, E
[2]
- Ben-Gurion Univ. of the Negev, Beersheba (Israel)
- Paul Scherrer Inst. (PSI), Villigen (Switzerland)
Citation Formats
Galperin, A, Segev, M, and Knoglinger, E.
Effective void fraction for a BWR assembly with boiling in the bypass region.
Switzerland: N. p.,
1991.
Web.
Galperin, A, Segev, M, & Knoglinger, E.
Effective void fraction for a BWR assembly with boiling in the bypass region.
Switzerland.
Galperin, A, Segev, M, and Knoglinger, E.
1991.
"Effective void fraction for a BWR assembly with boiling in the bypass region."
Switzerland.
@misc{etde_10111431,
title = {Effective void fraction for a BWR assembly with boiling in the bypass region}
author = {Galperin, A, Segev, M, and Knoglinger, E}
abstractNote = {Average BWR assembly cross-sections for nominal conditions, namely for zero bypass void, can be utilised in the analysis of transient conditions with boiling in the bypass. A model is developed to yield an effective channel void for such conditions. The use of this void in conjunction with the `nominal conditions` cross section library approximately preserves the assembly K-infinity corresponding to the true channel and bypass voids. The effective void is an augmentation of the actual channel void. The augment is proportional to the bypass-to-channel volume ratio, to the bypass void, and to a weight W which is introduced to quantify the fact that a water molecule in the bypass has a different assembly criticality worth than one in the channel. The formula developed is superior to the practice of choosing W=1, namely a simple, non-weighted, transfer of water from channel to bypass. The use of this approximate effective channel void reproduces actual K-infinity values of assemblies to better than 5 mk, whereas the use of a simple model sometimes misspredicts the assembly K-infinity by 40 mK. The effective void model cannot handle cases in which both channel and bypass void value are high, simply because then the effective void {alpha}{sub ch}{sup eff} becomes meaningless. A method to treat the {alpha}{sup eff}>1 domain is developed by which corrections to cross sections are provided. Such corrections are synthesised as functions of the assembly parameters. (author) figs., tabs., refs.}
place = {Switzerland}
year = {1991}
month = {Sep}
}
title = {Effective void fraction for a BWR assembly with boiling in the bypass region}
author = {Galperin, A, Segev, M, and Knoglinger, E}
abstractNote = {Average BWR assembly cross-sections for nominal conditions, namely for zero bypass void, can be utilised in the analysis of transient conditions with boiling in the bypass. A model is developed to yield an effective channel void for such conditions. The use of this void in conjunction with the `nominal conditions` cross section library approximately preserves the assembly K-infinity corresponding to the true channel and bypass voids. The effective void is an augmentation of the actual channel void. The augment is proportional to the bypass-to-channel volume ratio, to the bypass void, and to a weight W which is introduced to quantify the fact that a water molecule in the bypass has a different assembly criticality worth than one in the channel. The formula developed is superior to the practice of choosing W=1, namely a simple, non-weighted, transfer of water from channel to bypass. The use of this approximate effective channel void reproduces actual K-infinity values of assemblies to better than 5 mk, whereas the use of a simple model sometimes misspredicts the assembly K-infinity by 40 mK. The effective void model cannot handle cases in which both channel and bypass void value are high, simply because then the effective void {alpha}{sub ch}{sup eff} becomes meaningless. A method to treat the {alpha}{sup eff}>1 domain is developed by which corrections to cross sections are provided. Such corrections are synthesised as functions of the assembly parameters. (author) figs., tabs., refs.}
place = {Switzerland}
year = {1991}
month = {Sep}
}